I was interested and excited to hear about this development published by researchers at MIT that could allow lithium iron phosphate batteries to recharge in seconds rather than minutes, and provide extremely useful charge/discharge cycles for vehicle applications.
Lithium-based batteries are in common usage for electronic devices, because they can hold a large charge for their weight (and size). However they are usually expected to provide a steady power rather than high surges of power, and recharging, which has improved considerably, is still typically half an hour or more.
This was not what what suggested by modelling that Professor Gerbrand Ceder undertook at MIT:
About five years ago, however, Ceder and colleagues made a surprising discovery. Computer calculations of a well-known battery material, lithium iron phosphate, predicted that the material's lithium ions should actually be moving extremely quickly.
"If transport of the lithium ions was so fast, something else had to be the problem," Ceder said.
Further calculations showed that lithium ions can indeed move very quickly into the material but only through tunnels accessed from the surface. If a lithium ion at the surface is directly in front of a tunnel entrance, there's no problem: it proceeds efficiently into the tunnel. But if the ion isn't directly in front, it is prevented from reaching the tunnel entrance because it cannot move to access that entrance.
Professor Ceder teamed up with his graduate student, Byoungwoo Kang, to find a way around this effect.
Ceder and Kang theorized that the lithium ions were having trouble finding their way to the crystal structure's express tunnels. The authors helped the ions by coating the surface of the cathode with a thin layer of lithium phosphate glass, which is known to be an excellent lithium conductor. Testing their newly-coated cathode, they found that they could charge and discharge it in as little as 9 seconds.
9 seconds! That's a lot of juice to dump or pick up, a hell of a surge. It's exactly what you need for vehicle acceleration and regenerative braking! And imagine if you will, a city with charging lanes so that electric vehicles could charge in ten seconds and keep going. Now there's a scheme to conjure with.
What else could we use this for? Think immediate future, because lithium iron phosphate, which these guys were using in place of lithium-cobalt, is already a well-established manufacturing material and these fast charge/discharge batteries could start rolling out in two or three years!
UPDATE: This little diary generated an unexpected amount of interest, and my first visit to the Rec list. It is a very cool piece of research, of course, and it's good to see so many people interested in it. Thanks folks!