Tuesday, January 17, 2012

IBM Lithium-Air Battery Project Looks Promising

Published January 17, 2012

By Jeff Cobb

Would you believe that eight years from now lithium-air batteries – with energy density nearly equal to gasoline and able to provide five times today’s average EV range – could relegate combustion engines to history?

You’ll believe it when you see it, you say? Well, high hopes have been hyped before, so we can’t say we blame you, but this story making the rounds is based on research by no less than well-regarded IBM researchers on two continents.

"We now have one which looks very promising," said IBM physicist Winfried Wilcke about an electrolyte material that could lead to a working lithium-air battery prototype by 2013.

Wilcke works at IBM's Almaden laboratories in San Jose, Calif., and he and Alessandro Curioni at IBM's Zurich lab in Switzerland used a Blue Gene supercomputer to find an alternative electrolyte for the present close-but-no-cigar lithium-air battery.

But let’s back up a minute: What is lithium air, you ask?

According to New Scientist.com which broke the brief story, lithium-air batteries differ from lithium-ion batteries by using carbon for their positive electrode instead of metal oxides.

The carbon is lighter and reacts with oxygen in the surrounding air to produce electrical current. While their energy density is through the roof, li-air battery cells have proven chemically unstable, thus shortening lifespan when repeated recharging is attempted, so that rules them out at this point.

To attack the problem Wilcke used a form of mass spectrometry to analyze the lithium-air cells’ underlying electrochemistry. In doing so, he discovered that beyond reacting with the carbon electrode, oxygen was also reacting with the electrolytic solvent (that carries the lithium ions between the electrodes).

So, the aforementioned supercomputer was used to run extremely detailed reaction models to find more viable electrolytes. This scientific detective work included a form of atomistic modelling down to the quantum mechanics of the components, said Curioni.

After all this high-tech sleuthing, the researchers reportedly have a material they think could work. They won't reveal what the electrolyte is but say that several research prototypes have already been demonstrated adding to their positive outlook.

Perhaps the news is also credible because it is coming from IBM, and not a super capacitor maker named EEstor, or some other company with no known track record.

In any event, if they can get a prototype to work, it would solve a major obstacle with lithium-air batteries, said Phil Bartlett, head of electrochemistry at the University of Southampton, UK.

Other practical issues to overcome before lithium air is given the commercial green light would include coping with moist air, Bartlett said. Moisture could make for a hazard the pundits at Fox News wished they could have pinned on the Volt’s LG Chem cells.

"Lithium in water spontaneously catches fire," Bartlett said.

And we all know fire is not a good thing, right?

So, you ask, what do we really have?

At this point, we have positive reported results from reputable research scientists who think they are onto the right trail.

But what do you think? We’ve already anticipated the usual skepticism and jaded responses, but aside from that, what is a realistic attitude to take?


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