Degradation of solid oxide cells during co-electrolysis of H2O and CO2: Carbon deposition under high current densities

Youkun Tao, Sune Dalgaard Ebbesen, Mogens Bjerg Mogensen

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

During co-electrolysis of H2O and CO2 using solid oxide cells (SOCs) the risk of carbon deposition in the Ni-YSZ electrode under high current densities (∼ 2.0 A/cm2) was studied in this work. Five galvanostatic tests were performed at current density between 1.5 and 2.25 A/cm2 and the average conversions of the reactants were no more than 66.8 %. Ni-YSZ electrode delamination and carbon nano-fibers could be observed after test at the Ni-YSZ | YSZ electrolyte interface for two of the cells. Thermodynamic calculation shows that the reactant conversion needed for carbon formation is above 99 %, far above the experimental conversions. The observed carbon formation may be caused by the gas diffusion limitations at high current densities. Carbon nano-fibers were only observed close to the YSZ electrolyte indicating a large overpotential gradient at the TPBs close to the electrolyte. © The Electrochemical Society.
Original languageEnglish
JournalE C S Transactions
Volume50
Issue number49
Pages (from-to)139-151
ISSN1938-5862
DOIs
Publication statusPublished - 2012
EventPacific Rim Meeting on Electrochemical and Solid-State Science: 222nd Meeting of ECS — The Electrochemical Society and 2012 Fall Meeting of The Electrochemical Society of Japan - Hawaii Convention Center and the Hilton Hawaiian Village, Honolulu, United States
Duration: 7 Oct 201212 Oct 2012
http://www.electrochem.org/meetings/biannual/222/222.htm

Conference

ConferencePacific Rim Meeting on Electrochemical and Solid-State Science
LocationHawaii Convention Center and the Hilton Hawaiian Village
Country/TerritoryUnited States
CityHonolulu
Period07/10/201212/10/2012
Internet address

Keywords

  • Carbon
  • Current density
  • Deposition
  • Electrolysis
  • Electrolytes
  • Nanofibers
  • Nickel
  • Carbon dioxide

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