TY - JOUR
T1 - Topological trends in ionic transport through metal-oxide composites
AU - Wen, Yu
AU - Hashimoto, Ayako
AU - Najib, Abdillah Sani Bin Mohd
AU - Hirata, Akihiko
AU - Abe, Hideki
N1 - Funding Information:
This work was funded by the Precursory Research for Embryonic Science and Technology (PREST) (Grant No. JPMJPR17S7) and the Core Research for Evolutional Science and Technology (CREST) (Grant No. JPMJCR15P1), Japan. We thank the TEM station of the National Institute for Materials Science (NIMS) for the support of using TEM and EDS techniques.
Publisher Copyright:
© 2021 Author(s).
PY - 2021/2/1
Y1 - 2021/2/1
N2 - Although ionic conductors have been thoroughly investigated, topological features of these materials' nanotextures have been surprisingly overlooked. Here, we report fabrication of a metal-oxide nanocomposite consisting of intertwined phases of platinum (Pt) metal and oxygen-ion conductive cerium oxide (CeO2), i.e., Pt#CeO2. Sectional TEM observations coupled with topological analysis demonstrated that Pt#CeO2 composites having different nanostructures can be classified with a topological measure that corresponds to the phase connectivity of CeO2, namely, the Betti number β 0, and another that corresponds to holes of the Pt phase, namely, the Betti number β 1. The samples' oxygen ionic conductivity Pt#CeO2 was measured at elevated temperatures in air by alternating current impedance spectroscopy. It was found that the nanostructure changed from a striped appearance to a maze-like appearance as the value of β 1 / β 0 decreased. Both the activation energy E and the pre-exponential factor σ 0 for the oxygen ionic conductivity were found to be independent of β 1 and exhibited linear, negative correlations with β 0. The topological connectivity of the ion-conductive CeO2 phase, which was quantified with the Betti number β 0, was suitable as a descriptor to correlate the image data of nanostructures with their ionic transport properties.
AB - Although ionic conductors have been thoroughly investigated, topological features of these materials' nanotextures have been surprisingly overlooked. Here, we report fabrication of a metal-oxide nanocomposite consisting of intertwined phases of platinum (Pt) metal and oxygen-ion conductive cerium oxide (CeO2), i.e., Pt#CeO2. Sectional TEM observations coupled with topological analysis demonstrated that Pt#CeO2 composites having different nanostructures can be classified with a topological measure that corresponds to the phase connectivity of CeO2, namely, the Betti number β 0, and another that corresponds to holes of the Pt phase, namely, the Betti number β 1. The samples' oxygen ionic conductivity Pt#CeO2 was measured at elevated temperatures in air by alternating current impedance spectroscopy. It was found that the nanostructure changed from a striped appearance to a maze-like appearance as the value of β 1 / β 0 decreased. Both the activation energy E and the pre-exponential factor σ 0 for the oxygen ionic conductivity were found to be independent of β 1 and exhibited linear, negative correlations with β 0. The topological connectivity of the ion-conductive CeO2 phase, which was quantified with the Betti number β 0, was suitable as a descriptor to correlate the image data of nanostructures with their ionic transport properties.
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U2 - 10.1063/5.0033439
DO - 10.1063/5.0033439
M3 - Article
AN - SCOPUS:85100567289
SN - 0003-6951
VL - 118
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 5
M1 - 054102
ER -