High Performance Supercapacitors Based on the Electrodeposited Co3O4 Nanoflakes on Electro-etched Carbon Fibers

• Published in: Electrochimica acta Vol. 138; pp. 9 - 14
• Main Authors: Kazemi, S.H., Asghari, A., kiani, M.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20.08.2014
• Subjects: Carbon fiber; Cobalt oxide; Nanostructures; Supercapacitor; Cobalt oxide; Supercapacitor; Nanostructures; Carbon fiber
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2014.06.094

In the present work, excellent supercapacitive behavior of nanostructured Co3O4-ECF with outstanding cycling stability and capacitance retention was observed. These characteristics can be attributed to three dimensional (3D) structures of nanoflakes which allow facile electrolyte movement during charge or discharge processes. A specific capacitance of 598.9 F g(1 at a currents density of 3.1 A g(1 was obtained for Co3O4-ECF electrode in addition to high energy and power densities. •A facile method was introduced to prepare Co3O4 nanostructures for supercapacitor purpuoses.•Superior long-life stability and high specific capacitance at large current density were observed.•Capacitive behavior was remained almost constant after 1000 successive charge-discharge cycles. Present article introduces the electrochemical fabrication of cobalt oxide nanostructures on electro-etched carbon fiber (ECF) by a cathodic potential step method. The morphology and composition of the nanostructures were studied by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) and thermal analysis (TA) methods. FE-SEM images confirm the formation of flower-like Co3O4 nanoflakes on ECF (Co3O4-ECF). Cobalt hydroxide nanostructures transform into spinel structure after annealing in air at 300°C for 2hours. The electrochemical and supercapacitive performance of Co3O4-ECF was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) in both three and two electrode systems in KOH solution. Results confirm the excellent supercapacitive behavior of nanostructured Co3O4-ECF with excellent cycling stability and capacitance retention. These characteristics can be attributed to three dimensional (3D) structures of nanoflakes which allow facile electrolyte movement during charge or discharge processes. A specific capacitance of 598.9 F g−1 at a currents density of 6.25 A g−1 was obtained for Co3O4-ECF electrode in addition to high energy (40.75 Wh kg−1) and power densities (27.69kWkg−1).