Study of Activation Effect of Anodic Current on La0.6Sr0.4Co0.2Fe0.8O3−δ Air Electrode in Solid Oxide Electrolyzer Cell
Study of Activation Effect of Anodic Current on La0.6Sr0.4Co0.2Fe0.8O3−δ Air Electrode in Solid Oxide Electrolyzer Cell
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DOI：
10.1016/j.electacta.2016.05.058
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发表时间：
2016-08
影响因子：
6.6
通讯作者：
Zehua Pan;Qinglin Liu;Lan Zhang;Xiongwen Zhang;S. Chan
中科院分区：
文献类型：
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作者：
Zehua Pan;Qinglin Liu;Lan Zhang;Xiongwen Zhang;S. Chan
本文报道了阳极电流极化La0.6Sr0.4Co0.2Fe0.8O3−δ(LSCF)空气电极的电化学性能演变。利用平衡电位下的电化学阻抗谱对钇稳定氧化锆（YSZ）电解质的三电极半电池进行了研究。最初，900℃烧结的LSCF电极在800℃下测试的极化电阻（RP）为0.25 Ω cm2。在阳极电流密度为0.2 A cm−2的测试前20小时内，rpp随时间的平方根线性增加，表明Sr表面偏析。第一阶段后，testsrp稳定在0.68 Ω cm2。在增加电流密度至0.5 A cm - 2的情况下，继续测试表明，rdp从0.68下降到0.46 Ω cm2，在更高的1 A cm - 2的偏置下再次下降到0.39 Ω cm2。此外，在不同电流下进行129h的短期试验，同样表明，在较高的阳极电流下，rdp降低，在较低的阳极电流下，rdp升高。然而，通过比较测试前后的值，rpp没有明显的下降。基于上述结果，作者推测阳极电流的应用可能通过抑制和减轻Sr表面偏析来稳定和激活LSCF电极的性能。
Electrochemical performance evolution of La0.6Sr0.4Co0.2Fe0.8O3−δ(LSCF) air electrode polarized with anodic current is reported in this paper. The study was conducted on three-electrode half-cells with Yttria stabilized zirconia (YSZ) electrolyte using electrochemical impedance spectroscopy under equilibrium potential. Initially, the polarization resistance (RP) tested at 800 °C of the LSCF electrode sintered at 900 °C is 0.25 Ω cm2. During the first 20 hours of testing with anodic current density of 0.2 A cm−2,RPincreased with a linear dependence on the square root of time, suggesting Sr surface segregation. After the first phase of testsRPstabilized at 0.68 Ω cm2. Continued testing at increased current density to 0.5 A cm−2showed thatRPdecreased from 0.68 to 0.46 Ω cm2, and again to 0.39 Ω cm2at even higher bias of 1 A cm−2. Moreover, short-term tests for 129 h under various currents again showed thatRPdecreased upon higher anodic current while increased upon lower anodic current. However, no obvious degradation onRPwas shown by comparing the value before and after the test. Based on above results, the authors speculate that the application of anodic current may be able to stabilize and activate the performance of LSCF electrode through suppressing and mitigating Sr surface segregation.