High performance electrospun PVdF‐HFP/SiO₂ nanocomposite membrane electrolyte for Li‐ion capacitors

Electrospun poly[(vinylidene fluoride)‐ co ‐hexafluoropropylene]/silica (PVdF‐HFP/SiO 2 ) nanocomposite polymer membranes (esCPMs) were prepared by incorporating different weight percentages of SiO 2 nanoparticles onto electrospun PVdF‐HFP by electrospinning technique. The surface morphology of electrospun PVdF‐HFP nanocomposite membranes was characterized by scanning electron microscopy. The effect of SiO 2 nanoparticles incorporation onto electrospun PVdF‐HFP polymer membranes (esPMs) has been studied by XRD, DSC, TGA, and tensile analysis. The electrospun PVdF‐HFP/SiO 2 based nanocomposite membrane electrolytes (esCPMEs) were prepared by soaking the corresponding esCPMs into 1 M LiPF 6 in EC:DMC (1:1 vol/vol %). The ionic conductivity of the esCPMEs was studied by AC‐impedance studies and it was found that the incorporation of SiO 2 nanoparticles into PVdF‐HFP membrane has improved the ionic conductivity from 1.320 × 10 −3 S cm −1 to 2.259 × 10 −3 S cm −1 . The electrochemical stability of the esCPME was studied by linear sweep voltammetry studies and it was found to be 2.87 V. Finally, a prototype LiCo 0.2 Mn 1.8 O 4 //C Li‐ion capacitor (LIC) cell was fabricated with esCPME, which delivered a discharge capacitance of 128 F g −1 at the current density of 1 A g −1 and retained 86% of its discharge capacitance even after 10,000 cycles. These results demonstrated that the esCPMEs could be used as promising polymer membrane electrolyte for LICs.