Synthesis And Characterization Of Graphene Aerogel And Film

Graphene aerogel has three-dimensional structure which is made up of highly dispersed graphene. It not only has the excellent mechanical, thermal, and electrical performance of graphene, but also has the light and porous performance of aerogel. Graphene film is one of the hot topics in graphene research fields. Therefore, it is very important to investigate the structures and properties of graphene aerogel and film.The main research contents of this paper include synthesis of graphene aerogel and film, investigation of effecting factors (different concentrations of graphene oxide solution, doping carbon nanotube mass percent, reaction time, reaction temperature, and the reduction methods of graphene aerogel), and the influences of carbonization temperature on the conductive properties, microstructure and electrochemical properties of graphene film. The main conclusions of this paper are as follows:Hydrothermal reduction method is more advantageous approach to the preparation of graphene aerogel with low density, and good resistance to compressibility by comparing the hydrothermal reduction and ascorbic acid reduction in the preparation of graphene aerogel.The effects of graphene oxide concentration, time and temperature of hydrothermal reduction on the formation of graphene aerogel were explored using graphene oxide solution prepared by modified Hummers method as the raw material. The results indicate that when the graphene oxide concentration is 2.0mg ml-1, and the volume of 30ml, in hydrothermal condition for 12h,180℃ graphene hydrogel can be obtained. Lightweight (0.74mg cm-3), compression resistance (Young’s modulus 0.048MPa), conductivity (0.84s m-1) of graphene aerogel can be made by freeze-dried method.In order to investigate the influence on the formation of doping carbon nanotubes composite graphene aerogel and the optimal doping ratio, the above conditions of hydrothermal reduction process were used. The results indicate that doping with 20% mass fraction of carbon nanotubes composite graphene aerogel with low density of 1.94mg cm-3 has better conductivity (1.69s m-1) and compression resistance (Young’s modulus 0.014MPa).Graphene oxide film was prepared by vacuum filtration method using graphene oxide solution (0.2mg ml-1,15ml). The results indicate that the conductivity and specific capacity of the film will increase with the increase of carbonization temperature. The sample shows excellent performace in conductivity (37.6s m-1) and electrochemistry (79.83F g-1) at 1300℃ carbonization temperature.