Review of room-temperature liquid metals for advanced metal anodes in rechargeable batteries

Metal anodes with a plating/stripping electrochemical behavior are promising anode materials for rechargeable batteries due to their low electrochemical potential, superior electronic conductivity, good machinability, and high theoretical specific capacity. These metal anodes include Li, Na, K, Mg, Ca, Al, Fe, Zn, Mn, etc. Nevertheless, several issues affect their development and application, such as high chemical reactivity, uneven electrochemical deposition, unstable solid electrolyte interphase (SEI), and large volume change of electrodes during cycling. Recently, room-temperature liquid metals (RLM) such as metallic Ga, Ga-based alloy (GaIn, GaSn, GaZn, GaInSn, GaInSnZn, etc.), metallic Hg, and liquid Na-K alloy have exhibited large potential in addressing the issues of metal anodes and a lot of advances have been reported. Here these advances are summarized and analyzed in detail. Meanwhile, some perspectives and outlooks are put forward. RLM can effectively solve the issues of metal anodes by constructing 3D current collectors, regulating nucleation, designing artificial interface layer, fabricating composite anodes, heat conduction, eliminating already existing dendrites, stress release, etc. This review can promote the development of multifunctional RLM as well as rechargeable metal based batteries.