Scalable Fe‐Rich Corroded Steel Wool Electrodes for Industrial Anion Exchange Membrane Water Electrolysis with a Two‐Order‐of‐Magnitude Cost Reduction

Abstract Alkaline‐based anion exchange membrane water electrolysis (AEMWE) plays a crucial role in sustainable hydrogen production. However, conventional electrode designs rely on expensive nickel‐based materials and complex fabrication processes, limiting their scalability. This study presents a cost‐effective and scalable approach that transforms ultralow‐cost steel wool into freestanding electrodes for industrial‐scale AEMWE. The fibrous structure, anchoring an activated nickel–iron layered double hydroxide catalyst, enables a highly active bifunctional electrode, achieving 1 A cm⁻² at 1.815 V with an ultralow degradation rate of ≈0.041 mV h⁻¹ over 1800 h. Unlike conventional electrodes, the interwoven fibrous matrix eliminates the need for porous transport layers and forms an interlocking interface with the membrane, significantly enhancing performance and durability. Under industrial conditions, a prototype AEMWE single stack (≈16 cm²) delivers over 16 A at 1.8 V and nearly 30 A at 2.0 V, maintaining stable operation over 400 h under dynamic conditions. This iron‐rich system, based on a scalable one‐pot corrosion process, enables the upcycling of mass‐produced steel wool into 2 m scale electrodes at a cost of 4.59 USD m⁻², over 200 times cheaper than conventional nickel‐based electrodes. These findings establish a new paradigm for cost‐efficient and durable electrode design in industrial AEMWE applications.