High-temperature electrolysis of CO2–enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells

Si Won Kim, Yonggyun Bae, Kyung Joong Yoon, Jong Ho Lee, Jong Heun Lee, Jongsup Hong

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

To mitigate CO2 emissions, its reduction by high-temperature electrolysis using solid oxide cells is extensively investigated, for which excessive steam supply is assumed. However, such condition may degrade its feasibility due to massive energy required for generating hot steam, implying the needs for lowering steam demand. In this study, high-temperature electrolysis of CO2-enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells is considered to satisfy such needs. The effect of internal and external steam supply on its electrochemical performance and gas productivity is elucidated. It is shown that the steam produced in-situ inside the fuel-electrode by a reverse water gas shift reaction may decrease significantly the electrochemical resistance of dry CO2-fed operations, attributed to self-sustaining positive thermo-electrochemical reaction loop. This mechanism is conspicuous at low current density, whereas it is no longer effective at high current density in which total reactant concentrations for electrolysis is critical. To overcome such limitations, a small amount of external steam supply to the CO2-enriched feed stream may be needed, but this lowers the CO2 conversion and CO/H2 selectivity. Based on these results, it is discussed that there can be minimum steam supply sufficient for guaranteeing both low electrochemical resistance and high gas productivity.

Original languageEnglish
Pages (from-to)369-374
Number of pages6
JournalJournal of Power Sources
Volume378
DOIs
Publication statusPublished - 2018 Feb 28

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Keywords

  • Area specific resistance
  • CO conversion
  • CO reduction
  • Electrolysis
  • Solid oxide cell
  • Syngas selectivity

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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