Iron Salt
Iron Salt

World’s most cost-efficient battery technology

Unrivaled 50€ per kWh: The iron salt technology is destined to shape the future of battery storage beyond lithium, because of the widely available and low-cost iron-based storage medium. For 100% renewable energies around the clock and for a fairer and cleaner world for future generations.

technological benefits

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With the iron salt battery technology, we can offer an unrivaled low-cost energy storage solution of 50€ per kWh and bring the world’s cheapest stationary battery storage to market.


With the Iron Salt battery technology, we are using an iron-based storage medium – and thus one of the most abundant materials in the world.

Temperature resistant

Unlike lithium-based storage systems, Iron Salt batteries can also be operated at very high temperatures and can thus also be used in (sub-) tropical areas.

How does it work?

The heart of an iron salt energy storage system is the redox flow battery unit. It is based on two battery half-cells through which liquid electrolyte is pumped in independent cycles. The half-cells are separated by a membrane and together form the full battery cell. The electrolyte is enriched with iron chloride. During charging or discharging, ions and electrons are transferred between the two half-cells, storing, or releasing energy in the electrolyte. In the uncharged state, both cells have identical oxidation levels; charging leads to reducing the electrolyte in one half-cell and oxidizing electrolyte in the other. Within the negative half-cell, the iron in the electrolyte is deposited as metal on the electrode. The battery capacity is dependent on the iron deposition: an increasing amount of iron deposition leads to a higher capacity. The reaction is fully reversible, and iron is re-dissolved in the electrolyte during discharging.

Suitable Applications

Commercial applications

With the iron salt technology, we provide a technological solution for commercial customers with high energy requirements to cover their energy needs during periods of low wind or low sunshine.

Large-scale batteries

For large-scale, high-power PV plants or wind farms, the iron salt battery technology will be an unrivaled low-cost storage alternative that has the great potential to shape the future of lithium-free electricity storage.

High-temperature environments

High ambient temperatures have so far prevented the establishment of battery storage systems in climatically challenging regions of the world. We are therefore focusing on a particularly temperature-resistant battery technology that can be used worldwide and can thus be used in (sub-) tropical areas as well.

state of development

Successful lab validation

Together with our university cooperation partners we have conducted lab validation tests and successfully confirmed the vast potential of the iron salt battery technology. The results showed a long-term stability without capacity or performance losses at an efficiency of up to 78%.

Scaling up technology

An upscaled iron salt battery demonstrator confirms our long-term test results. This allows our R&D team and our university cooperation partners to speed up material and component selection and system development towards commercial and large-scale solutions.

Iron salt battery cell development

The battery cell development for iron salt based battery systems is already ongoing. We have leveraged our broad knowledge and proven experience from the development of our vanadium-based flow battery cells, which have already been patented in 2019, to make rapid progress in the iron salt development process.

Our cooperation partners

Why battery solutions beyond lithium are needed

10.65 TWh

are needed to power 100% of the USA batteries for 24 hours

If Lithium-Ion Batteries are used:

+ 2,665%

(2.1 Mio t)

of current global annual lithium production capacities is needed.

If Iron-Salt Batteries are used:

+ 2.0%

(2.1 Mio t)

of current global annual iron production is used.

Technological outlook

By bringing the iron salt technology to market, we are striving to offer the most cost-efficient battery storage solution worldwide. Thanks to the low costs and high availability of the iron-based storage medium, we are aiming for a target price of 50€ per kWh – significantly below the current price level for large-scale batteries based on lithium. Iron salt technology has all qualities to be the “Next Generation Battery” of the post-lithium era – and will make an important contribution in providing renewable energies 24/7.