Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities

Youkun Tao, Sune Dalgaard Ebbesen, Mogens Bjerg Mogensen

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Abstract

In this work the durability of solid oxide cells for co-electrolysis of steam and carbon dioxide (45 % H2O + 45 % CO2 + 10 % H2) at high current densities was investigated. The tested cells are Ni-YSZ electrode supported, with a YSZ electrolyte and either a LSM-YSZ or LSCF-CGO oxygen electrode. A current density of -1.5 and -2.0 A/cm2 was applied to the cell and the gas conversion was 45 % and 60 %, respectively. The cells were operated for a period of up to 700 hours. The electrochemical analysis revealed significant performance degradation for the ohmic process, oxygen ion interfacial transfer process and the reaction process at the Ni-YSZ triple-phase boundaries. The performance degradation is mainly ascribed to the microstructural changes in the Ni-YSZ electrode close to the YSZ electrolyte, including percolation loss of Ni and the contact loss of Ni and YSZ electrolyte. The type of the oxygen electrode showed an influence to the ohmic degradation: the better performing oxygen electrode corresponded to a lower Rs increase. However, the oxygen electrode itself was found to be relative stable both with respect to the electrochemical performance and microstructure.
Original languageEnglish
Title of host publicationProceedings of 11th European SOFC and SOE Forum 2014 : Chapter 12 - Session B06. Durability and lifetime prediction
PublisherEuropean Fuel Cell Forum
Publication date2014
Pages55-65
ISBN (Electronic)978-3-905592-16-0
Publication statusPublished - 2014
EventEuropean fuel cell 2014 - 11th European SOFC and SOE Forum 2014 - Lucerne, Switzerland
Duration: 1 Jul 20144 Jul 2014

Conference

ConferenceEuropean fuel cell 2014 - 11th European SOFC and SOE Forum 2014
CountrySwitzerland
CityLucerne
Period01/07/201404/07/2014

Cite this

Tao, Y., Ebbesen, S. D., & Mogensen, M. B. (2014). Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities. In Proceedings of 11th European SOFC and SOE Forum 2014: Chapter 12 - Session B06. Durability and lifetime prediction (pp. 55-65). European Fuel Cell Forum.