Synthesis of Co3O4/NiO nanofilms and their enhanced electrochemical performance for supercapacitor application

Transition metallic oxides have attracted considerable attention for supercapacitor applications because of their superior electrochemical performance at relatively low cost. Co3O4/NiO nanofilms were successfully prepared by calcination of precursor alpha-Co(OH)(2)/alpha-Ni(OH)(2). XRD, XPS, SEM and TEM techniques were used to characterize the composition and morphology of as-prepared samples. The results demonstrated that Co3O4/NiO nanofilms presented graphene-like morphology with shrinkage and wrinkles. The Brunauer-Emmett-Teller (BET) measurement showed that specific surface area of Co3O4/NiO was 176.5 m(2)/g. Electrochemical properties tests indicated that the Co3O4/NiO nanofilms had a higher specific capacitance and better rate capability than that of precursor alpha-Co(OH)(2)/alpha-Ni(OH)(2) at high current density. As to the cycling performance, the specific capacitance of Co3O4/NiO electrode would first increase from 556 F/g to 710 Fig quickly at 2 A/g after 80 cycles and then remained stable. Therefore, compared with that of precursor alpha-Co(OH)(2)/alpha-Ni(OH)(2), the capacitance performance of as-prepared Co3O4/NiO nanofilms was improved after calcination. The possible reason for the enhancement of capacitance performance was discussed. (C) 2016 Elsevier B.V. All rights reserved.