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Issue 45, 2019
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2.5 V salt-in-water supercapacitors based on alkali type double salt/carbon composite anode

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Abstract

Due to the advantages of safe, cost-effective and environment friendly, aqueous high-voltage carbon/carbon supercapacitors attract much attention but the poor cycling stability hinders their practical applications. In this study, by electrodepositing a Zn/Zn4SO4(OH)6·4H2O (ATDS) composite on a microporous carbon cloth modified with basic functional groups (OCC) as a negative electrode, we developed an aqueous carbon/carbon supercapacitor operating steadily at a voltage as high as 2.5 V. The ATDS composite expands the negative potential window of carbon to −1.7 V vs. SCE and thus makes the positive carbon cloth (CC) operate in the stable potential range to inhibit the capacity degradation of the supercapacitor. A 2.1 V beaker-shaped supercapacitor of ATDS@OCC//CC presents almost 100% capacity retention after 19 000 cycles at 18 mA cm−2. Moreover, the cycled 2.1 V ATDS@OCC//CC supercapacitor exhibits the improved energy density of 9 mW h cm−3 and better retention of the energy density. A 2.5 V ATDS@OCC//CC supercapacitor after 4900 cycles exhibits about 100% capacity retention, an ultrahigh volumetric energy density of 20 mW h cm−3 and a mass energy density of 29 W h kg−1. The novel strategy may pave the way for developing safe, environment friendly and high-energy carbon/carbon supercapacitors.

Graphical abstract: 2.5 V salt-in-water supercapacitors based on alkali type double salt/carbon composite anode

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Publication details

The article was received on 04 Aug 2019, accepted on 14 Oct 2019 and first published on 15 Oct 2019


Article type: Paper
DOI: 10.1039/C9TA08490H
J. Mater. Chem. A, 2019,7, 26011-26019

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    2.5 V salt-in-water supercapacitors based on alkali type double salt/carbon composite anode

    T. Qin, Z. Xu, Z. Wang, S. Peng and D. He, J. Mater. Chem. A, 2019, 7, 26011
    DOI: 10.1039/C9TA08490H

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