Performance of Polymer Electrolyte Fuel Cell Electrodes with Atomically Dispersed (AD) Fe-C-N ORR Catalyst

Journal Article · 04 October 2019 · Journal of the Electrochemical Society

DOI: https://doi.org/10.1149/2.0851914jes · OSTI ID:1574201

Ahluwalia, R. K. ^[1]; Wang, X. ^[1]; Osmieri, Luigi ^[2]; Peng, J.-K. ^[1]; Chung, H. T. ^[3]; Neyerlin, Kenneth C ^[2]

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1. Argonne National Lab. (ANL), Argonne, IL (United States)
2. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Activity of (AD)Fe-N-C catalyst with low Fe content is investigated in differential cells prepared by hot pressing anode gas diffusion electrodes (0.2 mg_Pt/cm²) to N211 membrane and brush painting the cathode catalyst ink. Polarization curves obtained in H₂/O₂ show double Tafel slopes which, in conjunction with the redox potential observed in cyclic voltammetry traces, forms the basis for a distributed ORR (oxygen reduction reaction) kinetic model with potential-dependent available sites. Application of this model to polarization data in H₂/air provides the basis for formulating an oxygen transport model and leads to 7.7 ± mA0.6 mA/cm2 catalyst activity at 0.9 V, 31.5-34.3 mA/cm² cell performance at 0.8 V, and 0.8-2 s/cm O₂ transport resistance. A coupled kinetic, O₂ transport and proton transport illustrates the projected improvements needed in catalyst activity and electrode structure to approach the automotive target of 1000 mW/cm² stack power density while meeting the 1.45 kW/degrees C heat rejection constraint at 1.5 cathode stoichiometry. The model indicates that we need twelve-fold higher mass activity for reducing the kinetic losses, doubling of active site density and an engineered electrode structure for 50% lower proton transport resistance, as well as a 50% reduction in electrode thickness to limit the O₂ transport losses.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Program (EE-3F)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1574201
• Report Number(s): NREL/JA-5900-75392
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 14 Vol. 166; ISSN 0013-4651
• Publisher: The Electrochemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English