Graphene vs. Graphite: Which one’s more Useful?

Graphene is a single isolated layer of graphite. It has a 2D arrangement and the carbon atoms are bonded in a hexagonal (honeycomb) structure in a continuous sheet. On the other hand, graphite is a naturally occurring mineral. Its structure is made up of numerous graphene sheets stacked over each other through pi bonds.

Graphene vs Graphite

Graphene: A wonder material

Graphene is a synthetic allotrope of carbon. It was first made in 2004 by Professor Andre Geim and Professor Kostya Novoselov at Manchester University. They were awarded a noble prize in physics for this tremendous work. Graphene has unique properties such as high tensile strength, high conductivity, the vast surface area holding strength, and optical transparency making it a suitable material in advanced applications.

It is called a wonder material for some reasons:

• Graphene has the best conductivity shown by any existing material. This is due to a pi layer of electrons all over its 2-D structure.
• It is carbon-based (non-metal), which makes it more usable than even metals.
• Its unique molecular compositions could make it the smallest and most useful filter i.e. for filtering seawater to get drinkable water. This could save millions of lives around the world.
• Graphene is one of the lightest weighed materials. It is in fact, 1000 times lighter than paper.
• The strength has obviously no questions i.e. it is 300 times stronger than steel and 40 times stronger than diamond.
• The flexibility of graphene is also tremendous.
• It is one of the most promising nanomaterials being the thinnest, strongest, and optically transparent than all other materials. It transmits more than 90% of the light it gets.
• Biomedical sensors can use this to detect disease causing agents such as viruses and bacteria, etc.
• It is also a perfect barrier, as not even helium gas can pass through it.
• Other than all other marvelous properties, it is also chemically inert, making it even more useful.

Graphite

Graphite has layers of graphene interconnected through weak Van der Waal’s forces. The carbon atoms are present in hexagons and these hexagons are connected sidewise to form a honeycomb structure. The only difference between the structure of graphene and graphite is that graphene is 2-D while, graphite is a 3-D structure.

Each carbon atom forms 3 strong covalent bonds with neighboring 3 carbon atoms. The 4th bond is present in graphite, which is made across sheets. This bond is made by p-orbitals so, a pi-bond creates a delocalized cloud of electrons. These layers are connected through weak forces so, it is slippery and the layers may slide over each other.

Some significant properties of graphite are explained below:

1. Thermodynamically stable

Strong covalent bonds are present throughout the layers in the graphite. Also, delocalized pi bonds are present between the layers. This makes it highly stable. It sublimes at about 3600°C.

2. Soft and malleable

Graphite is easily scratchable and moldable. This is due to the presence of weak forces between the layers. When graphite is pressed or hammered, its layers slide over each other. Therefore, it is used in lubricants and pencils.

3. Good conductors

It is a good conductor of electricity when voltage is applied parallel to hexagonal layers. Its conductivity is in the order of ∼10⁴ S cm^-1. That is why it is vastly used in electrodes and conducting materials. However, it is not as good in conduction when current is to be passed between the layers i.e. perpendicular to the layers.

Related links

• Crystal structure and types
• Paramagnetic vs. diamagnetic substances
• Properties of matter

Uses of Graphene vs Graphite

Graphene can be used in many and many industries. In fact, right now it may be the most important material being used in industries. Some of such applications are followed as:

• Microelectronic circuits as good conductors and sensors.
• Polymer-based solar cells.
• Batteries to enhance cathode conductor performance.
• Supercapacitors due to their energy storage capacity.
• Anti-tracking devices.
• Touch screens, due to their conductive and transparent requirements.
• Mechanical sensors where minute sensing is to be done.
• Bio-sensors can detect even the smallest of things.
• It is used in composite materials.
• Carbon nanotubes are widely made by using graphene.

Graphite, on the other hand, is used in the following disciplines.

• It is used in batteries because of its coping with lithium ions while charging and discharging.
• In the cores of nuclear reactors, it is used as a moderator.
• Brushes of electronic motors are made up of graphite, due to its low contact dropping properties.
• It is used in lubricants, because of its malleability. It also shows low shear strength under friction force.
• Being resistant to extreme heat, graphite is used in solar panels as a heat shield and thermal insulation.

Key Takeaway(s)

• Graphene has similar properties to that of graphite but in a much enhanced way.
• When compared with graphite, graphene is much more reactive and useful.

Concepts Berg

What is the main difference between graphene and graphite?

The main difference between graphene and graphite is the type of arrangement in their structure. Graphite is a 3D layered structure whereas, graphene is a 2-D, atom-thick layer of the hexagonally arranged layer.

What does graphene-like mean? 

The materials that have thin layered structures are known as graphene-like.

How can we use graphene?

Graphene found several potential applications in electronics, heavy machinery, and defense purposes.

Why is graphene a better conductor than graphite?

Graphene conducts electricity better than graphite because it has delocalized electrons that are free to move across its surface.

Why is graphene so strong compared to graphite?

Graphene sheets are made of giant covalent structures of hexagons of carbon. It is said that only a single square meter sheet that weighs only 3 grams can bear 4 kg of weight.

What is the difference between graphene and pristine graphene?

Pristine graphene is freshly prepared and the purest form of graphene.

Is graphene stronger than tungsten?

Tungsten contains metals atoms that are present in a sequence. They form strong metallic bonds through a sea of electrons in between them. These sheets slide over each other, and therefore, can be deformed. However, graphene is stronger and cannot be deformed easily.

When does graphene become graphite?

When the layered structure of graphite is disturbed through any physical or chemical means, it becomes a single layer sheet called graphene.

References

• Graphite, Graphene, and Their Polymer Nanocomposites edited by Prithu Mukhopadhyay (Society of Plastics Engineers), Rakesh K. Gupta (West Virginia University)