Nickel-metal hydride battery
A nickel-metal hydride battery, also known as NiMH, is a secondary cell, meaning it is a rechargeable battery. They are used in cameras and other electronic devices. They are made in several sizes; AA is the most common. They are similar to nickel-cadmium batteries but store twice as much energy. They have a voltage of 1.2 V, the same as the nickel-cadmium battery. They do not contain toxic chemicals like the nickel cadmium battery does. They work by the oxidation of hydrides, such as lanthanum hydride, by nickel(III) oxide.
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They have longer shelf life and are more durable than the lithium-ion battery. They are not as powerful for their size, although the best Ni-MH batteries are very close. They used to be more expensive than nickel cadmium batteries, but in the 21st century the cost is similar.