Preparation and Electrical Property of Ba1.03Ce0.8Ho0.2O3-α Solid Electrolyte

Ba1.03Ce0.8Ho0.2O3-alpha solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition, surface and fracture morphologies of the material were characterized by using XRD and SEM, respectively. Ionic transport number and conductivity of the material were measured by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600-1000 degrees C in dry air, wet air and wet hydrogen, respectively. Ionic conduction was researched and compared with those of BaCe0.8Ho0.2O3-alpha and Ba0.97Ce0.8Ho0.2O3-alpha. The results indicate that Ba1.03Ce0.8Ho0.2O3-alpha is a single-phase perovskite-type orthorhombic system. In the temperature range of 600-1000 degrees C, it is a mixed conductor of oxide ion and electron hole with the oxide ionic transport number of 0.10-0.36 in dry air atmosphere, a mixed conductor of proton, oxide ion and electronic hole with the protonic transport number of 0.11-0.01 and the oxide ionic transport number of 0.34-0.30 in wet air atmosphere, and a pure protonic conductor with the protonic transport number of I in wet hydrogen atmosphere. Ba1.03Ce0.8Ho0.2O3-alpha has the highest conductivities (3.92 x 10(-2) S.cm(-1) in dry air, 3.46 x 10(-2) S.cm(-1) in wet air, 2.10 x 10(-2) S.cm(-1) in wet hydrogen, at 1000 degrees C) among the three materials, and the ionic conduction is superior to that of BaCe0.8Ho0.2O3-alpha. and Ba0.97Ce0.8Ho0.2O3-alpha under the experimental conditions.