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science & technology technology

Lithium-Air Battery interest increasing

PolyPlus aqeuous lithium air battery
PolyPlus aqeuous lithium air battery

Back on July 8th I posted an article talking about the benefits of a new battery technology I had read about on weblog called Technology Review (originally published on June 26th from MIT). It think it may have originally been linked to either Slashdot or The Register. The blog entry was essentially like a press release from a company in California named PolyPlus. They had just announced the project to create single use high energy density Lithium-Air batteries for the military (most likely for radio communications in the field). The key technology was a new way to wrap the lithium cathode in a waterproof seal while still exposing it to the surrounding air encapsulated in the battery. It seems now some other big monied interests have caught onto this new battery chemistry and are going to produce it as well, but maybe not as a single use battery but instead as a rechargeable battery.

IBM is in the news touting the promise of the lithium-air technology as a potential technological nirvana for autmobile drive trains. Estimates are a 10X increase in energy density per kilogram of battery electrolyte material. If this can be achieved, watch out electric vehicles here we come.

Lithium-ion batteries have the potential to deliver about 585 watt-hours of electricity per kilogram, while lithium-sulfur has a theoretical potential of about 2,600 watt-hours, and lithium-air batteries might reach targets well above 5,000 watt-hours.

If they can be perfected, lithium-air batteries would be ideal for transportation applications, given their potential for high energy capacity and low weight. And, unlike zinc-air batteries, it should be possible to make them rechargeable.

via Lithium-Air Batteries Seen as Hope for Electric Cars – NYTimes.com.

Categories
science & technology technology

Waterproof Lithium-Air Batteries

You may remember High School chemistry class when the topic of reactive metals came up. My teacher had a big slab of pure sodium he kept in a jar under kerosene. The reason for that was to prevent any water, even humidity in the air from reacting with that pure metallic sodium. He would slice pieces off of the sodium to make the surfaces completely free of tarnish. Then pull out the pieces with forceps. And in a display of pyrotechnics and sound and fury, he would place the metal in a flask of water. And it would fizz violently racing around on the surface of the water. It was reacting with the water creating Lye (NaOH-Sodium Hydroxide) and Hydrogen Gas(H2). He would then light the gas to show it was really combustible Hydorgen gas.

Well, Lithium is also a very reactive metal too. Which means it has lots of energy stored up in it that can be tapped to do useful things, like being a battery electrode. Lithium Ion batteries exploit this physical trait to give us the highest energy density batteries on the market save for some exotic specialty chemistries, like Zinc Air. Lithium Ion uses all kinds of tricks to keep the water and moisture out of the mix inside the battery. However these tricks take away from the total energy density of the battery. So now the race is on to use pure metallic lithium in a battery without having to use any tricks to protect it from water.

A company based in Berkeley, CA, is developing lightweight, high-energy batteries that can use the surrounding air as a cathode. PolyPlus is partnering with a manufacturing firm to develop single-use lithium metal-air batteries for the government, and it expects these batteries to be on the market within a few years. The company also has rechargeable lithium metal-air batteries in the early stages of development that could eventually power electric vehicles that can go for longer in between charges.

via Technology Review: Waterproof Lithium-Air Batteries.