A Robust Dual-Polymer@Inorganic Networks Composite Polymer Electrolyte Toward Ultra-Long-Life and High-Voltage Li/Li-Rich Metal Battery

Composite polymer electrolytes (CSEs) that simultaneously possess superior electrochemical performances with robust mechanical properties are highly desired to the application of high-energy lithium metal batteries. Herein, a novel dual-polymer@inorganic network CSE (DNSE@IN) through a sequential nonhydrolytic sol-gel reaction of tetraethoxysilane (TEOS) and the semi-interpenetration of poly(vinylidene fluoride-co-hexafluoropropene)-hexafluoropropylene (P(VDF-HFP)) with poly(ionic liquid) (PIL) is proposed. DNSE@IN, which has a robust dual-polymer@inorganic networks, not only has high ionic conductivity (0.53 mS cm −1 at 20 °C), but also exhibits an outstanding Young's modulus of 723.2 MPa. As a result, the DNSE@IN based Li/LiFePO 4 and Li/Li 1.17 Ni 0.27 Co 0.05 Mn 0.52 O 2 (Li-rich) cells exhibit remarkable cycling stability from room temperature (RT) to 100 °C. As-assembled Li/Li-rich battery shows superior cyclability of 194.3 mAh g −1 after 70 cycles at 4.3 V under RT. Additionally, the scale-up high-voltage Li/Li-rich pouch cells exhibit excellent cyclability (nearly 100% capacity retention after 93 cycles) and superior flexibility, safety at RT for potential practical applications. As such, the work of decoupling ionic conductivity and mechanical properties opens a novel route to develop novel CSEs for the construction of high-energy lithium metal batteries.