Study On The Structure Of Amphiphilic Carbonaceous Material And Its Applications In Electrode Materials

Amphiphilic carbonaceous material (ACM), a material with high carbon content, economic cost, low volatile and ash content as pitch or coke, is soluble in alkaline aqueous solution, plenty in functional groups, and thermohardening. Based on these properties, no organic solvent and stabilization process is needed during the thereof carbon materials preparation from ACM. Therefore, ACM is economic, facile, and green in carbon materials production. It is necessary to study the structure of ACM and develop its applications in energy storage.In this paper, structure of ACM was studied via various characterization methods. It is confirmed that O, N, and S atoms were introduced into ACM by a series of combinated reactions including carboxylation, nitration and sulfonation during the nitro-sulfuric acid treatment. Such kinds of acidic functional groups are hydrophilic and tend to react with alkalis. Thus, it is all those hydrophilic groups that cause ACM to be soluble in alkali aqueous solution. During the oxidation, the links between adjacent graphitic microcrystallines in NC was forcibly broken. However, the graphene sheets composed of small hexagonal carbon rings are too stable to be destruction. As the concentration increase of ACM, gel was formed by the molecular movement and graft. In this paper, ACM-based nano-spheres were synthesized in aqueous solution. This, from another point of view, could demonstrate ACM could disperse in water in nano size with the help of hydrophilic functional groups.ACM shows well thermosetting property during heat treatment. This is because the side chain of NC were oxidized, nitrified or sulfonated during the ACM preparation, which reduced the thermoplasticity of material. In this work, we report the preparation of well-controlled ACM-based spheres by solvent evaporation method with polydimethylsiloxane as the continuous phase. The graphitized microspheres were then tested as anode material and showed satisfactory electrochemical behaviors with large capacity (340mAh/g), high initial efficiency (90%), and good rate capability.Artificial graphite powder was coated by ACM in aqueous solutions. Results show that surface defects and edge sites of original graphite were uniformly covered by ACM coating layer after modification, while the overall characteristics of graphite were not severely changed. After modification, the bulk density of material increased while its surface area decreased. Electrochemical measurements were then carried out to evaluate the anode performances of samples in lithium-ion batteries. The composite showed higher initial efficiency, lower inreversible capacitance, and better cyclic performance than raw artificial graphite.As a special precursor with small particle size, plenty of functional groups and widened d002 simultaneously, ACM guarantees subsequent ACM-based activated carbons (AACs) with high specific surface area as well as well-developed mesoporous structure after KOH activation. The modification of pore structure or achieved by controlling the activation conditions including KOH/ACM weight ratio, activation temperature and maintain time. In electrochemical measuraments, all AAC samples exhibited high performances as electrode materials for electric double-layer capacitors.