Conductivity modification of proton conducting polymer gel electrolytes with the addition of fumed silica

The addition of nano size fumed silica to non aqueous proton conducting polymer gel electrolytes containing ammonium hexafluorophosphate (NH4PF6) has been found to modify the conductivity and viscosity behavior. Two maxima observed in the conductivity vs. fumed silica plot at very low concentrations have been explained to be due to an increase in free ion concentration with the dissociation of ion aggregates, and the formation of a high conducting interfacial layer between the particles of fumed silica and polymer gel electrolytes respectively. The change in free ion concentration has been monitored by pH measurements whereas change in mobility has been checked from viscosity measurements. The dissociation of ion aggregates with the addition of fumed silica has also been supported by FTIR results. The variation of conductivity and viscosity with time. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.