Gel electrolytes based on poly(vinylidenefluoride-co-hexafluoropropylene)/thermoplastic polyurethane/poly(methyl methacrylate) with in situ SiO2 for polymer lithium batteries

Abstract

Gel polymer electrolyte films based on poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF–HFP), thermoplastic polyurethane (TPU) and poly(methyl methacrylate) (PMMA) with and without in situ SiO₂ fillers are prepared by electrospinning a polymer solution at room temperature. The electrospun PVDF–HFP/TPU/PMMA blending membrane with 2% in situ SiO₂ shows a highest ionic conductivity of 8.5 × 10⁻³ S cm⁻¹ with electrochemical stability up to 5.9 V versus Li⁺/Li at room temperature. In addition, it shows a first charge of 168.5 mA h g⁻¹, which is about 99% of the theoretical capacity of LiFePO₄; the tensile strength of the PVDF–HFP/TPU/PMMA membrane is 10.8 MPa with elongation-at-break at 86.4%. With the outstanding electrochemical and mechanical performance, it is very suitable for application in polymer lithium batteries.