High‐Entropy Solid‐State Electrolytes for Rechargeable Batteries: Mechanism, Structural Designs, Characterizations, and Applications

Abstract Rechargeable batteries achieve remarkable advancements over the past few decades. Conventional electrolytes suffer from a range of challenges, such as low conductivity and poor thermal stability. Recent studies show that various properties of high‐entropy solid‐state electrolytes effectively solve these challenges. High‐entropy solid‐state electrolytes emerge as an effective strategy to enhance electrochemical performance. This review provides a comprehensive analysis of the fundamental principles, synthesis strategy, electrical performance characteristics, and applications of high‐entropy solid‐state electrolytes in electrochemical systems. Initially, this review discusses the mechanisms of the high‐entropy solid‐state electrolytes. Then, the optimization of high‐entropy solid‐state electrolytes is systematically introduced. The formation of single‐phase structure improves the battery performance from multiple dimensions. Recent studies indicate that the high‐entropy disorder can effectively enhance the ionic conductivity. A high‐entropy approach promotes a uniform distribution of atoms within the material's lattice structure to improve the stability. The high‐entropy solid‐state electrolytes also mitigate some interfacial issues by the unique characteristics. Finally, this review summarizes the diverse applications of the high‐entropy solid‐state electrolytes. This review aims to offer a general overview of the current status and innovative thinking to support the future research of high‐entropy solid‐state electrolytes.