Performance of Polymer Electrolyte Membrane Water Electrolysis Systems: Configuration, Stack Materials, Turndown and Efficiency

A cell model is developed and validated to analyze the performance of polymer electrolyte membrane water electrolysis (PEMWE) stacks systems. It used characterize oxygen evolution reaction (OER) activity on a TiO2-supported IrO2 catalyst an unsupported powder catalyst. Electrochemical, stack, system thermoneutral potentials are defined determined for isothermal non-isothermal stack operation. Conditions under which potential or flammability H2 in O2 anode stream limits turndown operating temperature. Performance analyzed complete PEMWE with electrolyzer containing IrO2/TiO2 (2 mg/cm2 Ir loading) N117-like mitigated crossover, balance-of-plant (BOP) components, cathode BOP temperature swing adsorption purification, electrical transformer rectifier. At rated power condition, as 2 A/cm2 at 1.9 V, 80 °C, 30 bar pressure, stack/system efficiency 65.3%/60.3% beginning life (BOL), decreasing 59.3%/53.9% end (EOL). The peak 76.3%/70.2% BOL, 71.2%/65.6% EOL. Improvements identified 50% increase current 3 1.8 V.