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

Abstract

Abstract Chemical doping of nickel hydroxide with other cations ( e.g. Al 3+ ) is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation–anion (Ni 2+ and AlO 2 − ) 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.