Abstract
Layered LiMnO2 is a potential Li ion cathode material that is known to undergo a layered to spinel transformation upon delithiation, as a result of Mn migration. A common strategy to improve the structural stability of LiMnO2 has been to replace Mn with a range of metal dopants, although the mechanism by which each dopant stabilizes the structure is not well understood. In this work we characterize ion-migration barriers using hybrid eigenvector-following (EF) and density functional theory to study how trivalent dopants (Al3+, Cr3+, Fe3+, Ga3+, Sc3+, and In3+) affect Mn migration during the initial stage of the layered to spinel transformation in Li0.5MnO2. We demonstrate that dopants with small ionic radii, such as Al3+ and Cr3+, can increase the barrier for migration, but only when they are located in the first cation coordination sphere of Mn. We also demonstrate how the hybrid EF approach can be used to study the migration barriers of dopant species within the structure of Li0.5MnO2 efficiently. The transition state searching methodology described in this work will be useful for studying the effects of dopants on structural transformation mechanisms in a wide range of technologically interesting energy materials.
Original language | English |
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Pages (from-to) | 19521-19530 |
Number of pages | 10 |
Journal | Journal of Physical Chemistry C |
Volume | 120 |
Issue number | 35 |
Early online date | 19 Aug 2016 |
DOIs | |
Publication status | Published - 8 Sept 2016 |
Bibliographical note
Funding Information:this work used the ARCHER UK National Supercomputing Service. Research was also carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-98CH10886. C.P.G. acknowledges the NorthEast Center for Chemical Energy Storage (NECCES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award #DE-SC0012583. I.D.S. acknowledges funding from NECCES and the Geoffrey Moorhouse Gibson Studentship in Chemistry from Trinity College Cambridge
Publisher Copyright:
© 2016 American Chemical Society.