Journal article
Effect of high oxygen deficiency in nano-confined bismuth sesquioxide
Department of Energy Conversion and Storage, Technical University of Denmark1
National Centre for Nano Fabrication and Characterization, Technical University of Denmark2
Nanocharacterization, National Centre for Nano Fabrication and Characterization, Technical University of Denmark3
Electron matter interaction, Nanocharacterization, National Centre for Nano Fabrication and Characterization, Technical University of Denmark4
Atomic Scale Materials Modelling, Department of Energy Conversion and Storage, Technical University of Denmark5
Functional Oxides, Department of Energy Conversion and Storage, Technical University of Denmark6
Bismuth sesquioxide in its cubic form, i.e. δ-Bi2O3, is the fastest oxygen ionic conductor known with important applications in energy technologies. However, the material is unstable as it undergoes to high-density polymorphic transitions and degradation. In this work, we show that δ-Bi2O3 can be stabilized both at high and low temperatures (T < 775 °C) under low oxygen partial pressure (pO2 < 10-5 atm), where the material is nanostructured in multi-layered thin film coherent heterostructures with yttrium stabilized zirconia (YSZ).
DFT calculation confirms such a form of metastability, also showing that high oxygen defect concentration favors the cubic phase. Moreover, high oxygen deficiency in the nanoionics leads to an unexpected "two-regime" conductivity with high values (σ > 1 S cm-1 at 600 °C) at high pO2 and lower ionic conductivity (σ ~ 0.1 S cm-1 at 600 °C) at low pO2.
Ionic conductivity at low pO2 occurs with high activation energy (Ea > 1.5 eV), suggesting thus a drastic decrease in mobility for high concentration of defects.
Language: | English |
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Year: | 2020 |
Pages: | 024010 |
ISSN: | 25157655 |
Types: | Journal article |
DOI: | 10.1088/2515-7655/ab783a |
ORCIDs: | Fiordaliso, Elisabetta Maria , Kasama, Takeshi , Castelli, Ivano Eligio and Esposito, Vincenzo |