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Silicon supercapacitor could store electricity inside a silicon chip

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October 23, 2013

A newly developed silicon supercapacitor could allow for the seamless integration of energ...

A newly developed silicon supercapacitor could allow for the seamless integration of energy storage and microchips (Photo: Vanderbilt University)

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A team of researchers at the Vanderbilt University in Nashville, Tennessee has designed a supercapacitor made primarily of silicon that has shown much improved power density over its commercially available alternatives. The advance could allow for interesting integration of battery technology in everyday electronics, from solar cells to smartphones.

Supercapacitors store electricity by gathering ions on the surface of two plates soaked in an electrolyte solution. Because the number of ions that can be stored depends on the surface area of the plates, these are usually coated with materials, such as activated carbon, that are highly porous at the nanometric scale.

While supercapacitors can't quite match the energy storage capabilities of lithium-ion batteries, they can absorb and release charge much more rapidly and have a significantly longer lifespan. Today, supercapacitors are used in applications ranging from stabilizing the power supply in portable electronics to supporting the KERS system in Formula 1 cars.

Scientists have tried to improve on the amount of energy that supercapacitors can store by depositing even more porous materials materials such as carbon nanotubes on their plates, but these attempts have only produced marginal improvements that have been hard to replicate consistently.

Assistant professor Cary Pint and his colleagues at Vanderbilt chose to attack the problem from a new and unusual angle by attempting to build a capacitor out of porous silicon.

The porous silicon was insulated by coating it with a thin layer of graphene (Image: Vande...

The porous silicon was insulated by coating it with a thin layer of graphene (Image: Vanderbilt University)

At first this seemed like an unlikely path, since silicon is known to react strongly with the electrolyte, disrupting the working mechanism of supercapacitors. On the other hand, the electronics industry is very familiar with ways to manipulate silicon precisely and make it highly porous.

Pint and his colleagues coated the porous silicon in carbon and heated the ensemble to about 800° C (1500° F). The process formed a layer of graphene only a few nanometers thick that insulated the silicon from the electrolyte while retaining its highly porous structure.

The researchers found that supercapacitor plates manufactured in this fashion were up to 40 times more energy-dense than those made out of the "naked" silicon, and achieved a performance that significantly improved on current commercial supercapacitors.

Applications

Silicon is the second most abundant element on Earth, and the ability to manufacture supercapacitors from it along with the integrated circuits that it powers could have very interesting repercussions all across the electronics industry.

According to the researchers, it should be possible to build cheap silicon supercapacitors out of the excess silicon contained inside many electronic devices. One such example are solar cells: supercapacitors built out of the silicon in the back side of solar cells could store energy during the day and gradually release it into the energy grid during the hours of peak consumption.

The advance is described in an open-access paper in the journal Nature Scientific Reports.

Source: Vanderbilt University

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion.   All articles by Dario Borghino
7 Comments

If my laptop had half its battery life but could be charged within a minute. I'd buy that.

asdf
23rd October, 2013 @ 05:25 pm PDT

if a super capacitor could easily be mfg'd. cheaply; then so long rare earth element batteries such as lithium ion and lithium phosphate...also china could keep most of it's REE's.

electric vehicle advances quickly with this discovery?

so let us know which corporations buy the license for the research from vanderbuilt! we want to invest in that corp. and thus promote the discovery.

notarichman
24th October, 2013 @ 06:22 am PDT

This is big for the EV. Please keep going back to Vanderbilt so you can inform us of their progress. And an estimated timeline for commercialization would be nice. I might hold off on buying an EV until this is available.

Don Duncan
24th October, 2013 @ 09:57 am PDT

A solar sell that is a battery also, wow what a great step forward.

The world—she is a chang'n.

Jay Finke
24th October, 2013 @ 10:02 am PDT

If supercapacitors can be built into solar cells cheaply enough, it would be major benefit to the solar energy industry. The biggest problem with solar, of course, is that the sun does not always shine. Batteries are the logical solution, but greatly increase the cost of the solar power, as well as the size of the installation. This would be a great solution, IF it is cheap enough and stores enough energy (and does not decrease the overall power output/efficiency of the solar cell). Of course, even if it only stored enough energy to handle power as a few clouds passed over, it would help with short term power fluctuations that bedevil the power industry when private solar is linked to the grid. It would make drops in solar power predictable. Power companies would only have to plan for power drops at night or very long periods of overcast weather, which are predictable.

David Charles Leithauser
24th October, 2013 @ 10:08 am PDT

we all need to find out what Dr Nakamats who invented the Floppy Disc and many other brilliant/zany inventions...but not many ppl have 300+ Patents for IBM systems, has a cosmic energy collector wall on his laboratory and that supplies ALL the large offices/living accom/labs with power yet still has enough to send some to Tokyo Power co... it's better than solar as supposed to collect energy 24hrs a day. Sent him mail asking him why no words/product when the world needs this so much, no reply yet.

PaulYak
24th October, 2013 @ 04:29 pm PDT

Very interesting. While I don't understand a lot of the technical details, stuff like this fascinates me and bodes well for the future I believe.

Bobbafet
29th October, 2013 @ 02:13 pm PDT
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