Pathway to complete energy sector decarbonization with available iridium resources using ultralow loaded water electrolyzers

November 12, 2020

Zachary Taie (1,2), Xiong Peng (1), Devashish Kulkarni (3), Iryna V Zenyuk (3,4), Adam Z Weber (1), Christopher Hagen (2), Nemanja Danilovic (1)
ACS Applied Materials & Interfaces, 12, November 2020: 52701–52712. DOI: 10.1111/joa.13353


hydrogen, electrolysis, PEMWE, ultralow loading, iridium, overpotential analysis


We present ultralow Ir-loaded (ULL) proton exchange membrane water electrolyzer (PEMWE) cells that can produce enough hydrogen to largely decarbonize the global natural gas, transportation, and electrical storage sectors by 2050, using only half of the annual global Ir production for PEMWE deployment. This represents a significant improvement in PEMWE’s global potential, enabled by careful control of the anode catalyst layer (CL), including its mesostructure and catalyst dispersion. Using commercially relevant membranes (Nafion 117), cell materials, electrocatalysts, and fabrication techniques, we achieve at peak a 250× improvement in Ir mass activity over commercial PEMWEs. An optimal Ir loading of 0.011 mgIr cm−2 operated at an Ir-specific power of ∼100 MW kgIr −1 at a cell potential of ∼1.66 V versus RHE (85% higher heating value efficiency). We further evaluate the performance limitations within the ULL regime and offer new insights and guidance in CL design relevant to the broader energy conversion field.

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Author Affiliation

(1) Energy Technologies Area, Energy Conversion Group, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
(2) School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Bend, Oregon 97702, United States.
(3) Department of Material Science and Engineering, University of California Irvine, Irvine, California 92697, United States.
(4) National Fuel Cell Research Center, Department of Chemical Biomolecular Engineering,, University of California Irvine, Irvine, California 92697, United States.