Ionic conduction studies in P(VDF-HFP)-LiAsF6-(PC + DEC)-fumed SiO2 composite gel polymer electrolyte system

In the present work, thin polymer electrolyte films of P(VDF-HFP) copolymer containing LiAsF6 salt dissolved in PC and DEC and fumed SiO2 submicron particles as dispersed phase prepared by solution casting technique are characterized by ac impedance measurements in the temperature range 303 K-373 K. Maximum ionic conductivity for P(VDF-HFP)-(PC + DEC)-LiAsF6-SiO2 fumed composite gel polymer electrolyte is found to be of the order of 10(-3) S/cm at room temperature. XRD patterns show the increased amorphicity in the electrolytes. The degree of crystallinity is decreased from 30% in pure polymer to 17.7% in composite gel polymer electrolyte. Scanning electron micrographs show uniform dispersion of SiO2 particles and suggest that SiO2 supports formation of porous microstructures and increases the retaining capability of liquid electrolyte in the polymer gel network. FTIR spectral analyses confirm the polymer/salt/filler interaction. (C) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.