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Halogenated Zn 2+ Solvation Structure for Reversible Zn Metal Batteries.

Authors :
Zhang Q
Ma Y
Lu Y
Ni Y
Lin L
Hao Z
Yan Z
Zhao Q
Chen J
Source :
Journal of the American Chemical Society [J Am Chem Soc] 2022 Oct 12; Vol. 144 (40), pp. 18435-18443. Date of Electronic Publication: 2022 Sep 28.
Publication Year :
2022

Abstract

Rechargeable aqueous Zn metal batteries have become promising candidates for large-scale electrochemical energy storage owing to their high safety and affordable low cost. However, Zn metal anode suffers from dendritic growth and hydrogen evolution reaction (HER), deteriorating the electrochemical performance. Here, we demonstrate that these challenges can be conquered by introducing a halogen ion into the Zn <superscript>2+</superscript> solvation structure. By designing an electrolyte composed of zinc acetate and ammonium halide, the electron-donating anion I <superscript>-</superscript> can coordinate with Zn <superscript>2+</superscript> and transform the traditional Zn(H <subscript>2</subscript> O) <subscript>6</subscript> <superscript>2+</superscript> to ZnI(H <subscript>2</subscript> O) <subscript>5</subscript> <superscript>+</superscript> , in which I <superscript>-</superscript> could transfer electrons into H <subscript>2</subscript> O and thus suppress HER. The dynamic electrostatic shielding layer formed by concomitant NH <subscript>4</subscript> <superscript>+</superscript> can restrict the dendritic growth. As a result, the halogenated electrolyte achieves a high initial coulombic efficiency (CE) of 99.3% in the Zn plating/stripping process and remains at an average of ∼99.8% with uniform Zn deposition. Moreover, Zn-I batteries are constructed by using dissociative I <superscript>-</superscript> as the cathode and carbon felt-polyaniline as the conductive and adsorptive layer, exhibiting an average CE of 98.6% without capacity decay after 300 cycles. This work provides insights into the halogenated Zn <superscript>2+</superscript> solvation structure and offers a general electrolyte design strategy for achieving a highly reversible Zn metal anode and batteries.

Details

Language :
English
ISSN :
1520-5126
Volume :
144
Issue :
40
Database :
MEDLINE
Journal :
Journal of the American Chemical Society
Publication Type :
Academic Journal
Accession number :
36170558
Full Text :
https://doi.org/10.1021/jacs.2c06927