Supercharged Supercapacitors

  • By Ari Daniel
  • Posted 02.02.17
  • NOVA

Supercapacitors run on static electricity and they can recharge and deliver power faster than conventional batteries. Their main drawback is how much energy they can store. But a new technique for making supercapacitors may eliminate that disadvantage and propel them to the forefront of the renewable energy world.

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Running Time: 03:35

Transcript

Ari: There’s a lot of talk about renewable energy. But how feasible is it? A major barrier, believe it or not, is battery storage. And that’s where something called supercapacitors come in. They run on static electricity, and they're capable of recharging and delivering power faster than batteries. But they don't store as much energy… yet. Enter chemist Ric Kaner. You see, supercapacitors are limited by the surface area available for holding electrons.

And Kaner's developed a technique to produce electrodes with lots of surface area out of graphite.

Kaner: This is what graphite looks like as it comes out of the ground. It’s a mineral.

Pogue: And this is what’s in a pencil.

Kaner: Absolutely. So a pencil is nothing more than graphite combined with clay. So this is the material that’s used in essentially all batteries as at least one of the electrodes. So the question is whether you could make this in a high-surface area form. And that is where graphene comes in.

Ari: Graphene is the strongest material ever tested. It’s a layer of carbon that’s one atom thick, giving it extremely high surface area. Kaner says one gram of the stuff would cover four football fields.

Kaner: Graphene provides the high-surface area and conductivity necessary to store large amounts of charge.

Ari: Which means graphene might just allow supercapacitors to be even more... super. And Kaner's lab has come up with a surprising way to make it.

It starts with plain old graphite. This is a chunk of graphite oxide that was mixed with water and then freeze dried.

Maher El-Kady hits it with an ordinary camera flash.

El-Kady: So just watch what is going to happen.

Pogue: Oh!

Ari: The pulse of light’s converted to heat, burning away the oxygen… and leaving behind graphene.

Pogue: That’s graphene right there?

El-Kady: So what’s left over we call it now graphene foam.

Ari: Kaner's lab has developed a system to print exact designs. A layer of plastic gets coated onto the surface of a CD with a solution of graphite oxide. Once dry, it’s inserted into a CD laser labeler.

Pogue: Oh, that’s wild that you put it in upside down.

Ari: But instead of doing its usual job of etching a label, wherever the laser hits the dried graphite oxide, that spot’s transformed into graphene.

Pogue: Whoa ho ho! I like this technology!

Ari: Aside from a graphene likeness of David Pogue, El-Kady's printed two graphene electrodes.

Pogue: Obviously, there’s a huge worldwide market for CDs with pictures of me in graphene but I'm guessing that these are more important to the future of mankind. You've etched circuits out of the graphene?

El-Kady: Yeah. So these circuits are basically micro-supercapacitors. And this stores as much charge as these very bulky capacitors that you will find in any electronic device.

Pogue: You mean this totally flat pattern right now could hold as much charge as this capacitor?

El-Kady: Yes, and we actually made them store a thousand times more charge as this size of capacitor.

Pogue: Wow.

Kaner: If we could scale this to the size of electric vehicles, then you could actually, instead of pulling into a gas station, you'd pull into a charging station and within minutes, your car will be ready to go.

Pogue: An electric car that you can charge as quickly as it would take to fill up?

Kaner: I would definitely like to see that happen and that’s exactly what we're working on.

Pogue: Wow.

Credits

PRODUCTION CREDITS

Producer/Director/Writer
Dan McCabe
Director of Photography
Steve McCarthy
Sound
Glenn Berkovitz & Don Hale
Associate Producer
Julie Crawford
Co-Producer
Cara Feinberg
Digital Editor
Ari Daniel
© WGBH Educational Foundation 2017

MEDIA CREDITS

Music
APM
Additional Visuals
Rendering.no

POSTER IMAGE

(main image: supercapacitor etching)
© WGBH Educational Foundation 2017

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