Incorporating multifunctional LiAlSiO4 into polyethylene oxide for high-performance solid-state lithium batteries

Abstract

High ionic conductivity, good electrochemical stability, and satisfactory mechanical property are the crucial factors for polymer solid state electrolytes. Herein, fast ion conductor LiAlSiO4 (LASO) is incorporated into polyethylene oxide (PEO)-based solid-state electrolytes (SSEs). The SSEs containing LASO exhibit enhanced mechanical properties performance compared to pristine PEO-LiTFSI electrolyte. A reduced melting transition temperature of 40.57 °C is enabled by introducing LASO in to PEO-based SSE, which is beneficial to the motion of PEO chain and makes it possible for working at a moderate environment. Coupling with the enhanced motion of PEO, dissociation of the lithium salt, and conducting channel of LASO, the optimized composite polymer SSE exhibits a high ionic conductivity of 4.68 × 10−4, 3.16 × 10−4 and 1.62 × 10−4 S cm−1 at 60, 50 and 40 °C, respectively. The corresponding LiFePO4//Li solid-state battery exhibits high specific capacities of 166, 160 and 139 mAh g−1 at 0.2 C under 60, 40 and 25 °C. In addition, it remains 130 mAh g−1 at 4.0 C, and maintains 91.74% after 500 cycles at 1.0 C under 60 °C. This study provides a simple approach for developing ionic conductor-filled polymer electrolytes in solid-state lithium battery application.