What are lithium batteries made of?

A lithium battery is formed of four key components. It has the cathode, which determines the capacity and voltage of the battery and is the source of the lithium ions. The anode enables the electric current to flow through an external circuit and when the battery is charged, lithium ions are stored in the anode.

The electrolyte is formed of salts, solvents and additives, and serves as the conduit of lithium ions between the cathode and anode. Finally there is the separator, the physical barrier that keeps the cathode and anode apart.

Pros and cons of lithium batteries

Lithium batteries have a much higher energy density than other batteries. They can have up to 150 watt-hours (WH) of energy per kilogram (kg), compared to nickel-metal hydride batteries at 60-70WH/kg and lead acid ones at 25WH/kg.

They also have a lower discharge rate than others, losing around 5% of their charge in a month compared to a nickel-cadmium (NiMH) batteries which lose 20% in a month.

However, lithium batteries also contain a flammable electrolyte that can cause small scale battery fires. It was this that caused the infamous Samsung Note 7 smartphone combustions, which forced Samsung to scrap production and lose $26bn in market value. It should be noted that this has not happened to large scale lithium batteries.

Lithium-ion batteries are also more expensive to produce, as they can cost nearly 40% more to produce than nickel-cadmium batteries.