It resists UV degradation. It fights corrosion. It creates ultra-water-resistant surfaces. And now, researchers say, coatings using the wonder material graphene can harvest energy.
Researchers at Rensselaer Polytechnic Institute in New York and Rice University in Houston have developed a new way to harvest energy from flowing water using a nanoengineered graphene coating.
The new technology produces only small amounts of electricity, so it is not aimed at large-scale electricity production—at least, not yet. Still, it holds immediate promise for self-powered microsensors used in oil exploration, scientists say.
Rensselaer / Koratkar
|The graphene coating, seen as a dark blue patch connected to gold contacts, generated 85 nanowatts of power.|
Potential future applications include self-powered microrobots or microsubmarines and harvesting power from a graphene coating on the underside of a boat.
“It’s impossible to power these microsensors with conventional batteries, as the sensors are just too small. So we created a graphene coating that allows us to capture energy from the movement of water over the sensors,” the study’s lead author, Nikhil Koratkar, told the South Asian news service ANI.
“Harvesting Energy from Water Flow over Graphene,” published recently in the journal Nano Letters, is the first research paper to result from a $1 million grant by the Advanced Energy Consortium—a group that is developing intelligent subsurface micro- and nanosensors that can be injected into oil and gas reservoirs to help improve the recovery of existing and new hydrocarbon resources.
The article describes how the microsensors can potentially be self-powered by covering them with a graphene coating. The sensors can harvest energy as water flows over the coating, the team says.
“We’ll wrap the graphene coating around the sensor, and it will act as a ‘smart skin’ that serves as a nanofluidic power generator,” Koratkar said.
Using a sheet of graphene measuring 0.03 by 0.05 mm, the team was able to generate 85 nanowatts of power. Although this is only a very small amount, Koratkar, says it should be enough to power tiny sensors that could be introduced into water or other fluids and pumped down into a potential oil well.
As the injected water trickles through cracks and crevices in the earth, the devices would be used to detect the presence of hydrocarbons to help uncover hidden pockets of oil and natural gas.
Koratkar’s team also tested the energy harvested from water flowing over a film of carbon nanotubes. However, the energy generation and performance was far inferior to those attained using graphene, he said.
Hydroelectricity is the most widely used form of renewable energy, supplying around 20 percent of the world’s electricity in 2006, which accounted for about 88 percent of electricity from renewable sources.
Spotlight on Graphene Research
The thinnest, strongest material ever made, graphene has been on the front burner of global materials science development since the flake of carbon inspired Nobel Prize-winning research in 2010.
Stronger and stiffer than diamond, yet stretchable like rubber, graphene has been found to conduct heat and conduct electricity as well as copper. It is almost transparent, yet so dense that not even helium can pass through it, experts say. Graphene also allows electrons to flow much faster than silicon, and many experts believe it will soon replace silicon technologies.
Several graphene-related coatings breakthroughs have been announced in recent months, and the European Commission has announced a 10-year, 1 billion euro ($1.45 billion US) research initiative focusing on graphene.