ARE GRAPHENE BATTERIES THE FUTURE?

Is it the most promising new material or just hype?

Okay, kids, time to put your lab coats on for this one, as today we’re going to talk about something called “graphene.” For years graphene has largely been just a theoretical material, thought to have incredible properties as a super-conductive material for batteries and being incredibly strong and light for building materials. Though much speculation about graphene still exists, it is an amazing material, an allotrope of graphite, in a form that is a single atom thick, making it nearly two-dimensional. An allotrope is a physical description of one of the many forms an element can take, based on the structure. Carbon can form many, including graphene, graphite, carbon nanotubes, fullerenes and diamonds.

Figure 1. Structure of various carbon allotropes: (a) carbon chains; (b) polycyclic aromatic hydro-carbon; (c) graphene; (d) carbon nanotube (CNT); (e) C60; (f) C70; (g) graphite; (h) amorphous carbon; and (i) diamond.

With graphene’s properties, it’s similar to what was proposed that carbon fiber would do for manufacturing, and that, so far, has lived up to the hype, making vehicles from e-bikes to Formula 1 cars stronger and lighter.

Graphene was discovered in 2004 by two researchers at the University of Manchester. It was during one of their “Friday night experiments” that Professors Andre Geim and Kostya Novoselov would try out experimental science that wasn’t necessarily linked to their day jobs. Do those two know how to party or what?!

THE DISCOVERY

In 2004 Geim and Novoselov were polishing some graphite with Scotch tape when they noticed that some of the flakes that came off were thicker than others. They kept separating the fragments again and again until they created flakes just one atom thick, isolating graphene for the first time. And for that effort in 2010 they were recognized with a Nobel Prize.

Graphene has some of the most incredible properties. It can stretch up to 25 percent of its length without breaking, it is 200 times stronger than steel and 40 times stronger than diamonds. It becomes bulletproof when folded to a thickness of two atoms. It’s a more efficient conductor of electricity than copper and has the best thermal conductivity, and it’s flexible and bendable, as well as being very lightweight. It’s even bacteriostatic, UV-absorbing and deodorizing. Will Irish Spring offer a new graphene-scented version?

All these properties make it very promising for anything that uses a battery. It is currently rumored that Tesla is working on battery cells that use graphene to improve storage, battery life, and eventually cut the cost of manufacturing batteries. Lithium-ion batteries can store up to 180 Wh of energy per kilogram, where graphene can store up to 1000 Wh per kilogram. To put that in perspective, a Bosch 625Wh PowerTube weighs in at about 3.5 kilograms. Not all that weight is the battery, some is the case and wiring, but most of it is. Now imagine a battery that weighs only 1 kilogram and has 1.6 times the range.

THEFT-PROOF LOCKS

German security company Hiplok has a graphene-composite-coated U-lock that they launched on Kickstarter that shows a video of someone with an angle grinder attacking the lock for 10 minutes, destroying multiple cutting wheels in the process and they still couldn’t cut through. That lock hasn’t shipped yet and is planned to sell for $300. Considering the price of replacing an e-bike, that could be some pretty good peace of mind. 

FASTER CHARGING

Graphene can also be used as a supercapacitor, which is similar to a battery, but it can charge and discharge at a much higher rate. The idea of faster charging is the interesting part here, because though modern lithium-ion batteries do a good job at handling discharge to power motors (e.g. an e-bike battery and motor system), the hours that the batteries take to recharge can be problematic for some. This technology may come in handy to slash charge times.

“Lithium-ion batteries can store up to 180 Wh of energy per kilogram, where graphene can store up to 1000 Wh per kilogram.” 

Whether used as a supercapacitor or as part of a battery, they both promise longer life spans, easily two to three times as many charge cycles as current li-ion batteries. 

There are some batteries that use graphene sheets as the anode, but this so far hasn’t shown enough of an advantage to make it remarkably better than other materials, and actually silicon surpasses it in capacity.

The problem is that it has to be produced perfectly and is large enough to live up to the hype. There are a handful of companies working on this so far, including Swedish manufacturer 2D Fab, who is collaborating with companies to produce high-quality graphene for a variety of applications, including mixing it with metals, plastics, cement, adhesives and polymers. 

In these uses, it can improve strength while reducing weight and improve thermal and electrical conductivity. But, we certainly are nowhere near a critical mass with production of it. We asked battery scientist Ravi Kempaiah about it, and he says it will take an atomic scale of production for mass use and adoption. In the meantime, it’s useful for certain nanotechnology applications but not for batteries.

At the moment, we don’t have many real-world uses for graphene, but we predict eventually it will ramp up and be used for many of the applications that have been speculated it can do in the next few years.