Electrode Materials For Energy Storage Research Articles

High-performance α-Fe2O3 nano cubes as anode for supercapacitors

Abundant availability, high theoretical specific capacitance and low cost of transition metal oxides such as iron oxides, make them attractive as electrode materials for energy storage. In order to achieve improved performance, high conductivity, shorter ion-diffusion path, and faster ion accessibility, rational design of morphology of electrode material is highly desirable. We have successfully synthesized mesoporous α-Fe2O3 nanocubes to achieve high specific capacitance and better retention. The as-prepared and annealed α-Fe2O3 nanocubes show high reversible redox activity along with good thermodynamic stability. These nanostructure give rise to high specific capacitance and ~90 % of the capacitance can be retained even after 1000 redox cycles, suggesting good cyclic stability. The electrochemical performance of mesoporous α-Fe2O3 nanocubes is attributed to the morphological features, which results in efficient K+ ion transport into the pores. A two electrode α-Fe2O3//NiO device is fabricated, which shows excellent power and energy density of ∼627 W/kg and ∼23.32 Wh/kg, respectively. Our work demonstrates that 3D nanoporous α-Fe2O3 electrodes forms promising material system as anode for improved charge storage performance.

Activated biomass-derived 3-dimensional porous graphene-like carbon for high-performance energy storage electrode materials

This article reports studies on the fabrication of active material for supercapacitor electrodes, from 3D porous graphene-like carbon (GLC), synthesized by carbonization from coffee waste (CW) and tea waste (TW) at 550 °C, followed by thermochemical activation in KOH at 850 °C in a quartz tubular furnace. The microstructure of coffee and tea waste shows the form of micro- and mesopores during carbonization and further chemical activation forms hierarchically highly porous 3D graphene-like carbon. GLC-CW exhibited a higher specific surface area (SSA) of 3486 m2/g according to the Brunauer-Emmett-Teller (BET) method, compared to GLC-TW, which had an SSA of 2407 m2/g. These results highlight the effectiveness of graphene-like carbon derived from coffee and tea waste, demonstrating its potential as a promising material for high-capacity supercapacitors. The electrochemical characteristics of the assembled supercapacitors using GLC-CW and GLC-TW revealed significantly higher specific capacitance values of 214 F/g and 182 F/g respectively, along with cycling stability of 98 % and 95 % during 5000 cycles of charge and discharge at 2 A/g current density. This approach can produce high-performance electrode materials for supercapacitors at a reasonable cost and with easy scalability.

Zinc cobalt sulfide with carbon (graphene oxide and CNT) based nanocomposite as positive electrode for asymmetric coin cell supercapacitors

Abstract The world dependence on portable electronic devices has increased the demand for high-performance energy storage devices. The use of transition metal sulfides as faradaic electrode materials for electrochemical energy storage is rapidly increasing due to their high energy density. Herein Zinc Cobalt Sulfide (ZCS) with graphene oxide (GO) and carbon nanotubes (CNT) were used to create an interconnected ZCS composite network using a solvothermal technique. The materials were characterized by utilizing XRD, FT-Raman, TGA, FESEM/EDX, XPS, and BET. The electrochemical performance of the materials was examined using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The prepared electrodes exhibited both pseudocapacitor behavior and double-layer capacitor behavior, indicating the hybrid nature. Furthermore, All the electrode ZCS, ZCS/GO, ZCS/CNT, and ZCS/GO/CNT electrodes demonstrated higher capacitance behavior, with values of 420, 551, 585 and 811 F g−1 at 1 A/g. Among these ZCS/GO/CNT electrode exhibits outstanding electrochemical properties, with a notable retention of 81.08% at 10 Ag−1 because Combining ZCS nanoparticles with interconnected GO and CNT provides excellent electronic conductivity and stability. The assembled ZCS/GO/CNT//graphene oxide asymmetric coin cell (ACC) supercapacitor showed a high energy density of 33.3 Wh kg–1 at a power density of 624 W kg–1. The 3D nanostructure of ZCS/GO/CNT/Graphene oxide has great potential for developing foldable energy storage devices.

Functional metal-organic frameworks derived electrode materials for electrochemical energy storage: a review.

Pristine metal-organic frameworks (MOFs) are built through self-assembly of electron rich organic linkers and electron deficient metal nodes via coordinate bond. Due to the unique properties of MOFs like highly tunable frameworks, huge specific surface areas, flexible chemical composition, flexible structures and a large volume of pores, they are being used to design the electrode materials for electrochemical energy storage devices. As per the literature, MOFs (including manganese, nickel, copper, and cobalt-based zeolitic imidazolate frameworks (ZIFs), University of Oslo (UiO) MOFs, Hong Kong University of Science and Technology (HKUST) MOFs and isoreticular MOFs (IRMOFs)) have attracted much attention in the field of supercapacitors (SCs)/batteries. According to their dimensionality such as 1D, 2D and 3D, pristine MOFs are mainly used as SC materials. Highly porous materials and their composites are capable for intercalation of metal ions (Na+/Li+). Moreover, the supramolecular features (π⋯π, C-H⋯π, hydrogen bond interactions) of redox stable MOFs provide better insight for electrochemical stability. So, this review provides an in-depth analysis of pure MOFs and MOF derived composites (MOF composites and MOF derived porous carbon) as electrode materials and also discusses their metal ion charge storage mechanism. Finally, we provide our perspectives on the current issues and future opportunities for supercapacitor materials.

Rapid and controllable microwave synthesis of nickel cobalt sulfide electrodes for high-performance asymmetric supercapacitors

The efficient and controllable synthesis method of high-performance energy storage electrode materials is crucial for advancing the development of energy storage technologies. Herein, by leveraging microwave heating technology in the sulfidation of nickel cobalt MOF, we effectively enhanced the efficiency of the synthesis process. Notably, sulfidation time emerged as a pivotal factor in tuning the crystalline phase structure and conductive properties of the material, leading to the successful development of NCS2 electrode material with a unique structure through optimized sulfidation conditions. Electrochemical performance tests of the NCS2 material revealed exceptional results; it exhibited a specific capacity of 1311 Fg[Formula: see text] at a current density of 1 Ag[Formula: see text] and retained 73.4% of its initial capacity when the current density increased to 10 Ag[Formula: see text], demonstrating outstanding rate performance. The composite NCS2//AC supercapacitor exhibits an energy density of 24.2 Whkg[Formula: see text] at power density of 800 Wkg[Formula: see text], even though after 1000 consecutive charge-discharge cycles, the capacity retention rate remained high at 77.1%, validating the exceptional stability and reliability of the NCS2 material during cycling. This work employs microwave sulfidation for the rapid and controlled synthesis of nickel cobalt sulfides, providing a green and efficient synthetic strategy for metal sulfide active materials.

Graphene wrapped porous polyaniline/manganese oxide nanocomposites with enhanced structural stability and conductivity for high‐performance symmetric supercapacitor

AbstractManganese oxides have emerged as promising electrode materials for supercapacitors. Despite extensive efforts to improve their conductivity and structural stability through various manganese oxide/conductor nanocomposites, achieving efficient and reliable energy storage electrode materials has remained challenging. In this study, we propose a meticulous “dual enhancement” strategy, where three‐dimensional (3D) nanostructured polyaniline/manganese oxide composites (PM) are synthesized via an in situ method and further integrated with graphene wrapping to form polyaniline/manganese oxide/graphene nanocomposites (PMG). Electrochemical characterization reveals that PMG exhibits a remarkable specific capacitance of up to 403 F g−1 (at 1 A g−1), with a favorable capacitance retention of 80.2% after 5000 cycles, along with a wide potential window. This enhancement is attributed to the synergistic effects of polyaniline, which provides a supportive framework and electron transport pathways, and graphene, which offers external protection and enhances conductivity pathways. Assembled symmetrical supercapacitors demonstrate outstanding energy density (32.7–23.3 Wh kg−1) and power density (720–4500 W kg−1) at a high operating voltage of 1.8 V, surpassing the performance of many reported high‐performance supercapacitors. This study provides valuable insights for advancing manganese oxide electrode materials and is expected to catalyze their widespread adoption in energy storage applications.Highlights “Dual enhancement” is implemented by PANI supporting and rGO wrapping. The conductivity and structural stability of composite electrode is greatly enhanced. Improved capacitance (403 F g−1, 1 A g−1) and cycling stability (80.2%) is achieved. The symmetrical supercapacitor has high voltage and energy density (32.7 Wh kg−1).

Amplifying energy storage and production efficiency: Utilizing BaS3: Ni2S3: Sb2S3 synthesized from dithiocarbamate precursors for enhanced and sustainable energy solutions

During this period of increasing energy use, the scientific community and energy stakeholders have been closely monitoring electrochemical energy storage. In an attempt to enhance the functionality of charge storage devices, diethyldithiocarbamate ligand is employed as a chelating agent during the production of the novel BaS3: Ni2S3: Sb2S3. The semiconductor BaS3: Ni2S3: Sb2S3, which was made in an environmentally friendly manner, showed good photoactivity due to its 2.97 eV energy band gap and light absorption. The resultant chalcogenide had an average crystallite size of 19.69 nm and displayed outstanding crystallinity with mixed crystallographic phases. Furthermore, infrared spectroscopy was used to investigate metallic sulfide connections, and the findings indicated that they varied between 500 and 875 cm−1. This chalcogenide featured varied sites for electrochemical reactions due to its morphology. The electrochemical performance of BaS3: Ni2S3: Sb2S3 was assessed using a conventional three-electrode setup. With a specific capacitance of up to 1019.4 F g−1 and a power density of 11931.26 W kg−1, BaS3: Ni2S3: Sb2S3 has proven to be an excellent electrode material for energy storage. This remarkable electrochemical performance was further reinforced by the comparable series resistance (Rs) of 0.57 Ω. During electrocatalysis, the electrode produced an OER overpotential with a Tafel slope of 348 mV and 119 mV dec−1. In contrast, the overpotential and Tafel slope in terms of the HER activity and were 211 mV and 100 mV/dec, respectively.

Ti3C2Tx-MXene based 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure for enhanced pseudocapacitive performance

Ti3C2Tx MXene family is a promising electrode material for electrochemical energy storage, but it suffers from insufficient pseudocapacitive charge storage because of self-aggregation and oxidation degradation. To resolve the issue, this paper proposes a two-step process for synthesizing oxidation-controlled MXene-derived 2D/3D heterostructures that beneficially utilize oxidation and simultaneously improve conductivity. The first step generates in-situ 3D floral Ti3C2– TiO2 nanoribbons under partial oxidation of MXene. As the second step, further controlled oxidation with Cu ions transforms the 3D floral Ti3C2–TiO2 nanoribbons into 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure. Leveraging the synergistic effects of MXene, TiO2, and CuTiO3, this 2D/3D heterostructure enhances the interlayered spacing, redox-active site concentration and alleviates low conductivity issue associated with TiO2 nanoribbons. At 2 mA/cm2, the proposed 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure achieved a significantly higher capacitance of 599.2 mF/cm2, compared to MXene with a capacitance of 249.16 mF/cm2 and 3D floral Ti3C2–TiO2 nanoribbons with 498.5 mF/cm2. For practical evaluation, an asymmetric supercapacitor (ASC) device (Ti3C2–TiO2–CuTiO3//AC) was fabricated, which exhibited an energy density of 31.1 Wh/kg, power density of 1041.7 W/kg and capacitance retention of 83.7 % after 5000 continuous charging/discharging cycles. It opens new avenues for utilizing controlled oxidation to enhance pseudocapacitive properties.

Modification Strategies and Prospects for Enhancing the Stability of Black Phosphorus.

Black phosphorus is a two-dimensional layer material with promising applications due to its many excellent physicochemical properties, including high carrier mobility, ambipolar field effect and unusual in-plane anisotropy. Currently, BP has been widely used in biomedical engineering, photocatalysis, semiconductor devices, and energy storage electrode materials. However, the unique structure of BP makes it highly chemically active, leading to its easy oxidation and degradation in air, which limits its practical applications. Recently, researchers have proposed a number of initiatives that can address the environmental instability of BP, and the application of these physical and chemical passivation techniques can effectively enhance the environmental stability of BP, including four modification methods: covalent functionalization, non-covalent functionalization, surface coordination, physical encapsulation and edge passivation. This review highlights the mechanisms of the above modification techniques in addressing the severe instability of BP in different application scenarios, as well as the advantages and disadvantages of each method. This review can provide guidance for more researchers in studying the marvellous properties of BP and accelerate the practical application of BP in different fields.

A Novelly Hierarchical LDHs−Based Cathode with Reduced Deprotonation Barrier Toward High−Performance Alkaline Energy Storage

AbstractLayered double hydroxides (LDHs) are promising electrode materials for alkaline electrochemical energy storage (EES). However, their low capacity, sluggish rate performance, and limited cycle life significantly hinder practical applications. This study unlocks the direct deprotonation reaction pathway for LDH materials through theoretical calculations. Guided by this insight, a novelly hierarchical composite (LDH−TPA) with various dimensions and components is fabricated by introducing terephthalic acid (TPA), serving as a superior cathode material for alkaline EES devices. Experimental results and theoretical investigations reveal the transformation process for metal–organic framework quantum dots (MOF−QDs) and the enhanced mechanism of reaction kinetics in the LDH−TPA electrode. Benefiting from the reduced deprotonation barrier, optimized electronic structure, and fast electrons/ions transport rates, the LDH−TPA1 electrode demonstrates a high specific capacity of 267 mAh g−1 at 1 A g−1 and retains 167 mAh g−1 even at 20 A g−1, along with excellent cycling stability. Furthermore, an alkaline nickel−zinc battery (AZB) with LDH−TPA1 cathode is assembled, achieving a lifespan exceeding 3400 cycles, and a high energy density of 341.3 Wh kg−1 at a power density of 1640.9 W kg−1. This study is expected to provide new insight into the modification of LDHs and the advancement of alkaline energy systems.

Synthesized and characterization of Ce2(MoO4)2(Mo2O7)/MoO3 nanocomposites with Schiff-base ligand assistance as possible electrode materials for electrochemical energy storage

Transition metal oxides, which can deliver a cooperative impact through electrochemical processes, are now being investigated extensively as potential electrode materials for next-generation storage devices. Ce2(MoO4)2(Mo2O7)/MoO3 composites were created using hydrothermal technique aided by Schiff-base ligands in the low temperature and short time. Synthesis of composites in the presence of different ligands led to design different morphologies such as particles, plates, flower-shaped and spheres. The produced sample functions as an active component of the electrochemical energy storing arrangement, which is included of a KOH electrolyte and a three-electrode cell. Morphology affects both the durability of the compounds in the designed working electrode and the kinetics of the electrochemical process. Although, capacitance of Ce2(MoO4)2(Mo2O7)/MoO3 composites was considered at different morphologies for determining optimal performance. Results show ideal sample prepared in the presence of H2acacmda with microsphere morphology and surface area of 12.83 m2g−1 which demonstrates maximum capacity of 246 mAhg−1.

Exploring the Electrochemical Superiority of V2O5/TiO2@Ti3C2-MXene Hybrid Nanostructures for Enhanced Lithium-Ion Battery Performance.

The use of vanadium(V)-based materials as electrode materials in electrochemical energy storage (EES) devices is promising due to their structural and chemical variety, abundance, and low cost. V-based materials with a layered structure and high multielectron transfer in the redox reaction have been actively explored for energy storage. Our current work presents the structural and electrochemical properties of a vanadium-based composite with TiO2@Ti3C2 MXene, referred to as VM. This composite is obtained through the in situ thermal decomposition of the VO2(OH)/Ti3C2mixture, which is achieved by solution mixing and drying. The material structure is confirmed using various characterization tools, which establish an orthorhombic V2O5 nanostructure compositing with nanocrystalline TiO2@Ti3C2. VM with 5 wt % MXene, referred to as VM5, can achieve 460 mAhg-1 at a current density of 0.1 Ag1- and 290 mAhg-1 at 1 Ag1-, with an average coulombic efficiency of 98.5%. The presence of the V2O5/TiO2 (nanocrystals) heterojunction attached with Ti3C2 sheets contributed to reduced charge transfer resistance. The cyclic stability shows a capacity retention of 62% over 500 cycles at 1 Ag1- (4C rate, where 1C equals 0.25 Ag1-) with a 0.22 capacity drop with each cycle. Dunn's approach to examining the charge storage mechanism demonstrates 72% contribution of the surface-dominant capacitive process and 28% of the diffusion-controlled intercalation process at 0.4 mVs-1, suggesting a potential high-performance pseudocapacitive hybrid electrode material for lithium-ion batteries.

XGBoost-based prediction of electrical properties for anode aluminium foil

Anode aluminum foil (AAF) shows advantages such as high electrical conductivity, high specific capacitance, and low cost, making it a high-quality electrode material for energy storage. However, the formation of AAF is a material process with multiple influencing factors interacted with each other, and it is difficult to analyze the influencing mechanism of each factor and predict the electrical properties. To solve the aforementioned problem, the process data of AAF is collected from a actual production line as the research subject firstly. The correlation coefficient between the process parameters and withstand voltage (WV) is used for feature selection of the data sets. XGBoost-based prediction model is established to predict the electrical properties of AAF, which is evaluated using R2 and root-mean-square error (RMSE). The results indicate that the process parameter X70 (Voltage of repair 3) shows the most significant effect on the WV. The magnitude of the WV shows a stepwise increase with the increase of X70. The result of prediction model is a R2 of 0.990 and a RMSE of 3.888. The XGBoost-based prediction model for the electrical properties (WV) of AAF shows excellent prediction characteristic, which contributes to the optimization of process parameters and the properties prediction.

Scalable synthesis of micro@meso porous carbon using crop-waste as cost-effective electrode materials for energy storage

Scalable synthesis of micro@meso porous carbon using crop-waste as cost-effective electrode materials for energy storage

FeSnO3/rGO nanocomposite electrode development for supercapacitor application

The manufacturing of electrode materials that are both highly efficient and cost-effective is crucial for energy storage systems. Because of their remarkable performance, nanocomposite materials are a good choice for creating energy storage systems. And the present study contains the fabrication of FeSnO3 and FeSnO3/rGO nanocomposite by hydrothermal approach. To assess electrochemical behavior of FeSnO3 and FeSnO3/rGO nanocomposite number of analytical tools such as galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry (CA) were employed. FeSnO3/rGO nanocomposite demonstrate specific capacitance (Csp) 1342.02 F/g and energy density (Ed) was 88.74 Wh/kg at a power density (Pd) of 345 W/kg at a current density of 1.0 A/g. The charge transfer resistance (Rct) of FeSnO3/rGO nanocomposite was found to be Rct = 0.43 Ω which was determined from Nyquist plot as well as showed cycling stability even after remains 5000th cycles. The addition of rGO increased the specific capacitance as well as surface area rise total number of active sites which allows electrolyte and electrode surface to make ideal connection for quick electrolyte ion diffusion. In accordance with the obtained findings, the FeSnO3/rGO nanocomposite is convincing capacitive electrode material for energy storage devices the future.

Microwave-assisted sol-gel synthesis of MFe2O4@SiO2 (M = Cu, Ni, Co) ceramic nanostructures using rice husk as a sustainable precursor for electrochemical energy storage

In this study, we report the synthesis of MFe2O4@SiO2 (M = Cu, Ni, Co) nanostructures by microwave-assisted sol-gel synthesis utilizing rice husk as a cost-effective silica precursor and polyethylene glycol (PEG) as a soft template. Structural and electrochemical properties were characterized using XRD, FTIR, FESEM, EDS, HRTEM, BET, and electrochemical techniques. The result revealed the formation of well-defined MFe2O4 spherical nanoparticles decorated mesoporous silica spheres. Electrochemical studies indicate that the CoFe2O4@SiO2 electrode performs better than the CuFe2O4@SiO2 and NiFe2O4@SiO2 electrodes in faradaic redox processes and supercapacitor performance, having a specific capacitance of 1263 F/g at 1 A. Asymmetric supercapacitor (ASC) with CoFe2O4@SiO2 as positive electrode exhibits high specific capacitance of 135.66 F/g at 1 A/g with good cycle stability retention (70.83 % at 10 A/g), high energy density (50.4 Wh/kg) and power density (891.522 W/kg). CoFe2O4@SiO2 performs better than CuFe2O4@SiO2 and NiFe2O4@SiO2 because cobalt ferrite (CoFe2O4) has higher electrical conductivity, superior redox activity, and better electrochemical stability. This study offers cost-effective potential electrode materials for electrochemical energy storage, combining environmental sustainability with superior electrochemical performance.

Bimolecular Salt Strategy Enhances Heteroatom Doping and Porosity Optimization of Porous Carbon for Supercapacitors.

The incompatibility between electrolyte ions and electrode pore sizes, coupled with the extensive use of activators and dopants, significantly restricts the fabrication of porous carbon materials. Consequently, developing environmentally sustainable and efficient methodologies that exploit the intrinsic properties and pretreatment of materials to facilitate self-activation and self-doping becomes crucial. In this study, potassium histidine and magnesium histidine molecular salts were synthesized as precursors, enabling specific ion activation and bimetallic template-directed tunable porosity through a one-step carbonization process. Notably, the ratio of bimolecular salts significantly influenced the porous structure of carbon, the properties of heteroatoms, and the electrochemical performance. By optimizing the ratio, the porous carbon materials exhibited high accessibility to electrolyte ions and effective ion/electron transport channels. Consequently, the optimal sample (NOSPC-2) achieved a high specific capacitance of 318 F g-1 at 0.1 A g-1 and a good capacitance retention rate of 98.8% after 50,000 cycles at 5 A g-1. In addition, NOSPC-2 also boasted high energy density and power density, reaching 22 Wh kg-1 and 25 kW kg-1, respectively. This research represents a significant stride in advancing preparation technologies for small molecule derived porous carbon materials, providing valuable insights for the rational design of carbon electrode materials for capacitive energy storage.

Bipolar Supercapacitive Performance of N-Containing Carbon Materials Derived from Covalent Triazine-Based Framework.

The search for new electrode materials for bipolar-supercapacitor performance is the intention of numerous research in the area of functional framework materials. Among various electrode materials, covalent triazine-based frameworks (CTFs) are in the spotlight drawing much attention as potential electrode material for energy storage. Herein, we present the synthesis of nitrogen-functionalized CTFs marked as CTF-Py-600 and CTF-Py-700 with high nitrogen content (18% and 14%, respectively) for supercapacitor application by applying 2,6-dicyanopyridine monomer via the polymerization reaction under ionothermal condition. The BET surface area of these materials are in the range of 940-1999 m2g-1. CTF-Py-700 demonstrates outstanding electrochemical performance in both potential windows. At the negative potential window, it exhibits a higher specific capacitance of 435 F g-1 (at 1 A g-1) compared to the positive potential window, where it shows a specific capacitance of 306 F g-1 (at 1 A g-1) owing to the synergistic existence of its large surface area (1999 m2g-1) and high nitrogen content (14%) with inherent microporosity. Remarkable cycling stability without noticeable degradation of specific capacitance after 15000 cycles was recorded for CTF-Py-700. This suggests that the nitrogen-functionalized CTFs are going to be a highly demanded electrode material for electrochemical energy storage applications.

Oxalate-derived porous C-doped NiO with amorphous-crystalline heterophase for supercapacitors

Constructing amorphous/crystalline heterophase structure with high porosity is a promising strategy to effectively tailor the physicochemical properties of electrode materials and further improve the electrochemical performance of supercapacitors. Here, the porous C-doped NiO (C-NiO) with amorphous/crystalline heterophase grown on NF was prepared using NF as Ni source via a self-sacrificial template method. Calcining the self-sacrificial NiC2O4 template at a suitable temperature (400 °C) was beneficial to the formation of porous heterophase structure with abundant cavities and cracks, resulting in high electrical conductivity and rich ion/electron-transport channels. The density functional theory (DFT) calculations further verified that in-situ C-doping could modulate the electronic structure and enhance the OH− adsorption capability. The unique porous amorphous/crystalline heterophase structure greatly accelerated electrons/ions transfer and Faradaic reaction kinetic, which effectively improved the charge storage. The C-NiO calcined at 400 °C (C-NiO(400)) displayed a markedly enhanced specific charge, outstanding rate property and excellent cycling stability. Furthermore, the hybrid supercapacitor assembled by C-NiO(400) and active carbon achieved a high energy density of 49.0 Wh kg−1 at 800 W kg−1 and excellent cycle stability (90.9 % retention at 5 A/g after 10 000 cycles). This work provided a new strategy for designing amorphous/crystalline heterophase electrode materials in high-performance energy storage.

In situ decoration of 0D-nickel boride on 2D-vanadium MXene composites: An advanced electrode material for high energy density supercapacitors

Vanadium carbide-MXene (V2CTx) is considered a rising star among 2D materials and is an ideal electrode material for energy storage due to its unique features. However, oxidation and layer restacking can impair specific capacity (Cs) and cycling performance. Considering this challenge, we have developed a composite material consisting of amorphous nickel boride (NixB NPs) and V2CTx. To prevent oxidation and restacking of the layers and to improve the performance of the supercapacitor, NixB was decorated between the gaps and the surface. The V2CTx and its composites were prepared by simple etching and direct liquid-phase methods. Under the optimized conditions, the NixB/V2CTx modified nickel foam exhibited an improved Cs value of 705.9 C g−1 and a rate capability of 53.8 % at a current density of 10 A g−1; the excellent cycling stability was 120.5 % after 10,000 cycles at 10 A g−1 in 3 M KOH. The improved Cs values, shortened ion diffusion paths, swift electron transfer, and excellent cycling stability of the composites are due to the V2CTx layers surface entrapped/gaps filled by the NixB NPs. For practical application, an asymmetric device with NixB/V2CTx and reduced graphene oxide (rGO) as positive and negative electrodes was fabricated. The NixB/V2CTx//rGO device achieved a maximum energy density of 50.22 Wh kg−1 at 800 W kg−1 and 26 Wh kg−1 at 16000 W kg−1. The capacity retention was 89.98 % and the Coulombic efficiency was 99.9 % after 20,000 continuous cycles at 8 A g−1. These results emphasized that the developed 0D/2D NixB/V2CTx electrode materials with novel composite architecture are suitable for advanced energy storage applications.