Effect of Ultrasonic Time for Graphite Oxide on the Structure and Super Capacitor Performance of Three-dimensional Reduced Graphene Oxide

Three-dimensional reduced graphene oxide(3DRGO) was prepared from graphene oxide(GO) with different ultrasonic time by one-step hydrothermal method. X-Ray diffraction(XRD), Raman spectroscopy, atom force microscopy (AFM), scanning electron microscopy (SEM) and elctrochemical measurements were used to investigate the structure and supercapacitive performance of 3DRGO. The results show that when the ultrasonic time is less than 120 min, stabilized three-dimensional structure can be formed in the hydrothermal reduced graphene oxide. Along with the increase of the ultrasonic time, the size of 3DRGO decrease while the strength increase, and the inner structure of 3DRGO transforms from schistose to network. When the ultrasonic time is longer than 120 min, the stability of the network in 3DRGO is inferior on a macro level. The results of electrochemical measurements show that all the 3DRGO samples prepared with different ultrasonic time have good supercapacitive performance. The sample prepared with 120 min has the best supercapacitive performance for its well-proportioned network. The capacity can reach 328 F/g at the current density of 1 A/g and 240 F/g at the high current density of 20 A/g.