One-pot synthesis of a Ni-Mn3O4 nanocomposite for supercapacitors

Ni-Mn3O4 nanocomposite has been prepared successfully by chemical oxidation in an alkaline solution of Mn2+ on the surface of Ni nanoparticles with OH functional groups using one-pot method. The obtained Ni-Mn3O4 nanocomposite was characterized using a scanning electron microscope (SEM), a transmission electron microscope (TEM), X-ray diffraction (XRD) analysis and various electrochemical techniques, such as cyclic voltammetry (CV), galvanostatic charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS). The average crystal sizes of Mn3O4 were found to decrease linearly with increasing Ni content in the Ni-Mn3O4 composite. The Ni-Mn3O4 nanocomposite could be easily conditioned and inverted to birnessite-type MnO2. A specific capacitance of 230 F g(-1) (based on pure Mn3O4) was obtained for the Ni (17.3%)-Mn3O4 nanocomposite at a current rate of 0.25 A g(-1), and 94% of the initial capacitance was retained after 1000 GC/D cycles at a current rate of 1 A g(-1). It is concluded that the Ni-Mn3O4 nanocomposite is a promising electrode materials for supercapacitors. (C) 2015 Elsevier B.V. All rights reserved.