Progress in the application of polymer fibers in solid electrolytes for lithium metal batteries

Solid state lithium metal batteries (SSLMBs) are considered to be one of the most promising battery systems for achieving high energy density and excellent safety for energy storage in the future. However, current existed solid-state electrolytes (SSEs) are still difficult to meet the practical application requirements of SSLMBs. In this review, based on the analysis of main problems and challenges faced by the development of SSEs, the ingenious application and latest progresses including specific suggestions of various polymer fibers and their membrane products in solving these issues are emphatically reviewed. Firstly, the inherent defects of inorganic and organic electrolytes are pointed out. Then, the application strategies of polymer fibers/fiber membranes in strengthening strength, reducing thickness, enhancing thermal stability, increasing the film formability, improving ion conductivity and optimizing interface stability are discussed in detail from two aspects of improving physical structure properties and electrochemical performances. Finally, the researches and development trends of the intelligent applications of high-performance polymer fibers in SSEs is prospected. This review intends to provide timely and important guidance for the design and development of polymer fiber composite SSEs for SSLMBs.