Polymer Electrolytes for Compatibility With NCM Cathodes in Solid‐State Lithium Metal Batteries: Challenges and Strategies

ABSTRACT Polymer electrolytes (PEs) compatible with NCM cathodes in solid‐state lithium metal batteries (SSLMBs) are gaining recognition as key candidates for advanced electrochemical storage, offering significant safety and stability. Nevertheless, the inherent properties of PEs and interactions at the interface with NCM cathodes are pivotal in influencing SSLMBs' overall performance. This review offers an in‐depth examination of PEs, focusing on design strategies that leverage electron‐group electronegativity for molecular structure adjustments. Furthermore, it delves into the challenges presented by the interface between PEs and NCM cathodes, including issues like poor interface contact, interface reactions, and elevated resistance. The review also discusses a range of strategies aimed at stabilizing these interfaces, such as applying surface coatings to NCM, optimizing the structure of PEs, and employing in situ polymerization techniques to improve compatibility and battery efficiency. The conclusion offers insights into future developments, highlighting the importance of electron‐group optimization and the adoption of effective methods to enhance interface stability and contact, thus advancing the practical implementation of high‐performance SSLMBs.