Assessment of structurally stable cubic Bi12TiO20 as intermediate temperature solid oxide fuels electrolyte

Colloid processing and subsequent pressure filtration were used to prepare 14.3 mol% TiO2 doped Bi2O3 (Bi12TiO20, 14BTO) as solid oxide fuel cell electrolyte. Materials characterization and electrical behaviors of 14BTO samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and two-point probe DC conductivity. A pure 14BTO with a cubic sillenite single phase was prepared at the sintering process of 850 °C with a high relative sintered density of 96.82%. In situ and batch-type long-term conductivity measurements at 600 °C were carried out to verify the possible reason of degradation. Additional reduction–oxidation tests under CH4 atmosphere by thermogravimetric analysis (TGA) revealed possible application temperature of 14BTO electrolytes below 700 °C.