Nuclear magnetic resonance studies of BH4 reorientations and Li diffusion in LiLa(BH4)3Cl

Skripov, A.V.;Soloninin, A.V.;Ley, M.B.;Jensen, T.R.;Filinchuk, Yaroslav
(2013) Journal of Physical Chemistry C — Vol. 117, n° 29, p. 14965-14972 (2013)

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Authors
  • Skripov, A.V.Ural Division of the Russian Academy of Sciences (Russia)
    Author
  • Soloninin, A.V.Ural Division of the Russian Academy of Sciences (Russia)
    Author
  • Ley, M.B.Aarhus University (Denmark)
    Author
  • Jensen, T.R.Aarhus University (Denmark)
    Author
  • Author
Abstract
To study the reorientational motion of BH4 groups and the translational diffusion of Li+ ions in the novel bimetallic borohydride chloride LiLa(BH4)3Cl, we have measured the 1H, 11B, and 7Li NMR spectra and spin-lattice relaxation rates in this compound over the temperature range of 23-418 K. At low temperatures (T < 110 K), the proton spin-lattice relaxation rates are governed by fast reorientations of BH4 groups. This reorientational process can be satisfactorily described in terms of a two-peak distribution of the activation energies with the peak Ea values of 41 and 50 meV. Above 200 K, the NMR data are governed by a combined effect of two types of motion occurring at the same frequency scale: Li ion diffusion and another (slower) reorientational motion of BH4 groups. These results suggest that the Li ion jumps and the slower reorientational jumps of BH4 groups in LiLa(BH4)3Cl may be correlated. The estimate of the tracer Li ion diffusion coefficient at room temperature (5.2 × 10 -8 cm2/s) following from our experimental data indicates that LiLa(BH4)3Cl can be considered as a promising solid-state ionic conductor. © 2013 American Chemical Society.
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Citations

Skripov, A. V., Soloninin, A. V., Ley, M. B., Jensen, T. R., & Filinchuk, Y. (2013). Nuclear magnetic resonance studies of BH4 reorientations and Li diffusion in LiLa(BH4)3Cl. Journal of Physical Chemistry C, 117(29), 14965-14972. https://doi.org/10.1021/jp403746m (Original work published 2013)