Iron–air batteries have been proposed and developed for use as rechargeable stationary power storage or as batteries for automotive applications. The iron-air system has a high theoretical specific energy close to 1200 Wh kg−1, because the air for the cathode can be extracted from the environment rather than being stored inside the battery. However, the achievable specific energy has been around an order of magnitude lower. This is mainly caused by parasitic reactions such as hydrogen evolution, and the large overpotentials at the air cathode caused by slow electrochemical reaction kinetics. In this article, the history of the iron-air battery is outlined, followed by a description of the construction of the battery, and the current state of research into its uses.

Second Edition.--This is an update of M. Egashira, SECONDARY BATTERIES – METAL-AIR SYSTEMS | Iron–Air (Secondary and Primary), Editor(s): Jürgen Garche, Encyclopedia of Electrochemical Power Sources, Elsevier, 2009, Pages 372–375, ISBN 9780444527455, https://doi.org/10.1016/B978-044452745-5.00102-7.

Peer reviewed