Hydrophobic, zincophilic and conductive SEI protective layer stabilizes metallic Zn anode under high current densities

The uncontrollable growth of Zn dendrites and adverse side reactions significantly hinder the application of metallic Zn anodes in aqueous batteries. Herein, nitrogen-doped carbon skeleton/ZnO nanocrystalline are grown in-situ within carbon hollow dodecahedrons (denoted as CZCHD) through the controlled pyrolysis of zeolitic imidazole framework-8 dodecahedrons coated with polydopamine. The solid electrolyte interface layer constructed by CZCHD suppresses hydrogen evolution and corrosion reactions, reduces nucleation barrier, improves Zn deposition kinetics, accelerates desolvation and transport of Zn2+ ions, and regulates Zn deposition behavior. When tested in symmetric cells, CZCHD@Zn anodes afford exceptional plating/stripping stability at 5 mA cm- 2/ 1 mAh cm- 2 (2681 h), 10 mA cm- 2/10 mAh cm- 2 (780 h), and 20 mA cm- 2/20 mAh cm- 2 (240 h). In asymmetric cells, CZCHD@Cu exhibits average Coulombic efficiency of 99.5 % over 500 cycles. Morphological and structural evolution analyses demonstrate the preferential horizontal flaky Zn deposition beneath the CZCHD protective layer, with no Zn dendrites observed on the surface. Furthermore, when coupled with MnVO cathodes, the assembled full cells display stable cycling performance at 2 and 5 A/g. The stable, reversible, efficient, dendrite-free Zn deposition is attributed to the synergistic effects of high hydrophobicity, strong zincophilicity and high electrical conductivity of CZCHD, which is confirmed by contact angle measurements, theoretical calculations based on density functional theory, and electrochemical impedance spectroscopy.