| Graphene is a honeycomb lattice-Like novel two-dimensional nanomaterials composed of a single layer of carbon atoms, since its discovery, has aroused widespread concern and research. The extraordinary electronic, optical, thermal, mechanical and chemical properties endow graphene with a wide range of applications in many areas. The individual graphene sheets stacked together polymerization due to the strong ?-? bonds, which greatly reduced its specific surface area. What's more, the conductivity of graphene is greatly reduced because of cross-contact resistance and greater conductivity is greatly reduced. In order to overcome this obstacle, one possible solution is to prepare three-dimensional (3D) graphene architectures with high conductivity, large surface area and large porosity. The three-dimensional graphene composite is a good choice for the synthesis of new electrode material, due to the three-dimensional graphene prepared by chemical vapor deposition (CVD) has high conductivity, large porosity, low density, and large surface area. In this paper, we mainly prepared the three-dimensional graphene and three-dimensional graphene with other electrode active material for modifying structure and other aspects of performance, so that the prepared composites have better electrochemical performance in supercapacitors, lithium-ion battery and Hydrogen Evolution Reaction(HER). Our research work mainly is as these following aspects.In chapter three, we studied Super-Long Life Supercapacitors based on the construction of Ni foam/graphene/Co3S4 composite film hybrid electrodes. In this part of the study, Nickel foams, were used as 3D scaffold templates for the CVD growth of graphene. And then the 3D Ni/G/CS were prepared by a facile hydrothermal synthesis method. The 3D Ni/G/CS electrodes had high capacitance and excellent cycle stability, which maintained a 97.8% capacity after 8000 cycles. Single-layered, high quality graphene, which was coating on 3D Ni foam, has superior electrical conductivity. This leads to the fact that electrons can transport more efficiently. The formation of continuous Co3S4 films with hollow Co3S4 nanospheres on the surface of graphene leading to more efficient charge transportation and large improvement in capacitance. Ni foams can provide mechanical supported, and extremely high chemical stability of graphene can improve the stability during charge and discharge processes with large currently density.In chapter four, we studied ultrafast charge slow discharge LIBs and water splitting applications based on strongly coupled MoS2-3D graphene materials. In this part of the study, Nickel foams, were used as 3D scaffold templates for the CVD growth of graphene. Nickel foams was etched by HC1 solution. And then the receptaculum nelumbinis-like MoS2-3D graphene hybrid (RNL MoS2@GF) were prepared by a facile hydrothermal synthesis method. We found that the addition of graphene changed the structure of MoS2. MoS2 is formed RNL MoS2@GF overall framework. The RNL MoS2@GF used as electrode for LIBs anode exhibited superior rate capability and excellent cycle stability (maintained about 95.5% after 400 charge/discharge cycles), because of this stable structure of RNL MoS2@GF. When RNL MoS2@GF used as electrode for HER in acidic solutions, the catalyst exhibits a high catalytic activity and excellent stability. These results show that the RNL MoS2@GF is a Promising electrode for LIBs and HER. |
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