Non-Sacrificial Anionic Surfactant with High HOMO Energy Level As a General Descriptor for Zinc Anode

Hydrogen evolution and dendrite growth severely plague the implementation of aqueous zinc-ion batteries. The electrolyte regulation strategy is powerful to alleviate the excrescent reactions of the electrolyte to Zn anode. However, there lacks effective electrolyte approaches for regulating stable and reversible Zn plating/stripping chemistry. Herein, we propose a general principle through evaluating the highest occupied molecular orbital (HOMO) energy level of molecules and employ it as a critical descriptor to select non-sacrificial anionic surfactant electrolyte additives for stabilizing Zn anodes. Benefiting from the high HOMO energy level, the excellent coordination and adsorption effects of the non-sacrificial surfactant additive renders the modulated solvation structure and dynamic molecule-enriched layer on the Zn anode, realizing sustainable regulation effect. The optimized electrolyte reduces water activity, uniforms Zn2+ flux, and stabilizes 3D ion diffusion near the anode/electrolyte interface, leading to the inhibited parasitic reactions and homogenous Zn nucleation and growth. Consequently, a stable and reversible Zn anode is obtained, represented by an ultralong cycling lifespan over 3200 h at 2 mA cm−2/2 mAh cm−2 and high coulombic efficiency of 99.75%. This study provides a general guidance for screening optimal electrolyte additives for high-performance aqueous zinc-ion batteries.