Cross-linked Electrospun Gel Polymer Electrolytes for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) benefit from an effective electrolyte system design in both terms of their safety and energy storage capability. Herein, a series of precursor membranes with high porosity were produced using electrospinning technology by mixing PVDF and triblock copolymer (PS-PEO-PS), resulting in a porous structure with good interconnections, which facilitates the absorbency of a large amount of electrolyte and further increases the ionic conductivity of gel polymer electrolytes (GPEs). It has been demonstrated that post-cross-linking of the precursor membranes increases the rigidity of the nanofibers, which allows the polymer film to be dimensionally stable up to 260 °C while maintaining superior electrochemical properties. The obtained cross-linked GPEs (CGPEs) showed high ionic conductivity up to 4.53×10⁻³ S·cm⁻¹. With the CGPE-25, the assembled Li/LiFePO₄ half cells exhibited good rate capability and maintained a capacity of 99.4% and a coulombic efficiency of 99.3% at 0.1 C. These results suggest that the combination of electrospinning technique and post-cross-linking is an effective method to construct polymer electrolytes with high thermal stability and steadily decent electrochemical performance, particularly useful for Lithium-ion battery applications that require high-temperature usage.