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New Lithium-Air Battery Delivers 10 Times the Energy Density
Al writes "A company called PolyPlus has developed lithium metal-air batteries that have 10 times the energy density of regular lithium-ion batteries. The anode is made up entirely of lithium metal, and the surrounding air acts as the cathode, making the batteries incredibly energy dense. Previous efforts to make lithium metal batteries have been stymied by the sensitivity of lithium to water in the air. The new batteries use a sophisticated membrane to protect the lithium anode and PolyPlus has even created a version that works underwater, by drawing oxygen through the membrane. Lithium metal-air batteries could be light-weight power sources for demand for plug-in hybrid vehicles and consumer electronics; IBM also recently announced that it would develop lithium metal-air batteries for the energy grid and for transportation."
Or if you even looked at the article, you would see a demo of it running underwater.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
No, it isn't.
Lithium-Ion batteries are dangerous because of very low internal resistance. ie. They can dump a large amount of current in a very short time. This is completely independent of energy density, and future designs could well have higher energy density with less danger of thermal runaway.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Diesel fuel has a very high energy density and very little explosive potential. The danger comes not from the contained energy, but how fast that energy can be released.
"Knowledge is the only instrument of production that is not subject to diminishing returns" -Journal of Political Econom
A lot of people are raising concerns about the risk associated with increasing the energy density of the battery.
I would like to point out that it's difficult to directly compare the risks of two fuel sources without knowing how quickly the energy can be released, and under what conditions it can happen.
For instance, I enjoy working with motorcycles, which typically carry 2 major energy sources: A battery, which supplies starting and auxiliary power, and gasoline, which supplies primary power (including the power required to charge the battery.)
The gasoline in the tank has a far greater energy density and far higher energy potential than the battery, but of the two, the battery poses the greatest risk of injury and explosion.
The gasoline can certainly burn, but will only explode under very specific conditions. The conditions required to set it burning are also very easily removed. In fact, I'm far more concerned about the chemical damaged caused by exposing fuel to skin than I am about the risk of fire or explosion.
On the other hand, I work around the battery with wrenches that are typically grounded against the frame while in use. Even with a disconnected battery, I've had cases (while working on a car) where the wrench contacts the positive terminal of the disconnected battery, creating very heavy gauge short circuit between the terminals. The resulting release of energy will cut through metal and cause severe burns. Likewise, if overdrawn, the battery can release hydrogen which can either vent and ignite, or build internal pressure causing the battery to explode.
An interesting example of a substance that is explosive, has a high energy density, and is safe is C4, which can actually be used to cook food if burned, but will not explode without a blasting cap.
So... Are these batteries a risk? Perhaps. We should look into that. But it's best not to cry about the sky falling without first investigating the matter.
It's Bolivia that has all the Lithium. They are already freaking out about corporations raping their country for profit. IIRC Bolivia has started working on putting policy in place to keep from getting screwed over by large mining firms.
"Like many other producers of crude oil, Bolivia finds itself in a frustrating situation regarding its processing and the refining of its raw materials. It finds company in the history of the incumbent automobile fuel source, petroleum. There is a great deal that the Bolivians could learn from the Saudis regarding what they should do with its lithium reserves and how to extract them. To achieve this, Bolivia will want to strive to find the answer to a number of questions with which the Saudis have dealt over the years, and continues to deal with, such as how wealth will be distributed if the commodity is nationalized, how to maintain a balance between maximum production and environmental stability, and what will stabilize the economy once the commodity is exhausted."
http://www.coha.org/2009/02/lucky-bolivia-and-the-future-of-lithium-in-the-world-economy/
I came to the datacenter drunk with a fake ID, don't you want to be just like me?
However, the big catch is that we can't really produce enough Lithium to make all those batteries.
God, that myth just won't die, will it?
But there's probably no practical way to extract it.
Of course there is. There are dozens of ways. Here's one -- $22-$32/kg. Given that 1kWh of automotive li-ion batteries takes 1-2kg of lithium carbonate and costs about $500, that's a pretty minor cost. More expensive than the surface-mined stuff, mind you (which runs $5-8/kg), but eminently affordable.
I tore these out of your symbol, and they turned into paper.
If you put aluminum in a dust form and then aerosol it, it'll be much worse;
Irrelevant. That *block of aluminum* has more energy density than TNT. *So does aerosolized aluminum*, but so does the block. And it has more energy than gasoline per kilogram, too.
Just because something has high energy density does *not* mean it has a realistic way to release that energy rapidly. And the amount of energy contained within the chemicals that make up a battery (releasable by burning) are often way more than the amount of electrical energy stored in the battery, so saying that because the electricity stored went up 10fold means somehow that the chemical energy that would be released in a fire went up 10fold is just wrong.
If I added a resistor to the inside of a battery so as to waste most of the power of the battery, causing the energy density of the cell to decrease tenfold, would it somehow suddenly become ten times less flammable? If I took the resistor away, would it suddenly become ten times more flammable? Don't act like that's far-fetched, because that's very similar to how a lot of battery improvements work -- lowering the internal resistance, making sure that more of the material within can take part in the desired electricity-storage reactions, and so forth.
There are some incredibly flammable low-energy density batteries, and incredibly fire-resistant high energy density batteries out there. Heck, the Zebra battery has almost the energy density of the lower-end li-ions, and it operates at temperatures of hundreds of degrees in *typical usage*. The amount of electricity stored is simply not inherently correlated with the energy density.
I tore these out of your symbol, and they turned into paper.
I was warned that car batteries can explode if you short-circuit them in this way.
All batteries have internal resistance which naturally limits the amount of current, and therefore power, they can put out. They are unlikely to "explode" in the same way a firecracker explodes... at least from the chemistry alone.
What can happen, though, is the high power draw form shorting a battery will cause a LOT of heat generation. The stuff inside the battery expands with this heat, maybe even vaporizes, and if the battery casing is relatively inflexible it could burst. Bursting is not *quite* the same as exploding.
BUT! Lithium is nasty stuff. If a lithium battery bursts, exposing the lithium directly to the air, then you might get some real pyrotechnics going.
=Smidge=