GRAPHENE AND GRAPHENE-BASED NANOCOMPOSITES: SYNTHESIS AND SUPERCAPACITOR APPLICATIONS

Graphene, a single-atomic-thick sheet, consists of sp(2)-bonded carbon atoms in hexagonal lattice and possesses excellent physical and chemical properties such as high surface area, conductivity, mechanical strength and lightweight. The two-dimensional geometry of graphene nanosheets is ideal for many applications especially in electrochemical energy storage. However, the large-scale production of graphene materials is still a bottleneck limiting the development of advanced energy storage devices. The production of graphene oxide is one of the most critical restrictions in term of synthesis of graphene by wet chemical methods. We have demonstrated the synthesis of high quality graphene oxide by simple chemical reactions with less exo-therm involved without emission of toxic gases, which is more favorable than conventional methods for commercialized synthesis of graphene materials (Figure 1.). Meanwhile, pseudo-capacitive materials such as Co3O4 and MnSn(OH)(6) coupled with graphene nanosheets were synthesized by soft chemical methods in order to utilize both advantages from electrical double layer and pseudo-mechanisms. Their electrochemical properties were evaluated and the potential applications used as high performance electrodes for capacitive energy storage were discussed as well.