High-temperature electrocatalysis and key materials in solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) can convert electricity to chemicals with high efficiency at ~600–900 °C, and have attracted widespread attention in renewable energy conversion and storage. SOECs operate in the inverse mode of solid oxide fuel cells (SOFCs) and therefore inherit most of the advantages of SOFC materials and energy conversion processes. However, the external bias that drives the electrochemical process will strongly change the chemical environments in both in the cathode and anode, therefore necessitating careful reconsideration of key materials and electrocatalysis processes. More importantly, SOECs provide a unique advantage of electrothermal catalysis, especially in converting stable low-carbon alkanes such as methane to ethylene with high selectivity. Here, we review the state-of-the-art of SOEC research progress in electrothermal catalysis and key materials and provide a future perspective.