Fabricating a Mn3O4/Ni(OH)2 Nanocomposite by Water-Boiling Treatment for Use in Asymmetric Supercapacitors as an Electrode Material

The electrode material is the key factor for developing asymmetric supercapacitors. A simple water-boiling treatment was adopted to fabricate a Mn3O4/Ni(OH)(2) nanocomposite on a large scale, which exhibited a splendid electrochemical performance with a boiling time of 3 h, achieving a capacitance of 742 F g(-1) at 1 A g(-1). When assembling the asymmetric capacitor with the Mn3O4/Ni(OH)(2) composite and activated carbon separately as positive and negative electrodes, a capacitance of 43 F g(-1) was attained at 0.2 A g(-1) with an energy density of 15.3 Wh kg(-1) at a power density of 168.8 W kg(-1). This simple, reproducible, ecofriendly, and large-scale fabrication method is practical for preparing other transition metal oxides for the purpose of use in asymmetric supercapacitors with superior properties.