Lithium-ion batteries are 40% lighter than a similar Nickel Metal Hydride (Ni-MH) battery. Lithium-ion batteries feature a high energy density technology that will deliver 430% more working capacity during the lifetime of this battery compared to Ni-Cad batteries. Lithium-ion batteries have an extended length of time during which they hold their charge - even after a long period of storage the batteries will deliver their power.