(519e) Improving the Efficiency of High Temperature Electrolysis of Carbon Dioxide in an SOC

Authors: 
Rothman, R. H., University of Sheffield
Call, A. V., University of Sheffield
Holmes, T., Perlemax
Butterworth, T., DIFFER
Desai, P., Perlemax
Zimmerman, W. B., University of Sheffield
Solid Oxide Cells (SOCs) are a leading technology for future clean power generation and chemicals production, whether operated in fuel cell (SOFC) or electrolysis (SOEC) mode, due to their high efficiencies, fuel flexibility and long projected lifetimes. Excess renewable energy produced during off-peak times can be utilised to cheaply reduce a variety of fuels, including carbon dioxide, which can then be further reacted to produce a myriad of hydrocarbon related products. Reported electrical efficiencies of SOECs are around 50% and can be increased to 80% when used in combination with recycled heat from other high temperature systems. At present, over 80% of the cost of electrolysing carbon dioxide is due to the electrical input necessary to drive an SOEC. Recent advances in cell materials and compositions have improved performance, however activation and concentration polarisation need to be addressed to advance the field further.

Here we focus on the development of a bespoke rig which allows for the simultaneous use of non-thermal plasma (NTPs), oscillating gas flow via a Desai-Zimmerman fluidic oscillator, and an SOC to create a highly efficient energy conversion device to facilitate the reduction of carbon dioxide to carbon monoxide. An analysis of the role of NTPs in improving the kinetics and efficiency of reactions, such as dissociation of carbon dioxide to form adsorbed oxygen ions in an SOC, thereby decreasing activation polarization is presented. Performance improvements using a rapidly oscillating gas flow provided by a Desai-Zimmerman fluidic oscillator to minimises concentration polarisation resistance by disrupting boundary layer formation and increasing the overall efficiency are also discussed. The intersection of these three technologies provide a path for a paradigm shift in the ability to convert waste carbon dioxde into high value feedstocks using renewable energy.