In Situ Construction of a Hydrophobic Honeycomb-like Structured ZnMoO Coating Applied for Enhancing Zinc Anode Performance.

Aqueous zinc-ion batteries (AZIBs) suffer from sharp cycling deterioration due to serious interfacial side reactions and corrosion problems on the zinc anode. Herein, an efficacious approach to construct hydrophobic ZnMoO coatings on Zn (denoted as Zn@ZMO) is proposed to mitigate direct contact between the zinc anode and electrolyte and enhance its cycle life. The hydrophobic ZnMoO layer (contact angle = 128°) with a honeycomb-like structure is prepared by an in situ liquid phase deposition method. The as-prepared ZnMoO coating exhibits persistent corrosion protection for Zn through 30 days of immersion in a 2 M ZnSO electrolyte, indicating excellent stability of the ZnMoO layer and ensuring its available application in AZIBs. Unique microchannels in this kind of honeycomb-like structured coating favor Zn ion diffusion and ease of ion transport, especially at high current cycling. Its robust surface exclusion can effectively counter other side reactions induced by water, simultaneously. As a result, the Zn@ZMO symmetrical cell shows a remarkable cycle lifespan exceeding 2700 h at 1 mA cm/1 mA h cm, surpassing that of the bare zinc cell by more than 100 folds. At a current density of 5 A g, the Zn@ZMO//VO cell can still achieve a specific capacity of 167.0 mA h g after 500 cycles with a capacity retention rate of 88%, which demonstrates its long-term cycling stability.