Title: Enhancement of Ni–(Y₂O₃)_0.08(ZrO₂)_0.92 fuel electrode performance by infiltration of Ce_0.8Gd_0.2O_2–δ nanoparticles

Abstract

This paper addresses the use of Ce_0.8Gd_0.2O_2–δ (GDC) infiltration into the Ni–(Y₂O₃)_0.08(ZrO₂)_0.92 (YSZ) fuel electrode of solid oxide cells (SOCs) for improving their electrochemical performance in fuel cell and electrolysis operation. Although doped ceria infiltration into Ni–YSZ has recently been shown to improve the electrode performance and stability, the mechanisms defining how GDC impacts electrochemical characteristics are not fully delineated. Furthermore, the electrochemical characteristics have not yet been determined over the full range of conditions normally encountered in fuel cell and electrolysis operation. Here we present a study of both symmetric and full cells aimed at understanding the electrochemical mechanisms of GDC-modified Ni–YSZ over a wide range of fuel compositions and temperatures. Single-step GDC infiltration at an appropriate loading substantially reduced the polarization resistance of Ni–YSZ electrodes in electrolyte-supported cells, as measured using electrochemical impedance spectroscopy (EIS) at various temperatures (600–800 °C) in a range of H₂O–H₂ mixtures (3–90 vol% H₂O). Fuel-electrode-supported cells had significant concentration polarization due to the thick Ni–YSZ supports. Here, a distribution of relaxation times approach is used to develop a physically-based electrochemical model; the results show that GDC reduces the reaction resistance associated with three-phase boundaries, but also appears to improve oxygen transport in themore » electrode. Increasing the H₂O fraction in the H₂–H₂O fuel mixture reduced both the three-phase boundary resistance and the gas diffusion resistance for Ni–YSZ; with GDC infiltration, the electrode resistance showed less variation with fuel composition. GDC infiltration improved the performance of fuel-electrode-supported full cells, which yielded a maximum power density of 2.28 W cm^–2 in fuel cell mode and an electrolysis current density at 1.3 V of 2.22 A cm^–2, both at 800°C.« less

Authors:

Park, Beom-Kyeong  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-1305-8725"

Scipioni, Roberto  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-1926-421X"

Cox, Dalton  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6675-5452"

Barnett, Scott A.  ^[1]

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• Search DOE PAGES for ORCID "0000-0001-9813-7360"

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+ Show Author Affiliations

1. Northwestern University, Evanston, IL (United States)

Publication Date:

Sat Feb 01 00:00:00 EST 2020

Research Org.:

Northwestern Univ., Evanston, IL (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Hydrogen Fuel Cell Technologies Office (HFTO); National Science Foundation (NSF); USDOE

OSTI Identifier:

2229641

Alternate Identifier(s):

OSTI ID: 1598393

Grant/Contract Number:  

EE0008079; FE0027584; DMR-1506925; DMR-1912530; 0008079

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Materials Chemistry. A

Additional Journal Information:

Journal Volume: 8; Journal Issue: 7; Journal ID: ISSN 2050-7488

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY