Spatially Confined Ni3Se4/C Architecture via Continuous Selenization: Dual-Role Carbon Matrix Enables Ultrahigh-Rate Lithium Storage and Reveals Sodium-Ion Transport Limitations

Spatially Confined Ni3Se4/C Architecture via Continuous Selenization: Dual-Role Carbon Matrix Enables Ultrahigh-Rate Lithium Storage and Reveals Sodium-Ion Transport Limitations | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Spatially Confined Ni 3 Se 4 /C Architecture via Continuous Selenization: Dual-Role Carbon Matrix Enables Ultrahigh-Rate Lithium Storage and Reveals Sodium-Ion Transport Limitations Chenhao Zhao, Jianming Fan, Zhibiao Hu, Fengzhang Tu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7261910/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 15 You are reading this latest preprint version Abstract Nickel selenides' structural diversity offers promising avenues for advanced battery anodes, yet their practical implementation faces persistent challenges of structural instability and sluggish kinetics. Addressing these limitations, we pioneer a spatially confined architecture through template-directed hydrothermal synthesis: ~48 nm Ni 3 Se 4 nanoparticles uniformly encapsulated within conductive carbon nanoplates. Time-dependent XRD analysis confirms continuous selenization-driven phase evolution, while XPS/TGA verify the composite (30.6 wt% carbon) comprises Ni 2+ , Se 2 2- and Se 2- species. This dual-role design - where carbon simultaneously serves as electron highway and volume-change buffer - enables breakthrough lithium storage performance: 586.2 mAh g -1 after 100 cycles (0.2 A g -1 ) with exceptional 375.5 mAh g -1 retention at ultrahigh 5 A g -1 . Electrochemical analysis demonstrates carbon spacers reduce charge-transfer resistance by >40% versus bare counterparts. The strategically engineered interface provides critical insights for stabilizing conversion-type anodes, though sodium storage remains challenging (167.9 mAh g -1 after 100 cycles), highlighting fundamental differences in ion storage mechanisms that guide future material design. Ni3Se4/C hybrid Template-directed hydrothermal synthesis Progressive selenization Lithium/Sodium ion storage Carbon-encapsulated architecture Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Introduction Substantial efforts have focused on enhancing high-capacity anodes for lithium-ion (LIBs) and sodium-ion batteries (SIBs) over the past decade [1-3]. Transition metal oxides and sulfides represent extensively researched alternative anode systems, with significant investigations addressing their synthesis protocols, electrochemical performance, and underlying storage mechanisms [4-7]. Concurrently, selenium-based compounds have emerged as viable anode candidates following rigorous recent evaluation [8-14]. Despite exhibiting moderate theoretical capacities due to inherent mass constraints, these chalcogenides demonstrate compensatory advantages through enhanced charge transfer kinetics (attributed to narrow bandgaps) and substantial interfacial charge storage contributions [8,15–18]. For example, Ji et al. have made a comparative study of Co 3 O 4 , Co 3 S 4 , Co 3 Se 4 as SIBs anodes. It is found that Co 3 Se 4 with a close discharge capacity possesses much better cycling stability and rate capacity than two other samples [19]. Metal selenides face similar operational challenges to transition metal oxides and sulfides when deployed as battery anodes. Significant volume fluctuations during cycling frequently trigger structural degradation and rapid capacity fading. Concurrently, insufficient electroactive interfaces between electrode and electrolyte phases restrict reaction kinetics and rate performance [12-18,20]. Consequently, constructing metal selenide/carbon heterostructures represents a prevalent optimization strategy. Within this category, architectures featuring selenium-based nanoparticles encapsulated within carbon matrices have gained extensive adoption. Such core-shell configurations simultaneously enhance mass/charge transfer kinetics while accommodating volumetric stresses - collectively enabling superior cyclic endurance [12-14]. Besides the structure and morphologies design, there are also many types of metal selenides due to variable valence of selenium (-1 or -2). For example, the nickel selenides can be synthesized as NiSe, Ni 0.85 Se, Ni 3 Se 4 or NiSe 2 accompanying with the elevated selenization degree [21], and it has been proved that the NiSe, Ni 0.85 Se, NiSe 2 can be used as LIBs or SIBs anodes [13, 22-25]. As a transition composition between NiSe and NiSe 2 (Ni 0.5 Se), Ni 3 Se 4 (Ni 0.75 Se) has been regarded as a promising electrocatalyst or supercapacitor [26, 27]. Also, the sodium storage performances of Ni 3 Se 4 are studied combing with CoSe 2 [9]. To our best knowledge, the electrochemical performances of bare Ni 3 Se 4 as LIBs or SIBs anode materials have not been reported, and it should be available to be investigated according to the performances of NiSe and NiSe 2 . This work reports a hydrothermal synthesis of Ni 3 Se 4 and its carbon composite using distinct nickel precursors. Structural evolution, formation pathways, and electrochemical behavior as anode materials in both LIB and SIBs are systematically investigated. Experimental All precursor materials were A.R.grade and utilized without further purification. Ni 3 Se 4 and its carbon composite were synthesized through hydrothermal processing using the following protocol: Synthesis of Ni/C nanoplates : Ni/C nanoplates were synthesized via a modified sol-gel method adapted from reference [28], involving dissolution of 0.4 g NiCl 2 ·6H 2 O, 1.0 g citric acid, and 5.0 g urea in a binary solvent system (150 mL ethanol : 50 mL deionized water). This solution underwent constant stirring at 85 ℃ until transitioning into a green hydrogel, which was subsequently dehydrated at 80 ℃ for 12 hours before stepwise pyrolysis under argon atmosphere: 350 ℃ (2 h) followed by 700 ℃ (4 h). The resulting Ni/C composite was cooled to ambient temperature and mechanically pulverized. For comparative analysis, parallel syntheses employed stoichiometric equivalents of 0.2 g and 0.6 g NiCl 2 ·6H 2 O precursors, yielding designated 0.2-Ni/C and 0.6-Ni/C variants respectively, with the standard 0.4-Ni/C designation corresponding to the 0.4 g precursor formulation. Synthesis of Ni 3 Se 4 /C hybrid: 60 mg of Ni/C composite underwent ultrasonic dispersion in 10 mL deionized water. In a separate vessel, 157.9 mg selenium powder (200 mesh, Aladdin) was combined with 5 mL deionized water. Under magnetic agitation, 113.5 mg NaBH 4 was introduced to initiate reduction, yielding a homogeneous selenide solution. The selenide solution was transferred to the Ni/C dispersion, then sealed within a 25 mL Teflon-lined autoclave. The system was maintained at 160 ℃ for 12 hours. The resultant black precipitate was vacuum-filtered, sequentially washed with deionized water and ethanol (≥3 cycles), and vacuum-dried at 80 ℃ for 12 hours. Synthesis of Ni 3 Se 4 nanoparticle: The synthetic route is consistent with the synthesis of Ni 3 Se 4 /C except the Ni source is replaced to 0.2 g of NiCl 2 ·6H 2 O. Structural characterization : Crystallographic properties of synthesized materials were determined via X-ray diffraction (PANalytical X'Pert Powder 3 , Cu-Kα radiation at 40 kV/30 mA). Microstructural evaluation employed complementary scanning electron microscopy (Hitachi S-3400) and transmission electron microscopy (JEOL JEM-2100F) to assess morphological evolution across Ni/C, Ni 3 Se 4 , and Ni 3 Se 4 /C specimens. Specific surface areas and pore size distributions were derived from N₂ adsorption-desorption isotherms recorded at 77 K using a Micromeritics TriStar II 3020 analyzer. Chemical composition analysis employed X-ray photoelectron spectroscopy (Thermo Escalab 250Xi), while thermal decomposition profiles were acquired via thermogravimetric analysis (Netzsch DSC 200PC) at 5 ℃ min⁻¹ under air atmosphere. Electrochemical characterization : All electrochemical evaluations employed CR2016 coin cells configured with Li/Na counter electrodes and Ni 3 Se 4 -based working electrodes. The cathode slurry was formulated by homogenizing Ni 3 Se 4 /C composite, acetylene black, and sodium alginate binder (7:2:1 mass ratio) in an agate mortar. This mixture was subsequently aqueous-slurried and doctor-bladed onto copper current collectors. After vacuum baking at 80 ℃ for 5 hours, the coated foils underwent precision punching into 14 mm diameter discs. CR2016 coin cells were fabricated within an argon-saturated glovebox. Lithium foil disks (Ø14.5 mm) served as dual-function counter/reference electrodes in lithium-ion test cells. The electrochemical configuration employed Celgard 2400 polymeric separators paired with CapChem LBC-301 electrolyte (Shenzhen CapChem Technology Co.). For sodium ion module cells, the sodium plate with diameter of 15.0 mm self-made from sodium reagent (Sinophram) was used as both counter and reference electrodes. Polymer membrane (PFM, Foshan Jinhui) and 1 M NaCF 3 SO 4 DEGDME solution (Nanjing Mojiesi) were used as separator and electrolyte. Galvanostatic charge-discharge characterization for both lithium- and sodium-ion battery systems was executed on a Neware CT-3008 electrochemical platform (Shenzhen Neware Electronics Co.) using standardized testing parameters: constant current density of 0.2 A g -1 within a 0.01-2.8 V operational window. Complementary cyclic voltammetric analysis employed a CH Instruments 660C workstation, with all sweeps conducted across the identical 0.01-2.8 V potential range at multiple scan rates to evaluate reaction kinetics. Results and discussion The Ni 3 Se 4 /C composite was synthesized hydrothermally using Ni/C as precursor material. Figure 1 a displays the XRD pattern of 0.4-Ni/C, where diffraction peaks align with metallic nickel reference data (JCPDS: 87–0712). An asterisk-marked broad peak at 26° (2θ) indicates carbon presence originating from citric acid carbonization.After hydrothermal selenization, the nickel selenide can be obtained, and corresponding XRD pattern is revealed in Fig. 1 b. It is found that all of diffraction peaks can be attributed to monoclinic Ni 3 Se 4 (JCPDS: 89-7162). The sharp diffraction peaks indicate the Ni 3 Se 4 is well-crystallized. Furthermore, the wide peak sign indicating the coexistence of carbon can be retained in Fig. 1 b. As we know, the nickel selenides have several chemical compositions, such as NiSe, Ni 0.85 Se, Ni 3 Se 4 and NiSe 2 [ 21 ]. Among them, the pyrite-type NiSe 2 , a thermodynamically stable compound, can be readily obtained by gas diffusion or liquid-phase ion exchange reaction in presence of enough selenium [ 22 , 25 ], and the others generally are prepared by hydro/solvothermal assisted selenization method in presence of insufficient selenium or some special processes (e. g. low reaction temperature) [ 21 , 23 , 29 ]. In the present study, the monoclinic Ni 3 Se 4 are prepared by hydrothermal route. Considering the complexity of hydrothermal reaction, and it is necessary to specify the formation process of Ni 3 Se 4 . $$0.85\text{N}\text{i} +0.7\text{S}{\text{e}^{2-}}+\text{S}\text{e}_{2}^{{2-}}{\text{ = }}\text{N}{\text{i}_{0.85}}\text{S}\text{e}+1.7\text{S}{\text{e}^{2-}}$$ When the reaction time is increased to 1 h or more, some XRD characteristic peaks of Ni 3 Se 4 can be found, especially a (013) diffraction peak marked by dotted line appears, and the peaks splitting of (020)/(310) diffraction peaks surrounded by frame (Fig. 2 b) happens, indicating the gradually formation of Ni 3 Se 4 (or described as Ni 0.75 Se). A continuous selenization caused by Se 2 2− may be responsible for the formation of Ni 3 Se 4 . In order to furthermore study the formation process of Ni 3 Se 4 , the Ni source is replaced to 0.2 g NiCl 2 ·6H 2 O, and time-dependent XRD patterns of nickel selenides are shown in Fig. S1 . Initially, the Ni 2+ reacts with Se 2− to form NiSe, and then the NiSe is further selnizated with Se 2 2− to form Ni 0.85 Se and Ni 3 Se 4 accompanying with increased reaction time, which is similar with the formation of Ni 3 Se 4 from metallic Ni (Fig. 2 a). The formation condition of Ni 3 Se 4 is also studied using different Ni/C composites, 0.2-Ni/C (poor-Ni sample) and 0.6-Ni/C (rich-Ni sample), and the XRD patterns are revealed in Fig. 2 b. The Ni 0.85 Se can be obtained from 0.6-Ni/C, while a mixture of Ni 0.75 Se and NiSe 2 can be produced from 0.2-Ni/C. According to above results, a low or high Ni/Se ratio may be difficult to obtain Ni 3 Se 4 . Morphologies and surface structure of 0.4-Ni/C and Ni 3 Se 4 /C are observed by SEM, as shown in Fig. 3 . It is clear that the 0.4-Ni/C possesses morphology of nanoplate with a size of tens of microns (Fig. 3 a), and the nanoplate is made of carbon derived from citric acid. In a close view, some nanoparticles encapsulated into carbon nanoplate can be found (Fig. 3 b). After hydrothermal selenization, the SEM images of Ni 3 Se 4 /C are also shown in Fig. 3 c. The composite partially shows nanoplate-like structure, inheriting from 0.4-Ni/C, while the agglomeration turns to serious compared with precursor. In Fig. 4 d, some nanoparticles which encapsulated into carbon nanoplate can be clearly presented compared with Fig. 3 b. It is due to the transformation from metallic Ni to Ni 3 Se 4 , resulting into the particle growth. Transmission electron microscopy (Fig. 4 ) reveals the morphological evolution from 0.4-Ni/C precursor to Ni 3 Se 4 /C composite. Figure 4 a distinctly shows carbon-encapsulated nickel nanoparticles (∼48 nm) exhibiting faceted crystallographic features. Post-hydrothermal selenization preserves the nanoplate architecture (Fig. 4 b), while inducing crystallite growth to ∼110 nm. Unlike the faceted Ni nanoparticles, the derived Ni 3 Se 4 particles display rounded morphologies without defined edges (Fig. 4 c). High-resolution imaging (Fig. 4 d) confirms a 0.269 nm lattice spacing corresponding to the (112) plane of monoclinic Ni 3 Se 4 (JCPDS 89-7162). For comparison, bare Ni 3 Se 4 nanoparticles synthesized from NiCl 2 ·6H 2 O precursors (Fig. S2) exhibit uniform ∼46.8 nm diameters without carbon confinement. N 2 physisorption isotherms (Fig. 5 a) quantify the specific surface area and mesoporous characteristics of 0.4-Ni/C and Ni 3 Se 4 /C composites. Both materials exhibit Type IV hysteresis loops, confirming well-defined mesoporosity within the 2–40 nm range. BET surface area measurements reveal 188.2 m 2 g − 1 for 0.4-Ni/C versus 92.8 m 2 g − 1 for Ni 3 Se 4 /C. This 50.7% reduction correlates directly with mass increase during nickel selenization and subsequent crystallite densification. Figure 5 b compares the mesoporous architectures of 0.4-Ni/C and Ni 3 Se 4 /C composites, revealing analogous pore diameter distributions concentrated within 2–10 nm for both materials. The chemical composition of Ni 3 Se 4 /C composite is investigated by XPS spectrum and TGA analysis, as shown in Fig. 6 . The deconvoluted C 1s spectrum (Fig. 6 a) exhibits two components at 284.6 eV (C-C, carbon framework) and 285.9 eV (C-O, residual citrate groups). Selenium 3d regions (Fig. 6 b) display characteristic doublet peaks at 54.1 eV (3d 5/2 ) and 55.0 eV (3d 3/2 ), alongside a prominent SeOₓ signature at 58.9 eV [ 20 , 22 – 25 ]. Ni 2p spectra reveal spin-orbit split doublets (2p 3/2 : 855.5 eV, 2p 1/2 : 872.9 eV) consistent with Ni(OH) 2 references (NIST database), confirming Ni 2+ oxidation state. Furthermore, two shakeup satellites (denoted as Sat.) also can be found, resulting from the unfilled Ni 2+ 3d orbits (Fig. 6 c). According above analysis, the Ni may be having a chemical valence of + 2 within Ni 3 Se 4 due to its stable 3d electron structure of t 2g 6 e g 2 in octahedral field of NiO 6 , and the selenium possesses an average chemical valence of -1.5, originating from equal distribution of Se 2− and Se 2 2− . TGA curves of bare Ni 3 Se 4 or Ni 3 Se 4 /C composite are revealed in Fig. 6 d. A phase transformation from Ni 3 Se 4 to NiO x and combustion of carbon component happens for Ni 3 Se 4 /C accompanying with the increased temperature. The weight loss of Ni 3 Se 4 /C from 200 o C to 650 o C is 68.6%, while it is 57.1% for bare Ni 3 Se 4 under same condition, and the carbon content should be ~ 30.6 wt% according to above data. Figure 7 details the electrochemical performance of the Ni 3 Se 4 /C composite as an anode material for LIBs. Delivering initial discharge and charge capacities of 942.7 mAh g − 1 and 589.1 mAh g − 1 respectively at 0.2 A g − 1 , the Ni 3 Se 4 /C composite exhibits a Coulombic efficiency (CE) of 62.5%. Under identical conditions, the uncoated Ni 3 Se 4 nanoparticles demonstrate superior performance, achieving a discharge capacity of 1094.2 mAh g − 1 and a CE of 70.2% (Fig. 7 a). The incorporation of carbon within the composite structure lowers the relative concentration of the electrochemically active Ni 3 Se 4 phase and enhances the material's specific surface area. These combined effects appear detrimental to the initial electrochemical behavior, leading to the observed lower CE and increased irreversible capacity for the Ni 3 Se 4 /C composite compared to the bare nanoparticles. Figure 7 b directly compares the cycling stability of bare Ni3Se4 nanoparticles and the Ni 3 Se 4 /C composite at a current density of 200 mA g − 1 . Initial testing revealed a second-cycle discharge capacity of 621.3 mAh g − 1 for the Ni 3 Se 4 /C anode. More remarkably, this composite maintained 586.2 mAh g − 1 after 100 complete cycles, achieving a capacity retention of 94.4%. Conversely, bare Ni 3 Se 4 suffered severe capacity loss, particularly pronounced during cycles 20 to 40. This specific degradation pattern aligns with published behavior observed in other metal selenide electrodes [ 29 , 30 ]. Ultimately, the bare material retained only 58.1 mAh g − 1 by the 100th cycle. These findings underscore the superior cycling performance of the composite compared to the pure phase material. This significant enhancement in long-term stability arises from two key structural features integrated within the Ni 3 Se 4 design: (1) Carbon nanoplates encompassing the active Ni 3 Se 4 nanoparticles serve to mitigate large volume changes inherent in lithium cycling processes; and (2) The Ni 3 Se 4 phase itself, characterized by an open architecture and restricted particle growth, intrinsically resists electrode disintegration. Together, these mechanisms prevent the type of rapid, severe capacity deterioration evident in the unmodified Ni 3 Se 4 [ 12 – 14 ]. Cyclic voltammetry (CV) was employed to investigate the electrochemical characteristics of the Ni 3 Se 4 /C composite (Fig. 7 c). This analysis revealed close similarities between the electrochemical behavior of Ni 3 Se 4 and NiSe. During the initial discharge, three cathodic peak marked a, b and c can be found. The former two can be ascribed to the reduction of Ni 3 Se 4 and resultant Se − [ 20 , 22 – 25 ]: Ni 3 Se 4 + 6Li + + 6e − = 3Ni + 2Li 3 Se 2 (the reduction of Ni 2+ ) Li 3 Se 2 + Li + + e − = 2Li 2 Se (the reduction of Li 3 Se 2 ) The peak c is due to the formation of solid electrolyte interface (SEI) film. In the charge and subsequent cycle, two pairs of cathodic/anodic peaks (denoted by a, a’, b and b’ ) located in 2.34/1.68 and 2.01/1.34 V can be clearly presented, indicating the reversible transformation between nickle selenides and lithium selenides. Comparative electrochemical impedance spectroscopy was conducted on pristine Ni 3 Se 4 /C and unmodified Ni 3 Se 4 electrodes. Characteristic Nyquist spectra exhibit two distinct regions: a high-frequency semicircle corresponding to charge-transfer resistance (R ct ) at the electrode-electrolyte interface, followed by a low-frequency sloped line indicative of Warburg diffusion processes governing lithium-ion transport within the electrode matrix. The R ct of Ni 3 Se 4 /C and Ni 3 Se 4 can be measured as 31.8 and 58.0 Ω from inserted equivalent circuit, suggesting the introduction of carbon nanoplate and distribution of Ni 3 Se 4 nanoparticles can provide fast charge transfer process. Electrode processes typically involve dual contributions: faradaic charge transfer (cation intercalation) and non-faradaic double-layer effects. These mechanisms are quantitatively distinguished through the power-law relationship: \({{\text{i}}_{\text{p}}}{\text{ = a}}{{\text{v}}^{\text{b}}}\) , its derives \({\text{Log }}{{\text{i}}_{\text{p}}}{\text{ = bLogv + Loga}}\) Where i p denotes peak current and v represents scan rate. The coefficient b determines reaction kinetics: values approaching 1 signify capacitive-dominated behavior, while b ≈ 0.5 indicates diffusion-controlled processes [ 29 , 30 ]. Figure 8 b displays the linear fits obtained from the log(iₚ) vs. log(v) data for redox peaks 1–4 identified in the CV profiles (Fig. 8 a). Slope values (b-values) of 0.54, 0.57, 0.70, and 0.65 respectively demonstrate that Ni 3 Se 4 /C energy storage operates through a dual mechanism combining diffusion-limited and pseudocapacitive processes. Extended cycling endurance and rate tolerance represent critical anode evaluation metrics. The Ni 3 Se 4 /C composite demonstrates exceptional structural robustness during 500-cycle testing at 1 A g − 1 (Fig. 8 c), maintaining consistent capacity retention throughout prolonged operation.The discharge capacity decays at beginning 100 cycles, and continuously increases for subsequent 400 cycles. A discharge capacity of 652.8 mAh g − 1 can be reached after 500 cycles. From inserted discharge charge curves, it can be clearly presented that a charge plateau nearby 2.0 V disappear upon increased cycles, suggesting the energy storage transformation from diffusion control to capacity control, and improved nonfaradaic contribution leads to the increase of discharge capacity. Rate capability of Ni 3 Se 4 /C composite is revealed in Fig. 7 d. Discharge capacity inversely correlates with current density, as evidenced by the Ni 3 Se 4 /C composite’s performance: 567.3 mAh g − 1 (0.5 A g − 1 ), 509.2 mAh g − 1 (1 A g − 1 ), and 375.5 mAh g − 1 under extreme 5 A g − 1 cycling. Subsequent restoration to 0.2 A g − 1 achieves 615.1 mAh g − 1 , demonstrating superior kinetic stability and rate resilience for anode materials. Nickel selenides (NiSe 2 , NiSe) demonstrate sodium storage capability as documented [ 20 , 22 – 25 ], a property extended to Ni 3 Se 4 /C composites. Figure 9 a compares initial sodiation/desodiation profiles of Ni 3 Se 4 /C and unmodified Ni 3 Se 4 nanoparticles (0.2 A g − 1 ). The composite delivers initial discharge/charge capacities of 497.4/368.7 mAh g − 1 with 74.1% Coulombic efficiency - significantly lower than lithium-ion performance. This reduced efficiency suggests greater irreversible losses during SEI formation in sodium systems. Unmodified Ni 3 Se 4 exhibits higher initial capacities (663.2/488.6 mAh g − 1 ), consistent with literature values for NiSe/NiSe 2 [ 20 , 22 – 25 ]. Cycling stability analysis (Fig. 8 b) reveals progressive capacity fading in Ni 3 Se 4 /C during initial 60 cycles, stabilizing thereafter to retain 167.9 mAh g − 1 (42.8% retention) after 100 cycles. By contrast, bare Ni 3 Se 4 suffers severe structural degradation, retaining merely 35.8 mAh g − 1 after equivalent cycling. These findings establish that neither pristine nor carbon-modified Ni 3 Se 4 meets practical requirements for sodium-ion anodes due to intrinsic kinetic limitations. In Fig. 8 c, initial three cycle CV curves of Ni 3 Se 4 /C composite are shown. After the first cycle, the CV curve is similar with its pattern as LIBs anode (Fig. 7 c), and two pairs of anodic/cathodic peaks marked by a/a’ and b/b’ can be observed, indicating the electrochemical process for sodium storage is same as its lithium storage. In a comparative image (Fig. S3), it is found that the oxidation peaks b’ shifts to low voltage direction for ~ 0.3 V, which is due to the standard electrode potentials of sodium (i.e., -2.714 V vs. H + /H 2 ) is ~ 0.3 V higher than that of lithium (i.e., -3.045 V vs. H + /H 2 ). Figure 8 d evaluates the rate-dependent electrochemical behavior of the Ni 3 Se 4 /C composite. This anode demonstrates exceptional rate retention, sustaining 188.2 mAh g − 1 at 5 A g − 1 - equivalent to 76.3% of its baseline capacity at 0.2 A g − 1 . Conclusion A templated hydrothermal synthesis utilizing Ni/C precursors yields Ni 3 Se 4 /C composites with monitored formation pathways. The architecture features ~ 110 nm Ni 3 Se 4 nanoparticles uniformly embedded within carbon nanoplates. This dual-role carbon matrix provides simultaneous electron highways and spatial confinement chambers, addressing critical challenges of metal selenides in battery applications. As lithium-ion battery anodes, these composites deliver exceptional charge storage metrics: retaining 586.2 mAh g − 1 after 100 cycles (0.2 A g − 1 ) and sustaining 375.5 mAh g − 1 at 5 A g − 1 . The precisely engineered carbon encapsulation strategy represents a significant advancement in stabilizing conversion-type anode materials under high-rate cycling conditions. Carbon integration significantly enhances cycling durability while reducing charge-transfer resistance via EIS analysis. Conversely, sodium-ion storage performance remains suboptimal (167.9 mAh g − 1 retention after 100 cycles), highlighting the critical need for ion-transport optimization in larger Na + systems. Future compositional modifications could improve sodium storage capabilities through defect engineering or interlayer spacing control. Declarations Author contribution Dr. Zhao wrote the main manuscript text, prepared all of Figure, and reviewed the manuscript. Mr. Fan and Mr. Hu provided assistance with the analysis for Figures 6 and 7, and helped to revised the manuscript. Dr. Tu Provided the idea and design for the experiment. Acknowledgements and Funding Research funding was granted by the Natural Science Foundation of Fujian Province under Award Numbers 2021J011094, 2023J01983, and 2023J01984. Conflict of Interest No potential conflicts of interest exist among the authors. References Hu Z, Liu QN, Chou SL, Dou SX (2018) Advances and Challenges in Metal Sulfides/Selenides for Next-Generation Rechargeable Sodium-Ion Batteries. Adv Energy Mater 29: 1700606. https://doi.org/10.1002/adma.201700606 Desai R, Jadhav V, Patil P, Dalavi D (2024) Recent advances in hydrothermally and solvothermally grown Co 3 O 4 nanostructures for electrochemical energy storage (EES) applications: a brief review. Mater Adv 5: 920-960. https://doi.org/10.1039/D3MA00806A Wu C, Yang YR, Zhang YH, Xu H, Wu XQ, Chou SL (2024) Hard carbon for sodium-ion batteries: progress, strategies and future perspective. Chem Sci 15: 6244-6268. https://doi.org/10.1039/d4sc00734d Palchoudhury S, Ramasamy K, Han JC, Chen P, Gupta A (2023) Transition metal chalcogenides for next-generation energy storage. Nanoscale Adv 5: 2724-2742. https://doi.org/10.1039/D2NA00944G Zhang WX, Li Z, He C, Ning XH (2024) NiS 2 @MWCNTs as a promising anode material for lithium and sodium-ion batteries with superior cycling stability. J Alloys Compd 15: 172669.https://doi.org/10.1016/j.jallcom.2023.172669 Bi R, Zeng C, Huang HW, Wang XP, Zhang L (2018) Metal–organic frameworks derived hollow NiS 2 spheres encased in graphene layers for enhanced sodium-ion storage. J Mater Chem A 6: 14077-14082. https://doi.org/10.1039/c8ta05554h Zhu SH, Chen C, He P, An QY, Mai LQ (2019) Novel hollow Ni 0.33 Co 0.67 Se nanoprisms for high capacity lithium storage. Nano Res 12: 1371-1374. https://doi.org/10.1007/s12274-019-2311-1 Ali Z, Asif M, Huang XX, Tang TY, Hou YL (2018) Hierarchically Porous Fe 2 CoSe 4 Binary-Metal Selenide for Extraordinary Rate Performance and Durable Anode of Sodium-Ion Batteries. Adv Mater 30: 1802745. https://doi.org/10.1002/adma.201802745 Zhu HY, Li ZY, Xu F, Qin ZX, Sun R, Lu SJ, Zhang YF, Fan HS (2022) Ni 3 Se 4 @CoSe 2 hetero-nanocrystals encapsulated into CNT-porous carbon interpenetrating frameworks for high-performance sodium ion battery. J Colloid Interface Sci 611: 718-725. https://doi.org/10.1016/j.jcis.2021.11.175 Wang L, Bai K, Lu YQ, Mo WW, Zhang LJ (2024) Controllable hierarchical porous FeSe 2 with excellent long cycle lifespan as anode materials for sodium-ion battery. J Power Sources 1: 233913.https://doi.org/10.1016/j.jpowsour.2023.233913 Chawla A, Sudhaik A, Kumar R, Raizada P, Khan A, Singh P (2024) Recent advances in synthesis methods and surface structure manipulating strategies of copper selenide (CuSe) nanoparticles for photocatalytic environmental and energy applications. J Environ Chem Eng 12: 113125. https://doi.org/10.1016/j.jece.2024.113125 Deng ZN, Jiang H, Li CZ (2018) 2D metal chalcogenides incorporated into carbon and their assembly for energy storage applications. Small 14: 1800148. https://doi.org/10.1002/smll.201800148 Huang YX, Wang ZN, Jiang Y, Wu F, Chen RJ, et al. (2018) Hierarchical porous Co 0.85 Se@reduced graphene oxide ultrathin nanosheets with vacancy-enhanced kinetics as superior anodes for sodium-ion batteries. Nano Energy 53: 524-535. https://doi.org/10.1016/j.nanoen.2018.09.010 Indra A, Song T, Paik U (2018) Metal Organic Framework Derived Materials: Progress and Prospects for the Energy Conversion and Storage. Adv Mater 30: 1705146. https://doi.org/10.1002/adma.201705146 Li D, Zhou JS, Chen XH, Song HH (2018) Achieving ultrafast and stable Na-ion storage in FeSe 2 nanorods/graphene anodes by controlling the surface oxide. ACS Appl Mater Interface 10: 22841-22850. https://doi.org/10.1021/ acsami.8b06318 Liu JD, Liang JJ, Wang CY, Ma JM (2018) Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage. J Energy Chem 33: 160-166. https://doi.org/10.1016/j.jechem.2018.09.006 Liu TZ, Li YP, Zhao LZ, Zheng FH, Yang CH, et al. (2019) In situ fabrication of carbon-encapsulated Fe 7 X 8 (X = S, Se) for enhanced sodium storage. ACS Appl Mater Interface 11: 19040-19047 https://doi.org/10.1021/acsami.9b00500 Luo MH, Yu HX, Hu FY, Bai Y, Su J, et al. (2020) Metal selenides for high performance sodium ion batteries. Chem Eng J 380: 122557. https://doi.org/10.1016/j.cej.2019.122557 Ge P, Zhang CY, Hou HS, Wu BK. Ji XB (2018) Anions induced evolution of Co 3 X 4 (X = O, S, Se) as sodium-ion anodes: The influences of electronic structure, morphology, electrochemical property. Nano Energy 48: 617-629. https://doi.org/10.1016/j.nanoen.2018.04.018 Xu XJ, Liu J, Liu JW, Ouyang LZ, Hu RZ, Wang H, Yang LC, Zhu M (2018) A General Metal-Organic Framework (MOF)-Derived Selenidation Strategy for In Situ Carbon-Encapsulated Metal Selenides as High-Rate Anodes for Na-Ion Batteries. Adv Funct Mater, 28: 1707573. https://doi.org/10.1002/adfm.201707573 Zheng XR, Han XP, Liu H, Zhong C, Deng YD, Hu WB (2018) Controllable Synthesis of Ni x Se (0.5 ≤ x ≤ 1) Nanocrystals for Efficient Rechargeable Zinc−Air Batteries and Water Splitting. ACS Appl Mater Interfaces 10: 13675-13684. https://doi.org/10.1021/acsami.8b01651 Liu ST, Li D, Zhang GJ, Sun DD, Zhou JS, Song HH (2018) Two-dimensional NiSe 2 /N-Rich Carbon Nanocomposites Derived from Ni-Hexamine Frameworks for Superb Na-Ion Storage ACS Appl Mater Interface 10: 34193-34201. https://doi.org/10.1021/acsami.8b10635 Yang XM, Zhang JL, Wang ZG, Wang HK, Zhi CY, Wu D, Rogach A (2018) Carbon-Supported Nickel Selenide Hollow Nanowires as Advanced Anode Materials for Sodium-Ion Batteries. Small 14: 1702669. https://doi.org/10.1002/smll.201702669 Zhang ZA, Shi XD, Yang X (2016) Synthesis of core-shell NiSe/C nanospheres as anodes for lithium and sodium storage. Electrochim Acta 208: 238-243. https://doi.org/10.1016/j.electacta.2016.04.183 Ou X, Li J, Zheng FH, Wu P, Pan QC, Xiong XH, Yang CH, Liu ML (2017) In Situ X-ray Diffraction Characterization of NiSe 2 as a Promising Anode Material for Sodium ion Batteries. J Power Sources, 343: 483-491. https://doi.org/10.1016/j.jpowsour.2017.01.097 Wang J, Zhu Y, Li S, Zhai SQ, Luo JH, Mu SC, Huang YH (2022) Ni-soc-MOF derived carbon hollow sphere encapsulated Ni 3 Se 4 nanocrystals for high-rate supercapacitors. Chem Commun 58: 8846-8849. https://doi.org/10.1039/D2CC01951E Du J, Zou ZH, Liu C, Xu CL (2018) Hierarchical Fe-doped Ni 3 Se 4 ultrathin nanosheets as an efficient electrocatalyst for oxygen evolution reaction. Nanoscale 10: 5163-5170. https://doi.org/10.1039/c8nr00426a Su LW, Zhou Z, Shen PW (2012) Ni/C Hierarchical Nanostructures with Ni Nanoparticles Highly Dispersed in N-Containing Carbon Nanosheets: Origin of Li Storage Capacity. J Phys Chem C 45: 23974-23980. https://doi.org/10.1021/jp310054b Zhao CH, Shen Z, Tu FZ, Hu ZB (2020) Template directed hydrothermal synthesis of flowerlike NiSe x /C composites as lithium/sodium ion battery anodes. J Mater Sci 55: 3495-3506. https://doi.org/10.1007/s10853-019-04200-5 Fei JM, Zhao SQ, Bo XX, Xie FR, Jin HL, Lin ZQ (2023) Nano-single-crystal-constructed submicron MnCO 3 hollow spindles enabled by solid precursor transition combined Ostwald ripening in situ on graphene toward exceptional interfacial and capacitive lithium storage. Carbon Energy 5: e333. https://doi.org/10.1002/cey2.333 Additional Declarations No competing interests reported. Supplementary Files Supportinginformation.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 24 Aug, 2025 Reviews received at journal 17 Aug, 2025 Reviews received at journal 11 Aug, 2025 Reviews received at journal 09 Aug, 2025 Reviews received at journal 08 Aug, 2025 Reviewers agreed at journal 05 Aug, 2025 Reviewers agreed at journal 05 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers invited by journal 02 Aug, 2025 Editor assigned by journal 01 Aug, 2025 Submission checks completed at journal 01 Aug, 2025 First submitted to journal 31 Jul, 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-7261910","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":496277522,"identity":"7bf0756b-4e2e-45dc-908e-27da33097342","order_by":0,"name":"Chenhao Zhao","email":"","orcid":"","institution":"Longyan University","correspondingAuthor":false,"prefix":"","firstName":"Chenhao","middleName":"","lastName":"Zhao","suffix":""},{"id":496277523,"identity":"c036022b-d098-44d1-9a7b-448aa59fbb75","order_by":1,"name":"Jianming Fan","email":"","orcid":"","institution":"Longyan University","correspondingAuthor":false,"prefix":"","firstName":"Jianming","middleName":"","lastName":"Fan","suffix":""},{"id":496277524,"identity":"a6fd55c0-b75f-4156-a54c-ee02e8f9f8e0","order_by":2,"name":"Zhibiao Hu","email":"","orcid":"","institution":"Longyan University","correspondingAuthor":false,"prefix":"","firstName":"Zhibiao","middleName":"","lastName":"Hu","suffix":""},{"id":496277525,"identity":"b2e3a86f-9f4d-4a32-831e-b21583caf3eb","order_by":3,"name":"Fengzhang Tu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYBACfvbGhgMJBhL1/OwQAcYGQlokew4ffPCgwiJBsplYLQY30pINH5ypSDA4TLQtDTlmEoltEnnGh3nMpAsYbGQ3HGB+9gCfFn6GM2AtxWYgLTMY0ow3HGAzN8BrS2MPWAvjNpAWHobDiRsO8LBJ4PULUCVYy+ZmsJb/RGg5xpZskHBGInEDM1jLAcJaJHuYDz5IqJAwljjMVmzNY5BsPPMwmxleLfzyDxsO/jCok+Nvb954m6fCTrbvePMzvFqQAAcwnEBBxUykeiBgf0C82lEwCkbBKBhRAABzE0b8whn54gAAAABJRU5ErkJggg==","orcid":"","institution":"Longyan University","correspondingAuthor":true,"prefix":"","firstName":"Fengzhang","middleName":"","lastName":"Tu","suffix":""}],"badges":[],"createdAt":"2025-07-31 11:53:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7261910/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7261910/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88614798,"identity":"5d4cb065-5d64-4a63-a958-5923738afe3f","added_by":"auto","created_at":"2025-08-08 10:30:23","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":130456,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of (a) precursor 0.4 Ni-C and (b) Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/6df13ae7877f4685109a2231.jpeg"},{"id":88614797,"identity":"bb85878a-8c97-4fd4-a23f-93ec4b76f11c","added_by":"auto","created_at":"2025-08-08 10:30:23","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":188454,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of nickel selenides (a) at different reaction times and (b) using different nickel sources.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/30b6f6ca52cf85fcdc8c3992.jpeg"},{"id":88614053,"identity":"d58a7c72-c134-4b74-969b-9f35ba799f8b","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":468068,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of (a, b) 0.4-Ni/C and (c, d) Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/d4410be2ced439f161ba0e96.jpeg"},{"id":88614051,"identity":"ca8a958b-d14c-49e5-92cd-4109dea046fc","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":466878,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of (a) 0.4-Ni/C and (b, c, d) Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite, the insert is the particle size distribution\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/765f1735749e37e8be1e31bc.jpeg"},{"id":88614059,"identity":"9e44d3df-c176-4ea4-81e5-bbadef6c7263","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":146902,"visible":true,"origin":"","legend":"\u003cp\u003e(a) N\u003csub\u003e2\u003c/sub\u003e adsorption-desorption isotherms and (b) pore size distribution of 0.4-Ni/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/f083291d305c59891546a4f6.jpeg"},{"id":88615158,"identity":"db9c361f-f604-4f0e-8c27-f78c5b4655be","added_by":"auto","created_at":"2025-08-08 10:38:23","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":241160,"visible":true,"origin":"","legend":"\u003cp\u003eXPS spectrums of (a) C\u003csub\u003e1s\u003c/sub\u003e, (b) Se\u003csub\u003e3d\u003c/sub\u003e and (c) Ni\u003csub\u003e2p\u003c/sub\u003e orbit, (d) TGA analysis of bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e or Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite\u003c/p\u003e","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/db3b82356bc674c547b39d32.jpeg"},{"id":88614067,"identity":"319b2677-4daa-499e-b004-d26ebecf62fb","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":255980,"visible":true,"origin":"","legend":"\u003cp\u003eElectrochemical performances of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composites as lithium-ion batteries anode: (a) Initial discharge-charge curves at current density of 0.2 A g\u003csup\u003e-1\u003c/sup\u003e within 0.01-2.8 V, (b) cycling stability at 0.2 A g\u003csup\u003e-1\u003c/sup\u003e, (c) initial three CV curves at scanning rate of 0.2 V s\u003csup\u003e-1\u003c/sup\u003e and (d) EIS results of fresh Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e electrode, the inserted is the equivalent circuit.\u003c/p\u003e","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/710aa6b968cf0ace456d9001.jpeg"},{"id":88614804,"identity":"81f2b92d-add9-409b-9c80-fdd6189ea317","added_by":"auto","created_at":"2025-08-08 10:30:23","extension":"jpeg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":334198,"visible":true,"origin":"","legend":"\u003cp\u003eKey electrochemical characterizations of the Ni₃Se₄/C electrode: (a) CV curves acquired over a scanning rate range of 0.1 to 0.8 mV s\u003csup\u003e-1\u003c/sup\u003e; (b) corresponding log(i\u003csub\u003ep\u003c/sub\u003e) vs. log(v) plots for analyzing peak kinetics (peaks 1-4); (c) long-term cycling stability evaluated at 1 A g\u003csup\u003e-1\u003c/sup\u003e; and (d) rate capability performance, where the inset shows representative charge/discharge profiles.\u003c/p\u003e","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/e3a149ff976d04a0771bc77b.jpeg"},{"id":88614063,"identity":"5706c70c-4c74-4e61-b136-30feb4c931e6","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"jpeg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":251456,"visible":true,"origin":"","legend":"\u003cp\u003eElectrochemical characterization of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite as sodium-ion battery anode: (a) Initial charge/discharge profiles recorded at 0.2 A g\u003csup\u003e-1\u003c/sup\u003e (voltage window: 0.01-2.8 V); (b) Cycling stability evaluated at 0.2 A g\u003csup\u003e-1\u003c/sup\u003e; (c) First three cyclic voltammetry (CV) cycles at 0.2 mV s\u003csup\u003e-1\u003c/sup\u003e scan rate; (d) Rate performance tested under incremental current densities.\u003c/p\u003e","description":"","filename":"floatimage9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/31b7fca1fcc2c9389c86e0d0.jpeg"},{"id":88616092,"identity":"af1a2c25-1199-47ce-b136-476535b5ae1f","added_by":"auto","created_at":"2025-08-08 10:46:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3189576,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/ed7b494a-7bdb-4353-b533-8bdb796bed05.pdf"},{"id":88614056,"identity":"82d86639-b8d0-48e2-afa2-66bb21461477","added_by":"auto","created_at":"2025-08-08 10:22:23","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":443778,"visible":true,"origin":"","legend":"","description":"","filename":"Supportinginformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7261910/v1/6cf265ab46980c6974deda98.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSpatially Confined Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C Architecture via Continuous Selenization: Dual-Role Carbon Matrix Enables Ultrahigh-Rate Lithium Storage and Reveals Sodium-Ion Transport Limitations\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSubstantial efforts have focused on enhancing high-capacity anodes for lithium-ion (LIBs) and sodium-ion batteries (SIBs) over the past decade [1-3]. Transition metal oxides and sulfides represent extensively researched alternative anode systems, with significant investigations addressing their synthesis protocols, electrochemical performance, and underlying storage mechanisms [4-7]. Concurrently, selenium-based compounds have emerged as viable anode candidates following rigorous recent evaluation [8-14]. Despite exhibiting moderate theoretical capacities due to inherent mass constraints, these chalcogenides demonstrate compensatory advantages through enhanced charge transfer kinetics (attributed to narrow bandgaps) and substantial interfacial charge storage contributions [8,15\u0026ndash;18]. For example, Ji et al. have made a comparative study of Co\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e, Co\u003csub\u003e3\u003c/sub\u003eS\u003csub\u003e4\u003c/sub\u003e, Co\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e as SIBs anodes. It is found that Co\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e with a close discharge capacity possesses much better cycling stability and rate capacity than two other samples [19].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMetal selenides face similar operational challenges to transition metal oxides and sulfides when deployed as battery anodes. Significant volume fluctuations during cycling frequently trigger structural degradation and rapid capacity fading. Concurrently, insufficient electroactive interfaces between electrode and electrolyte phases restrict reaction kinetics and rate performance [12-18,20]. Consequently, constructing metal selenide/carbon heterostructures represents a prevalent optimization strategy. Within this category, architectures featuring selenium-based nanoparticles encapsulated within carbon matrices have gained extensive adoption. Such core-shell configurations simultaneously enhance mass/charge transfer kinetics while accommodating volumetric stresses - collectively enabling superior cyclic endurance [12-14].\u003c/p\u003e\n\u003cp\u003eBesides the structure and morphologies design, there are also many types of metal selenides due to variable valence of selenium (-1 or -2). For example, the nickel selenides\u0026nbsp;can be synthesized as NiSe, Ni\u003csub\u003e0.85\u003c/sub\u003eSe, Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e or NiSe\u003csub\u003e2\u003c/sub\u003e accompanying with the elevated selenization degree [21], and it has been proved that the NiSe, Ni\u003csub\u003e0.85\u003c/sub\u003eSe, NiSe\u003csub\u003e2\u003c/sub\u003e can be used as LIBs or SIBs anodes [13, 22-25].\u003csup\u003e\u0026nbsp;\u003c/sup\u003eAs a\u0026nbsp;transition composition between NiSe and NiSe\u003csub\u003e2\u003c/sub\u003e(Ni\u003csub\u003e0.5\u003c/sub\u003eSe), Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e(Ni\u003csub\u003e0.75\u003c/sub\u003eSe) has been regarded as a promising electrocatalyst or supercapacitor [26, 27]. Also,\u0026nbsp;the sodium storage performances of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e are studied combing with CoSe\u003csub\u003e2\u003c/sub\u003e [9]. To our best knowledge, the electrochemical performances of bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e as LIBs or SIBs anode materials have not been reported, and it should be available to be investigated according to the performances of NiSe and NiSe\u003csub\u003e2\u003c/sub\u003e. This work reports a hydrothermal synthesis of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e and its carbon composite using distinct nickel precursors. Structural evolution, formation pathways, and electrochemical behavior as anode materials in both LIB and SIBs are systematically investigated.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cp\u003eAll precursor materials were A.R.grade and utilized without further purification. Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e and its carbon composite were synthesized through hydrothermal processing using the following protocol:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSynthesis of Ni/C nanoplates\u003c/strong\u003e: Ni/C nanoplates were synthesized via a modified sol-gel method adapted from reference [28], involving dissolution of 0.4 g NiCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO, 1.0 g citric acid, and 5.0 g urea in a binary solvent system (150 mL ethanol : 50 mL deionized water). This solution underwent constant stirring at 85\u0026nbsp;℃\u0026nbsp;until transitioning into a green hydrogel, which was subsequently dehydrated at 80\u0026nbsp;℃\u0026nbsp;for 12 hours before stepwise pyrolysis under argon atmosphere: 350\u0026nbsp;℃\u0026nbsp;(2 h) followed by 700\u0026nbsp;℃\u0026nbsp;(4 h). The resulting Ni/C composite was cooled to ambient temperature and mechanically pulverized. For comparative analysis, parallel syntheses employed stoichiometric equivalents of 0.2 g and 0.6 g NiCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO precursors, yielding designated 0.2-Ni/C and 0.6-Ni/C variants respectively, with the standard 0.4-Ni/C designation corresponding to the 0.4 g precursor formulation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSynthesis of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C hybrid:\u0026nbsp;\u003c/strong\u003e60 mg of Ni/C composite underwent ultrasonic dispersion in 10 mL deionized water. In a separate vessel, 157.9 mg selenium powder (200 mesh, Aladdin) was combined with 5 mL deionized water. Under magnetic agitation, 113.5 mg NaBH\u003csub\u003e4\u003c/sub\u003e was introduced to initiate reduction, yielding a homogeneous selenide solution. The selenide solution was transferred to the Ni/C dispersion, then sealed within a 25 mL Teflon-lined autoclave. The system was maintained at 160\u0026nbsp;℃\u0026nbsp;for 12 hours. The resultant black precipitate was vacuum-filtered, sequentially washed with deionized water and ethanol (\u0026ge;3 cycles), and vacuum-dried at 80\u0026nbsp;℃\u0026nbsp;for 12 hours.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSynthesis of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticle:\u0026nbsp;\u003c/strong\u003eThe synthetic route is consistent with the synthesis of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C except the Ni source is replaced to 0.2 g of NiCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStructural characterization\u003c/strong\u003e: Crystallographic properties of synthesized materials were determined \u003cem\u003evia\u003c/em\u003e X-ray diffraction (PANalytical X\u0026apos;Pert Powder\u003csup\u003e3\u003c/sup\u003e, Cu-K\u0026alpha; radiation at 40 kV/30 mA). Microstructural evaluation employed complementary scanning electron microscopy (Hitachi S-3400) and transmission electron microscopy (JEOL JEM-2100F) to assess morphological evolution across Ni/C, Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e, and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C specimens. Specific surface areas and pore size distributions were derived from N₂ adsorption-desorption isotherms recorded at 77 K using a Micromeritics TriStar II 3020 analyzer. Chemical composition analysis employed X-ray photoelectron spectroscopy (Thermo Escalab 250Xi), while thermal decomposition profiles were acquired via thermogravimetric analysis (Netzsch DSC 200PC) at 5\u0026nbsp;℃\u0026nbsp;min⁻\u0026sup1; under air atmosphere.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eElectrochemical characterization\u003c/strong\u003e: All electrochemical evaluations employed CR2016 coin cells configured with Li/Na counter electrodes and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e-based working electrodes. The cathode slurry was formulated by homogenizing Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite, acetylene black, and sodium alginate binder (7:2:1 mass ratio) in an agate mortar. This mixture was subsequently aqueous-slurried and doctor-bladed onto copper current collectors. After vacuum baking at 80\u0026nbsp;℃\u0026nbsp;for 5 hours, the coated foils underwent precision punching into 14 mm diameter discs. CR2016 coin cells were fabricated within an argon-saturated glovebox. Lithium foil disks (\u0026Oslash;14.5 mm) served as dual-function counter/reference electrodes in lithium-ion test cells. The electrochemical configuration employed Celgard 2400 polymeric separators paired with CapChem LBC-301 electrolyte (Shenzhen CapChem Technology Co.). For sodium ion module cells, the sodium plate with diameter of 15.0 mm self-made from sodium reagent (Sinophram) was used as both counter and reference electrodes. Polymer membrane (PFM, Foshan Jinhui) and 1 M NaCF\u003csub\u003e3\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e DEGDME solution (Nanjing Mojiesi) were used as separator and electrolyte.\u003c/p\u003e\n\u003cp\u003eGalvanostatic charge-discharge characterization for both lithium- and sodium-ion battery systems was executed on a Neware CT-3008 electrochemical platform (Shenzhen Neware Electronics Co.) using standardized testing parameters: constant current density of 0.2 A g\u003csup\u003e-1\u003c/sup\u003e within a 0.01-2.8 V operational window. Complementary cyclic voltammetric analysis employed a CH Instruments 660C workstation, with all sweeps conducted across the identical 0.01-2.8 V potential range at multiple scan rates to evaluate reaction kinetics.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003eThe Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite was synthesized hydrothermally using Ni/C as precursor material. Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea displays the XRD pattern of 0.4-Ni/C, where diffraction peaks align with metallic nickel reference data (JCPDS: 87\u0026ndash;0712). An asterisk-marked broad peak at 26\u0026deg; (2\u0026theta;) indicates carbon presence originating from citric acid carbonization.After hydrothermal selenization, the nickel selenide can be obtained, and corresponding XRD pattern is revealed in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb. It is found that all of diffraction peaks can be attributed to monoclinic Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e (JCPDS: 89-7162). The sharp diffraction peaks indicate the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e is well-crystallized. Furthermore, the wide peak sign indicating the coexistence of carbon can be retained in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb.\u003c/p\u003e\n\u003cp\u003eAs we know, the nickel selenides have several chemical compositions, such as NiSe, Ni\u003csub\u003e0.85\u003c/sub\u003eSe, Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e and NiSe\u003csub\u003e2\u003c/sub\u003e [\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e]. Among them, the pyrite-type NiSe\u003csub\u003e2\u003c/sub\u003e, a thermodynamically stable compound, can be readily obtained by gas diffusion or liquid-phase ion exchange reaction in presence of enough selenium [\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e], and the others generally are prepared by hydro/solvothermal assisted selenization method in presence of insufficient selenium or some special processes (e. g. low reaction temperature) [\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e]. In the present study, the monoclinic Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e are prepared by hydrothermal route. Considering the complexity of hydrothermal reaction, and it is necessary to specify the formation process of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e.\u003c/p\u003e\n\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$$0.85\\text{N}\\text{i} +0.7\\text{S}{\\text{e}^{2-}}+\\text{S}\\text{e}_{2}^{{2-}}{\\text{ = }}\\text{N}{\\text{i}_{0.85}}\\text{S}\\text{e}+1.7\\text{S}{\\text{e}^{2-}}$$\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eWhen the reaction time is increased to 1 h or more, some XRD characteristic peaks of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e can be found, especially a (013) diffraction peak marked by dotted line appears, and the peaks splitting of (020)/(310) diffraction peaks surrounded by frame (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eb) happens, indicating the gradually formation of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e (or described as Ni\u003csub\u003e0.75\u003c/sub\u003eSe). A continuous selenization caused by Se\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e may be responsible for the formation of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"513\" height=\"48\"\u003e\u003c/p\u003e\n\u003cp\u003eIn order to furthermore study the formation process of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e, the Ni source is replaced to 0.2 g NiCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO, and time-dependent XRD patterns of nickel selenides are shown in Fig. \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e. Initially, the Ni\u003csup\u003e2+\u003c/sup\u003e reacts with Se\u003csup\u003e2\u0026minus;\u003c/sup\u003e to form NiSe, and then the NiSe is further selnizated with Se\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e to form Ni\u003csub\u003e0.85\u003c/sub\u003eSe and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e accompanying with increased reaction time, which is similar with the formation of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e from metallic Ni (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea).\u003c/p\u003e\n\u003cp\u003eThe formation condition of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e is also studied using different Ni/C composites, 0.2-Ni/C (poor-Ni sample) and 0.6-Ni/C (rich-Ni sample), and the XRD patterns are revealed in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eb. The Ni\u003csub\u003e0.85\u003c/sub\u003eSe can be obtained from 0.6-Ni/C, while a mixture of Ni\u003csub\u003e0.75\u003c/sub\u003eSe and NiSe\u003csub\u003e2\u003c/sub\u003e can be produced from 0.2-Ni/C. According to above results, a low or high Ni/Se ratio may be difficult to obtain Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e.\u003c/p\u003e\n\u003cp\u003eMorphologies and surface structure of 0.4-Ni/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C are observed by SEM, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e. It is clear that the 0.4-Ni/C possesses morphology of nanoplate with a size of tens of microns (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea), and the nanoplate is made of carbon derived from citric acid. In a close view, some nanoparticles encapsulated into carbon nanoplate can be found (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eb). After hydrothermal selenization, the SEM images of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C are also shown in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec. The composite partially shows nanoplate-like structure, inheriting from 0.4-Ni/C, while the agglomeration turns to serious compared with precursor. In Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ed, some nanoparticles which encapsulated into carbon nanoplate can be clearly presented compared with Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eb. It is due to the transformation from metallic Ni to Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e, resulting into the particle growth.\u003c/p\u003e\n\u003cp\u003eTransmission electron microscopy (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e) reveals the morphological evolution from 0.4-Ni/C precursor to Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea distinctly shows carbon-encapsulated nickel nanoparticles (\u0026sim;48 nm) exhibiting faceted crystallographic features. Post-hydrothermal selenization preserves the nanoplate architecture (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003eb), while inducing crystallite growth to \u0026sim;110 nm. Unlike the faceted Ni nanoparticles, the derived Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e particles display rounded morphologies without defined edges (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ec). High-resolution imaging (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ed) confirms a 0.269 nm lattice spacing corresponding to the (112) plane of monoclinic Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e (JCPDS 89-7162). For comparison, bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles synthesized from NiCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO precursors (Fig. S2) exhibit uniform \u0026sim;46.8 nm diameters without carbon confinement.\u003c/p\u003e\n\u003cp\u003eN\u003csub\u003e2\u003c/sub\u003e physisorption isotherms (Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ea) quantify the specific surface area and mesoporous characteristics of 0.4-Ni/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composites. Both materials exhibit Type IV hysteresis loops, confirming well-defined mesoporosity within the 2\u0026ndash;40 nm range. BET surface area measurements reveal 188.2 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for 0.4-Ni/C versus 92.8 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C. This 50.7% reduction correlates directly with mass increase during nickel selenization and subsequent crystallite densification. Figure \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003eb compares the mesoporous architectures of 0.4-Ni/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composites, revealing analogous pore diameter distributions concentrated within 2\u0026ndash;10 nm for both materials.\u003c/p\u003e\n\u003cp\u003eThe chemical composition of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite is investigated by XPS spectrum and TGA analysis, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e. The deconvoluted C 1s spectrum (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ea) exhibits two components at 284.6 eV (C-C, carbon framework) and 285.9 eV (C-O, residual citrate groups). Selenium 3d regions (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003eb) display characteristic doublet peaks at 54.1 eV (3d\u003csub\u003e5/2\u003c/sub\u003e) and 55.0 eV (3d\u003csub\u003e3/2\u003c/sub\u003e), alongside a prominent SeOₓ signature at 58.9 eV [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e]. Ni 2p spectra reveal spin-orbit split doublets (2p\u003csub\u003e3/2\u003c/sub\u003e: 855.5 eV, 2p\u003csub\u003e1/2\u003c/sub\u003e: 872.9 eV) consistent with Ni(OH)\u003csub\u003e2\u003c/sub\u003e references (NIST database), confirming Ni\u003csup\u003e2+\u003c/sup\u003e oxidation state. Furthermore, two shakeup satellites (denoted as Sat.) also can be found, resulting from the unfilled Ni\u003csup\u003e2+\u003c/sup\u003e 3d orbits (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ec). According above analysis, the Ni may be having a chemical valence of +\u0026thinsp;2 within Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e due to its stable 3d electron structure of t\u003csub\u003e2g\u003c/sub\u003e\u003csup\u003e6\u003c/sup\u003ee\u003csub\u003eg\u003c/sub\u003e\u003csup\u003e2\u003c/sup\u003e in octahedral field of NiO\u003csub\u003e6\u003c/sub\u003e, and the selenium possesses an average chemical valence of -1.5, originating from equal distribution of Se\u003csup\u003e2\u0026minus;\u003c/sup\u003e and Se\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eTGA curves of bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e or Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite are revealed in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ed. A phase transformation from Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e to NiO\u003csub\u003ex\u003c/sub\u003e and combustion of carbon component happens for Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C accompanying with the increased temperature. The weight loss of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C from 200\u003csup\u003eo\u003c/sup\u003eC to 650\u003csup\u003eo\u003c/sup\u003eC is 68.6%, while it is 57.1% for bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e under same condition, and the carbon content should be ~\u0026thinsp;30.6 wt% according to above data.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e details the electrochemical performance of the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite as an anode material for LIBs. Delivering initial discharge and charge capacities of 942.7 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 589.1 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e respectively at 0.2 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite exhibits a Coulombic efficiency (CE) of 62.5%. Under identical conditions, the uncoated Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles demonstrate superior performance, achieving a discharge capacity of 1094.2 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and a CE of 70.2% (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ea). The incorporation of carbon within the composite structure lowers the relative concentration of the electrochemically active Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e phase and enhances the material\u0026apos;s specific surface area. These combined effects appear detrimental to the initial electrochemical behavior, leading to the observed lower CE and increased irreversible capacity for the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite compared to the bare nanoparticles.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003eb directly compares the cycling stability of bare Ni3Se4 nanoparticles and the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite at a current density of 200 mA g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Initial testing revealed a second-cycle discharge capacity of 621.3 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C anode. More remarkably, this composite maintained 586.2 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e after 100 complete cycles, achieving a capacity retention of 94.4%. Conversely, bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e suffered severe capacity loss, particularly pronounced during cycles 20 to 40. This specific degradation pattern aligns with published behavior observed in other metal selenide electrodes [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]. Ultimately, the bare material retained only 58.1 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e by the 100th cycle. These findings underscore the superior cycling performance of the composite compared to the pure phase material. This significant enhancement in long-term stability arises from two key structural features integrated within the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e design: (1) Carbon nanoplates encompassing the active Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles serve to mitigate large volume changes inherent in lithium cycling processes; and (2) The Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e phase itself, characterized by an open architecture and restricted particle growth, intrinsically resists electrode disintegration. Together, these mechanisms prevent the type of rapid, severe capacity deterioration evident in the unmodified Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e [\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eCyclic voltammetry (CV) was employed to investigate the electrochemical characteristics of the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ec). This analysis revealed close similarities between the electrochemical behavior of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e and NiSe. During the initial discharge, three cathodic peak marked \u003cem\u003ea, b\u003c/em\u003e and \u003cem\u003ec\u003c/em\u003e can be found. The former two can be ascribed to the reduction of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e and resultant Se\u003csup\u003e\u0026minus;\u003c/sup\u003e [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e]:\u003c/p\u003e\n\u003cp\u003eNi\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;6Li\u003csup\u003e+\u003c/sup\u003e + 6e\u003csup\u003e\u0026minus;\u003c/sup\u003e = 3Ni\u0026thinsp;+\u0026thinsp;2Li\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e2\u003c/sub\u003e (the reduction of Ni\u003csup\u003e2+\u003c/sup\u003e)\u003c/p\u003e\n\u003cp\u003eLi\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;Li\u003csup\u003e+\u003c/sup\u003e + e\u003csup\u003e\u0026minus;\u003c/sup\u003e = 2Li\u003csub\u003e2\u003c/sub\u003eSe (the reduction of Li\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e2\u003c/sub\u003e)\u003c/p\u003e\n\u003cp\u003eThe peak \u003cem\u003ec\u003c/em\u003e is due to the formation of solid electrolyte interface (SEI) film. In the charge and subsequent cycle, two pairs of cathodic/anodic peaks (denoted by \u003cem\u003ea, a\u0026rsquo;, b\u003c/em\u003e and \u003cem\u003eb\u0026rsquo;\u003c/em\u003e) located in 2.34/1.68 and 2.01/1.34 V can be clearly presented, indicating the reversible transformation between nickle selenides and lithium selenides.\u003c/p\u003e\n\u003cp\u003eComparative electrochemical impedance spectroscopy was conducted on pristine Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C and unmodified Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e electrodes. Characteristic Nyquist spectra exhibit two distinct regions: a high-frequency semicircle corresponding to charge-transfer resistance (R\u003csub\u003ect\u003c/sub\u003e) at the electrode-electrolyte interface, followed by a low-frequency sloped line indicative of Warburg diffusion processes governing lithium-ion transport within the electrode matrix. The R\u003csub\u003ect\u003c/sub\u003e of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C and Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e can be measured as 31.8 and 58.0 \u0026Omega; from inserted equivalent circuit, suggesting the introduction of carbon nanoplate and distribution of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles can provide fast charge transfer process.\u003c/p\u003e\n\u003cp\u003eElectrode processes typically involve dual contributions: faradaic charge transfer (cation intercalation) and non-faradaic double-layer effects. These mechanisms are quantitatively distinguished through the power-law relationship:\u003c/p\u003e\n\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({{\\text{i}}_{\\text{p}}}{\\text{ = a}}{{\\text{v}}^{\\text{b}}}\\)\u003c/span\u003e\u003c/span\u003e, its derives \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{Log }}{{\\text{i}}_{\\text{p}}}{\\text{ = bLogv + Loga}}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eWhere \u003cstrong\u003ei\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003ep\u003c/strong\u003e\u003c/sub\u003e denotes peak current and v represents scan rate. The coefficient \u003cstrong\u003eb\u003c/strong\u003e determines reaction kinetics: values approaching 1 signify capacitive-dominated behavior, while \u003cstrong\u003eb\u0026thinsp;\u0026asymp;\u0026thinsp;0.5\u003c/strong\u003e indicates diffusion-controlled processes [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]. Figure \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003eb displays the linear fits obtained from the log(iₚ) vs. log(v) data for redox peaks 1\u0026ndash;4 identified in the CV profiles (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003ea). Slope values (b-values) of 0.54, 0.57, 0.70, and 0.65 respectively demonstrate that Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C energy storage operates through a dual mechanism combining diffusion-limited and pseudocapacitive processes.\u003c/p\u003e\n\u003cp\u003eExtended cycling endurance and rate tolerance represent critical anode evaluation metrics. The Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite demonstrates exceptional structural robustness during 500-cycle testing at 1 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003ec), maintaining consistent capacity retention throughout prolonged operation.The discharge capacity decays at beginning 100 cycles, and continuously increases for subsequent 400 cycles. A discharge capacity of 652.8 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e can be reached after 500 cycles. From inserted discharge charge curves, it can be clearly presented that a charge plateau nearby 2.0 V disappear upon increased cycles, suggesting the energy storage transformation from diffusion control to capacity control, and improved nonfaradaic contribution leads to the increase of discharge capacity. Rate capability of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite is revealed in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ed. Discharge capacity inversely correlates with current density, as evidenced by the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite\u0026rsquo;s performance: 567.3 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (0.5 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), 509.2 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (1 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), and 375.5 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e under extreme 5 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e cycling. Subsequent restoration to 0.2 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e achieves 615.1 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, demonstrating superior kinetic stability and rate resilience for anode materials.\u003c/p\u003e\n\u003cp\u003eNickel selenides (NiSe\u003csub\u003e2\u003c/sub\u003e, NiSe) demonstrate sodium storage capability as documented [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e], a property extended to Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composites. Figure \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003ea compares initial sodiation/desodiation profiles of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C and unmodified Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles (0.2 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). The composite delivers initial discharge/charge capacities of 497.4/368.7 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with 74.1% Coulombic efficiency - significantly lower than lithium-ion performance. This reduced efficiency suggests greater irreversible losses during SEI formation in sodium systems. Unmodified Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e exhibits higher initial capacities (663.2/488.6 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), consistent with literature values for NiSe/NiSe\u003csub\u003e2\u003c/sub\u003e [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eCycling stability analysis (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003eb) reveals progressive capacity fading in Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C during initial 60 cycles, stabilizing thereafter to retain 167.9 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (42.8% retention) after 100 cycles. By contrast, bare Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e suffers severe structural degradation, retaining merely 35.8 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e after equivalent cycling. These findings establish that neither pristine nor carbon-modified Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e meets practical requirements for sodium-ion anodes due to intrinsic kinetic limitations.\u003c/p\u003e\n\u003cp\u003eIn Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003ec, initial three cycle CV curves of Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite are shown. After the first cycle, the CV curve is similar with its pattern as LIBs anode (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ec), and two pairs of anodic/cathodic peaks marked by a/a\u0026rsquo; and b/b\u0026rsquo; can be observed, indicating the electrochemical process for sodium storage is same as its lithium storage. In a comparative image (Fig. S3), it is found that the oxidation peaks b\u0026rsquo; shifts to low voltage direction for ~\u0026thinsp;0.3 V, which is due to the standard electrode potentials of sodium (i.e., -2.714 V \u003cem\u003evs.\u003c/em\u003e H\u003csup\u003e+\u003c/sup\u003e/H\u003csub\u003e2\u003c/sub\u003e) is ~\u0026thinsp;0.3 V higher than that of lithium (i.e., -3.045 V \u003cem\u003evs.\u003c/em\u003e H\u003csup\u003e+\u003c/sup\u003e/H\u003csub\u003e2\u003c/sub\u003e). Figure \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003ed evaluates the rate-dependent electrochemical behavior of the Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composite. This anode demonstrates exceptional rate retention, sustaining 188.2 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e at 5 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e - equivalent to 76.3% of its baseline capacity at 0.2 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eA templated hydrothermal synthesis utilizing Ni/C precursors yields Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e/C composites with monitored formation pathways. The architecture features\u0026thinsp;~\u0026thinsp;110 nm Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles uniformly embedded within carbon nanoplates. This dual-role carbon matrix provides simultaneous electron highways and spatial confinement chambers, addressing critical challenges of metal selenides in battery applications. As lithium-ion battery anodes, these composites deliver exceptional charge storage metrics: retaining 586.2 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e after 100 cycles (0.2 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and sustaining 375.5 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e at 5 A g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The precisely engineered carbon encapsulation strategy represents a significant advancement in stabilizing conversion-type anode materials under high-rate cycling conditions. Carbon integration significantly enhances cycling durability while reducing charge-transfer resistance via EIS analysis. Conversely, sodium-ion storage performance remains suboptimal (167.9 mAh g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e retention after 100 cycles), highlighting the critical need for ion-transport optimization in larger Na\u003csup\u003e+\u003c/sup\u003e systems. Future compositional modifications could improve sodium storage capabilities through defect engineering or interlayer spacing control.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr. Zhao wrote the main manuscript text, prepared all of Figure, and reviewed the manuscript. Mr. Fan and Mr. Hu provided assistance with the analysis for Figures 6 and 7, and helped to revised the manuscript. Dr. Tu Provided the idea and design for the experiment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements and Funding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResearch funding was granted by the Natural Science Foundation of Fujian Province under Award Numbers 2021J011094, 2023J01983, and 2023J01984.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo potential conflicts of interest exist among the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHu Z, Liu QN, Chou SL, Dou SX (2018) Advances and Challenges in Metal Sulfides/Selenides for Next-Generation Rechargeable Sodium-Ion Batteries. Adv Energy Mater 29: 1700606. https://doi.org/10.1002/adma.201700606\u003c/li\u003e\n\u003cli\u003eDesai R, Jadhav V, Patil P, Dalavi D (2024) Recent advances in hydrothermally and solvothermally grown Co\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanostructures for electrochemical energy storage (EES) applications: a brief review. Mater Adv 5: 920-960. https://doi.org/10.1039/D3MA00806A\u003c/li\u003e\n\u003cli\u003eWu C, Yang YR, Zhang YH, Xu H, Wu XQ, Chou SL (2024) Hard carbon for sodium-ion batteries: progress, strategies and future perspective. Chem Sci 15: 6244-6268. https://doi.org/10.1039/d4sc00734d\u003c/li\u003e\n\u003cli\u003ePalchoudhury S, Ramasamy K, Han JC, Chen P, Gupta A (2023) Transition metal chalcogenides for next-generation energy storage. Nanoscale Adv 5: 2724-2742. https://doi.org/10.1039/D2NA00944G\u003c/li\u003e\n\u003cli\u003eZhang WX, Li Z, He C, Ning XH (2024) NiS\u003csub\u003e2\u003c/sub\u003e @MWCNTs as a promising anode material for lithium and sodium-ion batteries with superior cycling stability. J Alloys Compd 15: 172669.https://doi.org/10.1016/j.jallcom.2023.172669\u003c/li\u003e\n\u003cli\u003eBi R, Zeng C, Huang HW, Wang XP, Zhang L (2018) Metal\u0026ndash;organic frameworks derived hollow NiS\u003csub\u003e2\u003c/sub\u003e spheres encased in graphene layers for enhanced sodium-ion storage. J Mater Chem A 6: 14077-14082. https://doi.org/10.1039/c8ta05554h\u003c/li\u003e\n\u003cli\u003eZhu SH, Chen C, He P, An QY, Mai LQ (2019) Novel hollow Ni\u003csub\u003e0.33\u003c/sub\u003eCo\u003csub\u003e0.67\u003c/sub\u003eSe nanoprisms for high capacity lithium storage. Nano Res 12: 1371-1374. https://doi.org/10.1007/s12274-019-2311-1\u003c/li\u003e\n\u003cli\u003eAli Z, Asif M, Huang XX, Tang TY, Hou YL (2018) Hierarchically Porous Fe\u003csub\u003e2\u003c/sub\u003eCoSe\u003csub\u003e4 \u003c/sub\u003eBinary-Metal Selenide for Extraordinary Rate Performance and Durable Anode of Sodium-Ion Batteries. Adv Mater 30: 1802745. https://doi.org/10.1002/adma.201802745 \u003c/li\u003e\n\u003cli\u003eZhu HY, Li ZY, Xu F, Qin ZX, Sun R, Lu SJ, Zhang YF, Fan HS (2022) Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e@CoSe\u003csub\u003e2\u003c/sub\u003e hetero-nanocrystals encapsulated into CNT-porous carbon interpenetrating frameworks for high-performance sodium ion battery. J Colloid Interface Sci 611: 718-725. https://doi.org/10.1016/j.jcis.2021.11.175\u003c/li\u003e\n\u003cli\u003eWang L, Bai K, Lu YQ, Mo WW, Zhang LJ (2024) Controllable hierarchical porous FeSe\u003csub\u003e2\u003c/sub\u003e with excellent long cycle lifespan as anode materials for sodium-ion battery. J Power Sources 1: 233913.https://doi.org/10.1016/j.jpowsour.2023.233913\u003c/li\u003e\n\u003cli\u003eChawla A, Sudhaik A, Kumar R, Raizada P, Khan A, Singh P (2024) Recent advances in synthesis methods and surface structure manipulating strategies of copper selenide (CuSe) nanoparticles for photocatalytic environmental and energy applications. J Environ Chem Eng 12: 113125. https://doi.org/10.1016/j.jece.2024.113125\u003c/li\u003e\n\u003cli\u003eDeng ZN, Jiang H, Li CZ (2018) 2D metal chalcogenides incorporated into carbon and their assembly for energy storage applications. Small 14: 1800148. https://doi.org/10.1002/smll.201800148\u003c/li\u003e\n\u003cli\u003eHuang YX, Wang ZN, Jiang Y, Wu F, Chen RJ, et al. (2018) Hierarchical porous Co\u003csub\u003e0.85\u003c/sub\u003eSe@reduced graphene oxide ultrathin nanosheets with vacancy-enhanced kinetics as superior anodes for sodium-ion batteries. Nano Energy 53: 524-535. https://doi.org/10.1016/j.nanoen.2018.09.010 \u003c/li\u003e\n\u003cli\u003eIndra A, Song T, Paik U (2018) Metal Organic Framework Derived Materials: Progress and Prospects for the Energy Conversion and Storage. Adv Mater 30: 1705146. https://doi.org/10.1002/adma.201705146\u003c/li\u003e\n\u003cli\u003eLi D, Zhou JS, Chen XH, Song HH (2018) Achieving ultrafast and stable Na-ion storage in FeSe\u003csub\u003e2\u003c/sub\u003e nanorods/graphene anodes by controlling the surface oxide. ACS Appl Mater Interface 10: 22841-22850. https://doi.org/10.1021/ acsami.8b06318\u003c/li\u003e\n\u003cli\u003eLiu JD, Liang JJ, Wang CY, Ma JM (2018) Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage. J Energy Chem 33: 160-166. https://doi.org/10.1016/j.jechem.2018.09.006\u003c/li\u003e\n\u003cli\u003eLiu TZ, Li YP, Zhao LZ, Zheng FH, Yang CH, et al. (2019) In situ fabrication of carbon-encapsulated Fe\u003csub\u003e7\u003c/sub\u003eX\u003csub\u003e8\u003c/sub\u003e (X = S, Se) for enhanced sodium storage. ACS Appl Mater Interface 11: 19040-19047 https://doi.org/10.1021/acsami.9b00500\u003c/li\u003e\n\u003cli\u003eLuo MH, Yu HX, Hu FY, Bai Y, Su J, et al. (2020) Metal selenides for high performance sodium ion batteries. Chem Eng J 380: 122557. https://doi.org/10.1016/j.cej.2019.122557\u003c/li\u003e\n\u003cli\u003eGe P, Zhang CY, Hou HS, Wu BK. Ji XB (2018) Anions induced evolution of Co\u003csub\u003e3\u003c/sub\u003eX\u003csub\u003e4\u003c/sub\u003e (X = O, S, Se) as sodium-ion anodes: The influences of electronic structure, morphology, electrochemical property. Nano Energy 48: 617-629. https://doi.org/10.1016/j.nanoen.2018.04.018\u003c/li\u003e\n\u003cli\u003eXu XJ, Liu J, Liu JW, Ouyang LZ, Hu RZ, Wang H, Yang LC, Zhu M (2018) A General Metal-Organic Framework (MOF)-Derived Selenidation Strategy for In Situ Carbon-Encapsulated Metal Selenides as High-Rate Anodes for Na-Ion Batteries. Adv Funct Mater, 28: 1707573. https://doi.org/10.1002/adfm.201707573\u003c/li\u003e\n\u003cli\u003eZheng XR, Han XP, Liu H, Zhong C, Deng YD, Hu WB (2018) Controllable Synthesis of Ni\u003csub\u003ex\u003c/sub\u003eSe (0.5 \u0026le; x \u0026le; 1) Nanocrystals for Efficient Rechargeable Zinc\u0026minus;Air Batteries and Water Splitting. ACS Appl Mater Interfaces 10: 13675-13684. https://doi.org/10.1021/acsami.8b01651\u003c/li\u003e\n\u003cli\u003eLiu ST, Li D, Zhang GJ, Sun DD, Zhou JS, Song HH (2018) Two-dimensional NiSe\u003csub\u003e2\u003c/sub\u003e/N-Rich Carbon Nanocomposites Derived from Ni-Hexamine Frameworks for Superb Na-Ion Storage ACS Appl Mater Interface 10: 34193-34201. https://doi.org/10.1021/acsami.8b10635\u003c/li\u003e\n\u003cli\u003eYang XM, Zhang JL, Wang ZG, Wang HK, Zhi CY, Wu D, Rogach A (2018) Carbon-Supported Nickel Selenide Hollow Nanowires as Advanced Anode Materials for Sodium-Ion Batteries. Small 14: 1702669. https://doi.org/10.1002/smll.201702669\u003c/li\u003e\n\u003cli\u003eZhang ZA, Shi XD, Yang X (2016) Synthesis of core-shell NiSe/C nanospheres as anodes for lithium and sodium storage. Electrochim Acta 208: 238-243. https://doi.org/10.1016/j.electacta.2016.04.183\u003c/li\u003e\n\u003cli\u003eOu X, Li J, Zheng FH, Wu P, Pan QC, Xiong XH, Yang CH, Liu ML (2017) In Situ X-ray Diffraction Characterization of NiSe\u003csub\u003e2\u003c/sub\u003e as a Promising Anode Material for Sodium ion Batteries. J Power Sources, 343: 483-491. https://doi.org/10.1016/j.jpowsour.2017.01.097\u003c/li\u003e\n\u003cli\u003eWang J, Zhu Y, Li S, Zhai SQ, Luo JH, Mu SC, Huang YH (2022) Ni-soc-MOF derived carbon hollow sphere encapsulated Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4 \u003c/sub\u003enanocrystals for high-rate supercapacitors. Chem Commun 58: 8846-8849. https://doi.org/10.1039/D2CC01951E\u003c/li\u003e\n\u003cli\u003eDu J, Zou ZH, Liu C, Xu CL (2018) Hierarchical Fe-doped Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e ultrathin nanosheets as an efficient electrocatalyst for oxygen evolution reaction. Nanoscale 10: 5163-5170. https://doi.org/10.1039/c8nr00426a\u003c/li\u003e\n\u003cli\u003eSu LW, Zhou Z, Shen PW (2012) Ni/C Hierarchical Nanostructures with Ni Nanoparticles Highly Dispersed in N-Containing Carbon Nanosheets: Origin of Li Storage Capacity. J Phys Chem C 45: 23974-23980. https://doi.org/10.1021/jp310054b\u003c/li\u003e\n\u003cli\u003eZhao CH, Shen Z, Tu FZ, Hu ZB (2020) Template directed hydrothermal synthesis of flowerlike NiSe\u003csub\u003ex\u003c/sub\u003e/C composites as lithium/sodium ion battery anodes. J Mater Sci 55: 3495-3506. https://doi.org/10.1007/s10853-019-04200-5\u003c/li\u003e\n\u003cli\u003eFei JM, Zhao SQ, Bo XX, Xie FR, Jin HL, Lin ZQ (2023) Nano-single-crystal-constructed submicron MnCO\u003csub\u003e3\u003c/sub\u003e hollow spindles enabled by solid precursor transition combined Ostwald ripening in situ on graphene toward exceptional interfacial and capacitive lithium storage. Carbon Energy 5: e333. https://doi.org/10.1002/cey2.333\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Ni3Se4/C hybrid, Template-directed hydrothermal synthesis, Progressive selenization, Lithium/Sodium ion storage, Carbon-encapsulated architecture","lastPublishedDoi":"10.21203/rs.3.rs-7261910/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7261910/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNickel selenides' structural diversity offers promising avenues for advanced battery anodes, yet their practical implementation faces persistent challenges of structural instability and sluggish kinetics. Addressing these limitations, we pioneer a spatially confined architecture through template-directed hydrothermal synthesis: ~48 nm Ni\u003csub\u003e3\u003c/sub\u003eSe\u003csub\u003e4\u003c/sub\u003e nanoparticles uniformly encapsulated within conductive carbon nanoplates. Time-dependent XRD analysis confirms continuous selenization-driven phase evolution, while XPS/TGA verify the composite (30.6 wt% carbon) comprises Ni\u003csup\u003e2+\u003c/sup\u003e, Se\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e and Se\u003csup\u003e2-\u003c/sup\u003e species. This dual-role design - where carbon simultaneously serves as electron highway and volume-change buffer - enables breakthrough lithium storage performance: 586.2 mAh g\u003csup\u003e-1\u003c/sup\u003e after 100 cycles (0.2 A g\u003csup\u003e-1\u003c/sup\u003e) with exceptional 375.5 mAh g\u003csup\u003e-1\u003c/sup\u003e retention at ultrahigh 5 A g\u003csup\u003e-1\u003c/sup\u003e. Electrochemical analysis demonstrates carbon spacers reduce charge-transfer resistance by \u0026gt;40% versus bare counterparts. The strategically engineered interface provides critical insights for stabilizing conversion-type anodes, though sodium storage remains challenging (167.9 mAh g\u003csup\u003e-1\u003c/sup\u003e after 100 cycles), highlighting fundamental differences in ion storage mechanisms that guide future material design.\u003c/p\u003e","manuscriptTitle":"Spatially Confined Ni3Se4/C Architecture via Continuous Selenization: Dual-Role Carbon Matrix Enables Ultrahigh-Rate Lithium Storage and Reveals Sodium-Ion Transport Limitations","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-08 10:22:18","doi":"10.21203/rs.3.rs-7261910/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-24T12:03:17+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-17T23:51:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-12T01:07:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-10T01:44:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-08T20:49:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"254003156617929892088074708877099786045","date":"2025-08-06T01:25:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"260425047751750700172924477551754256567","date":"2025-08-05T12:56:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"18071442895059280499871037539301822632","date":"2025-08-04T02:38:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"337303390023503977802504921351481664198","date":"2025-08-04T00:57:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"16002199588417555342157859457838340440","date":"2025-08-03T17:25:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"211671780773068727747227315379578447757","date":"2025-08-03T15:45:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-02T20:13:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-01T08:04:25+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-01T08:02:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"Ionics","date":"2025-07-31T11:46:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"8071d2e0-23b1-44f7-b9f7-071fa297f3d1","owner":[],"postedDate":"August 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-10-07T21:08:28+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-08 10:22:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7261910","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7261910","identity":"rs-7261910","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}