Preparation And Properties Of Carbon Hydrid Composites For Supercapacitor

Graphene nanosheets (GNS) consisting of a single or multi-layer grapheme, high surface and excellent performance, have attracted more attentions on the carbon materials in recent years. However, graphene nanosheets will appear agglomeration during the preparation process, it is not satisfied the need of the electrochemical properties. In this paper, we try to introduce spherical carbon black into the grapheme layers in different ways; in order to increase the contact surface area between the electrolyte ion and the active substance, resulting in the improvement of the electrochemical performance. Carbon nanotubes have porosity similarities in its possession, and it is a good conductive material. So we introduce different content of carbon nanotubes in GNS/CB composites, to investigate its electrochemical performance, and we PANI on the GNS/CB/CNT composites. The microstructure and morphology of the samples were characterized by XRD and SEM and FT-IR. The electrochemical performances of the materials were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements, and the relationship of microstructure and electrochemical performance of composites was also investigated.We prepared GNS/CB composites by hydrazine reduction method and ultrasonication method. By inserting carbon black between the graphene layers of graphene, it not only inhibit the aggregation of graphene, but also increase the utilization of its surface. Carbon black also plays a role of supporting and conducting bridge between the layers. It is convenient for the electrolyte ions and electrons to transfer within the material, improving significantly the capacitance and power characteristics of the composites. In addition, this intercalated structure also makes the composite materials have excellent charge-discharge cycle stability and reversibility.We put different content of CNT into GNS/CB composites. The electrochemical performances of the materials were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements, and the relationship of microstructure and electrochemical performance of composites was also investigated. The result showed that the capacitance of GNS/CB/CNT hydrid composites with the improvement of CNT, this is because the surface of CNT is little, wounding together, it is difficult to dispersed by ultrasonication method. so the capacitance of GNS/CB/CNT become lower with the improvement of CNT content, decreasing the electrochemical properties of GNS/CB/CNT composites. Therefore, adding a small amount of CNT will improve the structure and properties of composites, instead of adding too much will play the opposite effect.As the different structure of nano-carbon matrix, we prepared the carbon/PANI composites by in situ polymerization method. Investigating the electrochemical properties of the composites, GNS/CB/CNT/PANI showed the excellent electrochemical properties, better than GNS/CB/PANI and GNSPANI. On the one hand carbon black surface can improve the utilization of grapheme, inserting between the graphene layers. On the other hand carbon black inserting into the graphene layers can also play a supporting role, opening ion transport electrolyte layer pore.At the same time graphene, carbon black and carbon nanotubes form a conductive three-dimensional structure of the whole conductive network. It is convenient for the electronics to transfer fast in the internal of composite materials, so that the GNS/CB/CNT/PANI composites have excellent electrochemical storage performance and cycle life.