Originally Posted by desertstalker
No metallic Li no. The Li present is in a ceramic compound (eg LiMnO4 but there are others) and goes straight to Li Ions in solution.
The danger in Li rechargeable batteries is that high enough temps can cause the electrolyte to decompose (exothermic reaction) producing various hydrocarbons and enough heat to cause the electrode to decompose and produce oxygen. You can probably see what happens next.
However certain designs (LiFePO4 for example) are highly resistant to this behaviour
I donít think that the folks at the local post office have any idea as to the difference between LiPo and LiFePO4. Itís such a complicated rule that I donít really see how it can be enforced. Most have no idea if the phone or computer they are shipping has a lithium battery.