The Organic Ligand Etching Method for Constructing In Situ Terraced Protective Layer Toward Stable Aqueous Zn Anode

Abstract

The stability of aqueous Zn‐ion batteries (AZIBs) is highly dependent on the reversibility of stripping/plating Zn anode. In this work, an organic ligand etching method is proposed to develop a series of in situ multifunctional protective layers on Zn anode. Particularly, the 0.02 m [Fe(CN) 6]3− etching solutions can spontaneously etch the Zn anode, creating an in situ protective layer with unique terraced structure, which blocks the direct contact between the electrode and electrolyte and increases the area for Zn2+ ions deposition. Interestingly, all elements in the organic ligands (i.e., C, N, Zn, and Fe) exhibit strong zincophilic, significantly promoting zinc deposition kinetics and enhancing 3D nucleation behavior to inhibit zinc dendrite growth. As a result, the etched Zn anode can provide as high a Coulombic efficiency of 99.6% over 1000 cycles and sustain over 400 h long‐term stability at a high current density of 10 mA cm−2. As general validation, the small amount of metal cations additives (e.g., Ni2+, Mn2+, and Cu2+) can accelerate the synthesis of artificial interface layers with 3D structures and also regulate zinc deposition behavior. This work provides a new idea from the perspective of etching solution selection for surface modification of Zn metal anode.

Open-framework aluminum hexacyanoferrate as a cathode material for high voltage aqueous zinc-ion batteries: effect of Al3+ cations on three-phase transition of AlFe(CN)6

“…4,5 Rechargeable aqueous metal-ion batteries (RAMB) are considered to be promising large-scale electrochemical energy storage devices. 6 At present, according to the metal ions shuttled in the electrochemical reaction, RAMB can be divided into monovalent (Li + , Na + , and K + ) and multivalent (Zn 2+ , Mg 2+ , and Al 3+ ) ion batteries, 7–15 but most of them exhibit a low energy density due to the low operating voltage. Among them, aqueous zinc-ion batteries (ZIBs) with a mild neutral pH (or slightly acidic) electrolyte and high operating voltage hold particular promise for grid-scale energy storage.…”

Electrolyte Modulation of Biological Chelation Additives toward a Dendrite-Free Zn Metal Anode

“…1−3 However, the drastic dendrite growth and parasitic side reactions are the main challenges that hinder the application prospects of Zn anodes. 4−6 To stabilize the Zn anode, many strategies have been proposed, including designing 3D electrode structures, 7,8 constructing artificial protective layers, 9,10 and optimizing the electrolyte formula. 11,12 As such, the incorporation of electrolyte additives has been emerged as a facile and efficacious strategy to stabilize the Zn anode.…”

“…To stabilize the Zn anode, many strategies have been proposed, including designing 3D electrode structures, , constructing artificial protective layers, , and optimizing the electrolyte formula. , As such, the incorporation of electrolyte additives has been emerged as a facile and efficacious strategy to stabilize the Zn anode. Generally, additives can optimize the properties of the anode–electrolyte interface, thereby hindering the undesirable dendrites and side reactions. − For instance, Wang et al introduced dimethyl sulfoxide (DMSO) into ZnCl 2 –H 2 O to regulate the solvation structure of the hydrated Zn 2+ interface and suppress water reduction and Zn dendrite growth .…”

“…The cycling performance of full cells in various electrolytes is shown in Figure f. At the current density of 1 A g –1 , the Zn||α-MnO 2 full cells using ZnSO 4 electrolytes experienced a drastic capacity attenuation behavior, and the capacity retention is only 5% after 300 cycles due to the drastic short circuit . In sharp contrast, the Zn||α-MnO 2 full cells with the Gly/Asp-containing electrolyte delivered enhanced capacity retention after 300 cycles, further suggesting the positive effect of additives on the cycling stability of the full cells.…”