Applied Surface Science, Vol.441, 251-257, 2018
Pseudocapacitive performance of electrodeposited porous Co3O4 film on electrophoretically modified graphite electrodes with carbon nanotubes
A facile and efficient two-step procedure was developed for the fabrication of a high-performance and binder-free cobalt oxide-carbon nanotubes (CO/CNT) pseudocapacitive electrode. First, CNTs were deposited on the surface of a chemically activated graphite sheet by cathodic electrophoretic deposition technique from their ethanolic suspension. In the next step, a thin film of cobalt oxide was electrode posited on the CNTs coated graphite substrate by a galvanostatic method, followed by a thermal treatment in air. The structure and morphology of the prepared cobaltite electrode with and without CNT interlayer were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and nitrogen adsorption-desorption measurement. The results indicated that Co3O4 nanoparticles were uniformly attached on the surface of CNTs, to form a porous-structured CO/CNT composite electrode with a high specific surface area of 144.9 m(2) g (1). Owing to the superior electrical conductivity of CNTs, high surface area and open porous structure, and improved integrity of the electrode structure, the composite electrode delivered a high areal capacitance of 4.96F cm (2) at a current density of 2 mA cm (2), a superior rate performance (64.7% capacitance retention from 2 mA cm (2) to 50 mA cm (2)), as well as excellent cycling stability (91.8% capacitance retention after 2000 cycles), which are higher than those of the pure cobaltite electrode. (C) 2018 Elsevier B.V. All rights reserved.
Keywords:Cobalt oxide;Carbon nanotubes;Electrophoretic deposition;Electrodeposition;Supercapacitor;Electrochemical performances