Pathway to Complete Energy Sector Decarbonization with Available Iridium Resources using Ultralow Loaded Water Electrolyzers

Zachary Taie; Xiong Peng; Devashish Kulkarni; Iryna V Zenyuk; Adam Z Weber; Christopher Hagen; Nemanja Danilovic

doi:10.1021/acsami.0c15687

Pathway to Complete Energy Sector Decarbonization with Available Iridium Resources using Ultralow Loaded Water Electrolyzers

ACS Appl Mater Interfaces. 2020 Nov 25;12(47):52701-52712. doi: 10.1021/acsami.0c15687. Epub 2020 Nov 12.

Authors

Zachary Taie^{1

2}, Xiong Peng¹, Devashish Kulkarni³, Iryna V Zenyuk^{4

3}, Adam Z Weber¹, Christopher Hagen², Nemanja Danilovic¹

Affiliations

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.

PMID: 33183003
DOI: 10.1021/acsami.0c15687

Abstract

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 mg_Ir cm^-2 operated at an Ir-specific power of ∼100 MW kg_Ir^-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.

Keywords: PEMWE; electrolysis; hydrogen; iridium; overpotential analysis; ultralow loading.