To investigation the effect of the microstructure and electrochemical behavior of the β-MnO₂ samples under high-energy ball milling. The crystal structure， particle morphology， size， and atomic arrangement of the sample are measured and analyzed by XRD， SEM， laser particle size analyzer， and TEM. The electrochemical performance， electrochemical impedance spectrum， and CV curve of the sample cell are measured by battery tester and electrochemical workstation. The results show that compared with the sample before ball milling， the phase structure space group of the sample after ball milling changes， the grain size and particle size are reduced， and the coexistence of crystalline and amorphous microstructure is formed. With the increase of ball milling time， the specimen particle morphology changes to fine dispersion → particle agglomeration and dispersion → particle agglomeration and platelet， while the lattice distortion is gradually serious. The number of cycles to reach the maximum discharge capacity of the specimen cell after ball milling is reduced， the discharge efficiency of all specimens is good. However， the maximum discharge capacity is related to the grain size， particle morphology， and lattice distortion caused by the ball milling time. In different ball milling time， the maximum discharge capacity of the as-milled sample cell at 4.0 h is relatively high. After 100 charge and discharge cycles， the capacity maintenance rate of the as-milled sample cell at 5.5 h is relatively good. According to the kinetic study， it is found that the charge transfer impedance and Warburg diffusion impedance of the 4.0 h as-milled specimen cell are relatively small and the peak area of cyclic voltammetry is relatively large compared with other cells， which further indicates that the specimen cell has a relatively high electrochemical capacity and a relatively small charge/discharge potential difference. Therefore， within the scope of this study， starting from capacity and capacity retention rate， the suitable ball milling time for β-MnO₂ samples is 4.0 h.

Electrochemical mechanical polishing （ECMP） technology is a new technology that can rapidly improve the efficiency of flattening silicon carbide （SiC）. Based on the complexity of formulating the polishing solution and the inability to combine efficient material removal and high surface quality at the same time， this paper develops a simple and environmentally friendly composition based on graphene oxide （GO） as a solid lubricant and a diamond suspension. A new SiC-ECMP polishing solution is developed. The new polishing solution is used to polish SiC with a smooth surface roughness of R _a 0.324 nm while maintaining a material removal rate of 2.38 μm/h. Macroscopic sedimentation experiments， zeta potential and particle size analysis experiments， and TEM analysis are performed to analyse the improvement of the stability of the polishing solution by GO， and the lubrication mechanism is revealed by contact angle， and friction and wear experiments. The results show that the addition of GO to the polishing solution inhibits the precipitation of abrasive， the particle size of the polishing solution becomes smaller and more uniformly distributed， and the stability of the slurry is improved； it reduces the contact angle between the polishing solution and the SiC surface and lowers the surface friction， which achieves the effect of wear reduction and lubrication.

As new energy vehicles proliferate and energy storage systems scale up， lithium-ion batteries confront market risks stemming from resource scarcity and price volatility. In this context， sodium-ion batteries have emerged as a promising alternative， leveraging their abundant resources to potentially complement lithium-ion batteries in large-scale electrochemical energy storage and low-speed electric vehicles. Despite the rapid surge in sodium-ion battery research and the onset of commercialization initiatives globally， several market and technological prerequisites persist， posing challenges compared to the well-established lithium-ion battery system. This article provides a concise overview of sodium-ion batteries from a commercialization perspective， tracing their development history and current industry standing. It delves into the core positive and negative electrode materials， costs， and application prospects within the existing sodium storage electrode material systems. Additionally， the article presents a forward-looking analysis of future opportunities and challenges， aiming to guide further advancements in the sodium-ion battery industry.

Lithium-ion batteries quickly occupy the absolute leading position in the secondary battery market because of their high energy density and long cycling life. However，battery thermal runaway frequently causes fire accidents，so battery safety research is of great importance and urgency. Separator as one of the key components of the lithium-ion battery plays a crucial role in the safe operation of the battery. The development of high temperature resistant separators with excellent properties，such as high mechanical strength，low thermal shrinkage，and good self-extinguishing，can significantly enhance the safety of batteries at high temperatures. This paper systematically reviews the latest research progress in the development of high-temperature resistant separators for lithium-ion batteries，including the modification of commercial polyolefin separators and the structural and performance studies of three common high-temperature resistant separators （polyacrylonitrile，polyvinylidene fluoride，and aramid fiber）. The characteristics parameters of separators，such as thickness，porosity，ionic conductivity，and thermal shrinkage，are summarized. Finally，the future development direction and opportunities of high-temperature resistant separators are prospected.

Lithium-based batteries （LBBs） are widely used in portable electronic devices and electric vehicles， serving as a pivotal component in both current and emerging energy storage technologies. Lithium-sulfur batteries are considered as the ideal choice for the next generation of high-energy density batteries due to their high energy density （2600 Wh·kg^-1）. Due to the unique long chain structure and high adhesion force of polymer materials， it shows excellent performance advantages in the application of lithium-sulfur battery binder. This paper reviews the latest research progress and application prospect of polymer materials in improving the safety and stability of lithium batteries. The application of polymer materials in modified separators， solid state electrolytes， binders and flame retardants for LBBs is mainly discussed. In addition， the inhibition ability and mechanism of polymer artificial solid state electrolyte interface film and solid state electrolyte on dendrite growth are introduced， and the flame retardant property of polymer and its mechanism as solid state electrolyte are pointed out. Finally， based on the excellent plasticity and chemical controllability of polymers， the potential of high ionic conductivity and interface stability achieved by molecular design in LBBs energy storage is prospected.

In recent years， with the proposed goals of “carbon peaking” and “carbon neutrality”， the rapid development of new energy electric vehicles has led to a soaring demand for lithium ion batteries （LIBs）. However， the widespread use of LIBs inevitably results in a sharp increase in the number of retired batteries， making the efficient recycling and reuse of these waste batteries an urgent issue. LIBs are categorized into four main types： ternary lithium ion batteries， lithium iron phosphate lithium ion batteries， lithium cobalt oxide lithium ion batteries， and lithium manganese oxide lithium ion batteries. Among them， lithium iron phosphate lithium ion batteries stand out for their extensive applications and high recycling potential. Currently， the recycling of waste lithium iron phosphate lithium ion batteries primarily focuses on the recovery of valuable elements from cathode materials， high-value reuse of materials， and the recycling and functional development of anode materials. This paper provides a comprehensive review of recent advances in the recycling and reuse of lithium iron phosphate lithium ion battery materials， highlighting processes such as pyrometallurgical and hydrometallurgical recovery， the regeneration of cathode materials and their innovative applications in catalysts， as well as the reprocessing of waste anode graphite and the preparation of graphite-based functional materials. Finally， combined with the current technical level， the recycling and utilization of lithium iron phosphate lithium ion battery materials are summarized， and it is pointed out that the future direction of lithium iron phosphate lithium ion battery materials recycling should highlight the trend of optimization classification and recycling strategy， innovative recycling technology， comprehensive recycling， in-depth research on recycling mechanism， and optimization of electrode material design. At the same time， the challenges of future recycling technology are complex battery composition， irregular battery shape， electrolyte processing problems， and low recovery rate.

Lithium fluorocarbon batteries have gained widespread application in areas such as implantable medical devices， military application， sensors， wireless devices， and aerospace due to their high energy density， excellent safety performance， and low self-discharge rates. The performance of lithium fluorocarbon batteries is particularly critical in extending the service life of leadless pacemakers. This article reviews the strategies for enhancing the capacity and voltage of lithium fluorocarbon batteries. The following three aspects are mainly discussed：firstly， the advancement of high specific capacity and high voltage fluorocarbon， involving the optimization of carbon source structure， pre- and post-fluorination treatment， and control of fluorination methods； secondly， the development of high-performance electrolytes， including the use of low concentration lithium salts with solvents processing high donor number， as well as reactive lithium salts and solvents； lastly， the optimization of battery manufacturing processes， particularly focusing on thick electrode and electrolyte injection processes. A comprehensive analysis indicates that by meticulously modulating the structure of carbon sources， optimizing the proportion of fluorocarbon bonds， improving electrolyte formulations， and innovating process technologies， it is possible to develop lithium fluorocarbon batteries with higher capacity and voltage， thereby effectively enhancing the service life of leadless pacemakers.

In recent years，sodium-ion batteries have become a research hotspot in the world and are gradually moving toward industrialization. However，they still have shortcomings，including phase transition，structural degradation，and voltage plateau. Therefore，the development of positive electrode materials with better performance plays a crucial role in the capacity and energy density of sodium-ion batteries. This paper meticulously introduces three primary categories of positive electrode materials for sodium-ion batteries： transition metal oxides，polyanions，and Prussian blue. It elucidates the unique advantages of each material in diverse applications，acknowledges their inherent limitations，and presents a range of improvement strategies to address the challenges of low capacity and energy density. Additionally，by examining the investment trends and industrial layouts of sodium-ion battery positive electrode materials，this study analyzes the industrialization pathways and current development statuses of these three systems，summarizing the latest research advancements. Therefore，it is anticipated that with the ongoing maturation of theoretical foundations and industrial advancements，sodium-ion batteries will rapidly develop，and gradually integrate into daily life.

Sodium iron phosphate （NaFePO₄， NFP）， a cathode material renowned for its stable three-dimensional structure and high theoretical specific capacity of 154 mAh·g^-1， stands out as a pivotal component in sodium ion batteries. NFP exists in two distinct crystal structures： triphylite and maricite. The triphylite variety boasts a long lifespan and high reversible capacity， yet its structural thermodynamic instability poses challenges for conventional synthesis methods. Conversely， the maricite structure is stable but exhibits electrochemically inert characteristics due to the absence of cationic transport channels. Both structures suffer from low conductivity and sluggish reaction kinetics， hindering their industrial applications. This paper delves into the characteristics of these two crystal structures and summarizes various synthesis methods， including solid-state， hydrothermal， displacement， and electrospinning， as well as modification techniques such as crystal structure regulation and material surface modification. Additionally， it identifies the key challenges faced by NFP cathodes and presents potential solutions， while also outlining future research directions.

Aqueous zinc-ion batteries （AZIBs） have emerged as a highly competitive and promising new energy storage technology due to their high safety， high theoretical specific capacity， low cost， and simple fabrication process. In recent years， vanadium-based oxide materials have been widely used as cathode materials for AZIBs due to their high theoretical capacity， diverse valence states， and high electrochemical activity. However， challenges such as low electronic conductivity， structural instability， slow kinetics， and complex energy storage mechanisms hinder their further development and application in AZIBs. Recently， with the continuous optimization of electrode materials and the in-depth exploration of electrode reaction mechanisms， researchers discover that defect engineering strategies can effectively address these issues and enhance the electrochemical performance of vanadium-based oxide cathode materials. This review summarizes the zinc storage mechanisms of vanadium-based oxides， explores the research progress of applying defect engineering strategies to vanadium-based oxide cathode materials in aqueous zinc-ion batteries， discusses and summarizes the reasons for the improvement in zinc storage performance， and provides prospects for future research directions in defect engineering. The aim is to promote the development and practical application of high-performance zinc-ion batteries.

Fluorinated and cyanosubstituted lithium sulfonimide （LiFBTFSI and LiCBTFSI） are synthesized from 4-fluorobenzene sulfonyl chloride and 4-cyanobenzene sulfonyl chloride by sulfonylation and ion exchange， respectively. Two PEO based polymer electrolytes （PEO₂₀-LiFBTFSI and PEO₂₀-LiCBTFSI） are prepared by solution casting， and their micromorphology， thermal stability and electrochemical properties are characterized. The results show that at 60 ℃ and EO/Li⁺=20， the ionic conductivity of the two solid electrolyte reaches 10^-4 S/cm， the electrochemical stability window is greater than 5 V， and the battery assembled with lithium iron phosphate has a high initial discharge capacity （0.1 C， ≈150 mAh·g^-1）. Compared with the fluorine PEO₂₀-LiFBTFSI solid electrolyte， the cyan-containing PEO₂₀-LiCBTFSI solid electrolyte has better electrochemical stability and interface compatibility. After 50 cycles， the specific discharge capacity of the battery is 137.4 mAh·g^-1， and the capacity retention rate is 93.0%. In addition， the cyano-containing PEO₂₀-LiCBTFSI solid electrolyte has good electrochemical stability with lithium metal， and the assembled lithium symmetric battery operates stably at a current density of 0.1 mA/cm² for 500 h without short circuit.

Separator modification represents a prevalent approach to inhibiting lithium dendrite growth and enhancing battery safety. In this study， lithium metal serves as the negative electrode， LiFePO₄ as the cathode， and a graphene coating modified polypropylene separator is employed. Lithium batteries are assembled and undergo rigorous testing， including cycling tests， rate capability tests， electrochemical impedance spectroscopy （EIS） measurements， and morphological analysis of the lithium negative electrode before and after cycling. The primary focus is to investigate the influence of positioning the graphene coating towards either the cathode or the negative electrode on battery performance. Cycle performance results indicate that when the graphene coating faces the negative electrode， the battery exhibits an initial discharge-specific capacity of 168 mAh/g at 0.2 C. After enduring 500 cycles， the discharge-specific capacity remains stable at 154 mAh/g， yielding a capacity retention rate of 91.67%. EIS analysis further reveals that the battery with the graphene coating oriented towards the negative electrode exhibits decreased interfacial resistance and improved reaction kinetics. Moreover， the surface of the cycled lithium negative electrode remains smooth and uniform， devoid of significant lithium dendrite formation. Consequently， lithium batteries configured with the graphene coating facing the negative electrode demonstrate superior cycle performance and heightened safety.

Two metal-organic frameworks （MOFs）， Ce-UiO-66， and Zr-UiO-66， are synthesized using cerium ammonium nitrate （Ce（NH₄）₂（NO₃）₆） and zirconium tetrachloride （ZrCl₄） as metal salts， and 1，4-benzenedicarboxylic acid （H₂BDC） as the organic linker. The crystal structure and morphology of the MOFs are characterized by powder X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The MOFs-modified functional separators are prepared by loading Ce-UiO-66 and Zr-UiO-66 onto one side of commercial Celgard PP separators via vacuum filtration. The electrochemical performance of lithium-sulfur batteries is assembled and tested. The results show that the Ce-UiO-66 modified separator batteries demonstrates optimal electrochemical performance. At a rate of 0.2 C， the initial discharge capacity reaches 1047 mAh·g^-1， with a capacity retention rate of 77.5% after 200 cycles and Coulombic efficiency approaching 100%. Under various current rates， the Ce-UiO-66 modified cells deliver discharge capacities of 1281， 945， 768.1， 673.2， 604.7 mAh·g^-1 at 0.1， 0.2， 0.5， 1， 2 C， respectively. When returning to 0.1 C， the capacity recovers to 951.6 mAh·g^-1 with a capacity retention rate of 74.3%. The above results demonstrate that the redox-active Ce₆-oxo clusters in Ce-UiO-66 can effectively catalyze the conversion reactions of lithium polysulfides （LiPSs） and enhance the redox kinetics. Furthermore， Ce-UiO-66 possesses abundant defects and unsaturated coordination sites， which can effectively anchor LiPSs， mitigate the shuttle effect， and further enhance the electrochemical performance of batteries.

The sulfonated branched polybenzimidazole （sb-PBI） membranes with theoretical sulfonation degrees of 30%，40%，50%，and 60% are prepared by reacting between synthesized branched polybenzimidazole and 1，4-butane sultone for application in all-vanadium flow battery （VFB）. Among them，the sb-PBI-50 membrane shows excellent vanadium ion resistance （9.34×10^-9 cm²/min），proton conductivity （2.05×10^-2 S/cm），and selectivity （2.20×10⁶ S·min/cm³）. The coulomb efficiencies （96.26%-98.35%），voltage efficiencies （73.50%-90.19%），and energy efficiencies （71.72%-86.82%） of VFB with sb-PBI-50 membrane are higher than those of commercial Nafion 212 membrane under the current density of 80-280 mA/cm². In addition，the VFB assembled with sb-PBI-50 membrane can stably carry out 1170 charge-discharge cycles at 140 mA/cm². The chemical structure and micro-morphologies can remain stable after long-term cycles，indicating that the sb-PBI-50 membrane has good application potential in VFB.

In light of the “rich coal，poor oil，and scarce gas” resource status in China，developing carbon electrode materials from coal can accelerate the transformation of clean and efficient utilization of coal and the realization of “dual carbon” goals. Herein，the porous carbon is synthesized from Shenmu bituminous coal via a one-step KOH activation strategy. The results indicate that the resultant carbon possesses a hierarchical porous structure with a surface area of 2094.5 m²·g^-1 and pore volume of 0.96 cm³·g^-1，abundant graphitized microcrystals，N/O co-doping，and excellent hydrophilicity. By employing as-fabricated carbon as cathode，2 mol·L^-1 ZnSO₄ aqueous solution as electrolyte，and Zn foil as anode，the assembled coin-type Zn-ion hybrid supercapacitors （ZIHSCs） exhibit a high capacity of 178.7 mAh·g^-1 at 0.1 A·g^-1 and retain 89.2 mAh·g^-1 by enlarging the current density 200 times to 20 A·g^-1，manifesting an eminent rate performance. Importantly，the maximum energy density and power density of ZIHSCs can reach 142 Wh·kg^-1 and 16854.9 W·kg^-1，respectively. Furthermore，the quasi-solid ZIHSCs based on the gel electrolyte of gelatin@ZnSO₄ also deliver outstanding electrochemical capability and excellent flexibility.

Different crystal forms of manganese dioxide （MnO₂） are synthesized using KMnO₄， MnSO₄·H₂O， （NH4）₂S₂O₈， and hydrochloric acid as raw materials by precisely controlling the temperature and duration of a hydrothermal reaction. The structure and morphology of the materials are characterized using XRD， SEM， and TEM. The results show that the synthesized MnO₂ nanoparticles display different microscopic morphologies depending on their crystal forms. A comparison of their electrochemical performances indicates that δ-MnO₂， due to its unique flower-like structure， provides many reaction sites， leading to superior performance compared to other crystal forms of manganese dioxide. At a current density of 2 A/g， δ-MnO₂ achieves a capacity of 623.48 mAh/g after 1400 cycles. The kinetic properties of the MnO₂ electrode are investigated using cyclic voltammetry， electrochemical impedance spectroscopy， and constant current intermittent titration techniques. It reveals that δ-MnO₂ exhibits a higher Li⁺ diffusion rate.

Sodium-ion batteries have garnered significant attention owing to their abundant sodium reserves， cost-effectiveness， and operational principles akin to lithium-ion batteries， exhibiting immense potential for large-scale energy storage applications. The advancement of sodium-ion batteries with rapid charge-discharge capabilities can effectively cater to frequency modulation needs in large-scale energy storage systems. As a pivotal component， the electrolyte in sodium-ion batteries plays a crucial role in electrode/electrolyte interface reactions and significantly influences the fast-charging characteristics of these batteries. This paper delve into the opportunities and challenges associated with fast-charging electrolytes in sodium-ion batteries. Furthermore， we discuss the intimate relationship between the fast-charging performance of sodium-ion batteries and the properties of the electrolyte， focusing on the electrolyte’s transmission characteristics and electrochemical stability. Lastly， we summarize the current development status of fast-charging electrolytes based on various solvent systems and propose a general design strategy. The comprehensive analysis presented in this paper offers valuable insights and guidance for the research and development of sodium-ion batteries with rapid charge-discharge capabilities.

Prussian blue analogous compounds （PBAs） have emerged as promising candidates for cathode materials in next-generation sodium-ion batteries （SIBs）， attributed to their inherent thermodynamic stability， expansive ion intercalation/deintercalation pathways， abundant electrochemically active sites， as well as their adjustable chemical compositions and elemental ratios. However， the electrochemical performance of these materials is frequently compromised by crystal defects and high levels of crystalline and interstitial water content. This review delves into the structure of PBAs， categorizing them from both single-electron and two-electron perspectives. It examines the prevalent challenges faced by PBAs， systematically reviewing existing typical modification strategies across six dimensions： crystallinity control， defect mitigation， morphology modulation， ion doping/substitution， component optimization， and carbon coating/compositing. Furthermore， it offers insights into the current status of PBAs in transitioning from laboratory research to industrial applications. Looking ahead， this paper anticipates the development of PBAs in the realm of SIBs， expecting them to advance from the laboratory stage to industrialized applications through advancements in materials engineering and surface science.

With the rapid development of modern technology，there is an increasing demand for energy storage systems that can operate stably in extreme environments，especially in cutting-edge fields such as unmanned aerial vehicles，electric vehicles，and deep-sea exploration. Lithium-ion batteries，due to their high energy density，long life，and lack of memory effect，have become an ideal choice to meet the energy needs in these extreme environments. However，harsh conditions such as extreme temperatures，impacts，and pressures pose serious challenges to the performance and safety of batteries. This article reviews the failure behaviors and mechanisms of lithium-ion batteries in various extreme environments in recent years，focusing on the changes in the internal material structure of the batteries，lithium ion transport，and electrochemical reactions to explore the internal material failure mechanisms of lithium-ion batteries under various extreme conditions. Finally，the article summarizes the main measures to improve the performance of lithium-ion batteries in extreme environments. It is hoped that these studies can guide the design of more durable and efficient lithium-ion batteries in the future，promoting the development of lithium-ion batteries in a wider range of fields.

With the increasing demand for energy storage， higher requirements have been put forward for the cycle life， capacity， working stability， and rate performances in batteries. Lithium-ion batteries （LIBs） are favoured for their excellent electrochemical performance and broad development prospects and have been widely applied in mobile devices， electric vehicles， and other fields. However， the bottleneck factors such as life decay and high cost have hindered the further promotion and application of LIBs. This article reviews the main factors affecting the cycle life decay of LIBs， including damage and gas production of positive electrode materials， as well as the consumption of active lithium caused by the repair of negative electrode solid electrolyte interface （SEI） membrane and the formation of lithium dendrites. Effective ways for scientific researchers to improve the life properties of LIBs in recent years， including the structural design of negative electrode materials and the control of SEI film stability， as well as ion doping and surface coating of positive electrode materials， are also summarized. Finally， the future development trends in this field from three aspects， such as multi-element doping， uniform coating new technology， and stable SEI film control are proposed based on the bottleneck issues in the development of lithium-ion batteries.

Lithium-ion batteries have been a crucial and indispensable energy storage system in the energy technology. Developing Li-ion batteries with high energy density，extended cycle life，and cost-effectiveness is a central challenge. Silicon material，distinguished by its impressive theoretical capacity of 4200 mAh·g^-1 and low price，has emerged as a promising candidate for negative electrode material. However，its substantial volume expansion，reaching up to 300% during charging and discharging cycles，poses a formidable commercial hurdle. To date，three generations of silicon-carbon negative electrode materials have undergone iterative development. This review focuses on three generations of silicon-carbon negative electrode materials fabricated via the CVD method. The material structure design，experimental methodologies，reaction mechanisms，and material properties are analyzed. The strengths and weaknesses of these three generations of preparation techniques are summarized，and insights into the future direction of silicon-carbon negative electrodes in Li-ion batteries are provided.

With the development of portable electronic devices and electric vehicles， the energy density of traditional lithium-ion batteries is approaching their theoretical limit. The research on lithium metal batteries with high energy density has been re-focused. However， the high reactivity of lithium increases safety risks and reduces energy density when excess lithium is used. Anode-free lithium metal batteries （AF-LMBs） have emerged as a solution. AF-LMBs possess high energy density and the lowest redox potential. But they have poor cycle life， limited active materials， and complex interfacial reactions. Improving the cycle stability of AF-LMBs is key to realizing the application of high-energy-density storage systems.This paper reviews the development of AF-LMBs and analyzes in depth the current challenges they face from four aspects： lithium dendrites， electrolyte stability， solid electrolyte interface （SEI）， and current collectors. These factors together affect the cycle stability， safety， and energy density of AF-LMBs. Finally， it is pointed out that the future research directions should focus on optimizing electrolyte formulations， designing artificial SEI layers， and improving current collector materials and structures. Meanwhile， paying attention to the volumetric energy density of batteries to meet the demand for compact and efficient energy storage systems in practical applications， thereby promoting the commercialization of AF-LMBs.

The effect of Pt catalysts with varied carbon supports on the performance of membrane electrode assembly （MEA） in proton exchange membrane fuel cell is different. In this study， graphene and Vulcan XC-72 supported Pt catalysts （Pt/G and Pt/C） are prepared respectively， and their morphology and physical properties are characterized. As cathode catalysts of MEA， the effects of Pt/G and Pt/C on the performance of MEA at varied I/C ratios are investigated by polarization curve performance test and electrochemical impedance spectroscopy test. The cyclic voltammetry curve test and accelerated stress test are carried out to further evaluate the influence of Pt catalysts with different carbon supports on the stability of MEA in the fuel cell operating environment through the changes in the electrochemical active surface area and polarization curve. The results show that the optimal I/C ratios of Pt/G and Pt/C are 0.5 and 0.6， respectively. With the increase of Pt loadings， the polarization curves show a trend of first increasing and then decreasing， and the maximum value is 0.8 mg_Pt/cm². After 30000 triangular wave cycles， the ECSA loss rate of Pt/G is 63%， and the peak power retention rate is as high as 60%. Compared with Pt/C， graphene is a MEA catalyst carrier with better stability than amorphous carbon Vulcan XC-72.

IC21 alloy， as a new Ni₃Al-based single crystal superalloy， has become an ideal material for manufacturing a new generation of aero-engine turbine guide vanes due to its high melting point， excellent high-temperature performance， and creep resistance performance. However， turbine guide vanes have complex structures， such as deep holes and deep and narrow slots， which are difficult to be processed efficiently by traditional machining techniques. Electrochemical machining has become the main method for processing such complex structures due to its advantages， such as no tool loss， high material removal rate， and no cutting stress and thermal effect. This paper focuses on the electrochemical dissolution behavior of IC21 nickel-based single crystal alloy in NaCl and NaNO₃ electrolytes. The electrochemical reaction characteristics of IC21 alloy in different electrolytes are analysed by linear scanning voltammetric polarisation curve measurements. In addition， the dissolution characteristics and selective dissolution phenomena of the alloy under different electrolytes and current densities are investigated by current efficiency measurements and surface micro-morphology analysis. It is shown that IC21 alloy exhibits typical passivation-super-passivation transition phenomena in both NaCl and NaNO₃ electrolytes， in which the oxide layer formed in NaNO₃ electrolyte exhibits higher stability. Current efficiency measurements show that the dissolution efficiency of IC21 alloy is more stable in NaCl electrolyte， and the dissolution efficiency in NaNO₃ electrolyte gradually decreases with the increase of the current density， which exhibits different characteristics from the traditional theory. The dissolution surface morphology analysis further reveals the existence of the selective dissolution phenomenon of IC21 alloy under ECM conditions， and its microscopic mechanism is discussed. Based on the above experimental results， a theoretical model of electrochemical dissolution of IC21 alloy under different electrolyte and current density conditions is established， which provides a theoretical basis for the development and application of ECM processes for IC21 alloy.

Orthogonal experiments have been carried out to study the optimal process conditions for the preparation of sargassum-based activated carbon with different impregnation ratios， impregnation times， activation temperatures， and activation times based on the self-templated “egg-box” structure using sargassum as the raw material and ZnCl₂ as the activator. The characterization of N₂ adsorption， SEM， and XRD investigate the pore structure properties， surface morphology， and crystal structure of the activated carbon. The electrochemical properties of sargassum-based activated carbon are tested. The optimum process conditions for preparing high specific capacitance activated carbon are analyzed by orthogonal experimental method and obtained as follows： impregnation ratio is 3， impregnation time is 2 h， activation temperature is 700 ℃， and activation time is 2 h. Under nine sets of experimental conditions， the prepared activated carbon SAC₇ exhibits the best electrochemical performance， the specific capacitance of activated carbon SAC₇ is as high as 136.4 F/g when the current density is 0.5 A/g， and its specific capacitance is as high as 92.0 F/g when the current density is 5 A/g， which shows a superior specific capacitance and rate performance. After 10000 cycles of charging and discharging， the SAC₇ still has a capacitance retention rate as high as 99.41%， with excellent cycling stability.

To promote the large-scale commercial application of fuel cells， efficient， stable， and low-cost oxygen reduction reaction （ORR） catalysts should be developed. In this study， a Fe-doped ZIF-8 is used as the precursor， and the Fe-N-C non-precious metal catalyst is obtained by ball milling， calcination under a high-temperature argon atmosphere， pickling， and secondary calcination under an ammonia atmosphere. The results of various characterization methods show that Fe atoms are uniformly dispersed on the nitrogen-doped carbon framework， thus forming abundant Fe-N _x active sites. The electrochemical performance test results show that the Fe-N-C-5% catalyst with optimized preparation process and metal contents exhibits excellent ORR activity in 0.1 mol/L HClO₄ acidic solution， with a half-wave potential of 0.845 V. Meantime， it has good stability， and the half-wave potential does not drop significantly after 20000 cycles. These results provide an effective strategy for the rational design of precious metal-free ORR catalysts in the future.

Flexible energy storage devices made from natural fiber braids have garnered significant attention due to their abundant availability， low cost， and mature and reliable structural design. However， these natural fiber materials typically suffer from low specific surface area and energy storage density. To address this issue， this study employs a multi-step treatment method， such as incorporating high-temperature carbonization， heterogeneous element doping， strong alkali etching， and MXene electrochemical active material coating，to treat commercial cotton fabrics. The effects of these multi-step treatments on the materials are explored through analyses of their chemical composition， microscopic morphology， microporous structure， and energy storage behavior. The results show that after multi-step treatment， the material maintains a good flexible characteristic， realizes the co-doping of N and S elements， and improves the microstructure of the carbon cloth material. Specifically， the average pore size on the surface of the carbon cloth decreases from 36.44 nm to 2.03 nm， while its specific surface area increased dramatically from 1.78 m²/g to 1043.37 m²/g， representing an increase of 58516%. Additionally， the total pore volume rises from 0.0162 mL/g to 0.53 mL/g. Following complex treatment， the carbon cloth achieves high specific capacitance of 530.83 F/g. However， the material still faces challenges regarding poor rate capability and unstable energy storage performance， which require further improvement in subsequent studies. This research outlines directions and provides technical and theoretical references for enhancing the energy storage performance of flexible carbon-based materials.

Emerging energy storage technologies must meet the requirements of low cost， reasonable safety， rich natural resources and high energy density. The rechargeable magnesium sulfur （Mg-S） battery has the advantages of high energy density， high safety， low cost，and so on. However， its performance is limited by self-discharge， rapid capacity loss， magnesium anode passivation，and low sulfur utilization. The recent advances in Mg-S battery research， focusing on the advances in non-nucleophilic electrolytes， anodes，and cathodes， summarizing electrolytes that can facilitate reversible deposition and dissolution of magnesium ions，and maintaining compatibility with sulfur cathodes and other battery components are reviewed in this paper. In addition， the current challenges of magnesium-sulfur batteries are discussed in the context of research trends， such as the dissolution and diffusion of sulfides and the slow reaction kinetics of Mg-S batteries， as well as recommendations for the future， such as doping MOFs with different elements and exploring the reaction mechanism of the batteries.

To investigate the relationship between calendaring temperature and the microstructure and performance of cathode for Li-ion batteries （LIBs）， two kinds of cathodes at calendaring temperatures of 25 ℃ and 150 ℃ were prepared by two-high rolling mill， respectively. The effects of calendaring temperature on microstructure， thickness consistency， mechanical， and electrochemical properties of cathode were studied. The results show that with the increasing calendaring temperature， the compaction density of cathode coating particles increases significantly， the pore size is smaller， the carbon adhesive phase is uniformly distributed on the active particles， the coating particles are broken， cracks， holes， and other defects decrease， and the cathode structure of conductive/bonding network is easier to form. Compared with the room-temperature calendaring cathode， the thickness consistency of hot calendaring cathode is improved， the rebound rate is reduced by 50%， and the pole sheet bond strength increases from 182.77 N/m to 237.37 N/m， increasing 29.87%. The tensile strength increases from 20.47 MPa to 24.44 MPa， increasing 19.39%. The electrode resistivity decreases from 158.05 Ω·cm to 119.41 Ω·cm， decreasing 24.45%. The electrical conductivity increases from 0.63 S/m to 0.84 S/m， increasing 33.33%. After being assembled as LIBs， the electrochemical performance of the hot calendaring cathode is better than that of the room-temperature calendaring cathode. The cycling capacity retention increases by 18.65%. The cathode performance can be improved moderately by adjusting the calendaring temperature and other technological parameters， providing a research basis for optimizing cathode performance during the LIBs electrodes industrial preparation.

The applications of wearable sensors in sports， medicine， rehabilitation， and other fields， have greatly facilitated the capture and monitoring of human movement index signals effectively avoiding sports injuries， reducing the frequency of medical treatment， and even saving many lives. With the application and popularization of wearable sensors， suitable flexible energy supply systems are the key to its development. In recent years， researchers have studied and designed a variety of flexible energy supply systems based on different energy release methods， among which flexible Zn-ion batteries stand out due to their high energy density， high elastic modulus， high cycle stability， and high safety. We reviewed the research progress in flexible Zn-ion batteries for wearable sensors， mainly introducing and summarizing the batteries components （such as current collector， electrode （cathode and anode）， separator， electrolyte， and packaging） and the application of wearable sensors. Finally， the current problems and challenges of flexible Zn-ion batteries are discussed.

Polymer solid electrolytes have advantages such as high safety， large flexibility， rich variety and low price， laying the foundation for the industrialization of high energy density lithium metal batteries. However， due to the limitations of interface and other problems， the electrochemical performance of polymer solid electrolytes is still poor. In recent years， the in-situ technology has received more and more attention in the field of electrolyte research and development. In-situ technology represented by in-situ polymerization and in-situ characterization has greatly promoted the research of polymer solid electrolytes. In-situ polymerization improves the electrochemical performance of batteries by optimizing electrode and electrolyte interface， and in-situ characterization can explore the electrochemical mechanism inside battery without damage. The historical development of polymer solid electrolytes and in-situ technology was reviewed in this paper. The development and application of in-situ polymerization in various types of polymer solid electrolytes in recent years were discussed， as well as the use of in-situ characterization in in-situ polymer electrolyte preparation. The in-situ technology has great application prospects in the preparation and the characterization of polymer solid electrolytes was pointed out. Simultaneously， several recommendations about focusing on mechanism research，developing new initiation conditions and reaction are proposed to address the problem of the difficulty in controlling the degree of polymerization and the lack of design of matrix structure in in-situ polymerization.

With the rapid development of information technology，electrification and new energy technologies， portable electric devices，electric vehicles and energy storage facilities require rechargeable batteries with higher energy density.However， the energy density of widely used lithium-ion batteries is approaching the limit， which cannot meet the above demands. Therefore it is urgent to explore new electrochemical systems with higher energy density. Lithium metal anode is a promising candidate for achieving next-generation high-energy-density batteries due to its ultrahigh theoretical capacity （3860 mAh·g^-1） and most negative electrochemical potential （-3.04 V vs SHE）. However， during the few decades， the practical application of lithium metal batteries has been hindered by short lifetime and safety issues. In this paper， the history and development of lithium metal batteries were introduced， and the current issues and corresponding mechanisms were analyzed， such as high reactivity， lithium dendrites， dead lithium and volume expansion. Some strategies to deal with the above problems in terms of interface and bulk structure design， including the protection layers formed ex situ/in situ， lithium-based alloys and 3D composite lithium metal anodes，were proposed. Finally，the future developments of practical lithium metal anodes based on constraints for actual batteries， crosstalk of electrodes and failure mechanisms of large-capacity batteries were discussed.

Zinc-ion capacitor is a hybrid supercapacitor consisting of a battery-type negative electrode and a capacitor-type positive electrode， which has the advantages of high energy density， high power density， high safety， and low cost. Its energy density is still limited by the energy storage capacity of the positive electrode material. Therefore， how to design the positive electrode material with high specific capacitance is the key issue to improve the energy density of zinc-ion capacitors. Firstly， the development history， device structure and principles of zinc-ion capacitors were briefly summarized. Moreover， the reasons that limit the application of zinc-ion capacitors were analyzed. Secondly， the device performances， advantages， and shortcomings of typical carbon-based materials and pseudocapacitive materials as positive electrode materials were systematically summarized. Subsequently， the representative research work was chosen to summarize the design strategies and research progress of the positive electrode materials， including nanostructure design， composite material construction， and heteroatom doping. Finally， the development prospects of the positive electrode materials were discussed. It is pointed out that specific research directions are presented， including in-depth research and discovery of new electrochemical mechanisms， the development of new high-performance positive electrode materials，the exploration of effective modification strategies of carbon materials， and the development of functional （such as flexible） electrode materials. These perspectives can provide important ideas for the preparation of positive electrode materials with excellent electrochemical performance.

Lithium-ion capacitors （LICs） are novel power energy storage devices， which have the advantages of both lithium-ion batteries and electric double-layer capacitors. However， the slow electrochemical dynamics of the battery-type anode limits the application of LICs. Metal selenides have attracted much attention because of their excellent conductivity， rapid reaction kinetics and high theoretical capacity. In this paper， the classification， structure and properties of metal selenides are systematically introduced， and three energy storage mechanisms of intercalation mechanism， conversion mechanism and alloying mechanism are discussed.Finally， the impacts of structural regulation， carbon material synergy， and bimetallic selenide construction on the electrochemical performance are analyzed. The application of metal selenide materials with structurally stable and high ion/electron transport capability prepared by the three modification methods is introduced in lithium-ion capacitors.

With the development of miniaturized wearable electronics，flexible energy storage devices with soft，flexible，small size，and high energy density have attracted widespread attention. Aramid nanofibers (ANF) were utilized as fiber reinforcement and pillared structure materials to prepare MXene/ANF flexible self-supporting electrode through vacuum filtration, which were subsequently assembled into all-solid-state symmetric supercapacitors.With the increase of ANF content to 15%，the mechanical properties of MXene/ANF self-supporting electrode increase to 151.5 MPa，while the conductivity decrease to 1371.1 S/cm. The MXene/ANF Self-supporting electrode shows a high specific capacitance of 432.7 F/g at the current density of 1 A/g. The assembled symmetric all-solid-state supercapacitors exhibit excellent mechanical flexibility and remarkable cycling stability,with an energy density of 25.7 Wh/kg at the power density of 523.1 W/kg and about 88.9% capacitance retention over 10000 cycles.

The diblock copolymer electrolyte PEGMEMA _m -GMA _n -Br （PGA-Br）， a copolymer of poly（ethylene glycol methyl ether methacrylate） （PEGMEMA）， and glycidyl methacrylate （GMA） were synthesised by designing the molecular structure of the polymer and using thermally-initiated free-radical polymerisation. The electrochemical performance were investigated. The results show that the ionic conductivity of polymer electrolyte is improved by PGA block or grafting on polymer electrolyte， and the ionic conductivity at room temperature reaches 1.05×10^-4 S·cm^-1. At the same time， PGA-Br block copolymer electrolytes exhibit a low glass transition temperature （-65 ℃）， a high thermal decomposition temperature， an electrochemical stability window of up to 5.1 V， and flame-retardant property. The Li|Li symmetrical solid-state battery assembled with PGA-Br copolymer electrolyte exhibits an enhanced electrode/electrolyte solid-solid interface， which can achieve uniform deposition of lithium metal and effectively inhibit the lithium dendrites growth. The LiNi_0.8Co_0.1Mn_0.1O₂ （NCM811） |PGA-Br|Li solid-state battery based on PGA-Br block copolymer electrolyte can achieve a high first cycle discharge specific capacity of 160.1 mAh/g at 0.1 C， and the capacity retention rate is as high as 91.5% after 100 cycles， and with a stable Coulombic efficiency of over 98.5%.

Sweat contains many physiological information about the body, such as electrolytes, metabolites, hormones, temperature, etc. Sweat-based wearable sensors enable real-time, continuous, non-invasive monitoring of multimodal bio-metrics at the molecular level, and are widely studied for their significant potential in areas such as motion sensing, disease prevention, and health management. This paper described the five modules of substrate, sweat collection, sensing, power supply and decision making in the integrated structure of wearable sweat sensors, highlighted the excellent performance and applications of nanostructures (such as metal-based and carbon-based materials) in electrochemical sensing sensitive materials, and finally discussed the challenges of wearable sweat sensors in terms of trace sweat collection and variability of physicochemical variables in multi-parameter sensing, meanwhile, future directions of wearable sweat sensing are proposed for two key problems of sweat collection and real-time calibration, including bionic microfluidics and multi-parameter feedback regulation methods to achieve efficient collection and accurate detection of microscopic sweat, promote the application and development of real-time early warning of sweat sensing for chronic major diseases.

With the development of the Internet of Things， the rapid development of miniaturized self-powered electronic products and further micro-modulation greatly stimulate the urgent demand for microscale electrochemical energy storage devices. In each electrochemical energy storage device， the supercapacitor based on the plane pattern shape is highly compatible with modern electronic products in terms of functional features such as miniaturization and integration. In this work， the flexible 3D interdigital electrode symmetric micro capacitor was prepared by the combination of semiconductor preparation technology and electrophoresis printing technology， and the 3D printing was carried out by using oxygen enriched activated carbon ink. The 3D interdigital symmetric electrode was prepared by adjusting and optimizing the electric field strength， line width， number of printing layers and other parameters. The energy dispersive spectrometer （EDS）， scanning electron microscopy（SEM），rheometer，electrochemical workstation and test system were used to characterize materials， pastes and microcapacitor devices， and to explore the influence of materials and pastes on the performance of 3D interdigital microcapacitor. The results that the 3D interdigital supercapacitor prepared by the combination of semiconductor and electrophoresis printing process has good performances， and its area capacitance can reach 22.3 mF·cm^-2. In addition， the device can achieve 96% capacity retention after 2000 cycles through packaging optimization. This simple and controllable 3D jet printing technology provides an effective way to prepare advanced miniaturized electrochemical energy storage devices.

Lithium-ion capacitors are energy storage devices between lithium-ion batteries and supercapacitors, which have both high energy density and high power density, and are considered as one of the most promising energy storage systems. In this paper, the research progress of carbon-based and lithium-embedded cathode materials in recent years was summarized, and the classification and modification methods of carbon-based and lithium-embedded electrode materials were introduced in detail. In order to further improve the performance of lithium-ion capacitors, researchers further optimized the cathode materials by means of microstructure regulation, surface modification, doping modification and composite materials, and carried out cathode and anode dynamic matching to comprehensively improve the electrochemical performance of lithium-ion capacitors. Finally, the research hotspots and development directions of cathode materials for lithium-ion capacitors in the future were reviewed in order to provide good electrochemical properties for the next generation of cathode materials for commercial applications.

Considering that a personal car spends about 95% of its life in parking mode, calendar aging can have a significant impact on battery life. High temperature storage is a common method for rapid evaluation of battery calendar life. In order to obtain reliable results of high temperature accelerated aging test, it is necessary to study the aging mechanism of battery stored at different temperature conditions. In this paper, the calendar aging experiment of graphite-SiO_x/NCM811 pouch cells were carried out within the temperature range of 25-55℃. The differential curve analysis and post-mortem analysis were used to explore the aging mechanism. The results show that the calendar aging of pouch cells is mainly caused by the loss of lithium inventory and the loss of cathode active materials. When cells store at higher temperature, the loss of lithium inventory and the loss of cathode active materials increase, while the loss of anode active materials remains relatively unchanged. Based on various test results, it can be inferred that the parasitic reactions on the surface of electrode lead to the loss of lithium inventory and the increase of SEI. With the increase of storage temperature, this side reaction continues and consumes more lithium inventory. It is worth mentioning that when storage at 55℃, the microcracking develops and even breaks some of the secondary particles of cathode materials. Therefore, the pouch cells suffer severe loss of cathode active materials, which makes it inappropriate to accelerate the aging of batteries at such high temperature.