Deciphering Chemical/Electrochemical Compatibility of Li<sub>3</sub>InCl<sub>6</sub> in 5.2 V High-Voltage LiCoO<sub>2</sub> All-Solid-State Batteries
Zhen Wang, Jiewen Tan, Zhanhui Jia, Jiawu Cui, Xiaowei Wang, Chengyong Shu, Xiangwen Gao, Yuping Wu, Wei Tang
Abstract
Large interfacial resistance is a widely recognized impediment to the advancement of high-voltage, all-solid-state batteries. However, a comprehensive understanding of the fundamental cause behind the interfacial resistance between solid electrolytes and typical layered oxide cathodes has not yet been achieved. Here, we investigated the high-voltage stability of Li 3 InCl 6 and elucidated the underlying interfacial electrochemical reactions between LiCoO 2 and Li 3 InCl 6 . The pairing of Li 3 InCl 6 with LiCoO 2 exhibited a superior capacity retention of 73.6% even at 5.2 V, much higher than 28.2% charged at 4.6 V in lithium-ion batteries after 70 cycles. The enhanced high-voltage stability of ASSBs is attributed to the stable interface formed between LiCoO 2 and Li 3 InCl 6 and the reinforced surface and bulk structure stability. On the other hand, the ultrahigh voltage still causes the partial decomposition of Li 3 InCl 6 and generates interfacial compounds such as InClO and cobalt and indium chlorides/oxides.