Organic polymeric filler-amorphized poly(ethylene oxide) electrolyte enables all-solid-state lithium-metal batteries operating at 35 °C

The poor ionic conductivity and high working temperatures (normally >60 °C) of poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) greatly limit their applications in all-solid-state batteries. To mitigate these issues, for the first time, we report here an organic polymer filler, hydrolyzed polymaleic anhydride (HPMA) that can greatly suppress the PEO crystallinity, enhance the ionic conductivity of PEO-based SPEs (1.13×10-4 S cm-1 at 35 °C) and support the battery operation at 35 °C. PEO-HPMA SPEs are featured with their high flexibility, incombustibility, wide electrochemical operating window and stability against lithium. The as-derived Li/PEO-HPMA/LiFePO4 all-solid-state batteries show outstanding rate capability, high reversible capacity and long-term stability up to 1250 cycles. Impressively, the soft-packaged Li/PEO-HPMA/LiFePO4 cells show high safety under various extreme conditions such as cutting and perforation. The PEO-HPMA SPEs-based quasi-solid-state lithium-sulfur batteries is also presented. This work demonstrates a facile approach that unlocks the low-temperature application of PEO SPE-based all-solid-state batteries.