Toward a Comprehensive Understanding of Cation Effects in Proton Exchange Membrane Fuel Cells

Publication Type

Journal Article

Date Published

2022-07-26

Authors

ChungHyuk Lee, Xiaohua Wang, Jui-Kun Peng, Adlai Katzenberg, Rajesh K. Ahluwalia, Ahmet Kusoglu, , Siddharth Komini Babu, Jacob S. Spendelow, Rangachary Mukundan, Rod L. Borup

DOI

Abstract

Metal alloy catalysts (e.g., Pt–Co) are widely used in fuel cells for improving the oxygen reduction reaction kinetics. Despite the promise, the leaching of the alloying element contaminates the ionomer/membrane, leading to poor durability. However, the underlying mechanisms by which cation contamination affects fuel cell performance remain poorly understood. Here, we provide a comprehensive understanding of cation contamination effects through the controlled doping of electrodes. We couple electrochemical testing results with membrane conductivity/water uptake measurements and impedance modeling to pinpoint where and how the losses in performance occur. We identify that (1) ∼44% of Co2+ exchange of the ionomer can be tolerated in the electrode, (2) loss in performance is predominantly induced by O2 and proton transport losses, and (3) Co2+ preferentially resides in the electrode under wet operating conditions. Our results provide a first-of-its-kind mechanistic explanation for cation effects and inform strategies for mitigating these undesired effects when using alloy catalysts.

Journal

ACS Appl. Mater. Interfaces

Volume

14

Year of Publication

2022

URL

Issue

31

ISSN

1944-8244

Organization

Research Areas

Laboratory

LANL, LBNL, ANL

Type

Analysis, Durability, Integration