title: Charge storage mechanisms of manganese oxide nanosheets and N-doped reduced graphene oxide aerogel for high-performance asymmetric supercapacitors.
abstract: Although manganese oxide- and graphene-based supercapacitors have been widely studied, their charge storage mechanisms are not yet fully investigated. In this work, we have studied the charge storage mechanisms of K-birnassite MnO2nanosheets and N-doped reduced graphene oxide aerogel (N-rGOae) using an in situ X-ray absorption spectroscopy (XAS) and an electrochemical quart crystal microbalance (EQCM). The oxidation number of Mn at the MnO2electrode is +3.01 at 0 V vs. SCE for the charging process and gets oxidized to +3.12 at +0.8 V vs. SCE and then reduced back to +3.01 at 0 V vs. SCE for the discharging process. The mass change of solvated ions, inserted to the layers of MnO2during the charging process is 7.4 μg cm-2. Whilst, the mass change of the solvated ions at the N-rGOaeelectrode is 8.4 μg cm-2. An asymmetric supercapacitor of MnO2//N-rGOae(CR2016) provides a maximum specific capacitance of ca. 467 F g-1at 1 A g-1, a maximum specific power of 39 kW kg-1and a specific energy of 40 Wh kg-1with a wide working potential of 1.6 V and 93.2% capacity retention after 7,500 cycles. The MnO2//N-rGOaesupercapacitor may be practically used in high power and energy applications.
authors.affiliation: Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.|Department of Chemical Engineering, Kasetsart University, Bangkok 10900, Thailand.
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authors.affiliation: Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.
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authors.affiliation: Department of Chemical Engineering, Kasetsart University, Bangkok 10900, Thailand.
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authors.affiliation: Department of Materials Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.
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authors.affiliation: Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.
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