"Lithium Thin Film" is a technology, not a description (this is confusing). It uses semiconductor manufacturing techniques to build the lithium ion battery onto a silicon substrate, so it is not flexible. Lithium polymer technology builds the battery on a polymer substrate. The distributor Powerstream (powerstream.com) is the best place to look for LiPoly, and I believe they distribute some thin, flexible models of LiPoly.
There was a company called "Infinite Power Solutions" that used to make a battery like this, and which pioneered the technology. Actually, the technology was pioneered at Oak Ridge National Laboratory, but the guy from Oak Ridge founded IPS. IPS raised enough money to build a nice factory in Colorado (I've been there!), but things didn't really work out for them.
For ST to license the tech from Oak Ridge and then to spend 3 years developing it (this project has been going for 3 years, but you couldn't buy it until now), indicates to me that they have some particular customer in mind. Maybe the ESA or something like that.
My opinion of the Lithium-Thin-Film battery is that Li-Poly technology is very nearly as good, at this point, and it is a whole-lot cheaper. For doing energy harvesting, ST is also releasing SPV1050, which competes with the BQ25504 from TI, but it is a lot cheaper. Both of these chips work to charge Li-Poly AND Lithium-Thin-Film batteries from sources like solar, piezo, etc. I have tested all these combinations