Ionic conductivity and fuel cell properties of apatite-type lanthanum silicates doped with Mg and containing excess oxide ions
Ionic conductivity and fuel cell properties of apatite-type lanthanum silicates doped with Mg and containing excess oxide ions
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DOI：
10.1016/j.ssi.2008.07.022
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发表时间：
2008-11-30
影响因子：
3.2
通讯作者：
Tanase, Shigeo
中科院分区：
文献类型：
--
作者：
Yoshioka, Hideki;Nojiri, Yoshihiro;Tanase, Shigeo
研究了硅酸镧基磷灰石离子导电性的提高，重点优化了La的组成和Mg的掺杂水平。在磷灰石硅酸盐中，La(10)Si(5.8)Mg(0.2)O(26.8)和La(9.8)Si(5.7)Mg(0.3)O(26.4)的离子电导率最高，在800℃时分别为8.8和7.4×10(-2)S cm(-1)，活化能很低(0.42-0.43 eV)。在900℃以下，它们的电导率高于氧化钇稳定的氧化锆(YSZ)，甚至在550℃以下可与掺锶和掺镁的没食子酸镧(LSGM)相媲美。以La(9.8)Si(5.7)Mg(0.3)O(26.4)为电解液的Ni-CeO金属陶瓷为阳极，掺锶钴酸镧为阴极的固体氧化物燃料电池，与以往使用铂电极的数据相比，其发电性能有了显著的提高。粉末X射线衍射谱的Rietveld分析表明，掺镁使导电沟道的瓶颈三角形尺寸明显增大。(C)2008爱思唯尔B.V.保留所有权利。
Enhancement of the ionic conductivity of lanthanum silicate-based apatites is examined with emphasis on optimizing the La composition and the Mg doping level at the same time. La(10)Si(5.8)Mg(0.2)O(26.8) and La(9.8)Si(5.7)Mg(0.3)O(26.4) show the highest level of the ionic conductivities among apatite silicates, 8.8 and 7.4 x 10(-2) S cm(-1) at 800 degrees C, respectively, with a very low level of activation energy (0.42-0.43 eV). Their conductivities are higher than yttria stabilized zirconia (YSZ) below 900 degrees C and even comparable to Sr and Mg doped lanthanum gallate (LSGM) below 550 degrees C. A solid oxide fuel cell using La(9.8)Si(5.7)Mg(0.3)O(26.4) as an electrolyte with Ni-ceria cermet anode and Sr doped lanthanum cobaltite cathode exhibits a remarkable improvement in power generation compared to previous data using Pt electrodes. Structural investigation by the Rietveld analysis on the powder X-ray diffraction pattern shows significant enlargement of the bottleneck triangle sizes of the conduction channel with the Mg doping. (C) 2008 Elsevier B.V. All rights reserved.