High-temperature Electrochemistry has a long history backdated to the discovery of alkali metals in 1807 when Sir Humphry Davy firstly isolated potassium and sodium by electrolysis of molten hydroxides. His student, Michael Faraday, then established Faraday’s laws of electrolysis in 1834 based on high-temperature electrochemical systems. Such a topic soon fulfilled great commercial success in Aluminum extraction via the Hall-Heroult cell in 1886, which is now shining in massive production of metallic Al with the annual yields as high as several hundred million tons. Electrochemistry in high-temperature media offers enhanced reaction kinetics and unique interfacial mechanisms, provoking high-flux and efficient materials preparation/processing, energy storage/conversion, carbon capture/utilization and resource recycling. The classic topic on active metal extraction has hence become a new research hotspot on energy, environmental and resource sustainability that is exactly the central focus of Journal of Energy Chemistry. Deep and comprehensive insights into the interfacial phenomena and service behaviors of the high-temperature electrochemical electrolyzers/batteries/fuel cells are of prime importance, which is the emphasis of the proposed special issue.