Practical application of aqueous Zn‐ion batteries (AZIBs) is significantly limited by poor reversibility of the Zn anode. This is because of 1) dendrite growth, and 2) water‐induced parasitic reactions including hydrogen evolution, during cycling. Here for the first time an elegantly simple method is reported that introduces ethylene diamine tetraacetic acid tetrasodium salt (Na4EDTA) to a ZnSO4 electrolyte. This is shown to concomitantly suppress dendritic Zn deposition and H2 evolution. Findings confirm that EDTA anions are adsorbed on the Zn surface and dominate active sites for H2 generation and inhibit water electrolysis. Additionally, adsorbed EDTA promotes desolvation of Zn(H2O)62+ by removing H2O molecules from the solvation sheath of Zn2+. Side reactions and dendrite growth are therefore suppressed by using the additive. A high Zn reversibility with Coulombic efficiency (CE) of 99.5% and long lifespan of 2500 cycles at 5 mAh cm−2, 2 mAh cm−2 is demonstrated. Additionally, the highly reversible Zn electrode significantly boosts overall performance of VO2//Zn full‐cells. These findings are expected to be of immediate benefit to a range of researchers in using dual‐function additives to suppress Zn dendrite and parasitic reactions for electrochemistry and energy storage applications.

Defects have been found to enhance the electrocatalytic performance of NiFe-LDH for oxygen evolution reaction (OER). Nevertheless,their specific configuration and the role played in regulating the surface reconstruction of electrocatalysts remain ambiguous.H erein, cationic vacancy defects are generated via aprotic-solvent-solvation-induced leaking of metal cations from NiFe-LDH nanosheets.D FT calculation and in situ Raman spectroscopic observation both reveal that the as-generated cationic vacancy defects tend to exist as V M (M = Ni/Fe);under increasing applied voltage,they tend to assume the configuration V MOH ,a nd eventually transform into V MOH-H whichisthe most active yet most difficult to form thermodynamically.M eanwhile,w ith increasing voltage the surface crystalline Ni(OH) x in the NiFe-LDH is gradually converted into disordered status;u nder sufficiently high voltage when oxygen bubbles start to evolve,l ocal NiOOH species become appearing,w hich is the residual product from the formation of vacancy V MOH-H .T hus,w ed emonstrate that the cationic defects evolve along with increasing applied voltage (V M ! V MOH ! V MOH-H ), and reveal the essential motif for the surface restructuration process of NiFe-LDH (crystalline Ni(OH) x ! disordered Ni(OH) x ! NiOOH). Our work provides insight into defect-induced surface restructuration behaviors of NiFe-LDH as at ypical precatalyst for efficient OER electrocatalysis.

large-scale energy-storage systems. [2] Aqueous zinc-based batteries with high safety and low cost provide a new opportunity for energy storage on a large scale. [3] Among the series of zinc-based batteries, the rechargeable zinc-iodine (Zn-I 2 ) battery is promising owing to abundant reserves of iodine in seawater (55 µg L −1 ), [4] high specific capacity (211 mAh g iodine −1), [5] and high discharge potential plateau (1.38 V vs Zn/Zn 2+ ). [6] Besides, the liquid-phase conversion mechanism of I − /I 2 in cathode endows a Zn-I 2 system with excellent rate capability. [7] However, the state-of-the-art Zn-I 2 batteries are still far from satisfactory due to the challenges of intermediates dissolution as well as Zn-anode corrosion. [4a] In aqueous electrolytes, Zn-I 2 batteries present a reversible I − /I 2 redox reaction, in which polyiodide species work as the intermediate state. [7] However, highly soluble polyiodide intermediates cause the serious shuttle effect, leading to irreversible loss of active mass. Even worse, the direct reaction between shuttling polyiodide and Zn anodes will further aggravate serious Zn corrosion and consumption, leading to the low Coulombic efficiency (CE), and limited durability of Zn-I 2 batteries. Therefore, inhibiting the shuttle effect of polyiodide is of great importance to stabilize the I 2 cathode and alleviate the Zn corrosion toward high-cyclability Zn-I 2 batteries. AqueousZn-iodine (Zn-I 2 ) batteries have been regarded as a promising energy-storage system owing to their high energy/power density, safety, and cost-effectiveness. However, the polyiodide shuttling results in serious active mass loss and Zn corrosion, which limits the cycling life of Zn-I 2 batteries. Inspired by the chromogenic reaction between starch and iodine, a structure confinement strategy is proposed to suppress polyiodide shuttling in Zn-I 2 batteries by hiring starch, due to its unique double-helix structure. In situ Raman spectroscopy demonstrates an I 5 − -dominated I − /I 2 conversion mechanism when using starch. The I 5 − presents a much stronger bonding with starch than I 3 − , inhibiting the polyiodide shuttling in Zn-I 2 batteries, which is confirmed by in situ ultraviolet-visible spectra. Consequently, a highly reversible Zn-I 2 battery with high Coulombic efficiency (≈100% at 0.2 A g −1 ) and ultralong cycling stability (>50 000 cycles) is realized. Simultaneously, the Zn corrosion triggered by polyiodide is effectively inhibited owing to the desirable shuttling-suppression by the starch, as evidenced by X-ray photoelectron spectroscopy analysis. This work provides a new understanding of the failure mechanism of Zn-I 2 batteries and proposes a cheap but effective strategy to realize high-cyclability Zn-I 2 batteries.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202201716.