Ceramic Rich Composite Electrolytes: An Overview of Paradigm Shift toward Solid Electrolytes for High‐Performance Lithium‐Metal Batteries

Abstract Exploiting the synergy between organic polymer electrolytes and inorganic electrolytes via the development of composite electrolytes can suggest solutions to the current challenges of next‐generation solid‐state lithium‐metal batteries (SSLMBs). Depending upon a mass fraction of inorganic fillers and organic polymers, composite electrolytes are broadly classified into “ceramic‐in‐polymer” (CIP) and “polymer‐in‐ceramic” (PIC) categories, inheriting distinct structure and electrochemical properties. Since the stability and electrochemical characteristics of the inorganic phase are superior to those of the organic phase for lithium‐ion conduction, applying lithium‐enrich active filler in PIC seems more promising. The inorganic phase preserves the primary migratory channels in the PIC electrolyte, while the viscoelastic properties attempt to be introduced from the organic binder or host. The present work overviews the studies on state‐of‐the‐art PIC electrolytes, the fundamental mechanism of ionic conduction, preparation methods, and current progress in materials development for SSLMBs. In addition, the modification strategies for improving the electrode–electrolyte interface are also emphasized. Moreover, it further prospects the current challenges and effective strategies for the future development of PICs‐based CPEs to accelerate the practical application of SSLMBs. This review examines the progress and outlook of PIC‐based electrolytes for next‐generation lithium batteries.