An analysis of the electrical conductivity in BaSO4-added Ag2SO4solid electrolyte system

摘要

The compositions (1 −x)Ag2SO4−(x)BaSO4, wherex=0·01 to 0·6, were prepared by slow cooling of the melt. The extent of the solid solubility of Ba2+in Ag2SO4was determined by X-ray powder diffraction and scanning electron microscopy. The bulk conductivity of each sample was obtained using a detailed impedance analysis. The partial substitution of Ba2+results in the enhancement of conductivity in compliance with the classical aliovalent doping theory. A simplistic model based on lattice distortion (expansion) due to partial substitution of Ag+by the bigger Ba2+has been considered to explain enhanced conductivity. Beyond solid-solubility limit (5·27 mole) the BaSO4-dispersed Ag2SO4conductivity follows the usual trend seen in binary systems. An increase in conductivity in this case is discussed in the light of interfacial reactions and surface defect chemistry. The maximum conductivity in 20 mole BaSO4dispersed Ag2SO4is due to percolation thr