CONDUCTIVITY VARIATIONS IN COMPOSITES OF ALPHA-ZIRCONIUM PHOSPHATE AND FUMED SILICA

Composite proton-conducting solid electrolytes have been formed from alpha-zirconium phosphate (alpha-Zr(HPO4)2.H2O, alpha-ZrP) and high surface area non-porous fumed silica in varying mole ratios. Conductivity variations as a function of temperature and relative humidity have been characterised and compared to that for a similarly prepared delaminated ZrP (no silica). Conductivities increase with relative humidity and E(a) decreases at high silica mole fractions. Conduction is via exposed lamellar surfaces and other microstructural imperfections in the composites.