AC Impedance Study of the La 0.8 Sr 0.2 MnO 3/YSZ Electrode

Authors

Shizhong Wang
Yi Zhang Yahong Jiang
Jingwang Yan
Wenzhao Li

Abstract

Electrochemical reaction of oxygen on the La 0.8 Sr 0.2 MnO 3/YSZ electrode has been investigated in detail with AC impedance. The results demonstrated that the rate determining step(rds) of the reaction varies with the temperature, oxygen partial pressure and overpotential applied. At open circuit potential, the rds is the dissociative adsorption of oxygen on the LSM surface. A large number of electron holes are generated at high anodic overpotentials, while oxygen vacancies are formed at high cathodic overpotentials. The formation of the electron holes results in the electronic conduction of the YSZ electrolyte and the extension of the electrochemical active area. While the formation of oxygen vacancies leads to the ionic conduction in the LSM electrode and the extension of the electrochemical active area over the LSM electrode surface. The extension of active area and the increase of the conductivity induce some special phenomena reflected in AC impedance spectra, such as the decrease of both the electrode resistance and the ohmic drop, the increase of the double layer capacitance, and the appearance of the low frequency inductive arc at low temperature. The rds of the reaction at low temperature and high overpotentials is the charge transfer step, while at high temperature the rds of the reaction at high anodic and cathodic overpotential are the charge transfer step and the diffusion of oxygen over LSM surface respectively.

DOI Link

https://doi.org/10.61558/2993-074X.2698

Publication Date

1998-08-28

Online Available Date

1998-08-28

Revised Date

1998-08-28

Received Date

1998-08-28

Recommended Citation

Shizhong Wang, Yi Zhang Yahong Jiang, Jingwang Yan, Wenzhao Li. AC Impedance Study of the La 0.8 Sr 0.2 MnO 3/YSZ Electrode[J]. Journal of Electrochemistry, 1998 , 4(3): Article 4.
DOI: 10.61558/2993-074X.2698
Available at: https://jelectrochem.xmu.edu.cn/journal/vol4/iss3/4

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