Preparation of porous CoMoO4 + NiMoO4 nanosheets with high capacitance by a sol–gel method and freezing method

Abstract

A cobalt molybdate and nickel molybdate blend was prepared by a sol–gel method and freezing method. Through correlation analysis of the morphology and phase, it was found that the prepared product has a porous sheet structure, which is a mixed junction of CoMoO₄ and NiMoO₄ (CoMoO₄ + NiMoO₄). According to the electrochemical performance results, the prepared electrode material has a high specific capacitance (2140 F g⁻¹ at 1 A g⁻¹) and excellent cycle stability (99.3% after 10 000 cycles at 5 A g⁻¹). In addition, the fabricated material and CNTs were assembled into an asymmetric device (CoMoO₄ + NiMoO₄//CNTs). The device has a high specific capacitance (142 F g⁻¹ at 1 A g⁻¹) and cycle stability (97.7% after 10 000 cycles at 5 A g⁻¹). At the same time, the device can provide a maximum energy density of 76.8 W h kg⁻¹ (current density of 1 A g⁻¹) and a maximum power density of 9563 W kg⁻¹ (current density of 15 A g⁻¹). The binary metal blend prepared in this work has excellent electrochemical performance, which is due to the combination of cobalt molybdate and nickel molybdate, and the effective use of the synergistic effect of the two.