An interpenetrating network poly(diethylene glycol carbonate)-based polymer electrolyte for solid state lithium batteries

Abstract

Polycarbonate-based polymer electrolytes possess superior ionic conductivity at room temperature, higher lithium ion transference number and wider electrochemical stability window when compared with conventional poly(ethylene oxide)-based polymer electrolytes. Herein, the poly(diethylene glycol carbonate) dimethacrylate macromonomer (PDEC-DMA) was synthesized and the resultant interpenetrating network IPN-PDEC polymer electrolyte was developed via free radical in situ polymerization for polymer electrolyte Li metal batteries. This IPN-PDEC polymer electrolyte exhibited a decent ionic conductivity of 1.64 × 10⁻⁴ S cm⁻¹ at room temperature and a wide electrochemical stability window (up to 4.5 V vs. Li⁺/Li). The LiFePO₄/IPN-PDEC/Li and LiFe_0.2Mn_0.8PO₄/IPN-PDEC/Li cells delivered excellent rate capability and cycling performance at room temperature. An all solid state lithium battery was also demonstrated by applying the as-prepared solid polymer electrolyte (SPE-PDEC) at a temperature of 100 °C, which displayed a superior cycling performance. Therefore, the IPN-PDEC network is a promising polymer electrolyte for solid state lithium batteries.