Regensburg 2007 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 11: Poster Session

DF 11.31: Poster

Thursday, March 29, 2007, 14:30–18:00, Poster C

Li diffusion in the intercalated anode material Li_4+xTi₅O₁₂ with x > 0 — •Wojciech Iwaniak¹, Martin Wilkening¹, Jessica Heine¹, Viktor Epp¹, Paul Heitjans¹, Malte Behrens², and Wolfgang Bensch² — ¹Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover — ²Institute of Inorganic Chemistry, Christian-Albrechts University Kiel

Currently there is considerable interest in spinel-type structured Li_4+xTi₅O₁₂ (0 ≤ x ≤ 3, space group Fd3m) as a future anode in secondary Li ion batteries. Whereas the host material with x=0 is a poor Li conductor [1], the intercalated compounds with 0 < x < 3 show enhanced Li diffusivity. Additional Li can be inserted into Li₄Ti₅O₁₂ either chemically by treatment with n-butyl lithium or electrochemically. Diffusion parameters were studied by ⁷Li spin-alignment echo (SAE) NMR as well as by ⁷Li rotating frame spin-lattice relaxation NMR. Activation energies E_A of Li diffusion in the intercalated materials prepared by both routes are similar. Compared to the non-intercalated host E_A is reduced by about a factor of two. In the host (x = 0) an activation energy of 0.86(1) eV was recently found by SAE-NMR, see Ref. [1]. NMR results will be compared with data obtained by dc-conductivity measurements.

[1] M. Wilkening, R. Amade, W. Iwaniak and P. Heitjans, Phys. Chem. Chem. Phys., 2007, DOI:10.1039/b616269j, in press.