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Title: Bulk Migration of Ni/NiO in Ni-YSZ during Reducing Conditions

Understanding the migration of Ni/NiO in Ni-YSZ can potentially help to design a better solid oxide fuel cell (SOFC) anode. We have observed that extensive hydrogen reduction and methane steam reforming of Ni-YSZ caused bulk migration of Ni/NiO to at least ~ 5 ┬Ám deeper from the Ni-YSZ surface. No significant bulk migration effects were detected after simple thermal treatments in non-reducing/non-reforming environment. Surface analysis of a single zirconia grain in the first 10-20 nm region from annealed, hydrogen reduced and methane steam reformed Ni-YSZ shows Ni-enriched surface supporting earlier claims of Ni exsolution. 3D-EBSD analysis of thermally treated sample before exposing it to reducing and reforming environment indicated mixed NiO/YSZ phase with some porosity and random grain orientation. The surface analysis and mapping were carried out using ToF-SIMS and AES whereas EDS maps on FIB sliced areas on Ni-YSZ were utilized for the bulk analysis. The results provide additional information related to complex reactions occurring in SOFC during internal reforming conditions.
Authors:
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Publication Date:
OSTI Identifier:
974936
Report Number(s):
PNNL-SA-64179
Journal ID: ISSN 0013-4651; JESOAN; 26712; KP1704020; TRN: US201007%%895
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the Electrochemical Society, 157(4):B463-B469; Journal Volume: 157; Journal Issue: 4
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 08 HYDROGEN; 30 DIRECT ENERGY CONVERSION; DESIGN; GRAIN ORIENTATION; HYDROGEN; METHANE; POROSITY; SOLID OXIDE FUEL CELLS; STEAM; Grain-sectioning, focused ion beam, Auger electron spectroscopy, methane; Environmental Molecular Sciences Laboratory