Researchers Developed Stable Iron-Chromium Battery
A new ligand-engineered redox flow battery has achieved high efficiency while suppressing parasitic hydrogen evolution.
Updated on Sept. 30, 2026 in Energy
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Scientists have developed an alkaline iron-chromium redox flow battery that utilizes ligand engineering to enhance performance. The system demonstrates rapid kinetics and remains stable through 500 charge cycles.
Why it matters
This innovation addresses the long-standing challenges of sluggish chromium kinetics and parasitic hydrogen evolution in aqueous flow batteries. By stabilizing the electrochemical reaction, the design provides a potential pathway for more cost-effective energy storage.
The cell operates at 1.15 V with a theoretical capacity of 68.07 Ah L. The design uses 2,2-Bis(hydroxymethyl)-2,2',2"-nitrilotriethanol to stabilize an octahedral hexacoordinate chromium chelate.
The details
The engineering technique involves using specific ligands to reshape the electronic configurations of iron and chromium centers, which effectively tunes their redox potentials. This approach successfully manages the chromium(III/IV) couple, which operates at +0.34 V versus the standard hydrogen electrode.
Timeline
September 30, 2026: The research findings were published.
The Big Picture
This discovery shifts the trajectory of grid-scale storage by proving that ligand-tuned chemistry can overcome the inherent instability of iron-chromium systems. It effectively bridges the gap between theoretical capacity and practical energy efficiency, potentially unlocking a new class of low-cost batteries.
The projected raw-material cost of $17.02 kWh suggests this technology could significantly reduce the price of large-scale renewable energy storage systems. If commercialized, these batteries could offer a cheaper, more stable alternative to lithium-ion solutions for storing solar and wind power.
The takeaway
This breakthrough demonstrates how molecular-level engineering can solve macroscopic engineering hurdles in energy storage. Future efforts will likely focus on scaling these cell designs for industrial application.
Further reading
For more information on the latest innovations in grid-scale storage, explore the Energy section.
Source note: This article includes information reported by Nature.
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