Cylindrical, prismatic and button-type Nickel-Metal Hydride (Ni-MH) battery is a kind of rechargeable battery with nominal voltage of 1.2V. Ni-MH batteries are designed to meet the requirement for increasingly higher levels of energy demanded by today’s electronic products.

Reaction:

The negative electrode reaction occurring in a Ni-MH cell is

H2O + M + e− → OH− + MH

The charge reaction is read left-to-right and the discharge reaction is read right-to-left. On the positive electrode, nickel oxyhydroxide (NiOOH) is formed.

Ni(OH)2 + OH− → NiO(OH) + H2O + e−