中科院化学研究所文锐团队揭示了准固态锂电池LiNi0.5Co0.2Mn0.3O2表面阴极界面层的动态演变过程。 该研究成果于2020年11月29日发表在国际一流学术期刊《美国化学会志》。

深入了解阴极材料的表面机理，例如充电/放电时的结构转化以及化学和机械稳定性，对于设计未来的先进固态锂电池（SSLBs）至关重要。

研究人员通过原子力显微镜的原位观察，研究了工作的SSLB内部LiNi0.5Co0.2Mn0.3O2阴极粒子表面的动态演化过程。通过对Derjaguin-Muller-toprov模量的原位扫描，实时成像了具有无机-有机杂化结构的阴极界面层的动态形成过程及其力学性能的演变。在循环的不同阶段，对阴极界面层的不同组分，如LiF，Li2CO3，以及特定的有机物进行了详细的鉴定，这成分与电池的阻抗存在直接的关系。此外，过渡金属的迁移和新相的形成会进一步加剧SSLB的降解。相对稳定的阴极界面相是提高SSLBs性能的关键。

该文的发现为阴极界面层的表面形态，化学成分和机械性能的动态演变提供了深刻的见解，这对于SSLBs的性能优化至关重要。

附：英文原文

Title: Dynamic Evolution of a Cathode Interphase Layer at the Surface of LiNi0.5Co0.2Mn0.3O2 in Quasi-Solid-State Lithium Batteries

Author: Hui-Juan Guo, Huai-Xiang Wang, Yu-Jie Guo, Gui-Xian Liu, Jing Wan, Yue-Xian Song, Xin-An Yang, Fei-Fei Jia, Fu-Yi Wang, Yu-Guo Guo, Rui Wen, Li-Jun Wan

Issue&Volume: November 29, 2020

Abstract: Intensive understanding of the surface mechanism of cathode materials, such as structural evolution and chemical and mechanical stability upon charging/discharging, is crucial to design advanced solid-state lithium batteries (SSLBs) of tomorrow. Here, via in situ atomic force microscopy monitoring, we explore the dynamic evolution process at the surface of LiNi0.5Co0.2Mn0.3O2 cathode particles inside a working SSLB. The dynamic formation process of the cathode interphase layer, with an inorganic–organic hybrid structure, was  real-time imaged, as well as the evolution of its mechanical property by in situ scanning of the Derjaguin–Muller–Toporov modulus. Moreover, different components of the cathode interphase layer, such as LiF, Li2CO3, and specific organic species, were identified  in detailat different stages of cycling, which can be directly correlated with the impedance buildup of the battery. In addition, the transition metal migration and the formation of new phases can further exacerbate the degradation of the SSLB. A relatively stable cathode interphase is key to improving the performance of SSLBs. Our findings provide deep insights into the dynamic evolution of surface morphology, chemical components and mechanical properties of the cathode interphase layer, which are pivotal for the performance optimization of SSLBs.

DOI: 10.1021/jacs.0c09602

Source: https://pubs.acs.org/doi/10.1021/jacs.0c09602