Title: Effect of Ni content on the morphological evolution of Ni-YSZ solid oxide fuel cell electrodes

Abstract

The coarsening of Ni in Ni–yttria-stabilized zirconia (YSZ) anodes is a potential cause of long term solid oxide fuel cells (SOFC) performance degradation. The specifics of the Ni-YSZ structure—including Ni/YSZ ratio, porosity, and particle size distributions—are normally selected to minimize anode polarization resistance, but they also impact long-term stability. A better understanding of how these factors influence long-term stability is important for designing more durable anodes. The effect of structural details, e.g., Ni-YSZ ratio, on Ni coarsening has not been quantified. Furthermore, prior measurements have been done by comparing evolved structures with control samples, such that sample-to-sample variations introduce errors. Here in this paper, we report a four dimensional (three spatial dimensions and time) study of Ni coarsening in Ni-YSZ anode functional layers with different Ni/YSZ ratios, using synchrotron x-ray nano-tomography. The continuous structural evolution was observed and analyzed at sub-100 nm resolution. It is shown quantitatively that increasing the Ni/YSZ ratio increases the Ni coarsening rate. This is due to both increased pore volume and a decrease in the YSZ volume fraction, such that there is more free volume and a less obtrusive YSZ network, both of which allow greater Ni coarsening. The results are shown to be inmore » good agreement with a power-law coarsening model. In conclusion, the finding is critical for informing the design of SOFC electrode microstructures that limit coarsening and performance degradation.« less

Authors:

Chen-Wiegart, Yu-chen Karen ^[1]; Kennouche, David  ^[2];

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Scott Cronin, J. ^[2]; Barnett, Scott A. ^[2]; Wang, Jun ^[1]

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+ Show Author Affiliations

1. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II
2. Northwestern Univ., Evanston, IL (United States). Department of Materials Science and Engineering

Publication Date:

Thu Feb 25 00:00:00 EST 2016

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1340378

Alternate Identifier(s):

OSTI ID: 1239446

Report Number(s):

BNL-112539-2016-JA
Journal ID: ISSN 0003-6951

Grant/Contract Number:  

SC00112704; AC02-98CH10886

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 108; Journal Issue: 8; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE