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Silicon Nanowires Before and After Absorbing Lithium  (Source: Stanford News Service)
New lithium-ion battery using silicon nanowires will store ten times the energy of current lithium-ion batteries

Many electronic devices -- from notebooks to cell phones -- rely on batteries for operation. Rechargeable batteries account for much of the weight in today’s electronic devices so the size of the battery has to be tempered with battery life to get an ideal product.

Stanford assistant professor of materials science and engineering Yi Cui, graduate student Candace Chan and five other researchers made a breakthrough for lithium-ion batteries. The researchers used silicon nanowires in the battery anodes to design new lithium-ion batteries that can hold ten times the electrical charge of current batteries of the same size.

Cui told the Stanford News Service, “It's not a small improvement. It's a revolutionary development.” Cui and his team were able to get the greatly increased electrical storage capacity by growing silicon nanowires on a stainless steel substrate, which provides excellent electrical conduction.

Researchers say that the amount of energy a currently lithium-ion battery can store is dependent on the amount of lithium it can store in its anode typically made from carbon. Silicon has a higher storage capacity than carbon. The use of silicon in lithium-ion batteries had been attempted before but the growing and shrinking process caused by adding and removing lithium caused the silicon to break down severely degrading the performance of the battery.

Chan says, “The people kind of gave up on it [silicon] because the capacity wasn't high enough and the cycle life wasn't good enough. And it was just because of the shape they were using. It was just too big, and they couldn't undergo the volume changes.”

The silicon nanowires used in the researcher’s batteries are tiny at about one-thousandth of the thickness of a sheet of paper and are able to inflate to four times their normal size as they take in lithium without breaking during the duty cycle of the battery. The researchers say that the infrastructure behind silicon is mature meaning the new technology could be pushed to market quickly.

Cui has filed a patent application and is considering starting a company to product batteries based on the technology or collaborating with an established battery maker. This development could also mean much smaller and lighter batteries than we have today that store as much electricity, which would be a huge boon for mobile electronics.

Cui sees the new and improved lithium-ion batteries as being particularly interesting to electric vehicle makers such as GM with its Chevy Volt due in 2010.



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Awesome
By FITCamaro on 12/20/2007 10:29:09 AM , Rating: 2
Would be cool if we could get the batteries even smaller or holding more. Battery technology has been relatively stagnant for years. 20-25 hour charge times for laptops would be sweet. Or next-gen handhelds could have more powerful hardware and/or longer battery life.




RE: Awesome
By nosfe on 12/20/2007 10:32:55 AM , Rating: 1
and just think about all those supercharged explodi-batteries


RE: Awesome
By Anosh on 12/20/07, Rating: 0
RE: Awesome
By FITCamaro on 12/20/2007 10:45:48 AM , Rating: 2
Actually CPUs and GPUs have gotten more efficient lately. Todays quad cores don't consume much more power than yesteryears dual cores. Much of this is due to smaller fabrication processes but also from more efficient designs.

Yes in top end laptops what you say will be true but in standard laptops, battery life will be the focus.


RE: Awesome
By TomZ on 12/20/2007 10:52:38 AM , Rating: 1
quote:
Whatever capacity added to the batteries in the case of laptops will be eaten by even more power hungry components. Probaby the GPU or CPU.

Not necessarily in all cases. Better batteries would also enable laptop OEMs to develop long battery life laptops that can go 10-20 hours on a charge. Or it would allow for the use of higher-power components while maintaining the same battery life as today.


RE: Awesome
By Terberculosis on 12/20/2007 10:54:04 AM , Rating: 2
quote:
Whatever capacity added to the batteries in the case of laptops will be eaten by even more power hungry components. Probaby the GPU or CPU.


Only if these new super batteries can also absorb all the excess thermal output.


RE: Awesome
By mcnabney on 12/20/2007 11:38:57 AM , Rating: 2
They didn't say anything about having a different voltage than other Li-Ion batteries. If it is the same the battery will just last longer. Constant heat production would be the same.


RE: Awesome
By Doormat on 12/20/2007 11:43:46 AM , Rating: 2
I would expect that we'd see much lighter devices with 5-8 hours on a charge. I doubt we'd see many devices with more than 12 hours, the manufacturers will just size down the battery to make it smaller and lighter. It'd be great to have a 3G cell phone that lasts a week on a charge, or an iPod touch that would last an entire 8 hour transpacific flight.

But yea, the biggest implication for these batteries seems to be in electric vehicles. Being able to do 100+ miles on a single charge would be outstanding. The issue is how quickly you can get charge in and out of the battery - how long will it take to charge and how fast can you drive on electric power.


RE: Awesome
By FITCamaro on 12/20/2007 2:17:57 PM , Rating: 2
I think it's going to be a long time before a purely electric car will be a full-time replacement for a gas powered one. They're good for running around town or going to work and back. Not for long trips though. Even if it can make it 100 miles, thats not that far. The average car can make it 300-400 miles on a tank of gas. Sure the size of the tank varies but the point is that they can make it that far. And if you're running low, it only takes 5 minutes to stop at a gas station and fill up. You're likely never going to see a battery than can boast that.

Hence why I still think hydrogen fuel cells are the answer. It'll have to be modified a little but our current distribution system can be used for it.


RE: Awesome
By Doormat on 12/20/2007 3:43:26 PM , Rating: 2
H2 wont do anything. I'd be willing to venture out on a limb and say that 95% of people's daily driving is under 100 miles. If a vehicle can go 100mi on a single charge then fine.

What we'll probably end up seeing is some cars having an optional small 600rpm diesel engine w/ gas tank, where the engine's entire purpose is to recharge the battery on longer trips. You can engineer the engine to operate at its peak efficiency at a constant speed because its only generating electricity, instead of having to go up and down like a standard engine + transmission when you drive and stop, drive and stop.

Now you only use gasoline on trips of more than 100mi/day. The fuel consumption of the people who actually use the engine will be great and since so few people will use the engine anyways, the worldwide consumption of fuel declines dramatically.


RE: Awesome
By FITCamaro on 12/20/2007 6:47:20 PM , Rating: 2
The issue isn't daily driving. It's that people don't want to have to own one car for daily driving and one to take vacations with. And you're still not going to be able to go as far or as fast with just a small diesel engine trying to charge the battery.

With the Chevy Volt it will have a system somewhat like that. But its not meant for driving across the country.


RE: Awesome
By alan328 on 12/23/2007 9:20:15 AM , Rating: 2
quote:
The issue isn't daily driving. It's that people don't want to have to own one car for daily driving and one to take vacations with.


Hi everyone, i am from Hong Kong.
Hong Kong is famous for danger level of air polution.
Everyday, on the news is like this: "Tomorrow polution index is HIGH to VERY HIGH. People are recommended to stay indoor."

Believe it or not... it is the daily life of HK people...

HK urgently needed to replace all cars with EVs. And, 100 miles per a charge is more than enough for HK, because it means you can drive around the whole city many many times.

But why HK people are still not using EVs? the answer is cost of the battery. A pack of battery cost $40K to 100K HK$, and you need to replace the battery every 3 - 5 years. That is simplely not cost effective when comparing with the cost of gas you may consume in the same duration (a lot of car owners told me the same answer when i ask them why don't they change to EVs in HK).

What dose this new technology mean to HK car owners? For the same capicity of battery, the size of battery will be decrease to 1/10.... which also means Li-ion material inside the battery decease to 1/10.... the result is the cost of replacing the battery is a lot cheaper.

If replacing the battery every 3 - 5 years is still much cheaper than the gas one would consume during the same period, everyone will change to EV. Wish that day come soon.


RE: Awesome
By FITCamaro on 12/20/2007 6:49:39 PM , Rating: 2
And why wouldn't Hydrogen do anything? It's a clean source of fuel that can be stored just like gas (not quite as easily but still). The only issue is finding a way to produce it in mass qualities cheaply and efficiently. And there's been research done in that area too.


RE: Awesome
By CubicleDilbert on 12/20/2007 2:24:13 PM , Rating: 4
You are forgetting Murphy's general "Law of Inertia"!

such as:
The weight of a bicycle is constant, regardless of technology. The lighter and more advanced the bicycle, the heavier the accompanying metal lock.

or:

The working performance of a computer is constant. The more powerful the system, the more power hungry the software. Which says, writing a letter in MS Office anno 1992 takes the same amount of time as writing it in 2007. The perceived speed of the PC is constant. Pentium 1 and Windows 95 is speed-wise similar to Pentium Core and Vista.

therefore:
The battery time of any device is constant, regardless of the underlying battery.
Proof:
Thinkpad 755 (1994) 3-4h
Thinkpad 570 (1998) 3-4h
Thinkpad T23 (2002) 3-4h
Thinkpad T40 (2004) 3-4h
Thinkpad T60 (2007) 3-4h

same with cell phones!
Any new battery performance will be sucked up with more powerful systems and gadget features.

Proof
Siemens C25 (1998) 1 day talking
Siemens C45 (2002) 1 day talking
or
Nokia N95 (2007) 1 day talking

Summa summarum:
a device with this new battery will perform EXACTLY as before (but will have a lot of more performance doing in the end exactly the same work as a generation before)


Recycycle
By AlvinCool on 12/20/2007 11:08:08 AM , Rating: 2
It would be great if by not using carbon and using silica it allowed for better recycling. Hybrids using these batterys would be awesome. Hand tools are already showing extended time and more power but one of our biggest wasters are lawn mowers. With these batterys it may be possible to convert everyone to electric lawn mowers!! Much less the cars stated in the article. If they can do this I hope the first thing they do is make them in AA and AAA so we stop filling our landfills with throw aways and rechargables




RE: Recycycle
By mcnabney on 12/20/2007 11:43:43 AM , Rating: 2
You are right! I never thought of lawn mowers as being a target for this. Those nasty inefficient 2 stroke engines pollute more in one mowing than my two cars do in a week. Except for the commercial ones that are used all the time, most mowers aren't used for more than 2 hours at a time.

And they can't replace the current crop of batteries we use. Li-Ion voltage is too high. 3.6V per cell I believe, which is more than double the 1.5V standard. NiMH run at 1.2 and I have never known why that isn't more of a problem.


RE: Recycycle
By TomZ on 12/20/2007 12:22:13 PM , Rating: 1
Lawn mower engines are 4-stroke, not 2-stroke, at least in the US.


RE: Recycycle
By fic2 on 12/20/2007 1:39:24 PM , Rating: 2
Yes, they are 4-stroke, but they have little, if any pollution controls on them.


RE: Recycycle
By TomZ on 12/20/2007 9:14:28 PM , Rating: 1
Agreed, but they're not burning tons of oil like 2-strokes.


RE: Recycycle
By AlexandertheBlue on 12/20/2007 9:41:43 PM , Rating: 2
Not necessarily. You are assuming that all lawn mowers are new. Many old lawn mowers, especially lawn boys, are 2 stroke.

However that said, I have always preferred gas mowers over electric as they have had more power and are thus able to cut longer grass more easily. With the new battery density hopefully thay are able to remedy this and give decent operating time and recharge time.


RE: Recycycle
By fic2 on 12/20/2007 12:01:33 PM , Rating: 2
Lawn mowers, leaf blowers, weed wackers, etc. All a huge source of environmental pollution including noise pollution. If these could be converted to electrical it would be a huge win.


RE: Recycycle
By Spuke on 12/20/2007 1:27:36 PM , Rating: 2
I'm surprised this isn't done already. Are any of these offered in electric only?


RE: Recycycle
By Spuke on 12/20/2007 1:34:52 PM , Rating: 2
Just checked and there are already electric lawn mowers. I saw them on Sears.com. They don't seem to be anymore expensive than regular mowers.


RE: Recycycle
By kingpotnoodle on 12/21/2007 8:50:42 AM , Rating: 2
Electric lawnmowers (at least in UK) have been available for decades... sure most of the larger "sit-on" mowers are diesel/petrol powered like a small tractor but a great many garden appliances for the average home user are electric... they are not that much quieter than 2 stroke engines though. If you have a garden that's not far from your house then it is hardly a hassle to buy a 20m extension reel, indeed many new houses have electric sockets with built in safety cut out positioned in their garages or near the garden.


RE: Recycycle
By fic2 on 12/20/2007 1:37:43 PM , Rating: 2
Usually electric mowers are plug-in which some people will deal with, but most won't. Same with weed-wackers and leaf blowers.

A lot of lawn work is not done by commercial lawn maintenance people and would need long battery life to think about switching to electric.

I would think with this, current electric motors, the price of gas and the hassle of getting a gas mower started every spring that people might be willing to switch if someone came out with a good battery powered mower.


RE: Recycycle
By Dfere on 12/21/2007 9:31:46 AM , Rating: 2
Uh Uh. When you factor how often you have to throw the whole lawn mower away, I think not. The electric mowers rely on a plastic shim in case the blade encounters resistant to give or strip. I think this is because the something inside the motor would take the direct shock and break instead. I have tried two for my rentals over the last ten years and had to throw both away for lack of replacement parts. Any heavy use strips this shim as well.

For trimming your little yard once a week, perhaps these fit, but I have real estate to mow.


growing and shrinking process
By SurJector on 12/20/2007 1:56:50 PM , Rating: 3
I think this growing and shrinking process of silicon could be put to good use in some implants.




RE: growing and shrinking process
By bkaz on 12/20/2007 7:52:24 PM , Rating: 3
Guy: "Hey, your breasts were bigger yesterday."
Girl: "I forgot to charge them this morning."


Silicon beats carbon...?
By Dfere on 12/20/2007 10:02:22 AM , Rating: 3
Next someone will be talking about superior silicon life forms.....




RE: Silicon beats carbon...?
By Malhavoc on 12/20/2007 10:13:08 AM , Rating: 2
No they won't, because if they do .. the little black men will get them!


By BruceLeet on 12/21/2007 6:10:47 AM , Rating: 2
Will find a big advantage here, as Processors/GPU's are shrinking nodes, AMD's and Intel's roadmap which include 65/55/45/32nm GPU's and Processors, these will draw LESS Power draw LESS Heat but improve on Speeds/Performance, Im sure these would be out by the time they start business on these new batteries, LED screens also draw less power you can definately see some quality products lasting a loonnng time on a single charge.




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