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 ([email protected]@NCS) on Ni foam (NF) is reported, in which the composite nanoparticles of CNTs and Ni3V2O8 ([email protected]) and the NiCo2S4 (NCS) nanosheets around [email protected] 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 ∼ 81.8% of its initial capacitance and ∼ 100% Coulombic efficiency over 10,000 cycles at 10 mA cm−2 can be maintained. An aqueous asymmetric supercapacitor assembled using [email protected]@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 ∼ 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.