Semi-interpenetrating-network PEO-based polymer electrolytes with fast Li-ion conduction for solid Li-metal batteries

Semi-interpenetrating-network (semi-IPN) PEO-based solid polymer electrolytes (SPEs) are synthesized for the application of Li-metal batteries. Owing to the special semi-IPN structure and synergistic effects of EO segments and PVDF-HFP, the SIN solid electrolytes demonstrate great flexibility, high ionic conductivity of 2.45 × 10−4 S cm−1 at 25 °C, outstanding thermal stability and broad electrochemical window (4.9 V vs. Li+/Li). In addition, SIN owns excellent electrochemical stability with Li-metal with a low over-potential <70 mV after 1400 h Li plating/stripping. Moreover, benefiting from the stable interfacial contact, LiFePO4|SIN|Li cells provide high discharge capacity of 146 mAh g−1 with superior capacity retention of 96.6 % after 500 cycles at 0.1C under room temperature. Hence, the semi-IPN PEO-based SPEs appear to be promising for use in high-performance solid-state Li-metal batteries.