I'm not professing to be a chemist, though a Lithium Ion battery pack doesn't use pure lithium, as shown in this clip (btw, for a Brainiac clip, there weren't enough boobs). There still needs to be an electrolyte, anode and a cathode.
http://en.wikipedia.org/wiki/Lithium_ionAs JD said, Li-ion batteries can give you a very bad day. Also, they are subject to aging (like when your mobile phone battery is crap after 3-4 yrs, or when your laptop turns into a 'plug top' limiting use of your computer to within 2m of a powerpoint).
JD: Any word on the battery pack in DocH's scooter on the roof ?