The commercialization pace of aqueous zinc batteries
(AZBs) is
seriously limited due to the uncontrolled dendrite growth and severe
corrosion reaction of the zinc anode. Herein, a universal and extendable
saturated fatty acid-zinc interfacial layer strategy for modulating
the interfacial redox process of zinc toward ultrastable Zn metal
anodes is proposed. The in situ complexing of saturated fatty acid-zinc
interphases could construct an extremely thin zinc compound layer
with continuously constructed zincophilic sites which kinetically
regulates Zn nucleation and deposition behaviors. Furthermore, the
multifunctional interfacial layer with internal hydrophobic carbon
chains as a protective layer is efficient to exclude active water
molecules from the surface and efficiently inhibit the surface corrosion
of zinc. Consequently, the modified anode shows a long cycle life
of over 4000 h at 5 mA cm–2. In addition, the assembled
Zn||V2O5 full cells based on modified zinc anodes
have excellent rate performance and long cycle stability.
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 µm) 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 20µm‐Zn foil, the (C2F4)n‐C@Cu@Zn anode achieves enhanced stability (1200 h at 1 mA cm−2), only 100 h for the 20µm‐Zn foil. When paired with V2O5 cathode, the Zn composite anode makes the full cell deliver 88% retention for 2500 cycles.
Aqueous zinc batteries usher in a renaissance due to their intrinsic security and cost effectiveness, bespeaking vast application foreground for large‐scale energy storage system. However, uncontrolled dendrite growth along with hydrogen evolution severely restricts its reversibility and stability for practical application. Herein, the surface of Zn metal is reconstructed with metallic particles (In, Sn, In0.2Sn0.8) to diminish surface defects and regulate Zn deposition behavior. The alloyed In–Sn greatly activates the Zn surface for lower Zn adsorption energy barrier to expedite plating kinetics and confine Zn aggregation. Dense and uniform deposition of Zn on the reconstructed surface significantly prevents the Zn substrate from dendrites growth for catastrophic damage. Meanwhile, alloy layer embodies high hydrogen evolution overpotential, ensuring high plating and stripping efficiency for Zn anode. Consequently, In0.2Sn0.8 reconstructed surface realizes long‐term lifespan up to 1800 h with low polarization (12 mV) at the condition of 1 mA cm−2 and 1 mAh cm−2. When paired with sodium vanadate (NVO) cathode, the full cell steady operates for a high‐capacity retention of 94.0% after 5000 cycles at 5 A g−1. This study provides new insights into the surface‐defects dependent Zn deposition process and offers a guide for constructing stable surface for dendrite‐free Zn growth.
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