晶内和晶界对Sc掺杂CaHfO3输运性能的影响,Journal of Alloys and Compounds

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晶内和晶界对Sc掺杂CaHfO3输运性能的影响
Journal of Alloys and Compounds ( IF 5.8 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.jallcom.2020.155126
Yushi Ding , Ying Li , Congju Zhang , Wenlong Huang

摘要制备了一种新型CaHf0.9Sc0.1O3-α钙钛矿质子导体，并通过缺陷化学理论和H2/H2O浓差电池系统研究了晶内和晶界对载流子传输性能的影响。CaHf0.9Sc0.1O3-α 表现出正交畸变，CaHf0.9Sc0.1O3-α 的标准摩尔水合焓为-44 kJ/mol。CaHf0.9Sc0.1O3-α 在氧条件下质子、氧空位和空穴传导的迁移活化能分别为 0.81 eV、1.68 eV 和 1.79 eV。CaHf0.9Sc0.1O3-α晶粒中的质子浓度高于晶界，而晶粒中的氧空位浓度低于晶界。质子传导通过 CaHf0.9Sc0。1O3-α 在 Ar 和 500-800 °C 的还原气氛中占主导地位，其中空穴电导率 (σ h · ) 和空穴传输数 ( th · ) 随着氧分压的增加而显着增加。相对输运数结果表明，CaHf0.9Sc0.1O3-α的晶粒内部比晶界更适合阻止空穴输运，晶粒内部可用于提高质子输运数t OH O·。

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Effect of grain interior and grain boundaries on transport properties of Sc-doped CaHfO3

Abstract A novel CaHf0.9Sc0.1O3-α perovskite protonic conductor was prepared and the effects of grain interior and grain boundaries on the carriers’ transport properties were systematically investigated via defect chemistry theory and H2/H2O concentration cell. The CaHf0.9Sc0.1O3-α exhibited an orthorhombic distortion and the standard molar hydration enthalpy of CaHf0.9Sc0.1O3-α was found to be −44 kJ/mol. The migration activation energies for conduction of protons, oxygen vacancies, and holes in CaHf0.9Sc0.1O3-α under oxygen were 0.81 eV, 1.68 eV, and 1.79 eV, respectively. The proton concentration in CaHf0.9Sc0.1O3-α grains was higher than that in the grain boundaries, while in contrast, the oxygen vacancy concentration in grains was lower than that in the grain boundaries. The proton conduction through CaHf0.9Sc0.1O3-α was dominant in Ar as well as reductive atmospheres at 500–800 °C, where the hole conductivity ( σ h · ) and hole transport number ( t h · ) remarkably increased with increasing oxygen partial pressure. The relative transport number results reveal that the grain interior of CaHf0.9Sc0.1O3-α is better suited than grain boundaries to block the hole transport, and grains interior could be used to improve the protons transport number t OH O · .

更新日期：2020-09-01

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