Engineering an Ultrathin and Hydrophobic Composite Zinc Anode with 24 μm Thickness for High-Performance Zn Batteries

The Zn metal anode is subject to uncontrolled dendrites and parasitic reactions, which often require a big thickness of Zn foil, resulting in excess capacity and extremely low utilization. Here, an ultrathin Zn composite anode (24 mu m) is developed with a protective hydrophobic layer (covalent (C2F4)(n) chains and F-doped carbonized ingredient) constructed on Cu foil (denoted as (C2F4)(n)-C@Cu) as a host by one-step pyrolytic evaporation deposition. The repulsion of (C2F4)(n) to Zn2+ makes the (C2F4)(n)-C@Cu interface possess enhanced adsorption ability, driving more charge transfer under the layer. With its good hydrophobicity, this layer prevents H2O from damaging the plated Zn. Combined with the semi-ionic-state fluorine as zincophilic site, the host guides uniform and dense Zn deposition for making ultrathin Zn anode. As a result, the (C2F4)(n)-C@Cu electrode exhibits high average CE of 99.6% over 3000 cycles at 2 mA cm(-2). Benchmarked against the commercial 20 mu m-Zn foil, the (C2F4)(n)-C@Cu@Zn anode achieves enhanced stability (1200 h at 1 mA cm(-2)), only 100 h for the 20 mu m-Zn foil. When paired with V2O5 cathode, the Zn composite anode makes the full cell deliver 88% retention for 2500 cycles.

Automated summary

An ultrathin Zn composite anode with a protective hydrophobic layer is developed on Cu foil, which prevents uncontrolled dendrites and parasitic reactions, leading to higher utilization and stability. The composite anode exhibits an average CE of 99.6% over 3000 cycles and achieves enhanced stability compared to commercial Zn foil.