Synthesis and Characterization of CuO-NiO Nanocomposites for Electrochemical Supercapacitors

The CuO nanostructures and CuO-NiO nanocomposites of various compositions were successfully synthesized by simple hydrothermal method followed by calcination for investigation of their pseudocapacitive performances. The UV-vis spectroscopy, x-ray diffraction, field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy were used to characterize the as-synthesized electrode materials. Among these different CuO-NiO nanocomposites, CuO(x)NiO(100 - x), that's with equal mole ratio, CuO(50)NiO(50) exhibits the highest specific capacitance of 35.63 F g(-1) at current density of 0.3 A g(-1). In addition, it shows excellent cycling stability with capacity retention of 85.7% at 1000th cycle at current density of 10 A g(-1). The morphology of CuO(50)NiO(50) nanostructures as determined by FESEM and HRTEM studies, revealed aggregated three-dimensional (3D) hierarchical networks due to aggregation of various parallel 2D thin nanosheets. The supercapacitive activity of the synthesized CuO and CuO-NiO nanomaterials was found to follow the order: CuO(50)NiO(50) > CuO(20)NiO(80) > CuO(100) > CuO(80)NiO(20).