Graphite deposit types , their origin , and economic signi fi cance (original) (raw)
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Carbon in its single layer atomic morphology has exceptional thermal, optical, electronic and mechanical properties, which may form the basis for several functional products and enhanced technologies that go from electricity storage to polymer nanocomposites of so far unsurpassed characteristics. Due to the high cost, however, the current global production of graphene does not exceed 120 tonnes. New chemical and physical methods to exfoliate graphite, however, were recently engineered and commercialized, which open the route to massive adoption of graphene as the ''enabler'' of numerous important technologies, including enhanced electricity storage. This feature article presents an updated, critical overview that will be useful to nanochemistry and nanotechnology research practitioners and to entrepreneurs in advanced materials.
Graphene The Carbon-based 'Wonder Material'
What is a billion times thinner than a piece of paper, stronger than a bullet proof vest yet lighter than a feather, and proof that the smallest things can sometimes be the most powerful? The answer is graphene. Since its recent discovery in 2004, graphene has been a compelling topic in the field of chemistry and science research. Graphene continues to amaze scientists and researchers of the properties the material exhibits. It seems like not a week goes by without a new scientific study being published, or new articles written stating its potential applications. Graphene may be the most remarkable thing ever discovered but what is it really for?
Journal of materials science, 2002
Graphite is reviewed in terms of its physics and chemistry, with particular attention on its physical properties, intercalation compounds, exfoliated form, activated form, fibers and oxidation protection.
Innovative Graphene Technologies: Developments & Characterisation, Volume 1
Graphene is a single-layer sheet of sp 2 hybridised carbon atoms and has attracted tremendous attention and research interest since its discovery in 2004, owing to its exceptional electronic, optical, magnetic, thermal and mechanical properties. This unique material has a single layer of carbon atoms closely packed into honeycomb two-dimensional (2D) lattices. Graphene can be manufactured by exfoliation from graphite, by the epitaxial growth in silicon carbide and by the epitaxial growth on metals. The original methods of preparation of graphene by peeling graphite or vaporising SiC suffered from an inherent lack of control and were not scalable and they have been replaced almost universally by methods to grow controlled epitaxial graphene on different substrates.
Recycling of Graphite Waste into High Quality Graphene Products
2018
Graphite is a stack of carbon layers where carbon atoms form hexagons in a honeycomb structure. Graphene on the other hand is a single atom thick layer which offers unique physical, chemical and biological properties compared to graphite. Recycling graphite waste and converting it into graphene may offer many economic, environmental and health benefits, and may also be used in many applications. Graphite has been used widely in iron-steel, chemical, and nuclear industries for electrical, mechanical and other applications (e.g., metallurgy, pencil, coatings, lubricants and paint). Especially, most of the anode materials of batteries for car, truck and other vehicles and electronic devices are made of graphite. After two to four years of lifetime, these anode materials are either landfilled or sent to an incineration furnace. The major goal of this study is to produce recycled graphene from graphite waste. The objectives of this study are to recycle graphite from batteries and other s...
Graphene: A New Generation Smart Material
2013
The graphene is the two dimensional carbon sheets made from the ghiphite. The π-conjugation in graphene shows extraordinary thermal, mechanical and electrical properties. It is the materials of new generation in the scope of scientific, industrial interest. In present review, the basics of graphene are highlighted with reference to its advantages with respect to other carbon based materials. The preparation of graphene at different methods is summarized with their comparative advantages. The emerging properties of the graphene are narrated with other materials of comparative behavior. The possible applications of graphene and related materials are established with reference to their structural properties.
Georgakilas/Functionalization Of Graphene, 2014
Carbon takes its name from the latin word carbo meaning charcoal. This element is unique in that its unique electronic structure allows for hybridization to build up sp 3 , sp 2 , and sp networks and, hence, to form more known stable allotropes than any other element. The most common allotropic form of carbon is graphite which is an abundant natural mineral and together with diamond has been known since antiquity. Graphite consists of sp 2 hybridized carbon atomic layers which are stacked together by weak van der Waals forces. The single layers of carbon atoms tightly packed into a two-dimensional (2D) honeycomb crystal lattice is called graphene. This name was introduced by Boehm, Setton, and Stumpp in 1994 [1]. Graphite exhibits a remarkable anisotropic behavior with respect to thermal and electrical conductivity. It is highly conductive in the direction parallel to the graphene layers because of the in-plane metallic character, whereas it exhibits poor conductivity in the direction perpendicular to the layers because of the weak van der Waals interactions between them [2]. The carbon atoms in the graphene layer form three σ bonds with neighboring carbon atoms by overlapping of sp 2 orbitals while the remaining p z orbitals overlap to form a band of filled π orbitals-the valence band-and a band of empty π* orbitals-the conduction band-which are responsible for the high in-plane conductivity. The interplanar spacing of graphite amounts to 0.34 nm and is not big enough to host organic molecules/ions or other inorganic species. However several intercalation strategies have been applied to enlarge the interlayer galleries of graphite from 0.34 nm to higher values, which can reach more than 1 nm in some cases, depending on the size of the guest species. Since the first intercalation of potassium in graphite, a plethora of chemical species have been tested to construct what are known as graphite intercalation compounds (GICs). The inserted species are stabilized between the graphene layers through ionic or polar interactions without influencing the graphene structure. Such compounds can be formed not only with lithium, potassium, sodium, and other alkali metals, but also with anions such as nitrate, bisulfate, or halogens.
Not just graphene: The wonderful world of carbon and related nanomaterials
MRS Bulletin, 2015
So, how does one answer the question: "Which carbon material is the best for use in a specifi c component or a device?" Although sp-bonded carbon materials, carbynes, exist, we still do not know how to produce them in large quantities, not just a few atoms in a chain. Linear carbon chains have been seen inside carbon nanotubes but not in bulk quantities. 6 Such carbons do not yet have any engineering applications. This article primarily focuses on sp 2-bonded carbons because of the included case study on supercapacitors, an application that requires high conductivity. 7 The π-electrons in sp 2-bonded carbon materials such as graphene and nanotubes make these materials electrically conductive, and this is a very important property for many applications of carbons. But even if we consider just sp 2 carbon, the variety of carbon forms is astounding: graphene, nanotubes, fullerenes, onion-like carbon (multishell fullerenes), nanohorns, nanocones, rings-and this list goes on. 8 The most common sp 2-bonded carbon materials used commercially are graphite, activated carbon (activated charcoal), carbon black, and carbon fi bers. These materials are abundant and readily available; their use in the electrodes of batteries and supercapacitors make our computers and cell phones work. But what do we really need for a specifi c application? Graphene can be considered to be a basic element, from which a graphite crystal can be