镍铁电池是众多充电电池中的一种，它的阳极是氢氧化镍，阴极是铁，电解质(电解液)是氢氧化钾。这种电池的电压通常是1.2V。它很耐用，能够经受一定程度的使用事故（包括过度充电、过度放电、短路、过热），而且经受上述损害后仍能保持很长的寿命。它一般作为后备使用，因为它能够被持续充电而且储存大概20年后仍能工作。而它的缺点则是单位质量(体积)储存的电能少、不能很好的储存电能、在低温时性能低下以及与铅酸电池相比时所突显的高制造成本。这使得它已不怎幺被人使用了。

这类电池之所以能够经受频繁充放电，是由于电解液中的反应物溶解度很低。在充电过程中，由于四氧化三铁的低溶解度造成铁离子的形成十分缓慢。这既是好事，也是坏事。好事是因为铁晶体缓慢地形成可以很好地保护电极，而坏事则是它限制了电池的性能，使得这类电池充电慢，放电也慢。

The nickel–iron battery (NiFe battery) is a rechargeable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. The active materials are held in nickel-plated steel tubes or perforated pockets. It is a very robust battery which is tolerant of abuse, (overcharge, overdischarge, and short-circuiting) and can have very long life even if so treated. It is often used in backup situations where it can be continuously charged and can last for more than 20 years. Due to its low specific energy, poor charge retention, and high cost of manufacture, other types of rechargeable batteries have displaced the nickel–iron battery in most applications.