Please use this identifier to cite or link to this item: http://dx.doi.org/10.14279/depositonce-5481
|Main Title:||Lithium diffusion pathways in 3R-LixTiS2: a combined neutron diffraction and computational study|
Islam, Mazharul M.
|Abstract:||Layered lithium transition-metal sulfides have long been discussed as early electrode materials for lithium-ion batteries. However, fundamental knowledge of lithium-ion migration in these solids is still lacking. In this study, we report on the diffusion dynamics in lithium-deficient high-temperature polymorphs of lithium titanium sulfides (3R-LixTiS2; x = 0.7, 0.9) as analyzed using powder neutron diffractometry and density functional theory (DFT) climbing-image nudged-elastic-band (cNEB) calculations. Two classes of probable migration pathways have been identified from the scattering-length density distributions (filtered using the maximum-entropy method [MEM]) and the probability density functions (PDFs, modeled from anharmonic Debye-Waller factors): direct diffusion in the (001) plane as the major mechanism and indirect diffusion through adjacent tetrahedral voids as a minor mechanism. Calculated activation barriers agree well with one-particle potentials (OPPs) derived from measurements for Li0.7TiS2 (0.484 and 0.88 eV) but deviate for Li0.9TiS2. The discrepancy at low defect concentration is attributed to the failure of the OPP derivation and the different nature of the methods (space-time averaged vs individual-ion perspective). This work elucidates the pathways of lithium-ion diffusion in 3R-LixTiS2 and points out pitfalls in established experimental/computational methods.|
|DDC Class:||540 Chemie|
|Sponsor/Funder:||DFG, FOR 1277, Mobilität von Lithiumionen in Festkörpern (molife)|
|Open Content License:||http://pubs.acs.org/page/policy/authorchoice_termsofuse.html|
|Journal Title:||Journal of Physical Chemistry C|
|Publisher:||American Chemical Society|
|Publisher Place:||Washington, D.C.|
|Appears in Collections:||Fachgebiet Anorganische Chemie - Festkörper- und Materialchemie » Publications|
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