Neutron diffraction study of Li4Ti5O12 at low temperatures

• Crystal structure of Li4Ti5O12 was studied by neutron diffraction in a temperature range 3.4 K–300 K.
• No phase transition was detected, and the thermal evolution of lattice parameters was evaluated.
• Different behavior of bond lengths in tetrahedral and octahedral oxygen coordinations was found.
• The bond-valence modeling of Li4Ti5O12 revealed Li diffusion in a 8a-32e-32e-8a pathway.

The crystal structure of the “zero-strain” positive electrode material Li4Ti5O12 was characterized by neutron powder diffraction in the temperature range 3.4 K–300 K. No phase transition was detected, and the thermal evolution of lattice parameters has been evaluated by the 2nd order Grüneisen approximation using the Debye formalism for internal energy and intrinsic anharmonicity contributions. A relatively high Debye temperature θD = 689 ± 71 K was determined. The thermal behavior of cation-anion bond lengths in octahedral and tetrahedral environments is discussed. The lithium diffusion pathway in Li4Ti5O12 was discussed on the basis of bond-valence modeling.

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