Characterization and electrochemical properties of CuO–Cu2O@rGO nanocomposite synthesized by a seed-mediated growth process

A CuO–Cu2O@rGO nanocomposite (CuO–Cu2O@rGO NCP) has been successfully prepared through a seed-mediated growth process. X-ray diffraction (XRD) analysis results indicated a monoclinic phase of CuO–Cu2O@rGO NCP with space group C2/c. Transmission electron microscopy (TEM) revealed agglomeration of the CuO and Cu2O nanoparticles in the rGO sheet matrix. The interaction of CuO–Cu2O@rGO NPC resulted from the aggregation and overlapping of CuO and Cu2O nanoparticles owing to the influence of a seed-mediated growth process. The electrochemical properties of the CuO–Cu2O@rGO NPC electrode indicate the storage of energy at the surface through a pseudo-capacitive mechanism. The specific capacitance at a current density of 0.5 A g−1 and the average percentage capacity retention after 1000 cycles of a CuO–Cu2O@rGO electrode at a current density of 10 A g−1 were evaluated as 125.54 F g−1 and 89.87 ± 3.30%, respectively. In the CuO–Cu2O@rGO electrode, the incorporated rGO affects the electrical conductivity and the synergistic interactions in charge–discharge processes. Interestingly, these results showed that the material was synthesized through a seed-mediated growth process and reveal the key factors that determine the combination and volume expansion of the reversible redox transition between Cu+ and Cu2+ during charge–discharge processes.