Synthesis and characterization of V2O5/rGO hybrid nanowire composites as electrode materials for energy storage applications

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A. Niaz, Abdul Shakoor Khan, Fayyaz Hussain, Aqsa Arooj, Sarfraz Ahmad, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6821782/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Aug, 2025 Read the published version in Journal of Inorganic and Organometallic Polymers and Materials → Version 1 posted 31 You are reading this latest preprint version Abstract Vanadium pentoxide V 2 O 5 a more recent candidate has gained much attention as an electrode material in the field of electrochemical energy storage devices. This work presents V 2 O 5 nanowires (NWs), synthesized by using a simple and efficient hydrothermal method. The nanowires composite rGO doped V 2 O 5 (V 2 O 5 /rGO) was also prepared by hydrothermal method. The DFT-based structural parameters of V₂O₅ and the V₂O₅/rGO composite indicate negative ground state energies, confirming the thermodynamic stability of both systems. Furthermore, the energy–volume (E–V) curve analysis reveals that the V₂O₅/rGO composite attains a lower minimum energy compared to pristine V₂O₅, suggesting enhanced structural stability upon the incorporation of rGO. The structural analysis and morphology of both V 2 O 5 NWs and V 2 O 5 /rGO were investigated and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the electrochemical properties were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and GCD (Galvanostatic Charge-Discharge) techniques. The quasi-rectangular shape-like curves with redox peaks were obtained by the cyclic voltammetry (CV), exhibiting that both the samples V 2 O 5 (NWs) and V 2 O 5 /rGO have pseudo-capacitive nature. Electrochemical Impedance Spectroscopy (EIS) revealed that there is an enhanced conductivity of V 2 O 5 /rGO than pure V 2 O 5 due to the low resistivity of V 2 O 5 /rGO nanocomposites. The specific capacitance of V 2 O 5 NWs was found to be 110.3 F/g at 10mv/s scan rate whereas for compositeV 2 O 5 /rGO the enhanced specific capacitance was 216.5 F/g at 10 mV/s scan rate. Similarly, results obtained from GCD (galvanostatic charge-discharge) indicate that charge/discharge time, as well as the specific capacitance of composite (V 2 O 5 /rGO), is much more enhanced than pure V 2 O 5 NWs electrode. The enhanced characteristics of V 2 O 5 /rGO are because of rGO nanosheets as they provide short diffusion distance for ions of electrolyte, high surface area, and large transfer of electrons. Structural analysis Electrochemical Nanowires Energy storage devices Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Due to the enormous consumption of fossil fuels and fear of environmental pollution, clean and renewable energy sources are becoming more important. However, the arrangement of these renewable energy technologies requires more efficient and reliable electrochemical energy systems (EES) that can store energy generated by sources and provide these energies when needed [ 1 ]. Moreover, rapid progress in the field of portable electronic devices as well as in electric vehicles, has increased interest in electrochemical energy storage devices. Therefore, recently explored highly efficient EES have got attention in industrial and research applications [ 2 ]. So, there is a need to explore new renewable and clean sources of energy so that economic growth may be maintained. The clean sources of energy are solar, geothermal, biomass, and wind. These energies can be converted to electrochemical energies for storage and resupply upon demand [ 3 ]. The selection of suitable electrode material is challenging ecologically and economically. The materials used as electrode materials are mostly carbonaceous materials such as carbon nanotubes (CNTs), activated carbon, graphite, graphene, metal oxides, and composites of metals with other metals etc. [ 4 – 6 ] Among all metals oxides that are studied exclusively as material for electrode in electrochemical capacitors (ECCs) and LIBs, the ruthenium oxide (RuO) was focused for many years [ 7 , 8 ]. The high cost of this material shifted the attention to other metal oxides, particularly TMO (transition metal oxides). Significantly, among all the TMO (transition metal oxides) vanadium pentoxide is highly focused as an electrode due to its cost-effectiveness, high density, ease of use, and high output voltage. Another important property of it is its layered structure which is responsible for providing many intercalation sites [ 9 – 11 ]. In the earth's crust, vanadium is 4th most abundant element (transition metal) after Fe, Ti, and Mn [ 12 ]. The titaniferous magnetite ores, petroleum, and metallurgical slags are the main sources of vanadium. Due to the hardness and high tensile strength of vanadium, nearly 80% of it is used as a steel additive [ 13 ]. The recent research on nano-scale vanadium oxides is being focused on as they exhibit better physical and chemical properties. Due to their nano-size structure, they have better lithium insertion. Vanadium belongs to the family of transition metal elements; its ground state electronic configuration is 3d 3 4s 2 . Unlike all the other transition metals (Ti, Cr, Mn, etc.), vanadium has all the states of oxidation with + 5 to + 2; among all these states + 5 and + 4 most stable. Vanadium oxide with oxidation states from + 2 to + 5 is V 2 O 5 , V 2 O 3 , VO 2, and VO [ 14 ]. The nano-sized vanadium oxide fabricated by the hydrothermal process has a structure equivalent to that of V 2 O 5 . Vanadium pentoxide (V 2 O 5 ) is an orange-red and acidic oxide characterized by layered and crystal shear structure [ 15 ]. These layers are formed by edge/corner-sharing of a square pyramid surrendered by vanadium ions. The square pyramids face up and face down themselves in the layer. The strong bonds (V-O-V) were present between these vanadium compounds and have very weak attractive forces between the layers, such as van der Waals forces [ 16 , 17 ]. Figure 1 and Fig. 2 show the schematic of the V 2 O 5 structure [ 18 ]. Due to its abundance, affordability, and ease of production vanadium pentoxides (V 2 O 5 ) have attracted much attention as cathode when compared to LiCoO 2 -based anodes whose capacity is 274 mAh/g, V 2 O 5 has much more theoretical capacity which is about 437 mAh/g [ 19 , 20 ]. Among all transition metal oxides, V 2 O 5 has the highest specific capacitance. However, some limitations are also noticed in the use of V 2 O 5 as electrode materials. These limitations may include ionic diffusivity, low conductivity, and low strength. Additionally, volumetric expansion and polarization are also problematic which affect the battery voltage and cause capacity fading. [ 21 ] But these factors can be minimized by the use of nano-scale V 2 O 5 [ 22 ]. During handling of V 2 O 5 nanoparticles, pulverization and agglomeration occurs, so to overcome these inadequacies, it is suggested that nanoparticles should be coated with carbonaceous materials. Graphene with its unique characteristics among all carbonaceous materials becomes prominent. [ 23 ] The graphene/V 2 O 5 nanocomposites have much-enhanced properties as compared to individual specimens. [ 24 ] D. Govindarajan at al . reported specific capacitance of V 2 O 5 is 112F/g at 10m v/s of scan rate and that of rGO/ V 2 O 5 is 218.4 F/g at the same scan rate which is two times more than pure V 2 O 5 . [ 25 ] Moreover, good charge /discharge time was observed by GCD. In this work, an improved performance of composite V 2 O 5 /rGO over V 2 O 5 is observed which is due to rGO that provides a short diffusion path, high surface area, and brief distance of transport. Structural Properties V 2 O 5 is known for having the highest oxygen states within the vanadium-oxygen compounds and is the most stable phase among vanadium oxides. The energy volume curves provide valuable insight into the structural stability of V 2 O 5, which crystallizes in the Pmn21 space group. The lattice parameters for this phase are a = 11.48 Å, b = 4.36 Å, and c = 3.555 Å. The primitive unit cell of V 2 O 5 contains four vanadium atoms and ten oxygen atoms, arranged in several layers in the xy plane, oriented perpendicular to the z axis. The computed structural parameters, like the distance of V-O and O-O in V 2 O 5, are displayed in Fig. 2 (a). Figure 2 (b) confirmed the structural stability of V 2 O 5 and V2O5/rGO by displaying their negative ground state energy. The volume at which the minimum energy for V 2 O 5 (− 9097 Ry) occurs is approximately 1334 a.u.³. This is quite close to the primitive cell volume of 1200.78 a.u. as reported by Ketelaar et al. [ 35 ]. Since these reported parameters closely match experimental findings, they have been adopted for use in the present study. The energy-volume curve shows that the V₂O₅/rGO composite reaches a lower minimum energy compared to pure V₂O₅, suggesting improved stability. This increased stability likely results from the interaction between V₂O₅ and the rGO support, which may help reduce structural relaxation, internal strain, or improve electronic interactions. As a result, the combined system settles into a more energetically favorable state. Materials Bond length (Å) Bond Angle (Å) Ground Volume V 0 (a.u 3 ) Ground Energy E 0 (Ry) V 2 O 5 V-O = 3.43 O-O = 2.98 V-V = 3.44 V-O-V = 150.8 O-V-O = 104.4 1334 -9097 V 2 O 5 /rGO - - 1337 -9110 2. Experimental 2.1. Preparation of Vanadium Pentoxide (V 2 O 5 ) nanowires The hydrothermal method was used to prepare ultra-long V 2 O 5 nanowires. Firstly, 30 mL of distilled water (H 2 O) was taken in a beaker, then 0.364 g of V 2 O 5 powder (Sigma Aldrich) was added to it. Solution was stirred for the uniform dispersion of powder. 5mL of hydrogen peroxide (H 2 O 2 ) was poured into the solution during stirring. When the color of the solution turned semi-transparent orange-red from yellow stirring was stopped. Then as prepared 40ml semitransparent orange-red solution was transferred to the 60 mL autoclave (Teflon-lined). Then, this autoclave was placed in an oven for about four days at 140°C. After this, the solution was washed with distilled water (H 2 O) to remove impurities. The final yellow product was dried at 50°C for 10 hours in a vacuum oven. The prepared dried powder was grinded in a mortar and pestle. 2.2. Preparation of Reduced Graphene Oxide (rGO) Hummer’s method was used to prepare reduced graphene oxide (rGO) [ 26 ]. 25 mL of concentrated sulfuric acid (H 2 SO 4 ) along with one gram of graphite (powder) was taken in a beaker, it was placed on a magnetic stirrer. The solution was stirred constantly. Then, 0.5g of sodium nitrate (NaNO 3 ) was added to the above solution and stirred briskly for about one hour. After that, 3g of potassium per magnate (KMnO 4 ) was gradually added into the solution during stirring. After 12 hours, a dense solution formed that was then diluted with 500 ml of distilled water. Afterwards, again 5ml of hydrogen peroxide (H 2 O 2 ) was poured during stir up. Finally, a dark brown solution was obtained. The obtained solution was washed with distilled water to remove impurities and dried in a vacuum oven. This dried powder of GO was reduced by heating at 350 ºC in an inert argon atmosphere for 12 hours. 2.3 Preparation of Composite rGO/V 2 O 5 Hydrothermal process was employed to synthesize composite rGO/V 2 O 5 . It started with 30 mL of distilled water (H 2 O) into a beaker,0.5 g of prepared vanadium pentoxide (V 2 O 5 ) and 1.49 grams of glucose in a beaker under constant magnetic stirring. The dispersed solution of rGO was weighed then added to the above-prepared mixture. The solution was stirred exuberantly for about 20 minutes. A few drops of ammonia solution (NH 4 OH, 37%) were also added to this mixture. Finally, the prepared mixture was put into a Teflon-lined autoclave, and this was sealed properly and placed into an oven for about 14 hours at about 130 ºC. The product was washed, dried, and grinded. 2.4. Preparation of Coin Cell The slurry of the electrode was prepared by mixing the active material, conductive carbon, and polyvinylidene fluoride (PVDF) binder in a weight ratio of 70:20:10 with 1-methyl-2-pyrrolidone (NMP) as solvent. Then the mixture was coated in copper foil and dried at 60°C for 12 h. The coin cell type batteries were constructed using the prepared material as an anode, lithium foil as a cathode, Whatman grade glass fiber as a separator, and 1.0 M LiPF 6 in EC/DMC = 50/50 (v/v) as electrolyte. The cells were tested at room temperature. The galvanostatic charge/discharge measurements were performed in the voltage range of 0.01–3.2 V at the Neware Battery testing system. 3. Result and Discussion The graphene oxide (GO) pattern of XRD that was prepared by the Hummer method is shown in Fig. 2 a. The X-ray diffraction pattern of reduced graphene oxide, synthesized V 2 O 5 (NWs) and the V 2 O 5 /rGO composite are shown in Fig. 2 b, 2 c and 2 d, respectively. The XRD peaks which were observed in V 2 O 5 (NWs) sample at 2θ values of 15.6°, 20.5°, 22°, 26.4°, 31.4°, 32.7°, 33.7°, 34.6°, 41.6°, 45.7°, 47.6°, 49.1°, 51.6°, 55.9°, and 59.2°. The orthorhombic type structure is confirmed by peaks matched with (JCPDS card 41-1426) and lattice parameters a = 11.51 A°, b = 3.56 A° and c = 4.37 A°, [ 32 ]. XRD of the V 2 O 5 NWs samples showed no presence of other diffraction peak. The intensity and sharpness of peaks exhibited good crystallinity. The average size of the crystal calculated by Scherrer‘s equation [ 33 ] was observed to be about 84 nm. The interplanar spacing of GO as calculated by Bragg s law is about 9.11 A° [ 34 ]. This confirms the many oxygen motifs are intercalated between graphite layers. At about 26° the dominant peak (110) shows the presence of reduced graphene oxide in the XRD pattern of composite V 2 O 5 /rGO as described in Fig. 2 d. The orthorhombic type of structure is confirmed by peaks from (JCPDS card 41-1426) with lattice parameters a = 11.51 A°, b = 3.56 A° and c = 4.37 A° [ 27 ]. The value of 2θ° ranged from 5 to 60°. XRD results confirmed that there is no impurity peak, explicating the purity of the composite. This confirms the many oxygen motifs are interlocked between graphite layers. At about 25° the peak exhibits the presence of reduced graphene oxide. The surface morphology of prepared V 2 O 5 NWs and V 2 O 5 /rGO composites were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) as shown in Fig. 3 . SEM image shown in Fig. 3 a V 2 O 5 nanowires quadrangle like morphology. The estimated diameter of prepared V 2 O 5 NWs was 80–100 nm with a few hundred micrometers of length. Similarly, Fig. 3 b shows the rGO-wrapped V 2 O 5 . It is observed that V 2 O 5 is dispersed homogeneously along layers of rGO. It is due to the hydrophilic nature of reduced graphene oxide (rGO), to minimize surface energy, the tiny particles coalesce. Figure 3 c shows the TEM image of pure V 2 O 5 NWs and Fig. 3 d shows the TEM image of composite V 2 O 5 /rGO image respectively. Moreover, the TEM image of composite V 2 O 5 /rGO shows successful wrapping of rGO on V 2 O 5 . In a cyclic voltammetry (CV) system, voltage is fixed at some specific range as a result developed current is measured. In this system electrolyte solution that contains material of interest is immersed in it with the arrangement of three electrode cells. In this technique, the potential/voltage is usually applied between the reference electrodes and working electrode whereas, the resulting produced current is measured across the working electrode and counter electrodes [ 28 ]. The CV curves of V 2 O 5 NWs are shown in Fig. 4 by using a potential window range from − 0.3 to 0.6V with increasing scan rate in the range from 10mv/s − 50mv/s. whereas, in Fig. 5 V 2 O 5 /rGO curves in voltage window from 0.1 to 0.6v at 10–50 mv/s range of scan rate is shown. The curves from Fig. 4 indicate that by increasing scan rates current response is increased, while the shapes of curves remain the same. So, this confirms that the rate of performance is good. The peak profile shows that a redox reaction is present during charge/discharge. The CV curves are symmetrical indicating a reversible faradic reaction as a mechanism of charge storage is a concern [ 29 ]. The CV curves of the V 2 O 5 /rGO composite (with rGO 5%) are shown in Fig. 5 , it indicates that these curves also contain sharp redox peaks that are nonlinear. The as-produced current of rGO/ V 2 O 5 composite is increased which indicates the capacitance of composite is high as compared to pure V 2 O 5 NWs. These curves show that the material exhibits pseudo-capacitive behavior as they are almost quasi-rectangular in shape. It is also observed that the area of CV curves gradually increases with increasing scan rates. It is due to an increase in current peaks in redox, which shows that charge storage at the surface of the electrode decreased as charge flow increased. When the scan rate is low, sufficient time is available for ions of electrolyte to reach on spongy (pores) of the material. These ions accumulate on the outer surface of the material at a high scan rate. So, it exhibits that, as the scan rate increases results in a decrease in specific capacitance. The specific capacitance is calculated by Eq. 1 [ 30 ]. $$\:{\text{C}}_{\text{s}\text{p}}\:=\:\frac{{\int\:}_{\text{a}}^{\text{b}}\text{I}\text{d}\text{V}}{2\left(\varDelta\:\text{V}\right)\text{m}\text{v}}$$ 1 In addition, also from Table 1 , we observed that 46% of capacitance is decreased in the case of V 2 O 5 NWs with scan rate up to 50mv/s, whereas in the case of composite V 2 O 5 /rGO, it is a 66% decrease in capacitance, which shows that the electrochemical stability of composite V 2 O 5 /rGO is good as compared with pure V 2 O 5 NWs. Table 1 Capacitance values of V 2 O 5 nanowire and V 2 O 5 /rGO composite at different scan rate Sr No. Scan Rate (mv/s) V 2 O 5 NWs (F/g) V 2 O 5 /rGO (5%rGO) (F/g) 1 10 110.3 216.5 2 20 86.4 185 3 30 65.1 162.3 4 40 58.2 152.9 5 50 51.5 143.2 The galvanostatic charge-discharge (GCD) is a reliable technique that is used to calculate the electrochemical capacitance (C p ) of a given substance under controlled conditions of current (at constant current). It is also used to show the sustainability of materials. The curves obtained from GCD of rGO, V 2 O 5, and V 2 O 5 /rGO at 1.5 A/g of current density in the presence of electrolyte use are shown in Fig. 6 . The obtained GCD curves are very similar to each other and typically show a symmetric triangular shape. Moreover, it is also observed that both results obtained from CV and GCD are in accordance. In addition, it is also observed that when the value of current density is small the more time the capacitor takes for charge-discharge operation, is because of enough release or insertion of electrolyte ions during the action of charge-discharge [ 31 ]. We can calculate the specific capacitance of material using GCD from the following Eq. 2 [ 32 ]. $$\:\text{C}\text{p}=\text{I}{\Delta\:}\text{t}/\text{m}{\Delta\:}\text{v}$$ 2 The estimated capacitance of GO, V 2 O 5, and V 2 O 5 /rGO is 337 Fg − 1 , 525 Fg − 1 , and 826 Fg − 1 measured by GCD at 1.5 Ag − 1 of current density. Table 2 Capacitance, energy density, and power density of rGO, V 2 O 5 NWs, and V 2 O 5 /rGO nanocomposites. Sample Capacitance (F/g) Energy density (Wh/Kg) Power density (W/Kg) GO 337 26.96 0.299 V 2 O 5 NWs 525 42 0.30 V 2 O 5 /rGO 826 66.08 0.2002 It is a common observation that when current density is higher than specific capacitance decreases due to voltage drop, and at higher current density there is a deficiency of active material that is associated with redox reaction [ 31 ]. From Table 2 it is observed that the capacitance of composite V 2 O 5 /rGO is 826 F/g which is much higher than pure V 2 O 5 NWs for which its value is 525 F/g. So, it is also observed that the overall performance of V 2 O 5 /rGO is enhanced as compared to base V 2 O 5 NWs. It has been observed that the presence of rGO in compositeV 2 O 5 /rGO improves the specific capacitance as the surface area increases diffusion path as well as migration path for ions of electrolyte is shortened and electrical conductivity increases due to contact between V 2 O 5 and rGO. By calculating power density (p) and energy density (E) we can further test the electrochemical performance of the material (electrode). So, Energy (E) and power (P) densities can be computed by following Eqs. 3 and 4 [ 32 ]. E= ½ CV 2 (3) \(\:\text{P}=\frac{\text{E}}{\text{t}}\) (4) So, the energy (E) and power (P) densities of V 2 O 5 NWs at 1.5A/ g current density are 42 Wh/Kg is 0.30 KW/Kg respectively. Similarly, the Energy (E) and Power (P) densities of V 2 O 5 /rGO at current density 1.5A/g are 66.08 Wh/kg and 0.2002 Kw/kg respectively. The Columbic efficiency of materials V 2 O 5 NWs and V 2 O 5 /rGO are calculated by Eq. 5 [ 33 ]. η = t d /t c ×100 (5) Where ‘η’ is Columbic efficiency, t d is the time of discharge, and t c is the time of charge. The 80% and 81% are calculated columbic efficiency of V 2 O 5 NWs and V 2 O 5 /rGO composite respectively. Impedance analysis was carried out at room temperature to study electrical behavior. It is a study of supercapacitor electrode performance that depends on frequency. EIS was carried out with frequencies ranging from (0.01Hz to 100 kHz). From this observation, we come to know the capacitive and resistive elements that are associated with the electrode. The first section of the plot of V 2 O 5 NWs shows a high-frequency region, while the second section which is a straight line shows low frequency. In addition, the starting region that is a semi-circle shows the faradaic (R ct ) charge transfer resistance and a vertical straight line indicates diffusive resistance (‘w’ Warburg impedance) [ 34 ]. For composite V 2 O 5 /rGO the Nyquist plot contains a semi-circle region that is a region of high frequency shows that its semi-circle has a smaller radius as compared to pure, which shows that charge transfer resistance (R ct ) is smaller and faradaic reaction kinetics is faster. In this case, rGO provides efficient pathways for the conduction of electrons and diffusion distance decreases for Li + intercalation and de-intercalation. Electrical conductivity enhanced. In addition, the portion of curves (inclined portion) at a low frequency on Nyquist plots is due to Warburg impedance ‘Z w '. The Warburg impedance ‘Z w ' is due to OH − ions transport/diffusion during redox reaction within pores of the electrode. The low-frequency vertical lines along the Z" (imaginary) axis exhibit that the material electrode confirms pseudo-capacitive characteristics. The electrochemical performance of both V 2 O 5 NWs and V 2 O 5 /rGO composite as an anode material for lithium-ion battery are also investigated. The charge-discharge performances at various current densities are shown in Fig. 8 a and 8 c. The specific capacities of V 2 O 5 NWs and V 2 O 5 /rGO was found as 610 and 830 mAh/g at 1000 mA/g, respectively. The usage of high-conductive graphene oxide has increased the capacity of vanadium oxide. The initial discharge capacity of the composites was significantly higher than that of the vanadium oxide cell, implying the incorporation of graphene aided in faster Li + ion diffusion by the enhanced electronic and ionic conductivity to the cell. In line with expectations, with increased discharge rates, the capacity deteriorates due to the high discharging current that cannot be sustained (rapid Li + intercalation). The long-term electrochemical cycling performance of the composites was evaluated at the current density of 1 A g − 1 . When the 500-cycle specific capacity-cycle number coulombic efficiency (%) profiles of the composite electrodes are examined (Fig. 3.8 b and d), it is seen that the battery performance of both materials continue as the number of cycles increases. The reason for the fluctuation seen in the cycle is due to the deviations caused by the temperature. After 500 cycles the coulombic efficiency was measured at almost 100% which indicates that the reversibility of the electrochemical reaction is very high. Conclusion This work presents that V 2 O 5 NWs and doped V 2 O 5 NWs with rGO were prepared using the hydrothermal method. Whereas rGO was prepared using the Hummers method. The results obtained from SEM and TEM revealed that rGO is successfully doped with V 2 O 5 NWs and the length of NWs was in the 80–100 nm range. The Electrochemical properties were investigated using CV, EIS, and GCD. The spectrum of impedance (EIS) exhibits that the resistivity of V 2 O 5 /rGO nanocomposite is much smaller than V 2 O 5 NWs which indicates that the conductivity of V 2 O 5 /rGO is more than pure V 2 O 5 NWs. In addition, the CV and GCD also show that there is an enhancement in specific capacitance of V 2 O 5 /rGO due to the presence of rGO. The observed specific capacitance of V 2 O 5 NWs and V 2 O 5 /rGO was 110.3 F/g and 216.5 F/g at a scan rate of 10 mv/s. The specific capacities of V 2 O 5 NWs and V 2 O 5 /rGO were calculated as 610 and 830 mAh/g at 1000 mA/g, respectively. This is due to the short diffusion length, high surface area, and large electron transfer provided by the presence of rGO. More significantly the low cost, abundance, and layered structure of V 2 O 5 /rGO composite may utilize it as the most suitable candidate for energy storage applications. Declarations Author Contribution Niaz Ahmad Niaz was responsible for data curation, methodology, investigation, formal analysis, visualization, and writing of the original draft. Abdul Shakoor contributed to methodology, investigation, and data curation. Fayyaz Hussain worked on methodology and formal analysis. Aqsa Arooj provided conceptualization, investigation, methodology, and editing of the writing. Sarfraz Ahmad supported resources and validation. Mudasra Kanwal was involved in conceptualization, investigation, methodology, supervision, and review and editing of the writing. Demet Ozer contributed to the investigation and resources. Munazza Tariq supported resources and data curation. N. R. Khalid provided supervision and review, and editing. Mohamed Ammar Tighezza contributed to the investigation and supervision. Acknowledgement The work was supported by Researcher Supporting Project number (RSPD2025R765), King Saud University, Riyadh, Saudia Arabia. References N.S. Choi, Z.H. Chen, S. A.Freunberger,X.L.Ji,Y.-K.Sun, K. Amine, G. Yushin, L.F. Nazar, J. Cho, Bruce, Challenges Facing Lithium Batteries and Electrical Double-Layer Capacitors. J. Angew Chem. Int. Ed. 51 , 9994–10024 (2012) X.Y. Lai, J.E. Halperta, D. Wang, Recent advances in micro-/nano-structured hollow spheres for energy applications: From simple to complex systems. J. Energy Environ. Sci. 5 , 5604–5618 (2012) V. Mathew, S. Kim, J. Kang, J. Gim, J. Song, J. 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Cite Share Download PDF Status: Published Journal Publication published 28 Aug, 2025 Read the published version in Journal of Inorganic and Organometallic Polymers and Materials → Version 1 posted Editorial decision: Revision requested 12 Jun, 2025 Reviews received at journal 12 Jun, 2025 Reviewers agreed at journal 12 Jun, 2025 Reviews received at journal 12 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviews received at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviews received at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers agreed at journal 10 Jun, 2025 Reviewers invited by journal 10 Jun, 2025 Editor assigned by journal 10 Jun, 2025 Submission checks completed at journal 09 Jun, 2025 First submitted to journal 04 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6821782","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":469966314,"identity":"b84dfb72-8805-4bba-a7a0-17e4d87950c9","order_by":0,"name":"N. A. Niaz","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIie3RuwrCMBSA4ZRAXQKuR7w8Q6SDij5MQyFdBRcHh4CQjq4FH6PgXAjEpeAasIsIzgV30TqIU5tRMP8QcoYvJAQhl+sXw/WSL0gXPqNvRfiol1qTd7kKqLElkw6+3pcFZ9k5uQFaz5noy7CRzLY+DVKzYIcy54CKmImBzhsJVYhGpOLsYEINnlRMQCxaSKdSpFIsS5kE72FFyHhLzOv5EPngiZrwtouRFU4LPoJS42mo40AOdNhMTsfsvtSvr9wnF1Nt5sNdX9JGUoc/u/p4H1rBN3lnQ1wul+uvegJN2kmdp1HiYQAAAABJRU5ErkJggg==","orcid":"","institution":"Bahauddin Zakariya University","correspondingAuthor":true,"prefix":"","firstName":"N.","middleName":"A.","lastName":"Niaz","suffix":""},{"id":469966315,"identity":"377b2ffb-ec6a-4a02-94e6-79ca03344627","order_by":1,"name":"Abdul Shakoor Khan","email":"","orcid":"","institution":"Bahauddin Zakariya University","correspondingAuthor":false,"prefix":"","firstName":"Abdul","middleName":"Shakoor","lastName":"Khan","suffix":""},{"id":469966316,"identity":"1c8b2075-d9ea-4b28-abd9-c033a464bf5d","order_by":2,"name":"Fayyaz Hussain","email":"","orcid":"","institution":"Bahauddin Zakariya University","correspondingAuthor":false,"prefix":"","firstName":"Fayyaz","middleName":"","lastName":"Hussain","suffix":""},{"id":469966317,"identity":"0c808169-085c-4bdf-8386-825e03caf844","order_by":3,"name":"Aqsa Arooj","email":"","orcid":"","institution":"DGIST, Daegu Gyeongbuk Institute of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Aqsa","middleName":"","lastName":"Arooj","suffix":""},{"id":469966318,"identity":"6e164ab9-d2f2-46e4-81b1-cbdff3ed81a9","order_by":4,"name":"Sarfraz Ahmad","email":"","orcid":"","institution":"The Islamia university of Bahwalpur","correspondingAuthor":false,"prefix":"","firstName":"Sarfraz","middleName":"","lastName":"Ahmad","suffix":""},{"id":469966319,"identity":"1156c568-19b8-42e9-bd0a-43f21b4e71ce","order_by":5,"name":"Mudasra Kanwal","email":"","orcid":"","institution":"Bahauddin Zakariya University","correspondingAuthor":false,"prefix":"","firstName":"Mudasra","middleName":"","lastName":"Kanwal","suffix":""},{"id":469966320,"identity":"8b4b8dbf-1f17-4cfa-bf58-14caf5ec18e8","order_by":6,"name":"Demet Ozer","email":"","orcid":"","institution":"University of Hacettepe","correspondingAuthor":false,"prefix":"","firstName":"Demet","middleName":"","lastName":"Ozer","suffix":""},{"id":469966321,"identity":"141b1999-d838-49b2-8b9f-f9ef8dac0ed6","order_by":7,"name":"Munazza Tariq","email":"","orcid":"","institution":"Bahauddin Zakariya University","correspondingAuthor":false,"prefix":"","firstName":"Munazza","middleName":"","lastName":"Tariq","suffix":""},{"id":469966324,"identity":"1b696a0c-1e1b-4711-9cd0-6fdc03fb14d0","order_by":8,"name":"N. R. Khalid","email":"","orcid":"","institution":"University of Okara","correspondingAuthor":false,"prefix":"","firstName":"N.","middleName":"R.","lastName":"Khalid","suffix":""},{"id":469966326,"identity":"3a06b2e1-aa0f-477c-8b8a-356ae1ef62b9","order_by":9,"name":"Mohamed Ammar Tighezza","email":"","orcid":"","institution":"King Saud University","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"Ammar","lastName":"Tighezza","suffix":""}],"badges":[],"createdAt":"2025-06-04 15:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6821782/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6821782/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10904-025-03994-z","type":"published","date":"2025-08-28T15:57:27+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84530608,"identity":"14a46deb-75b4-4b79-8923-320985603059","added_by":"auto","created_at":"2025-06-13 06:07:43","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":176963,"visible":true,"origin":"","legend":"\u003cp\u003ea) Schematic structure of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5 \u003c/sub\u003ealong the c axis [16-17], b) Vanadium pentoxide 3D structure [18]\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/7353fe31e66791b97f7f2fe4.png"},{"id":84530307,"identity":"eb02a2cc-3de3-4198-9d4c-d78d64022582","added_by":"auto","created_at":"2025-06-13 05:59:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":115372,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e Crystal structure of Orthorhombic V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e, \u003cstrong\u003e(b)\u003c/strong\u003e Energy Verses Volume graph of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e (red) and V2O5/rGO (blue) \u0026nbsp;\u0026nbsp;\u0026nbsp;\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/3d9f5a0c294da77d555bc6f2.png"},{"id":84530311,"identity":"5d63c6ba-5a7e-471d-9845-ee3fc4c73f1f","added_by":"auto","created_at":"2025-06-13 05:59:43","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":456497,"visible":true,"origin":"","legend":"\u003cp\u003eFig. 2. XRD pattern of a) graphene oxide, b) reduced graphene oxide, c) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowire and d) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite (where rGO is 5%)\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/a954f09601adb62bd20da4d5.png"},{"id":84530310,"identity":"aeb13289-df28-48fa-a4ca-865f726dfa26","added_by":"auto","created_at":"2025-06-13 05:59:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":312958,"visible":true,"origin":"","legend":"\u003cp\u003eFig.3. SEM micrograph of a) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e, b) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO, c) TEM images of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowires and d) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO nanocomposite\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/56717eede05a8c751a369fd8.png"},{"id":84530613,"identity":"75d4c781-01cb-4e97-8d87-d7c96bb85692","added_by":"auto","created_at":"2025-06-13 06:07:43","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":145967,"visible":true,"origin":"","legend":"\u003cp\u003eFig. 4. The CV patterns of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs at scan rates range (10 to 50 mV/s)\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/b7aeb15e33cb2cc81dbbba9e.png"},{"id":84532387,"identity":"184506cc-d2cf-44be-bc9f-0b8ddec824d0","added_by":"auto","created_at":"2025-06-13 06:23:43","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":160949,"visible":true,"origin":"","legend":"\u003cp\u003eFig.5. Cyclic voltammetry of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO (where GO is 5%)\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/ded0d956349f93259f815377.png"},{"id":84530317,"identity":"6a08f6fd-36a8-4f5d-b9c8-a3949c3f7420","added_by":"auto","created_at":"2025-06-13 05:59:43","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":68891,"visible":true,"origin":"","legend":"\u003cp\u003eFig. 6. Comparison of GCD curves of GO, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO (5%rGO)\u003c/p\u003e","description":"","filename":"image7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/0c2325991127e67ef7970565.jpeg"},{"id":84531619,"identity":"97c90f11-20fb-421e-abf9-0c8935470992","added_by":"auto","created_at":"2025-06-13 06:15:43","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":265654,"visible":true,"origin":"","legend":"\u003cp\u003eFig. 7. EIS spectrum of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/f5f27ce57ec9875e4420ffeb.png"},{"id":84530609,"identity":"83ab501e-7ed4-4a80-bf8d-39ed37169d03","added_by":"auto","created_at":"2025-06-13 06:07:43","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":158802,"visible":true,"origin":"","legend":"\u003cp\u003eFig. 8. Charge-discharge performances of a) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e and c) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e@rGO at various current densities, b) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e and d) V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e@rGO at 1000 mA/g current density\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/054b1fce2a4187e0c2e3dfd2.png"},{"id":90345013,"identity":"87219e00-6226-4884-b9c6-218b4da20682","added_by":"auto","created_at":"2025-09-01 16:09:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2600800,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6821782/v1/230109e7-aaca-44f9-a742-78be28fe8631.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSynthesis and characterization of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO hybrid nanowire composites as electrode materials for energy storage applications\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eDue to the enormous consumption of fossil fuels and fear of environmental pollution, clean and renewable energy sources are becoming more important. However, the arrangement of these renewable energy technologies requires more efficient and reliable electrochemical energy systems (EES) that can store energy generated by sources and provide these energies when needed [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Moreover, rapid progress in the field of portable electronic devices as well as in electric vehicles, has increased interest in electrochemical energy storage devices. Therefore, recently explored highly efficient EES have got attention in industrial and research applications [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. So, there is a need to explore new renewable and clean sources of energy so that economic growth may be maintained. The clean sources of energy are solar, geothermal, biomass, and wind. These energies can be converted to electrochemical energies for storage and resupply upon demand [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The selection of suitable electrode material is challenging ecologically and economically. The materials used as electrode materials are mostly carbonaceous materials such as carbon nanotubes (CNTs), activated carbon, graphite, graphene, metal oxides, and composites of metals with other metals etc. [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] Among all metals oxides that are studied exclusively as material for electrode in electrochemical capacitors (ECCs) and LIBs, the ruthenium oxide (RuO) was focused for many years [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The high cost of this material shifted the attention to other metal oxides, particularly TMO (transition metal oxides). Significantly, among all the TMO (transition metal oxides) vanadium pentoxide is highly focused as an electrode due to its cost-effectiveness, high density, ease of use, and high output voltage. Another important property of it is its layered structure which is responsible for providing many intercalation sites [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the earth's crust, vanadium is 4th most abundant element (transition metal) after Fe, Ti, and Mn [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The titaniferous magnetite ores, petroleum, and metallurgical slags are the main sources of vanadium. Due to the hardness and high tensile strength of vanadium, nearly 80% of it is used as a steel additive [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The recent research on nano-scale vanadium oxides is being focused on as they exhibit better physical and chemical properties. Due to their nano-size structure, they have better lithium insertion. Vanadium belongs to the family of transition metal elements; its ground state electronic configuration is 3d\u003csup\u003e3\u003c/sup\u003e4s\u003csup\u003e2\u003c/sup\u003e. Unlike all the other transition metals (Ti, Cr, Mn, etc.), vanadium has all the states of oxidation with +\u0026thinsp;5 to +\u0026thinsp;2; among all these states\u0026thinsp;+\u0026thinsp;5 and +\u0026thinsp;4 most stable. Vanadium oxide with oxidation states from +\u0026thinsp;2 to +\u0026thinsp;5 is V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, VO\u003csub\u003e2,\u003c/sub\u003e and VO [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe nano-sized vanadium oxide fabricated by the hydrothermal process has a structure equivalent to that of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e. Vanadium pentoxide (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e) is an orange-red and acidic oxide characterized by layered and crystal shear structure [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. These layers are formed by edge/corner-sharing of a square pyramid surrendered by vanadium ions. The square pyramids face up and face down themselves in the layer. The strong bonds (V-O-V) were present between these vanadium compounds and have very weak attractive forces between the layers, such as van der Waals forces [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003e show the schematic of the V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e structure [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDue to its abundance, affordability, and ease of production vanadium pentoxides (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e) have attracted much attention as cathode when compared to LiCoO\u003csub\u003e2\u003c/sub\u003e-based anodes whose capacity is 274 mAh/g, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e has much more theoretical capacity which is about 437 mAh/g [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong all transition metal oxides, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e has the highest specific capacitance. However, some limitations are also noticed in the use of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e as electrode materials. These limitations may include ionic diffusivity, low conductivity, and low strength. Additionally, volumetric expansion and polarization are also problematic which affect the battery voltage and cause capacity fading. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] But these factors can be minimized by the use of nano-scale V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. During handling of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanoparticles, pulverization and agglomeration occurs, so to overcome these inadequacies, it is suggested that nanoparticles should be coated with carbonaceous materials. Graphene with its unique characteristics among all carbonaceous materials becomes prominent. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] The graphene/V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanocomposites have much-enhanced properties as compared to individual specimens. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] D. Govindarajan \u003cem\u003eat al\u003c/em\u003e. reported specific capacitance of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e is 112F/g at 10m v/s of scan rate and that of rGO/ V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e is 218.4 F/g at the same scan rate which is two times more than pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] Moreover, good charge /discharge time was observed by GCD.\u003c/p\u003e \u003cp\u003eIn this work, an improved performance of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO over V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e is observed which is due to rGO that provides a short diffusion path, high surface area, and brief distance of transport.\u003c/p\u003e \u003cp\u003e \u003cb\u003eStructural Properties\u003c/b\u003e \u003c/p\u003e \u003cp\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e is known for having the highest oxygen states within the vanadium-oxygen compounds and is the most stable phase among vanadium oxides. The energy volume curves provide valuable insight into the structural stability of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5,\u003c/sub\u003e which crystallizes in the Pmn21 space group. The lattice parameters for this phase are a\u0026thinsp;=\u0026thinsp;11.48 \u0026Aring;, b\u0026thinsp;=\u0026thinsp;4.36 \u0026Aring;, and c\u0026thinsp;=\u0026thinsp;3.555 \u0026Aring;. The primitive unit cell of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e contains four vanadium atoms and ten oxygen atoms, arranged in several layers in the xy plane, oriented perpendicular to the z axis. The computed structural parameters, like the distance of V-O and O-O in V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5,\u003c/sub\u003e are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a). Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b) confirmed the structural stability of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e and V2O5/rGO by displaying their negative ground state energy.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe volume at which the minimum energy for V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e (\u0026minus;\u0026thinsp;9097 Ry) occurs is approximately 1334 a.u.\u0026sup3;. This is quite close to the primitive cell volume of 1200.78 a.u. as reported by Ketelaar et al. [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Since these reported parameters closely match experimental findings, they have been adopted for use in the present study.\u003c/p\u003e \u003cp\u003eThe energy-volume curve shows that the V₂O₅/rGO composite reaches a lower minimum energy compared to pure V₂O₅, suggesting improved stability. This increased stability likely results from the interaction between V₂O₅ and the rGO support, which may help reduce structural relaxation, internal strain, or improve electronic interactions. As a result, the combined system settles into a more energetically favorable state.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterials\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBond length (\u0026Aring;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBond Angle (\u0026Aring;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGround Volume V\u003csub\u003e0\u003c/sub\u003e(a.u\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGround Energy E\u003csub\u003e0\u003c/sub\u003e(Ry)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eV\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e\u003cb\u003eO\u003c/b\u003e\u003csub\u003e\u003cb\u003e5\u003c/b\u003e\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eV-O\u0026thinsp;=\u0026thinsp;3.43\u003c/p\u003e \u003cp\u003eO-O\u0026thinsp;=\u0026thinsp;2.98\u003c/p\u003e \u003cp\u003eV-V\u0026thinsp;=\u0026thinsp;3.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eV-O-V\u0026thinsp;=\u0026thinsp;150.8\u003c/p\u003e \u003cp\u003eO-V-O\u0026thinsp;=\u0026thinsp;104.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1334\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-9097\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eV\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e\u003cb\u003eO\u003c/b\u003e\u003csub\u003e\u003cb\u003e5\u003c/b\u003e\u003c/sub\u003e\u003cb\u003e/rGO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1337\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-9110\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Preparation of Vanadium Pentoxide (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e) nanowires\u003c/h2\u003e \u003cp\u003eThe hydrothermal method was used to prepare ultra-long V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowires. Firstly, 30 mL of distilled water (H\u003csub\u003e2\u003c/sub\u003eO) was taken in a beaker, then 0.364 g of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e powder (Sigma Aldrich) was added to it. Solution was stirred for the uniform dispersion of powder. 5mL of hydrogen peroxide (H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) was poured into the solution during stirring. When the color of the solution turned semi-transparent orange-red from yellow stirring was stopped. Then as prepared 40ml semitransparent orange-red solution was transferred to the 60 mL autoclave (Teflon-lined). Then, this autoclave was placed in an oven for about four days at 140\u0026deg;C. After this, the solution was washed with distilled water (H\u003csub\u003e2\u003c/sub\u003eO) to remove impurities. The final yellow product was dried at 50\u0026deg;C for 10 hours in a vacuum oven. The prepared dried powder was grinded in a mortar and pestle.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Preparation of Reduced Graphene Oxide (rGO)\u003c/h2\u003e \u003cp\u003eHummer\u0026rsquo;s method was used to prepare reduced graphene oxide (rGO) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. 25 mL of concentrated sulfuric acid (H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) along with one gram of graphite (powder) was taken in a beaker, it was placed on a magnetic stirrer. The solution was stirred constantly. Then, 0.5g of sodium nitrate (NaNO\u003csub\u003e3\u003c/sub\u003e) was added to the above solution and stirred briskly for about one hour. After that, 3g of potassium per magnate (KMnO\u003csub\u003e4\u003c/sub\u003e) was gradually added into the solution during stirring. After 12 hours, a dense solution formed that was then diluted with 500 ml of distilled water. Afterwards, again 5ml of hydrogen peroxide (H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) was poured during stir up. Finally, a dark brown solution was obtained. The obtained solution was washed with distilled water to remove impurities and dried in a vacuum oven. This dried powder of GO was reduced by heating at 350 \u0026ordm;C in an inert argon atmosphere for 12 hours.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Preparation of Composite rGO/V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e\u003c/h2\u003e \u003cp\u003eHydrothermal process was employed to synthesize composite rGO/V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e. It started with 30 mL of distilled water (H\u003csub\u003e2\u003c/sub\u003eO) into a beaker,0.5 g of prepared vanadium pentoxide (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e) and 1.49 grams of glucose in a beaker under constant magnetic stirring. The dispersed solution of rGO was weighed then added to the above-prepared mixture. The solution was stirred exuberantly for about 20 minutes. A few drops of ammonia solution (NH\u003csub\u003e4\u003c/sub\u003eOH, 37%) were also added to this mixture. Finally, the prepared mixture was put into a Teflon-lined autoclave, and this was sealed properly and placed into an oven for about 14 hours at about 130 \u0026ordm;C. The product was washed, dried, and grinded.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Preparation of Coin Cell\u003c/h2\u003e \u003cp\u003eThe slurry of the electrode was prepared by mixing the active material, conductive carbon, and polyvinylidene fluoride (PVDF) binder in a weight ratio of 70:20:10 with 1-methyl-2-pyrrolidone (NMP) as solvent. Then the mixture was coated in copper foil and dried at 60\u0026deg;C for 12 h. The coin cell type batteries were constructed using the prepared material as an anode, lithium foil as a cathode, Whatman grade glass fiber as a separator, and 1.0 M LiPF\u003csub\u003e6\u003c/sub\u003e in EC/DMC\u0026thinsp;=\u0026thinsp;50/50 (v/v) as electrolyte. The cells were tested at room temperature. The galvanostatic charge/discharge measurements were performed in the voltage range of 0.01\u0026ndash;3.2 V at the Neware Battery testing system.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Result and Discussion","content":"\u003cp\u003eThe graphene oxide (GO) pattern of XRD that was prepared by the Hummer method is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003ea. The X-ray diffraction pattern of reduced graphene oxide, synthesized V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e (NWs) and the V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003ec and \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, respectively.\u003c/p\u003e\u003cp\u003eThe XRD peaks which were observed in V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e (NWs) sample at 2θ values of 15.6\u0026deg;, 20.5\u0026deg;, 22\u0026deg;, 26.4\u0026deg;, 31.4\u0026deg;, 32.7\u0026deg;, 33.7\u0026deg;, 34.6\u0026deg;, 41.6\u0026deg;, 45.7\u0026deg;, 47.6\u0026deg;, 49.1\u0026deg;, 51.6\u0026deg;, 55.9\u0026deg;, and 59.2\u0026deg;. The orthorhombic type structure is confirmed by peaks matched with (JCPDS card 41-1426) and lattice parameters a\u0026thinsp;=\u0026thinsp;11.51 A\u0026deg;, b\u0026thinsp;=\u0026thinsp;3.56 A\u0026deg; and c\u0026thinsp;=\u0026thinsp;4.37 A\u0026deg;, [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. XRD of the V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs samples showed no presence of other diffraction peak. The intensity and sharpness of peaks exhibited good crystallinity. The average size of the crystal calculated by Scherrer\u0026lsquo;s equation [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] was observed to be about 84 nm. The interplanar spacing of GO as calculated by Bragg s law is about 9.11 A\u0026deg; [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. This confirms the many oxygen motifs are intercalated between graphite layers. At about 26\u0026deg; the dominant peak (110) shows the presence of reduced graphene oxide in the XRD pattern of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO as described in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003ed.\u003c/p\u003e \u003cp\u003eThe orthorhombic type of structure is confirmed by peaks from (JCPDS card 41-1426) with lattice parameters a\u0026thinsp;=\u0026thinsp;11.51 A\u0026deg;, b\u0026thinsp;=\u0026thinsp;3.56 A\u0026deg; and c\u0026thinsp;=\u0026thinsp;4.37 A\u0026deg; [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The value of 2θ\u0026deg; ranged from 5 to 60\u0026deg;. XRD results confirmed that there is no impurity peak, explicating the purity of the composite. This confirms the many oxygen motifs are interlocked between graphite layers. At about 25\u0026deg; the peak exhibits the presence of reduced graphene oxide.\u003c/p\u003e \u003cp\u003eThe surface morphology of prepared V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composites were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003e. SEM image shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003ea V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowires quadrangle like morphology. The estimated diameter of prepared V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs was 80\u0026ndash;100 nm with a few hundred micrometers of length. Similarly, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003eb shows the rGO-wrapped V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e. It is observed that V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e is dispersed homogeneously along layers of rGO. It is due to the hydrophilic nature of reduced graphene oxide (rGO), to minimize surface energy, the tiny particles coalesce.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003ec shows the TEM image of pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003ed shows the TEM image of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO image respectively. Moreover, the TEM image of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO shows successful wrapping of rGO on V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eIn a cyclic voltammetry (CV) system, voltage is fixed at some specific range as a result developed current is measured. In this system electrolyte solution that contains material of interest is immersed in it with the arrangement of three electrode cells. In this technique, the potential/voltage is usually applied between the reference electrodes and working electrode whereas, the resulting produced current is measured across the working electrode and counter electrodes [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The CV curves of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e by using a potential window range from \u0026minus;\u0026thinsp;0.3 to 0.6V with increasing scan rate in the range from 10mv/s \u0026minus;\u0026thinsp;50mv/s. whereas, in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003e V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO curves in voltage window from 0.1 to 0.6v at 10\u0026ndash;50 mv/s range of scan rate is shown.\u003c/p\u003e \u003cp\u003eThe curves from Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e indicate that by increasing scan rates current response is increased, while the shapes of curves remain the same. So, this confirms that the rate of performance is good. The peak profile shows that a redox reaction is present during charge/discharge. The CV curves are symmetrical indicating a reversible faradic reaction as a mechanism of charge storage is a concern [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe CV curves of the V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite (with rGO 5%) are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003e, it indicates that these curves also contain sharp redox peaks that are nonlinear. The as-produced current of rGO/ V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e composite is increased which indicates the capacitance of composite is high as compared to pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs.\u003c/p\u003e \u003cp\u003eThese curves show that the material exhibits pseudo-capacitive behavior as they are almost quasi-rectangular in shape. It is also observed that the area of CV curves gradually increases with increasing scan rates. It is due to an increase in current peaks in redox, which shows that charge storage at the surface of the electrode decreased as charge flow increased. When the scan rate is low, sufficient time is available for ions of electrolyte to reach on spongy (pores) of the material. These ions accumulate on the outer surface of the material at a high scan rate. So, it exhibits that, as the scan rate increases results in a decrease in specific capacitance. The specific capacitance is calculated by Eq.\u0026nbsp;\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{\\text{C}}_{\\text{s}\\text{p}}\\:=\\:\\frac{{\\int\\:}_{\\text{a}}^{\\text{b}}\\text{I}\\text{d}\\text{V}}{2\\left(\\varDelta\\:\\text{V}\\right)\\text{m}\\text{v}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eIn addition, also from Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, we observed that 46% of capacitance is decreased in the case of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003eNWs with scan rate up to 50mv/s, whereas in the case of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO, it is a 66% decrease in capacitance, which shows that the electrochemical stability of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO is good as compared with pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003eNWs.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCapacitance values of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowire and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite at different scan rate\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSr No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScan Rate\u003c/p\u003e \u003cp\u003e(mv/s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs\u003c/p\u003e \u003cp\u003e(F/g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO (5%rGO) (F/g)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e110.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e216.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e86.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e185\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e65.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e162.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e58.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e152.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e51.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e143.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe galvanostatic charge-discharge (GCD) is a reliable technique that is used to calculate the electrochemical capacitance (C\u003csub\u003ep\u003c/sub\u003e) of a given substance under controlled conditions of current (at constant current). It is also used to show the sustainability of materials. The curves obtained from GCD of rGO, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5,\u003c/sub\u003e and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO at 1.5 A/g of current density in the presence of electrolyte use are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe obtained GCD curves are very similar to each other and typically show a symmetric triangular shape. Moreover, it is also observed that both results obtained from CV and GCD are in accordance. In addition, it is also observed that when the value of current density is small the more time the capacitor takes for charge-discharge operation, is because of enough release or insertion of electrolyte ions during the action of charge-discharge [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWe can calculate the specific capacitance of material using GCD from the following Eq.\u0026nbsp;\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:\\text{C}\\text{p}=\\text{I}{\\Delta\\:}\\text{t}/\\text{m}{\\Delta\\:}\\text{v}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eThe estimated capacitance of GO, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5,\u003c/sub\u003e and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO is 337 Fg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 525 Fg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and 826 Fg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e measured by GCD at 1.5 Ag\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of current density.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCapacitance, energy density, and power density of rGO, V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs, and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO nanocomposites.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCapacitance\u003c/p\u003e \u003cp\u003e(F/g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eEnergy density\u003c/p\u003e \u003cp\u003e(Wh/Kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePower density\u003c/p\u003e \u003cp\u003e(W/Kg)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e337\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.299\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e525\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e826\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.2002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIt is a common observation that when current density is higher than specific capacitance decreases due to voltage drop, and at higher current density there is a deficiency of active material that is associated with redox reaction [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFrom Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e it is observed that the capacitance of composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO is 826 F/g which is much higher than pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs for which its value is 525 F/g. So, it is also observed that the overall performance of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO is enhanced as compared to base V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs. It has been observed that the presence of rGO in compositeV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO improves the specific capacitance as the surface area increases diffusion path as well as migration path for ions of electrolyte is shortened and electrical conductivity increases due to contact between V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e and rGO.\u003c/p\u003e \u003cp\u003eBy calculating power density (p) and energy density (E) we can further test the electrochemical performance of the material (electrode). So, Energy (E) and power (P) densities can be computed by following Eqs.\u0026nbsp;3 and 4 [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eE= \u0026frac12; CV\u003csup\u003e2\u003c/sup\u003e (3)\u003c/p\u003e\u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{P}=\\frac{\\text{E}}{\\text{t}}\\)\u003c/span\u003e\u003c/span\u003e (4)\u003c/p\u003e \u003cp\u003eSo, the energy (E) and power (P) densities of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs at 1.5A/ g current density are 42 Wh/Kg is 0.30 KW/Kg respectively. Similarly, the Energy (E) and Power (P) densities of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO at current density 1.5A/g are 66.08 Wh/kg and 0.2002 Kw/kg respectively. The Columbic efficiency of materials V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO are calculated by Eq.\u0026nbsp;5 [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eη\u0026thinsp;=\u0026thinsp;t\u003csub\u003ed\u003c/sub\u003e /t\u003csub\u003ec\u003c/sub\u003e \u0026times;100 (5)\u003c/p\u003e \u003cp\u003eWhere \u0026lsquo;η\u0026rsquo; is Columbic efficiency, t\u003csub\u003ed\u003c/sub\u003e is the time of discharge, and t\u003csub\u003ec\u003c/sub\u003e is the time of charge. The 80% and 81% are calculated columbic efficiency of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite respectively.\u003c/p\u003e \u003cp\u003eImpedance analysis was carried out at room temperature to study electrical behavior. It is a study of supercapacitor electrode performance that depends on frequency.\u003c/p\u003e \u003cp\u003eEIS was carried out with frequencies ranging from (0.01Hz to 100 kHz). From this observation, we come to know the capacitive and resistive elements that are associated with the electrode. The first section of the plot of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs shows a high-frequency region, while the second section which is a straight line shows low frequency. In addition, the starting region that is a semi-circle shows the faradaic (R\u003csub\u003ect\u003c/sub\u003e) charge transfer resistance and a vertical straight line indicates diffusive resistance (\u0026lsquo;w\u0026rsquo; Warburg impedance) [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. For composite V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO the Nyquist plot contains a semi-circle region that is a region of high frequency shows that its semi-circle has a smaller radius as compared to pure, which shows that charge transfer resistance (R\u003csub\u003ect\u003c/sub\u003e) is smaller and faradaic reaction kinetics is faster. In this case, rGO provides efficient pathways for the conduction of electrons and diffusion distance decreases for Li\u003csup\u003e+\u003c/sup\u003e intercalation and de-intercalation. Electrical conductivity enhanced.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition, the portion of curves (inclined portion) at a low frequency on Nyquist plots is due to Warburg impedance \u0026lsquo;Z\u003csub\u003ew\u003c/sub\u003e'. The Warburg impedance \u0026lsquo;Z\u003csub\u003ew\u003c/sub\u003e' is due to OH\u003csup\u003e\u0026minus;\u003c/sup\u003e ions transport/diffusion during redox reaction within pores of the electrode. The low-frequency vertical lines along the Z\" (imaginary) axis exhibit that the material electrode confirms pseudo-capacitive characteristics.\u003c/p\u003e \u003cp\u003eThe electrochemical performance of both V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite as an anode material for lithium-ion battery are also investigated. The charge-discharge performances at various current densities are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ea and \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ec. The specific capacities of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO was found as 610 and 830 mAh/g at 1000 mA/g, respectively. The usage of high-conductive graphene oxide has increased the capacity of vanadium oxide. The initial discharge capacity of the composites was significantly higher than that of the vanadium oxide cell, implying the incorporation of graphene aided in faster Li\u003csup\u003e+\u003c/sup\u003e ion diffusion by the enhanced electronic and ionic conductivity to the cell. In line with expectations, with increased discharge rates, the capacity deteriorates due to the high discharging current that cannot be sustained (rapid Li\u003csup\u003e+\u003c/sup\u003e intercalation). The long-term electrochemical cycling performance of the composites was evaluated at the current density of 1 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. When the 500-cycle specific capacity-cycle number coulombic efficiency (%) profiles of the composite electrodes are examined (Fig.\u0026nbsp;3.8 b and d), it is seen that the battery performance of both materials continue as the number of cycles increases. The reason for the fluctuation seen in the cycle is due to the deviations caused by the temperature. After 500 cycles the coulombic efficiency was measured at almost 100% which indicates that the reversibility of the electrochemical reaction is very high.\u003c/p\u003e "},{"header":"Conclusion","content":"\u003cp\u003eThis work presents that V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and doped V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs with rGO were prepared using the hydrothermal method. Whereas rGO was prepared using the Hummers method. The results obtained from SEM and TEM revealed that rGO is successfully doped with V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and the length of NWs was in the 80\u0026ndash;100 nm range. The Electrochemical properties were investigated using CV, EIS, and GCD. The spectrum of impedance (EIS) exhibits that the resistivity of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO nanocomposite is much smaller than V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs which indicates that the conductivity of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO is more than pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs. In addition, the CV and GCD also show that there is an enhancement in specific capacitance of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO due to the presence of rGO. The observed specific capacitance of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO was 110.3 F/g and 216.5 F/g at a scan rate of 10 mv/s. The specific capacities of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e /rGO were calculated as 610 and 830 mAh/g at 1000 mA/g, respectively. This is due to the short diffusion length, high surface area, and large electron transfer provided by the presence of rGO. More significantly the low cost, abundance, and layered structure of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO composite may utilize it as the most suitable candidate for energy storage applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eNiaz Ahmad Niaz was responsible for data curation, methodology, investigation, formal analysis, visualization, and writing of the original draft. Abdul Shakoor contributed to methodology, investigation, and data curation. Fayyaz Hussain worked on methodology and formal analysis. Aqsa Arooj provided conceptualization, investigation, methodology, and editing of the writing. Sarfraz Ahmad supported resources and validation. Mudasra Kanwal was involved in conceptualization, investigation, methodology, supervision, and review and editing of the writing. Demet Ozer contributed to the investigation and resources. Munazza Tariq supported resources and data curation. N. R. Khalid provided supervision and review, and editing. Mohamed Ammar Tighezza contributed to the investigation and supervision.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e \u003cp\u003eThe work was supported by Researcher Supporting Project number (RSPD2025R765), King Saud University, Riyadh, Saudia Arabia.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eN.S. Choi, Z.H. Chen, S. A.Freunberger,X.L.Ji,Y.-K.Sun, K. Amine, G. Yushin, L.F. Nazar, J. Cho, Bruce, Challenges Facing Lithium Batteries and Electrical Double-Layer Capacitors. J. Angew Chem. Int. Ed. \u003cb\u003e51\u003c/b\u003e, 9994\u0026ndash;10024 (2012)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eX.Y. Lai, J.E. Halperta, D. Wang, Recent advances in micro-/nano-structured hollow spheres for energy applications: From simple to complex systems. J. Energy Environ. 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Nature. \u003cb\u003e137\u003c/b\u003e(3460), 316\u0026ndash;316 (1936)\u003c/span\u003e\u003c/li\u003e\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":"journal-of-inorganic-and-organometallic-polymers-and-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"joip","sideBox":"Learn more about [Journal of Inorganic and Organometallic Polymers and Materials](https://www.springer.com/journal/10904)","snPcode":"10904","submissionUrl":"https://submission.nature.com/new-submission/10904/3","title":"Journal of Inorganic and Organometallic Polymers and Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Structural analysis, Electrochemical, Nanowires, Energy storage devices","lastPublishedDoi":"10.21203/rs.3.rs-6821782/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6821782/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eVanadium pentoxide V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e a more recent candidate has gained much attention as an electrode material in the field of electrochemical energy storage devices. This work presents V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e nanowires (NWs), synthesized by using a simple and efficient hydrothermal method. The nanowires composite rGO doped V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO) was also prepared by hydrothermal method. The DFT-based structural parameters of V₂O₅ and the V₂O₅/rGO composite indicate negative ground state energies, confirming the thermodynamic stability of both systems. Furthermore, the energy\u0026ndash;volume (E\u0026ndash;V) curve analysis reveals that the V₂O₅/rGO composite attains a lower minimum energy compared to pristine V₂O₅, suggesting enhanced structural stability upon the incorporation of rGO. The structural analysis and morphology of both V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO were investigated and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the electrochemical properties were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and GCD (Galvanostatic Charge-Discharge) techniques. The quasi-rectangular shape-like curves with redox peaks were obtained by the cyclic voltammetry (CV), exhibiting that both the samples V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e(NWs) and V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO have pseudo-capacitive nature. Electrochemical Impedance Spectroscopy (EIS) revealed that there is an enhanced conductivity of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO than pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e due to the low resistivity of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO nanocomposites. The specific capacitance of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs was found to be 110.3 F/g at 10mv/s scan rate whereas for compositeV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO the enhanced specific capacitance was 216.5 F/g at 10 mV/s scan rate. Similarly, results obtained from GCD (galvanostatic charge-discharge) indicate that charge/discharge time, as well as the specific capacitance of composite (V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO), is much more enhanced than pure V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e NWs electrode. The enhanced characteristics of V\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e/rGO are because of rGO nanosheets as they provide short diffusion distance for ions of electrolyte, high surface area, and large transfer of electrons.\u003c/p\u003e","manuscriptTitle":"Synthesis and characterization of V2O5/rGO hybrid nanowire composites as electrode materials for energy storage applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-13 05:59:38","doi":"10.21203/rs.3.rs-6821782/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision 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