A review on liquid metals as cathodes for molten salt/oxide electrolysis

Compared with solid metals, liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages, which include strong depolarization effect, strong alloying effect, excellent selective separation, and low operating temperature. In this review, we briefly introduce the properties of the liquid metal cathodes and their selection rules, and then summarize development in liquid metal cathodes for molten salt electrolysis, specifically the extraction of Ti and separation of actinides and rare-earth metals in halide melts. We also review recent attractive progress in the preparation of liquid Ti alloys via molten oxide electrolysis by using liquid metal cathodes. Problems related to high-quality alloy production and large-scale applications are cited, and several research directions to further improve the quality of alloys are also discussed to realize the industrial applications of liquid metal cathodes.