Self‐Adaptive Poly(Vinylene Carbonate) Based Electrolytes for Zero‐Pressure and High‐Temperature Solid‐State Lithium Metal Batteries

Abstract Solid polymer electrolytes (SPEs) have attracted significant attention in next‐generation solid‐state batteries (SSBs). However, SPEs‐based SSBs suffer from performance fading and safety concerns at high temperatures caused by the thermal instability and degradation of their electrode/electrolyte interfaces. Herein, a poly(vinylene carbonate‐co‐methyl acrylate)‐based solid polymer electrolyte (PVC‐MA‐SPE) with a highly self‐adaptive structure is designed. The resulting PVC‐MA‐SPE exhibits an ionic conductivity of 4.93 × 10 −4 S cm −1 at 120 °C and high adhesion to electrodes. At zero pressure, solid‐state Li|PVC‐MA‐SPE|LFP batteries maintain 152.6 mAh g −1 discharge capacity and 95.4% capacity retention after 150 cycles at 1C and 120 °C. The mechanism for the improved performance is attributed to the strong intermolecular interaction of the poly(vinylene carbonate‐co‐methyl acrylate) (PVC‐MA) network with volatile molecules. Importantly, the PVC‐MA network not only enables the SPE to tightly contact with electrodes, but also contributes to forming thermally stable SEI/CEI enriched in flexible polymeric components and LiF. These properties result in enhanced interfacial stability at high temperature. This work presents a novel approach to enhance the intrinsic safety of solid‐state batteries at high temperatures.