Lithium-ion batteries are now commonly used in rechargeable consumer electronic devices. The main reason lithium is used in these devices is because:

Lithium has a lower electronegativity than nickel in common ruckel-cadmium batteries

Lithium batteries are not as toxic as common alkaline batteries

Lithium batteries have a reduced risk of leakage of chemicals

Lithium batteries achieve a greater amount of energy stored per unit mass than other common batteries