In Situ Construction of a Hydrophobic Honeycomb-like Structured ZnMoO 4 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 4 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 4 layer (contact angle = 128°) with a honeycomb-like structure is prepared by an in situ liquid phase deposition method. The as-prepared ZnMoO 4 coating exhibits persistent corrosion protection for Zn through 30 days of immersion in a 2 M ZnSO 4 electrolyte, indicating excellent stability of the ZnMoO 4 layer and ensuring its available application in AZIBs. Unique microchannels in this kind of honeycomb-like structured coating favor Zn 2+ 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 -2 /1 mA h cm -2 , surpassing that of the bare zinc cell by more than 100 folds. At a current density of 5 A g -1 , the Zn@ZMO//V 2 O 5 cell can still achieve a specific capacity of 167.0 mA h g -1 after 500 cycles with a capacity retention rate of 88%, which demonstrates its long-term cycling stability.