Graphene-based nanocoating to convert heat into electrical energy
Researchers found that the use of highly conductive graphene layers for thermoelectric energy capture is a promising approach to convert heat into electrical energy, gaining new insights into how to best utilise the conductivity in graphene-based nanomaterials.
Researchers from the Materials Physics group at the University of Sussex publishes their work on thermoelectric capture, using highly conductive graphene sheets, which might just remove those barriers and offer a cheap, sustainable technology for heat capture and conversion as well as demonstrating new understanding of how conductivity in graphene-based nanomaterials is best exploited.
The group has developed a printable graphene-based coating to exploit thermoelectric capture, enabling the recycling of waste heat into electrical energy. The coating is printed into a patch or a pad which can then be applied to the heating surface. Where the ambient environment is cooler, electrons travel away from the heat source and move into the cold, generating electrical activity which is conducted through the nanosheets. This thermoelectric transport system could be connected to an external power bank, to charge a battery, or could directly power another device.
The study led the group to conclude that, where densely packed layers of nanosheets might have been expected to correspond to improved electrical transport, fewer layers worked better despite the greater number of inter-nanosheet junctions. “The results were surprising. This is the first time we’ve examined nanomaterial networks specifically from the point of view of how their structure and properties influence electrical conductivity,” said Keiran Clifford, doctoral researcher with the group and first author of the paper. “Graphene is well-known to be highly conductive, but the idea that films of many small nanosheets with lots of junctions would be more efficient than bulkier, multi-layered systems is new and opens the door to many applications,” added Clifford.
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Thermoelectric materials which can convert heat to electrical energy already exist but are typically made from expensive synthetic crystals which are challenging to integrate into varied structures. Potentially we have an easy and highly efficient way to optimize thermoelectric capture in vehicles, devices, homes – even people! We are not currently aware of any other commercially viable, scalable, heat capture coatings, which can be printed for direct coating or as flexible layer,” said Sean Ogilvie, research fellow with Materials Physics and corresponding author of the paper.
Work on the inks and coatings is advancing and the group have demonstrated pilot-scale production, where a sample is brought into contact with a heat source and a voltage induced, but there is still significant development required to integrate the coatings with the different types of patches, pads or panels suitable for use with devices.
If you are interested in more information about the research: it has been published in Carbon.
