Thio‐/LISICON and LGPS‐Type Solid Electrolytes for All‐Solid‐State Lithium‐Ion Batteries

Abstract As an integral part of all‐solid‐state lithium (Li) batteries (ASSLBs), solid‐state electrolytes (SSEs) must meet requirements in high ionic conductivity, electrochemical/chemical stability toward the electrode. The ionic conductivity of the Li super ionic conductor (LISICON) is limited, and the thio‐LISICON is improved by replacing O 2− in the LISICON with S 2− . Currently, the ionic conductivity of Li 10 GeP 2 S 12 (LGPS) has exceeded 10 mS cm −1 , which meets the demands of commercial ASSLBs. However, poor stability of SSEs, baneful interfacial reactions, Li dendrite growth, and other factors have impeded the development of ASSLBs. Hence, this review first traces the development progress of thio‐/LISICON and LGPS‐type SSEs, analyzes the complicated ion transport mechanism, and summarizes the effective strategies for improving ionic conductivity. Moreover, exciting methods focusing on electrode interface engineering are outlined separately. As to SSE/anode interface, poor chemical or electrochemical compatibility, poor interfacial contact, and the mechanisms of dendrite formation are discussed. For the SSE/cathode interface, poor interfacial stability and non‐intimate solid–solid contact are daunting challenges. Then, effective methods to improve interface stability and electrochemical performance of ASSLBs with LGPS‐type SSEs are introduced. Finally, combined with the present chances and challenges, the possible future developing directions of LGPS‐based ASSLBs and the perspectives are proposed.