Controllable Preparation And Properties Of Flexible Graphene Fibers

In this study, graphene oxide was synthesized by using graphite as raw material via modified Hummers method. Through using ascorbic acid as reducing agent, graphene fibers can obtained by using low temperature induced chemical reduction self-assembly. After the analysis of FT-IR and XRD, The fibers have been reduced betterly. From the high power scanning electron microscopy, the surface of the graphite fiber is smooth and the diameter of graphite fiber is about 130 um, the orientation of the graphene sheet is obvious. The fracture strength of graphene fiber reached to 236 MPa, which shows good mechanical flexibility. In order to further explore the electrochemical properties of graphene. Electrochemical performance test was carried out at the current density of 200 mAh g-1 with a three electrode test system by using graphene fiber as the flexible working electrode. The measured capacitance is as high as 185.7F g-1, the capacitance remains the same as the original 75% after 500 cycles, it can reach to 140.8F g-1, which reflects the stability of the cycle. In order to further improve its electrochemical performance, composite fibers were successfully prepared by using the excellent performance of CNTs and MnO2.The capacitance also has a significant increases. It is in the same situation that the graphene / carbon nanotube composite fibers are almost the same as the breaking strength of graphene fibers, The measured capacitance is 245.2Fg-1, The electrochemical properties of graphene / MnO2 composite fiber is more excellent, The measured capacitance is as high as 363.2F g-1, And this two kinds of composite fibers have shown better cycle performance after the cyclic tests.