Graphene — the Energy Booster for Better Storage

Rob Anstey founded his company Graphenix Development on the premise that graphene-based inks will become the material of choice for next-generation devices that will power everything from wind turbines and solar panel energy storage to electric cars and cell phones.

Graphene is a nanomaterial that consists of a single layer of honeycomb-patterned carbon. The thinnest material known to science, it is lightweight, conducts electricity, and is nontoxic. It is 100 times stronger than steel of the same thickness. In bulk form, the material is known as graphite from which pencils are made.

Since it was first isolated as a separate material in a lab in 2004, graphene has attracted considerable attention because of its remarkable optical, mechanical, thermal and electrical properties in addition to its high surface area, which makes it useful for energy storage.

Graphenix has developed a method called Graphenic Intermediate Dispersion System (GRIDS)TM, which provides an efficient and cost-effective way to prepare and disperse graphene into conductive inks to increase conductivity.

“Currently, our company is built around a simple and inexpensive process through which graphene can be dispersed into a black liquid,” Anstey said. “That liquid can be used as a superconcentrate for conductive inks. In addition, you can use this black liquid as a coating to give you a high-functional ultracapacitor that can store more energy than standard ultracapacitors.”

Incorporating graphene in conductive ink can double its conductivity. But mixing graphene into a liquid-based coating hasn’t been easy or cost effective. That’s because graphene’s neat single layers tend to agglomerate in liquid. The GRIDS method fully mixes the graphene in a solvent-based solution.

Using GRIDS, Graphenix is also working on ways to increase storage capacity in ultracapacitors to replace lead acid batteries altogether, making an ultracap that can store three or four times more energy than the ones produced now. Such advances in ultracaps, which range from the size of a small fingernail to a car battery, could someday power electric and hybrid cars without the use of a battery. The U.S. Army and Navy have funded the company for research development in graphene-based materials.

“If you could charge an electric car in the same time it took to fill up gas, that could pave the way to a better market for electric vehicles, especially if you could charge your car in about four minutes instead of hooking it up overnight for eight hours. However, in the near term ultracapacitors will work with lithium-ion batteries,” Anstey said.

Capacitors are like batteries in that they store and discharge electricity, but they charge and discharge power much faster without reducing their operational life. (Conversely, rapidly charging and discharging in general can significantly diminish the life of batteries.)

Current ultracaps store only a fraction of the electricity that a battery does — and that’s where the problem lies. Ultracapacitors are next-generation capacitors that store more energy and outcompete batteries in a number of applications.

When combined with a battery, an ultracapacitor can better manage sudden energy demands that would normally be placed on the battery, lengthening the battery's operation. Ultracaps are already used to support batteries in a wide range of electronics, and companies are beginning to incorporate ultracaps in wind turbines.

Graphenix has focused on using graphene-based materials to improve ultracaps for a number of reasons. First, they can be recharged continuously, usually over the lifetime of an electronic device, unlike batteries that often must be replaced multiple times in the same device. Ultracaps are also more environmentally friendly.

“We think that advanced ultracapacitors could truly change the energy storage market and industry,” Anstey said.