Advances in alkaline batteries

Alkaline rechargeable battery systems have been under development for more than 100 years yet. Different electrochemical couples of positive and negative materials have been subject of research and development, but only the nickel–cadmium system (NiCd) and, since about 10 years, the nickel–metal hydride system (NiMH) have achieved the stage of large volume production. Particularly, sealed NiCd and NiMH cells have been established in a variety of applications. Recent advances with the NiMH system have brought about portable batteries with energy storing capabilities coming close to those of alkaline primary cells. Although representing a technically interesting solution even for electric vehicles, relatively high cost will limit the use of rechargeable alkaline batteries to small high power batteries for hybrid electric vehicles. Basic technological developments for materials suitable for high energy and high power design are described.