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@INPROCEEDINGS{Mowe:1044598,
author = {Mowe, Patrick and Neuhaus, Kerstin},
title = {{E}lectrochemical characterization of pyrochlore materials
for potential application in low-temperature devices},
reportid = {FZJ-2025-03271},
year = {2025},
abstract = {Crystalline solid ion conductors are of huge importance to
contemporary energy and sensor technologies. With the
continuous progression of materials science, these materials
play an increasingly prominent role in the development of
next-generation devices for sustainable energy storage and
generation. Oxide ceramics like yttria-stabilized zirconia
(YSZ) can offer high ionic conductivity at elevated
temperatures in combination with high (electro)chemical
stability, making them pivotal to various electrochemical
devices [1].Electro-chemo-X (EC-X) devices or on-chip
batteries and micro fuel cells, however, are expected to
operate in a much lower temperature range between 200 °C
and room temperature and require chemical stability against
Si and easy thin film preparation, e.g. by sputtering.
Promising fast proton conductors for these applications are
highly doped ceria and zirconia, but there are few reliable
studies on the ionic and electronic conductivity of relevant
materials [2].In recent years, significant attention has
been directed towards materials with the general formula
$A_2^(3+)$ $B_2^(4+)$ $O_7,$ which exhibit remarkable
high-temperature proton conductivity coupled with oxygen ion
conductivity. However, the precise structure of these
materials is often challenging to predict and can vary from
a fluorite-type to a pyrochlore or even a monoclinic
structure, or a mixture of these structures [3]. For this
work, materials with the composition $A_2^(3+)$ $B_2^(4+)$
$O_7$ (with A e.g. La, Y, Sm, Pr and B e.g. Ce, Zr) were
prepared via the Pechini method. Using XRD, SEM and Raman
spectroscopy, the pellets were characterized for purity and
structural information. In order to gain a comprehensive
understanding of the transport properties of the samples,
the ionic and electronic partial conductivities at high
temperatures characterized by impedance spectroscopy and
Hebb-Wagner measurements. Given the low ionic conductivity
at room temperature, atomic force microscopy (AFM)-based
measurement techniques were additionally employed to obtain
information regarding near-surface transport processes in
this temperature regime [4]: Kelvin Probe Force Microscopy
(KPFM) was used to analyze the surface potential, which is a
sensitive indicator of changes in local defect
concentrations and offers information about the bulk and
grain boundary potential differences, thus providing
insights into differences in transport characteristics [5].
The electrochemical results are discussed in line with the
precise structure and in the context of a defect
model.Acknowledgements: The present study was funded by the
German Research Foundation – project
#52316440.Literature:[1] D.A. Agarkov, M.A. Borik, G.M.
Korableva, et al., J Solid State Electrochem 28, (2024)
1901–1908.[2] K. Neuhaus, H. D. Wiemhöfer, Solid State
Ionics. 371 (2021) 115771.[3] M.A. Subramanian, G.
Aravamudan, G.V.s. Rao, Prog. Solid State Chem. 15 (1983)
(2) 55-143.[4] K. Neuhaus, C. Schmidt, L. Fischer, W. A.
Meulenberg, K. Ran, J. Mayer, S. Baumann, Beilstein J.
Nanotechnology. (2021) (12) 1380-1391.[5] S. Sadewasser, G.
T. Kelvin Probe Force Microscopy; 2012.},
month = {Jul},
date = {2025-07-13},
organization = {19th International Symposium on Solid
Oxide Fuel Cells, Stockholm (Sweden),
13 Jul 2025 - 18 Jul 2025},
subtyp = {After Call},
cin = {IMD-4},
cid = {I:(DE-Juel1)IMD-4-20141217},
pnm = {1221 - Fundamentals and Materials (POF4-122)},
pid = {G:(DE-HGF)POF4-1221},
typ = {PUB:(DE-HGF)24},
doi = {10.34734/FZJ-2025-03271},
url = {https://juser.fz-juelich.de/record/1044598},
}