A research team at the National University of Singapore (NUS) has developed a way of producing graphene that uses 50 times less solvent than conventional methods.
Conducted in collaboration with Fudan University, China and published in Nature Communications, the new technique is said to address the big challenge in efficiently processing graphene on a large-scale, and could lead to a sustainable synthesis of the material.
Graphene is a highly desirable material due to its ultra strong, flexible and lightweight qualities.
According to The Engineer, the conventional method of graphene production uses sound energy to "exfoliate" graphene layers from graphite, and then disperse the layers in large amounts of organic solvent.
But because insufficient solvent causes the graphene layers to reattach themselves back into graphite, yielding one kilogram of graphene currently requires at least one tonne of organic solvent, making the method costly and environmentally unfriendly.
However, the NUS researchers' development is claimed to use up to 50 times less solvent. This is apparently done by exfoliating pre-treated graphite under a highly alkaline condition to trigger flocculation, which means the graphene layers cluster together to form graphene slurry without having to increase the volume of solvent.
The resulting graphene slurry can then be separated into monolayers when required or stored. It is further claimed that the slurry can be used to directly 3D-print conductive graphene aerogel, an ultra-lightweight sponge-like material that can be used to remove oil spill in the sea, for example.
"We have successfully demonstrated a unique exfoliation strategy for preparing high quality graphene and its composites," said Prof Loh Kian Ping from the Department of Chemistry at the National University of Singapore Faculty of Science.
"Our technique, which produces a high yield of crystalline graphene in the form of a concentrated slurry with a significantly smaller volume of solvent, is an attractive solution for industries to carry out large scale synthesis of this promising material in a cost-effective and sustainable manner."
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