| Supercapacitors, known as electrochemical capacitors, play a very important role in energy storage and conversion for electric devices. Supercapacitors have many advantages, such as high power density, long cycle life, and fast chargingdischarging rates. Many carbon-based materials have been investigated as electrode materials for supercapacitors due to their intriguing properties including low cost,non-toxic, environmental friendliness and stability. In the family of carbon materials,graphene is considered as a promising material for the next-generation supercapacitors because of its high specific surface area, excellent electrical conductivity, and high theoretical specific capacitance. It predicts that the specific capacitances of graphene could reach 550 F g-1, but the specific capacitance of most supercapacitors based on graphene is low, even lower at a large current density, it is less than 40 F g-1 at a large current density of 10 A g-1.We use graphite oxide?GO? as basic raw material, it has been reactived with boron nitride, liquid phase exfoliated graphene?LG? to prepared boron nitride /reduced graphene oxide?BN/RGO?, folded three-demensional graphene?FTG?composites. Then the as produced products were applied to supercapacitors applications in energy storage. The inorganic composites, effectively alleviates the agglomeration and restacking of graphene nanosheet, and benefit the contact between the electrolyte solution and electrode materials. Of these inorganic composites materials for energy storage applications of graphene in the field of the discussion, they have important scientific significance. Therefore, the research of graphene two inorganic composite material has important potential application value in the field of energy and chemical. The main research work of this thesis are the following two points:1. BN/RGO nanocomposites were synthesized by a facile liquid phase exfoliation method. And the supercapacitors based on these composites show a high specific capacitance(140 F g-1 at the current density of 2 A g-1), good rate performance(71.5 F g-1at 50 A g-1), and excellent cyclic stability(105.5% capacitance retention after 1000 cycles at a large scan rate of 200 m V s-1). These remarkable electrochemical performances imply that the BN/RGO nanocomposites would have great potential applications in supercapacitors.2. FTG is prepared through assembly of GO and LG, followed by sonication and reduction processes. The obtained FTG consists of few-layer graphene. And it possesses high degree of crystallinity, three-dimensional architecture and uniformly distributed mesopores. Supercapcacitor based on FTG electrode exhibits enhanced electrochemical performance. The FTG electrode exhibits high specific capacitance of195.4 F g-1 at a scan rate of 1 m V s-1 and excellent cycling stability with 93.9% of its initial capacitance at a large scan rate of 500 m V s-1 after 8000 cycles. These results suggest that FTG is a promising material for high-performance supercapacitor applications.The innovation of this paper is prepared graphene composites without metal and for supercapacitors applications in energy research, provides a kind of green energy storage materials. And these composites have a good performances in energy storage,the synthetic method is simple, beneficial to industrialization. Thus these composites based on reduced graphene oxide have the great potential application value in energy and chemical industry. |
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