TY - JOUR
T1 - Enabling Effective Thiocyanogen/Thiocyanate Couple for the Zinc─Pseudohalogen Battery
AU - Gao, Kun
AU - Li, Shuning
AU - Liu, Jiajia
AU - Yang, Tian
AU - Yu, Wenjing
AU - Ju, Shidi
AU - Zhang, Shaohua
AU - Zhang, Zhipan
N1 - Publisher Copyright:
© 2023 Wiley-VCH GmbH.
PY - 2023/11/16
Y1 - 2023/11/16
N2 - Pseudohalogens 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.
AB - Pseudohalogens 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.
KW - nonmetal cathodes
KW - thiocyanogen/thiocyanate redox couple
KW - water-in-salt electrolytes
KW - zinc─pseudohalogen batteries
UR - http://www.scopus.com/inward/record.url?scp=85169475948&partnerID=8YFLogxK
U2 - 10.1002/adfm.202307641
DO - 10.1002/adfm.202307641
M3 - Article
AN - SCOPUS:85169475948
SN - 1616-301X
VL - 33
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 47
M1 - 2307641
ER -