nikkelmetalhüdriid

Nickel metal hydride, often abbreviated as NiMH, is a type of rechargeable electrochemical cell. It utilizes a positive electrode made of nickel oxide hydroxide and a negative electrode made of a hydrogen-absorbing alloy. The electrolyte is typically an alkaline solution, such as potassium hydroxide.

NiMH batteries were developed as an improvement over older nickel-cadmium (NiCd) batteries, offering higher energy density and reduced environmental concerns due to the absence of cadmium. They gained widespread popularity in the late 1990s and early 2000s for use in portable electronics like laptops, digital cameras, and cordless phones. They also found significant application in hybrid electric vehicles.

The chemistry of a NiMH battery involves the reversible absorption and release of hydrogen at the negative electrode. During discharge, hydrogen is released from the alloy and reacts with hydroxide ions to form water, while nickel oxide hydroxide is reduced. During charging, the process is reversed, with water being electrolyzed to produce hydrogen and oxygen, and nickel oxide hydroxide being oxidized.

NiMH batteries are known for their good performance over a wide temperature range and a relatively long cycle life. However, they do suffer from a higher self-discharge rate compared to some other battery chemistries, meaning they lose their charge more quickly when stored. Despite the rise of lithium-ion technology, NiMH batteries remain a viable and cost-effective option for many applications.