Chinese researchers have reported progress in developing an all-iron flow battery that could reduce the cost of large-scale energy storage by replacing lithium with more abundant materials.
The system, developed by a team at the Chinese Academy of Sciences’ Institute of Metal Research, uses iron-based electrolytes in a water-based solution, offering a non-flammable alternative to conventional lithium-ion batteries.
According to the researchers, the approach targets one of the main constraints in renewable energy deployment: the cost of storing intermittent power from solar and wind.
Estimates cited in multiple reports suggest iron is significantly cheaper than lithium as a raw material — in some cases by a factor of around 80 — although this comparison applies to material costs rather than complete battery systems.
Flow battery architectures differ from lithium-ion systems in that energy is stored in liquid electrolytes held in external tanks, allowing capacity to be scaled independently of power output. This makes them more suitable for long-duration, stationary applications such as grid balancing.
All-iron flow battery good for more than 6,000 charge cycles
The Chinese team reports that the battery can achieve more than 6,000 charge cycles without capacity loss, suggesting a potentially long operational life compared with conventional lithium-ion technologies.
Iron-based chemistries also benefit from improved safety characteristics. The use of aqueous electrolytes removes the risk of thermal runaway associated with organic solvents used in lithium-ion batteries.
However, the technology remains at an early stage of development. Flow batteries typically have lower energy density than lithium-ion systems and are unlikely to be suitable for electric vehicle applications.
The work on all-iron flow batteries reflects a broader trend within the battery sector towards alternative chemistries based on abundant materials, including sodium-ion and iron-air systems, as manufacturers seek to reduce reliance on lithium and other critical minerals.
While commercial timelines are unclear, the development highlights continued efforts to reduce the cost of long-duration energy storage — a key requirement for scaling renewable energy systems globally.
