A self-supporting solid electrolyte membrane with fibrous network structure for solid state lithium metal batteries

High ionic conductivity and good interface compatibility have always been two major bottlenecks for solid-state electrolytes. Herein, a composite electrolyte membrane comprising poly (propylene carbonate), PVDF-HFP and Li 6 · 3 La 3 Zr 1 · 4 Ta 0 · 6 O 12 is successfully prepared via electrospinning. With the assistance of succinonitrile, the synthesized solid-state electrolyte exhibits high ionic conductivity (1.32 × 10 −3  S cm −1 at room temperature), oxidation potential up to 4.5 V vs Li/Li + and high Li + transference number (0.81). This desirable performance is attributed to the combination of PPC with good Li + conduction ability and PVDF-HFP with excellent mechanical properties, forming a continuous transport framework within the electrolyte. The introduced active fillers and small molecular additive not only benefit to fast Li + mobility, but also reinforce the stability towards Li metal. Li symmetric cell using the solid-state electrolyte can last for 800 h at a current density of 1.0 mA cm −2 with a low overpotential. The NCM811 cell using the electrolyte membrane shows high initial discharge specific capacity (184.3 mAh g −1 at 1 C) and good capacity retention (80.1% after 300 cycles at 30 °C).