In Situ Formed Three‐Dimensionally Conducting Polymer Electrolyte for Solid‐State Lithium Metal Batteries With High‐Cathode Loading

ABSTRACT Low‐ionic conductivity within high‐loading cathode has greatly limited the application of solid polymer electrolytes in rechargeable batteries. Herein, solid polymer electrolyte with a three‐dimensionally conducting network is obtained by in situ polymerization of vinyl ethylene carbonate (VEC) with the aid of dipentaerythritol hexaacrylate (DPHA) crosslinker in the solid‐state lithium (Li) metal batteries (LMBs). The weak coordination of Li + with C═O and C─O groups promotes the dissociation and transport of Li + . The obtained P(VEC–DPHA) electrolyte enables a fast and orderly Li + transport path and hinders the transport of TFSI − , rendering a remarkable ionic conductivity (2.53 × 10 −4 S cm −1 ), high Li + transference number (0.47), and wide electrochemical window (5.1 V). A total of 87.38% capacity retention rate of LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li is achieved after 200 cycles at 0.2 C. P(VEC–DPHA) can also provide stable cycles under harsh conditions of high rate (1 C), high‐cathode loading (10.83 mg cm −2 ), and high‐energy‐density pouch cell (421.8 Wh kg −1 , cathode loading of 25 mg cm −2 ). This work provides novel insights for the design of highly conductive polymer electrolytes and high‐energy‐density LMBs.