Structure evolution of Na2O2 from room temperature to 500 °C

Simple item page
dc.contributor.authorWang, CHen_AU
dc.contributor.authorGui, DYen_AU
dc.contributor.authorXia, Qen_AU
dc.contributor.authorAvdeev, Men_AU
dc.contributor.authorLing, CDen_AU
dc.contributor.authorKennedy, BJen_AU
dc.date.accessioned2021-07-13T23:36:43Zen_AU
dc.date.available2021-07-13T23:36:43Zen_AU
dc.date.issued2020-09-21en_AU
dc.date.statistics2021-07-05en_AU
dc.description.abstractNa2O2 is one of the possible discharge products from sodium–air batteries. Here, we report the evolution of the structure of Na2O2 from room temperature to 500 °C using variable-temperature neutron and synchrotron X-ray powder diffraction. A phase transition from α-Na2O2 to β-Na2O2 is observed in the neutron diffraction measurements above 400 °C, and the crystal structure of β-Na2O2 is determined from neutron diffraction data at 500 °C. α-Na2O2 adapts a hexagonal P62m (no. 189) structure, and β-Na2O2 adapts a tetragonal I41/acd (no. 142) structure. The thermal expansion coefficients of α-Na2O2 are a = 2.98(1) × 10–5 K–1, c = 2.89(1) × 10–5 K–1, and V = 8.96(1) × 10–5 K–1 up to 400 °C, and a ∼10% volume expansion occurs during the phase transition from α-Na2O2 to β-Na2O2 due to the realignment/rotation of O22– groups. Both phases are electronic insulators according to DFT calculations with band gaps (both indirect) of 1.75 eV (α-Na2O2) and 2.56 eV (β-Na2O2). An impedance analysis from room temperature to 400 °C revealed a significant enhancement of the conductivity at T ≥ 275 °C. α-Na2O2 shows a higher conductivity (∼10 times at T ≤ 275 °C and ∼3 times at T > 275 °C) in O2 compared to in Ar. We confirmed, by dielectric analysis, that this enhanced conductivity is dominated by ionic conduction. © 2020 American Chemical Societyen_AU
dc.identifier.citationWang, C.-H., Gui, D.-Y., Xia, Q., Avdeev, M., Ling, C. D., & Kennedy, B. J. (2020). Structure evolution of Na2O2 from room temperature to 500 °C. Inorganic Chemistry, 59(19), 14439-14446. doi:10.1021/acs.inorgchem.0c02234en_AU
dc.identifier.issn1520-510Xen_AU
dc.identifier.issue19en_AU
dc.identifier.journaltitleInorganic Chemistryen_AU
dc.identifier.pagination14439-14446en_AU
dc.identifier.urihttps://doi.org/10.1021/acs.inorgchem.0c02234en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/11051en_AU
dc.identifier.volume59en_AU
dc.language.isoenen_AU
dc.publisherAmerican Chemical Societyen_AU
dc.subjectCrystal structureen_AU
dc.subjectElectric batteriesen_AU
dc.subjectPhase transformationsen_AU
dc.subjectElectric conductivityen_AU
dc.subjectNeutron diffractionen_AU
dc.subjectX-ray diffractionen_AU
dc.titleStructure evolution of Na2O2 from room temperature to 500 °Cen_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.63 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles