Ionic Conduction and Application of Ba1.03Ce0.8Tm0.2O3−α Ceramic

Ba_1.03Ce_0.8Tm_0.2O_3?α ceramic with orthorhombic perovskite structure was prepared by conventional solid‐state reaction. The conductivity and ionic transport number of Ba_1.03Ce_0.8Tm_0.2O_3?α were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 500–900°C in wet hydrogen and wet air. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen‐air fuel cell was constructed, and the cell performance was examined at 500–900°C. The results indicate that the specimen is a pure ionic conductor with the ionic transport number of 1 at 500–900°C in wet hydrogen. In wet air, the specimen is a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers are 0.071–0.018, and the oxide ionic transport numbers are 0.273–0.365. The conductivities of Ba_1.03Ce_0.8Tm_0.2O_3?α under wet hydrogen, wet air or fuel cell atmosphere are higher than those of Ba_1.03Ce_0.8RE_0.2O_3?α (RE?Y, Eu, Ho) reported previously by us. The fuel cell can work stably. At 900°C, the maximum power output density is 122.7 mW·cm^?2, which is higher than that of our previous cell using Ba_1.03Ce_0.8RE_0.2O_3?α (RE?Y, Eu, Ho) as electrolyte.