Ni-Al composite hydroxides fabricated by cation-anion double hydrolysis method for high-performance supercapacitor

Chemical doping of nickel hydroxide with other cations (e.g. Al3+) is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation-anion (Ni2+ and AlO2-) double hydrolysis method was developed toward the synthesis of nickel-aluminum (Ni-Al) composite hydroxides. The obtained composite hydroxides possesses a porous structure, large surface area (121 m(2)/g) and homogeneous element distribution. The electrochemical test shows that the obtained composite hydroxides exhibits a superior supercapacitive performances (specific capacitance of 1670 F/g and rate capability of 87% from 0.5 A/g to 20 A/g) to doping-free nickel hydroxide (specific capacitance of 1227 F/g and rate capability of 47% from 0.5 A/g to 20 A/g). Moreover, the galvanostatic charge/discharge test displays that after 2000 cycles at large current density of 10 A/g, the composite hydroxides achieves a high capacitance retention of 98%, indicative of an excellent electrochemical cycleability. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.