Interface challenges and research progress toward solid polymer electrolytes-based lithium metal batteries

Solid-state lithium metal batteries (SLMBs) based on solid polymer electrolytes (SPEs) are a promising option for next-generation energy storage systems owing to their enhanced safety and energy density. However, the unstable interfaces resulting from continuous side reactions between electrodes and SPEs during cycling have hindered the practical application of SLMBs. In this review, we first provide an overview of the development and fundamentals of SPEs. Subsequently, the interface issues, factors influencing interface stability, and strategies to stabilize and enhance the compatibilities of the SPEs/electrodes interface are summarized. Finally, we propose perspectives on improving interface contact and stability through effective strategies for practical high-energy SLMBs. This review aims to deepen the understanding of interfacial issues between SPEs and electrodes and provide specific solutions to improve the electrochemical performances of SLMBs.