Journal of Power Sources, Vol.240, 338-343, 2013
Preparation and electrochemical performances of nanostructured CoxNi1-x(OH)(2) composites for supercapacitors
Nanostructured CoxNi1-x(OH)(2) (x = 0, 0.053, 0.068, 0.116, 0.192) composites are synthesized via a simple template-free growth process onto nickel foam by using a mixed aqueous solution of nickel nitrate, cobalt nitrate and ammonia. Their structure and surface morphology are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy. The SEM images show changes in the microstructure of beta-Ni(OH)(2) by the doping of cobalt. The effects of cobalt content on the electrochemical behaviors of beta-Ni(OH)(2) are investigated by cyclic voltammetries, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show that the Co0.116Ni0.884(OH)(2) composite electrode exhibits a drastic improvement in the capacitive characteristics of beta-Ni(OH)(2) with a specific capacitance increase from 386.4 to 1082.6 F g(-1) at a high discharging current density of 6 A g(-1). This work suggests that the as-prepared Co0.116Ni0.884(OH)(2) composite electrode has a promising future as higher charging/discharging rate materials for pseudo-supercapacitors. (C) 2013 Elsevier B.V. All rights reserved.