High-Temperature CO2 Electrolysis in Solid Oxide Electrolysis Cells: Developments, Challenges, and Prospects.

High-temperature CO2 electrolysis in solid-oxide electrolysis cells (SOECs) could greatly assist in the reduction of CO2 emissions by electrochemically converting CO2 to valuable fuels through effective electrothermal activation of the stable CO bond. If powered by renewable energy resources, it could also provide an advanced energy-storage method for their intermittent output. Compared to low-temperature electrochemical CO2 reduction, CO2 electrolysis in SOECs at high temperature exhibits higher current density and energy efficiency and has thus attracted much recent attention. The history of its development and its fundamental mechanisms, cathode materials, oxygen-ion-conducting electrolyte materials, and anode materials are highlighted. Electrode, electrolyte, and electrode-electrolyte interface degradation issues are comprehensively summarized. Fuel-assisted SOECs with low-cost fuels applied to the anode to decrease the overpotential and electricity consumption are introduced. Furthermore, the challenges and prospects for future research into high-temperature CO2 electrolysis in SOECs are included.