Nickel-iron battery
The nickel–iron battery (NiFe battery) are batteries made of iron and nickel oxide hydroxide, with a potassium hydroxide electrolyte. They are very strong, and do not break easily. They can last for more than 20 years. They are slow to charge. They are often used on trains. They are similar to the nickel cadmium battery, but using iron instead of toxic cadmium. The voltage is 1.2 volts per cell, the same as the nickel cadmium battery.
Nickel-iron batteries are very durable. They can be charged many times. They are often associated with Thomas Edison, although he did not invent this type of battery. Edison's company manufactured the batteries until the early 1970s. Today they are made by several Chinese companies. They are often used in applications where a very long service life is required, such as large off-grid solar power systems.
See also
Nickel–zinc battery - a similar battery with a higher capacity and higher voltage, but a shorter lifespan