A reversible rust process where the oxygen from the air rusts the iron during discharge and then during charging the iron oxide is converted back into iron and oxygen is released.
University of Southern California [3] showed that additives could be used to reduced hydrogen evolution and to increase the charging efficiency to 96%.
Pros
- low cost
- Environmentally friendly
- Abundant raw materials all over the world
- High Theoretical Specific Energy, 764 Wh/kg
- Iron electrode is robust to cycling
Cons
- round trip efficiency ~50%
- compared to ~92% for lithium ion batteries
- hydrogen evolution at the iron electrode
- management of hydrogen gas required
- parasitic process uses energy and reduces efficiency
References
- Battery Technology, Form Energy
- ELuStat: Iron-air battery as stationary energy storage, Fraunhofer UMSICHT
- A Robust and Inexpensive Iron-Air Rechargeable Battery for Grid-Scale Energy Storage, University of Southern California, Loker Hydrocarbon Research Institute
See also
Zinc Air Battery, Aluminium Air Battery, Lithium Air, Nickel Iron Battery