CIC energiGUNE validates iron-lead redox flow battery for long-duration storage

CIC energiGUNE has validated 10,000 cycles for a new iron-lead redox flow battery designed for long-duration stationary energy storage. Tested at temperatures between 25 and 30 °C, the technology aims to store surplus renewable energy from solar and wind sources and return it to the grid when production decreases.

Unlike conventional dual-circuit flow batteries, this new architecture utilizes a single electrolyte circuit, which simplifies the system design and reduces the number of required components. The battery uses abundant materials—iron and lead—to avoid reliance on critical raw materials and to leverage existing industrial and recycling chains.

Additionally, the system incorporates a fluorine-free membrane intended to reduce internal resistance and limit unwanted species transport between battery sides. The development has progressed from laboratory cells to larger stacks, with future goals focusing on kW-scale modules through system design and experimental validation.