In this study, oxide materials La_1−xCa_xScO_3−α (x = 0.03, 0.05 and 0.10) were synthesized by the citric-nitrate combustion method. Single-phase solid solutions were obtained in the case of calcium content x = 0.03 and 0.05, whereas a calcium-enriched impurity phase was found at x = 0.10. Water uptake and release were studied by means of thermogravimetric analysis, thermodesorption spectroscopy and dilatometry. It was shown that lower calcium content in the main phase leads to a decrease in the water uptake. Conductivity was measured by four-probe direct current (DC) and two-probe ascension current (AC) methods at different temperatures, pO₂ and pH₂O. The effects of phase composition, microstructure and defect structure on electrical conductivity, as well as correlation between conductivity and water uptake experiments, were discussed. The contribution of ionic conductivity of La_1−xCa_xScO_3−α rises with decreasing temperature and increasing humidity. The domination of proton conductivity at temperatures below 500 °C under oxidizing and reducing atmospheres is exhibited. Water uptake and release as well as transport properties of La_1−xCa_xScO_3−α are compared with the properties of similar proton electrolytes, La_1−xSr_xScO_3−α, and the possible reasons for their differences were discussed.

The work studies chemical stability and thermal compatibility of composite electrodes in contact with proton electrolyte based on calcium zirconate. Composite of electrolytes of CaZr_0.95Sc_0.05O_3–δ and CaZr_0.9Y_0.1O_3–δ with Fe, Ni, Cu, and Pd metals and also with the perovskite oxide of SrTi_0.8Fe_0.2O_3–δ are considered. Temperature dependences of resistance of porous electrodes made of these materials are studied.