AgNbO3 dispersed Ag2SO4 composite for potentiometric SO2 gas sensor application

Composite electrolytes of Ag2SO4 is prepared by dispersing fine particles, average particle size <40 microns (350 mesh), of ferroelectric AgNbO3 in varying weight fraction. Enhancement in the conductivity is observed in β-phase of host system. The effect of dispersion on the conductivity, activation energy and transition temperature is studied as a function of weight % of the dispersoid in the host. Two distinct conduction mechanisms, viz. conduction through electrolyte bulk in parallel with conduction along the inter-grain interaction layer (Rb‖ ‖R∞) and perpendicular to the interface (Rb⊥) could be resolved in the frequency range of 5 Hz to 13 MHz at temperatures below 300 °C. The interface interaction is found to be nucleophilic increasing the concentration of Ag+ vacancies at the interface. Potentiometric SO2 gas sensors are tested with this composite electrolyte as an auxiliary phase.