Cambridge Researchers Present Lithium-Air Battery Breakthrough (google.com)

Reuters reports on a tantalizing advance in battery technology described this week by Cambridge researchers, who have made large enough steps toward a practical lithium-oxygen battery to give a laboratory demo of their system. Commercially available lithium-oxygen batteries would be significant because they would have the potential to deliver the desired power thanks to a high energy density - a measure of energy stored for a given weight - that could be 10 times that of lithium-ion batteries and approach that of gasoline. They also could be a fifth the cost and a fifth the weight of lithium-ion batteries. But problems have beset lithium-oxygen batteries that affect their capacity and lifetime, including troublesome efficiency, performance, chemical reaction and potential safety issues and the limitation of needing pure oxygen rather than plain old air. The Cambridge demonstrator battery employs different chemistry than previous work on lithium-air batteries, for example using lithium hydroxide rather than lithium peroxide. It also uses an electrode made of graphene, a form of carbon. The result was a more stable and efficient battery." Some more about this research can be gleaned from Clare Grey's web page at Cambridge.

Comments

increasing mass??

[Zobeid]

OK, correct me if I'm wrong here, but. . . Won't a lithium-air battery (or an aluminum-air battery, which is also discussed from time to time) actually increase in mass as it discharges? It's pulling oxygen from the air and then binding it into oxides which then have to be carried around until the battery is recharged, right?

Re:Could be

[Rei]

Actually this is far better (from what I can see of it) than any of the previous work on li-air, which I've always taken a rather long view on. While it's really unfortunate I can't read the paper to see the exact details to get an idea of the manufacturing process and read more about the nature of the testing and the drawbacks mentioned, getting 93% efficiency and 2000 cycles on lithium-air are really staggering figures.

The only drawbacks the article mentions are "because the battery's ability to charge and discharge is too low." Soooooo... does that mean low power density? If so, to that I say so what? Today's li-ion cells have way more power density than is needed for propulsion, that's why you have things like Teslas beating supercars - their peak power is something like 20 times what they need to cruise at highway speeds. You could drop discharge power density by an order of magnitude and still have a fine car (optionally with a supercapacitor or small high power-density li-ion pack for bursts if desired) . And for recharge power density... when you have the absurd energy densities provided by li-air, it ceases to matter any more. Seriously, when you can drive all day on a single charge, who needs rapid chargers? You just plug in and charge while you sleep, so it makes no difference whether you can do it in 30 minutes or 8 hours. The top end of Level 2 charging should be enough to give a reasonably efficient vehicle a whole day's drive, no need for Level 3+.

I'd gladly take way lower power density in exchange for way higher energy density.

From the paper's abstract, I see that the chemicals involved in the battery are LiO2, graphene oxide, LiI and dimethoxyethane. LiO2 is cheap. Graphene oxides vary quite a bit depending on the preparation method, so it depends on what varient she's using, but most are cheap. Lithium iodide is cheap. Dimethoxyethane is cheap. Seriously, unless she's using an unusual rare/expensive form of graphene oxide, or is doing something weird and potentially costly in the manufacturing process, these should be affordable.

I really wish I could read more about the details, as that's where the devil lives, but... damned restricted access, yadda yadda yadda. :P

Re: blah blah blah

[Rei]

In case you didn't notice, batteries have dramatically increased in energy density over time. No, a cell phone is not entirely a battery, but battery sizes have shrunk in conjunction with phone sizes, even while their capacity (mAh) has been rising (significantly) over time.

People's inability to notice changing technology around them never ceases to amaze me. It's astounding how fast people get used to new technology and forget what old technology used to be like. It's like picking up an old video game that you played as a teenager and being shocked at how bad the graphics were.