Practical Application of All‐Solid‐State Lithium Batteries Based on High‐Voltage Cathodes: Challenges and Progress

Abstract

All‐solid‐state lithium batteries (ASSLBs) have become a recent research hotspot because of their excellent safety performance. In order to better reflect their superiority, high‐voltage cathodes should be applied to enhance the energy density of solid batteries to compete with commercial liquid batteries. However, the introduction of high‐voltage cathodes suffers from many problems, such as low electrochemical stability, inferior interface chemical stability between cathode and electrolyte, poor mechanical contact, and gas evolution. These drawbacks significantly influence the battery performance, even causing battery failure and hindering the commercialization of solid‐state batteries. This paper first reviews the above failure mechanisms of high‐voltage cathode‐based ASSLBs from different perspectives. Then, recent advances in solid‐state electrolytes for ASSLBs are summarized, mainly including polymer solid electrolytes, sulfide solid electrolytes, and oxide solid electrolytes. In addition, the influence of the cathode materials is also highly critical, and strategies to improve electrochemical performance are put forward, which can be divided into coating protection, synthesis modification, and structure improvement. Finally, guidelines for the future development of solid‐state batteries are also discussed.