Preparation and performances of poly (ethylene oxide)-Li6PS5Cl composite polymer electrolyte for all-solid-state lithium batteries

Composite polymer electrolytes (CPEs), which are made up of sulfide solid electrolyte Li6PS5Cl dispersed in solid polymer electrolytes (SPEs) based on the poly (ethylene oxide) (PEO), has been prepared by adopting solution casting method. The results show that the addition of appropriate amount of Li6PS5Cl can enhance lithium-ion conductivity and interfacial stability of solid polymer electrolyte, which can play an active role in the electrochemical properties of the improving all-solid-state LiFePO4/Li batteries. Especially, the PEO-1 wt% Li6PS5Cl exhibits a high lithium-ion conductivity of 8.84 × 10−4 S/cm at 80 ℃ and 7.58 × 10−5 S/cm at 30 ℃. Compared with the SPE, the PEO-1 wt% Li6PS5Cl has smaller interfacial impedance and more stable interface with lithium metal. Therefore, all-solid-state LiFePO4/Li batteries assembled by the PEO-1 wt% Li6PS5Cl represent higher coulomb efficiency, and better cycle stability with high initial discharge capacity of 155.43 mAh/g, 134.95 mAh/g at current rates of 0.2C, 0.5C at 60 ℃, respectively.