Electrospun derived polymer-garnet composite quasi solid state electrolyte with low interface resistance for lithium metal batteries

Abstract

Polymer garnet composite electrolyte is a promising stable electrolyte to replace the hazardous/unstable liquid electrolytes in lithium-ion batteries due to their synergistic advantage of solid organic polymer electrolytes and inorganic ceramic electrolytes. Herein, we report polymer blend-based garnet composite quasi solid state electrospun electrolytes for lithium metal batteries. To be specific, Ta doped lithium lanthanum zirconium oxide, Li6·4La3Ta0·6Zr1·4O12 (LLZTO) incorporated with poly (vinyldine fluoride-hexafluro propylene) (PVdF-HFP)/poly butyl methacrylate (PBMA) electrospun membrane as the composite electrolyte, named as Ta-ESM and similarly, LLZTO free electrolyte named as ESM. The inclusion of LLZTO into the polymer matrix enhances the room temperature ionic conductivity from 9.924 × 10−4 (ESM) to 4.858 × 10−3 S cm−1 (Ta-ESM) along with lithium-ion transference number (0.61). Furthermore, polymer garnet composite electrolytes (Ta-ESM) restraint the growth of lithium dendrites, confirmed by the time-dependent impedance method and galvanostatic cycling technique. We have demonstrated the charge-discharge behaviour of lithium-metal battery using LiFePO4 cathode and lithium metal anode using Ta-ESM electrolyte, delivering 178 mA h g−1 at 0.1C and cyclability of 100 cycles. The high electrolyte uptake (582%) and porosity (64.1%) in Ta-ESM help achieve fast ionic migration and thus attain stable cycling.