Oxide Ion Conductivity of Double Doped Lanthanum Gallate Perovskite Type Oxide

Doping transition metal cation is known to enhance the electronic conduction of solid electrolytes, however, the ionic conduction can also be improved by those dopants. In this investigation, the oxide ion conductivity of LaGaO(3) based oxide doped with transition metal cations such as Fe, Co, Ni, Mn, and Cu for the Ga site was studied. It was found that doping Co or Fe is effective for enhancing the oxide ion conductivity. The improved oxide ion conductivity may be induced by the improved mobility of oxide ion. Among examined transition metal cations, cobalt is the most adequate cation as a dopant for the Ga site of LSGM. Considering the conductivity and the transport number, the optimized composition is found to be La(0.8)Sr(0.2)Ga(0.8)Mg(0.115)Co(0.085)O(3). In this work, application of Co(2+) doped LSGM as the electrolyte of internally reformed fuel cells was also investigated. Improvement in oxide ion conductivity is effective for enhancing the power generation characteristics.