Nexeon Readying to License Silicon Anode Technology for Li-ion Batteries
02 December 2009
| Nexeon silicon anode materials. Left: 1st generation, up to 1,000 mAh g-1. Right: 2nd generation, up to 3,600 mAh g-1. Source: Nexeon. Click to enlarge. |
According to a report in EETimes, UK start-up Nexeon Limited, a spin-off from Imperial College London based on work done by Professor Mino Green, Emeritus Professor at the Department of Electrical Engineering (earlier post), is getting ready to license its silicon anode technology for Li-ion batteries, and is in talks with battery makers.
Nexeon has developed and patented a novel way of structuring silicon so that it delivers extended cycle life and significantly increases anode charge capacity—almost ten times the gravimetric capacity per gram (mAh g-1) compared to carbon anodes. Used in combination with a standard cathode, this can increase cell capacity by 30-40%, Nexeon says.
Silicon is conceptually an attractive anode material for lithium-ion batteries because of its high theoretical charge capacity (4,200 mAh g-1—more than 10 times that of graphite anodes and much larger than various nitride and oxide materials) and low discharge potential. However, silicon anodes are problematic because the material’s volume changes by up to 400% upon the insertion and extraction of lithium ions during charge/discharge cycles. This results in pulverization and capacity fading.
Nexeon says that its patented silicon structures overcome the poor cycle life problems by mitigating the volume expansion issue. These structured silicon anode materials deliver extended cycle life without degradation of capacity.
Nexeon is developing a range of materials with different morphologies and capacities. It says its first commercially available material is capable of capacities up to 1,000 mAh g-1. (As an application example, 2.6g of Nexeon’s first generation structured silicon can replace around 10g of graphite anode material in a commercial 2600 mAh 18650 cell.) Nexeon says it is working on a second-generation material with a different morphology optimized for higher capacities of up to 3,600 mAh
The graphite currently used it cells can be replaced with Nexeon materials and used in combination with conventional polymer binders and current collectors as part of the standard battery manufacturing process, the company says, offering a “drop-in” solution to higher capacities.
The company has a fully automated and instrumented pilot plant in full operation, capable of producing more than 1 kg of material a day (enough material for approximately 500 x 18650 cells). Further proprietary equipment has been designed and is now in the final stages of being tested
Resources
Nexeon patents
When will somebody combine all the best known elements to create higher performance (up to 500 Wh/Kg) cells?
Posted by: HarveyD | 02 December 2009 at 07:08 AM
Soon, I am almost sure.
No one knows of course; but as you imply, this is an excellent example of synergism where many closely and distantly related disciplines are providing the physics, science and engineering to make this happen.
It is also conceivable (but unlikely) that batteries will never get there.
Posted by: ToppaTom | 02 December 2009 at 08:10 AM
Yes Toppa, with battery there is never a guarantee that you can get there. Even if this start-up has something it will take years before we see a real product on the market. Si as a long record of failure in battery technology, so better be cautious with this one, though it is quite en exciting innovation.
Posted by: Treehugger | 02 December 2009 at 08:42 AM
Technological progress is most often slow and incremental. But that is how it is done, despite the feeling by many know-littles that "Its a Conspiracy!" by nefarious un-named Evil-doers, to keep these things off the market.
Posted by: Stan Peterson | 02 December 2009 at 09:14 AM
As TreeHugger says, Si has a long history of promise with problems in reality. This one sounds good and hopefully it will work out.
If so, then it would be possible to make Harvey, and all the rest of us, happy and combine some of these technologies. For example, Nissan's new cathode improvements combined with this anode.
If you combine those two advances alone, then the 2015 Nissan leaf could have a 300 mile range with that same 200kg pack. Or they could cut it down to a 150kg battery and keep a 220 mile range while saving costs and weight. Good choices to have to make.
IF Nexeon can more than triple their current advances and IF all of this holds up in the real world, then those ranges get even better and suddenly BEVs look much more attrative.
Of course, that's still some big "if's" to go through before we believe it....but I can at least hope.
Posted by: DaveD | 02 December 2009 at 09:48 AM
Nexeon's "..offering a “drop-in” solution to higher capacities.." and "The company has a fully automated and instrumented pilot plant in full operation, capable of producing more than 1 kg of material a day (enough material for approximately 500 x 18650 cells)." sounds verifiable.
It's been two years since Stanford University researcher Yi Cui announced silicon anode advances.
"Further proprietary equipment has been designed and is now in the final stages of being tested." could mean commercialization soon - if the costs are reasonable.
Posted by: kelly | 02 December 2009 at 10:08 AM
Very encouraging news. @HarveyD: I get the feeling "very soon"
Posted by: GreenPlease | 02 December 2009 at 10:35 AM
I'm glad Nexeon listened to me :>)
http://www.greencarcongress.com/2009/02/silicon-based-a.html#comments
Posted by: kelly | 02 December 2009 at 11:08 AM
It is interesting that technology will go along with slow progress until it becomes the next "big thing" and then money flows into it and interests grows and break through advances are made. Necessity is the mother of invention, as the old saying goes. When you have good enough batteries for laptops, it stands still. When you can have a market many times larger for EVs, there is advancement. This lesson should not be lost in other areas as well.
Posted by: SJC | 02 December 2009 at 01:12 PM