Para-Toluene Sulfonamide as an electrolyte additive for dendrite-free Zn metal cells

Abstract

The aqueous Zinc-ion cells have drawn tremendous attention in the electrochemical energy storage market because of their merits of high safety, environmentally friendly and low cost. However, the high activity of aqueous electrolytes leads to the formation of by-products and the growth of unfavorable dendrites, which seriously reduces the cycling stability of the cell. Herein, an electrolyte additive, Para-Toluene Sulfonamide (PTSA) is introduced to regulate uniform Zn deposition and to suppress side reactions. Due to its own electronegativity, PTSA can guarantee a uniform Zn deposition and form a uniform solid electrode/electrolyte interface (SEI). The symmetric cell of Zn‖Zn with PTSA additive can cycle stability more than 3000 h at 2 mA cm−2. Even increase the current to 15 mA cm−2, the cell still can cycle more than 500 h. The low-cost, promising electrolyte additives discovered in this work provide a new method for high-energy secondary Zn metal cells.