A type of a battery composed of Lithium, the lightest metal and the metal that has the highest electrochemical potential. Lithium, however, is an unstable metal, so Lithium-Ion batteries are made from Lithium ions from chemicals. Because of its lightness and high energy density, Lithium-Ion batteries are ideal for portable devices, such as notebook computers. In addition, Lithium-Ion batteries have no memory effect and do not use poisonous metals, such as lead, mercury or cadmium. The only disadvantage to Lithium-Ion batteries is that they are currently more expensive than NiCad and NiMH battery packs.