A Self-Supporting Solid Electrolyte Membrane with Fibrous Network Structure for Solid State Lithium Metal Batteries

Abstract

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), wide potential window (up to 5.35 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 cathode matching Li anode 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).

Keywords: composite solid electrolyte, high conductivity, PPC, fibrous network, self-supporting