nikkelmetalhydride

Nickel metal hydride, often abbreviated as NiMH, is a type of rechargeable electrochemical cell. It utilizes a hydrogen-absorbing alloy as its negative electrode (anode) and nickel oxyhydroxide as its positive electrode (cathode). This chemistry allows for a higher energy density compared to older nickel-cadmium (NiCd) batteries, meaning they can store more energy for their size and weight.

NiMH batteries have several advantages. They exhibit a lower self-discharge rate than NiCd batteries, retaining their charge for longer periods when not in use. They also do not suffer from the "memory effect" commonly associated with NiCd cells, where repeated partial discharges can lead to a perceived reduction in capacity. Furthermore, NiMH batteries are generally considered more environmentally friendly as they do not contain the toxic cadmium found in NiCd cells.

However, NiMH batteries also have some drawbacks. Their voltage per cell is typically around 1.2 volts, which is slightly lower than the 1.5 volts of alkaline or NiCd cells, potentially requiring devices to be designed to operate within this range. They can also be more sensitive to overcharging and extreme temperatures, which can degrade their performance and lifespan. Despite these limitations, NiMH batteries have become a popular choice for various applications, including portable electronics, hybrid electric vehicles, and power tools, due to their balance of energy density, recyclability, and reduced environmental impact compared to their predecessors.