skip to main content

SciTech ConnectSciTech Connect

Title: High-efficiency intermediate temperature solid oxide electrolyzer cells for the conversion of carbon dioxide to fuels

Electrochemical reduction of carbon dioxide in the intermediate temperature region was investigated by utilizing a reversible solid oxide electrolysis cell (SOEC). The current potential (i-V) curve exhibited a nonlinear characteristic at low current density. Differentiation of i-V curves revealed that the cell area specific resistance (ASR) was current-dependent and had its maximum in electrolysis mode and minimum in fuel cell mode. Impedance measurements were performed under different current densities and gas compositions, and the results were analyzed by calculating the distribution of relaxation times. The ASR variation resulted from the difference in electrochemical reactions occurring on the Ni-YSZ electrode, i.e., Ni-YSZ is a better electrode for CO oxidation than for CO2 reduction. Coke formation on Ni-YSZ played a crucial role in affecting its electrolysis performance in the intermediate temperature region. The ASR apex was associated with a decrease in cell temperature during electrolysis due to the endothermic nature of CO2 reduction reaction. It was postulated that such a decrease in temperature and rise in CO concentration led to coke formation. As a consequence, higher temperature (>700 degrees C), higher CO2 concentration (>50%), and the presence of hydrogen or steam are recommended for efficient CO2 reduction in solid oxide electrochemical cells.more » (C) 2013 Elsevier B.V. All rights reserved« less
; ; ; ; ;
Publication Date:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Power Sources, 252:79-84
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
Country of Publication:
United States
High temperature electrolysis; CO2 reduction; Distribution of relaxation times analysis; Carbon deposition