Ultra-High Temperature Molten Oxide Electrochemistry.

Recently, the ultra-high temperature electrochemistry (UTE, about >1000 °C) has emerged, which represents an exploration to extend the temperature limit of human technology in electrochemical engineering. UTE has far-reaching impact on revolutionary low-carbon metal extraction and the in situ production of oxygen for deep-space exploration. It is hence of urgency to systematically summarize the development of UTE. In this Review, the basic concepts of UTE and the physicochemical properties of molten oxides are analyzed. The principles in the design of inert anodes for the oxygen evolution reaction in molten oxides are discussed, which forms a solid basis for the in situ production of oxygen from simulated lunar regolith by UTE. Furthermore, liquid metal cathodes for revolutionary titanium extraction and ironmaking/steelmaking are highlighted. With emphasis on the key challenges and perspectives, the Review can provide valuable inspiration for the rapid advancement of UTE.