Facile synthesis of hierarchical Co3O4@MnO2 core–shell arrays on Ni foam for asymmetric supercapacitors

• Published in: Journal of power sources Vol. 252; pp. 98 - 106
• Main Authors: Huang, Ming, Zhang, Yuxin, Li, Fei, Zhang, Lili, Wen, Zhiyu, Liu, Qing
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-04-2014; Elsevier
• Subjects: Applied sciences; Capacitors. Resistors. Filters; Cobalt oxide; Core–shell; Electrical engineering. Electrical power engineering; Exact sciences and technology; Hierarchical; Manganese dioxide; Supercapacitors; Various equipment and components; Hierarchical; Cobalt oxide; Manganese dioxide; Supercapacitors; Core–shell; Cobalt Oxides; Transition metal; Electrolytic capacitor; Core-shell particle; Core-shell; Array; Metal foam; Supercapacitor; Manganese Oxides; Nickel; Chemical synthesis
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.12.030

Hierarchical Co3O4@MnO2 core–shell arrays on Ni foam have been fabricated by a facile hydrothermal approach and further investigated as the electrode for high-performance supercapacitors. Owing to the high conductivity of the well-defined mesoporous Co3O4 nanowire arrays in combination with the large surface area provided by the ultrathin MnO2 nanosheets, the unique designed Co3O4@MnO2 core–shell arrays on Ni foam have exhibited a high specific capacitance (560 F g−1 at a current density of 0.2 A g−1), good rate capability, and excellent cycling stability (95% capacitance retention after 5000 cycles). An asymmetric supercapacitor with Co3O4@MnO2 core–shell nanostructure as the positive electrode and activated microwave exfoliated graphite oxide activated graphene (MEGO) as the negative electrode yielded an energy density of 17.7 Wh kg−1 and a maximum power density of 158 kW kg−1. The rational design of the unique core–shell array architectures demonstrated in this work provides a new and facile approach to fabricate high-performance electrode for supercapacitors.
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•Hierarchical Co3O4@MnO2 nanowire array was prepared by a facile hydrothermal method.•MnO2 coated on Co3O4 nanowire without carbon coating or electrochemical deposition.•The unique core–shell architecture exhibits a high capacitance of 560 F g−1.•Excellent cycling stability: 95% capacitance retention after 5000 cycles.•The asymmetric supercapacitor yielded a maximum power density of 158 kW kg−1.