Highly Conductive and Supertough PVDF‐Based Electrolytes with Self‐Defective Fillers for Solid‐State Lithium Metal Batteries

Advanced PVDF-based electrolytes with ceramic-like ion migration behavior, near-separator-level toughness, and excellent oxidation resistance are critical for the practical implementation of solid-state lithium-metal batteries (SSLMBs). However, the superior ion conductivity, robust mechanical property, and wide electrochemical stability usually cannot be achieved simultaneously. Herein, the self-defective silicon (Si) fillers with silicon/silicon oxide (Si/SiO_x,0<x≤2) heterogeneous interfaces are doped into the PVDF matrix to construct the highly conductive and supertough PVDF-based electrolytes. Results reveal that the self-defective Si will spontaneously participate in the Li⁺-solvation state and convert all solvation structure into the Li⁺-[solvent]_x-[anion]_y (x≤y) configuration. The anion-rich Li⁺ coordination environment not only accelerate Li⁺ diffusion rate but also promotes the formation of the anion-dominated bilayer interphase. Meanwhile, the strong Lewis acid-base interaction of PVDF/SiO_x interface effectively suppresses phase separation initiated by uneven solvent evaporation. Benefiting from the modified Li⁺ transport environment and phase regulation, the obtained electrolytes exhibit impressive comprehensive properties, including ionic conductivity of 0.44 mS cm^-1, tensile strength of 16.5 Mpa, and voltage window of 5.07 V. Besides, the Li||Li symmetrical batteries present outstanding cycling under the current density of 0.1 mA cm^-2 (>6200 h), and the LFP||Li batteries exhibit remarkable fast-charging behavior at 10 C with the capacity retention of 82.29%.