镍钴锰酸锂电极材料改性研究进展

镍钴锰酸锂（LiNi_xCo_yMn_1-x-yO₂,NCM）是一种具有高使用容量的三元正极材料,但存在元素混排、相变、热稳定性差、微裂纹等缺陷,导致电池出现容量衰减和安全问题,影响其广泛应用。针对目前三元材料存在的问题,归纳总结了特殊结构与形貌、掺杂、替代、包覆、修饰、复合等改性方法的最新研究进展,探讨了不同方法对材料电化学性能、循环稳定性和安全性的影响,分析比较了不同方法的优缺点。结合材料、电化学、热和力等多学科知识及本课题组利用负热膨胀材料对能源材料改性的研究成果,提出了原位利用电极循环过程中的热调控形变和界面行为改善材料性能的新思路,为解决电池的热失控和应力等安全问题提供参考。

Advances in the Improvement of Lithium Nickel Manganese Cobalt Oxide Electrode Materials

LiNi_xCo_yMn_1-x-yO₂ (NCM) is a ternary cathode material with high practical capacity. However, its wide application is affected by capacity fade and safety problems caused by factors such as mixing elements, phase transition, poor thermal stability, microcracks, etc. Considering current problems of the ternary materials, recent progress in improving methods were reviewed, including special structure and morphology, doping, substituting, coating, modifying, and combining. Effects of different methods on the electrochemical performance, cyclability and safety of NCM were discussed as well as their advantages and disadvantages. Combining multidisciplinary knowledge of materials, electrochemistry, heat, stress, and the improvements of energy materials using negative thermal expansion (NTE) materials in our laboratory, some novel strategies were developed by simultaneously adjusting deformation and interface behaviors via in-situ using the generated heat during cycles, which paves the way for solving the safety problems like thermal runaway and stress of batteries.