Lotus Effect Inspired Hydrophobic Strategy for Stable Zn Metal Anodes

Abstract

Zn-ion batteries (ZIBs) have long suffered from the unstable Zn metal anode, which faces numerous challenges concerning dendrite growth, corrosion, and hydrogen evolution reaction. The absence of H₂ O adsorption control techniques has become a bottleneck for the further development of ZIBs. Using the stearic acid (SA)-modified Cu@Zn (SA-Cu@Zn) anode as an example, this work illustrates how the lotus effect controls the H₂ O adsorption energy on the Zn metal anode. In situ integrated Cu nanorods arrays and hydrophobic long-chain alkyl groups are constructed, which provide zincophilic ordered channels and hydrophobic property. Consequently, the SA-Cu@Zn anode exhibits long-term cycling stability over 2000 h and high average Coulombic efficiency (CE) of 99.83% at 1 mA cm^-2 for 1 mAh cm^-2 , which improves the electrochemical performance of the Zn||V₂ O₅ full cell. Density functional theory (DFT) calculations combined with water contact angle (CA) measurements demonstrate that the SA-Cu@Zn exhibits larger water CA and weaker H₂ O adsorption than Zn. Moreover, the presence of Cu ensures the selective adsorption of Zn on the SA-Cu@Zn anode, well explaining how the excellent reversibility is achieved. This work demonstrates the effectiveness of the lotus effect on controllable H₂ O adsorption and Zn deposition mechanism, offering a universal strategy for achieving stable ZIB anodes.