Three-dimensional nanostructured NiO-Co3(VO4)2 compound on nickel foam as pseudocapacitive electrodes for electrochemical capacitors

An advanced binder-free electrode for high-performance supercapacitors has been designed by growing 3D nanostructured NiO-Co-3(VO4)(2) compound on nickel foam. Such unique nanocomposite combined separately the advantages of the perfect cycling stability and rate capability of Co-3(VO4)(2) and the high specific capacitances of NiO. Furthermore, the nanostructure of NiO-Co-3(VO4)(2) could provide higher specific surface area and more active sites. As a result, this electrode exhibited remarkable specific capacitances of 1166 F g(-1) at a current density 0.5 A g(-1), perfect cycle stability of cycle efficiency 99.4% after 5000 cycles and excellent electrochemical performance than the single oxide electrodes. To enhance energy density, the asymmetric supercapacitor was assembled where NiO-Co-3(VO4)(2) and activated carbon acted as the positive and negative electrodes, respectively. The maximum specific capacitance of 109 F g(-1) and the specific energy of 38.8Wh kg(-1) are demonstrated for a cell voltage between 0 and 1.6 V, exhibiting a high energy density and stable power characteristics. And this work also demonstrates the feasibility of rational design of advanced integrated compound electrode for high-performance supercapacitors. (C) 2014 Elsevier B.V. All rights reserved.