Swapping Graphite Anodes For Silicon Improves Li-ion Battery Capacity Five Times

By Clay Dillow Posted 04.07.2010 at 10:28 am 10 Comments

Self-Assembling Silicon-Carbon Nanocomposite Courtesy of Gleb Yushin, Georgia Tech

Battery capacity is the main thing keeping our lifestyles tethered: to the wall socket, to the gas pump, etc. But while we can extend our batteries' charges with smarter, low-power tech, we're still leaving a good deal of capacity on the table within current lithium-ion technology. A group of researchers at Georgia Tech have devised a “bottom-up” self-assembling nano-composite technique that could tap into that extra capacity, allowing battery makers to swap inefficient graphite anodes for high-performance silicon structures that could increase capacities five-fold.

Li-ion batteries work by transferring lithium ions between a cathode and an anode through a liquid electrolyte. The capacity of a battery is determined by the number of ions it can contain and how quickly those ions can be exchanged. Silicon is an ideal material for anodes because it allows lithium ions to pass in and out of the electrode very quickly. But the expansion and contraction of silicon particles as the ions enter and leave degrades the silicon in short order, ruining the battery. Instead, nearly all li-ion batteries contain graphite anodes that can withstand repeated charge cycles.

But by tapping into self-assembling nanotech, the Georgia Tech team has created a silicon composite material that circumvents the degradation issue, keeping the silicon particles from cracking – potentially opening up lithium-batteries to capacities five times what they currently are. The actual construction of the improved anodes is somewhat complicated, but suffice it to say that if the technology can scale industrially it could be a massive breakthrough for li-ion battery tech. Preliminary tests suggest such an anode could withstand a thousand charge-discharge cycles without degrading.

While it would likely add some cost to our batteries, it could make our portable devices, our hybrids and our EVs run up to five times longer on a charge, or at the very least pack smaller batteries into our devices for the same amount of juice.

[Science Daily]

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10 Comments

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GaTech

04/07/10 at 11:07 am

Gleb Yushin was my Materials professor last semester! His favorite class topic was relating stories from the motherland (Russia). He was a good professor and I'm glad to hear that his research is working out.

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Political_Hippie

04/07/10 at 12:01 pm

Major potential in this research, lighter electric cars make for better efficiency. Phones will have more room for hardware rather than the large battery.

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blackspike2710

04/07/10 at 1:01 pm

Combine this with new iron-nitrogen magnet motors and long range. high speed electric cars will not be far off.

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ajohnson1986

04/07/10 at 2:28 pm

Finally, I'm glad to see that battery tech is gaining. I was afraid that hydrogen would eclipse it and lead us down a dead end but with better battery tech electric cars can be viable again. Now the only issue is generating electricity with cleaner sources so that we're not simply changing where the CO2 is being pumped out (smokestacks instead of exhaust pipes). This is one of many curcial steps to go down that path.

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SLNuke87

04/07/10 at 3:50 pm

I think that battery capacity is one of the biggest technological hurdles the world faces, today. It holds back countless technologies. 200 new nuclear reactors and better batteries, and all of a sudden America has boatloads more of our own money to play with. We can also be much more self sufficient. Batteries are the key.

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kiwiiano

04/07/10 at 5:54 pm

Blackspike... to really make a difference with the planet's problems we have to break this obsession with high speed cars. Our actual target is about 10% of what we currently consume and release, so smaller, lighter vehicles and fewer, shorter journeys are the focus.
If we don't pull this one off, the planet will do it for us by reducing our numbers to about 10%. Or less. :-(

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RAT

04/07/10 at 9:13 pm

Keep it coming ... this is the research that counts !
I've got 3 e-Bikes on Li-Po batteries ..... and they are GREAT. I'm actively looking for the commercialization of the next leap forward to extend my distance / shelf life. Never needed to own a car in the last decade but will keep with a mode of transport with a REALISTIC Passengers weight /Vehicle Weight ratio. After all that's what really counts.

42.

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sokra

04/07/10 at 11:24 pm

Yippy!! We got the battery problem licked - 5x more storage capacity. Except of course the fact that 90% of the world supply of Lithium came from Bolivia and its mines are currently been bought by China. And there are concentration of Japanese and Mideastern nationals living there!!

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twobrain

04/08/10 at 3:31 am

I hope the new combination resolved some of the heat issues in current lithium batteries.

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waltercorreaiii

04/08/10 at 9:35 pm

i thought lithium-sulfide was efficient and cheap. it's four times storage and sulfur is cheap.

which is better lithium-nano-silicon or lithium-sulfide?

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