Sulfhydryl and Sulfonic Acid Bifunctional Group Achieving (101) Crystal Preferential Reversible Zn ²⁺ Electrodeposition Without Dendrite and Nucleation Overpotential

Disordered electrodeposition of Zn²⁺ resulted in serious dendrite and hydrogen evolution reactions, greatly decreasing the energy efficiency and durability of aqueous zinc ion batteries (AZIBs). Herein, sodium 2-mercaptoethanesulfonate (MSN) is proposed as a new additive to achieve induced directional electrodeposition of Zn²⁺ on the Zn (101) crystal surface to form a dense uniform Zn metal layer via the cooperative effect of sulfhydryl and sulfonic acid groups. Different from the reported additives, MSN molecules promote the rapid formation of the Zn²⁺ adsorption layer, which greatly accelerates its directed migration rate and orderly nucleation process, achieving eliminated zinc dendrites and nucleation overpotential, far superior to the reported additives. The MSN-introduced Zn||Zn symmetric battery displays amazing durability and is stably cycled for more than 3500 h at 2 mA cm^-2 @ 2 mAh cm^-2, and over 1 000 h even under harsh conditions (5 mA cm^-2 @ 5 mAh cm^-2). Furthermore, the Zn||δ-MnO₂ coin battery offers a high capacity of 201.5 mAh g^-1 and a low recession rate of 1% during 800 cycles at 1 A g^-1, far higher than that of the blank sample (121.3 mAh g^-1, 56.1%), respectively, fully demonstrating the extraordinary advantages and contributions of the new MSN molecules.