Chemical synthesis and electrochemical analysis of nickel cobaltite nanostructures for supercapacitor applications

Nickel cobaltite (NiCo2O4) films containing nanorods and nanoflakes are synthesized on indium tin oxide (ITO) substrates by a chemical bath deposition method and calcination process at 300 degrees C for 3 h. The NiCo2O4/ITO films are used as electrodes for supercapacitor applications, and electrochemical properties of the NiCo2O4 nanostructures are examined by cyclic voltammetry and charge-discharge experiments. NiCo2O4 nanorods exhibit the largest specific capacitance, with a value of 490 F g(-1)at energy and power densities of 45Whkg(-1) and 2kWkg(-1), respectively. This is significantly better than the performance of NiCo2O4 nanoflakes. Cycle-life tests show that the specific capacitance of NiCo2O4 is stable even after 1000 cycles, indicating its high potential for supercapacitor applications. The low cost and environmental friendliness of NiCo2O4 nanorods, coupled with its high supercapacitor performance, offer advantages over other transition metal oxides used for supercapacitors. (C) 2011 Elsevier B.V. All rights reserved.