Mass-production And Electrochemical Energy Storage Of Graphene And Its Hybrid Materials

Supercapacitor is a green electrochemical energy storage device with high powerdensity, and its performance is largely affected by the structure and property of theelectrode materials. Generally speaking, carbon materials with high surface area andconductivity deliver high electric double layer capacity. Some metal hydroxides alsohave a high pseudocapacitance, but the severe volume expansion results in poor rateperformance and cyclic capability, which restricts its application in supercapacitors.Therefore, carbon materials were used to support the metal hydroxides to improve therate performance and cyclic capability. As the building block of carbon materials,graphene is characterized by a unique2D structure and excellent properties, such asthe high surface area and excellent conductivity, and shows great potential in the fieldof supercapacitors. The mass-production of graphene with high quality has been animportant factor in limiting its applications. In this thesis we conducted themass-production of graphite oxide, and use the as-obtained graphite oxide to preparecomposite materials with Ni(OH)2to develop high performance supercapacitorelectrode materials.This thesis mainly consists of the following three parts.1. Preparation of graphene is the foundation of the synthesis of graphene-basedmaterials, while mass-production of graphene is still an important factor which limitsits application. On basis of our previous accomplishment, this thesis discussed thepreparation process of graphene in detail, and successfully realized its massproduction. The as-prepared sample was compared with that obtained by traditionallaboratory-scale synthesis, and characterization results demonstrated feasibility of themass production approach.2. Graphite oxide prepared by the mass production and the laboratory-scalesynthesis were respectively used as the precursor to synthesize graphene/nickelhydroxide composites, and the influence of different synthesis strategies on theproperty of the composite was investigated. Results indicated that the electrochemicalperformance of the two composites were similar, which further verified the feasibilityof the mass production synthesis. 3. Graphite oxide prepared through the mass production synthesis was adopted asthe precursor, and electrochemical performance of the corresponding graphene/nickelhydroxide was further studied. Different fraction of nickel hydroxide, distinct dryingmethod and the introduction of conductive additive were also discussed in studyingand optimizing the electrochemical performance of the composite.