Preparation Of Carbon Aerogels At Ambient Pressure And The Research Of Its Composite

Carbon aerogel has very peculiar characteristics as a porous material,its porosity could be as high as80%to99.8%, the pore size is generally<50nm, belonging to the mesoporous materials, their specific surfaceareas up to200~1200m2/g. Because they have these peculiar structuralcharacteristics, the carbon aerogel has a wide range of applications inmany fields. Now the most used means of aerogel drying is supercriticaldrying, but supercritical drying is hard in the operation and cost, so tofind a more simple or easy drying means have a good meaning andvalue.In this article we use atmospheric pressure drying instead ofsupercritical drying. In this paper we try to find the best processes andparameters, in other wise we find some improved means to get a goodresult, such as modified and compound. In addition,we explore the carbonaerogel as the battery electrode materials,and achieved excellent results,this is one of the main work of this thesis.In this issue, the main substance is RF carbon aerogel, but we have different processes and means to deal with the aerogels: Preparation ofpure RF carbon aerogel at atmospheric pressure, the use of drying controladditives modified the RF carbon aerogel, RF carbon aerogel compositewith graphene. The modified means include in situ modification andsurface treatment modification, the compound means is also divided intoa common compound and hydrothermal synthesis. By controlling theparameters of temperature, catalyst concentration, reactant concentration,and solvent replacement and after surface treatment means, we got RFblock aerogel at atmospheric pressure. After analysis and testing,theresult show that the atmospheric Preparation of RF carbon aerogel has thesame property as the supercritical drying.The pore structure between2-70nm, typical of mesoporous materials, specific surface area up to550m2/g, the pore size distribution is more uniform mechanical and itselectrochemical properties is better, but also need to be improved, Bymodified,the aerogel sample has narrow distribution in pore size, the gelcracking collapse situation is good, very similar to the supercriticaldrying samples.It’s aslo a definite breakthrough in electrochemicalapplications, after the cyclic voltammetry, the modified aerogels stablecapacitance values up to400mAh/g, from310mAh/g which has notbeen modified.Carbon aerogel compound, the main work of the compound is aerogelwith graphene.Graphene composite has a great surface area and multi-porosity, the purpose is the composite product can integrate thetwo sides of the advantages, increased surface area and porosity, andgraphene has very good mechanical properties, improve structuralstability of the carbon aerogel is also a critical factor. The analysis ofelectron micrographs and subsequent electrochemical tests show that: thecomposite has been a very obvious improve as the battery anode material.In this experiment also uses a novel compound means-hydrothermalsynthesis. Hydrothermal Synthesis provide a high temperature andpressure, sealed conditions for the aerogel generating. The cyclicvoltammetry capacity of hydrothermal synthesis of aerogel samples up to430mAh/g.