A stable and easily sintering BaCeO₃-based proton-conductive electrolyte

Ba(Ce_0.8-xSn_x)Y_0.2O_3-s (x = 0, 0.05, 0.10, 0.15, 0.20, 0.25) powders were prepared by solid state reaction method. The powder samples with Sn element still keep pervoskite-type configuration after boiling in water for 3 h while the BaCe_0.8Y_0.2O_3-s powders apparently decompose into amorphous phases, which indicates the oxides doped with Sn exhibit good chemical stability. Thermal gravity analysis indicates the compounds with Sn possess better chemical stability in CO₂ compared with BaCe_0.8Y_0.2O_3-s. The BaCe_0.7Sn_0.1Y_0.2O_3-s sample displays a conductivity of 0.007 S/cm at 700 °C in wet hydrogen. Although the relative density of BaCe_0.8Y_0.2O_3-s only reaches 88.3% after sintering at 1400 °C, the Ba(Ce_0.8-xSn_x)Y_0.2O_3-s samples exhibit relative densities as high as 96.0%. A fuel cell with BaCe_0.7Sn_0.1Y_0.2O_3-s electrolyte was prepared by a suspension spray combining with in situ sintering method and tested in humid hydrogen. Its output and interface resistance are 470 mW/cm² and 0.13 O cm² at 700 °C, respectively. The short-term performance test also indicates it has good stability as well as desirable compatibility between electrolyte and electrodes. © 2008 Elsevier B.V. All rights reserved.