Lesnichyova Alyona, Stroeva Anna, Belyakov Semyon, Farlenkov Andrey, Shevyrev Nikita, Plekhanov Maksim, Khromushin Igor, Aksenova Tatyana, Ananyev Maxim, Kuzmin Anton
Laboratory of Electrochemical Material Sciences, Institute of High-Temperature Electrochemistry, Yekaterinburg 620137, Russia.
Institute of New Materials and Technologies, Ural Federal University, Yekaterinburg 620002, Russia.
Materials (Basel). 2019 Jul 10;12(14):2219. doi: 10.3390/ma12142219.
In this study, oxide materials LaCaScO (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, O and HO. 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 LaCaScO 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 LaCaScO are compared with the properties of similar proton electrolytes, LaSrScO, and the possible reasons for their differences were discussed.
在本研究中，采用柠檬酸 - 硝酸盐燃烧法合成了氧化物材料LaCaScO（x = 0.03、0.05和0.10）。当钙含量x = 0.03和0.05时获得了单相固溶体，而在x = 0.10时发现了富钙杂质相。通过热重分析、热脱附光谱和热膨胀法研究了水的吸收和释放。结果表明，主相中较低的钙含量导致水吸收量的减少。在不同温度、O和HO条件下，采用四探针直流（DC）和两探针升流（AC）方法测量了电导率。讨论了相组成、微观结构和缺陷结构对电导率的影响，以及电导率与水吸收实验之间的相关性。LaCaScO的离子电导率贡献随着温度降低和湿度增加而上升。在氧化和还原气氛下，在低于500°C的温度下质子导电占主导地位。将LaCaScO的水吸收和释放以及传输性能与类似质子电解质LaSrScO的性能进行了比较，并讨论了它们差异的可能原因。
