Nanocomposite of copper-molybdenum-oxide nanosheets with graphene as high-performance materials for supercapacitors

We describe a facile and low-cost hydrothermal method to synthesize hierarchical CuMoO4 nanosheets (NS-CuMoO4) and their composite with graphene (NS-CuMoO4/rGO) on a nickel foam (NF) substrate without any binders. Maximum specific capacitances of 2342 and 1300 Fg(-1) at a current density of 1.8 A g(-1) were estimated for NS-CuMoO4/rGO/NF and NS-CuMoO4/NF electrodes, respectively. Furthermore, the NS-CuMoO4/rGO/NF electrode maintained 86% of its initial capacitance when the current density increased from 1.8 to 16.5 A g(-1), which indicates an exceptional rate capability. Notably, the NS-CuMoO4/rGO/NF electrode showed an excellent cycling stability of more than 98% over 4000 successive cycles, which was higher than the NS-CuMoO4/NF electrode with an 88% specific capacitance retention. Moreover, an asymmetric supercapacitor was assembled using NS-CuMoO4/rGO/NF that showed excellent performance with high energy/power densities and a substantial cycling stability. Our findings suggest the NS-CuMoO4/rGO/NF electrode has potential for future applications in high-performance supercapacitors. (C) 2019 Elsevier B.V. All rights reserved.