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.

Automated summary

Aqueous zinc-ion batteries (ZIBs) are a promising option for large-scale energy storage applications due to their low cost, eco-friendliness, and high safety. However, they currently face challenges such as poor cycling stability caused by dendrite growth, corrosion, and hydrogen evolution at the electrolyte/anode interface. In this study, humic acid (HA), a natural soil ingredient, is applied to the zinc surface to stabilize the anode/electrolyte interface. Theoretical calculations and electrochemical analyses show that HA improves the Zn deposition kinetics, suppresses corrosion and hydrogen evolution, and enhances the overall performance of ZIBs. This research provides valuable insights for engineering electrolyte/electrode interfaces and suggests the potential of leveraging natural materials and mechanisms for more sustainable batteries.