Plastic crystalline-semi crystalline polymer composite electrolyte based on non-woven poly(vinylidenefluoride-co-hexafluoropropylene) porous membranes for lithium ion batteries

Abstract

The advantageous properties of both solid soft matter electrolytes and polymer gel electrolytes (PGEs) are combined to develop a electrospun polymer composite electrolyte (PCE) for lithium ion batteries, based on addition of butanedinitrile (BDN, the plastic crystal) to poly(vinylidenefluoride-co-hexafluoropropylene) {P(VdF-co-HFP)} (semi crystalline polymer). Polymer composite electrolytes are prepared by activating the fibrous membrane with 1M LiPF6 in EC/DEC. The electrochemical characterization shows that the addition of BDN significantly improves the ionic conductivity of composite electrolytes even at lower temperatures due to the active role played by BDN in ion conduction. Also the compatibility of the polymer composite electrolyte with lithium electrode improves by incorporation of BDN. Galvanostatic cycling test demonstrates the suitability of these polymer composite electrolytes for lithium ion batteries in both Li/PCE/LiFePO4 (half cell) and LTO/PCE/LiFePO4 (full cell) configurations. The addition of BDN improves the charge discharge performance and cycling stability of the polymer composite electrolytes.