Parallel zinc deposition enabled by diethylene triaminepentaacetic acid induced interfacial complex for dendrite-free zinc metal anode

Given the high safety, cost-effectiveness, and volumetric capacity, aqueous zinc-ion batteries (ZIBs) constitute a promising energy system, but the severe side reactions and dendrite growth at the anode/electrolyte interface limited ZIBs from large-scale utilization. Here, we proposed a facile strategy to stabilize the anode/electrolyte interface and enhance the reversibility of the zinc plating/stripping via additive engineering. A trace amount of the diethylene triaminepentaacetic acid (DTPA, 3 mM) was employed as an additive, which spontaneously adsorbed onto the Zn anode, and in-situ formed a complex interlayer. This interlayer effectively shielded the water molecules, leading to a superior anti-corrosion property, facilitating the desolvation and diffusion of Zn2+, and inducing the Zn (002) oriented deposition. As a result, outstanding durability was achieved at ultrahigh current density (3000 cycles at 100 mA·cm−2) and relatively high depth of discharge (140 h at 5 mA·cm−2, 85% DOD) in the Zn||Zn symmetric cell. Superior cyclability was also observed in the coin cell (1000 cycles at 5 A·g−1) and pouch cell (500 cycles at 1 A·g−1) with an NH4V4O10 cathode. Furthermore, the formation of complex molecule clusters was elucidated via in-situ Raman and the "bowl" morphologies are firstly visualized by SEM and AFM. These morphologies enable the rapid trapping of Zn2+oriented Zn deposition in the hollow area. We believe this work provides a novel strategy for long-term ZIB designs and offers new insights into the mechanisms for regulating zinc-oriented-deposition behavior at the molecular scale.