DescentBB

A number of us have all sorts of devices that use Lithium Ion batteries for power. Cell phones, laptops and tablet computers use them- but what happens when these batteries age?

If they're short circuited in any way, they burn explosively at high temperature.

Are there hazards from just having old batteries that are unused in a stored area?

Perhaps you should educate yourself on these batteries first.

Lithium-Ion batteries will not explode unless grossly mishandled and it has nothing to do with the age of the batteries.

Things that will cause them to explode are pretty much limited to: bad/defective charging circuits overcharging them, physical damage/deformation causing internal short circuits, and straight up excessive heat (thermal runaway starts at 350 F).