Effects of Microalloying Elements (Mg, Ag, Al, Zn, and Sn) on Dendrite Growth and Stability in Li Metal Anodes

In recent years, research on Li metal batteries (LMBs) has surged, with Li alloy materials garnering extensive attention due to their significant commercial prospects. Despite the progress, the precise mechanisms by which various alloying elements suppress Li dendrite growth remain inadequately understood. Herein, microalloyed Li₄₀M@Cu (M = Mg, Ag, Al, Zn, and Sn) composite anodes were successfully prepared by a melting-rolling method. This research conducted a thorough investigation into the effects and mechanisms of these microalloys in influencing Li dendrite growth and stability. Comparative analyses of cycle stability and Li plating/stripping behaviors across different electrodes reveal that microalloying not only suppresses dendrite growth but also substantially enhances the lifespan of LMBs. Notably, Li-Mg and Li-Zn alloys outperform their Li-Ag, Li-Al, and Li-Sn counterparts, attributed to superior Li⁺ diffusion coefficients, reduced solid electrolyte interphase impedances, increased exchange current densities, more stable delithiation morphologies, and improved wettability. These findings significantly advance the understanding of dendrite growth in Li alloys and provide robust theoretical insights for designing and developing advanced multicomponent Li alloy materials in LMBs.