After recycling a few vapes, a lot of different battery types emerged. None of them had a protective metal enclosure like the world famous 18650 (they have a metal housing anyway), mostly cylindrical soft pouches. 

 hipolitorafael9.45 had a pretty bad experience with his batteries - he could only recharge them a few times! So serious testing and benchmarking is needed. The ones I measured were ~3.7V, so I can't blame them for discharging too much. Updates coming soon.