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Atomistic simulation studies of nanostructural titanium dioxide and its lithiationMatshaba, Malili Gideon. January 2013 (has links)
Thesis (P.hD (Physics)) --University of Limpopo, 2013 / Titanium dioxide (TiO2) nanoparticles, nanowires, nanosheets and nanoporous are of
great interest in many applications. This is due to inexpensive, safety and rate capability
of the material. It has being considered as a replacement of graphite anode material in
rechargeable lithium batteries. Much experimental work on pure and lithiated
nanostructures of TiO2 has been reported, mostly with regards to their complex
microstructures. In this work we employ molecular dynamics (MD) simulation to
generate models of TiO2 nano-architectures including: nanosheet, nanoporous,
nanosphere and bulk. We have successfully recrystallised all four nanostructures from
amorphous precursors; calculated radial distribution functions (RDFs), were used to
confirm crystallinity. Configuration energies, calculated as a function of time, were used
to monitor the recrystallisation. Calculated X-Ray Diffraction (XRD) spectra, using the
model nanostructures, reveal that the nanostructures are polymorphic with TiO2 domains
of both rutile and brookite in accord with experiment.
Amorphisation and recrystallisation was successful in generating complex
microstructures. In particular, bulk and nanoporous structures show zigzag tunnels
(indicative of micro-twinning) while nanosphere and nanosheet shows zigzag and straight
tunnels in accord with experiment. All model nanostructures of TiO2 were lithiated with
different lithium content. RDFs, microstructures, configuration energies, calculated as a
function of time and XRDs of all lithiated structures are presented. / University of Limpopo Research Office,The Royal Institution(Ri),Granfield University,Materials Modelling Centre,UCL,and the CHPC
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