Synthesis and characterization of mesoporous Ni-Co oxy-hydroxides for pseudocapacitor application

Abstract

Mesoporous binary nickel-cobalt (Ni-Co) oxy-hydroxides have been obtained through the microwave-assisted hydrothermal annealing (MAHA) method. The porosity control of the nanostructured Ni-Co oxy-hydroxide nanoparticles is achieved through adding the pluronic triblock copolymer F127 as the surfactant. The structural and electrochemical properties of porous Ni-Co oxy-hydroxide nanostructures are characterized by means of X-ray diffraction (XRD), Brumauer-Emmett-Teller (BET) analysis, transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and cyclic voltammetry (CV). The electrochemical measurement demonstrates that the Ni-Co oxy-hydroxides calcined at 200 °C are able to deliver a specific capacitance of 636 F g-1 in 1 M NaOH, suggesting their high potential as a novel electrode material of pseudocapacitors with good electrochemical reversibility. In the asymmetric supercapacitor test, the positive electrode is Ni-Co oxy-hydroxide and negative electrode is activated carbon. The specific energy and power, measured at 2 A g-1, for this asymmetric combination are equal to ca. 17 Wh kg -1 and 1.6 kW kg-1, respectively. © 2013 Elsevier Ltd. All rights reserved.