CO2 to CO electrochemical conversion in molten Li 2CO3 is stable with respect to sulfur contamination

Valery Kaplan, Ellen Wachtel, Igor Lubomirsky

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The conversion of CO2 to CO via the electrolysis of molten Li2CO3 at 900 °C has a number of advantages including close to 100% faradaic and thermodynamic efficiencies, the latter limited by heat loss. Here we report that when the incoming gas contains SO2, sulfur uptake by the melt occurs only in the presence of oxygen and leads to the formation of Li2SO4. The electrolysis of molten Li 2CO3/Li2O containing 2SO4 produces CO, O2 and elemental sulfur. Under these conditions, the decomposition potential of Li2SO 4 is measured to be only 0.15 V, which is much lower than the decomposition potential of Li2CO3 (0.87 V). At sufficiently high cathode current densities (>1 A/cm2), the sulfur reduction current is diffusion limited and a steady state can be reached in which the amount of sulfur entering the melt equals the amount of sulfur leaving the melt. Thus even with SO2-containing sources of CO2, electrochemical conversion of CO2 to CO is able to proceed, but with reduced faradaic efficiency. Our findings suggest that the molten carbonate method for converting CO2 to CO can use flue gas from power stations as an inexpensive and readily available source of CO2.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume161
Issue number1
DOIs
Publication statusPublished - 2014

Fingerprint

Carbon Monoxide
Sulfur
Molten materials
contamination
Contamination
sulfur
electrolysis
Electrolysis
Decomposition
decomposition
thermodynamic efficiency
flue gases
Carbonates
Heat losses
Flue gases
carbonates
Cathodes
Current density
stations
Gases

ASJC Scopus subject areas

  • Electrochemistry
  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Renewable Energy, Sustainability and the Environment
  • Condensed Matter Physics

Cite this

CO2 to CO electrochemical conversion in molten Li 2CO3 is stable with respect to sulfur contamination. / Kaplan, Valery; Wachtel, Ellen; Lubomirsky, Igor.

In: Journal of the Electrochemical Society, Vol. 161, No. 1, 2014.

Research output: Contribution to journalArticle

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