Electrospun Composite Gel Polymer Electrolytes with High Thermal Conductivity toward Wide Temperature Lithium Metal Batteries

Abstract

Herein, the thermally conductive composite polymer membranes (CPMs) with silica-coated silver nanowires (AgNWs@SiO2) and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) are first fabricated by an electrospinning technique. Various composite gel polymer electrolytes (CGPEs) are investigated with different weight percentages of AgNWs@SiO2 with respect to PVDF-HFP in the presence of liquid electrolytes. The CPMs display high thermal conductivity and thermal stability, good mechanical strength, and high electrolyte uptake. The thermal conduction property of CPMs was analyzed by a bidirectional asymmetric heat transfer model. Moreover, the CGPEs with the electrospun CPM as the matrix and AgNWs@SiO2 as fillers (es-CGPEs) possess the high ionic conductivity and excellent electrochemical performance compared to the Celgard separator system. The Li/es-CGPEs/LiFePO4 cell shows an enlarged excellent cycling life and better rate performance at 25 and 60 °C, in comparison to the one without AgNWs@SiO2 fillers. Interestingly, the Li/es-CGPEs/LiFePO4 cell in the presence of 5 wt % of AgNWs@SiO2 still delivers an excellent rate capability at 0 °C. The es-CGPE with AgNWs@SiO2 would be a promising candidate as the electrolyte material toward wide temperature lithium metal batteries.