Activated carbon-supported lanthanum nickel oxide (LaNiO3 ) perovskite nanocomposite supercapacitor electrode material exhibiting superior power-density and life cycle

Activated carbon-supported lanthanum nickel oxide (LaNiO3 ) perovskite nanocomposite supercapacitor electrode material exhibiting superior power-density and life cycle | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Activated carbon-supported lanthanum nickel oxide (LaNiO3 ) perovskite nanocomposite supercapacitor electrode material exhibiting superior power-density and life cycle Buddhodev Chowdhury, Amrit Sahis, Bibhatsu Kuiri, Ardhendu Patra, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4550514/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 19 You are reading this latest preprint version Abstract Perovskite LaNiO 3 was synthesized with the help of the sol-gel method and LaNiO 3 @AC nanocomposite was produced via ultrasonication followed by filtration process keeping LaNiO 3 and activated carbon (AC) in an NMP solvent. The prepared electrode material was then coated on Ni foam with a mass loading of 28 mg/cm 2 . Various well-known characterization techniques such as TGA, FTIR, XRD, FESEM, and XPS were used to characterize the crystal structure and surface morphology of the sample. The electrochemical performance of the prepared electrodes was measured with cyclic voltammetry (CV), galvanometric charge-discharge (GCD), and electrochemical spectroscopy (EIS) using 3 M KOH as an electrolyte solution in two electrode configurations. The pure LaNiO 3 electrode exhibits a specific capacitance (C s ) of 177.53 F/g at 5 mV/s, cyclic stability with 73.35% capacitance retention after 3000 cycles, energy density of 24.65 W h/kg, and a power density of 1.48 kW/kg. whereas, The LaNiO 3 @AC nanocomposite electrode delivered a high C s of 218.57 F/g at a 5 mV/s scan rate with excellent cyclic stability of about 94.57% specific capacitance retention after 3000 cycles, the outstanding energy density of 30.35 W h/kg with a high-power density of 1.58 kW/kg. Additional investigation on the storage contribution using Dunn's, b-fitting, and Randel Savic models produced superior results with the LaNiO 3 @AC nanocomposite electrode than with the LaNiO 3 electrode. DFT analysis further demonstrated LaNiO 3 material's strong electrochemical characteristics and stability. Thus, the LaNiO 3 @AC composite material can be the newest member of the supercapacitor electrode material with superior electrochemical performance. Perovskite Nanocomposite Supercapacitor Energy storage Energy contribution DFT Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1. Introduction Contemporary human civilization relies extensively upon fossil fuels as its primary reservoir of energy, yet it is imperative to acknowledge that this energy reservoir is subject to a swift and inexorable decline [ 1 ], [ 2 ], [ 3 ], [ 4 ]. Moreover, those types of energy set free huge amounts of pollution into the environment [ 5 ], [ 6 ], [ 7 ], [ 8 ]. To resolve this, pollution-free renewable energy sources are required. Additionally, energy storage devices such as electrolytic capacitors or electrochemical batteries [ 9 ], [ 10 ], [ 11 ] are to be employed with them. A supercapacitor exhibits a notable power density (> 10 kW/kg), although its energy density remains comparatively lower (5 W h/kg). Addressing this disparity necessitates enhancements within the realm of contemporary energy storage mechanisms [ 12 ], [ 13 ]. Otherwise, it has a lot of advantages, such as a long cycle life (> 100,000 cycles), fast charging and discharging, a broad range of working temperatures (-40 ℃ to 70 ℃), and low maintenance cost [ 3 ], [ 12 ], [ 13 ], [ 14 ], [ 15 ], [ 16 ], [ 17 ], [ 18 ]. Numerous studies have been conducted on transition metal oxides and carbon materials such as NiO nanosheets (C s 81.67, 3 M KOH aqueous electrolyte, current density 0.5 A/g) [ 19 ], La 2 O 3 thin film (C s 147 F/g, 1 M KOH aqueous electrolyte, scan rate of 5 mV/s) [ 20 ], Phosphorus-doped porous carbon (C s 209 F/g, 6 M KOH aqueous electrolyte, current density of 0.5 A/g [ 21 ], C s 127 F/g, Na 2 SO 4 @KBr aqueous electrolyte, current density at 3.8 A/g [ 22 ], C s 220 F/g 2 M KOH aqueous electrolyte, scan rate of 5 mV/s) [ 23 ], Heteroatom self-doped graphitic carbon electrode (C s 248 F/g, 6 M KOH electrolyte, current density of 10 A/g) [ 24 ], further investigated a few composite materials made of carbon and transition metal oxides like MnO 2 /AC (C s 421.5 F/g, 2 M KOH electrolyte, scan rate 0.5 A/g) [ 25 ], FeO/AC (C s 168.5 F/g, 1 M Na 2 SO 4 , current density of 2 A/g) [ 26 ], ZnO/AC (C s 178.2 F/g, 6 M KOH aqueous electrolyte with current density 1 A/cm 2 ) [ 27 ], Fe 3 O 4 /AC (C s 131 F/g, 6 M KOH aqueous electrolyte, scan rate 5 mV/s) [ 28 ], NiO/AC (C s 107 F/g, 6 M KOH electrolyte, scan rate of 5 mV/s) [ 29 ], La 2 O 3 /rGO (C s 156.25 F/g, 3 M KOH aqueous electrolyte, 0.1 A/g current density)[ 30 ] etc., however, none of these had positive outcomes in every aspect. The current topic of research on perovskite materials, that has a lot to explore. The usual formula for perovskite is ABO 3 . This perovskite oxide contains two kinds of cations: an alkaline or rare-earth metal (A) such as La, Sr, Sm, Ce, Nd, Gd, Pr, Tb, Y, a 12-fold coordinated cuboctahedral cage of oxygen lattice, and a transition metal (B) such as Ti, Cr, Mn, Fe, Co Ni, Zn, etc. encompassed octahedrally by the oxygen atom, and O is the oxygen atom [ 31 ], [ 32 ]. Nearly all metal oxide electroactive materials primarily undergo cation intercalation for charge storage in supercapacitors through a rapid surface redox mechanism. In contrast, perovskite materials exhibit a distinctive capacity for anion intercalation in energy storage, attributed to their unique ABO 3 structural specificity and oxygen vacancies. Current research endeavors primarily concentrate on synthesizing numerous nanoscale metal oxide materials at the electrode level to augment the electrochemical storage capabilities of these metal oxides. Notable perovskite electrodes that have been reported recently include, a mesoporous LaFeO 3 perovskite electrode that achieved a high C s of 241.3 F/g at 1 A/g current density, it attained a broad potential window (1.8 V) which may retain capacitance for 92.2% of its life after 5000 cycles. Additionally, it has an impressive energy density and power density of 34 W h /kg and 0.9 kW/kg [ 33 ], the LaMnO 3 perovskite obtained C s of 114.4 mA h/g at 1 A/g [ 17 ], intrinsic LaNiO 3 demonstrated the highest C s of 106.58 F/g, 1 A/g current density in 3 M LiOH [ 34 ]. Moreover, LaNiO 3 retained 98% of its initial capacitance after 500 charge-discharge cycles. In this investigation, we produced a nanocomposite by combining 90 wt% of LaNiO 3 with 10 wt% high porous and conducting activated carbon denoted LaNiO 3 @AC to increase the electrical conductivity of supercapacitor electrodes as well as the power and cyclic stability of the supercapacitor also reducing the effective cost. To the best of our knowledge, no research has been reported on the LaNiO 3 @AC as a composite form. This electrode functions as both the energy storage mechanism, such as an electric double layer capacitor (EDLC) for the activated carbon material and a pseudocapacitor for the LaNiO 3 materials. To create the LaNiO 3 @AC nanocomposite, a standard precipitation technique was employed [ 20 ], [ 35 ]. The characteristics of LaNiO 3 @AC nanocomposite material were assessed by TGA, FTIR, XRD, FE-SEM, and XPS. Moreover, LaNiO 3 @AC nanocomposite electrodes effectively showed improved electrochemical performance. 2. Experimental 2.1. Synthesis of LaNiO 3 Sample By standard preparation, 1.76 gm lanthanum nitrate hexahydrate [La(NO 3 ) 3 , 6 H 2 O] (Merck, India, 99.9% pure) and 1.179 gm nickel nitrate hexahydrate [Ni(NO 3 ) 2 , 6 H 2 O] (Merck, India, 99.9% pure) dissolved in 25 ml of N, N-dimethylformamide (DMF) (Merck, India, 99.8% pure) and stirred for 2 hours. Then 0.45 gm of polyvinylpyrrolidone K-30 (Merck, India, 99% pure) was added to the solution and stirred for 1 hour, then it was kept at boiling temperature with continuous stirring until a gel formed [ 36 ]. Then the prepared gel was kept in a crucible and placed in an oven at 200 ℃ for drying and the dried sample was placed in a muffle furnace for calcination at 600 ℃ for 3 h at the heating rate of 4 ℃/min in an air atmosphere. 2.2. Synthesis of AC and LaNiO 3 nanocomposite materials Simultaneously stirred and ultrasonicated activated carbon (Alfa Aesar, VA, USA, 99.5% pure) and lanthanum nickel oxide (LaNiO 3 ) individually kept in N-methyl-2-pyrrolidone (NMP) medium (Merck, 99.5% pure) until dispersed well. Then, 10 wt% of AC and 90 wt% LaNiO 3 were collected from the solvent and mixed through the ultrasonicated keeping 20 ml of NMP solvent for 2 hours. Further, LaNiO 3 @AC nanocomposite was collected by filtration process [ 37 ], [ 38 ], [ 39 ]. 2.3. Fabrication of working electrodes For preparing the working electrode, a mixture of 80 wt% of active materials, 10 wt% of PVDF (Sigma Aldrich) binder, and 10 wt% of acetylene black (Alfa Aesar, VA, USA, 99.9% pure) in NMP. Once thoroughly mixed, it was coated on a nickel foam substrate (0.8 cm × 0.8 cm) which was cleaned with 3 M HCl and distilled water. The amount of total electrode material was 28 mg/cm 2 . The electrode was heated in an oven at 80 ℃ overnight to eliminate the NMP solvent. After this, compression was enacted utilizing a hydraulic pressure of 10 MPa. A supercapacitor cell was assembled employing two indistinguishable electrodes while interposing a separator akin to filter paper amid the aforementioned electrodes, preparatory to undertaking measurements [ 37 ]. The whole procedure is illustrated in Fig. 1 . 2.4. Characterization TGA analysis (USA, Perkin-Elmer, STA 6000) was used to determine the material's thermal stability by gradually increasing temperature by 2°C /min, starting from 50°C to 800°C, The crystalline structure of the material was investigated by using X-ray diffractometer (XRD) (Rigaku, Smart Lab) with Cu-K α radiation (λ = 1.54056 Å) at room temperature and the angle of the collecting data starting from 10° to 80° with a scan rate of 4°/min., the surface morphology of the sample was examined by using field-emission scanning electron microscope (FESEM) (Jeol, JSM-IT300HR, Japan) fitted with a dispersed energy x-ray (EDX). To confirm the prepared nanocomposite electrode materials, the Fourier Transform Infrared Spectroscopy (FTIR) (Perkin-Elmer L120-00A, FT-IR spectrometer, IR spectra) instrument was used at a range of wavenumber from 450–4000 cm − 1 keeping the sample in KBr pellets and X-ray photoelectron spectroscopy (XPS) (JPS − 9030, Jeol, Japan) using an Al-K α source was utilized to assess the material's surface elemental makeup and ascertain the elements binding status. 2.5. Electrochemical measurement All electrochemical measurements were performed by using cyclic voltammetry with the two-electrode system using 3 M KOH as a potent aqueous electrolyte to facilitate charge transfer with complete dissociation into K + and OH − ions in aqueous solution, operated at CHI660E electrochemical workstation at room temperature. Cyclic voltammetry (CV) and galvanometric charge discharging (GCD) measurements of supercapacitors were carried out with a potential window range of -1 to 1 V. The electrochemical impedance spectroscopies (EIS) of supercapacitors were taken within 0.01 Hz and 100 kHz. The C s value of a single electrode was measured by cyclic voltammetry from Eq. (1) and galvanometric charge discharging was measured from Eq. (2). The energy density ( E s ) (W h/kg), and power density ( P s ) (kW/kg) of supercapacitor cells were measured by equations (3) and (4) [ 21 ], [ 40 ], [ 41 ]. $${C}_{S}=\left[\frac{1}{\nu \varDelta V}\underset{{V}_{1}}{\overset{{V}_{2}}{\int }}{I}_{1}\left(V\right)dV\right]\times \frac{4}{m} \left(1\right)$$ $${ C}_{S}=\frac{{I}_{2}\varDelta t}{\varDelta V} \times \frac{4}{m} \left(2\right)$$ $${E}_{s}=\frac{1}{8}{C}_{s}({\varDelta V)}^{2}\times \frac{1}{3.6} (3)$$ $${P}_{s}=\frac{{E}_{s}}{\varDelta t} \times 3.6 \left(4\right)$$ Where m is the total mass of two electrode materials, υ (V/s) denotes scan rate, ∆V (V) denotes potential window, I 1 (A) is the voltammetric current, I 2 (A) is discharge current, and ∆t (s) denotes discharging time. 3. Results and Discussion 3.1. Characterization of LaNiO 3 and LaNiO 3 @AC nanocomposite 3.1.1. Thermal analysis Thermogravimetric analysis (TGA) of the prepared gel after heating at 180 ℃ (before calcination) is executed under a nitrogen gas flow rate of 20 ml/min and with a temperature range of 30 ℃ to 800 ℃ for assessing the thermal stability shown in Fig. 2 (a). The first phase weight loss of LaNiO 3 perovskite was started from 180°C to 295°C at a slow rate, and this weight loss (3.5 wt%) was due to the decomposition of a small amount of organic DMF solvent into various byproducts like CO 2 , H 2 O (g), etc. The second phase of weight loss (40.85 wt%) has a sharp peak and lasts from temperatures above 295°C to almost 585°C due to the degradation of PVP-K-30. In the third phase, which lasted from 580°C to 800°C, there was no weight loss observed which means in this temperature range only the LaNiO 3 perovskite material existed. [ 2 ]. 3.1.2. FTIR spectroscopy The FTIR spectroscopy was used to distinguish the functional groups in the LaNiO 3 @AC nanocomposite in Fig. 2 (b). A broad peak was found at 3436.35 cm − 1 which indicates stretching vibrations of the O–H bond due to moisture. The peak at 2937.31 cm − 1 represented the existence of C-H stretch, and another peak near it at 2882.10 cm − 1 was due to C-H 2 symmetric stretching. The peak at 1667.89 cm − 1 may be due to the C = O stretching vibration The peaks at 1505.88 cm − 1 and 1446.75 cm − 1 are caused by the aromatic functional group's C-C stretching vibration. The peak at 1405.94 cm − 1 may be due to the stretching vibration of the C = O bond. Also, some weak bands were found between 1114.44 cm − 1 − 1302.67 cm − 1 which may be due to the existence of C-O groups. The peak at 658.22 cm − 1 could be caused by an alkene's C = C stretching vibration. The La-O and Ni-O metal oxides detected in the LaNiO 3 @AC nanocomposite are shown by the peaks located at 566.33 cm − 1 and 472.62 cm − 1 , respectively [ 42 ], [ 43 ]. 3.1.3. XRD analysis XRD was employed to ascertain the crystalline structure or composition of a sample. Distinct peaks corresponding to the desired materials were assured about the absence of any impurities of the materials. The synthesized process of two-dimensional perovskite LaNiO 3 was represented in Fig. 1 . In this experiment La and Ni ions coming from their respective nitrate salt quickly react with the precursor N, N-dimethylformamide (DMF) to form the perovskite structure under the presence of polyvinylpyrrolidone K-30 for assistance to minimize the size of the particle at the nanoscale. Prepared LaNiO 3 initially is an amorphous structure and after heating with high temperature converted 2D perovskite crystal structure [ 2 ]. The structural information of the prepared LaNiO 3 sample was known by X-ray diffraction. Figure 3 (a) indicates the XRD patterns of the sample showing broad and weak peak shapes[ 37 ], [ 44 ], [ 45 ], [ 46 ], [ 47 ]. Grain size of nanocrystalline materials was measured by the Eq. (5). $$D =\frac{K\lambda }{\beta cos\theta } \left(5\right)$$ Where D, K, λ, β, and θ are the average grain size, constant (usually set as at 0.9), wavelength (Cu-K α ) valued at 1.54056 Å, the full width at half maximum intensity, and Bragg’s angle in degree, respectively. The average grain size of the prepared LaNiO 3 sample was 16.40 nm which was approximately the same as pure LaNiO 3 perovskite material with a rhombohedral structure with the cell parameters (a = 5.460511 Å, b = 5.460511 Å, c = 13.139636 Å; α = 90°, β = 90°, γ = 120°) and R-3c space group. The result proved that the sample was successfully generated and performed best when heated to 600°C for 3 hours, out of all the different heating temperatures and times [ 2 ], [ 47 ]. The sample's sharp diffraction peak intensity was discovered, indicating that under these circumstances, a high crystalline structure had formed in the sample. Figure 3 (b) represents the XRD graph of the AC sample. XRD patterns of LaNiO 3 @AC nanocomposite were found to be the same as the mentioned LaNiO 3 patterns that could be AC layers were completely immersed by the LaNiO 3 layers and, the peaks of AC were not separately found as shown in Fig. 3 (c). 3.1.4. SEM images The scanning electron micrograph shows the high porosity as observed in Fig. 4 . The black spots indicate the porosity of the LaNiO 3 material. There are certain channels also observed, as indicated by the large black areas in Fig. 4 (a) [ 48 ]. Figure 4 (b) shows the X-ray mapping of all the elements O, Ni, and La together, indicating the homogeneous distribution of elements, which is also clearly visible from the X-ray mapping of the individual elements as shown in Fig. 4 (c), (d), and (e), respectively, for O, Ni, and La, the EDS analysis data of LaNiO 3 material are represented in Fig. 4 (f) and (g), where the element percentages present ratio are shown as O: Ni: La = 52.45: 12.95: 12.24, which are very close to the formula ratio. There is 22.37% carbon in the material, which is due to the addition of carbon black for the preparation of electrodes. Figure 5 shows that the surface area of the LaNiO 3 @AC nanocomposite material has increased due to its high porosity and small pore size compared to the LaNiO 3 material. Figure 5 (b) represents the X-ray mapping of the whole elements present in the LaNiO 3 @AC as C, O, Ni, and La altogether, thus beginning the homogeneous distribution of elements, which is also clearly visible from the X-ray mapping of the individual elements as shown in Fig. 5 (c), (d), (e), and (f), respectively, for C, O, Ni, and La. The element percentages present in the EDS analysis data of LaNiO 3 @AC nanocomposite material are shown in Fig. 5 (g) and (h), with C: O: Ni: La = 61.84: 30.08: 4.03: 4.05. Here, the ratio of carbon and oxygen atoms is greater than their formula ratio, which indicates the presence of carbon black, and some oxygen atoms react with carbon atoms. 3.1.5. XPS analysis The XPS analysis of LaNiO 3 and LaNiO 3 @AC nanocomposite materials is shown in Fig. 6 (a). The characteristic peak of La is indicated at 853.64 eV and 840.78 eV, which are for La 3d 3/2 and La 3d 5/2 , respectively. These peaks are coming for the La 3+ of perovskite LaNiO 3 and LaNiO 3 @AC nanocomposite materials, its La 3d 5/2 peak disassociation ΔE 1 = 3.9 eV, spin-orbit splitting energy is ΔE 2 = 16.9 eV for the La 3d doublet as shown in Fig. 6 (b) [ 49 ], [ 50 ], [ 51 ]. The peaks of Ni are shown at 874.55 eV and 857.80 eV due to Ni 2p 1/2 and Ni 2p 3/2 , respectively, and these peaks appear due to the presence of Ni 3+ and Ni 2+ in the perovskite LaNiO 3 and LaNiO 3 @AC nanocomposite materials as mentioned in Fig. 6 (b). A lower binding energy peak appeared at 532.03 eV, due to the presence of the O 2− anion in lanthanum oxides (La-O bond), and a higher binding energy peak at 533.67 eV displays the presence of the O 2− anion in nickel oxides (Ni-O bond), shows in Fig. 6 (c) [ 52 ]. The completely oxidized nickel ion (Ni 3+ ) in LaNiO 3 material indicates a slightly distorted rhombohedral-like perovskite cell is formed, and both ionic (Ni-O-Ni) and covalent (La-O, Ni-O) chemical bonds are present among them. Another peak has been seen at 285.11 eV on the graph of LaNiO 3 @AC nanocomposite materials in Fig. 6 (d), and it occurs due to the presence of activated carbon (C 1s). All these peaks obliquely prove the perovskite LaNiO 3 and LaNiO 3 @AC nanocomposite materials are successfully generated. 3.2. Electrochemical behaviors of LaNiO 3 and LaNiO 3 @AC nanocomposite The electrochemical execution of prepared electrodes, such as LaNiO 3 and LaNiO 3 @AC nanocomposite, was observed with the help of cyclic voltammetry (CV), galvanometric charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements with operating voltage range of -1.0 to 1.0 volt. All the measurements have been done in a two-electrode system at room temperature by making a simple supercapacitor cell by using a 3 M KOH electrolyte solution [ 2 ], [ 3 ], [ 37 ]. Firstly, the CV of LaNiO 3 along with LaNiO 3 @AC was performed at several scan rates, such as 5–100 mV/s which is plotted in Fig. 7 (a) and (b). Figure 7 (a) and (b) show that the area covered by the CV curve was different using different scan rates in a proportional relationship, and the capacitance of the supercapacitor was increasing with decreasing scan rates. The maximum capacitance values of 177.53 F/g and 218.57 F/g were observed at a 5 mV/s scan rate as shown in Fig. 7 (a) and (b) respectively for LaNiO 3 and LaNiO 3 @AC. The specific capacitance of both electrodes at all scan rates is mentioned in Table 1 . It should have a higher capacitance value when the scan rate is below 5 mV/s. The comparison of specific capacitance with scan rates for each electrode is displayed in Fig. 7 (c). The LaNiO 3 @AC electrode shows a higher capacitance value than the pure LaNiO 3 electrode due to the presence of conductive high porous AC that increases the transport speed of charges within the electrolyte and its larger surface area helps to store comparatively higher charges as well as enhances the capacitance of the electrodes. The LaNiO 3 electrode exhibits distinct oxidation and reduction peaks, indicating the oxidation-reduction reaction occurred here, and it stores electrical energy due to its pseudo-capacitive nature, whereas in CV curve of the LaNiO 3 @AC nanocomposite electrode has an almost rectangular shape, indicating an accurate electrochemical nature. This is due to activated carbon, which improves overall supercapacitor behavior [ 28 ]. The previous report showed that LaNiO 3 exhibited a capacitance value of 106.58 F/g at a current density of 1 A/g while 3 M LiOH was taken as an electrolyte. Comparative data are given in Table 2 for the relevant materials such as NiO, La 2 O 3 , NiO/AC, La 2 O 3 /rGO, etc. which confirmed the higher values in the present study in comparison to the reported values. The galvanostatic charge-discharge method is a reliable way to find the capacitance of a produced device in poorly controlled conditions. Figure 7 (d) and (e) display the GCD curve of LaNiO 3 and LaNiO 3 @AC nanocomposite electrodes respectively. A working voltage of between − 1.0 and 1.0 volts was used during the GCD process of LaNiO 3 and LaNiO 3 @AC nanocomposite electrodes. Each electrode has an almost linear discharge profile, suggesting a triangle shape similar to a capacitive type. A quick potential drop was observed during the discharging process due to the ohmic loss across the supercapacitor device's internal resistance (IR), also known as the equivalent series resistance (ESR). The GCD measurements determined the specific capacitance of LaNiO 3 @AC nanocomposite at 0.5 A/g current density to be 152.68 F/g and in the case of the LaNiO 3 electrode, the specific capacitance is 99.75 F/g at 0.5 A/g current density using Eq. (2), as shown in Fig. 7 (d) and (e). Equations (3) and (4) were used to measure the energy and power density, and the computed value is shown in Fig. 7 (f). Here, attempt to compare the energy and power density of the current and prior electrodes. According to the current investigation, the LaNiO 3 cell's energy density and power density were 24.65 W h/kg and 1.48 kW/kg, respectively, while the LaNiO 3 @AC nanocomposite cell's values were 30.35 W h/kg and 1.58 kW/kg as listed in Table 1 , which put it in a better position than the other electrodes. Table 1 Comparison of measured specific capacitance values among LaNiO 3 and LaNiO 3 @AC nanocomposite from CV and GCD measurements. C s (F/g) from CV measurement C s (F/g), E s (W h/kg), and P s (kW/kg) from GCD measurement Scan rate (mV/s) LaNiO 3 LaNiO 3 @AC Current density (A/g) LaNiO 3 LaNiO 3 @AC E s (W h/kg) & P s (kW/kg) of LaNiO 3 E s (W h/kg) & P s (kW/kg) of LaNiO 3 @AC E s (W h/kg) P s (kW/kg) E s (W h/kg) P s (kW/kg) 5 177.53 218.57 0.5 99.75 152.68 24.65 1.48 30.35 1.58 10 152.44 184.92 0.75 70.33 122.10 21.17 3.39 25.68 2.41 25 119.52 132.68 1 67.18 112.54 16.60 3.71 18.43 3.42 50 102.13 105.40 1.25 57.88 69.86 14.18 4.60 14.64 4.25 75 92.66 95.23 1.5 45.15 25.80 12.86 5.40 13.23 5.56 100 84.50 88.57 1.75 43.72 13.74 11.74 6.63 12.30 6.34 Table 2 Briefly represented the capacitance values of some metal oxides and metal oxide-activated carbon composites in previous publications. Electrode materials Electrolyte Current density/ scan rate Specific capacitance (F/g) Capacitance retention (in cycles) Ref. NiO nanosheet 3 M KOH 0.5 A/g 81.67 78.5% after 3000 [ 19 ] La 2 O 3 thin film 1 M KOH 5 mV/s 147 96% after 2000 [ 20 ] NiO/AC 6 M KOH 5 mV/s 166⋅8 92.6 after 800 [ 29 ], [ 53 ], [ 54 ] La 2 O 3 / rGO 3 M KOH 0.1 A/g 156.25 78% after 500 [ 30 ] LaNiO 3 3 M LiOH 1 A/g 106.58 98% after 500 [ 34 ] LaNiO 3 3 M KOH 5 mV/s 177.53 73.35% after 3000 [Present work] LaNiO 3 @AC 3 M KOH 5 mV/s 218.57 94.57% after 3000 [Present work] Electrochemical impedance spectroscopy (EIS) was used for studying the internal resistance and electrochemical kinetics of the above-mentioned electrodes. The acquired Nyquist plots of LaNiO 3 and LaNiO 3 @AC electrodes are displayed in Fig. 8 (a) [ 2 ], [ 44 ], [ 55 ]. An EIS spectrum analyser software was utilized to fit and simulate the EIS spectra and the corresponding circuit schematic is displayed in Fig. 8 (a) (inset) [ 56 ]. The Nyquist plots are accessed by plotting the imaginary part versus the real part of the impedance with a frequency range of 0.01 Hz to 100 kHz. An intersection observed at the high-frequency region with the real axis causes the electrode-electrolyte interface resistance known as electrolyte resistance (R s ) which is connected through the series combination of electron charge transfer resistance (R ct ) at the interface of the electrode and electrolyte which is measured by the diameter of the semi-circle appeared on Z′ axis as shown in 8 (a), Warburg impedance (Z w ) due to consideration the diffusion of ions stored at the electrode-electrolyte contact, and EDLC (C dl ) [ 40 ]. Furthermore, it incorporates an additional series circuit with a Faradaic capacitance (C f ) as well as the resistance (R 1 ) at the electrode contacts [ 1 ]. The vertical line in the comparatively low-frequency region represents the perfect capacitive properties. The electrolyte resistance (R s ) and charge transfer resistance (R ct ) values of LaNiO 3 are 0.960 Ω and 0.865 Ω respectively. Whereas, the values of R s and R ct of LaNiO 3 @AC are 0.066 Ω and 0.592 Ω respectively as seen in the EIS curve. It has been shown that the total internal resistance of the LaNiO 3 @AC nanocomposite electrode is lower than the LaNiO 3 perovskite electrode due to the presence of high porous and conductive AC on LaNiO 3 perovskite [ 57 ]. Concerning actual supercapacitor applications, LaNiO 3 @AC nanocomposite electrode exhibits excellent electrical conductivity with a higher R ct value than LaNiO 3 . Additionally, the electrochemical stability was computed using CV data from the first and subsequent 3000 CV cycles, as shown in Fig. 8 (b). The LaNiO 3 @AC nanocomposite supercapacitor electrode performed remarkable cyclic stability; the retention was 94.57% of the initial capacitance after 3000 cycles at 100 mV/s. The reason for the remarkable cyclic stability may be due to the presence of AC networks executing as an electrical double layer capacitor (EDLC), whereas LaNiO 3 retained 73.35% of its initial capacitance after 3000 cycles at 100 mV/s. While contrasting every electrode listed in Table 2 , the cyclic stability of The LaNiO 3 @AC nanocomposite electrode outperformed all other electrodes, including the LaNiO 3 electrode, this is the essential feature for the electrochemical performance of a supercapacitor. Additionally, it was shown that a supercapacitor retains total charge through both capacitive and diffusive controlled contributions. This charge contribution is quantified in a specific fixed potential using the following Dunn's equation [ 58 ]. $$i = a{\nu }^{b} \left(6\right)$$ where ν stands for scan rate, a and b are the modified parameters, and i is the voltammogram peak current. The value of b is measured by the slope of a curve plotting through log i vs log ν , which lies between 0.5 ≤ b ≤ 1. When b is close to 0.5, it indicates a diffusive regulated charge storage contribution; in this instance, the current is proportionate to ν 1/2 , conversely, b value near 1 represents a capacitive charge storage contribution, and the corresponding current is proportionate to ν , at a scan rate of 5 mV/s, the current experimental value of b , which employed in the assessment whole types of capacity for charge storage. The values of b are calculated for the LaNiO 3 electrode at 0.589 and for the LaNiO 3 @AC nanocomposite electrode at 0.595 as shown in Fig. 9 (a-b), indicates both the electrodes have diffusive and capacitive storage contribution and the higher b value of the LaNiO 3 @AC nanocomposite electrode compared to the LaNiO 3 electrode signifies an increase in capacitive charge storage contribution and improved performance [ 59 ]. Dunn's equation may also be used to compute charge storage via capacitance and diffusion is given below $$i\left(V\right)={K}_{1}\upsilon + {K}_{2}{\upsilon }^{1/2}$$ 7 or $$\frac{i\left(V\right)}{{\upsilon }^{1/2}}= {K}_{1}{\upsilon }^{1/2}+{K}_{2}\upsilon \left(8\right)$$ Where " ν " stands for the modified scan rate and K 1 ν and K 2 ν 1/2 reflect the contributions made by the capacitive and diffusion-controlled charge storage systems at this time, respectively. Utilizing Eq. (8), the graph i(v)/ v 1/2 against ν 1/2 is plotted to get the values of K 1 and K 2 , where K 1 represents the curve's slope and K 2 is the y-intercept. At a scan rate of 5 mV/s, the K 1 and K 2 values for the LaNiO 3 electrode are 0.0000056 and 0.0001, respectively, whereas, for the LaNiO 3 @AC nanocomposite electrode 0.0000104 and 0.000134 as shown in Fig. 9 (c-d), and the corresponding capacitance and diffusion-controlled charge storage of LaNiO 3 and LaNiO 3 @AC nanocomposite electrode are 12.28%, 87.72% and 14.82%,85.18%, respectively. The values of capacitance and diffusion-controlled charge storage of all scan rates from 5–100 mV/s are listed in Table 3 . This observation indicates that the LaNiO 3 @AC nanocomposite electrode performs better electrochemically than the LaNiO 3 electrode as it has a higher capacitive charge storage value, and Fig. 9 (e-f) displays the value of the capacitive charge storage contribution rises in proportion to scan rates causing a higher scan rate accelerated the capacitive contribution charge storage process. $${i}_{peak}=0.4463 n FA{C}_{o}{\left(\frac{nFD}{RT}\upsilon \right)}^{1/2} \left(9\right)$$ Where i peak denotes the peak current of the voltammogram, n stands for the number of electrons exchanged during the electrode reaction, F stands for the Faraday constant, A for electrode surface area, C o for electrode material surface concentration, D for chemical diffusion coefficient, υ for scan rate, R for molar gas constant, and T for temperature [ 60 ]. When i peak is plotted against ν 1/2 , a linear curve with a slope of {0.4463 n FAC o (nFD/RT) 1/2 } and zero intercepts on the y-axis is produced. In contrast, the slope allows for the measurement of D. The results of the current experiment demonstrate that, under identical conditions, the LaNiO 3 @AC nanocomposite electrode's D values are (0.0075) higher than those of the LaNiO 3 electrode (0.0053) as shown in Fig. 10 , suggesting that the former performs better than the latter. Table 3 LaNiO 3 LaNiO 3 @AC Scan rate (mV/s) Capacitive contribution Diffusive contribution Capacitive contribution Diffusive contribution 5 12.28 87.72 14.82 85.18 10 15.13 84.87 19.73 80.27 25 21.87 78.13 27.95 72.05 50 28.57 71.43 35.61 64.39 75 33.60 66.40 40.20 59.79 100 37.33 62.66 45.81 54.19 Figure 11. GCD curves for LaNiO 3 at 3M KOH solution at 1 A/g current density by (a) numerical modeling and (b) experiment. 4.1. Device modeling and comparing GCD Curves The numerical modeling was performed using the MATLAB platform. The Nernst equation was used to determine equilibrium potentials, while the Butler-Volmer equation described current-potential relationships. Diffusion processes were modeled using Fick's laws [ 61 ]. This numerical modeling of the charge-discharge cycle for the LaNiO 3 electrode is performed at 3 M KOH electrolyte at 1 A/g [ 62 ]. In Fig. 11 (a), the GCD curve shows a discharging time of about 20 s in 3 M KOH solution, which does not change for 3 consecutive segments but in Fig. 11 (b) we observed a discharging time near about 15.02 s, so here is a small discrepancy observed. This can be explained by recalling some attributes in our experimental measurements. i. Experimental Variability : Experiments inherently carry a degree of variability due to uncontrollable factors such as environmental conditions, impurities in materials, or variations in electrode preparation. Addressing and quantifying these sources of variability in the experimental setup can contribute to a more accurate comparison with the numerical model. ii. Temperature Influence : Temperature serves as a critical parameter in electrochemical systems, exerting a profound impact on reaction rates, ion mobility, and overall electrochemical kinetics. Disparities in the thermal conditions between the numerical model and the experimental setup can lead to variations in the observed discharging time. Also how the pseudocapacitance will come up as a result of redox reaction between KOH electrolyte and LaNiO 3 is also to be studied. 4.2. DFT and Psudocapacitance The Density of States calculation is performed for LaNiO 3 employing the Generalized Gradient Approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) functional, a widely used method for precisely describing electronic structures and properties of various materials. The LaNiO 3 crystal with space group R ͞ 3 c is used in the model, with 30 sites in its unit cell. The cell volume of 337.57 Å 3 and the density is 7.24 g/cm 3 . Lanthanum ions (La³⁺) are arranged in a 9-coordinate geometry, forming bonds with nine identical oxygen ions (O²⁻). Among these bonds, three are shorter, measuring 2.43 Å, while the remaining six are longer, extending to 2.71 Å in length. Nickel ions (Ni³⁺) are connected to six identical oxygen ions (O²⁻), creating corner-sharing NiO₆ octahedra. These octahedra exhibit corner-sharing angles of 17°. All the nickel-oxygen (Ni–O) bond lengths in this arrangement measure 1.94 Å. Oxygen ions (O²⁻) adopt a 5-coordinate geometry, forming bonds with three identical lanthanum ions (La³⁺) and two identical nickel ions (Ni³⁺) in this structural configuration as shown in Fig. 12 [63]. The geometry optimization is performed followed by the energy calculations. The band energy tolerance of ~ 10 − 5 eV is used for convergence. The Quantum ESPRESSO software package is used to perform the calculations. The valence states treated are La 5s 2 5p 6 5d 1 electrons, Ni 3d 8 4s 2 electrons, and O 2s 2 2p 4 . The total Density of States (DOS) is shown in Fig. 13 . The DOS of the total crystal structure is represented in Fig. 13 , which gives a detailed insight into the electronic structure of the rhombohedral LaNiO 3 and the contributions of p and d orbitals across the energies. Figure 14 shows the partial DOS for each of the atoms and the corresponding orbitals for each atom. The bands in the range − 8 eV to 0 eV mainly contributed by O 2p and Ni 3d orbitals. La 5d mainly contributes to the upper band around 6 eV hybridized orbital, indicating a weak La–O bond covalency. From the analysis of PDOS, the La atoms do not significantly contribute to the metallic nature of LaNiO 3 [ 47 ], [ 64 ]. Density of States (DOS) calculations for LaNiO 3 give valuable insights into the electronic structure of this material, which can be related to its pseudocapacitance behavior when used as an electrode material with a 3M KOH electrolyte. Energy Calculations and Convergence Geometry optimization and energy calculations were performed with a high band energy tolerance of ~ 10 − 5 eV, ensuring accurate results. This level of precision is crucial for understanding the electronic properties relevant to pseudocapacitance. La–O Bond Covalency The upper band around 6 eV, mainly contributed by La 5d hybridized orbitals, indicates a weak covalency in the La–O bond. This insight is valuable because it hints at the nature of chemical interactions between La and O, which can influence pseudocapacitance behavior. Role of La Atoms From the partial DOS (PDOS) analysis, it is observed that La atoms do not significantly contribute to the metallic nature of LaNiO 3 . This is important because it suggests that the pseudocapacitance behavior primarily arises from the electronic states associated with Ni and O. LaNiO 3 is known for its mixed-valence state, where nickel ions (Ni 3+ and Ni 4+ ) can undergo reversible redox reactions. The KOH electrolyte dissociates into potassium (K + ), hydroxide (OH − ) ions, and water (H 2 O). The OH − ions play a crucial role in pseudocapacitive reactions. Pseudocapacitance arises from faradaic (redox) reactions that occur at the electrode-electrolyte interface. In the case of LaNiO 3 and KOH, here's how the pseudocapacitance reaction takes place: a. Oxidation of Ni : During the charging process (oxidation), Ni 3+ ions in LaNiO 3 lose electrons and transform into Ni 4+ ions. This is a redox reaction that stores charge. b. Hydroxide Ion Adsorption : Simultaneously, OH − ions from the KOH electrolyte adsorb onto the surface of LaNiO 3 , forming Ni-OH surface groups. This adsorption process is highly reversible. c. Reduction of Ni : During the discharging process (reduction), Ni 4+ ions gain electrons and revert to Ni 3+ ions, releasing the stored charge. This reduction process is associated with the release of hydroxide ions. d. Overall Reaction : The overall pseudocapacitance reaction can be summarized as: Charging: Ni 3+ + OH − → Ni 4+ + e − + OH − Discharging: Ni 4+ + e − + OH − → Ni 3+ + OH − The DFT calculations reveal detailed information about the electronic structure, particularly the contributions of the p and d orbitals to the overall DOS. Specifically, the Ni 3d and O 2p orbitals play a significant role in the charge storage mechanism. The density of states (DOS) and partial density of states (PDOS) for the La, Ni, and O atoms in the LaNiO 3 crystal structure, help to understand the pseudocapacitance behavior of LaNiO 3 when used as an electrode material. The PDOS analysis shows significant contributions from Ni 3d and O 2p orbitals around the Fermi level, indicating that these orbitals are actively involved in the electronic conduction and redox reactions, essential for pseudocapacitance. The nature of the La–O bond can be inferred from the PDOS. The lack of significant hybridization between La 5d and O 2p states near the Fermi level indicates a weak La–O covalency bond. This means that the La–O interaction is not contributing to the delocalized electronic states necessary for metallic conduction or redox activity. The weak covalency of the La–O bond implies that La atoms act more as structural stabilizers rather than active participants in charge storage. Conclusion In this investigation, the LaNiO 3 perovskite and LaNiO 3 @AC nanocomposite were successfully fabricated. Both energy storage techniques, like pseudocapacitor and EDLC are involved in LaNiO 3 @AC nanocomposite electrodes. It has outstanding electrochemical performance with long cycle life such as C s of 218.57 F/g at 5 mV/s scan rate, E s of 30.35 W h/kg, P s of 1.58 kW/kg along with 94.57% retention after 3000 cycles, whereas LaNiO 3 perovskite electrode exhibits a C s of 177.53 F/g at 5 mV/s scan rate, E s of 24.65 W h/kg, P s of 1.48 kW/kg and average cyclic stability with 73.35% retention after 3000 cycles, caused the presence of high porous and conductive AC on LaNiO 3 @AC nanocomposite increased the ions contact area coming from electrolyte as well as enhanced the electrical conductivity of the electrode, as a result, improved the overall electrochemical performance. The EIS result even demonstrates that the LaNiO 3 @AC nanocomposite electrode exhibits superior power performance due to its reduced internal resistance (R s and R ct ) in comparison to the LaNiO 3 electrode. Moreover, the LaNiO 3 @AC nanocomposite material has significant advantages due to the low cost and availability of AC, lowering the total cost of the supercapacitor. Dunn's, b-fitting, and Randel Savic models show the storage contribution in the LaNiO 3 @AC nanocomposite electrode yielded better findings than the LaNiO 3 electrode. DFT analysis indicates the structure of LaNiO 3 material is appropriate for significant energy storage and stability. So, considering all aspects, it can be said that the LaNiO 3 @AC nanocomposite electrode is a promising candidate for next-generation supercapacitor electrode applications. Declarations Author Contribution BC- Conceptualization, Methodology, Investigation, Writing - Original Draft, Visualization, Funding acquisition.AS- Formal analysis, Validation, Resources, Data Curation.BK : Software, Investigation, Writing - Review & Editing, Supervision, Project AdministrationAP: Investigation, Writing - Review & EditingDD: Investigation, Writing - Review & Editing,SP: Funding acquisition, Supervision, Writing - Review & Editing.All authors reviewed the manuscript. Acknowledgement The authors gratefully acknowledge Suvamay Pramanik, Presidency University, 86/1 College Street, Kolkata-700073 for assistance with the electrochemical measurements. References Zepeng Bai, Hongji Li, Mingji Li, Cuiping Li, Xufei Wang, Changqing Qu, Baohe Yang, “Flexible carbon nanotubes-MnO2/reduced graphene oxide-polyvinylidene fluoride films for supercapacitor electrodes,” Int J Hydrogen Energy , vol. 40, no. 46, pp. 16306–16315, Dec. 2015, doi: 10.1016/j.ijhydene.2015.09.065. Z. Li, W. 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Lokhande, “Amperometric CO2 gas sensor based on interconnected web-like nanoparticles of La2O3 synthesized by ultrasonic spray pyrolysis,” Microchimica Acta , vol. 184, no. 10, pp. 3713–3720, Oct. 2017, doi: 10.1007/s00604-017-2364-3. L. Wang and X. Y. Qin, “Effect of calcination methods on electrochemical performance of NiO used as electrode materials for supercapacitor,” 2014, doi.org/10.1007/s12034-014-0664-3 X. Qi, W. Zheng, X. Li, and G. He, “Multishelled NiO hollow microspheres for high-performance supercapacitors with ultrahigh energy density and robust cycle life,” Sci Rep , vol. 6, Sep. 2016, doi: 10.1038/srep33241. F. Wang, G. Li, Q. Zhou, J. Zheng, C. Yang, and Q. Wang, “One-step hydrothermal synthesis of sandwich-type NiCo 2 S 4 @reduced graphene oxide composite as active electrode material for supercapacitors,” Appl Surf Sci , vol. 425, pp. 180–187, Dec. 2017, doi: 10.1016/j.apsusc.2017.07.016. A. S. Bondarenko and G. A. Ragoisha, “Variable Mott-Schottky plots acquisition by potentiodynamic electrochemical impedance spectroscopy,” Journal of Solid State Electrochemistry , vol. 9, no. 12, pp. 845–849, Dec. 2005, doi: 10.1007/s10008-005-0025-7. Q. Tang, M. Sun, S. Yu, and G. Wang, “Preparation and supercapacitance performance of manganese oxide nanosheets/graphene/carbon nanotubes ternary composite film,” Electrochim Acta , vol. 125, pp. 488–496, Apr. 2014, doi: 10.1016/j.electacta.2014.01.139. I. Shafi, E. Liang, and B. Li, “Ultrafine chromium oxide (Cr2O3) nanoparticles as a pseudocapacitive electrode material for supercapacitors,” J Alloys Compd , vol. 851, Jan. 2021, doi: 10.1016/j.jallcom.2020.156046. Y. Dong, D. Li, C. Gao, Y. Liu, and J. Zhang, “Supporting information Self-assembled 3D urchin-like Ti 0.8 Sn 0.2 O 2-rGO hybrid nanostructure as anode material for high-rate and long cycle life Li-ion batteries,” 2017, doi.org/10.1039/C7TA01211J O. A. González-Meza, E. R. Larios-Durán, A. Gutiérrez-Becerra, N. Casillas, J. I. Escalante, and M. Bárcena-Soto, “Development of a Randles-Ševčík-like equation to predict the peak current of cyclic voltammetry for solid metal hexacyanoferrates,” Journal of Solid State Electrochemistry , vol. 23, no. 11, pp. 3123–3133, Nov. 2019, doi: 10.1007/s10008-019-04410-6. M. Mačák, P. Vyroubal, T. Kazda, and K. Jaššo, “Numerical investigation of lithium-sulfur batteries by cyclic voltammetry,” J Energy Storage , vol. 27, Feb. 2020, doi: 10.1016/j.est.2019.101158. E. A. Nowadnick, J. P. Ruf, H. Park, P. D. C. King, D. G. Schlom, K. M. Shen, and A. J. Millis, “Quantifying electronic correlation strength in a complex oxide: A combined DMFT and ARPES study of LaNiO3,” Phys Rev B Condens Matter Mater Phys , vol. 92, no. 24, Dec. 2015, doi: 10.1103/PhysRevB.92.245109. X. Liao, V. Singh, and H. Park, “Oxygen vacancy induced site-selective Mott transition in LaNiO3,” Phys Rev B , vol. 103, no. 8, Feb. 2021, doi: 10.1103/PhysRevB.103.085110. Š. Masys, S. Mickevičius, S. Grebinskij, and V. Jonauskas, “Electronic structure of LaNiO3-x thin films studied by x-ray photoelectron spectroscopy and density functional theory,” Phys Rev B Condens Matter Mater Phys , vol. 82, no. 16, Oct. 2010, doi: 10.1103/PhysRevB.82.165120. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4550514","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":319252933,"identity":"f3d923d3-7981-4fc8-9587-76049776c904","order_by":0,"name":"Buddhodev Chowdhury","email":"","orcid":"","institution":"University of Kalyani","correspondingAuthor":false,"prefix":"","firstName":"Buddhodev","middleName":"","lastName":"Chowdhury","suffix":""},{"id":319252936,"identity":"486d09a9-44e1-435e-b607-123b7dc36ed6","order_by":1,"name":"Amrit Sahis","email":"","orcid":"","institution":"Sidho-Kanho-Birsha University","correspondingAuthor":false,"prefix":"","firstName":"Amrit","middleName":"","lastName":"Sahis","suffix":""},{"id":319252937,"identity":"731a610c-0d1f-47f0-add0-68a6ed4cc9a7","order_by":2,"name":"Bibhatsu Kuiri","email":"","orcid":"","institution":"Sidho-Kanho-Birsha University","correspondingAuthor":false,"prefix":"","firstName":"Bibhatsu","middleName":"","lastName":"Kuiri","suffix":""},{"id":319252940,"identity":"868bf3d0-744d-4842-9390-f21aff30c585","order_by":3,"name":"Ardhendu Patra","email":"","orcid":"","institution":"Sidho-Kanho-Birsha University","correspondingAuthor":false,"prefix":"","firstName":"Ardhendu","middleName":"","lastName":"Patra","suffix":""},{"id":319252944,"identity":"0dd5609e-5550-4cda-9d63-ee9f48d84db8","order_by":4,"name":"Debasis Dhak","email":"","orcid":"","institution":"Sidho-Kanho-Birsha University","correspondingAuthor":false,"prefix":"","firstName":"Debasis","middleName":"","lastName":"Dhak","suffix":""},{"id":319252945,"identity":"38f9fd12-da3d-489c-a4d8-e4a9b17bf285","order_by":5,"name":"Sudipta Pal","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIiWNgGAWjYHACgwNAgoefh7kBSEtAxBIIaklgkJHsYSRBC0iFjcEZsBYigPyM5I2HC3/Y8RifOdgmzbvDIrGB/fADhoc78FhxI63g8IyEZB6zs41ALWckEht40gwYEs/g0SKRY3CYJ4GZx+w8I1BLm4QxA0MOA0NiGz6HgbXU8xj3w7Twv8GvheEGWMthHgPeRrAWOQYJArYYnHkG9EvacR6JMwebLecCtbBJPDM4gNdh7cmbPxfYVNvz9yQfvPG2rY6Hnz/54cOf+BwGBMxQmgUcj2xAfAC/BoQW5g+EVI6CUTAKRsHIBAAq7Urom1uEJwAAAABJRU5ErkJggg==","orcid":"","institution":"University of Kalyani","correspondingAuthor":true,"prefix":"","firstName":"Sudipta","middleName":"","lastName":"Pal","suffix":""}],"badges":[],"createdAt":"2024-06-08 12:08:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4550514/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4550514/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":59872095,"identity":"81863f61-32ad-489e-a5af-649cd035ef20","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":638008,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustration of the generation process for the LaNiO\u003csub\u003e3\u003c/sub\u003e, LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite material, and supercapacitor electrode.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/13445a87df99d27fb40576e4.png"},{"id":59872098,"identity":"cfec39de-34e4-4930-8f71-ee0df8373bcb","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":267553,"visible":true,"origin":"","legend":"\u003cp\u003e(a) TGA curve of LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite, (b) FTIR curve of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC electrode material.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/d4ec9f3e24020fad5fabf269.png"},{"id":59872099,"identity":"78e87d95-1f9c-4315-b31b-788f11bfe547","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":790973,"visible":true,"origin":"","legend":"\u003cp\u003eStructural characteristics of LaNiO\u003csub\u003e3 \u003c/sub\u003eperovskite and LaNiO\u003csub\u003e3 \u003c/sub\u003e@AC nanocomposite:\u003cstrong\u003e \u003c/strong\u003e(a) Rietveld analysis of XRD data of LaNiO\u003csub\u003e3\u003c/sub\u003e, (b) XRD pattern of AC sample, (c) Comparison of the XRD pattern of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3 \u003c/sub\u003e@AC nanocomposite\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/091f5c278fd8fbd61392e985.png"},{"id":59873149,"identity":"c99115dd-ea18-46fb-8c94-0698ef2c5fe8","added_by":"auto","created_at":"2024-07-08 17:18:23","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1527118,"visible":true,"origin":"","legend":"\u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e electrode: (a) FESEM image; (b), (c), (d) and (e) EDS mapping of O, Ni, and La respectively; (f) and (g) EDS spectra and corresponding percentage of atom presents of this electrode.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/f75aa3bb3673b081ee908492.png"},{"id":59872096,"identity":"538e1234-4604-4aea-a05c-9bd08647837c","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1799095,"visible":true,"origin":"","legend":"\u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode: (a) FESEM image; (b), (c), (d), (e) and (f) EDS mapping of C, O, Ni, and La respectively; (g) and (h) EDS spectra and corresponding percentage of atom presents of this electrode.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/5f9fc7aed8a78afccf7d9b29.png"},{"id":59872104,"identity":"f6d7de34-4efd-4399-b60f-a37d15494854","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":824365,"visible":true,"origin":"","legend":"\u003cp\u003eXPS curve of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003cstrong\u003e \u003c/strong\u003enanocomposite materials.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/ac2dced028bc4ed19989f2bb.png"},{"id":59873151,"identity":"121a1873-e777-4b98-bce7-9eb6def25f87","added_by":"auto","created_at":"2024-07-08 17:18:23","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":679273,"visible":true,"origin":"","legend":"\u003cp\u003eElectrochemical execution of LaNiO\u003csub\u003e3\u003c/sub\u003e, LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite. (a) CV curve of LaNiO\u003csub\u003e3\u003c/sub\u003e at scan rates from 5 - 100 mV/s; (b) CV curve of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite at scan rates from 5 - 100 mV/s; (c) Specific capacitance comparison of two such electrodes with different scan rates; (d) GCD curve of LaNiO\u003csub\u003e3\u003c/sub\u003e at various current densities; (e) GCD curve of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite at various current densities; (f) Comparison among previous and current electrodes with their energy and power density.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/410161758f2e3572a742e4fb.png"},{"id":59872106,"identity":"f20530b0-c226-4f7d-a06a-28f6c51aafd9","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":315369,"visible":true,"origin":"","legend":"\u003cp\u003e(a)\u003cstrong\u003e \u003c/strong\u003eEIS curve of LaNiO\u003csub\u003e3 \u003c/sub\u003eand\u003csub\u003e \u003c/sub\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes in 3 M KOH electrolyte\u003cstrong\u003e \u003c/strong\u003e(b) Cyclic stability of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/2756319f2f6730bf3cdfae7e.png"},{"id":59872103,"identity":"a3bf1547-e75e-4e54-86ac-fd35676e79dd","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":1518405,"visible":true,"origin":"","legend":"\u003cp\u003e(a-b) b-fitting curve for the differentiation of diffusion and capacitive current contribution of LaNiO\u003csub\u003e3 \u003c/sub\u003eand\u003csub\u003e \u003c/sub\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes; (c-d) i(v)/ν\u003csup\u003e ½\u003c/sup\u003e vs ν\u003csup\u003e ½\u003c/sup\u003e plot to measure the \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e\u003csub\u003e \u003c/sub\u003eand \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e values of LaNiO\u003csub\u003e3 \u003c/sub\u003eand\u003csub\u003e \u003c/sub\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes; (e-f) contribution vs scan rate plot to investigate the change of contribution with scan rate.\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/daaba1f2dd17737a8bc21af4.png"},{"id":59873150,"identity":"c8c263f6-fc43-417b-8e8d-fc6b44a38cab","added_by":"auto","created_at":"2024-07-08 17:18:23","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":241942,"visible":true,"origin":"","legend":"\u003cp\u003ePeak i(V) vs ν\u003csup\u003e ½\u003c/sup\u003e curve of LaNiO\u003csub\u003e3 \u003c/sub\u003eand\u003csub\u003e \u003c/sub\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes.\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/3b09e16c3291bc1c3c72c198.png"},{"id":59872105,"identity":"2b4eebfe-5026-4a61-8f78-6711dcc80e1d","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":211541,"visible":true,"origin":"","legend":"\u003cp\u003eGCD curves for LaNiO\u003csub\u003e3 \u003c/sub\u003eat 3M KOH solution at 1 A/g current density by (a) numerical modeling and (b) experiment.\u003c/p\u003e","description":"","filename":"floatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/3bdeae5e4dfc8de382db2852.png"},{"id":59872108,"identity":"0bf2adc1-924e-4523-aa74-78969f8b7fbe","added_by":"auto","created_at":"2024-07-08 17:10:24","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":624954,"visible":true,"origin":"","legend":"\u003cp\u003eRhombohedral Structure of LaNiO\u003csub\u003e3\u003c/sub\u003e (\u003cem\u003eData retrieved from the Materials Project for LaNiO\u003c/em\u003e\u003csub\u003e\u003cem\u003e3\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e (mp-19339) from database version v2022.10.28.\u003c/em\u003e)\u003c/p\u003e","description":"","filename":"floatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/b7ce43317406308b425a7aac.png"},{"id":59872101,"identity":"cda204b6-6d89-4361-b470-f65d1af5de12","added_by":"auto","created_at":"2024-07-08 17:10:23","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":156817,"visible":true,"origin":"","legend":"\u003cp\u003eDensity of States for LaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"floatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/e55d32982739484bc2dd16cc.png"},{"id":59873152,"identity":"c364954b-301e-4eb9-8437-d71573be9e92","added_by":"auto","created_at":"2024-07-08 17:18:24","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":148332,"visible":true,"origin":"","legend":"\u003cp\u003ePartial Density of States for LaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"floatimage14.png","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/0548a1baff77bf2b00e0e71f.png"},{"id":59873561,"identity":"08322636-21ab-4015-8b65-99837f3288a1","added_by":"auto","created_at":"2024-07-08 17:26:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11995218,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4550514/v1/2b9cf88e-9593-4774-9ae6-b952a906078b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Activated carbon-supported lanthanum nickel oxide (LaNiO3 ) perovskite nanocomposite supercapacitor electrode material exhibiting superior power-density and life cycle","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eContemporary human civilization relies extensively upon fossil fuels as its primary reservoir of energy, yet it is imperative to acknowledge that this energy reservoir is subject to a swift and inexorable decline [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Moreover, those types of energy set free huge amounts of pollution into the environment [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. To resolve this, pollution-free renewable energy sources are required. Additionally, energy storage devices such as electrolytic capacitors or electrochemical batteries [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] are to be employed with them. A supercapacitor exhibits a notable power density (\u0026gt;\u0026thinsp;10 kW/kg), although its energy density remains comparatively lower (5 W h/kg). Addressing this disparity necessitates enhancements within the realm of contemporary energy storage mechanisms [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Otherwise, it has a lot of advantages, such as a long cycle life (\u0026gt;\u0026thinsp;100,000 cycles), fast charging and discharging, a broad range of working temperatures (-40 ℃ to 70 ℃), and low maintenance cost [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNumerous studies have been conducted on transition metal oxides and carbon materials such as NiO nanosheets (C\u003csub\u003es\u003c/sub\u003e 81.67, 3 M KOH aqueous electrolyte, current density 0.5 A/g) [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e thin film (C\u003csub\u003es\u003c/sub\u003e 147 F/g, 1 M KOH aqueous electrolyte, scan rate of 5 mV/s) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], Phosphorus-doped porous carbon (C\u003csub\u003es\u003c/sub\u003e 209 F/g, 6 M KOH aqueous electrolyte, current density of 0.5 A/g [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], C\u003csub\u003es\u003c/sub\u003e 127 F/g, Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e@KBr aqueous electrolyte, current density at 3.8 A/g [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], C\u003csub\u003es\u003c/sub\u003e 220 F/g 2 M KOH aqueous electrolyte, scan rate of 5 mV/s) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], Heteroatom self-doped graphitic carbon electrode (C\u003csub\u003es\u003c/sub\u003e 248 F/g, 6 M KOH electrolyte, current density of 10 A/g) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], further investigated a few composite materials made of carbon and transition metal oxides like MnO\u003csub\u003e2\u003c/sub\u003e/AC (C\u003csub\u003es\u003c/sub\u003e 421.5 F/g, 2 M KOH electrolyte, scan rate 0.5 A/g) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], FeO/AC (C\u003csub\u003es\u003c/sub\u003e 168.5 F/g, 1 M Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, current density of 2 A/g) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], ZnO/AC (C\u003csub\u003es\u003c/sub\u003e 178.2 F/g, 6 M KOH aqueous electrolyte with current density 1 A/cm\u003csup\u003e2\u003c/sup\u003e) [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e/AC (C\u003csub\u003es\u003c/sub\u003e 131 F/g, 6 M KOH aqueous electrolyte, scan rate 5 mV/s) [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], NiO/AC (C\u003csub\u003es\u003c/sub\u003e 107 F/g, 6 M KOH electrolyte, scan rate of 5 mV/s) [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e/rGO (C\u003csub\u003es\u003c/sub\u003e 156.25 F/g, 3 M KOH aqueous electrolyte, 0.1 A/g current density)[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] etc., however, none of these had positive outcomes in every aspect.\u003c/p\u003e \u003cp\u003eThe current topic of research on perovskite materials, that has a lot to explore. The usual formula for perovskite is ABO\u003csub\u003e3\u003c/sub\u003e. This perovskite oxide contains two kinds of cations: an alkaline or rare-earth metal (A) such as La, Sr, Sm, Ce, Nd, Gd, Pr, Tb, Y, a 12-fold coordinated cuboctahedral cage of oxygen lattice, and a transition metal (B) such as Ti, Cr, Mn, Fe, Co Ni, Zn, etc. encompassed octahedrally by the oxygen atom, and O is the oxygen atom [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Nearly all metal oxide electroactive materials primarily undergo cation intercalation for charge storage in supercapacitors through a rapid surface redox mechanism. In contrast, perovskite materials exhibit a distinctive capacity for anion intercalation in energy storage, attributed to their unique ABO\u003csub\u003e3\u003c/sub\u003e structural specificity and oxygen vacancies. Current research endeavors primarily concentrate on synthesizing numerous nanoscale metal oxide materials at the electrode level to augment the electrochemical storage capabilities of these metal oxides. Notable perovskite electrodes that have been reported recently include, a mesoporous LaFeO\u003csub\u003e3\u003c/sub\u003e perovskite electrode that achieved a high C\u003csub\u003es\u003c/sub\u003e of 241.3 F/g at 1 A/g current density, it attained a broad potential window (1.8 V) which may retain capacitance for 92.2% of its life after 5000 cycles. Additionally, it has an impressive energy density and power density of 34 W h /kg and 0.9 kW/kg [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], the LaMnO\u003csub\u003e3\u003c/sub\u003e perovskite obtained C\u003csub\u003es\u003c/sub\u003e of 114.4 mA h/g at 1 A/g [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], intrinsic LaNiO\u003csub\u003e3\u003c/sub\u003e demonstrated the highest C\u003csub\u003es\u003c/sub\u003e of 106.58 F/g, 1 A/g current density in 3 M LiOH [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Moreover, LaNiO\u003csub\u003e3\u003c/sub\u003e retained 98% of its initial capacitance after 500 charge-discharge cycles.\u003c/p\u003e \u003cp\u003eIn this investigation, we produced a nanocomposite by combining 90 wt% of LaNiO\u003csub\u003e3\u003c/sub\u003e with 10 wt% high porous and conducting activated carbon denoted LaNiO\u003csub\u003e3\u003c/sub\u003e@AC to increase the electrical conductivity of supercapacitor electrodes as well as the power and cyclic stability of the supercapacitor also reducing the effective cost. To the best of our knowledge, no research has been reported on the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC as a composite form. This electrode functions as both the energy storage mechanism, such as an electric double layer capacitor (EDLC) for the activated carbon material and a pseudocapacitor for the LaNiO\u003csub\u003e3\u003c/sub\u003e materials. To create the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite, a standard precipitation technique was employed [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. The characteristics of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite material were assessed by TGA, FTIR, XRD, FE-SEM, and XPS. Moreover, LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes effectively showed improved electrochemical performance.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Synthesis of LaNiO\u003csub\u003e3\u003c/sub\u003e Sample\u003c/h2\u003e \u003cp\u003eBy standard preparation, 1.76 gm lanthanum nitrate hexahydrate [La(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e, 6 H\u003csub\u003e2\u003c/sub\u003eO] (Merck, India, 99.9% pure) and 1.179 gm nickel nitrate hexahydrate [Ni(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, 6 H\u003csub\u003e2\u003c/sub\u003eO] (Merck, India, 99.9% pure) dissolved in 25 ml of N, N-dimethylformamide (DMF) (Merck, India, 99.8% pure) and stirred for 2 hours. Then 0.45 gm of polyvinylpyrrolidone K-30 (Merck, India, 99% pure) was added to the solution and stirred for 1 hour, then it was kept at boiling temperature with continuous stirring until a gel formed [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Then the prepared gel was kept in a crucible and placed in an oven at 200 ℃ for drying and the dried sample was placed in a muffle furnace for calcination at 600 ℃ for 3 h at the heating rate of 4 ℃/min in an air atmosphere.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Synthesis of AC and LaNiO\u003csub\u003e3\u003c/sub\u003e nanocomposite materials\u003c/h2\u003e \u003cp\u003eSimultaneously stirred and ultrasonicated activated carbon (Alfa Aesar, VA, USA, 99.5% pure) and lanthanum nickel oxide (LaNiO\u003csub\u003e3\u003c/sub\u003e) individually kept in N-methyl-2-pyrrolidone (NMP) medium (Merck, 99.5% pure) until dispersed well. Then, 10 wt% of AC and 90 wt% LaNiO\u003csub\u003e3\u003c/sub\u003e were collected from the solvent and mixed through the ultrasonicated keeping 20 ml of NMP solvent for 2 hours. Further, LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite was collected by filtration process [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e], [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Fabrication of working electrodes\u003c/h2\u003e \u003cp\u003eFor preparing the working electrode, a mixture of 80 wt% of active materials, 10 wt% of PVDF (Sigma Aldrich) binder, and 10 wt% of acetylene black (Alfa Aesar, VA, USA, 99.9% pure) in NMP. Once thoroughly mixed, it was coated on a nickel foam substrate (0.8 cm \u0026times; 0.8 cm) which was cleaned with 3 M HCl and distilled water. The amount of total electrode material was 28 mg/cm\u003csup\u003e2\u003c/sup\u003e. The electrode was heated in an oven at 80 ℃ overnight to eliminate the NMP solvent. After this, compression was enacted utilizing a hydraulic pressure of 10 MPa. A supercapacitor cell was assembled employing two indistinguishable electrodes while interposing a separator akin to filter paper amid the aforementioned electrodes, preparatory to undertaking measurements [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. The whole procedure is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Characterization\u003c/h2\u003e \u003cp\u003eTGA analysis (USA, Perkin-Elmer, STA 6000) was used to determine the material's thermal stability by gradually increasing temperature by 2\u0026deg;C /min, starting from 50\u0026deg;C to 800\u0026deg;C, The crystalline structure of the material was investigated by using X-ray diffractometer (XRD) (Rigaku, Smart Lab) with Cu-K\u003csub\u003eα\u003c/sub\u003e radiation (λ\u0026thinsp;=\u0026thinsp;1.54056 \u0026Aring;) at room temperature and the angle of the collecting data starting from 10\u0026deg; to 80\u0026deg; with a scan rate of 4\u0026deg;/min., the surface morphology of the sample was examined by using field-emission scanning electron microscope (FESEM) (Jeol, JSM-IT300HR, Japan) fitted with a dispersed energy x-ray (EDX). To confirm the prepared nanocomposite electrode materials, the Fourier Transform Infrared Spectroscopy (FTIR) (Perkin-Elmer L120-00A, FT-IR spectrometer, IR spectra) instrument was used at a range of wavenumber from 450\u0026ndash;4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e keeping the sample in KBr pellets and X-ray photoelectron spectroscopy (XPS) (JPS \u0026minus;\u0026thinsp;9030, Jeol, Japan) using an Al-K\u003csub\u003eα\u003c/sub\u003e source was utilized to assess the material's surface elemental makeup and ascertain the elements binding status.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Electrochemical measurement\u003c/h2\u003e \u003cp\u003eAll electrochemical measurements were performed by using cyclic voltammetry with the two-electrode system using 3 M KOH as a potent aqueous electrolyte to facilitate charge transfer with complete dissociation into K\u003csup\u003e+\u003c/sup\u003e and OH\u003csup\u003e\u0026minus;\u003c/sup\u003e ions in aqueous solution, operated at CHI660E electrochemical workstation at room temperature. Cyclic voltammetry (CV) and galvanometric charge discharging (GCD) measurements of supercapacitors were carried out with a potential window range of -1 to 1 V. The electrochemical impedance spectroscopies (EIS) of supercapacitors were taken within 0.01 Hz and 100 kHz. The C\u003csub\u003es\u003c/sub\u003e value of a single electrode was measured by cyclic voltammetry from Eq.\u0026nbsp;(1) and galvanometric charge discharging was measured from Eq.\u0026nbsp;(2). The energy density (\u003cem\u003eE\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e) (W h/kg), and power density (\u003cem\u003eP\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e) (kW/kg) of supercapacitor cells were measured by equations (3) and (4) [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$${C}_{S}=\\left[\\frac{1}{\\nu \\varDelta V}\\underset{{V}_{1}}{\\overset{{V}_{2}}{\\int }}{I}_{1}\\left(V\\right)dV\\right]\\times \\frac{4}{m} \\left(1\\right)$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$${ C}_{S}=\\frac{{I}_{2}\\varDelta t}{\\varDelta V} \\times \\frac{4}{m} \\left(2\\right)$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$${E}_{s}=\\frac{1}{8}{C}_{s}({\\varDelta V)}^{2}\\times \\frac{1}{3.6} (3)$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equd\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equd\" name=\"EquationSource\"\u003e\n$${P}_{s}=\\frac{{E}_{s}}{\\varDelta t} \\times 3.6 \\left(4\\right)$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cem\u003em\u003c/em\u003e is the total mass of two electrode materials, \u003cem\u003eυ\u003c/em\u003e (V/s) denotes scan rate, \u003cem\u003e∆V\u003c/em\u003e (V) denotes potential window, \u003cem\u003eI\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e (A) is the voltammetric current, \u003cem\u003eI\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e (A) is discharge current, and \u003cem\u003e∆t\u003c/em\u003e (s) denotes discharging time.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec9\"\u003e\n \u003ch2\u003e3.1. Characterization of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite\u003c/h2\u003e\n \u003cdiv id=\"Sec10\"\u003e\n \u003ch2\u003e3.1.1. Thermal analysis\u003c/h2\u003e\n \u003cp\u003eThermogravimetric analysis (TGA) of the prepared gel after heating at 180 ℃ (before calcination) is executed under a nitrogen gas flow rate of 20 ml/min and with a temperature range of 30 ℃ to 800 ℃ for assessing the thermal stability shown in Fig.\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e (a). The first phase weight loss of LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite was started from 180°C to 295°C at a slow rate, and this weight loss (3.5 wt%) was due to the decomposition of a small amount of organic DMF solvent into various byproducts like CO\u003csub\u003e2\u003c/sub\u003e, H\u003csub\u003e2\u003c/sub\u003eO (g), etc. The second phase of weight loss (40.85 wt%) has a sharp peak and lasts from temperatures above 295°C to almost 585°C due to the degradation of PVP-K-30. In the third phase, which lasted from 580°C to 800°C, there was no weight loss observed which means in this temperature range only the LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite material existed. [\u003cspan\u003e2\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003e3.1.2. FTIR spectroscopy\u003c/h2\u003e\n \u003cp\u003eThe FTIR spectroscopy was used to distinguish the functional groups in the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite in Fig.\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e (b). A broad peak was found at 3436.35 cm\u003csup\u003e− 1\u003c/sup\u003e which indicates stretching vibrations of the O–H bond due to moisture. The peak at 2937.31 cm\u003csup\u003e− 1\u003c/sup\u003e represented the existence of C-H stretch, and another peak near it at 2882.10 cm\u003csup\u003e− 1\u003c/sup\u003e was due to C-H\u003csub\u003e2\u003c/sub\u003e symmetric stretching. The peak at 1667.89 cm\u003csup\u003e− 1\u003c/sup\u003e may be due to the C = O stretching vibration The peaks at 1505.88 cm\u003csup\u003e− 1\u003c/sup\u003e and 1446.75 cm\u003csup\u003e− 1\u003c/sup\u003e are caused by the aromatic functional group's C-C stretching vibration. The peak at 1405.94 cm\u003csup\u003e− 1\u003c/sup\u003e may be due to the stretching vibration of the C = O bond. Also, some weak bands were found between 1114.44 cm\u003csup\u003e− 1\u003c/sup\u003e − 1302.67 cm\u003csup\u003e− 1\u003c/sup\u003e which may be due to the existence of C-O groups. The peak at 658.22 cm\u003csup\u003e− 1\u003c/sup\u003e could be caused by an alkene's C = C stretching vibration. The La-O and Ni-O metal oxides detected in the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite are shown by the peaks located at 566.33 cm\u003csup\u003e− 1\u003c/sup\u003e and 472.62 cm\u003csup\u003e− 1\u003c/sup\u003e, respectively [\u003cspan\u003e42\u003c/span\u003e], [\u003cspan\u003e43\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\"\u003e\n \u003ch2\u003e3.1.3. XRD analysis\u003c/h2\u003e\n \u003cp\u003eXRD was employed to ascertain the crystalline structure or composition of a sample. Distinct peaks corresponding to the desired materials were assured about the absence of any impurities of the materials. The synthesized process of two-dimensional perovskite LaNiO\u003csub\u003e3\u003c/sub\u003e was represented in Fig.\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e. In this experiment La and Ni ions coming from their respective nitrate salt quickly react with the precursor N, N-dimethylformamide (DMF) to form the perovskite structure under the presence of polyvinylpyrrolidone K-30 for assistance to minimize the size of the particle at the nanoscale. Prepared LaNiO\u003csub\u003e3\u003c/sub\u003e initially is an amorphous structure and after heating with high temperature converted 2D perovskite crystal structure [\u003cspan\u003e2\u003c/span\u003e]. The structural information of the prepared LaNiO\u003csub\u003e3\u003c/sub\u003e sample was known by X-ray diffraction. Figure\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e (a) indicates the XRD patterns of the sample showing broad and weak peak shapes[\u003cspan\u003e37\u003c/span\u003e], [\u003cspan\u003e44\u003c/span\u003e], [\u003cspan\u003e45\u003c/span\u003e], [\u003cspan\u003e46\u003c/span\u003e], [\u003cspan\u003e47\u003c/span\u003e]. Grain size of nanocrystalline materials was measured by the Eq.\u0026nbsp;(5).\u003c/p\u003e\n \u003cdiv id=\"Eque\"\u003e\n \u003cdiv id=\"FileID_Eque\" name=\"EquationSource\"\u003e$$D =\\frac{K\\lambda }{\\beta cos\\theta } \\left(5\\right)$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere D, K, λ, β, and θ are the average grain size, constant (usually set as at 0.9), wavelength (Cu-K\u003csub\u003eα\u003c/sub\u003e) valued at 1.54056 Å, the full width at half maximum intensity, and Bragg’s angle in degree, respectively.\u003c/p\u003e\n \u003cp\u003eThe average grain size of the prepared LaNiO\u003csub\u003e3\u003c/sub\u003e sample was 16.40 nm which was approximately the same as pure LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite material with a rhombohedral structure with the cell parameters (a = 5.460511 Å, b = 5.460511 Å, c = 13.139636 Å; α = 90°, β = 90°, γ = 120°) and R-3c space group. The result proved that the sample was successfully generated and performed best when heated to 600°C for 3 hours, out of all the different heating temperatures and times [\u003cspan\u003e2\u003c/span\u003e], [\u003cspan\u003e47\u003c/span\u003e]. The sample's sharp diffraction peak intensity was discovered, indicating that under these circumstances, a high crystalline structure had formed in the sample. Figure\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e (b) represents the XRD graph of the AC sample. XRD patterns of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite were found to be the same as the mentioned LaNiO\u003csub\u003e3\u003c/sub\u003e patterns that could be AC layers were completely immersed by the LaNiO\u003csub\u003e3\u003c/sub\u003e layers and, the peaks of AC were not separately found as shown in Fig.\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e (c).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec13\"\u003e\n \u003ch2\u003e3.1.4. SEM images\u003c/h2\u003e\n \u003cp\u003eThe scanning electron micrograph shows the high porosity as observed in Fig.\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e. The black spots indicate the porosity of the LaNiO\u003csub\u003e3\u003c/sub\u003e material. There are certain channels also observed, as indicated by the large black areas in Fig.\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e (a) [\u003cspan\u003e48\u003c/span\u003e]. Figure\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e (b) shows the X-ray mapping of all the elements O, Ni, and La together, indicating the homogeneous distribution of elements, which is also clearly visible from the X-ray mapping of the individual elements as shown in Fig.\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e (c), (d), and (e), respectively, for O, Ni, and La, the EDS analysis data of LaNiO\u003csub\u003e3\u003c/sub\u003e material are represented in Fig.\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e (f) and (g), where the element percentages present ratio are shown as O: Ni: La = 52.45: 12.95: 12.24, which are very close to the formula ratio. There is 22.37% carbon in the material, which is due to the addition of carbon black for the preparation of electrodes. Figure\u0026nbsp;\u003cspan\u003e5\u003c/span\u003e shows that the surface area of the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite material has increased due to its high porosity and small pore size compared to the LaNiO\u003csub\u003e3\u003c/sub\u003e material. Figure\u0026nbsp;\u003cspan\u003e5\u003c/span\u003e (b) represents the X-ray mapping of the whole elements present in the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC as C, O, Ni, and La altogether, thus beginning the homogeneous distribution of elements, which is also clearly visible from the X-ray mapping of the individual elements as shown in Fig.\u0026nbsp;\u003cspan\u003e5\u003c/span\u003e (c), (d), (e), and (f), respectively, for C, O, Ni, and La. The element percentages present in the EDS analysis data of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite material are shown in Fig.\u0026nbsp;\u003cspan\u003e5\u003c/span\u003e (g) and (h), with C: O: Ni: La = 61.84: 30.08: 4.03: 4.05. Here, the ratio of carbon and oxygen atoms is greater than their formula ratio, which indicates the presence of carbon black, and some oxygen atoms react with carbon atoms.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec14\"\u003e\n \u003ch2\u003e3.1.5. XPS analysis\u003c/h2\u003e\n \u003cp\u003eThe XPS analysis of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite materials is shown in Fig.\u0026nbsp;\u003cspan\u003e6\u003c/span\u003e (a). The characteristic peak of La is indicated at 853.64 eV and 840.78 eV, which are for La 3d\u003csub\u003e3/2\u003c/sub\u003e and La 3d\u003csub\u003e5/2\u003c/sub\u003e, respectively. These peaks are coming for the La\u003csup\u003e3+\u003c/sup\u003e of perovskite LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite materials, its La 3d\u003csub\u003e5/2\u003c/sub\u003e peak disassociation ΔE\u003csub\u003e1\u003c/sub\u003e = 3.9 eV, spin-orbit splitting energy is ΔE\u003csub\u003e2\u003c/sub\u003e = 16.9 eV for the La 3d doublet as shown in Fig.\u0026nbsp;\u003cspan\u003e6\u003c/span\u003e (b) [\u003cspan\u003e49\u003c/span\u003e], [\u003cspan\u003e50\u003c/span\u003e], [\u003cspan\u003e51\u003c/span\u003e]. The peaks of Ni are shown at 874.55 eV and 857.80 eV due to Ni 2p\u003csub\u003e1/2\u003c/sub\u003e and Ni 2p\u003csub\u003e3/2\u003c/sub\u003e, respectively, and these peaks appear due to the presence of Ni\u003csup\u003e3+\u003c/sup\u003e and Ni\u003csup\u003e2+\u003c/sup\u003e in the perovskite LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite materials as mentioned in Fig.\u0026nbsp;\u003cspan\u003e6\u003c/span\u003e (b). A lower binding energy peak appeared at 532.03 eV, due to the presence of the O\u003csup\u003e2−\u003c/sup\u003e anion in lanthanum oxides (La-O bond), and a higher binding energy peak at 533.67 eV displays the presence of the O\u003csup\u003e2−\u003c/sup\u003e anion in nickel oxides (Ni-O bond), shows in Fig.\u0026nbsp;\u003cspan\u003e6\u003c/span\u003e (c) [\u003cspan\u003e52\u003c/span\u003e]. The completely oxidized nickel ion (Ni\u003csup\u003e3+\u003c/sup\u003e) in LaNiO\u003csub\u003e3\u003c/sub\u003e material indicates a slightly distorted rhombohedral-like perovskite cell is formed, and both ionic (Ni-O-Ni) and covalent (La-O, Ni-O) chemical bonds are present among them. Another peak has been seen at 285.11 eV on the graph of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite materials in Fig.\u0026nbsp;\u003cspan\u003e6\u003c/span\u003e (d), and it occurs due to the presence of activated carbon (C 1s). All these peaks obliquely prove the perovskite LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite materials are successfully generated.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\"\u003e\n \u003ch2\u003e3.2. Electrochemical behaviors of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite\u003c/h2\u003e\n \u003cp\u003eThe electrochemical execution of prepared electrodes, such as LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite, was observed with the help of cyclic voltammetry (CV), galvanometric charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements with operating voltage range of -1.0 to 1.0 volt. All the measurements have been done in a two-electrode system at room temperature by making a simple supercapacitor cell by using a 3 M KOH electrolyte solution [\u003cspan\u003e2\u003c/span\u003e], [\u003cspan\u003e3\u003c/span\u003e], [\u003cspan\u003e37\u003c/span\u003e]. Firstly, the CV of LaNiO\u003csub\u003e3\u003c/sub\u003e along with LaNiO\u003csub\u003e3\u003c/sub\u003e@AC was performed at several scan rates, such as 5–100 mV/s which is plotted in Fig.\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (a) and (b). Figure\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (a) and (b) show that the area covered by the CV curve was different using different scan rates in a proportional relationship, and the capacitance of the supercapacitor was increasing with decreasing scan rates. The maximum capacitance values of 177.53 F/g and 218.57 F/g were observed at a 5 mV/s scan rate as shown in Fig.\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (a) and (b) respectively for LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC. The specific capacitance of both electrodes at all scan rates is mentioned in Table\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e. It should have a higher capacitance value when the scan rate is below 5 mV/s. The comparison of specific capacitance with scan rates for each electrode is displayed in Fig.\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (c). The LaNiO\u003csub\u003e3\u003c/sub\u003e@AC electrode shows a higher capacitance value than the pure LaNiO\u003csub\u003e3\u003c/sub\u003e electrode due to the presence of conductive high porous AC that increases the transport speed of charges within the electrolyte and its larger surface area helps to store comparatively higher charges as well as enhances the capacitance of the electrodes. The LaNiO\u003csub\u003e3\u003c/sub\u003e electrode exhibits distinct oxidation and reduction peaks, indicating the oxidation-reduction reaction occurred here, and it stores electrical energy due to its pseudo-capacitive nature, whereas in CV curve of the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode has an almost rectangular shape, indicating an accurate electrochemical nature. This is due to activated carbon, which improves overall supercapacitor behavior [\u003cspan\u003e28\u003c/span\u003e]. The previous report showed that LaNiO\u003csub\u003e3\u003c/sub\u003e exhibited a capacitance value of 106.58 F/g at a current density of 1 A/g while 3 M LiOH was taken as an electrolyte. Comparative data are given in Table\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e for the relevant materials such as NiO, La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, NiO/AC, La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e/rGO, etc. which confirmed the higher values in the present study in comparison to the reported values.\u003c/p\u003e\n \u003cp\u003eThe galvanostatic charge-discharge method is a reliable way to find the capacitance of a produced device in poorly controlled conditions. Figure\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (d) and (e) display the GCD curve of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes respectively. A working voltage of between − 1.0 and 1.0 volts was used during the GCD process of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes. Each electrode has an almost linear discharge profile, suggesting a triangle shape similar to a capacitive type. A quick potential drop was observed during the discharging process due to the ohmic loss across the supercapacitor device's internal resistance (IR), also known as the equivalent series resistance (ESR). The GCD measurements determined the specific capacitance of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite at 0.5 A/g current density to be 152.68 F/g and in the case of the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode, the specific capacitance is 99.75 F/g at 0.5 A/g current density using Eq.\u0026nbsp;(2), as shown in Fig.\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (d) and (e).\u003c/p\u003e\n \u003cp\u003eEquations\u0026nbsp;(3) and (4) were used to measure the energy and power density, and the computed value is shown in Fig.\u0026nbsp;\u003cspan\u003e7\u003c/span\u003e (f). Here, attempt to compare the energy and power density of the current and prior electrodes. According to the current investigation, the LaNiO\u003csub\u003e3\u003c/sub\u003e cell's energy density and power density were 24.65 W h/kg and 1.48 kW/kg, respectively, while the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite cell's values were 30.35 W h/kg and 1.58 kW/kg as listed in Table\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e, which put it in a better position than the other electrodes.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 1\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eComparison of measured specific capacitance values among LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite from CV and GCD measurements.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eC\u003csub\u003es\u003c/sub\u003e (F/g) from CV measurement\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eC\u003csub\u003es\u003c/sub\u003e (F/g), E\u003csub\u003es\u003c/sub\u003e (W h/kg), and P\u003csub\u003es\u003c/sub\u003e (kW/kg) from GCD measurement\u003c/p\u003e\n \u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eScan rate (mV/s)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCurrent density (A/g)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eE\u003csub\u003es\u003c/sub\u003e (W h/kg)\u003c/p\u003e\n \u003cp\u003e\u0026amp; P\u003csub\u003es\u003c/sub\u003e (kW/kg)\u003c/p\u003e\n \u003cp\u003eof LaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eE\u003csub\u003es\u003c/sub\u003e (W h/kg)\u003c/p\u003e\n \u003cp\u003e\u0026amp; P\u003csub\u003es\u003c/sub\u003e (kW/kg)\u003c/p\u003e\n \u003cp\u003eof LaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eE\u003csub\u003es\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(W h/kg)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003es\u003c/sub\u003e (kW/kg)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eE\u003csub\u003es\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(W h/kg)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003es\u003c/sub\u003e (kW/kg)\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e177.53\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e218.57\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e99.75\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e152.68\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e24.65\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1.48\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e30.35\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1.58\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e152.44\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e184.92\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e70.33\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e122.10\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e21.17\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3.39\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e25.68\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e2.41\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e119.52\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e132.68\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e67.18\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e112.54\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e16.60\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3.71\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e18.43\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3.42\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e102.13\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e105.40\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1.25\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e57.88\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e69.86\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e14.18\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e4.60\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e14.64\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e4.25\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e92.66\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e95.23\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e45.15\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e25.80\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e12.86\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5.40\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e13.23\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5.56\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e84.50\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e88.57\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1.75\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e43.72\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e13.74\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e11.74\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e6.63\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e12.30\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e6.34\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eBriefly represented the capacitance values of some metal oxides and metal oxide-activated carbon composites in previous publications.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eElectrode materials\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eElectrolyte\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eCurrent density/ scan rate\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eSpecific capacitance\u003c/p\u003e\n \u003cp\u003e(F/g)\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eCapacitance retention\u003c/p\u003e\n \u003cp\u003e(in cycles)\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\"\u003e\n \u003cp\u003eRef.\u003c/p\u003e\n \u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eNiO nanosheet\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5 A/g\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e81.67\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e78.5% after 3000\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[\u003cspan\u003e19\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eLa\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e thin film\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5 mV/s\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e147\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e96% after 2000\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[\u003cspan\u003e20\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eNiO/AC\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e6 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5 mV/s\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e166⋅8\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e92.6 after 800\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[\u003cspan\u003e29\u003c/span\u003e], [\u003cspan\u003e53\u003c/span\u003e], [\u003cspan\u003e54\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eLa\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e/ rGO\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e0.1 A/g\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e156.25\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e78% after 500\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[\u003cspan\u003e30\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3 M LiOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e1 A/g\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e106.58\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e98% after 500\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[\u003cspan\u003e34\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5 mV/s\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e177.53\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e73.35% after 3000\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[Present work]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e3 M KOH\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5 mV/s\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e218.57\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e94.57% after 3000\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e[Present work]\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eElectrochemical impedance spectroscopy (EIS) was used for studying the internal resistance and electrochemical kinetics of the above-mentioned electrodes. The acquired Nyquist plots of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC electrodes are displayed in Fig.\u0026nbsp;\u003cspan\u003e8\u003c/span\u003e (a) [\u003cspan\u003e2\u003c/span\u003e], [\u003cspan\u003e44\u003c/span\u003e], [\u003cspan\u003e55\u003c/span\u003e]. An EIS spectrum analyser software was utilized to fit and simulate the EIS spectra and the corresponding circuit schematic is displayed in Fig.\u0026nbsp;\u003cspan\u003e8\u003c/span\u003e (a) (inset) [\u003cspan\u003e56\u003c/span\u003e]. The Nyquist plots are accessed by plotting the imaginary part versus the real part of the impedance with a frequency range of 0.01 Hz to 100 kHz. An intersection observed at the high-frequency region with the real axis causes the electrode-electrolyte interface resistance known as electrolyte resistance (R\u003csub\u003es\u003c/sub\u003e) which is connected through the series combination of electron charge transfer resistance (R\u003csub\u003ect\u003c/sub\u003e) at the interface of the electrode and electrolyte which is measured by the diameter of the semi-circle appeared on Z′ axis as shown in 8 (a), Warburg impedance (Z\u003csub\u003ew\u003c/sub\u003e) due to consideration the diffusion of ions stored at the electrode-electrolyte contact, and EDLC (C\u003csub\u003edl\u003c/sub\u003e) [\u003cspan\u003e40\u003c/span\u003e]. Furthermore, it incorporates an additional series circuit with a Faradaic capacitance (C\u003csub\u003ef\u003c/sub\u003e) as well as the resistance (R\u003csub\u003e1\u003c/sub\u003e) at the electrode contacts [\u003cspan\u003e1\u003c/span\u003e]. The vertical line in the comparatively low-frequency region represents the perfect capacitive properties. The electrolyte resistance (R\u003csub\u003es\u003c/sub\u003e) and charge transfer resistance (R\u003csub\u003ect\u003c/sub\u003e) values of LaNiO\u003csub\u003e3\u003c/sub\u003e are 0.960 Ω and 0.865 Ω respectively. Whereas, the values of R\u003csub\u003es\u003c/sub\u003e and R\u003csub\u003ect\u003c/sub\u003e of LaNiO\u003csub\u003e3\u003c/sub\u003e@AC are 0.066 Ω and 0.592 Ω respectively as seen in the EIS curve. It has been shown that the total internal resistance of the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode is lower than the LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite electrode due to the presence of high porous and conductive AC on LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite [\u003cspan\u003e57\u003c/span\u003e]. Concerning actual supercapacitor applications, LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode exhibits excellent electrical conductivity with a higher R\u003csub\u003ect\u003c/sub\u003e value than LaNiO\u003csub\u003e3\u003c/sub\u003e.\u003c/p\u003e\n \u003cp\u003eAdditionally, the electrochemical stability was computed using CV data from the first and subsequent 3000 CV cycles, as shown in Fig.\u0026nbsp;\u003cspan\u003e8\u003c/span\u003e (b). The LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite supercapacitor electrode performed remarkable cyclic stability; the retention was 94.57% of the initial capacitance after 3000 cycles at 100 mV/s. The reason for the remarkable cyclic stability may be due to the presence of AC networks executing as an electrical double layer capacitor (EDLC), whereas LaNiO\u003csub\u003e3\u003c/sub\u003e retained 73.35% of its initial capacitance after 3000 cycles at 100 mV/s. While contrasting every electrode listed in Table\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e, the cyclic stability of The LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode outperformed all other electrodes, including the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode, this is the essential feature for the electrochemical performance of a supercapacitor.\u003c/p\u003e\n \u003cp\u003eAdditionally, it was shown that a supercapacitor retains total charge through both capacitive and diffusive controlled contributions. This charge contribution is quantified in a specific fixed potential using the following Dunn's equation [\u003cspan\u003e58\u003c/span\u003e].\u003c/p\u003e\n \u003cdiv id=\"Equf\"\u003e\n \u003cdiv id=\"FileID_Equf\" name=\"EquationSource\"\u003e$$i = a{\\nu }^{b} \\left(6\\right)$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003ewhere ν stands for scan rate, \u003cem\u003ea\u003c/em\u003e and \u003cem\u003eb\u003c/em\u003e are the modified parameters, and \u003cem\u003ei\u003c/em\u003e is the voltammogram peak current. The value of \u003cem\u003eb\u003c/em\u003e is measured by the slope of a curve plotting through log \u003cem\u003ei\u003c/em\u003e vs log \u003cem\u003eν\u003c/em\u003e, which lies between 0.5 ≤ \u003cem\u003eb\u003c/em\u003e ≤ 1. When \u003cem\u003eb\u003c/em\u003e is close to 0.5, it indicates a diffusive regulated charge storage contribution; in this instance, the current is proportionate to \u003cem\u003eν\u003c/em\u003e \u003csup\u003e1/2\u003c/sup\u003e, conversely, \u003cem\u003eb\u003c/em\u003e value near 1 represents a capacitive charge storage contribution, and the corresponding current is proportionate to \u003cem\u003eν\u003c/em\u003e, at a scan rate of 5 mV/s, the current experimental value of \u003cem\u003eb\u003c/em\u003e, which employed in the assessment whole types of capacity for charge storage. The values of \u003cem\u003eb\u003c/em\u003e are calculated for the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode at 0.589 and for the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode at 0.595 as shown in Fig.\u0026nbsp;\u003cspan\u003e9\u003c/span\u003e (a-b), indicates both the electrodes have diffusive and capacitive storage contribution and the higher \u003cem\u003eb\u003c/em\u003e value of the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode compared to the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode signifies an increase in capacitive charge storage contribution and improved performance [\u003cspan\u003e59\u003c/span\u003e]. Dunn's equation may also be used to compute charge storage via capacitance and diffusion is given below\u003c/p\u003e\n \u003cdiv id=\"Equ1\"\u003e\n \u003cdiv id=\"FileID_Equ1\" name=\"EquationSource\"\u003e$$i\\left(V\\right)={K}_{1}\\upsilon + {K}_{2}{\\upsilon }^{1/2}$$\u003c/div\u003e\n \u003cdiv\u003e7\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eor\u003c/p\u003e\n \u003cdiv id=\"Equg\"\u003e\n \u003cdiv id=\"FileID_Equg\" name=\"EquationSource\"\u003e$$\\frac{i\\left(V\\right)}{{\\upsilon }^{1/2}}= {K}_{1}{\\upsilon }^{1/2}+{K}_{2}\\upsilon \\left(8\\right)$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere \"\u003cem\u003eν\u003c/em\u003e\" stands for the modified scan rate and \u003cem\u003eK\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e\u003cem\u003eν\u003c/em\u003e and \u003cem\u003eK\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e \u003cem\u003eν\u003c/em\u003e\u003csup\u003e1/2\u003c/sup\u003e reflect the contributions made by the capacitive and diffusion-controlled charge storage systems at this time, respectively. Utilizing Eq.\u0026nbsp;(8), the graph \u003cem\u003ei(v)/ v\u003c/em\u003e\u003csup\u003e1/2\u003c/sup\u003e against \u003cem\u003eν\u003c/em\u003e\u003csup\u003e1/2\u003c/sup\u003e is plotted to get the values of \u003cem\u003eK\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e and \u003cem\u003eK\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e, where \u003cem\u003eK\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e represents the curve's slope and \u003cem\u003eK\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e is the y-intercept. At a scan rate of 5 mV/s, the \u003cem\u003eK\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e and \u003cem\u003eK\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e values for the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode are 0.0000056 and 0.0001, respectively, whereas, for the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode 0.0000104 and 0.000134 as shown in Fig.\u0026nbsp;\u003cspan\u003e9\u003c/span\u003e (c-d), and the corresponding capacitance and diffusion-controlled charge storage of LaNiO\u003csub\u003e3\u003c/sub\u003e and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode are 12.28%, 87.72% and 14.82%,85.18%, respectively. The values of capacitance and diffusion-controlled charge storage of all scan rates from 5–100 mV/s are listed in Table\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e. This observation indicates that the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode performs better electrochemically than the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode as it has a higher capacitive charge storage value, and Fig.\u0026nbsp;\u003cspan\u003e9\u003c/span\u003e (e-f) displays the value of the capacitive charge storage contribution rises in proportion to scan rates causing a higher scan rate accelerated the capacitive contribution charge storage process.\u003c/p\u003e\n \u003cdiv id=\"Equh\"\u003e\n \u003cdiv id=\"FileID_Equh\" name=\"EquationSource\"\u003e$${i}_{peak}=0.4463 n FA{C}_{o}{\\left(\\frac{nFD}{RT}\\upsilon \\right)}^{1/2} \\left(9\\right)$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere \u003cem\u003ei\u003c/em\u003e\u003csub\u003epeak\u003c/sub\u003e denotes the peak current of the voltammogram, \u003cem\u003en\u003c/em\u003e stands for the number of electrons exchanged during the electrode reaction, \u003cem\u003eF\u003c/em\u003e stands for the Faraday constant, \u003cem\u003eA\u003c/em\u003e for electrode surface area, \u003cem\u003eC\u003c/em\u003e\u003csub\u003e\u003cem\u003eo\u003c/em\u003e\u003c/sub\u003e for electrode material surface concentration, \u003cem\u003eD\u003c/em\u003e for chemical diffusion coefficient, \u003cem\u003eυ\u003c/em\u003e for scan rate, \u003cem\u003eR\u003c/em\u003e for molar gas constant, and \u003cem\u003eT\u003c/em\u003e for temperature [\u003cspan\u003e60\u003c/span\u003e].\u003c/p\u003e\n \u003cp\u003eWhen \u003cem\u003ei\u003c/em\u003e\u003csub\u003epeak\u003c/sub\u003e is plotted against \u003cem\u003eν\u003c/em\u003e\u003csup\u003e1/2\u003c/sup\u003e, a linear curve with a slope of {0.4463 n \u003cem\u003eFAC\u003c/em\u003e\u003csub\u003e\u003cem\u003eo\u003c/em\u003e\u003c/sub\u003e \u003cem\u003e(nFD/RT)\u003c/em\u003e\u003csup\u003e1/2\u003c/sup\u003e} and zero intercepts on the y-axis is produced. In contrast, the slope allows for the measurement of D. The results of the current experiment demonstrate that, under identical conditions, the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode's D values are (0.0075) higher than those of the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode (0.0053) as shown in Fig.\u0026nbsp;\u003cspan\u003e10\u003c/span\u003e, suggesting that the former performs better than the latter.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\n \u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e@AC\u003c/p\u003e\n \u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eScan rate (mV/s)\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eCapacitive\u003c/p\u003e\n \u003cp\u003econtribution\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eDiffusive\u003c/p\u003e\n \u003cp\u003econtribution\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eCapacitive\u003c/p\u003e\n \u003cp\u003econtribution\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003eDiffusive\u003c/p\u003e\n \u003cp\u003econtribution\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e12.28\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e87.72\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e14.82\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e85.18\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e15.13\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e84.87\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e19.73\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e80.27\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e21.87\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e78.13\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e27.95\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e72.05\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e28.57\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e71.43\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e35.61\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e64.39\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e33.60\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e66.40\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e40.20\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e59.79\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e37.33\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e62.66\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e45.81\u003c/p\u003e\n \u003c/td\u003e\u003ctd align=\"left\"\u003e\n \u003cp\u003e54.19\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eFigure\u0026nbsp;11. GCD curves for LaNiO\u003csub\u003e3\u003c/sub\u003e at 3M KOH solution at 1 A/g current density by (a) numerical modeling and (b) experiment.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\"\u003e\n \u003ch2\u003e4.1. Device modeling and comparing GCD Curves\u003c/h2\u003e\n \u003cp\u003eThe numerical modeling was performed using the MATLAB platform. The Nernst equation was used to determine equilibrium potentials, while the Butler-Volmer equation described current-potential relationships. Diffusion processes were modeled using Fick's laws [\u003cspan\u003e61\u003c/span\u003e]. This numerical modeling of the charge-discharge cycle for the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode is performed at 3 M KOH electrolyte at 1 A/g [\u003cspan\u003e62\u003c/span\u003e]. In Fig.\u0026nbsp;11 (a), the GCD curve shows a discharging time of about 20 s in 3 M KOH solution, which does not change for 3 consecutive segments but in Fig.\u0026nbsp;11 (b) we observed a discharging time near about 15.02 s, so here is a small discrepancy observed. This can be explained by recalling some attributes in our experimental measurements.\u003c/p\u003e\u003cbr\u003e\n \u003cp\u003e\u003cspan\u003e\u003cstrong\u003ei. Experimental Variability\u003c/strong\u003e:\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\n \u003cp\u003eExperiments inherently carry a degree of variability due to uncontrollable factors such as environmental conditions, impurities in materials, or variations in electrode preparation. Addressing and quantifying these sources of variability in the experimental setup can contribute to a more accurate comparison with the numerical model.\u003c/p\u003e\n \u003cp\u003e\u003cspan\u003e\u003cstrong\u003eii. Temperature Influence\u003c/strong\u003e:\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\n \u003cdiv\u003e\n \u003cp\u003eTemperature serves as a critical parameter in electrochemical systems, exerting a profound impact on reaction rates, ion mobility, and overall electrochemical kinetics. Disparities in the thermal conditions between the numerical model and the experimental setup can lead to variations in the observed discharging time.\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003eAlso how the pseudocapacitance will come up as a result of redox reaction between KOH electrolyte and LaNiO\u003csub\u003e3\u003c/sub\u003e is also to be studied.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec17\"\u003e\n \u003ch2\u003e4.2. DFT and Psudocapacitance\u003c/h2\u003e\n \u003cp\u003eThe Density of States calculation is performed for LaNiO\u003csub\u003e3\u003c/sub\u003e employing the Generalized Gradient Approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) functional, a widely used method for precisely describing electronic structures and properties of various materials. The LaNiO\u003csub\u003e3\u003c/sub\u003e crystal with space group \u003cem\u003eR\u003c/em\u003e ͞ 3\u003cem\u003ec\u003c/em\u003e is used in the model, with 30 sites in its unit cell. The cell volume of 337.57 Å\u003csup\u003e3\u003c/sup\u003e and the density is 7.24 g/cm\u003csup\u003e3\u003c/sup\u003e. Lanthanum ions (La³⁺) are arranged in a 9-coordinate geometry, forming bonds with nine identical oxygen ions (O²⁻). Among these bonds, three are shorter, measuring 2.43 Å, while the remaining six are longer, extending to 2.71 Å in length. Nickel ions (Ni³⁺) are connected to six identical oxygen ions (O²⁻), creating corner-sharing NiO₆ octahedra. These octahedra exhibit corner-sharing angles of 17°. All the nickel-oxygen (Ni–O) bond lengths in this arrangement measure 1.94 Å. Oxygen ions (O²⁻) adopt a 5-coordinate geometry, forming bonds with three identical lanthanum ions (La³⁺) and two identical nickel ions (Ni³⁺) in this structural configuration as shown in Fig.\u0026nbsp;\u003cspan\u003e12\u003c/span\u003e [63].\u003c/p\u003e\n \u003cp\u003eThe geometry optimization is performed followed by the energy calculations. The band energy tolerance of ~ 10\u003csup\u003e− 5\u003c/sup\u003e eV is used for convergence. The Quantum ESPRESSO software package is used to perform the calculations. The valence states treated are La 5s\u003csup\u003e2\u003c/sup\u003e 5p\u003csup\u003e6\u003c/sup\u003e 5d\u003csup\u003e1\u003c/sup\u003e electrons, Ni 3d\u003csup\u003e8\u003c/sup\u003e 4s\u003csup\u003e2\u003c/sup\u003e electrons, and O 2s\u003csup\u003e2\u003c/sup\u003e 2p\u003csup\u003e4\u003c/sup\u003e. The total Density of States (DOS) is shown in Fig.\u0026nbsp;\u003cspan\u003e13\u003c/span\u003e. The DOS of the total crystal structure is represented in Fig.\u0026nbsp;\u003cspan\u003e13\u003c/span\u003e, which gives a detailed insight into the electronic structure of the rhombohedral LaNiO\u003csub\u003e3\u003c/sub\u003e and the contributions of p and d orbitals across the energies. Figure\u0026nbsp;\u003cspan\u003e14\u003c/span\u003e shows the partial DOS for each of the atoms and the corresponding orbitals for each atom. The bands in the range − 8 eV to 0 eV mainly contributed by O 2p and Ni 3d orbitals. La 5d mainly contributes to the upper band around 6 eV hybridized orbital, indicating a weak La–O bond covalency. From the analysis of PDOS, the La atoms do not significantly contribute to the metallic nature of LaNiO\u003csub\u003e3\u003c/sub\u003e [\u003cspan\u003e47\u003c/span\u003e], [\u003cspan\u003e64\u003c/span\u003e].\u003c/p\u003e\n \u003cp\u003eDensity of States (DOS) calculations for LaNiO\u003csub\u003e3\u003c/sub\u003e give valuable insights into the electronic structure of this material, which can be related to its pseudocapacitance behavior when used as an electrode material with a 3M KOH electrolyte.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eEnergy Calculations and Convergence\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eGeometry optimization and energy calculations were performed with a high band energy tolerance of ~ 10\u003csup\u003e− 5\u003c/sup\u003e eV, ensuring accurate results. This level of precision is crucial for understanding the electronic properties relevant to pseudocapacitance.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eLa–O Bond Covalency\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe upper band around 6 eV, mainly contributed by La 5d hybridized orbitals, indicates a weak covalency in the La–O bond. This insight is valuable because it hints at the nature of chemical interactions between La and O, which can influence pseudocapacitance behavior.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eRole of La Atoms\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eFrom the partial DOS (PDOS) analysis, it is observed that La atoms do not significantly contribute to the metallic nature of LaNiO\u003csub\u003e3\u003c/sub\u003e. This is important because it suggests that the pseudocapacitance behavior primarily arises from the electronic states associated with Ni and O.\u003c/p\u003e\n \u003cp\u003eLaNiO\u003csub\u003e3\u003c/sub\u003e is known for its mixed-valence state, where nickel ions (Ni\u003csup\u003e3+\u003c/sup\u003e and Ni\u003csup\u003e4+\u003c/sup\u003e) can undergo reversible redox reactions. The KOH electrolyte dissociates into potassium (K\u003csup\u003e+\u003c/sup\u003e), hydroxide (OH\u003csup\u003e−\u003c/sup\u003e) ions, and water (H\u003csub\u003e2\u003c/sub\u003eO). The OH\u003csup\u003e−\u003c/sup\u003e ions play a crucial role in pseudocapacitive reactions. Pseudocapacitance arises from faradaic (redox) reactions that occur at the electrode-electrolyte interface. In the case of LaNiO\u003csub\u003e3\u003c/sub\u003e and KOH, here's how the pseudocapacitance reaction takes place:\u003c/p\u003e\n \u003cp\u003e\u003cspan\u003ea. \u003cstrong\u003eOxidation of Ni\u003c/strong\u003e: During the charging process (oxidation), Ni\u003csup\u003e3+\u003c/sup\u003e ions in LaNiO\u003csub\u003e3\u003c/sub\u003e lose electrons and transform into Ni\u003csup\u003e4+\u003c/sup\u003e ions. This is a redox reaction that stores charge.\u003cbr\u003e\u003c/span\u003e \u003cspan\u003eb. \u003cstrong\u003eHydroxide Ion Adsorption\u003c/strong\u003e: Simultaneously, OH\u003csup\u003e−\u003c/sup\u003e ions from the KOH electrolyte adsorb onto the surface of LaNiO\u003csub\u003e3\u003c/sub\u003e, forming Ni-OH surface groups. This adsorption process is highly reversible.\u003cbr\u003e\u003c/span\u003e \u003cspan\u003ec. \u003cstrong\u003eReduction of Ni\u003c/strong\u003e: During the discharging process (reduction), Ni\u003csup\u003e4+\u003c/sup\u003e ions gain electrons and revert to Ni\u003csup\u003e3+\u003c/sup\u003e ions, releasing the stored charge. This reduction process is associated with the release of hydroxide ions.\u003cbr\u003e\u003c/span\u003e \u003cspan\u003ed. \u003cstrong\u003eOverall Reaction\u003c/strong\u003e: The overall pseudocapacitance reaction can be summarized as:\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\n \u003cp\u003eCharging: Ni\u003csup\u003e3+\u003c/sup\u003e + OH\u003csup\u003e−\u003c/sup\u003e → Ni\u003csup\u003e4+\u003c/sup\u003e + e\u003csup\u003e−\u003c/sup\u003e + OH\u003csup\u003e−\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eDischarging: Ni\u003csup\u003e4+\u003c/sup\u003e + e\u003csup\u003e−\u003c/sup\u003e + OH\u003csup\u003e−\u003c/sup\u003e → Ni\u003csup\u003e3+\u003c/sup\u003e + OH\u003csup\u003e−\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eThe DFT calculations reveal detailed information about the electronic structure, particularly the contributions of the p and d orbitals to the overall DOS. Specifically, the Ni 3d and O 2p orbitals play a significant role in the charge storage mechanism. The density of states (DOS) and partial density of states (PDOS) for the La, Ni, and O atoms in the LaNiO\u003csub\u003e3\u003c/sub\u003e crystal structure, help to understand the pseudocapacitance behavior of LaNiO\u003csub\u003e3\u003c/sub\u003e when used as an electrode material. The PDOS analysis shows significant contributions from Ni 3d and O 2p orbitals around the Fermi level, indicating that these orbitals are actively involved in the electronic conduction and redox reactions, essential for pseudocapacitance. The nature of the La–O bond can be inferred from the PDOS. The lack of significant hybridization between La 5d and O 2p states near the Fermi level indicates a weak La–O covalency bond. This means that the La–O interaction is not contributing to the delocalized electronic states necessary for metallic conduction or redox activity. The weak covalency of the La–O bond implies that La atoms act more as structural stabilizers rather than active participants in charge storage.\u003c/p\u003e\n \n \n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this investigation, the LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite were successfully fabricated. Both energy storage techniques, like pseudocapacitor and EDLC are involved in LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrodes. It has outstanding electrochemical performance with long cycle life such as C\u003csub\u003es\u003c/sub\u003e of 218.57 F/g at 5 mV/s scan rate, E\u003csub\u003es\u003c/sub\u003e of 30.35 W h/kg, P\u003csub\u003es\u003c/sub\u003e of 1.58 kW/kg along with 94.57% retention after 3000 cycles, whereas LaNiO\u003csub\u003e3\u003c/sub\u003e perovskite electrode exhibits a C\u003csub\u003es\u003c/sub\u003e of 177.53 F/g at 5 mV/s scan rate, E\u003csub\u003es\u003c/sub\u003e of 24.65 W h/kg, P\u003csub\u003es\u003c/sub\u003e of 1.48 kW/kg and average cyclic stability with 73.35% retention after 3000 cycles, caused the presence of high porous and conductive AC on LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite increased the ions contact area coming from electrolyte as well as enhanced the electrical conductivity of the electrode, as a result, improved the overall electrochemical performance. The EIS result even demonstrates that the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode exhibits superior power performance due to its reduced internal resistance (R\u003csub\u003es\u003c/sub\u003e and R\u003csub\u003ect\u003c/sub\u003e) in comparison to the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode. Moreover, the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite material has significant advantages due to the low cost and availability of AC, lowering the total cost of the supercapacitor. Dunn's, b-fitting, and Randel Savic models show the storage contribution in the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode yielded better findings than the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode. DFT analysis indicates the structure of LaNiO\u003csub\u003e3\u003c/sub\u003e material is appropriate for significant energy storage and stability. So, considering all aspects, it can be said that the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode is a promising candidate for next-generation supercapacitor electrode applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eBC- Conceptualization, Methodology, Investigation, Writing - Original Draft, Visualization, Funding acquisition.AS- Formal analysis, Validation, Resources, Data Curation.BK : Software, Investigation, Writing - Review \u0026amp; Editing, Supervision, Project AdministrationAP: Investigation, Writing - Review \u0026amp; EditingDD: Investigation, Writing - Review \u0026amp; Editing,SP: Funding acquisition, Supervision, Writing - Review \u0026amp; Editing.All authors reviewed the manuscript.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAcknowledgement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge Suvamay Pramanik, Presidency University, 86/1 College Street, Kolkata-700073 for assistance with the electrochemical measurements.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZepeng Bai, Hongji Li, Mingji Li, Cuiping Li, Xufei Wang, Changqing Qu, Baohe Yang, \u0026ldquo;Flexible carbon nanotubes-MnO2/reduced graphene oxide-polyvinylidene fluoride films for supercapacitor electrodes,\u0026rdquo; \u003cem\u003eInt J Hydrogen Energy\u003c/em\u003e, vol. 40, no. 46, pp. 16306\u0026ndash;16315, Dec. 2015, doi: 10.1016/j.ijhydene.2015.09.065.\u003c/li\u003e\n\u003cli\u003eZ. 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Millis, \u0026ldquo;Quantifying electronic correlation strength in a complex oxide: A combined DMFT and ARPES study of LaNiO3,\u0026rdquo; \u003cem\u003ePhys Rev B Condens Matter Mater Phys\u003c/em\u003e, vol. 92, no. 24, Dec. 2015, doi: 10.1103/PhysRevB.92.245109.\u003c/li\u003e\n\u003cli\u003eX. Liao, V. Singh, and H. Park, \u0026ldquo;Oxygen vacancy induced site-selective Mott transition in LaNiO3,\u0026rdquo; \u003cem\u003ePhys Rev B\u003c/em\u003e, vol. 103, no. 8, Feb. 2021, doi: 10.1103/PhysRevB.103.085110.\u003c/li\u003e\n\u003cli\u003e\u0026Scaron;. Masys, S. Mickevičius, S. Grebinskij, and V. Jonauskas, \u0026ldquo;Electronic structure of LaNiO3-x thin films studied by x-ray photoelectron spectroscopy and density functional theory,\u0026rdquo; \u003cem\u003ePhys Rev B Condens Matter Mater Phys\u003c/em\u003e, vol. 82, no. 16, Oct. 2010, doi: 10.1103/PhysRevB.82.165120.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Perovskite, Nanocomposite, Supercapacitor, Energy storage, Energy contribution, DFT","lastPublishedDoi":"10.21203/rs.3.rs-4550514/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4550514/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePerovskite LaNiO\u003csub\u003e3\u003c/sub\u003e was synthesized with the help of the sol-gel method and LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite was produced via ultrasonication followed by filtration process keeping LaNiO\u003csub\u003e3\u003c/sub\u003e and activated carbon (AC) in an NMP solvent. The prepared electrode material was then coated on Ni foam with a mass loading of 28 mg/cm\u003csup\u003e2\u003c/sup\u003e. Various well-known characterization techniques such as TGA, FTIR, XRD, FESEM, and XPS were used to characterize the crystal structure and surface morphology of the sample. The electrochemical performance of the prepared electrodes was measured with cyclic voltammetry (CV), galvanometric charge-discharge (GCD), and electrochemical spectroscopy (EIS) using 3 M KOH as an electrolyte solution in two electrode configurations. The pure LaNiO\u003csub\u003e3\u003c/sub\u003e electrode exhibits a specific capacitance (C\u003csub\u003es\u003c/sub\u003e) of 177.53 F/g at 5 mV/s, cyclic stability with 73.35% capacitance retention after 3000 cycles, energy density of 24.65 W h/kg, and a power density of 1.48 kW/kg. whereas, The LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode delivered a high C\u003csub\u003es\u003c/sub\u003e of 218.57 F/g at a 5 mV/s scan rate with excellent cyclic stability of about 94.57% specific capacitance retention after 3000 cycles, the outstanding energy density of 30.35 W h/kg with a high-power density of 1.58 kW/kg. Additional investigation on the storage contribution using Dunn's, b-fitting, and Randel Savic models produced superior results with the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC nanocomposite electrode than with the LaNiO\u003csub\u003e3\u003c/sub\u003e electrode. DFT analysis further demonstrated LaNiO\u003csub\u003e3\u003c/sub\u003e material's strong electrochemical characteristics and stability. Thus, the LaNiO\u003csub\u003e3\u003c/sub\u003e@AC composite material can be the newest member of the supercapacitor electrode material with superior electrochemical performance.\u003c/p\u003e","manuscriptTitle":"Activated carbon-supported lanthanum nickel oxide (LaNiO3 ) perovskite nanocomposite supercapacitor electrode material exhibiting superior power-density and life cycle","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-08 17:10:18","doi":"10.21203/rs.3.rs-4550514/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-30T18:57:52+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-26T10:06:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-25T05:33:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-25T03:07:19+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-24T10:27:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-23T03:58:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-20T13:41:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"92293285345888508745405362057543298347","date":"2024-06-20T08:20:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"277036125107924315611679466357498977633","date":"2024-06-17T02:55:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"231033705037592814811690232489063465637","date":"2024-06-15T08:43:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"82520261546158804590753015232318263753","date":"2024-06-15T06:08:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155315610292456664134900176868902587236","date":"2024-06-15T01:56:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"137562938259000005628354328502739421686","date":"2024-06-15T01:43:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"182355594310904536396958280333743505330","date":"2024-06-15T01:11:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"204860021886013407400228087207905708785","date":"2024-06-14T23:28:17+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-14T20:31:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-13T01:37:21+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-13T01:37:12+00:00","index":"","fulltext":""},{"type":"submitted","content":"Ionics","date":"2024-06-08T12:05:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"915ae9bb-2602-423b-8192-6604b0b0c198","owner":[],"postedDate":"July 8th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2024-09-12T19:40:15+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-08 17:10:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4550514","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4550514","identity":"rs-4550514","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}