Influencing Factors and Challenges on the Wettability of Electrode in Molten Salt

Molten salts play an important role in the electrolysis of solid metal compounds, especially oxides and sulfides, and have an impressive storage capacity and power, so they are now the electrolyte for many new types of rechargeable batteries. Unfortunately, due to the high viscosity and high surface tension of molten salt, the unsatisfactory wettability of electrode and molten salt restricts the development of molten salt electrochemistry. In the past half century, the research on interface phenomena has been devoted to establishing more accurate models for measuring surface tension and wetting angle, developing more scientific wetting angle measurement techniques, and exploring the influencing factors of wettability. Different from water solution interface, molten salt experiment is in high temperature and pressure environment, so it is difficult to test the wetting angle, and there are few researches on the interface phenomenon of molten salt. In this paper, on the basis of existing models and experimental data, the factors and mechanisms that lead to the difference of wettability between melt and solid matrix in molten salt systems are analyzed in detail. Finally, we put forward the prospects and suggestions for the study of the wettability of melt to solid substrate in molten salt. The research status of electrode wettability in molten salt is reviewed systematically, and the measuring method and mechanism of high-temperature interface wettability are introduced briefly.To propose a priority scheme to improve the wettability of electrodes, the factors affecting the wettability of electrodes in molten salt were summarized and discussed in detail.We put forward the prospects and suggestions for the study of the wettability of electrodes in molten salt.