Towards High-Utilization of a Four-Electron Sn Anode Aqueous Battery

Developing high-energy density aqueous batteries is a vital step towards inexpensive and safe energy storage. A major challenge in this approach is achieving high utilization and reversibility with multi-electron metal anodes while operating near the water stability window. Of the main metal anode candidates (Zn, Al, Mg, Fe, Sn, etc.), Sn has recently received increasing attention due to its limited hydrogen evolution activity, dendrite-free plating, and high theoretical capacity for the four-electron Sn(OH)₆^2-/Sn redox couple in alkaline electrolytes (903 mAh g_Sn^-1 or 6,560 Ah L_Sn^-1).

Understanding the reversibility of charge transfer processes that occur in aqueous batteries with metal anodes necessitates probing the solid, liquid, and gaseous phases that evolve during cycling. In this talk, we will discuss a robust toolbox of direct characterization tools developed to investigate the electrochemical behavior of alkaline Sn batteries. We elucidate the asymmetric plating/stripping process that occurs during cycling and investigate changes to the system's behaviour when operated at high Sn utilization to develop high energy density, low-cost aqueous batteries.