Electrolyte Developments for All-Solid-State Lithium Batteries: Classifications, Recent Advances and Synthesis Methods

The developments of all-solid-state lithium batteries (ASSLBs) have become promising candidates for next-generation energy storage devices. Compared to conventional lithium batteries, ASSLBs possess higher safety, energy density, and stability, which are determined by the nature of the solid electrolyte materials. In particular, various types of solid electrolyte materials have been developed to achieve similar or even superior ionic conductivity to the organic liquid electrolyte at room temperature. Although tremendous efforts have been devoted to the mechanistic understanding of solid electrolyte materials, the unsatisfactory electrochemical and mechanical performances limit the commercialization and practical application of ASSLBs. To further improve their performances, the current developments of different advanced solid electrolytes and their performances are highly significant. In this review, we summarize the comprehensive performance of the common solid electrolytes and their fabrication strategies, including inorganic-based solid electrolytes, solid polymer electrolytes, and composite solid electrolytes. The performances of the ASSLBs constructed by different solid electrolytes have been systematically compared. The practical challenges of ASSLBs will also be summarized in this review. This review aims to provide a comprehensive review of the current developments of solid electrolytes in ASSLBs and discuss the strategies for advanced solid electrolytes to facilitate the future commercialization of ASSLBs.