Interface Engineering and Optimization Strategies for High‐Energy‐Density Batteries Based on Polymer Composite Electrolytes

Abstract Polymer composite electrolytes (PCEs) offer significant advantages in enhancing the safety, stability, and energy density of batteries, making them a crucial component for achieving high‐energy‐density energy storage systems. However, one of the primary bottlenecks in improving the performance of PCEs lies in the interface challenge, which can be exacerbated and manifested in interface instability, side reactions, and poor interface compatibility, ultimately leading to a significant decline in ion conduction efficiency and overall battery performance of high‐voltage or high‐energy‐density systems. Therefore, systematically analyzing the critical technical narrowing and proposing targeted solutions under high‐energy‐density conditions is of great significance for advancing the development of next‐generation energy storage systems. Although existing strategies have shown promising results, their applicability in high‐energy‐density batteries remains uncertain. In this work, a comprehensive analysis of the interface challenges associated with high‐energy‐density polymer batteries is performed, the feasibility of existing approaches is evaluated, and practical optimization strategies are proposed to address these critical issues. Moreover, the insights presented here provide valuable guidance for the industrial‐scale production of PCEs, helping to bridge the gap between laboratory innovations and practical applications.