Liu Bowen, Hu Naifang, Li Chao, Ma Jun, Zhang Jianwei, Yang Yuan, Sun Deye, Yin Bangxun, Cui Guanglei
Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China.
Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
Angew Chem Int Ed Engl. 2022 Oct 4;61(40):e202209626. doi: 10.1002/anie.202209626. Epub 2022 Aug 23.
Li-rich layered oxide (LLO) cathode materials with high specific capacities could significantly enhance the energy density of all-solid-state lithium batteries (ASSLBs). However, the specific practical capacities of LLO materials in ASSLBs are extremely low due to poor initial activation. Here, scanning transmission electron microscopy with in situ differential phase contrast imaging was first used to study the initial activation mechanism of Li Ni Co Mn O . Li-ion transport heterogeneity was observed in LLO grains and across the LLO/Li PS Cl interface, due to the coexistence of the nanoscale Li MnO and LiNi Co Mn O phases. Consequently, the severely constrained activation of Li MnO during the first charging could be attributed to a nanoscale phase separation in LLO, hindering Li-ion transport through its particles, and causing high impedance in the Li MnO domain/Li PS Cl interface. This study could facilitate interface design of high-performance LLO-based ASSLBs.
具有高比容量的富锂层状氧化物（LLO）正极材料能够显著提高全固态锂电池（ASSLB）的能量密度。然而，由于初始活化较差，LLO材料在ASSLB中的实际比容量极低。在此，首次使用具有原位差分相衬成像的扫描透射电子显微镜来研究LiNiCoMnO的初始活化机制。由于纳米级LiMnO和LiNiCoMnO相的共存，在LLO颗粒内部以及LLO/LiPSCl界面处均观察到锂离子传输的不均匀性。因此，首次充电过程中LiMnO的严重受限活化可归因于LLO中的纳米级相分离，这阻碍了锂离子通过其颗粒的传输，并在LiMnO域/LiPSCl界面处导致高阻抗。该研究有助于高性能LLO基ASSLB的界面设计。
