Boosting the capacitance of NiCo2O4 hierarchical structures on nickel foam in supercapacitors

A facile method of directly growing NiCo2O4 hybrid hierarchical nanostructures on nickel foam is developed by a hydrothermal and post heat-treatment method without using any surfactant, stabilizer or organic binder. Due to the rich porous nanostructures, relative large specific surface area (177.71 m(2) g(-1)) of the NiCo2O4 hybrid structure and efficient electrical contact with the conductive nickel substrate, the NiCo2O4-NF hybrid electrode shows significantly enhanced specific capacitance (3105.1 F g(-1) at 1 A g(-1)), outstanding rate properties (1621.3 F g(-1) at 20 A g(-1) and 1191.5 F g(-1) at 50 A g(-1)) and high energy density (95.26 Wh kg(-1)). This facile and effective design method opens up new possibilities for producing binder-free electrodes in high-performance electrochemical supercapacitors and miniaturized devices. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.