Challenges and Development of Composite Solid Electrolytes for All-solid-state Lithium Batteries

All-solid-state lithium batteries are considered to be a new battery system with great development potential and application prospects due to the advantages of high energy density and high security. As a key component of all-solid-state lithium batteries, the development of solid-state electrolytes has received extensive attention in recent years, but most solid electrolytes still exhibit problems, such as low ion conductivity and poor interface compatibility. The design of composite solid-state electrolyte materials with both excellent electrochemical and mechanical properties is an effective way to develop all-solid-state lithium batteries. This review introduces different types of pure component solid electrolytes and analyzes their respective advantages and characteristics firstly. Furthermore, the research progress of composite electrolytes in preparation method, ionic conduction, suppression of lithium dendrites, and the improvement of electrochemical performances are reviewed from the perspective of composite electrolyte structure design, which is to meet different performance requirements. And the future development direction and trend of composite electrolytes are prospected.