Synergistic effect of organic plasticizer and lepidolite filler on polymer electrolytes for all-solid high-voltage Li–metal batteries

Abstract

Composite polymer electrolytes (CPEs) combine the advantages of both solid polymer electrolytes (SPEs) and inorganic solid electrolytes and thereby have drawn much attention due to the large demand for batteries with high energy density and safety. PEO is the most popular polymer as a matrix of CPEs; however, it has many shortcomings. PVDF can be considered as a potential matrix, with a wide electrochemical window, flame retardance and high thermal stability; on the other hand, it has always shown low ionic conductivity. Herein, we report PVDF-based CPEs showing a high ionic conductivity of 0.125 mS cm⁻¹ at room temperature and 1 mS cm⁻¹ at 120 °C, a wide electrochemical window and marvelous fire resistance. The high ionic conductivity can be attributed to the synergistic effect of DMF plasticizer and 2D lepidolite filler. The PVDF-based CPEs therefore showed great potential in all-solid Li–metal batteries with high voltage output, high capacity, satisfactory rate capability and excellent electrochemical stability.