Intercalation of Li to a Few Layers of Graphenes
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The purpose of this work is to study the electric properties of graphite and the synthesis of a few layers graphite intercalation compounds (GIC). First, intercalation of Li between graphite layers was done by soaking the substrates into a 20 ml n-butyllithium solution. Second, intercalation of FeCl3 into the graphite was done by heating FeCl3 powder and graphite in the quartz tube. For Li intercalation, the appearance of an extra Bragg reflection at 23.7º indicates that Li atoms were intercalated between the graphene sheets in the specimen we grew. For FeCl3 intercalation, the (00l) Bragg reflection was caused by the FeCl3-GIC. Probably Iron Chloride was intercalated in graphite. In the Raman spectra of graphite and FeCl3-GIC, the G, D and 2D peaks were confirmed. Additional peaks only in the specimen of FeCl3-GIC were observed at 1605 cm-1 and 3415 cm-1. It is speculated that the peak is related to the intercalation of FeCl3 into the graphite.Keywords:
Graphite intercalation compound
The changes resulting from the compression of graphite-CrO a intercalation compounds are demonstrated in the TG curves. In comparison with the samples examined in the form of a flake bed, the compacted compounds begin to decompose at lower temperatures and their weight loss is higher, particularly above 220 ~ To explain the obtained results, the pressure-induced changes in the structures and the activities of the compounds are considered in relation to the method of intercalation, the concentration of the intercalant and the extent of exfoliation, Intercalation compounds of graphite (GIC) are formed in reactions between graphite and certain elements or molecules. The alternating sequence of n hexagonal graphite layers and a monolayer of foreign species, called the stage number, is a characteristic feature of their structure. The insertion of the guest species between the host graphite interspaces results in the creation of new, interesting properties. The structural, electrical and thermal changes effected by intercalation have been the most intensivelY explored [1, 2]. The thermal studies have often related to the exfoliation phenomenon caused by the thermal decomposition of GIC [3-9], Above a critical temperature, the intercalant escapes from the graphite interspaces, as demonstrated by a large expansion of the sample along the c-direction and consequently a very swollen product is formed. The process ofdeintercalation can be observed in the TG curves if the released intercalant itself undergoes thermal decomposition and/or participates in a secondary reaction with the graphite carbons. The occurrence of both processes has been reported for graphite-CrO 3 intercalation compounds (GIC-CrO3's) [10-12]. When flakes of GIC-CrO3's are heated above 220 ~ lower oxides of chromium are formed, not only due to the thermal decomposition of the intercalated CrO3, but also as a result of the reduction of CrO 3 by the graphite carbons. Consequently, a two-phase mixture of these oxides and the depleted
Exfoliation joint
Graphite intercalation compound
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A new graphite intercalation compound (GIC), n-octylammonium tetrachlorofeffate(Ⅲ)-graphite, has been derived from well-known ferric chloride graphite intercalation compound. X-ray diffration study shows that the basal spacing of this new GIC is 20.8 Å. In order to investigate the local geometry around the iron atom in the graphite layers, X-ray absorption spectroscopy experiments were performed. The first discharge capacity of its exfoliated form is found to be 862 mAh/g, which is more than double the value of pristine graphite (384 mAh/g). Such a drastic increase implies that the exfoliated graphite is a promising electrode material.
Exfoliation joint
Carbon fibers
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Graphite oxide
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Cr_2O_3-graphite intercalation compounds (GICs)were prepared using graphite and CrO_3 as raw materials by vacuum heat-treatment.The stage 5 GICs was formed after heat treatment at 1400℃,and it was examined and characterized by X-ray diffraction (XRD).The XRD analysis of intercalation compounds indicated that a number of non-carbon reactant (atom,molecule,ion or groups)could intercalate the layers of graphite with reticulated layer structure physically.Consequently the layered structure of graphite changed and thus new physical and chemical properties were obtained.X-ray photoelectron spectroscopy (XPS)suggested that the compound intercalated into graphite should contain Cr~(?)compound.
Graphite intercalation compound
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The purpose of this work is to study the electric properties of graphite and the synthesis of a few layers graphite intercalation compounds (GIC). First, intercalation of Li between graphite layers was done by soaking the substrates into a 20 ml n-butyllithium solution. Second, intercalation of FeCl3 into the graphite was done by heating FeCl3 powder and graphite in the quartz tube. For Li intercalation, the appearance of an extra Bragg reflection at 23.7º indicates that Li atoms were intercalated between the graphene sheets in the specimen we grew. For FeCl3 intercalation, the (00l) Bragg reflection was caused by the FeCl3-GIC. Probably Iron Chloride was intercalated in graphite. In the Raman spectra of graphite and FeCl3-GIC, the G, D and 2D peaks were confirmed. Additional peaks only in the specimen of FeCl3-GIC were observed at 1605 cm-1 and 3415 cm-1. It is speculated that the peak is related to the intercalation of FeCl3 into the graphite.
Graphite intercalation compound
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According to X-ray power diffraction,the patterns of graphite which was treated by different methods are obtained.These X-ray diffraction patterns show that the layers of graphite are inserted by other matters by physical and chemical methods.This kind of matter is called graphite complex intercalation compound which widen the application of the graphite complex intercalation compound.
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The results presented in this paper demonstrate that the process of intercalation; i.e., the formation of chemical compounds via insertion of atomic or molecular species in the van der Waals gap between planes of lamellar solids can substantially improve the intrinsic lubricating properties of solids. Using graphite as a model host compound, various transition metals and metal chlorides intercalated into graphite were formulated into solid film lubricants and their lubricating properties determined in a laboratory wear test device. Comparisons of endurance life and load-carrying capacity are made relative to molybdenum disulfide and unintercalated graphite. Graphite/19.8 wt. percent CoCl2 was found to exhibit over a fivefold increase in endurance life while graphite/19.3 wt. percent NiCl2 provided a greater than twofold increase in load-carrying capacity relative to graphite and was equivalent to MoS2. The degree of improvement in endurance life was found to be dependent on the concentration of intercalant in graphite and the resulting increase in interlayer carbon spacing due to intercalation. A total of 23 different intercalate compounds were investigated at various concentration levels.
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