Preparation of gel polymer electrolyte with high lithium ion transference number using GO as filler and application in lithium battery

High lithium ion transference number (tLi+) is one of the requirements of polymer electrolytes for utilization in lithium secondary batteries. Herein, graphene oxide (GO) is used as a filler to fabricate the homogeneous gel polymer electrolyte (GPE) for pursuing high tLi+. The effect of GO on the whole properties of gel polymer electrolytes including conductivity, lithium ion transference number, electrochemical window, electrochemical stability, and cycling performance are explored. Impressively, the GPE containing 0.3 wt% of GO (labeled as GPE-0.3%) demonstrates a high lithium ion transference number of 0.79 and improved electrochemical stability. The LFP/Li battery with GPE-0.3% as the separator shows excellent electrochemical cycle stability and Coulomb efficiency at 25 °C. The discharge specific capacity retention rate of this battery is 94.4% after 100 cycles at 0.2C. All these features make the gel polymer electrolyte useful as a separator of lithium metal batteries for high-performance lithium ion conductors, which exhibits high safety.