Water Uptake and Transport Properties of La1−xCaxScO3−α Proton-Conducting Oxides

Materials

Andrey Farlenkov¹  Maxim Ananyev¹  Anna Stroeva²  Alyona Lesnichyova²  Semyon Belyakov²  Anton Kuzmin²  Maksim Plekhanov²  Igor Khromushin³  Tatyana Aksenova³  Nikita Shevyrev⁴ 

[1] Institute of Chemical Engineering, Ural Federal University, Yekaterinburg 620002, Russia;Laboratory of Electrochemical Material Sciences, Institute of High-Temperature Electrochemistry, Yekaterinburg 620137, Russia;Laboratory of Radiation Diffusion, Institute of Nuclear Physics, Almaty 050032, Kazakhstan;Laboratory of Solid State Oxide Fuel Cells, Institute of High-Temperature Electrochemistry, Yekaterinburg 620137, Russia;

关键词: LaScO₃;    defect structure;    water uptake;    proton conductivity and proton mobility;   

DOI  :  10.3390/ma12142219

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown