Synthesis of Ni(Co)MoO4 with a mixed structure on nickel foam for stable asymmetric supercapacitors

In this work, the Ni(Co)MoO4 (NMO-Co) hybrid materials with nanoneedle and nanosheet structure were prepared on nickel foam (NF) by the hydrothermal method for high-stability supercapacitors. The effect of Co presence on the structure and electrochemical properties of NMO-Co was investigated. As the molar of Cobalt increased, more nanoneedles grew on the surface of NiMoO4/NF. The combination of the Ni-doped CoMoO4 nanoneedles and Co-doped NiMoO4 nanosheets was irregularly arranged on the surface of NF, which emerged an improvement of the cycling performance. When the molar ratio of Co: Ni: Mo was 0.5: 1: 1, the capacitance retention of the hybrid electrode was 80.1% after 10,000 cycles at 10 A g-1, while the pure NiMoO4 electrode was 53.1%. Moreover, an asymmetric supercapacitor device displayed high energy density and power density. The maximum energy density and power density could reach 55.71 Wh kg-1 and 14,999 W kg-1, respectively. The hybrid electrode's good electrochemical performance is due to the combination of mutual doping of Ni and Co with a mixed morphology. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this research, Ni(Co)MoO4 hybrid materials with nanoneedle and nanosheet structure were successfully prepared on nickel foam by the hydrothermal method for high-stability supercapacitors. The presence of Co was found to increase the growth of nanoneedles on the surface of NiMoO4/NF, leading to improved cycling performance and capacitance retention. By controlling the molar ratio of Co, better electrochemical performance was achieved, resulting in a high energy density and power density in the asymmetric supercapacitor device. The good performance of the hybrid electrode is attributed to the mutual doping of Ni and Co with a mixed morphology.