层状高熵氧化物的修饰改性策略、作用机理及储钠性能研究进展OA

Sodium-ion batteries have garnered considerable attention for large-scale energy storage applications owing to the abundance of sodium resources and their cost-effectiveness.Among the various cathode materials,layered transition metal oxides have emerged as promising candidates because of their tunable crystal structures,relatively high specific capacities,and favorable electrochemical cycling stability.However,these materials often undergo complex phase transitions and irreversible redox reactions during charge-discharge cycling,leading to structural degradation and,consequently,compromised rate capability and cycling stability.To address these challenges,the high-entropy strategy has emerged as an effective compositional design approach.By incorporating multiple metal elements into the transition-metal sublattices,the configurational entropy is significantly enhanced,thereby stabilizing the crystal framework,suppressing detrimental phase transitions,and facilitating sodium-ion diffusion.This review focuses on the emerging applications of layered high-entropy oxides(LHEOs)as cathode materials for sodium-ion batteries and systematically summarizes recent research progress in this field.First,the fundamental concepts and crystal structure types of LHEOs,such as O3-type and P2-type structures,are introduced,and the advantages and disadvantages of different synthesis methods,including solid-state reaction,sol-gel synthesis,and hydrothermal synthesis,are compared.Second,various modification strategies for LHEOs are comprehensively reviewed,including elemental doping(both cationic and anionic),structural design(e.g.,dual-phase structures),surface coating,and vacancy engineering.The corresponding improvements in electrochemical performance and their underlying mechanisms are discussed in detail.Finally,the current challenges and future research directions for LHEOs are summarized,including the limited understanding of their microscopic mechanisms and the limited exploration of anion-doping strategies.