Oxygen reduction mechanism at porous La1-xSrxCoO3-d cathodes/La0.8Sr0.2Ga0.8Mg0.2O2.8 electrolyte interface for solid oxide fuel cells

被引：116

作者：

Horita, T

Yamaji, K

Sakai, N

Yokokawa, H

Weber, A

Ivers-Tiffée, E

机构：

[1] Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan

[2] Univ Karlsruhe, Inst Werkstoffe Elektrotech, D-76131 Karlsruhe, Germany

来源：

ELECTROCHIMICA ACTA | 2001年 / 46卷 / 12期

关键词：

oxygen reduction; interface reaction; polarization resistance; SOFC; cathode reaction;

D O I：

10.1016/S0013-4686(00)00722-2

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

081704 ;

摘要：

The oxygen reduction mechanism was investigated at the porous La1-xSrxCoO3-d cathode/ La0.8Sr0.2Ga0.8Mg0.2O2.8, electrolyte interface (x=0.2, 0.3, 0.4). The polarization resistance, measured from the impedance spectra, was compared in the samples of La1-xSrxCoO3-d as functions of x, temperatures, and applied DC voltages. The polarization resistance decreased with an increase of x values in La1-xSrxCoO3-d and with the applied cathodic voltage. The polarization resistance of the higher Sr-concentration in La1-xSrxCoO3-d showed the lower dependence on cathodic overpotential. The values of the activation energy of the interface conductivity (inverse of the polarization resistance) were similar for all La1-xSrxCoO3-d samples (127-143 kJ mol(-1)) at zero applied voltage (E = 0 V). However, under cathodic polarization, the activation energy decreased as the applied voltage became more negative, which indicates a change of the reaction mechanism under cathodic polarization. Under cathodic polarization, oxide ion diffusion in the bulk La1-xSrxCoO3-d can be one of the main factors determining the reaction rates. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

引用

页码：1837 / 1845

页数：9

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