Indian Institute of Technology Madras (IITM) recently stated that its researchers have shown a simple route to producing graphene platelets from graphite.
“They have found that when graphite is suspended in an appropriate fluid and subjected to intense shearing force of machining, the layers of graphite separate into graphene platelets,” a statement from IITM said.
“Superior quality graphene is commonly prepared by the exfoliation method,” said Sathyan Subbiah, Associate Professor, Department of Mechanical Engineering at IITM.
Subbiah looked at exfoliation from an unconventional angle. “Graphite is a lubricant because it is made of layers of carbon that slide over one another. The lubricating action itself would shear the layers off, and cause separation of the 2D graphene sheets,” he was quoted as saying in the statement.
The IITM researchers suspended graphite in a lubricant liquid containing sodium cholate to prevent the graphite particles from clumping together and subjected the suspension to machining of mild steel using oscillations of a carbide tool.
As Subbiah had expected, the oscillations trapped the graphite to produce graphene flakes as a byproduct of the lubricant with thicknesses in the range of a few nanometers.
The IITM team’s experiments showed that increasing the time of machining induces defects and disorders in the layers.
“We are now focusing on controlling the stresses and machining parameters to produce defect-free few-layer graphene,” said Subbiah on future directions of his research.