Kinetics of the thermally-induced structural rearrangement of γ-MnO2

Simple item page
dc.contributor.authorDose, WMen_AU
dc.contributor.authorSharma, Nen_AU
dc.contributor.authorWebster, NASen_AU
dc.contributor.authorPeterson, VKen_AU
dc.contributor.authorDonne, SWen_AU
dc.date.accessioned2016-07-06T06:33:28Zen_AU
dc.date.available2016-07-06T06:33:28Zen_AU
dc.date.issued2014-09-17en_AU
dc.date.statistics2016-07-06en_AU
dc.description.abstractThis work presents a temperature-dependent and time-resolved X-ray and neutron diffraction study of the thermally induced structural rearrangement of γ-MnO2. Here, we study electrochemically prepared γ-MnO2, the manganese dioxide phase used in the majority of battery applications, which we find to be ∼64% ramsdellite [a = 4.4351(6) Å, 9.486(2) Å, c = 2.8128(7) Å, and V = 118.33(3) Å3] and ∼36% pyrolusite [a = 4.718(3) Å, c = 2.795(2) Å, and V = 62.22(8) Å3]. Taking a deeper look at the kinetics of the structural rearrangement, we find two steps: a fast transition occurring within 4–8 min with a temperature-dependent ramsdellite to pyrolusite transformation (rate constant 0.11–0.74 min–1) and a slow transition over 4 h that densifies (with changes in unit cell and volume) the ramsdellite and pyrolusite phases to give structures that appear to be temperature-independent. This effectively shows that γ/β-MnO2 prepared in the range of 200–400 °C consists of temperature-independent structures of ramsdellite, unit cell a = 4.391(1) Å, b = 9.16(5) Å, c = 2.847(1) Å, and V = 114.5(6) Å3, and pyrolusite, unit cell a = 4.410(2) Å, c = 2.869(2) Å, and V = 55.79(4) Å3, with a temperature-dependent pyrolusite fraction between 0.45 and 0.77 and increasing with temperature. Therefore, we have linked the temperature and time of heat treatment to the structural evolution of γ-MnO2, which will aid the optimization of γ/β-MnO2 as used in Li-primary batteries. © 2014, American Chemical Society.en_AU
dc.identifier.citationDose, W. M., Sharma, N., Webster, N. A. S., Peterson, V. K., & Donne, S. W. (2014). Kinetics of the thermally-induced structural rearrangement of γ-MnO2. The Journal of Physical Chemistry C, 118(42), 24257-24265. doi:10.1021/jp506914jen_AU
dc.identifier.govdoc6802en_AU
dc.identifier.issn1932-7447en_AU
dc.identifier.issue42en_AU
dc.identifier.journaltitleThe Journal of Physical Chemistry Cen_AU
dc.identifier.pagination24257-24265en_AU
dc.identifier.urihttp://dx.doi.org/10.1021/jp506914jen_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/7160en_AU
dc.identifier.volume118en_AU
dc.language.isoenen_AU
dc.publisherACS Publicationsen_AU
dc.subjectNeutron diffractionen_AU
dc.subjectElectric batteriesen_AU
dc.subjectTemperature dependenceen_AU
dc.subjectPyrolysisen_AU
dc.subjectX-ray diffractionen_AU
dc.subjectBuilding materialsen_AU
dc.titleKinetics of the thermally-induced structural rearrangement of γ-MnO2en_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles