Technologies

How a lithium-ion battery works

In lithium-ion batteries, graphite and lithium oxide are coated onto copper and aluminum foil.

The ability of atoms to give up their electrons is characterized by an electrochemical potential. Lithium-ion batteries use lithium, metal with the highest electrochemical potential. Lithium is a chemically active metal that reacts even with water and air. But only pure lithium is active, but its oxide, on the contrary, is very stable.

How a lithium-ion battery works

A discharged battery is connected to the power source

The positive pole begins to attract electrons, «pulling them out» from lithium oxide. Since the electrons cannot pass through the electrolyte, they move along the external circuit through the power supply and eventually reach graphite.

At the same time, positive lithium ions are attracted to negative pole, pass through the electrolyte and also reach graphite, finding place between its layers (intercalation).

When all the lithium ions reach graphite and are «captured» by its layers, the battery is fully charged. A large number of lithium ions are stored in the spaces of the graphite crystal lattice. At the same time, compact geometric dimensions are preserved due to the layered and porous structure of graphite.

How a lithium-ion battery works

When all the lithium ions reach graphite and are «captured» by its layers, the battery is fully charged. A large number of lithium ions are stored in the spaces of the graphite crystal lattice. At the same time, compact geometric dimensions are preserved due to the layered and porous structure of graphite.

How a lithium-ion battery works

As soon as we connect any load to our charged lithium-ion battery, the reverse process begins.

In this case, the lithium ions want to return to their original state through the electrolyte. Therefore, they will start moving back through the electrolyte, and the electrons will run through the external circuit, i.e. through load.

An electric current will be generated in the circuit of the incandescent light bulb, which will make this very light bulb glow. As soon as all the electrons «escape» from the graphite, the battery is completely discharged. To charge it again, just put the battery «on charge».