Nano Graphite Powder and Its Applications
nano graphite powder is an advanced processing technology material with average particle size between 40-500 nm, purity above 99.5% and wide range of applications. This powder can be used in lubricant to improve anti-friction, corrosion resistance and increase thermal and electrical conductivity; thread sealant pastes for long life sealing performance even under severe temperature and pressure conditions; as conductive additive in battery applications (alkaline, li-ion and lead acid) to increase thermal and electrical conductivity; and many other applications.
Preparation and Exfoliation Techniques: The most important criterion for graphite exfoliation is the good matching of solvent surface energies with graphene. The best solvents for graphene exfoliation are those with surface energy close to the graphene surface energy [114-116].
Ultrasound-Assisted Exfoliation: In the present study, low-power ultrasound irradiation (Branson 1510E-MT bath sonicator, nominal maximum power: 80 W) in N-methyl-pyrrolidone (NMP) or sodium cholate aqueous solution was used to prepare highly exfoliated graphene monolayer and multilayer flakes. These flakes were characterized by wide field and close-up transmission electron microscope (TEM) images, as shown in Fig. 7.2.
Graphene Reducer and Stabilization Agents: In order to improve graphene synthesis, various biomolecules, microbes, and plant extracts are used as reducing and capping agents for graphene oxide synthesis. These substances include ascorbic acid or vitamin C, nitric acid, diazonium salts BPD and SPD, sodium hydroxide (NaOH), hydrogen peroxide (H2O2), acetone, and chloroform cyclohexanone.
Hummer’s Method is an effective and safe method for preparing graphene oxide from graphite. This method was developed in 1958 and involves the oxidation of pristine graphite with an oxidizing agent such as KMnO4 to a solid state graphite oxide. This process is completed within a few hours and requires minimal chemical intervention.