锂离子电池正极材料本体结构演变及界面行为研究方法

Methods of investigating structural evolution and interface behavior in cathode materials for Li-ion batteries

储能需求的不断增加,要求储能设备拥有更大的容量,而锂离子电池则在储能领域被寄予厚望。正极材料的结构稳定性及储锂电压直接决定了电池的比能量和比功率,其研究一直是锂离子电池研究的核心问题,近些年引起了人们的广泛关注,尤其是材料的结构和电化学行为的实时-原位表征研究对开发和设计性能更为优异的材料有极大的促进作用。对正极材料而言,我们希望获得微观结构形态、化学组分、离子价态变化、外观形貌、离子输运和电子迁移等特性信息以便于进行更为有效的材料制备、结构设计和改性预处理。本综述对表征方法的原理、表征技术使用的场景和相对应的信息等都做了一定的阐述,同时列举了近年来相关技术在锂离子电池正极材料研究中的一些应用。最后则对比讨论了当前表征技术的优缺点,说明了其在研究工作中面临的主要挑战。因此,本文总结了当前对正极材料的结构以及表-界面行为表征常用的技术,包括显微成像、结构与物相、组分与化学价态、成键与官能团的表征,为促进不同的表征技术联用和材料系统分析提供参考借鉴。

The increasing demand for energy storage requires energy storage devices to have greater capacity,and there are high hopes for lithium-ion batteries(LIBs)in the energy storage field.Their structural stability as cathode materials and their voltage profiles for insertion/extraction directly determine the specific energy and power densities of the battery system.In recent years,research related to these characteristics has remained the core issue in the LIB research field,particularly the characterization of the material structure and electrochemical behavior.Important real-time and in-situ strategies were employed in designing and developing more types of materials with excellent performance.For the cathode materials,detailed insights,such as their microstructure,chemical composition,ion valence and states,character of morphology,ion transport,and electron transfer,are beneficial in the preparation,structure design and modification of electrode materials.In this review,the operating principles,usage scenarios,and corresponding information of characterization techniques are introduced,and some examples that use these techniques to characterize LIB anode materials are listed.Finally,the advantages and disadvantages of current characterization techniques are compared,and the major challenges in research studies are discussed.Hence,this article summarizes the typically used technologies that are applied in monitoring the structural changes and surface-interface behaviors of cathode materials,including the microscopic imaging,phase analysis,composition and chemical valence,and bonding and functional groups to provide a reference for the combined utilization of various characterization technologies and to promote the development of an ideal electrode material.