Carbon is the miraculous element that creates life, along with diamonds, graphite, fullerenes, nanotubes, graphene, graphdiyne, and more. Among them, graphite, which we are most familiar with, has become an increasingly important carbon material with the development of science and technology.
Graphite is used for a variety of purposes, but one of the most thriving applications is for anodes for lithium-ion batteries, which are critical to the electric vehicle industry. For example, the average Tesla Model S requires 54kg of graphite.
As the world's demand for carbon-based materials such as graphite increases, such materials will become more and more difficult to obtain, and many scientists have therefore begun to explore more possibilities for making carbon.
A team of researchers has proposed a new type of carbon solid, which they call "amorphous graphite." In their paper published in Physical Review Letters, the researchers describe the de novo synthesis of amorphous graphite. Their research started with a question: Can we make graphite from coal?
Graphitization at high temperature
In chemistry, the process of converting an amorphous turbostratic carbonaceous material into a layered graphitic structure through high temperature heat treatment is called graphitization. What the team is after is Ab initio, which can be understood as "de novo", that is, they hope to find a new route from naturally occurring carbonaceous materials, to synthetic forms of graphite.
In the study, the team showed through molecular dynamics simulations with ab initio calculations and machine learning that pure carbon networks have a distinct, even overwhelming tendency to switch to a layered structure in a critical window of density and temperature, even if Delamination can also occur with random initial configurations.
They discovered a layered material called amorphous graphite that forms at high temperatures of about 3,000 degrees Kelvin. Since this phase is topologically disordered, it differs from graphite itself.
If you look closely at the monolayer planes, that is, amorphous graphene, they are not the perfect hexagonal layers that make up ideal graphene. The new material contains a large number of hexagons, but also pentagons and heptagons.
This ring disorder reduces the conductivity of the new material compared to graphene, but remains high in regions dominated by hexagons.
