Comparison of small polaron migration and phase separation in olivine LiMnPO4 and LiFePO4 using hybrid density functional theory
Author(s)
Ong, Shyue Ping; Chevrier, Vincent L.; Ceder, Gerbrand
DownloadOng-2011-Comparison of small.pdf (458.0Kb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
Using hybrid density functional theory based on the Heyd-Scuseria-Ernzerhof (HSE06) functional, we compared polaron migration and phase separation in olivine LiMnPO[subscript 4] to LiFePO[subscript 4]. The barriers for free hole and electron polaron migration in the Mn olivine system are calculated to be 303 and 196 meV, respectively, significantly higher than the corresponding barriers of 170 and 133 meV, respectively, for the Fe olivine system, in agreement with previous experimental findings. These results suggest that the electronic conductivities of LiMnPO4 and MnPO4 are about 177 and 11 times lower than their respective Fe analogs at room temperature. In the presence of lithium vacancies or ions, the barriers for both hole and electron polaron migration were found to be about 100–120 meV higher in the Mn olivine. The HSE06 functional, with its more universal treatment of self-interaction error, was found to be essential to the proper localization of a polaron in the Mn olivine but predicted qualitatively incorrect phase separation behavior in the LixFePO[subscript 4] system.
Date issued
2011-02Department
Massachusetts Institute of Technology. Department of Materials Science and EngineeringJournal
Physical Review B
Publisher
American Physical Society
Citation
Ong, Shyue Ping, Vincent L. Chevrier, and Gerbrand Ceder. “Comparison of Small Polaron Migration and Phase Separation in Olivine LiMnPO_{4} and LiFePO_{4} Using Hybrid Density Functional Theory.” Physical Review B 83.7 (2011) : 075112. ©2011 American Physical Society
Version: Final published version
ISSN
1098-0121
1550-235X