In-situ structural and performance characterization of double perovskite solid oxide fuel cell electrodes
Suzanne E. Witt, Andrew J. Allen, Megan E. Holtz, Sandra A. Young, Ivan Kuzmenko
In this study, a series of Sr2MMoO6-δ double perovskite solid oxide fuel cell (SOFC) anode materials (where M = Fe, Co, or Ni) were synthesized, and the changes in their morphologies under relevant SOFC operating conditions were explored. Ultra-small angle, small angle and wide angle X-ray scattering (USAXS/SAXS/WAXS) were conducted to determine changes in the microstructures and phase compositions of the anode materials at high temperature and under reducing atmosphere. The stability of the double perovskite structure was found to be highly dependent on the identity of the cation M, such that when M = Fe, the material remained stable over the course of the experiments. However, when M = Co or Ni, much more structural degradation occurred. An in-situ study of the M = Co sample, in which electrical conductivity and USAXS/SAXS/WAXS measurements were conducted simultaneously, revealed the structural degradation mechanisms and electrical performance changes over a range of temperatures. To conduct these measurements, a new cell was developed that allowed for a sample mounted on Pt wire to be placed in the X-ray beam and heated under gas flow comprising 4 % mass H2 and 96 % mass N2. The resulting measurements allowed for the direct comparison of the electrical and morphological changes occurring in the material under operating conditions, such that increases in conductivity could be attributed to the growth of new phases.
, Allen, A.
, Holtz, M.
, Young, S.
and Kuzmenko, I.
In-situ structural and performance characterization of double perovskite solid oxide fuel cell electrodes, ACS Applied Energy Materials, [online], https://doi.org/10.1021/acsaem.0c00376
(Accessed September 28, 2021)