Arginine Cations Inhibiting Charge Accumulation of Dendrites and Boosting Zn Metal Reversibility in Aqueous Rechargeable Batteries

Aqueous zinc-ion batteries are regarded as one of the new promising rechargeable batteries. However, serious Zn dendrite growth causes short-circuit issues in the batteries. Herein, we report that arginine (Arg), a cationic surfactant electrolyte additive, can inhibit irregular and nonplanar dendrite growth and induce uniform Zn deposition. It shows a long cycle life (515 h) of Zn/Zn cells in the electrolyte containing Arg, which is ∼10 times longer than that of the electrolyte with no additive. The hydrolysis of Arg produces arginine cations (Arg⁺), which will be preferentially adsorbed on Zn dendrites due to the tip charge accumulation effect during the Zn plating process. Arg⁺ increases the overpotential for the nucleation of Zn dendrites and results in uniform Zn deposition. After about 350 cycles, the MnO₂/Zn cell shows 84.59% capacity retention and 99.85% average Coulomb efficiency in the electrolyte with the additive. The low-cost and nontoxic electrolyte additive identified in this work provides a new pathway toward inducing regular Zn deposition morphology.