Nature-inspired interfacial engineering for highly stable Zn metal anodes

Aqueous zinc-ion batteries (ZIBs) emerge as a potential candidate for large-scale energy storage applications, due to their low cost, eco-friendliness, and high safety. However, nowadays, ZIBs still suffer from poor cycling sta-bility, owing largely to the severe dendrite growth, corrosion, and hydrogen evolution at the electrolyte/anode interface. Herein, inspired by the biomolecule-assisted cationic transport mechanism in nature, we apply humic acid (HA, a natural ingredient of soil) on the Zn surface for stabilizing the anode/electrolyte interface. Density functional theory calculations indicate that the tuned interactions between Zn2+ and the segments of HA possibly facilitate the desolvation of Zn2+. The theoretical results are supported by the electrochemical analyses, where the HA-induced interfacial layer promotes the reversible Zn deposition kinetics and suppresses the corrosion and hydrogen evolution. The improved electrochemical performance is validated by Zn/MnO2 coin and pouch cells. These findings not only provide insights into engineering electrolyte/electrode interfaces but also suggest that a broader family of materials, structures, and mechanisms in nature can be leveraged for more sustainable batteries.