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Title: Atomic Layer Deposited Zirconia Overcoats as On-Board Strontium Getters for Improved Solid Oxide Fuel Cell Nanocomposite Cathode Durability

Abstract

Here, a flow type Atomic Layer Deposition (ALD) reactor was used to deposit 1-10 nm thick porous ZrO2 overcoats within the pores of conventional La0.6Sr0.4Co0.8Fe0.2O3-x (LSCF)-infiltrated Ce0.9Gd0.1O1.95 (GDC) Solid Oxide Fuel Cell (SOFC) cathodes. Here, both coated and uncoated cathodes displayed initial 650 °C polarization resistance (Rp) values of 0.09 ± 0.03 Ω cm2. However, improved stability was observed for cells with zirconia overcoats ≤ 5 nm thick. Specifically, 1000-hour, symmetric cell, open-circuit, 650 °C Rp degradation rates decreased from 45 %/khrs for uncoated LSCF-GDC Nano-Composite Cathodes (NCCs) to 28 %/khrs, 18 %/khrs, and 12 %/khrs for identical LSCF-GDC NCCs with 1, 2, and 5 nm of zirconia overcoat, respectively. In contrast, identical LSCF-GDC NCCs with 10 nm of zirconia overcoat displayed 650 °C Rp degradation rates of 87 %/khrs. Scanning Electron Microscopy and controlled atmosphere impedance tests showed no significant changes in the LSCF infiltrate particle size or microporosity gas concentration polarization resistance with 1000 hours of 650 °C aging. Instead, X-ray Photoelectron Spectroscopy indicated that zirconia overcoats decreased the amount of “surface Sr” on the LSCF, and X-ray Diffraction detected SrZrO3 in samples with 5 or 10 nm thick zirconia overcoats. Hence, the lower degradation rates of LSCF-GDCmore » NCCs with 1-5 nm thick zirconia overcoats were attributed to “clean up” of deleterious “surface Sr” from the LSCF surface via the formation of SrZrO3, while the higher degradation rates of LSCF-GDC NCCs with 10 nm thick zirconia overcoats were attributed to the accumulation of excessive amounts of SrZrO3 hindering oxygen incorporation into the LSCF.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1]
  1. Michigan State University, East Lansing, MI (United States)
  2. University of South Carolina, Columbia, SC (United States)
Publication Date:
Research Org.:
Michigan State Univ., East Lansing, MI (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1673750
Grant/Contract Number:  
FE0031250
Resource Type:
Accepted Manuscript
Journal Name:
ACS Applied Energy Materials
Additional Journal Information:
Journal Volume: 3; Journal Issue: 4; Journal ID: ISSN 2574-0962
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
Solid oxide fuel cell; atomic layer deposition; infiltration; degradation mitigation; cathode; physiology; degradation; oxides; electrodes

Citation Formats

Zhang, Yubo, Wen, Yeting, Huang, Kevin, and Nicholas, Jason D. Atomic Layer Deposited Zirconia Overcoats as On-Board Strontium Getters for Improved Solid Oxide Fuel Cell Nanocomposite Cathode Durability. United States: N. p., 2020. Web. doi:10.1021/acsaem.0c00558.
Zhang, Yubo, Wen, Yeting, Huang, Kevin, & Nicholas, Jason D. Atomic Layer Deposited Zirconia Overcoats as On-Board Strontium Getters for Improved Solid Oxide Fuel Cell Nanocomposite Cathode Durability. United States. doi:10.1021/acsaem.0c00558.
Zhang, Yubo, Wen, Yeting, Huang, Kevin, and Nicholas, Jason D. Mon . "Atomic Layer Deposited Zirconia Overcoats as On-Board Strontium Getters for Improved Solid Oxide Fuel Cell Nanocomposite Cathode Durability". United States. doi:10.1021/acsaem.0c00558.
@article{osti_1673750,
title = {Atomic Layer Deposited Zirconia Overcoats as On-Board Strontium Getters for Improved Solid Oxide Fuel Cell Nanocomposite Cathode Durability},
author = {Zhang, Yubo and Wen, Yeting and Huang, Kevin and Nicholas, Jason D.},
abstractNote = {Here, a flow type Atomic Layer Deposition (ALD) reactor was used to deposit 1-10 nm thick porous ZrO2 overcoats within the pores of conventional La0.6Sr0.4Co0.8Fe0.2O3-x (LSCF)-infiltrated Ce0.9Gd0.1O1.95 (GDC) Solid Oxide Fuel Cell (SOFC) cathodes. Here, both coated and uncoated cathodes displayed initial 650 °C polarization resistance (Rp) values of 0.09 ± 0.03 Ω cm2. However, improved stability was observed for cells with zirconia overcoats ≤ 5 nm thick. Specifically, 1000-hour, symmetric cell, open-circuit, 650 °C Rp degradation rates decreased from 45 %/khrs for uncoated LSCF-GDC Nano-Composite Cathodes (NCCs) to 28 %/khrs, 18 %/khrs, and 12 %/khrs for identical LSCF-GDC NCCs with 1, 2, and 5 nm of zirconia overcoat, respectively. In contrast, identical LSCF-GDC NCCs with 10 nm of zirconia overcoat displayed 650 °C Rp degradation rates of 87 %/khrs. Scanning Electron Microscopy and controlled atmosphere impedance tests showed no significant changes in the LSCF infiltrate particle size or microporosity gas concentration polarization resistance with 1000 hours of 650 °C aging. Instead, X-ray Photoelectron Spectroscopy indicated that zirconia overcoats decreased the amount of “surface Sr” on the LSCF, and X-ray Diffraction detected SrZrO3 in samples with 5 or 10 nm thick zirconia overcoats. Hence, the lower degradation rates of LSCF-GDC NCCs with 1-5 nm thick zirconia overcoats were attributed to “clean up” of deleterious “surface Sr” from the LSCF surface via the formation of SrZrO3, while the higher degradation rates of LSCF-GDC NCCs with 10 nm thick zirconia overcoats were attributed to the accumulation of excessive amounts of SrZrO3 hindering oxygen incorporation into the LSCF.},
doi = {10.1021/acsaem.0c00558},
journal = {ACS Applied Energy Materials},
number = 4,
volume = 3,
place = {United States},
year = {2020},
month = {3}
}

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This content will become publicly available on March 23, 2021
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