Decades-long grid storage unlocked with new hydrogen-iron flow battery

Dutch company Elestor has developed a novel hydrogen-iron flow battery designed for long-duration grid energy storage, demonstrating stable performance over tens of thousands of charge-discharge cycles and a potential operational lifespan of 20-25 years. Unlike conventional batteries, this flow battery separates power output and energy storage, using a hydrogen gas circuit at the anode and an aqueous iron-based electrolyte at the cathode. The system relies on abundant, low-cost materials, avoiding supply-chain issues common with lithium, cobalt, or vanadium batteries. Testing under continuous, industrially relevant conditions showed the battery maintained over 80% energy efficiency and more than 75% round-trip efficiency without structural degradation, with periodic operational conditioning restoring optimal performance. Elestor’s prototype incorporated a hydrogen-fed anode, proton-conducting membrane, and carbon-based cathode, circulating an acidic iron salt electrolyte at elevated temperatures and constant current densities. The reversible electrochemical reaction between ferric and ferrous iron ions enables energy storage and release, with