It's cool to see more work being done in this area, Cabe. I've covered some of the innovations in these types of materials and energy sources myself and I find them quite useful technology developments. Some of the energy-harvesting materials in particular that don't even use batteries are interesting as well: http://www.designnews.com/author.asp?section_id=1386&doc_id=262437
This technology reminds me of some of the technology imagined in the movie Vanilla Sky -- where everything had a skin of personal interactive advertising. I would imagine there is a wide range of applications for this flexible technology.
Now researchers from Northwestern University and the University of Illinois have revealed work on a lithium-ion battery that can stretch up to three times its original size.
Its a great technology that lithium-ion batteries can be stretched. As mentioned that batteries can be stretched up-to three times, is this stretching operation is reversible? Is there a limit on number of times battery can be stretched?
It looks like the stretchable battery would have a lifetime limited by the wear between the different materials as it is stretched and released. That may not be a problem for some uses, but it must absoletely be considered as the product is developed. I have seen a few membrane keypads that have just worn away and no longer function on some keys, and so it is clear that wherever there is motion there is wear. There are ways to extend the time until that wear causes failures, but the fixes only can help if they are included. So while there is a solution it is not automatic, it would need to be intentionally included.
But now the whole concept and realization of an actual stretchable battery is certainly a great achievement, no doubt about that.
This technology is ALL well and good. But what about Micro-shorting in the Lithium-ion Battery. I don't believe many have seen the result of a micro-shorted Lithium-ion Battery. Would be VERY BAD if all of a sudden your pants EXPLODED. Just something to consider is all.