Electro-chemo-mechanical Studies of Perovskite-Structured Mixed Ionic-Electronic Conducting SrSn1-xFexO3-x/2+δ Part I: Defect Chemistry
Electro-chemo-mechanical Studies of Perovskite-Structured Mixed Ionic-Electronic Conducting SrSn1-xFexO3-x/2+δ Part I: Defect Chemistry
复制标题
钙钛矿结构混合离子电子导电 SrSn1-xFexO3-x/2+δ 的电化学机械研究第一部分：缺陷化学
DOI：
10.1007/s10832-017-0064-3
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发表时间：
2017
影响因子：
1.7
通讯作者：
H.L. Tuller
中科院分区：
文献类型：
--
作者：
C.S. Kim;S.R. Bishop;N.H. Perry;H.L. Tuller
在700-1000 °C温度范围内，用热重法研究了SrSn_（1-x）Fe_xO_（3-x/2+δ）（SSF）系统的氧非化学计量和缺陷化学，并与相应的混合离子-电子导电钛酸盐SrTi_（1-x）Fe_xO_（3-x/2+δ）（STF）系统进行了比较。选择交替的B位点主体阳离子Sn来复制和扩展STF研究，因为与钛酸盐中导带的3d性质相比，Sn具有与其5s导带相关的不同能带结构和更高的电子迁移率。虽然稍微移动较大尺寸的Sn，缺陷平衡-包括氧空位浓度-被发现在很大程度上是由Fe的氧化态为主，因此只有在有限的方式不同于那些在STF。计算了SrSn0.65Fe0.35O2.825+δ（SSF 35）的主要热力学参数，包括还原焓（4.137 ± 0.175 eV）、高温电子带隙（1.755 ± 0.015 eV）和阴离子Frenkel焓（0.350 ± 0.350 eV）.这些意见的影响，在固体氧化物燃料电池的阴极行为进行了简要讨论。
Oxygen nonstoichiometry and the defect chemistry of the SrSn1-xFexO3-x/2+δ(SSF) system were examined by means of thermogravimetry as a function of oxygen partial pressure in the temperature range of 700–1000 °C and compared against the corresponding mixed ionic-electronic conducting titanate, SrTi1-xFexO3-x/2+δ(STF) system. The alternate B site host cation, Sn, was selected to replicate and extend the STF studies, given its distinct band structure and higher electron mobility associated with its 5s derived conduction band as compared to the 3d nature of the conduction band in the titanate. Though shifted slightly by the larger size of Sn, the defect equilibria – including the oxygen vacancy concentration – were found to be largely dominated by Fe oxidation state, and thus differed only in a limited way from those in STF. Key thermodynamic parameters for SrSn0.65Fe0.35O2.825+δ(SSF35) were derived including the reduction enthalpy (4.137 ± 0.175 eV), the high temperature electronic band gap (1.755 ± 0.015 eV) and the anion Frenkel enthalpy (0.350 ± 0.350 eV). The implications these observations have for cathode behavior in solid oxide fuel cells are briefly discussed.