Co0.56Ni0.44 Oxide Nanoflake Materials and Activated Carbon for Asymmetric Supercapacitor

In this work, Co0.56Ni0.44 oxide nanoflakes with a maximum specific capacitance of 1227 F/g (136 mAh/g) are successfully synthesized by a facile chemical coprecipitation method. To enhance energy density, an asymmetric supercapacitor with high energy and power density has been constructed with Co0.56Ni0.44 oxide nanoflakes as the positive electrode and activated carbon as the negative electrode. The performance of the asymmetric supercapacitor was characterized by cyclic voltammetry and chronopotentiometry technology. By using the nanoflakes Co0.56Ni0.44 oxides electrode, the asymmetric supercapacitor exhibits high energy density and stable power characteristics; the maximum specific capacitance of 97 F/g and specific energy of 34.5 W h/kg are demonstrated for a cell voltage between 0 and 1.6 V. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3497298] All rights reserved.