Scientists used to make graphene-based membranes in small batches in a laboratory. But a new breakthrough at MIT enables researchers to spool out long rolls of high-quality graphene. The continuous manufacturing process can produce five centimeters of high-quality graphene per minute. The longest run was nearly four hours, and it generated around 10 meters of continuous graphene.
MIT is calling the development “the first demonstration of an industrial, scalable method for manufacturing high-quality graphene that is tailored for use in membranes that filter a variety of molecules.” These membranes could be utilized in biological separation or desalination, for example. The researchers drew from the common industrial roll-to-roll approach blended with chemical vapor deposition, a common graphene-fabrication technique.
Their system is comprised of two spools linked by a conveyor belt, which runs through a furnace. According to MIT, here’s how it works: “The first spool unfurls a long strip of copper foil, less than one centimeter wide. When it enters the furnace, the foil is fed through first one tube and then another, in a ‘split-zone’ design. While the foil rolls through the first tube, it heats up to a certain ideal temperature, at which point it is ready to roll through the second tube, where the scientists pump in a specified ratio of methane and hydrogen gas, which are deposited onto the heated foil to produce graphene.”
MIT associate professor of mechanical engineering John Hart said, “In the end-to-end process, we would need to integrate more operations into the manufacturing line. For now, we’ve demonstrated that this process can be scaled up, and we hope this increases confidence and interest in graphene-based membrane technologies, and provides a pathway to commercialization.”
The journal Applied Materials and Interfaces recently published the work; scientists from Vanderbilt University, the California Institute of Technology and the National University of Singapore contributed.