How Do Lithium Ion Batteries Work?

Features

A lithium ion battery is a design that generates electricity through the movement of lithium ions between the cathode and anode. Lithium ion batteries are rechargeable and offer one of the best power-to-weight ratios of any existing battery design.

Chemistry

Most batteries of this design use graphite as the anode. The cathode is typically made from either lithium cobalt oxide, lithium iron phosphate or lithium manganese oxide. The choice of cathode is usually based on the balance between voltage, capacity and charge deterioration. Safety is also an issue, as some mishandled lithium ion battery designs have been known to explode. Electrical current is generated by the migration of the lithium ion from the anode to the cathode, and the reverse when it is being recharged. The electrolyte, or medium between the anode and cathode, is usually a solid lithium salt plus an organic solvent.

Decay

One of the problems with a lithium ion battery is that, unlike other battery designs, it is prone to shelf decay whether it is used or not. While the design is rechargeable, from the time of manufacture a lithium ion battery gradually loses its capacity. The amount of charge it can hold steadily shrinks. If kept fully charged and at room temperature, a lithium ion battery will lose 1/4 of its capacity every year.