LixTiO2-B nanowires (0 < x ≤ 0.9) were studied as anode materials in secondary Li-ion batteries. The Li self-diffusion parameters in mixed conducting nanowires with the composition Li0.3TiO2 were directly determined by mixing time (tm)-dependent two-time 7Li spin-alignment echo nuclear-magnetic-resonance correlation spectroscopy between 330 and 500K. Spin-alignment echo nuclear-magnetic-resonance revealed extremely slow Li self-diffusion processes in LixTiO2-B. Li jump rates τ−1 ranged from 5 to 2.5 x 103/s. The corresponding hopping correlation functions F2 could be well described by stretched exponentials, F2 ∝ exp[−(t/tm)γ], with γ = 0.35; independent of temperature. The influence of spin-diffusion effects upon the echo amplitude was elaborated by evolution time-dependent 7Li spin-alignment echo nuclear-magnetic-resonance experiments. The results were compared with those obtained by using conventional 7Li nuclear-magnetic-resonance spin-lattice relaxation measurements.

Li Diffusion Properties of Mixed Conducting TiO2-B Nanowires. Wilkening, M., Heine, J., Lyness, C., Armstrong, A.R., Bruce, P.G.: Physical Review B, 2009, 80[6], 064302