Laumann, Andreas Boysen, Hans Bremholm, Martin Fehr, K. Thomas Hoelzel, Markus Holzapfel, Michael Lithium Migration at High Temperatures in Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> Studied by Neutron Diffraction The structure of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> was investigated by neutron powder diffraction, and the study revealed unprecedented details about lithium migration at high temperatures. A commercial sample of the battery anode material Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> (spinel-type) was measured from room temperature to 1100 °C. Up to 500 °C, linearly increasing values for the unit cell parameter, the isotropic atomic displacement parameters, and the oxygen position are observed. At 700 °C, a change of slope occurs, which is assigned to the beginning migration of lithium. Previous investigations identified the octahedral 16c site in the spinel structure as the migration position of lithium upon heating to high temperatures, and because of that, several phase transitions of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> at high temperatures have been proposed. Here, we unambiguously identify that the lithium atoms occupy split sites around the 16c positions and order–disorder phase transitions of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> were not observed. One-particle potential shows that the occupancy of 16c is an unstable configuration and that the split-site structure leads to a more favorable migration position. Occupation of the lithium sites (32e) results in the same long-range diffusion path in all ⟨110⟩ directions. The onset of lithium migration can explain the change of the ionic conductivity of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> at high temperatures, which has been observed by impedance spectroscopic studies. Further heating to 1000 °C resulted in a partial decomposition of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> into the ramsdellite-type Li<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> and the cubic γ-Li<sub>2</sub>TiO<sub>3</sub>, and at 1100 °C, the Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> spinel was fully decomposed. octahedral 16 c site;neutron powder diffraction;migration position;Li 4Ti spinel;unit cell parameter;Li 4Ti Studied;Li 4Ti;lithium migration;Neutron DiffractionThe structure;16 c positions;battery anode material Li 4Ti;impedance spectroscopic studies 2011-06-14
    https://acs.figshare.com/articles/dataset/Lithium_Migration_at_High_Temperatures_in_Li_sub_4_sub_Ti_sub_5_sub_O_sub_12_sub_Studied_by_Neutron_Diffraction/2642509
10.1021/cm103332y.s007