Based on the new ab initio molecular dynamics method by Kühne et al. [Phys. Rev. Lett. 98, 066401 (2007)], we studied the mechanism of superionic conduction in substoichiometric Li-poor Li1+xAl alloys by performing simulations at different temperatures for an overall simulation time of about 1 ns. The dynamical simulations revealed the microscopic path for the diffusion of Li vacancies. The calculated activation energy (0.11 eV) and the prefactor (D0=6.9×10-4 cm2/s) for Li diffusivity via a vacancy-mediated mechanism are in good agreement with experimental NMR data. The calculation of the formation energies of different defects—Li and Al Frenkel pair and Li antisites—revealed that only Li+ vacancies and LiAl antisites are present in the stability range of the Zintl phase -0.1<0.2
Cucinotta, C., Miceli, G., Raiteri, P., Krack, M., Kuehne, T., Bernasconi, M., et al. (2009). Superionic Conduction in Substoichiometric LiAl Alloy: An Ab Initio Study. PHYSICAL REVIEW LETTERS, 103(12) [10.1103/PhysRevLett.103.125901].
Superionic Conduction in Substoichiometric LiAl Alloy: An Ab Initio Study
BERNASCONI, MARCO;
2009
Abstract
Based on the new ab initio molecular dynamics method by Kühne et al. [Phys. Rev. Lett. 98, 066401 (2007)], we studied the mechanism of superionic conduction in substoichiometric Li-poor Li1+xAl alloys by performing simulations at different temperatures for an overall simulation time of about 1 ns. The dynamical simulations revealed the microscopic path for the diffusion of Li vacancies. The calculated activation energy (0.11 eV) and the prefactor (D0=6.9×10-4 cm2/s) for Li diffusivity via a vacancy-mediated mechanism are in good agreement with experimental NMR data. The calculation of the formation energies of different defects—Li and Al Frenkel pair and Li antisites—revealed that only Li+ vacancies and LiAl antisites are present in the stability range of the Zintl phase -0.1<0.2
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