Graphene vs. Graphite: Definition and Structure
Graphene is a single-layer, two-dimensional (2D) allotrope of carbon, consisting of a hexagonal lattice of sp2-bonded carbon atoms arranged in a honeycomb structure. It can be considered as the fundamental building block of graphite, which is a crystalline form of graphene layers stacked together by weak van der Waals forces.
In contrast, graphite is a three-dimensional (3D) crystalline allotrope of carbon, composed of multiple layers of graphene sheets held together by van der Waals forces. The interlayer spacing in graphite is approximately 3.34 Å.
Properties
Graphene exhibits remarkable properties due to its unique structure. It has high electrical conductivity (with an electron mobility of 10,000 cm2/(V·s)), excellent thermal conductivity (around 5,000 W/(m·K)), and exceptional mechanical strength (with Young’s modulus of 1 TPa and tensile strength of 130 GPa). Graphene also has a large specific surface area of 2,630 m2/g.
In contrast, graphite has anisotropic properties due to the difference between in-plane and out-of-plane bonding. While it has high electrical and thermal conductivity along the basal plane, these properties are significantly lower in the perpendicular direction. Graphite is also less mechanically robust compared to graphene.
Synthesis
Graphene can be synthesized through various methods, including mechanical exfoliation (e.g., the Scotch tape method), chemical vapor deposition (CVD), and chemical exfoliation (e.g., the Hummers’ method). CVD is a widely used method for producing high-quality graphene on a large scale, but it requires high temperatures and specialized equipment.
Graphite, on the other hand, is naturally abundant and can be obtained from mining. However, to obtain graphene from graphite, exfoliation techniques such as mechanical cleavage, liquid-phase exfoliation, or electrochemical exfoliation are required.
Applications
Graphene’s exceptional properties make it promising for various applications, including electronics (e.g., transistors, sensors, transparent electrodes), energy storage (e.g., lithium-ion batteries, supercapacitors), composites (e.g., for enhancing mechanical and electrical properties), and biomedical applications (e.g., drug delivery, biosensors).
Graphite has been widely used in traditional applications such as pencils, lubricants, and refractories. It is also used in electrodes for batteries and fuel cells, as well as in composites for enhancing electrical and thermal conductivity.
Recent Innovations
Recent innovations in graphene synthesis include the development of scalable methods for producing high-quality graphene, such as roll-to-roll CVD and electrochemical exfoliation techniques. Additionally, research is ongoing to explore the potential of graphene-based composites and hybrid materials for various applications, such as energy storage, catalysis, and environmental remediation.
In the case of graphite, recent efforts have focused on developing efficient exfoliation techniques to produce graphene nanoplatelets or few-layer graphene, as well as exploring the potential of graphite-based composites for electromagnetic interference shielding and thermal management applications.
Application Cases
Product/Project | Technical Outcomes | Application Scenarios |
---|---|---|
Graphene Powder Beijing Yanshan Petrochemical Co., Ltd. | Significantly reduces electrode internal resistance and improves battery stability at any current rates. | Conductive composite materials, anti-corrosion coatings, heat dissipation composite materials, lithium-ion batteries. |
Graphene Sheet BAE Systems Plc | Allows carbon atoms to settle on the surface of the liquid and coalesce to form the graphene sheet. | High-quality graphene production for various industrial applications. |
Bulk Graphene Production Apparatus Black Swan Graphene, Inc. | Efficient delamination of bulk laminar material to produce graphene. | Large-scale graphene production for industrial applications. |
Patterned Graphene Massachusetts Institute of Technology | Facilitates graphene growth on the exposed surface of the growth substrate. | Advanced electronics and sensor applications. |
Graphene Sheet Kyushu University | Produces high-quality, high mobility, and large area graphene sheets. | Research and development in nanotechnology and material science. |
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