2. NiMH batteries

Part of the nickel battery family, nickel-metal hydride (NiMH) cells first appeared in laboratories in the 1960s. They were first marketed in the 90s, with the major advantage of higher energy density than NiCd batteries.

Based on hydrogen insertion technology, with no dissolution-precipitation process as with NiCd batteries, NiMH technology became extremely widespread in the 2000s, only to be supplanted by lithium technology in portable and on-board applications. Figure 7 shows an industrial NiMH battery.