Two‐Dimensional Template Induced Ultradense Solid Polymer Electrolytes for High‐Performance Solid‐State Lithium Batteries

ABSTRACT Solid polymer electrolytes based on PVDF‐HFP (SPEs) hold great promise in the application of solid‐state Li metal batteries (SSLMBs). However, phase‐separation‐induced inadequate mechanical robustness and compromised Li + transport kinetics significantly hinder their industrial application. Herein, negatively charged Ti 0.87 O 2 monolayer nanosheets were introduced as an interconnected template to suppress phase separation and guide the formation of an ultradense PVDF‐HFP electrolyte (UDSPE) with enhanced mechanical properties. Besides, the strong interaction between Ti 0.87 O 2 nanosheets and Li + enables the rapid Li + migration through the interface, resulting in high ionic conductivity (0.87 mS cm −1 ). The homogeneously dispersed LiTFSI facilitates the formation of an inorganic solid electrolyte interphase, thus effectively suppressing interfacial side reactions and enhancing the interface stability. Consequently, the symmetric cell exhibits a 2300 h stable cycling, and the Li||LiFePO 4 full cell with UDSPE demonstrates a stable cycling performance for more than 2000 cycles. Remarkably, Ah level solid state pouch cell with a high energy density of 386 Wh kg −1 was assembled and worked without any liquid addition. This work provides a rational strategy for designing high‐aspect‐ratio nanosheet templates to achieve homogeneous polymer electrolytes and enable high‐performance SSLMBs.