LiFAP-based PVdF–HFP microporous membranes by phase-inversion technique with Li/LiFePO₄ cell

Abstract

Polyvinylidenefluoride–hexafluoropropylene-based (PVdF–HFP-based) gel and composite microporous membranes (GPMs and CPMs) were prepared by phase-inversion technique in the presence 10 wt% of AlO(OH) _n nanoparticles. The prepared membranes were gelled with 0.5-M LiPF₃(CF₂CF₃)₃ (lithium fluoroalkylphosphate, LiFAP) in EC:DEC (1:1 v/v) and subjected to various characterizations; the AC impedance study shows that CPMs exhibit higher conductivity than GPMs. Mechanical stability measurements on these systems reveal that CPMs exhibit Young’s modulus higher than that of bare and GPMs and addition of nanoparticles drastically improves the elongation break was also noted. Transition of the host from α to β phase after the loading of nanosized filler was confirmed by XRD and Raman studies. Physico-chemical properties, like liquid uptake, porosity, surface area, and activation energy, of the membranes were calculated and results are summarized. Cycling performance of Li/CPM/LiFePO₄ coin cell was fabricated and evaluated at C/10 rate and delivered a discharge capacity of 157 and 148 mAh g⁻¹ respectively for first and tenth cycles.