Structural Design of Composite Polymer Electrolytes for Solid‐state Lithium Metal Batteries

Abstract Composite polymer electrolytes with good safety and improved electrochemical performance have attracted widespread attention. However, the ion conduction ability at room temperature and interface compatibility between the electrolyte and electrode still face huge challenges, which greatly hinders the overall performance of solid‐state batteries. Therefore, the focus of this review is on the impact of the composite electrolyte structure on its ion conduction ability and interfacial compatibility, including physical contact of the electrolyte with electrodes, formation of lithium dendrites and space charge layer, adapting to high‐voltage cathode, as well as corresponding solving strategies. Moreover, the structural design‐based ion transport mechanism is highlighted, and the inorganic component with 0D, 1D, 2D, 3D and vertical structure are summarized. The purpose here is to outline the problems and challenges in structural design of composite electrolytes and their interfacial compatibility with various electrodes, allowing for target‐oriented research for high performance solid‐state lithium metal batteries.