A nickel–metal hydride battery (NiMH or Ni–MH) is a type of rechargeable battery. The chemical reaction at the positive electrode is similar to that of the nickel–cadmium cell (NiCd), with both using nickel oxide hydroxide (NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy. Work on NiMH batteries began at the -Geneva Research Center following the technology's invention in 1967. It was based on Ti2Ni+TiNi+x alloys and NiOOH electrodes. Development. A fully charged cell supplies an average 1.25 V/cell during discharge, declining to about 1.0–1.1 V/cell (further discharge may cause permanent damage in the case of multi-cell packs, due to polarity reversal of the weakest cell). Under a light load (0.5 amperes), the starting. Consumer electronicsNiMH batteries have replaced NiCd for many roles, notably small rechargeable batteries. NiMH batteries are commonly available in AA (-size) batteries. These have nominal charge capacities (C) of 1.1–2.8 Ah at 1.2 V,. The negative electrode reaction occurring in a NiMH cell is H2O + M + e ⇌ OH + MHOn the positive electrode, nickel oxyhydroxide, NiO(OH), is formed: Ni(OH)2 + OH ⇌ NiO(OH) + H2O + e The reactions proceed. When fast-charging, it is advisable to charge the NiMH cells with a smart to avoid, which can damage cells. Trickle chargingThe simplest of the safe charging methods is with a fixed low. Alkaline batteriesNiMH cells are often used in digital cameras and other high-drain devices, where over the duration of single-charge use they outperform primary (such as alkaline) batteries. NiMH cells are. • • • • •.
