Battery Cycle Life Research Articles

A Feed-Forward Back-Propagation Neural Network Approach for Integration of Electric Vehicles into Vehicle-to-Grid (V2G) to Predict State of Charge for Lithium-Ion Batteries

The accurate prediction and efficient management of the State of Charge (SoC) of electric vehicle (EV) batteries are critical challenges in the integration of vehicle-to-grid (V2G) systems within multi-energy microgrid (MMO) models. Inaccurate SoC estimation can lead to inefficiencies, increased costs, and potential disruptions in power generation. This paper addresses the problem of optimizing SoC estimation to enhance the reliability and efficiency of V2G scheduling and MMO coordination. In this work, we develop a Feed-Forward Back-Propagation Network (FFBPN) using MATLAB 2024 software, employing the Levenberg–Marquardt algorithm and varying the number of hidden neurons to achieve better performance; performance was measured by the maximum coefficient of determination (R2) and the minimum mean squared error (MSE). Utilizing the NASA Prognostics Center of Excellence (PCoE) dataset, we validate the model’s capability to accurately predict the life cycle of EV batteries. Our proposed FFBPN model demonstrates superior performance compared to existing methods from the literature, offering significant implications for future V2G system developments. The comparison between training, validation, and testing phases underscores the model’s validity and precisely identifies the characteristic curves of FFBPN, showcasing its potential to enhance profitability, efficiency, production, energy savings, and minimize environmental impact.

High-temperature (800 °C) performance of spodumene slag-based ternary sulphate composite phase change materials with improved mechanical property

The large deployment of electric vehicles leads to decarbonised road transport. However, the mining and smelting of lithium resources will continue to increase, which generates lithium slag and urgently needs to be recycled. The integration of spodumene slag with ternary sulphate presents a green and promising approach to achieve resource recycling and high-performance composite phase change material (CPCM). Herein, toughened and strengthened CPCMs are prepared by the hybrid sintering method with mechanical properties better than reinterned glass, even after high-temperature thermal cycling. After the cold compression and hot sintering process, the production of colloidal sodium silicate bonds the ternary sulphate with the spodumene slag skeleton, which greatly enhances the strength of the CPCM for efficient and durable thermal energy storage (TES). The Hydroxyl polar group of sodium silicate interacts with the skeleton and leads to a record-breaking compressive strength of 155.23 MPa, and the CPCM can support its stacking of 23.6 m and 15 kg loading test at 700 °C. A negligible mass loss of 0.26 wt% was observed after 50 thermal cycles at 800 °C. Moreover, the CPCMs exhibit a high TES density of up to 873.0 J/g in the temperature range of 100–800 °C. High charging and round-trip efficiency in the heat recovery process from spodumene roasting is also achieved, as it is 5 % and 19 % higher than the common magnesium bricks, respectively. The CPCM achieves high thermal efficiency TES, and it is the effective resource recycling of lithium slag with simple material preparation, which, from two angles at once, attacks the carbon emission from the life cycle of the lithium-ion battery.

Zn2+ flux regulator to modulate the interface chemistry toward highly reversible Zn anode

The persistent challenges of diminished coulombic efficiency (CE) and the formation of Zn dendrites at the Zn anode interface substantially hinder the cycle life of aqueous Zn-ion batteries (AZIBs), thereby impeding their widespread deployment. To address these issues, multifunctional 2-amino-5-guanidino-pentanoic acid (AGPA) additive is introduced into the electrolyte, as a novel Zn2+ flux regulator (ZFR) to improve the reversibility and durability of Zn anodes. The distinctive zincophilicity of amino groups empowers such ZFR with a higher adsorption energy, enabling the construction of a multifunctional molecular adsorption layer on Zn electrode surface. Simultaneously, leveraging the exceptional nucleophilic characteristics of polar carboxyl groups, AGPA molecules tend to form chelating bonds with Zn2+ for manipulating the interface chemistry and solvation chemistry. The functional groups in ZFR work in synergy to attract zinc ions for homogenizing Zn2+ flux and suppress the interfacial side reactions, resulting in uniform dendrite-free Zn deposition. Consequently, the Zn//Zn symmetrical cell achieves an extended cycle life of 5500 h. Moreover, the ZFR enables stable operation of the full batteries with an ultra-long cycling lifespan of 6000 cycles at 5 A/g, showcasing the effectiveness of ZFR in advancing the commercialization of AZIBs.

Multiscale approaches for optimizing the impact of strain on Na-ion battery cycle life

Abstract The high costs and geopolitical challenges inherent to the lithium-ion (Li-ion) battery supply chain have driven a rising interest in the development of sodium-ion (Na-ion) batteries as a potential alternative. Unfortunately, the larger ionic radius of Na limits the reversibility of cycling because of the extensive atomic rearrangements that accompany Na-ion insertion, which in turn limit diffusion and charging speed, and lead to rapid degradation of the electrodes. The Center for Strain Optimization for Renewable Energy (STORE) was established to address these challenges and develop new electrode materials for Na-ion cells. This article discusses the current state-of-the-art materials used in Na-ion cells and several directions that STORE believes are critical to understand and control the structural and volumetric changes during the reversible (de)insertion of large cations. Graphical abstract Highlights Understanding the fundamental way materials respond to localized strains at the atomic length-scale is a critical first step in the development of highly reversible, long cycle life, Na-ion insertion hosts. This perspective explores a variety of methods that can be employed to mitigate the detrimental effects of large strain. The insights gained from these investigations should help lay the foundation for the creation of more economical and sustainable batteries that could have immediate impact on global energy infrastructure. Discussion Although there is near universal agreement that electrochemical energy storage must be an integral part of a green-energy future, there is less agreement about how to reduce the cost of energy storage. Replacing high-cost lithium-ion cells with lower-cost sodium-ion batteries is one option frequently considered in future energy models, but the details of what can be achieve with optimized sodium cell performance remains unclear. Here we posit that developing methods to mitigating strain on the electrode particle length scale is a key factor for achieving long-cycle-life sodium-ion batteries. Mitigating strain on the atomic scale suppress electrode-level volume change. Allowing for fast cycling in materials without the problems of electrode cracking or delamination. We further posit that understanding volume change in sodium-ion electrodes at a fundamental level will lead to the designing new sodium-ion electrode materials that will allow for efficient, stable, lower-cost energy storage.

Analysis of the effect of buffer pads on the cycle life of lithium-ion pouch batteries

Analysis of the effect of buffer pads on the cycle life of lithium-ion pouch batteries

Fast estimation method for lithium battery state of health based on incremental capacity curve peak characteristics

State of Health (SOH) estimation for lithium-ion batteries is a complex task, often plagued by issues such as slow estimation speed and high practical application difficulty in existing methods. In this paper, capacity is established as the criterion for defining State of Health. We conducted an analysis of Incremental Capacity (IC) curves, examining the characteristic features of the incremental capacity curves throughout the entire lifecycle of lithium-ion batteries at different temperatures and charge-discharge rates. The investigation revealed that the peaks in the incremental capacity curves correspond to nearly constant State of Charge (SOC) values. Building upon this discovery, a rapid SOH estimation method based on IC curves is proposed. The method was validated using data from the complete lifecycle of 18,650 cells, yielding a maximum SOH estimation error of 3%. Furthermore, the proposed method was applied to 240 cells in an energy storage battery pack at a specific station, resulting in a maximum SOH estimation error of 3.9%. This demonstrates the feasibility of the method under practical conditions, highlighting its high precision in SOH estimation. The proposed approach holds significant promise for real-time and rapid SOH estimation and detection, offering valuable insights for battery health monitoring.

Understanding and Regulating the Mechanical Stability of Solid Electrolyte Interphase in Batteries

AbstractThe unstable interface between reactive anodes and electrolytes in batteries has been identified as a critical factor in limiting the long‐cycle stability of batteries. An effective solution is to build a solid electrolyte interphase (SEI) that acts as a passivation layer to mitigate the side reactions between reactive anodes and electrolytes. The mechanical stability of SEI is important because SEI with poor mechanical stability cannot survive the volume and topography fluctuation of the anode upon cycling. The stress built‐up would cause mechanical failure of SEI, resulting in exposure of the fresh anode surface to the electrolyte, consuming the limited active materials and electrolytes, and inducing rapid battery decay. Therefore, understanding and regulating the mechanical stability of SEI is imperative for improving battery cycle life. In this review, the mechanical properties of SEI are discussed. Then, advanced characterization tools to measure the mechanical properties of SEI are introduced. Additionally, recent progress on improving the mechanical stability of SEI is presented in terms of in situ and ex situ modifications of SEI. Finally, an insightful outlook is provided to further understand and regulate the mechanical stability of SEI for improving battery performance.

A novel NASICON-typed Na3V1.96Cr0.03Mn0.01(PO4)2F3 cathode for high-performance Na-ion batteries

Na3V2(PO4)2F3 (NVPF) with a NASICON structure has attracted widespread attention as a cathode material for sodium-ion batteries due to its stable 3d open framework, high operating voltage, and high theoretical energy density. However, this material faces limitations in practical applications due to its inherently low intrinsic electronic conductivity and the high cost of vanadium. In this study, we substituted vanadium with low-cost elements and synthesized a series of NVPF cathode materials with varying levels of Cr/Mn doping using a simple sol-gel method. The optimal NVPF-Cr/Mn1 cathode exhibits discharge specific capacities of 119.7 mAh g−1 at 1C and 109.8 mAh g−1 at 10C. Additionally, the discharge specific capacity of NVPF-Cr/Mn1 is 106.9 mAh g−1, with a capacity retention rate of 80 % after 400 cycles. These performance improvements are attributed to the synergistic effect of co-doping with chromium (Cr) and manganese (Mn): they expand the channels for sodium ion transport within the lattice, reduce the material's impedance and polarization, enhance the kinetics of sodium ion diffusion reactions, effectively prevent lattice distortion, and significantly improve long-term cycling performance. By strategically designing NASICON-type cathodes and employing multi-metal ion substitutions to regulate composition, we not only enhance the battery's cycle life but also contribute to reducing the cost of electrode materials. This approach opens up new possibilities for practical applications in the field of energy storage.

Comprehensive study of rapid capacity fade in prismatic Li-ion cells with flexible packaging

Prismatic lithium-ion batteries (LIBs) are considered promising electric energy sources in electromobility applications due to their efficient space utilization. However, their sensitivity to external and internal influences and reduced durability lead to inflation risk and potential explosions throughout their lifecycle. These critical processes are strongly influenced by the inner construction of the cell, especially concerning the coating and mechanical fixation. This study subjects a commercially available prismatic LIB cell to comprehensive, correlative analysis employing various imaging techniques. The inner structure of the entire cell is visualized non-destructively by X-ray computed tomography (CT), enabling the identification of critical design flaws prior to electrochemical cycling. Electrochemical cycling simulates the battery lifecycle, and the cell is subsequently disassembled in the fully charged state. The usage of the inert-gas transfer system allowed the preparation of Broad Ion Beam (BIB) electrodes cross-sections in a fully native state and for the first time to observe the tearing of graphite particles due to over-lithiation. Established region labeling system allowed to use CT and scanning electron microscopy (SEM) correlatively to identify critical regions. After 100 cycles, a 40% capacity loss was observed and event diagram describing deagradation mechanisms, related both to the cell design and to the processes occurring at high load, was created.

Systematic Review of Battery Life Cycle Management: A Framework for European Regulation Compliance

Batteries are fundamental to the sustainable energy transition, playing a key role in both powering devices and storing renewable energy. They are also essential in the shift towards greener automotive solutions. However, battery life cycles face significant environmental challenges, including the harmful impacts of extraction and refining processes and inefficiencies in recycling. Both researchers and policymakers are striving to improve battery technologies through a combination of bottom–up innovations and top–down regulations. This study aims to bridge the gap between scientific advancements and policy frameworks by conducting a Systematic Literature Review of 177 papers. The review identifies innovative solutions to mitigate challenges across the battery life cycle, from production to disposal. A key outcome of this work is the creation of the life cycle management framework, designed to align scientific developments with regulatory strategies, providing an integrated approach to address life cycle challenges. This framework offers a comprehensive tool to guide stakeholders in fostering a sustainable battery ecosystem, contributing to the objectives set by the European Commission’s battery regulation.

The Key Role of N/S Codoped Carbon Dots in Efficient Capture and Conversion of Lithium Polysulfides

AbstractThe dissolution and shuttle of lithium polysulfides (LiPSs) should be primarily responsible for rapid capacity decay in lithium‐sulfur batteries (LSBs), which severely limits sulfur utilization. Introduction of cathode additives that can immobilize and rapidly convert LiPSs has been identified as effective in alleviating the shuttle effect. In this study, N/S codoped carbon dots (NSCDs) have been synthesized via a typical hydrothermal method, whose surfaces are rich in polar functional groups (─COOH, ─OH, ─SO3, and ─NH2) to capture LiPSs and effectively modulate the deposition behavior of Li2S. NSCDs as an additive of cathode significantly improve the battery discharge capacity and cycle life that it could deliver a reversible specific capacity of 1207.2 mAh g−1 at a current density of 0.2 C and stably operate for over 400 cycles at 1 and 2 C current densities. This work provides valuable insights into the application of 0D carbon nanomaterials in the field of LSBs.

Multi-scale analysis of voltage curves for accurate and adaptable lifecycle prediction of lithium-ion batteries

Health status prediction of lithium-ion batteries is critical for the stable operation of electrical equipment. The data-driven approach can fit the degradation laws based on the historical cyclic data and identify potential problems in time. However, existing prediction methods mainly focus on acquiring various cyclic degradation features, and excessive battery-related data types increase the complexity and indeterminacy, posing a challenge for efficient and accurate prediction during practical application scenarios. Herein, this study only uses cyclic voltages and proposes a novel multi-scale cyclic voltage data preprocessing technique, involving the selection of highly correlated feature parameters with battery life in both the time and frequency domains, and constructing graphical samples with dynamic node connectivity properties. The proposed multi-scale graph convolutional network model adeptly captures and amalgamates the evolving features among graphical samples with efficacy. The one-step prediction experiments demonstrate the capability to predict subsequent capacity degradation solely based on the voltages of any consecutive 20 cycles, with a root mean square error of 0.173 %, exhibiting adaptable capability across different battery datasets. Compared to existing methods that transform data into images for health status prediction, this study highlights the significance of a multi-scale approach to voltage analysis in cyclic data, leveraging advanced feature engineering and modeling techniques, not only to enhance the accuracy and adaptability of battery lifecycle predictions but also to offer a robust framework for overcoming prevailing challenges in monitoring accuracy and cost-effectiveness.

Difluorobenzene as an Antisolvent for Fluorinated Electrolyte to Achieve Unparalleled Cycle Life of Lithium Metal Battery.

Electrolytes play a crucial role in enhancing the cycling stability and overall lifespan of lithium metal batteries (LMBs). However, conventional electrolytes achieve ununiform and low ionic conductivity solid electrolyte interphase (SEI), leading to uncontrolled lithium dendrite growth and dead lithium formation, rendering them inadequate for meeting the performance of high energy density LMBs. Herein, a 1,2-difluorobenzene (1,2-dFBn) is introduced as antisolvent in fluorinated electrolyte which is composed of fluoroethylene carbonate (FEC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The low energy level of the lowest unoccupied molecular orbital (LUMO) and the high fluorine-donating ability of 1,2-dFBn jointly modify the solvation structure and electrode/electrolyte interphase chemistry. As a result, this simple electrolyte formulation enables the Li||Li symmetric cells exhibit remarkable stability, enduring 700 h of continuous cycling under 2 mA cm-2 and Li||Cu cell achieve an impressive average Coulombic efficiency (CE) of 99.76%. Moreover, the full cell assembled with electrochemically deposited lithium capacity of 5 mAh cm-2 and LiFePO4 (LFP) as cathode achieves exceptional performance, maintaining a discharge specific capacity of 134.9 mAh g-1 while retaining 95.1% capacity at 2C after 1000 cycles. This study offers a plausible ratio design for fluorinated electrolyte, which achieving high CE and long-life LMBs.

Review and prospect on Metal-organic framework-based Separators for Lithium–Sulfur Battery

With the continuous advancement of technology, wearable smart devices and electric vehicles (EVs) have become an integral part of our daily lives. The increasing demand for energy from these devices and vehicles has driven the pursuit of high-performance rechargeable battery technology. In particular, the widespread adoption of electric vehicles has set higher standards for the energy density and cycle life of batteries. However, the energy density of the widely used lithium-ion batteries is currently limited by the theoretical capacity of commercial cathode materials, and there are certain challenges in terms of safety and cost-effectiveness. Therefore, the development of a new generation of rechargeable batteries with higher energy density, better safety, and more economical cost is particularly urgent. Lithium-sulfur batteries, due to their high energy density, high economic benefits, and high environmental friendliness, are considered to be one of the most promising successors to the widely used lithium-ion batteries. However, in practical applications, the electrochemical performance of lithium-sulfur batteries still needs to be improved. In particular, the poor conductivity of sulfur/lithium and the shuttle effect of polysulfides make the cycle life of the battery less than ideal, and lithium-sulfur batteries (LSB) are still far from achieving large-scale commercialization. The separator used in lithium-sulfur batteries plays a crucial role in its cycle performance and safety. The current commercial separator lacks the ability to effectively regulate the shuttle of polysulfides and is prone to thermal runaway at high temperatures. Therefore, to improve these issues, various functional materials have been used to modify the separator. Among them, as a new type of porous coordination polymer, metal organic frameworks (MOFs) have become a promising material for modifying separators due to their large specific surface area and highly ordered tunable nano-holes.At the same time, their rich inorganic nodes and designable organic ligands allow for the customization of pore chemistry at the molecular level, which can interact with the electroactive components in lithium-sulfur batteries in a tunable manner. This article reviews the reaction mechanism of lithium-sulfur batteries and the structural advantages of MOFs in terms of pore chemistry and morphology and briefly introduces the research progress of MOF-based interfacial layers for the functionalization of LSB separators in recent years. It elaborates on the mechanisms by which various modified separators improve electrochemical performance and provides a prospect for the development prospects of the field.

Nanotechnology in Lithium-Sulfur Batteries: Addressing the Challenges in Battery Cycle Life and Safety

Lithium-sulfur (Li-S) batteries, with their high energy density and affordable material prices, are a viable alternative to ordinary lithium-ion batteries, especially for electric cars. Their actual application is limited by challenges such as substantial volume expansion, low electrical conductivity, and the polysulfide shuttle effect, despite their advantages. This research investigates how incorporating nanomaterials into Li-S battery cathodes, anodes, and electrolytes might improve battery performance and analyzes the potential of nanotechnology to address these problems. The application of metal oxides, graphene oxide, and carbon nanofibers to improve the stability and conductivity of sulfur cathodes is covered. Additionally, it examines anode protection strategies using nanocoating and protective layers to inhibit dendrite growth and improve safety. The incorporation of nanoparticles in electrolytes to improve ionic conductivity and reduce side reactions is also analyzed. Despite the progress, challenges such as the polysulfide shuttle effect and volume changes remain. The paper concludes with recommendations for future research to develop commercially viable Li-S batteries with higher capacity, longer lifespan, and improved safety.

Porous V2CTx MXene as a High Stability Zinc Anode Protective Coating.

Aqueous Zn batteries exhibit significant research potential owing to their environmental friendliness and high energy density. Nevertheless, the formation of dendrites on the zinc anode and the sluggish diffusion kinetics of zinc ions adversely affect the cycle life of zinc ion batteries. In this study, we employ porous V2CTx (MVMX) as a protective layer for the zinc anode. The uniform porous structure of MVMX promotes active site exposure and facilitates the transport of zinc ions. Remarkably, the Zn@Ti half-cell demonstrated an average CE of 99.7% in 1500 cycles. Furthermore, the Zn-Zn symmetric battery exhibited stable cycling for 1600 h at current densities of 5 mA cm-2 and 1 mAh cm-2. Additionally, the MVMX@Zn||V2O5 full cell exhibited a capacity of 198 mAh g-1 and retained a capacity of 124.75 mAh g-1 after 5000 cycles at 1 A g-1, demonstrating the potential of employing alternative MXenes for fabricating stable zinc anodes.

Progress of silicon and graphene composites in lithium-ion battery anodes

As society progresses, the need for high-power, long-life energy supply devices gradually increases. Lithium-ion batteries (LIBs) with large energy reserves and high power have recently become the preferred choice. The anode of LIBs plays a crucial role in battery performance, safety, and cycle life. Typically, graphite materials are used for LIBs anodes. Still, they have drawbacks such as low first-time Coulombic efficiency, capacity degradation, safety issues, short cycle life, insufficient gram capacity, and purity and side reactions, which limit the application of LIBs. Therefore, new harmful electrode materials are in demand. Graphene and silicon are both environmentally friendly and sustainable materials. They both have the advantages of high theoretical capacity and high energy density, which are critical materials for developing LIBs. Combining the two can exert a synergistic effect and jointly improve the cycle stability of the battery. In this paper, we review the preparation methods of graphene and silicon composites in recent years, including mechanical ball milling and hydrothermal and thermal reduction methods. In addition, graphene and silicon composites have been explored for LIBs applications.

Sulfide/Polymer Composite Solid‐State Electrolytes for All‐Solid‐State Lithium Batteries

AbstractThis review introduces solid electrolytes based on sulfide/polymer composites which are used in all‐solid‐state lithium batteries, describing the use of polymers as plasticizer, the lithium‐ion conductive channel, the preparation methods of solid‐state electrolytes (SSEs), including dry methods and wet methods with their advantages and disadvantages. In addition, the physicochemical stability of sulfide/polymer composite based solid‐state electrolytes is analyzed. The sulfide/polymer composite based solid‐state electrolyte can be utilized in lithium metal or lithium sulfur batteries. However, there are still many problems left to be solved in practical applications of these solid‐state electrolytes. In this review, several solutions are explored. Firstly, the ultra‐long life cycle of batteries can be achieved by thinning the composite electrolyte. Secondly, when sulfur is applied as the positive electrode, the thinning electrolyte can reduce polarization and other problems. Finally, an integrated battery is employed to reduce the interface impedance. By addressing these aspects, the review aims to provide valuable insights into the future development of high‐performance solid‐state electrolytes in lithium battery technology.

Life Cycle of LiFePO4 Batteries: Production, Recycling, and Market Trends.

Significant attention has focused on olivine-structured LiFePO4 (LFP) as a promising cathode active material (CAM) for lithium-ion batteries. This iron-based compound offers advantages over commonly used Co and Ni due to its lower toxicity abundance, and cost-effectiveness. Despite its current commercial use in energy storage technology, there remains a need for cost-effective production methods to create electrochemically active LiFePO4. Consequently, there is ongoing interest in developing innovative approaches for LiFePO4 production. While LFP batteries exhibit significant thermal stability, cycling performance, and environmental benefits, their growing adoption has increased battery disposal rates. Improper disposal practices for waste LFP batteries result in environmental degradation and the depletion of valuable resources This review comprehensively examines diverse synthesis approaches for generating LFP powders, encompassing conventional methodologies alongside novel procedures. Furthermore, it conducts an in-depth assessment of the methodologies employed in recycling waste LFP batteries. Moreover, it emphasizes the importance of LFP cathode recycling and investigates pretreatment techniques to enhance understanding. Additionally, it provides valuable insights into the recycling process of used LFP batteries, aiming to raise awareness regarding the market for retired LFP batteries and advocate for the enduring sustainability of lithium-ion batteries.

Bifunctional electrolyte additive enabling long cycle life of vanadium-based cathode aqueous zinc ion batteries

Aqueous zinc ion batteries have received extensive attention due to their many advantages, but they still face problems such as dendrite growth and interface reaction of Zn anode and collapse of vanadium-based cathode structure. Here, a bifunctional electrolyte additive Methionine (MET) is proposed, which exhibits a unique role in inducing uniform deposition of zinc anode and inhibiting the failure of vanadium-based cathode materials. MET affects the solvated structure of the electrolyte to inhibit water activity and reduce HER and other related parasitic reactions. At the same time, it regulates the flux of Zn2+, improves the deposition kinetics of Zn2+ on the zinc anode side, and induces the preferential growth of the Zn (1 0 1) crystal plane to promote ordered Zn deposition. In particular, MET can in-situ generate a CEI containing such as ZnF2 on the surface of the vanadium-based cathode to inhibit the failure of the vanadium-based cathode, while adjusting the surface electronic state and Zn2+ diffusion behavior, and reducing the structural damage of the vanadium-based cathode caused by the Zn2+ intercalation process by inducing a strengthened surface pseudocapacitive reaction. Compared with the bare electrolyte, the capacity retention rate of the K2V8O21||Zn full-cell with OTF-M50 electrolyte increased from 10.2 % to 99.8 % after 800 cycles at a low current density of 1 A/g. Therefore, MET exhibits considerable application prospects as a bifunctional additive that can improve the stability of vanadium-based cathode and promote the stable deposition of zinc anode.