Growth of highly mesoporous CuCo2O4@C core-shell arrays as advanced electrodes for high-performance supercapacitors

A series of CuCo2O4 nanostructures with different morphologies were prepared by a hydrothermal method in combination with thermal treatment. The morphology, structure and composition were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. As the electrode materials for supercapacitors, CuCo2O4 nanoneedles delivered the highest specific capacitance compared with other CuCo2O4 nanostructures. Electrochemical performance measurements demonstrate that the carbon layer can improve the electrochemical stability of CuCo2O4 nanoneedles. The CuCo2O4@C electrode exhibits a high specific capacitance of 1432.4 F g(-1) at a current density of 1 A g(-1), with capacitance retention of 98.2% after 3000 circles. These characteristics of CuCo2O4@C composite are mainly due to the unique one dimensional needle-liked architecture and the conducting carbon, which provide a faster ion/electron transfer rate. These excellent performances of the CuCo2O4@C electrode confirmed the material as a positive electrode for hybrid supercapacitor application. (C) 2018 Elsevier B.V. All rights reserved.