Fuller Chloe A, Blom Douglas A, Vogt Thomas, Evans Ivana Radosavljevic, Evans John S O
Department of Chemistry, Science Site, Durham University, South Road, Durham DH1 3LE, United Kingdom.
Department of Chemical Engineering and NanoCenter, University of South Carolina, Columbia, South Carolina 29208, United States.
J Am Chem Soc. 2022 Jan 12;144(1):615-624. doi: 10.1021/jacs.1c11966. Epub 2021 Dec 30.
Functional oxides showing high ionic conductivity have many important technological applications. We report oxide ion and proton conductivity in a family of perovskite-related compounds of the general formula AOhTdO, where Oh is an octahedrally coordinated metal ion and Td is a tetrahedrally coordinated metal ion. The high tetrahedral content in these ABO compositions relative to that in the perovskite ABO or brownmillerite ABO structures leads to tetrahedra with only three of their four vertices connected in the polyhedral framework, imparting a potential low-energy mechanism for O migration. The low- and high-temperature average and local structures of BaYGaO (2/, = 7.94820(5) Å, = 5.96986(4) Å, = 18.4641(1) Å, and β = 91.2927(5) ° at 22 °C) were determined by Rietveld and neutron pair distribution function (PDF) analysis, and a phase transition to a high-temperature 112/ structure ( = 12.0602(1) Å, = 9.8282(2) Å, = 8.04982(6) Å, and γ = 107.844(3)° at 1000 °C) involving the migration of O ions was identified. Ionic conductivities of BaYGaO and compositions substituted to introduce additional oxide vacancies and interstitials are reported. Most phases show proton conductivity at lower temperatures and oxide ion conductivity at high temperatures, with BaYGaO retaining proton conductivity at high temperatures. BaLaYGaO and BaYGaTiO appear to be dominant oxide ion conductors, with conductivities an order of magnitude higher than that of the parent compound.
具有高离子电导率的功能氧化物有许多重要的技术应用。我们报道了通式为AOhTdO的一类钙钛矿相关化合物中的氧化物离子和质子电导率，其中Oh是八面体配位的金属离子，Td是四面体配位的金属离子。这些ABO组成中相对于钙钛矿ABO或褐锰矿ABO结构的四面体含量较高，导致四面体在多面体框架中只有四个顶点中的三个相连，为氧迁移提供了一种潜在的低能量机制。通过Rietveld和中子对分布函数（PDF）分析确定了BaYGaO（22℃时，a = 7.94820(5) Å，b = 5.96986(4) Å，c = 18.4641(1) Å，β = 91.2927(5)°）的低温和高温平均结构及局部结构，并确定了涉及氧离子迁移的向高温112/结构（1000℃时，a = 12.0602(1) Å，b = 9.8282(2) Å，c = 8.04982(6) Å，γ = 107.844(3)°）的相变。报道了BaYGaO以及引入额外氧化物空位和间隙的替代组成的离子电导率。大多数相在较低温度下显示质子电导率，在高温下显示氧化物离子电导率，而BaYGaO在高温下仍保留质子电导率。BaLaYGaO和BaYGaTiO似乎是主要的氧化物离子导体，其电导率比母体化合物高一个数量级。
