A flexible three-dimensional composite nanofiber enhanced quasi-solid electrolyte for high-performance lithium metal batteries

Solid-state lithium-ion batteries have attracted great attention in recent years due to their remarkable safety and high energy density. However, the ionic conductivities of most solid-state electrolytes (SSE) are still not high enough for practical applications. Herein, we report a high-performance quasi-solid-state electrolyte composed of an electrospinning LATP-PVDF-HFP nanofiber matrix and an in situ formed gel. The prepared quasi-solid gel electrolyte shows a 3D porous network with significantly improved ionic conductivity up to 3.394 mS cm(-1). Meanwhile, the quasi-solid-state electrolyte exhibits a wider electrochemical window than the gel electrolyte, due to the synergistic effect between the 3D network fiber and in situ formed gel. The Li vertical bar CGE vertical bar LiFePO4 battery with this quasi-solid gel electrolyte shows good rate capability and cycling stability, and the discharge capacity of the cell is 146.6 mA h g(-1) at 2C. The capacity retention can still reach 97% after 300 cycles at 0.5C. This work provides a promising strategy for designing high-performance lithium metal batteries.