Carbon nanotubes@Ni3V2O8@NiCo2S4 nanosheets on Ni foam as a cathode for high-performance aqueous supercapacitors

Herein, a high-performance supercapacitor cathode composed of carbon nanotubes (CNTs)@Ni3V2O8@NiCo2S4 nanosheets (CNTs@NVO@NCS) on Ni foam (NF) is reported, in which the composite nanoparticles of CNTs and Ni3V2O8 (CNTs@NVO) and the NiCo2S4 (NCS) nanosheets around CNTs@NVO are synthesized by hydrothermal growth and electrodeposition, respectively. A high specific capacitance of 8722.0 mF cm(-2) at 1 mA cm(-2) together with good rate performance, i.e., 7337.6 mF cm(-2) at 16 mA cm(-2) and 4560.0 mF cm(-2) even at 60 mA cm(-2) is delivered by the electrode. Cycling test indicates that similar to 81.8% of its initial capacitance and similar to 100% Coulombic efficiency over 10,000 cycles at 10 mA cm(-2) can be maintained. An aqueous asymmetric supercapacitor assembled using CNTs@NVO@NCS on NF as the cathode, the activated carbon on carbon cloth as the anode and the 2 M KOH aqueous electrolyte delivers good cycle performance with similar to 14.1% total capacitance decay after 10,000 cycles at 20 mA cm(-2) and an energy density as high as 0.414 mWh cm(-2) at 0.800 mW cm(-2). In view of facile preparation and excellent performance, this research provides a meaningful and valuable exploration for designing and fabricating high-performance cathodes and the related energy storage devices.

Automated summary

A high-performance supercapacitor cathode composed of carbon nanotubes and nanosheets is reported, delivering high specific capacitance, good rate performance, and excellent cycling stability. Furthermore, an asymmetric supercapacitor assembled with this cathode shows good cycle performance and high energy density after 10,000 cycles.