Title: Electrode Edge Cobalt Cation Migration in an Operating Fuel Cell: An In Situ Micro-X-ray Fluorescence Study

Abstract

PtCo-alloy cathode electrocatalysts release Co cations under operation, and the presence of these cations in the membrane electrode assembly (MEA) can result in large performance losses. It is unlikely that these cations are static, but change positions depending on operating conditions. A thorough accounting of these Co cation positions and concentrations has been impossible to obtain owing to the inability to monitor these processes in operando. Indeed, the environment (water and ion content, potential, and temperature) within a fuel cell varies widely from inlet to outlet, from anode to cathode, and from active to inactive area. Synchrotron micro-X-ray fluorescence (μ-XRF) was leveraged to directly monitor Co2+ transport in an operating H2/air MEA for the first time. A Nafion membrane was exchanged to a known Co cation capacity, and standard Pt/C electrocatalysts were utilized for both electrodes. Co Kα1 XRF maps revealed through-plane transient Co transport responses driven by cell potential and current density. Because of the cell design and imaging geometry, the distributions were strongly impacted by the MEA edge configuration. These findings will drive future imaging cell designs to allow for quantitative mapping of cation through-plane distributions during operation.

Authors:

Cai, Yun  ^[1];

• Search DOE PAGES for author "Cai, Yun"
• Search DOE PAGES for ORCID "0000-0001-5820-2236"

Ziegelbauer, Joseph M. ^[1]; Baker, Andrew M.  ^[2];

• Search DOE PAGES for author "Baker, Andrew M."
• Search DOE PAGES for ORCID "0000-0001-8648-5579"

Gu, Wenbin ^[1]; Kukreja, Ratandeep S. ^[1]; Kongkanand, Anusorn  ^[1];

• Search DOE PAGES for author "Kongkanand, Anusorn"
• Search DOE PAGES for ORCID "0000-0001-9250-3112"

Mathias, Mark F. ^[1]; Mukundan, Rangachary  ^[2];

• Search DOE PAGES for author "Mukundan, Rangachary"
• Search DOE PAGES for ORCID "0000-0002-5679-3930"

Borup, Rod L.  ^[2]

• Search DOE PAGES for author "Borup, Rod L."
• Search DOE PAGES for ORCID "0000-0001-7647-1624"

---

+ Show Author Affiliations

1. General Motors (GM), Pontiac, MI (United States). Global Fuel Cell Business
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Wed Mar 14 00:00:00 EDT 2018

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); General Motors, Pontiac, MI (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Hydrogen Fuel Cell Technologies Office (HFTO); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division

OSTI Identifier:

1426004

Alternate Identifier(s):

OSTI ID: 1441341; OSTI ID: 1504242

Report Number(s):

LA-UR-18-20372
Journal ID: ISSN 0013-4651; /jes/165/6/F3132.atom

Grant/Contract Number:  

AC52-06NA25396; AC02-06CH11357; EE0007271

Resource Type:

Published Article

Journal Name:

Journal of the Electrochemical Society

Additional Journal Information:

Journal Name: Journal of the Electrochemical Society Journal Volume: 165 Journal Issue: 6; Journal ID: ISSN 0013-4651

Publisher:

The Electrochemical Society

Country of Publication:

United States

Language:

English

Subject:

30 DIRECT ENERGY CONVERSION; Energy Sciences; Fuel cell, XRF, Durability, Co, cation migration; 08 HYDROGEN