Effect of Al-doped β-Ni(OH)2 nanosheets on electrochemical behaviors for high performance supercapacitor application

Al-doped beta-Ni(OH)(2) nanosheets are prepared by a simple hydrothermal process onto nickel foam by using a mixed aqueous solution of nickel nitrate, aluminum nitrate and ammonia. Their structure and surface morphology are studied by using X-ray diffraction analysis, energy-dispersive X-ray spectroscopy and scanning electron microscopy. The SEM images show changes in the microstructure of beta-Ni(OH)(2) by the addition of Al. The XRD results show that the alpha-phase Ni(OH)(2) appeared by the addition of Al. The effects of Al content on the electrochemical behaviors of beta-Ni(OH)(2) are investigated by cyclic voltammetrys, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show a drastic improvement in the capacitive characteristics of beta-Ni(OH)(2) with a specific capacitance increase from 941.7 to 2122.6 F g(-1) by the addition of just 3.4 mol% Al. This work suggests that the as-prepared Al0.034Ni0.966LDH electrode has a promising future as higher charging/discharging rate materials for pseudo-supercapacitors. (C) 2013 Elsevier B.V. All rights reserved.