Sandwich-Like Poly(propylene carbonate)-Based Electrolyte for Ambient-Temperature Solid-State Lithium Ion Batteries

A poly(propylene carbonate) (PPC)-based sandwich like composite solid polymer electrolyte (SE) was designed and applied to solid-state lithium ion batteries at 25 degrees C. The sandwich like structure of the composite SE was composed of three parts. A polypropylene separator was used as a support membrane to enhance the strength of the SE membrane. Succinonitrile in the PPC-based SE was used to increase the ionic conductivity. Pure PPC as a buffer layer was closed to the lithium anode, which could improve the interface compatibility, Coulombic efficiency, and cycle life of batteries. The sandwich-like composite SE exhibited good comprehensive properties such as a high ion transference number (0.65), sufficient ionic conductivity (2.18 X 10(-4) S cm(-1) and 5.77 X 10(-4) S cm(-1) at 25 and 55 degrees C, respectively), and outstanding electrochemical stability at ambient temperature. Furthermore, a Li/LiFePO4 cell with the sandwich-like composite SE delivered a discharge capacity close to 140 mA h g(-1) (0.1 C) at 25 degrees C. The results suggested that a sandwich-like PPC-based electrolyte is a promising SE for solid-state batteries.