Waterproof lithium metal-air batteries could revolutionize portable power

We've already seen some zinc-air batteries hit the market, and now it sounds like lithium-based cells will be the next type to use air as a cathode. The only problem? Those of you who were awake in 10th grade chemistry might remember that exposing lithium metal to water causes it to explode -- which is why a company called PolyPlus has partnered with the government to develop a unique waterproof lithium metal-air battery that keeps the boom-boom in but lets the buzzy-buzz out. The coating allows lithium ions to seep out while preventing water from getting in, and because the membrane protects the cell, the battery won't discharge in storage. If that sounds a little pie-in-the-sky, well, it is -- PolyPlus founder Steven Visco called lithium metal "the holy-grail battery material." Us, we're a little more skeptical, but we're loving the sounds of prototypes that deliver the juice of current laptop batteries at one-fifth the weight -- hook us up, boys.

[Provost @ Jun 27th 2009 6:08AM]

taking batterys that explode while in use to a whole new level?

[IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII (BarCODE) @ Jun 28th 2009 3:23AM]

They should have gone with Nickel-Zinc (NiZn) batteries instead of Li-on if water was a big concern. Also NiZn batteries have a higher engergy density than Li-on (KG to KWH) and with a 1.6v output they are compatible with most electronics running on Alkaline batteies.

[Benson @ Jun 28th 2009 8:12PM]

Better yet, they should have gone with metallic Li batteries, since they have better energy density. Then they could even try using air as a cathode, for a further improvement. But then they'd need to find a way to protect it from water, because the moisture in normal air reacts with the Li metal and kills the battery; some kind of waterproof barrier that oxygen can penetrate would be in order.

Oh wait... they did. That's why this is news, and NiZn aren't any more.

[IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII (BarCODE) @ Jun 29th 2009 6:53PM]

NiZn battery chemistry is nothing new, it's been around nearly a century.

[someone @ Jun 27th 2009 6:09AM]

what if the waterproof coating gets scraped off?

[Seven @ Jun 27th 2009 6:10AM]

so when are we getting America's first underwater wireless carrier???

[airmanchairman @ Jun 27th 2009 7:07AM]

... to power Google's off-shore / underwater datacentres?

[Xenhas @ Jun 27th 2009 6:14AM]

"What do you mean it's not under warranty? How can you tell it was water damage?"

[CreepinJesus @ Jun 27th 2009 6:23AM]

I'd hardly say it 'exploded'... Caesium on the other hand.. now that is fun science!

[airmanchairman @ Jun 27th 2009 7:08AM]

Give me Magnesium any day!!

[loocas @ Jun 27th 2009 7:19AM]

I use Magnesium every other day at gym. And, man! Do I feel the explosions!

[Jimbo @ Jun 27th 2009 10:58AM]

We used to throw chunks of sodium into the campus pond. I always wanted to try fishing with it.

[BAWWW @ Jun 27th 2009 6:32AM]

sony invented the exploding battery way back

[Kyle @ Jun 27th 2009 7:11AM]

hopefully something like this does eventually hit the market. Battery life on most of the stuff i own is pretty sub-par.

[loocas @ Jun 27th 2009 7:18AM]

Nemo?!

[Crazy J @ Jun 27th 2009 1:41PM]

Zap those Nemos...

Zap Zap!

[Str1ker @ Jun 27th 2009 8:53AM]

I wouldn't trust it...

[graywolf790 @ Jun 27th 2009 9:43AM]

Fun for explosion nerds everywhere. Just add water.

[dagamer43 @ Jun 27th 2009 9:43AM]

Bombers would buy batteries just to take the lithium metal out of them...

oops, I've said too much!

[boe @ Jun 27th 2009 10:15AM]

I'm having a hard time decidingwhat batteries to buy when I go to wallmart - lithium-silver oxide, carbon nanotube, silver-zinc, virus based batteries and now lithium metal air batteries - so many choices. They are all available in the vaporware section.

[Unknown @ Jun 27th 2009 10:25AM]

gee.. what could go wrong

[ninevolttoys @ Jun 27th 2009 11:47AM]

DIY lithium batteries--how hard could it be?

[sotec_productions @ Jun 27th 2009 12:02PM]

Vaporware, exactly.

I can tell you this: I don't give half a shite how much it weighs or if it's water proof. What matters first, foremost, and ONLY to me is battery life and LENGTH. Give me 2,000 charges and triple the charge length AT LEAST and I'm a happy man. I don't care if that adds 5 more pounds to a laptop battery.

Case in point: I have a Zune and a Teclast (Nationite rebranded) mp3 players. The Zune gets, oh, about 5 hours of video. Not terrible. The Nationite gets about 3-5 hours of audio playback. That's horrible when it's rated for 12. that's a bad battery most likely. My Samsung P2 should be here Monday or Tuesday and it has a proven 27 hours, HOURS, of continuous audio playback. Sammy rates it at 30, but of course that's with low bitrate music and all backlighting and screen wakefullness turned to 0. Still. 27 hours, and 6 hours of video.

Battery life. It's ALL about the size when it comes to portable electronics.

[CraigJ @ Jun 27th 2009 1:21PM]

So, MacGyver won't be able to use this to blow a hole in the wall?

[Austin @ Jun 27th 2009 3:05PM]

Eh..........lithium doesn't explode in water.....sorry. It will break down the water into Hydrogen and an lithium-oxide alkaline compound, but it will not explode......

In fact, the reaction is far less eventful than baking soda and vinegar.

When you mix lithium and water, you get hydrogen, lithium hydroxide, and heat. To get an explosion, you need a large amount of lithium, and a large amount of heat. It is possible to get ignition due to the heat of the lithium, but is unlikely. This alkali metal is on the low end of reactivity and isn't really that dangerous.

We had some of this stuff in chem class when we were doing an alkali metals lab. When mixed with water: Potassium reacts extremely violently (bounces and lights on fire) , sodium a little less (most of these didn't light on fire), lithium only released bubbles (NO flame), and the magnesium had to have REALLY hot water to react.

If lithium was really that dangerous, you would never find lithium batteries in anything. Your laptop, your iPod, new Energizer batteries, electronic scales, and more ALL contain lithium - how many of them have exploded recently? Few and far between. -you are not going to find a terrorist using lithium in his next plot.

[Albert Aumentado @ Jun 28th 2009 12:53AM]

It's not the lithium metal that's explosive. it's a combination of the hydrogen gas and heat generated when the lithium metal is exposed to water. It's the difference between throwing a solid chunk of lithium metal into a pond and a lightly crumpled piece (like crumpled paper). The former will fizzle but the latter will explode violently.

When discussing what makes lithium metal dangerous it is not necessarily the lithium metal we should discuss but the form factor. Flame ups can occur not due to lithium metal itself exploding but because of electrical shorts occurring due to dendritic growth on the lithium metal surface. It is form factor that must be discussed as much as materials. Hence...graphite anodes are used. It is hard to use lithium metal and for good reason.

[Scarhawk @ Jun 28th 2009 1:35AM]

Destined to suffer the same problem as zinc-air batteries - they need either a big surface area to let air in, or a fan to move air, which wastes stored energy on moving the fan. Batteries that need air are completely impractical for use in mobile consumer devices.