Graphene super strong but not graphite?

In summary, graphene is incredibly strong due to its single-layer structure, but when stacked on top of each other in graphite, the layers can easily slide apart. This makes graphite a good dry lubricant, as the layers can glide over each other. However, when exposed to strain along the graphene planes, the overall strength of graphite is weakened, as the layers are only strong in one plane. The lubrication properties of graphite are also due to the presence of fluids between the layers, such as air and water, rather than just weak inter-layer bonds. In vacuum, graphite is not an effective lubricant. While a pure graphite crystal pulled along its planes would be very strong, typical graphite is not as pure and has a spaghetti-ball like structure
  • #1
TriKri
72
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How does it come that graphene is so strong, but not graphite? Graphite is basically just many graphene sheets stacked on top of each other so it should super duper strong.
 
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  • #2
Ah, but you should consider how they are stacked on top of each other. Graphite "slides" apart in different sheets.
 
  • #3
The reason graphite is used as a dry lubricant is because the layers slip past each other easily.

Yes, they are strong in one plane, but very weak across planes.
 
  • #4
Okay, so they slide on top of each other, but that is only when the graphite crystal is exposed to shearing, right, so what about when the crystal is exposed to strain along the graphene planes? Then the force the graphite would be able to take would still be the sum of the forces the graphene layers can take, which would still be super much? Or am I thinking wrong here?
 
  • #5
By the way, the lubrication properties of graphite is due to the presence of fluids between the layers, such as air and water, which are adsorbed naturally, from the environment, and not solely do to the weak inter-layer bounds. In vacuum, graphite becomes a poor lubricant. In theory, if you pulled a pure graphite crystal along the direction of its planes, it would be very strong. But you would have to have a very pure crystal stack, all lined up, and be pulling at just the right direction, and pulling all layers equally. Typical graphite, like in a pencil, or more like a spaghetti-ball of layers/fragments.
 
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1. What is the difference between graphene and graphite?

Graphene is a single layer of carbon atoms arranged in a hexagonal lattice, while graphite is composed of multiple layers of graphene stacked on top of each other.

2. Why is graphene stronger than graphite?

Graphene's strength comes from its 2-dimensional structure, which allows for stronger intra-molecular bonds between carbon atoms. Graphite, on the other hand, has weaker inter-molecular bonds between its layers.

3. Can graphene be used as a replacement for graphite in all applications?

No, graphene and graphite have different properties and uses. While graphene is extremely strong and conductive, graphite is more flexible and has better lubrication properties.

4. Is graphene more expensive than graphite?

Yes, graphene is more expensive to produce than graphite due to the complexity of its production process and the need for high-quality graphene to achieve its desired properties.

5. What are some potential applications of graphene compared to graphite?

Graphene has potential applications in various industries, including electronics, aerospace, and biomedicine, due to its unique properties such as high strength, conductivity, and flexibility. Graphite, on the other hand, is commonly used in pencils, batteries, and lubricants.

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