K 2 C 2 O 4 ‐Modified PVDF Electrolytes for Lithium‐Polymer Batteries: Synergistic LiF Interphase Formation and Mechanical Reinforcement for Dendrite Suppression

ABSTRACT Poly(vinylidene fluoride) (PVDF)‐based polymer electrolytes are promising candidates for lithium‐ion batteries due to their high ionic conductivity, wide electrochemical stability window, and ease of processing. However, PVDF chain scission during cycling often leads to battery failure. This study introduces a straightforward strategy for modifying PVDF using potassium oxalate (K 2 C 2 O 4 ). The resulting composite gel polymer electrolyte (CGPEK‐X) facilitates the pre‐formation of LiF, which enhances lithium‐ion conductivity and promotes uniform lithium deposition. Moreover, the improved mechanical integrity of the composite effectively suppresses lithium dendrite growth. When integrated into LiFePO 4 /Li cells, the optimized K 2 C 2 O 4 ‐doped system demonstrates stable cycling over 200 cycles at room temperature, achieving a discharge capacity of 120.3 mAh g −1 at 1°C. This work presents a novel approach to engineering PVDF‐based electrolytes with balanced mechanical and electrochemical properties, offering valuable insights for the development of high‐performance lithium‐polymer batteries.