Lithium-ion batteries have a number of important
advantages over competing battery technologies.
They're much lighter than other types of rechargeable batteries of
the same size.
They hold their charge. A lithium-ion battery loses only about 5
percent of its charge per month, compared to a 20 percent loss per month for
They have no memory effect, which means that you do not
have to completely discharge them before recharging, as with some other battery chemistries.
Lithium-ion batteries can handle hundreds of charge/discharge cycles.
The electrodes of a lithium-ion battery are made of lightweight
lithium and carbon. Lithium is a highly
reactive element, meaning that a lot of energy can be stored in its atomic
bonds. This translates into a very high energy density for
Here is a way to get a perspective on the energy density difference.
lithium-ion battery can store 150 watt-hours of electricity in 1 kilogram [2.2 pounds] of
So in summary; lithium-ion batteries can be smaller or lighter, have a higher
voltage and hold a charge longer than other types of batteries.
A NiMH (nickel-metal hydride) battery can store
perhaps 100 watt-hours per kilogram [2.2 pounds], although 60 to 70 watt-hours might be more
A lead-acid battery can store only 25 watt-hours per
kilogram [2.2 pounds].
Using lead-acid technology, it takes 6 kilograms [or 13.2 pounds] to store the same
amount of energy that a 1 kilogram [2.2 pounds] lithium-ion battery can. That's a huge
difference [Source: Everything2.com].
Lithium-ion also operate at higher voltages
than other rechargeables, typically about 3.7 volts for lithium-ion vs. 1.2
volts for NiMH or NiCd.
This means a single cell lithium-ion can often be used rather than
multiple NiMH or NiCd cells.