Charge Your Cellphone In 20 Seconds (Eventually)

New submitter GoJays writes "An 18-year-old from Saratoga, California has won an international science fair for creating an energy storage device that can be fully juiced in 20 to 30 seconds. The fast-charging device is a so-called supercapacitor, a gizmo that can pack a lot of energy into a tiny space, charges quickly and holds its charge for a long time. What's more, it can last for 10,000 charge-recharge cycles, compared with 1,000 cycles for conventional rechargeable batteries, according to the inventor Eesha Khare." This one in particular has been used so far only to power an LED, rather than a phone or laptop, but I hope in a few years near-instant charging of portable electronics will be the norm as supercapacitors grow more common.

Comments

supercapacitors are cool

[jamesh]

The one thing I like about supercapacitors (and non-super capacitors) is how quickly they can release all their energy. I can't wait to hold one up to my ear when it's embedded inside a device whose manufacture was outsourced to the lowest bidder!

Re:supercapacitors are cool

[pv2b]

To extend the reverse-car analogy, the correct analogy is the use case of wanting to transmit a large movie to a USB stick so you can watch it on your TV. Doesn't matter if you have the best-of-the-best USB stick and USB 3.0 in your computer. The bottleneck is still the internet connection. So what you do is that you set your computer to download that large file while you're out doing whatever it is you're doing all day, and copy it over to your USB stick quickly when you get home. (You could even conceivably automate this process or remote control it from your cell phone.) In this scenario, having USB 3.0 *will* help since it'll cut down on the time on getting the movie from your computer to the USB stick.

Analogously, the way you'd do it for a residential charger, is that you'd have the power grid trickle charging a supercapacitor that you have at your home (ideally under some kind of control from the power company, so that they can manage the load on the electric grid) over the course of a few hours, so that when you need the power, you can just plug it in and almost instantly get your car charged up.

Although while we're on the subject of analogies, a better reverse-car analogy would be that of a flush toilet, slowly building up a reservoir of water to then quickly release it when required.

Re:supercapacitors are cool

[ifiwereasculptor]

I think a better toilet-related analogy for slow intake and fast discharge would be someone at an all-you-can-eat taco buffet.

Too much current

[ebcdic]

My phone battery has a capacity of 2.1Ah. To charge it in 20 seconds would require a current of 380 Amps. What kind of charger could safely supply that?

Re:little light on the science details.

[msauve]

"did she have some new angle to the tech?"

Yes. The article was terrible. She almost tripled the energy density of supercapacitors. From her paper:

Methods/Materials
To improve supercapacitor energy density, I designed, synthesized, and characterized a novel core-shell nanorod electrode with hydrogenated TiO2 (H-TiO2) core and polyaniline shell. H-TiO2 acts as the double layer electrostatic core. Good conductivity of H-TiO2 combined with the high pseudocapacitance of polyaniline results in significantly higher overall capacitance and energy density while retaining good power density and cycle life. This new electrode was fabricated into a flexible solid-state device to light an LED to test it in a practical application.

Results
Structural and electrochemical properties of the new electrode were evaluated. It demonstrated high capacitance of 203.3 mF/cm2 (238.5 F/g) compared to the next best alternative supercapacitor in previous research of 80 F/g, due to the design of the core-shell structure. This resulted in excellent energy density of 20.1 Wh/kg, comparable to batteries, while maintaining a high power density of 20540 W/kg. It also demonstrated a much higher cycle life compared to batteries, with a low 32.5% capacitance loss over 10,000 cycles at a high scan rate of 200 mV/s.

Re:little light on the science details.

[msauve]

Correcting myself: She claims to have increased mass specific capacitance by almost 3. I'm not sure how her volume specific capacitance compares - I'd think that would be more important for cell phone use.

Mass energy density of commercial supercaps is 3-5 Wh/kg, but 85 has been seen in the lab, according to Wikipedia. Her's is 20.1, which may be significant if it can be commercialized.

Re:little light on the science details.

[horza]

The problem is that Ubuntu touch doesn't support the 1x1 screen resolution. We need the inventor to release the specs so a Mir graphics driver can be written. I've tried an alpha version and personally find the scroll bars tricky, but then that's always been a problem with Unity. This is the problem with Canonical trying to get one OS to work every device.

Phillip.

Re:Gizmo?

[thegarbz]

but unless she has achieved actual breakthroughs in the field, this is again not nearly as newsworthy as the headline suggests.

She has. The only problem here is that the news itself is dumbed down to the point of being utterly pointless.

Science reporting at it's finest.

Some more numbers

[Attila the Bun]

Interesting numbers. Just to compare, here's the energy densities of lithium-polymer batteries and super-capacitors, taking the values for best easily-available components I could find.

LiPo: 168 W.h/kg, 370 W.h/l

Super-cap: 5.1 W.h/kg, 6.6 W.h/l (I'm being slightly generous to the capacitor here, by counting the energy to discharge it to zero volts. In practice that last bit of energy will not be usable.)

The volumetric figures are most critical for phones, and in those terms batteries are 56x better than super-capacitors. So an improvement of 3x is interesting, but there's a lot more work to do.