Affiliation:
1. Key Laboratory of Cluster Science Ministry of Education Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
Abstract
AbstractPseudohalogens are neutral molecules with similar chemical properties to halogens that can be utilized in zinc batteries. For instance, thiocyanogen, (SCN)2, features a fairly positive standard redox potential when coupled with SCN− (0.77 V vs SHE, standard hydrogen electrode) and serves as a feasible cathode to pair zinc anode. However, the severe hydrolysis of (SCN)2 and generation of trithiocyanate ion, (SCN)3−, and parathiocyanogen, (SCN)x, seriously undermine the couple reversibility, leading to a poor electrochemical performance. Herein, by selecting a water‐in‐salt ZnCl2 electrolyte and an oxygen‐enriched carbon electrode, an effective (SCN)2/SCN− electrochemistry is activated. On the one hand, intensive ion coordination decreases free H2O and SCN− contents to suppress detrimental hydrolysis of (SCN)2 and generation of (SCN)3− and (SCN)x. On the other hand, high electronegativity of oxygen‐containing functional groups facilitates the adsorption of in situ generated (SCN)2 and reduces side reactions. As a result, Zn─(SCN)2 battery can be charged–discharged for 500 cycles and exhibits high capacities (479 mAh g−1 based on the mass of (SCN)2 or 1.73 mAh cm−2 based on device area) and remarkable energy densities (644 Wh kg−1 or 2.216 mWh cm−2). This first reported Zn─(SCN)2 battery pioneers the zinc─pseudohalogen battery and raises it to a higher level among aqueous batteries.
Funder
National Natural Science Foundation of China
Subject
Electrochemistry,Condensed Matter Physics,Biomaterials,Electronic, Optical and Magnetic Materials
Cited by
2 articles.
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