A gel polymer electrolyte obtained from cellulose acetate/polyvinylidene fluoride composite electrospun membrane for safe lithium metal batteries with high-rate capability

Abstract

Li metal battery is a promising next-generation power storage devices, but faces the serious safety issues caused by the uncontrolled Li dendrite growth and leakage of the flammable organic electrolyte. Herein, a low-cost CA/PVDF (cellulose acetate/polyvinylidene fluoride) composite membrane is prepared via electrospinning technology for safe lithium metal batteries . This membrane (45 μm) exhibits the high porosity (76.9 %) and excellent thermally stability (>180 °C) preventing the short circuit during abuse. The CA/PVDF-based gel polymer electrolyte (GPE), fabricated with CA/PVDF electrospun membrane swelled by carbonate-based organic liquid electrolyte, delivers the ionic conductivity of 1.82 mS cm −1 and Li + transfer number of 0.506, which achieve uniform Li + ion electrodeposition and inhibit the formation of lithium dendrites . As the results, the symmetrical cell Li/CA/PVDF-based GPE/Li exhibits the impressive reversible Li stripping/plating behavior over 300 h at 1 mA cm −2 with the capacity of 1 mA h cm −2 . Furthermore, the assembled LiFePO 4 /GPE/Li battery exhibits the capacity of 101.2 mA h g −1 at 5C with the capacity retention of 94.6 % after 400 cycles, which exceeds that of traditional liquid electrolytes. This research provides a low-cost gel polymer electrolyte via the electrospinning technique for rechargeable lithium batteries with good electrochemical performance and high security.