Electrolyte and anode‐electrolyte interphase in solid‐state lithium metal polymer batteries: A perspective

Abstract The interest for solid‐state lithium metal (Li°) batteries (SSLMBs) has been growing exponentially in recent years in view of their higher energy density and eliminated safety concerns. Solid polymer electrolytes (SPEs) are soft ionic conductors which can be easily processed into thin films at industrial level; these unique features confer solid‐state Li° polymer batteries (SSLMPBs, i.e., SSLMBs utilizing SPEs as electrolytes) distinct advantages compared to SSLMBs containing other electrolytes. In this article, we briefly review recent progresses and achievements in SSLMPBs including the improvement of ionic conductivity of SPEs and their interfacial stability with Li° anode. Moreover, we outline several advanced in‐situ and ex‐situ characterizing techniques which could assist in‐depth understanding of the anode‐electrolyte interphases in SSLMPBs. This article is hoped not only to update the state‐of‐the‐art in the research on SSLMPBs but also to bring intriguing insights that could improve the fundamental properties (e.g., transport, dendrite formation, and growth, etc.) and electrochemical performance of SSLMPBs.