Metal-organic framework modified PEO-based solid electrolyte for high-performance all-solid-state lithium metal batteries

All-solid-state lithium metal batteries (ASSLMBs) are expected to provide a next-generation solution for energy storage. However, intrinsic low ionic conductivity of PEO-based electrolyte causes inferior capacity seriously hinders their widespread commercial application. Here, a new kind of solid electrolyte is explored by incorporation of PEO with metal–organic framework ZIF-67 to enhance the ionic conductivity to 1 × 10-4 S cm−1 at room temperature. Lewis acid-base interaction that forms between Co element and TFSI- promotes the dissociation of lithium salt and enhances Li+ transport. Moreover, NH bonds of ZIF-67 combine with the lone pair of electrons of O on the PEO segment to form hydrogen bonds (NH…O), reducing the strong interaction between Li+ and PEO. The cathode with 6 mg cm−2 of LiFePO4 loading delivers a high capacity of 129.7 mAhg-1 at 0.1C. Furthermore, the assembled batteries delivered a capacity of 147 mAhg-1 at room temperature after 300 cycles.