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

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: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.