Rechargeable lithium-ion (Li-ion) cells have a negative electrode (anode) made of lithium compounds. Lithium is a highly reactive material and much lighter than the hydrogen-absorbing metal alloy of the NiMH negative electrode. This results in a higher gravimetric energy density of the Li-ion cell. The cells can be stored for 12 months without requiring maintenance. The expected lifetime of a Li-ion cell in an application is over 1000 cycles.
