A widely used nonionic surfactant with desired functional groups as aqueous electrolyte additives for stabilizing Zn anode

Aqueous Zn-ion batteries (AZIBs) have emerged as potential candidates for Li-ion batteries due to their intrinsic safety and high capacity. However, metallic Zn anodes encounter dendrite growth and water-induced corrosion, rendering poor stability and severe irreversibility at the electrode/electrolyte interface during cycling. To stabilize the Zn anode, we report a low-cost and effective nonionic surfactant, Tween-20 polymer, as an electrolyte additive for AZIBs. For Tween-20, sequential oxyethylene groups tended to be preferentially adsorbed on the Zn electrode to form a shielding layer for regulating uniform Zn nucleation. Moreover, the hydrophobic hendecyl chains prevented H₂O-induced corrosion on the Zn anode surface. Benefiting from the desired functional groups, when only trace amounts of Tween-20 (0.050 g·L⁻¹) were used, the Zn anode displayed good cycling stability over 2170 h at 10 mA·cm⁻² and a high average Coulombic efficiency of 98.94% over 1000 cycles. The Tween-20 polymer can also be effectively employed in MnO₂/Zn full batteries. Considering their toxicity, price and amount of usage, these surfactant additives provide a promising strategy for realizing the stability and reversibility of high-performance Zn anodes.