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Title: Resolving Electrode Morphology’s Impact on Platinum Group Metal-Free Cathode Performance Using Nano-CT of 3D Hierarchical Pore and Ionomer Distribution

Journal Article · · ACS Applied Materials and Interfaces
 [1];  [2];  [2];  [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

This paper reports on the characterization of polymer electrolyte fuel cell (PEFC) cathodes featuring a platinum group metal-free (PGM-free) catalyst using nano-scale resolution X-ray computed tomography (nano-CT) and morphological analysis. PGM-free PEFC cathodes have gained significant interest in the past decade since they have the potential to dramatically reduce PEFC costs by eliminating the large platinum (Pt) raw material cost. However, several challenges remain before they are commercially viable. Since these catalysts have lower volumetric activity, the PGM-free cathodes are thicker and are subject to increased gas and proton transport resistances that reduce the performance. To better understand the efficacy of the catalyst and improve electrode performance, a detailed understanding the correlation between electrode fabrication, morphology, and performance is crucial. In this work, the pore/solid structure and the ionomer distribution was resolved in three dimensions (3D) using nano-CT for three PGM-free electrodes of varying Nafion® loading. The associated transport properties were evaluated from pore/particlescale simulations within the nano-CT imaged structure. These characterizations are then used to elucidate the microstructural origins of the dramatic changes in fuel cell performance with varying Nafion® ionomer loading. We show that this is primarily a result of distinct changes in ionomer’s spatial distribution. The significant impact of electrode morphology on performance highlights the importance of PGM-free electrode development in concert with efforts to improve catalyst activity and durability.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Grant/Contract Number:
AC52-06NA25396
OSTI ID:
1375885
Report Number(s):
LA-UR-17-24486; TRN: US1702002
Journal Information:
ACS Applied Materials and Interfaces, Vol. 8, Issue 48; ISSN 1944-8244
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 76 works
Citation information provided by
Web of Science

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Cited By (9)

Agglomerates in Polymer Electrolyte Fuel Cell Electrodes: Part I. Structural Characterization journal January 2018
Multi-Scale Modeling for Predicting the Stiffness and Strength of Hollow-Structured Metal Foams with Structural Hierarchy journal March 2018
Direct atomic-level insight into the active sites of a high-performance PGM-free ORR catalyst journal August 2017
Achievements, challenges and perspectives on cathode catalysts in proton exchange membrane fuel cells for transportation journal July 2019
Effects of Porous Carbon Morphology, Agglomerate Structure and Relative Humidity on Local Oxygen Transport Resistance journal September 2019
Molecular Design of Single‐Atom Catalysts for Oxygen Reduction Reaction journal February 2020
Integrating PGM‐Free Catalysts into Catalyst Layers and Proton Exchange Membrane Fuel Cell Devices journal December 2018
Progress in the Development of Fe‐Based PGM‐Free Electrocatalysts for the Oxygen Reduction Reaction journal December 2018
Bridging Scales to Model Reactive Diffusive Transport in Porous Media journal January 2020