MWCNTs-GONRs/Co3O4 electrode with needle-like arrays for outstanding supercapacitors

Abstract

Multiwalled carbon nanotubes-graphene oxide nanoribbons (MWCNTs-GONRs) exhibit high specific surface area and good electroconductivity because of their unique three-dimensional cross-linking structure with the properties of both CNTs and GONRs. In this study, a hydrothermal method was employed to anchor MWCNTs–GONRs onto a Ni foam (NF) to obtain a precursor substrate. Subsequently, Co3O4 arrays were grown on the NF substrate to synthesize a MWCNTs–GONR/Co3O4 electrode. The electrode showed a capacitance of 846.2 F g−1 at 1 A g−1 and a capacitance retention of 90.1% after 3000 cycles. Furthermore, MWCNTs–GONRs/Co3O4 and active carbon (AC) were used as the positive and negative electrodes, respectively, to assemble a supercapacitor, which delivered a maximum energy density of 38.23 W h kg−1 and a high power density of 6.80 kW kg−1. In addition, the specific capacitance of the device reached a maximum of 91.5% after 9000 cycles. Thus, the MWCNTs–GONRs/Co3O4 electrode showed huge potential for supercapacitor applications.