Thin Film Type Solid Electrolyte based on PVDF-HFP/LLZO Composite with Enhanced Electrochemical Performance

: Solid electrolytes are a key component necessary for next-generation lithium-ion batteries with high energy density and improved safety. To fabricate such solid electrolytes, it is crucial to address the issues of low ionic conductivity and high interfacial resistance in conventional solid electrolytes. In this study, we propose a novel electrolyte (PVDF-HFP/LLZO/SN, PHLS membrane) based on a composite of Li7La3Zr2O12 (LLZO) nanowires dispersed in PVDF-HFP polymer, which exhibits enhanced ionic conductivity and interfacial stability. By applying solvent heat pressing (SHP) to the fabricated composite electrolyte PHLS-(SHP), we reduced interfacial resistance and internal pores, achieving a high ionic conductivity of 2.06 × 10-4 S/cm at 30°C, a wide electrochemical stability window of 4.5 V (vs. Li/Li+), and stable interfacial stability between the lithium metal and the electrolyte. Electrochemical tests using a lithium symmetric cell, conducted at 0.2 mA/cm2 , confirmed that the composite electrolyte maintained stability for over 150 hours, indicating improved electrochemical performance through the use of our composite-based solid electrolyte.