Grain boundary space charge modulation in BaZr0.8Y0.2-xMxO3-δ with transition metal (M = Ni, Co, Fe, and Zn) co-doping
Grain boundary space charge modulation in BaZr0.8Y0.2-xMxO3-δ with transition metal (M = Ni, Co, Fe, and Zn) co-doping
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DOI：
10.1016/j.ijhydene.2020.07.207
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发表时间：
2020-10-30
影响因子：
7.2
通讯作者：
Babu, K. Suresh
中科院分区：
文献类型：
--
作者：
Aarthi, U.;Babu, K. Suresh
BaZrO_3等质子导电陶瓷电解质的晶界电阻越高，总电导率越低。本文采用水热辅助沉淀法制备了具有不同摩尔浓度(x=0.01、0.03和0.05)的过渡金属(M=Ni、Co、Fe和Zn)的BaZr0.8Y0.2-xMxO3-Delta电解液。X射线衍射仪、拉曼光谱等结构分析表明，样品中存在立方钙钛矿结构的锆酸钡。通过施加直流偏压时晶界电阻的非线性行为证实了空间电荷层的存在。在200摄氏度的还原气氛下进行的MotteSchottky分析表明，添加二次掺杂后，势垒电位从0.24 V降低到0.13 V。掺杂偏析和带电缺陷与掺杂之间的静电相互作用使弹性能最小，从而抑制了空间电荷层。过渡金属掺杂，特别是Ni和Fe，沿晶界偏析，起到平衡带电缺陷的作用。此外，Fe是一种理想的助烧剂，在600℃时具有较高的致密化(~gt；99%)和较高的质子电导率(21.2MSCM(-1))。这些结果表明，过渡金属离子作为共掺杂影响了锆酸钡电解液的空间电荷效应和密度。(C)2020氢能源出版物有限责任公司。爱思唯尔有限公司出版。保留所有权利。
The higher grain boundary resistance of proton-conducting ceramic electrolytes such as BaZrO3 drops the total conductivity. In the present study, BaZr0.8Y0.2-xMxO3-delta electrolyte with various transition metals (M = Ni, Co, Fe, and Zn) with molar concentrations (x = 0.01, 0.03 & 0.05) were prepared by hydrothermal assisted precipitation method. The structural analysis, such as XRD and Raman, revealed the presence of the cubic perovskite phase of barium zirconate. The existence of space charge layer was confirmed by nonlinear behaviour of the grain boundary resistance on applying DC bias. The MotteSchottky analysis performed at 200 degrees C in reducing atmosphere showed a reduction in barrier potential from 0.24 to 0.13 V upon the addition of the secondary dopants. The elastic energy minimization by dopant segregation and electrostatic interaction between the charged defects and dopants suppress the space charge layer. The transition metal dopant, especially Ni and Fe, segregates along the grain boundary and acts as the counterbalance for charged defects. Besides, Fe act as perfect sintering aid which leads to higher densification (>99%) as well as higher protonic conductivity of 21.2 mScm(-1) at 600 degrees C. These results imply that the transition metal ions as co-dopant influence the space charge effect and the density of the barium zirconate electrolyte. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.