Jul 19, 2011 12:47 GMT  ·  By
Using a small sheet of the graphene coating (dark blue patch) connected to gold contacts, the RPI team demonstrated the creation of 85 nanowatts of power
   Using a small sheet of the graphene coating (dark blue patch) connected to gold contacts, the RPI team demonstrated the creation of 85 nanowatts of power

There appears to be no limit to the amount of things graphene can do. The 2D carbon compound was recently demonstrated to be able to harvest energy from flowing water, producing small amounts of electricity. This is an applications that not even its creators envisioned.

Though it's unlikely that graphene-based systems will ever develop to the point where large-scale applications become possible, the new technique could be used to develop self-powered microsensors.

These devices could have a host of applications, such as for example prospecting for natural gas and oil inside environments where providing energy for them from external sources is impossible. The approach that enables all these uses was developed at the Rensselaer Polytechnic Institute (RPI).

Professor Nikhil Koratkar was the one who proposed that surfaces be coated with graphene, in order to test whether liquid flowing over them will create electricity. A sheet of the carbon compound measuring just 0.03-by-0.015 millimeters was able to produce 85 nanowatts of power.

If nanosensors using graphene are injected down a water column – such as the ones used by oil and gas prospectors – then they would have enough energy to prospect underground for prolonged periods of time. This could help discover more oil reserves where other methods fail.

The electricity itself is indeed so that the sensors can send their readings back to the surface. “It’s impossible to power these microsensors with conventional batteries, as the sensors are just too small,” Koratkar explains.

“So we created a graphene coating that allows us to capture energy from the movement of water over the sensors,” adds the expert, who is a professor in the departments of Mechanical, Aerospace, and Nuclear Engineering, and Materials Science and Engineering, at the RPI School of Engineering.

“While a similar effect has been observed for carbon nanotubes, this is the first such study with graphene. The energy-harvesting capability of graphene was at least an order of magnitude superior to nanotubes,” he goes on to say.

The expert explains that graphene is more suited for such applications because of its 2D nature. The material can easily be bent, flexed or twisted around any conceivable shape or form, which makes it more valuable than CNT.

“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 goes on to say.

Details of the study appear in a paper entitled “Harvesting Energy from Water Flow over Graphene,” which is published in the July 18 issue of the esteemed scientific journal Nano Letters.