High supercapacitive performance of Ni(OH)2/XC-72 composite prepared by microwave-assisted method

Abstract

A 60 wt% Ni(OH)₂/XC-72 composite was synthesized via a facile and rapid microwave-assisted method in an ethylene glycol medium. Transmission electron microscopy images show that Ni(OH)₂ is uniformly dispersed on XC-72 and that when carbon nanotubes (CNTs) are added as a conductive agent, they construct a three-dimensional (3-D) network together with the Ni(OH)₂ particles and XC-72. The composite demonstrates a specific capacitance of 1296 F g⁻¹ at a scan rate of 2 mV s⁻¹ and 1560 F g⁻¹ at a current density of 1 A g⁻¹ in 6 M KOH aqueous solution, and its retention of specific capacitance is 71% after 1000 cycles. This can be attributed to XC-72 being an excellent support and CNTs with high aspect ratio and good conductivity to construct a 3-D conductive network. This excellent electrochemical performance makes the Ni(OH)₂/XC-72 composite promising as an electrode material for a supercapacitor.