Catalyst: Supercapacitors: new battery technology

Woman switches on television

TANYA HA

Our modern lifestyle is run by battery power. But as technology rapidly develops, we need portable power that's cleaner, greener and longer-lasting.

Images of various portable electronic devices

MAN

With the emergence of all these portable electronic devices in the '90s, there's been a huge demand on energy storage devices.

TANYA HA

The traditional battery stores chemical energy that can be converted into electrical energy. But this simple energy store comes with its own limitations. It's good for slow and steady energy release or recharge, but you can only recharge them a limited number of times. They don't deal well with high power demands, and then you have to dispose of them.

Tanya Ha enters the building of the CSIRO

TANYA HA

So how are these problems being tackled? It appears that these scientists have been souping up an old technology called capacitors. Capacitors store energy by separating electrostatic charge, meaning they can release energy quickly.

Tanya Ha walks with a scientist inside the CSIRO building

MAN

Capacitors have been around for much longer than batteries. But it wasn't until the 1990s, with the advent of nanotechnology, that new materials became available, new nano porous materials that had extremely high surface area, and they could then be applied in a new generation of capacitors. And that's why we call them supercapacitors, because they deliver 1,000 or 10,000 times more energy than regular capacitors.

TANYA HA

So, really, the super in supercapacitors is all about the size of the surface area.

MAN

That's right. The conventional capacitor is just made up of two parallel plates. The larger the plate area, the greater the amount of energy stored. A supercapacitor applies a little trick. Instead of a plain area surface, we have an electrocoat of what's called activated carbon, which is just a form of porous charcoal.

TANYA HA

So it's surface area is dramatically…

MAN

Increased. The main difference between a battery and a supercapacitor is that a capacitor stores charge electrostatically, where a battery stores energy in a chemical reaction. This is a medium-sized supercapacitor. I've got a paperclip here. And on one terminal, I've already attached a paperclip. And if I short the paperclip across to the other terminal, you'll see just how much energy the device contains and how quickly it's transferred. It transfers it so quickly that it melts the wire. Now, a battery of a similar size couldn't do that. You would need a battery about the size of a shoebox to deliver that much current, that quickly.

TANYA HA

This intense energy burst that is delivered from supercapacitors opens up a whole spectrum of applications, from supercapacitors powering the flash in a mobile phone, to powering an electric tram that is able to quickly recharge every time it stops, eliminating the need for overhead wires. So supercapacitors are good for bursts of high-power energy, but what about devices that also need a sustained supply of energy? Maybe a combination of the two would work. And that's exactly what they've done.

Tanya Ha interviewing a woman inside the CSIRO building

TANYA HA

Now, I have to admit I'm not a revhead but this looks a lot like an ordinary car battery to me.

ROSALIE LOUEY

Oh, it certainly does look like one on the outside. But it actually contains a supercapacitor, linked in with a lead acid battery. It weighs the same as a lead acid battery but it lasts at least four times as much as a normal battery.

TANYA HA

The UltraBattery can also outperform the nickel metal hydride batteries currently found in many hybrid cars. Solving the high power demands of car batteries, and even trams, will certainly move us towards green energy use. But will it be the longer life and improved performance of our much-loved gadgets that really fast-tracks this technology?