Unique Design Strategies for High‐Performance Solid‐State Polymer Batteries

Solid polymer electrolytes (SPEs) are considered a key enabler for high‐safety and high‐energy‐density solid‐state lithium‐metal batteries. However, challenges such as low ionic conductivity, poor interfacial compatibility, and limited thermal stability continue to hinder their practical application. This review explores the interaction mechanisms in SPEs in detail from four aspects—Lewis acid‐base theory, anion vacancies, hydrogen‐bond networks, and phase‐separated structures—and introduces three functionalized design strategies: channel design, high‐entropy design, and flame‐retardant design. We also comprehensively discuss the latest advancements and development potential in artificial interface design and in situ interface design. This article outlines strategies to overcome existing bottlenecks and emphasizes the importance of functional design. By modulating these microinteractions and optimizing design strategies, it will help accelerate the commercialization of high‐safety, high‐energy‐density solid‐state batteries.