Electrodeposition of three-dimensional Ni(OH)2 nanoflakes on partially crystallized activated carbon for high-performance supercapacitors

Abstract

Three-dimensional Ni(OH)2 nanoflakes were prepared via a facile and cost-effective electrodeposition method using commercial activated carbon (AC) as substrate. Nitric acid treatment (NT) and partial crystallization (PC) by metal nickel catalysis were applied for AC. The effects of the oxygen-containing functional groups and the degree of crystallization on the electrochemical performance of the electrode were investigated. The resulting Ni(OH)2/PC–NT–AC/nickel foam electrode exhibits distinct performance with a specific capacitance of 2971 F/g (scaled to the mass of active Ni(OH)2) at a current density of 6 A/g. A high capacitance of 1919 F/g was still achieved even at 40 A/g, which is much higher than Ni(OH)2/AC/nickel foam electrode and Ni(OH)2/NT–AC/nickel foam electrode. The excellent performance of Ni(OH)2/PC–NT–AC/nickel foam electrode can be attributed to the presence of large surface area and highly conductive PC–NT–AC network on nickel foam. This study presents an effective method to improve the dispersion and rate capability of Ni(OH)2 nanostructure electrodes.