Electrical properties of La 2S 3-doped calcium sulfide solid electrolyte

Abstract

In order to consider the application of La 2S 3-doped calcium sulfide to a solid electrolyte for metal sulfide systems, its electrical properties have been investigated, based on a galvanic cell technique and conductivity measurements at various temperatures and sulfur pressures. The following cell was employed; Cu,Cu 2S |CaS (La 2S 3)| FeS, Fe. The values of the electromotive force obtained in this cell were roughly consistent with the theoretical ones. Based on conductivity measurements under various sulfur pressures at 700–900°C, the electrical conduction of La 2S 3-doped calcium sulfide was found to be ionic at sulfur pressures higher than 10 −6 atm and n-type semiconducting at lower sulfur pressures. The apparent activation energy obtained for the ionic conduction was 19.02 kcal/mol, which was reasonable for the ionic conduction through migration of a Ca 2+ ion.