Preparation Of Organic Functionalized Nano-carbon Composite Materials And The Investigation Of Electrochemical Behavior

Carbon nanomaterials mainly include the following three types: carbon nanofibers, carbonnanotubes, and graphene. They have many excellent physical and chemical properties, which havebeen widely used in many fields. However, without modification both carbon nanotubes and graphenewould have poor dispersion effect in the solvent for lacking surface functional groups, which willinfluence their applications in many fields. Therefore, many researchers focus on the functionalizationof carbon nanomaterials in order to expand the application value of carbon nanomaterials. Modifiedcarbon nanomaterials not only show their own advanced the physical and chemical properties, butalso improves the function of electronchemistry expanding the application of space. The tapes offunctionalization carbon nanomaterials can be divided into covalent functionalization and non-covalent functionalization.Although non-covalent functionalization has its own unique advantages in the functional process,for example, it can maintain the integrity of carbon nanomaterials itself by preventing destruction andoffering the special physical and chemical properties. But the van der Waals force between thefunctional groups and carbon nanomaterials is weak. Relatively, covalent functionalization couldobviously increase the stability and force between functional groups and carbon nanomaterials, whilethe non covalent functionalization is difficult to go beyond. Many studies indicate that, the preparationof carbon nanomaterials composites need covalent functionalization firstly and then through furthermodify by other chemical reaction, so it can improve the trim and the reaction between the carboncarrier and electrical conductivity. Therefore, covalent functionalization has great potential to improvethe electrochemical performance of carbon nanomaterials. Based on above analysis, this thesis hasfabricated the organic functional groups covalently to carbon nanomaterials firstly, and thenproceeded series of reactions with PANI grafting to synthetise composite materials. On the basis ofthese, we can study the electrochemical properties.(1) The carbon nanotubes would be functionalized as CNTs-NH2by acidification and oxidation,chlorination and amination reaction firstly. Then PANI-g-CNTs composite materials were synthetisedthrough the method of in situ polymerization at low temperature. Introduction of carbon nanotubescan not only increase the dispersion of carbon nanotubes itself, but also being growth sites for forminguniform grafted as the “core-shell” structure of carbon nanotubes in the growth process of PANI. Thecomposite material prepared by electrochemical testing results show that: at the current density of0.1A/g, the specific capacity can reach251.2F/g. At the0.5A/g current density, the composite material capacity retention was76.3%after1000charge discharge test, higher than that of PANI-c-CNTs57.4%significantly.(2) The PANI has been covalently grafted onto aminated carbon nanotubes surface by interfacialpolymerization method in the constant temperature system. Amino functionalized carbon nanotubesdispersed in water as the aqueous phase, and aniline monomer is dispersed to form the lower organicphase in CH2Cl2. PANI of the obtained composites has been coated on the surface of carbonnanotubes though this way. Then the Pt/PANI-g-CNTs have been fabricated by loading Pt nanoparticleon PANI-CNTs.The stability of Pt/PANI-g-CNTs is better than Pt/PANI-c-CNTs and Pt/C (JM-40%)in the accelerated aging experiment2000ring.(3) Graphene oxide was prepared by the traditional Hummers method, and then rGO-NH2wasobtained by reducing and functionalization GO with benzene two amine and reducing agent. Then theamino graphene as matrix was grafted PANI in situ at low temperature system. Then amination ofgraphene as the substrate in situ grafted PANI under the low temperature system. PANI grafted ontothe amino sites as prepared, forming PANI-g-rGO composite materials. The specific capacity ofresulting composite materials is up to315F/g at0.1A/g. Its capacity maintain in rate of67%after thecharge discharge test1000laps, much higher than that of PANI/GE of34.5%.