A Room Temperature Alloying Strategy to Enable Commercial Metal Foil for Efficient Li/Na Storage and Deposition

Abstract Metal substrate has significant functions in regulating Li/Na deposit behaviors to inhibit dendrite growth, but most alloyable metal foils such as Al, Sn, Zn suffer from severe low energy efficiency upon charge/discharge. Herein, it is demonstrated a novel room-temperature alloying strategy to enable commercial Sn foil as hybrid anode/current collector in Li and Na metal batteries. By introducing tiny Hg into Sn foil, the spontaneous alloying reaction afford uniform distribution of Hg into the entire Sn foil, forming a hexagonal Sn0.9Hg0.1 amalgam phase. Compared to pristine metallic β-Sn, this binary alloy electrode allows highly reversible Li/Na diffusion within the foil, and thus considerably promotes the efficiency of Li/Na utilization as well as the inhibition of dendric morphologies. Prototype cell configurations composed of both LiFePO4|Sn-Hg and NaxFe[Fe(CN)6]|Sn-Hg demonstrate stable lifespan over 1000 cycles with high Coulombic efficiency. In addition, this facile room-temperature alloying process has been successfully extended to Zn foil, indicating it can be a universal strategy to design versatile polynary alloy electrodes for alkali metal batteries.