Anion Exchange Membrane Water Electrolysis at 10 A ⋅ cm⁻² Over 800 Hours

Abstract Anion exchange membrane water electrolyzer (AEMWE) is a potentially cost‐effective technology for green hydrogen production. Although the normal current densities of AEMWEs are below 3 A ⋅ cm −2 , operating them at higher current densities represents an efficient, but little‐explored approach to decrease the total cost of hydrogen production. We show here that a benchmark AEMWE has an operational lifetime of only seconds at an ultrahigh current density of 10 A ⋅ cm −2 . By using a more conductive and robust AEM, and judicious choices of ionomers, catalyst, and porous transport layer, we have developed AEMWEs that stably operate at 10 A ⋅ cm −2 with extended lifetimes. The optimized AEMWE has an operational lifetime of more than 800 hours, a 5‐order magnetite improvement over the current benchmark. The cell voltage is only 2.3 V at 10 A ⋅ cm −2 , comparable to those of the state‐of‐the‐art devices operating at current densities lower than 3 A ⋅ cm −2 . This work demonstrates the potential of ultrahigh current density AEMWEs.