Graphene Composites

Chartarrayawadee, W., Moulton, S. E., Li, D., Too, C. 0., and Wallace, G. G. [2012]. Novel composite graphene/platinum electrocatal3dic electrodes prepared by electrophoretic deposition from colloidal solutions, Electrochim. Acta, 60, pp. 213-223. 

Akin to CNT-based composites, graphene has also been used for making composites with novel properties due to its reasonable mechanical, thermal, electrical properties and large smface area [26,327-330]. 

For example, the relationship between pseudocapacitance and heat treatment temperature of nickel oxide was investigated using XRD, x-ray absorption spectroscopy, and CV. These techniques can provide important information about structure arrangements and the electrochemical properties of nickel oxide at various heat treatment temperatures. Similar studies were performed on composites (graphene-polyaniline, Mn02-mesoporous carbon) [30,31]. XRD can reveal material structures revealing the relationship of electrochemical properties and the effects of certain chemical or physical alterations. 

Keywords Clay Composites Graphene Nanocomposites Rubbers Two-dimensional fillers... 

In other pursuits, the utilisation/fabrication of doped graphene structures (or the fabrication of novel three-dimensional hybrid/composite graphene materials) has been reported to be useful due to the significantly altered electrochemical properties, where modification of the graphene can result in improved conduction or electronic properties (DOS), increased disorder and/or edge plane accessibility [41, 42]. 

Although in this work microfibers textile, not nanofiber, was used as the substrate, we consider that instead of mlcrofibers, CNFs and conductive polymer nanofibers can also be used as the electrode substrate which will even increase the conductivity. Wei and co-workers have successfully obtained graphene nanosheets (GNS) incorporated with RUO2 and Ti02 nanoparticles (Fig. 7.7). If these composite graphene nanosheets coated on porous nanofibers, excellent supercapacitor electrode can be expected. 

For more efficient utilization of MOFs sorbents, several hybrid systems based on MOFs with other solid sorbents have been investigated in the literature. The objective of having hybrid materials is to utilize the synergism between the two sorbents and therefore ultimately improve the overall performance in C02 separation. Moreover, sorbents such as activated carbons, graphenes, and CNTs provide the added feature of high surface area and easily functionalized sites which contribute to the tuning of the final properties of the composite... 

The N-doped carbons with a nanotube backbone combine a moderate presence of micropores with the extraordinary effect of nitrogen that gives pseudocapacitance phenomena. The capacitance of the PAN/CNts composite (ca. 100 F/g) definitively exceeds the capacitance of the single components (5-20 F/g). The nitrogen functionalities, with electron donor properties, incorporated into the graphene rings have a great importance in the exceptional capacitance behavior. 

Figure 5. Composition dependence of the average graphene interlayer spacing during the lithium intercalation and de-intercalation.

Although the electrical properties of GO are significantly inferior to pristine graphene, the presence of the functional groups on the flakes can be a considerable advantage when considering composites [6]. 

H. Kim, C.W. Macosko, Processing-property relationships of polycarbonate/graphene composites, Polymer, 50 (2009) 3797-3809. 

U. Khan, P. May, A. O Neill, J.N. Coleman, Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane, Carbon, 48 (2010) 4035-4041. 

Nanocarbon structures such as fullerenes, carbon nanotubes and graphene, are characterized by their weak interphase interaction with host matrices (polymer, ceramic, metals) when fabricating composites [99,100]. In addition to their characteristic high surface area and high chemical inertness, this fact turns these carbon nanostructures into materials that are very difficult to disperse in a given matrix. However, uniform dispersion and improved nanotube/matrix interactions are necessary to increase the mechanical, physical and chemical properties as well as biocompatibility of the composites [101,102]. 

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