What if there was a low-power energy source, like a watch battery, that never needed replacing? Paul Thibado may have found that source in graphene, and he and others are working to share this discovery with Arkansas and the world.

Graphene, a nanomaterial comprised of a single layer of carbon atoms arranged in a honeycomb lattice structure, has been explored for a variety of uses in recent years, from water filtration to electronics and wearable technology. But Thibado, a professor of physics at the University of Arkansas, is working to harness its potential to produce energy – and not just any type of energy…clean, limitless energy, like wind and solar.

The possibilities for its use are nearly as endless as the energy it supplies, resulting in an exciting new way to think about powering technology. And the hub for its development is right here in the Natural State.

Good Vibrations

Thibado and his colleagues were studying the motion of graphene by laying sheets of the one-atom-thick material across a copper grid that acted as a scaffold when they observed something unexpected: as the planes of graphene absorbed energy from the surrounding environment, they moved like waves on the surface of the ocean.

This discovery became the impetus for creating a graphene circuit element, where a negatively charged sheet of graphene is suspended above a metal electrode. As the graphene flips up, it induces a positive charge in the top electrode, and when it flips down, the charge flows out of the circuit, creating an alternating current.

Following this discovery, Thibado’s team set out to “miniaturize” the energy harvesting technology and reproduce the essential components of the original experiment on a silicon chip. His current efforts in the development of this technology are focused on building a device he calls a Graphene Energy Harvester (or GEH).

Harvesting Energy

With the support of a $900,000 grant from the WoodNext Foundation, Thibado is now making graphene energy harvesting a reality. Working with researchers from the University of Michigan, Thibado’s lab reported the first use of ultra-low power temperature sensors using graphene-based solar cells. This test was the first hurdle in developing autonomous sensor systems that draw power from multiple sources in the environment — solar, thermal, acoustic, kinetic, nonlinear and ambient radiation.

The end goal is development of multi-modal sensors (incorporating more than one of the above power sources) using the energy-harvesting capability of graphene that can last decades and helps realize the “Internet of Things,” in which smart technology is woven into the fabric of daily life.

The researchers needed to solve two problems:

1. Reduce sensor power demand to nanowatts, a billionth of a watt, as opposed to the current standard, which is measured in microwatts (a millionth of a watt) and
2. Power the sensor using energy harvested from the local environment.

“Power has to be drawn from the local environment,” Thibado explained, “so it’s self-powered and autonomous, and it has to have an extremely long operational lifetime to dramatically reduce the total cost of ownership. So set it and forget it.”

He added that “We anticipate building devices that harvest multiple sources of energy within that device.”

By making them “multi-modal,” intermittent shortages in solar power can be augmented with additional thermal or non-linear power, whatever the case may be.

Thibado foresees the sensors being used in areas and fields where sensors would be useful but the need to replace batteries would make them labor and cost prohibitive. This could include use in things like agricultural climate monitoring, tracking livestock, wearable fitness monitoring, building alarm systems, predictive maintenance and a wide range of other applications.

The Next Wave

NTS Innovations, a company specializing in nanotechnology, owns the exclusive license to develop graphene energy harvesters into commercial products. The company has provided funding for patenting, creating business plans, finding business partners and customer discovery.

Their role over the course of the WoodNext grant is to engage with customers on acceptance criteria, such as the minimum power levels needed for inclusion in products. Currently, more than 60 parties have expressed interest in testing the technology and working with Thibado and his colleagues to integrate it into their applications.