Silicon Could Give Lithium Ion Batteries 10X More Capacity
Researchers are reporting they have developed a new material made from three-dimensional, highly porous nano-silicon that could give future lithium ion batteries a ten times higher capacity than they currently have.
The storage capacity of current generation lithium ion batteries remains a bottleneck for the widespread adoption of electric cars due to a perceived limited driving range. Although we could argue whether a 100-130 mile range really is that much of a limitation or not, perhaps the better solution is to be able to ignore that argument altogether by increasing battery capacity.
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The main reason current lithium ion batteries have a relatively low storage capacity has to do with the type of anode the batteries use. A lithium ion battery consists of two main parts: a lithium metal oxide cathode and, currently, a graphite anode. During charging the lithium ions migrate from the metal oxide to the anode and get stored between the graphite sheets for later use. When power is needed, the lithium ions discharge back to the cathode.
The graphite anodes currently in use have a low capacity for storing lithium ions, and it is this problem that gives the batteries a low overall storage capacity. Researchers have realized for a while that if the graphite was replaced with a micro-porous silicon structure (somewhat like a nano-sponge made of silicon), the holding capacity of the anode could be increased by ten times.
The problem with this approach is that, up til now, the silicon has easily cracked and pulverized as it was loaded with lithium ions during the charge cycle.
But, as published in the current issue of the journal Angewandte Chemie International (1), a team of scientists from South Korea has discovered a way to bulk produce these nano-silicon sponges so that they can withstand repeated charging and discharging cycles. Not only does this new material have a much higher charge capacity, the nature of its nano-structure allows for rapid charging and discharging.
It’s not clear how long it might be for this material to reach commercialization, but this breakthrough certainly seems promising in the quest to develop higher and higher battery storage capacities.
(1) Angewandte Chemie International Edition, doi: 10.1002/anie.20080435
Image Credit: From the journal article in Angewandte Chemie International
Source: Eurekalert
I’m not a battery expert but the thought that immediately came to mind was to use Silicon Carbide instead of raw silicon or graphite to potentially be a stepping stone.
MIT has also been studying silicon in batteries, they get the same results as the Koreans. Problem is that the silicon breaks down rather quickly - these silicon added batteries don’t last very long.
Nick,
To be completely honest, I would have been more impressed with this technology if they had actually used two dimensional nano silica, instead of three. Since when do we make two dimensional things? And if you eliminate the third dimension then you could stuff an infinite amount of it in three space!
This is exactly the sort of solution needed to extend the capabilities of embeded devices.
As for electric cars are they really cleaner than fossil fuels? Where does the Electricity come from?
they have been talking about it for a while no, I remember two years ago they had a break throw with nanotubs did we see any of it on the market - no… only time will tell what will happen to this technology
This is amazing! What a great find.
With more effort going into running
cleaner cars global warming will
be defeated, and the cost of needed
fuel for the military will be low.
thanks from tony
whats is the life cycle cost?
This sounds like at least a piece of the holy grail for electric cars. With a 10x increase in capacity, you get cheaper plug-in hybrids and practical full BEVs. Yes, where the electricity comes from matters, but there are clean sources today — I have this in Jersey, where it’s possible to buy from alternate power suppliers… mine is 100% renewable power today (being on Atlantic City Electric, we can also buy from the local AC wind farm, but that’s still a bit pricey).
This may address several of the big Li-ion problems: energy density, peak charge/discharge rates (enough power out means it’s practical in a full electric car, enough power in means you can have practical charging stations on-the-road, versus today’s peak of about 4C charging). There may still be the issue of cell aging indepedent of charge/discharge cycles (a problem in Li-ion that’s not inherent in the NiMh used in todays BEVs).
10X capacity increase in the Anode is great. However, don’t we also need a 10X improvement in Cathode capacity before we can report this as an increase in battery energy density?
@ GSP
Actually, no. The bottleneck in any given lithium ion battery is not in the cathode material, but in how many of the ions the anode can hold. The current material used for the anode, graphite, is very durable but doesn’t hold many ions.