Vaporization property and crystal structure of lithium metatitanate with excess Li

Point Defects and Non-stoichiometry in Li2TiO3

“…Excess Li 2 O is accommodated in the crystal by Li i 1+ defects charge compensated for by either electrons or Li Ti 3– defects depending on the oxygen partial pressure. Conduction electrons are expected to localize on titanium atoms, reducing them to the Ti 3+ charge state, as has been predicted on the basis of experimental observations. , By contrast, excess TiO 2 will be accommodated by mutually charge-compensating V Li 1– and Ti Li 3+ defects, in good agreement with experiment, except at low oxygen partial pressures where the defect chemistry is dominated by Ti antisite defects charge-compensated by conduction electrons.…”

“…Conduction electrons are expected to localize on titanium atoms, reducing them to the Ti 3+ charge state, as has been predicted on the basis of experimental observations. 10,8 By contrast, excess TiO 2 will be accommodated by mutually charge-compensating V Li 1− and Ti Li 3+ defects, in good agreement with experiment, except at low oxygen partial pressures where the defect chemistry is dominated by Ti antisite defects charge-compensated by conduction electrons. The limiting step to tritium extraction in solid breeder materials is diffusion to the surface of the pebble.…”

“…7 Mukai et al interpreted their neutron diffraction data to suggest that the excess lithium is accommodated at either interstitial sites or as Li Ti 3− antisite defects with the resulting charge compensated for by the reduction of Ti or site vacancies, i.e., Li 2+x Ti 1−x 3+ Ti x 4+ O 3 or Li 2+2x Ti 1−x O 3−x . 8 Substitution of Li for Ti (i.e., Li Ti −3 ) was also observed by Vitins et al in samples containing a slight Li-excess at temperatures in the range 770−850 °C analyzed using scattered reflectance spectroscopy. 9 Hoshino et al show that upon heating Li 2 TiO 3 in a reducing atmosphere the color of their sample changed from white to dark blue, suggesting that an oxygen deficiency is accommodated by V O 2+ defects compensated for by reduced Ti 3+ cations.…”

“…The proposed formation of V Ti 4– defects with V O 2+ for x < 0.2 is also proposed by Bian and Dong on the basis of XRD supported in this case by Raman spectra . Mukai et al interpreted their neutron diffraction data to suggest that the excess lithium is accommodated at either interstitial sites or as Li Ti 3– antisite defects with the resulting charge compensated for by the reduction of Ti or site vacancies, i.e., Li 2+ x Ti 1– x 3+ Ti x 4+ O 3 or Li 2+2 x Ti 1– x O 3– x . Substitution of Li for Ti (i.e., Li Ti –3 ) was also observed by Vitins et al in samples containing a slight Li-excess at temperatures in the range 770–850 °C analyzed using scattered reflectance spectroscopy .…”

Lithium Vapor Chemistry of Hyper-Stoichiometric Lithium Metatitanate Li2.12(2)TiO3+y

“…19 It is noteworthy that mass loss by evaporation of Li-containing species at high temperatures were enhanced by the increase of Li/Ti ratio. 20,21 The Li loss by evaporation should be minimized for sufficient breeding of tritium fuel during reactor operation. Additionally, the vaporization behavior affects chemical compatibility between ceramic breeder and reduced-activation ferritic/martensitic (RAFM) steels; the Li-containing gaseous species are corrosive and form a double oxide layer on surface of the RAFM steels, [22][23][24][25] in which the growth is controlled by oxygen diffusion in the layers.…”