News

Stanford researchers reinvent laptop batteries

Stanford University researchers have found a way to reinvent the small lithium-ion batteries that power laptops, cell phones, video cameras and other devices to allow them to hold 10 times the charge they now do.

The new batteries use silicon nanowires.

A laptop that now runs on batteries for two hours could operate for 20 hours with the new batteries.

"It's not a small improvement," Yi Cui said. "It's a revolutionary development."

Cui, who lead the research team, is an assistant professor of materials science and engineering.

The greatly expanded storage capacity of lithium-ion batteries could make them attractive for electric car manufacturers.

In the new batteries, silicon is used instead of carbon to store the charged lithium, which provides power. Silicon can store much more lithium but it has a drawback because being charged and discharged expands and then contracts the silicon and can pulverize the silicon, degrading the batteries.

Cui and his research team found a way around that by using silicon nanowires to store the lithium. The wires also expand, but they don't fracture or degrade the way other silicon shapes do.

-- Don Kazak

Comments

Posted by The-Future-Is-Mobile, a resident of Another Palo Alto neighborhood
on Dec 20, 2007 at 11:34 am

> "It's not a small improvement," Yi Cui said.
> "It's a revolutionary development."

Good going, guys!

Now--when will these batteries be on the shelf at Fry's?


Posted by Walter_E_Wallis, a resident of Midtown
on Dec 20, 2007 at 11:51 am

Ten times the charge = ten times the energy release in a short circuit.


Posted by R Wray, a resident of Palo Verde
on Dec 21, 2007 at 10:05 am

How close is this to the energy density of dynamite?


Posted by Scully, a resident of Charleston Gardens
on Dec 21, 2007 at 10:14 am

Looks like Wally and Wray are going to give up their computers, for fear of being blown up - - hooray!!!


Posted by Walter_E_Wallis, a resident of Midtown
on Dec 21, 2007 at 11:49 am

When was the last time you heard of a work station exploding? Are you the Apple Scully? If so, your experience was with bottles of Pepsi exploding, wasn't it? Everyone knows Apples never reach critical mass.


Posted by R Wray, a resident of Palo Verde
on Dec 22, 2007 at 10:19 am

I decided to answer my own question with a little Googling. The energy density of present lithium batteries is 0.36 million j/kg and dynamite is 4.3 million j/kg. (These values are unverified.) If the Stanford researchers increase the battery density by a factor of ten, this gives a battery energy density equal to 84% that of dynamite.
However, I doubt that a catastrophic battery discharge could happen nearly as fast as a dynamite explosion, so the instantaneous power release from the battery would be less than a dynamite explosion.


Posted by Lyle, a resident of another community
on Dec 22, 2007 at 1:40 pm

Here is an extensive detailed interview with the silicon nanowire's inventor:
Web Link


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