Superionic Conduction in Substoichiometric LiAl Alloy: An Ab Initio Study

被引:19
作者
Cucinotta, Clotilde S. [1 ]
Miceli, Giacomo [1 ]
Raiteri, Paolo [1 ]
Krack, Matthias [1 ]
Kuehne, Thomas D. [1 ]
Bernasconi, Marco [2 ]
Parrinello, Michele [1 ]
机构
[1] Swiss Fed Inst Technol, Computat Sci Dept Chem & Appl Biosci, LUI, CH-6900 Lugano, Switzerland
[2] Univ Milano Bicocca, Dipartimento Sci Mat, I-20125 Milan, Italy
关键词
SELF-DIFFUSION; NMR; PSEUDOPOTENTIALS;
D O I
10.1103/PhysRevLett.103.125901
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Based on the new ab initio molecular dynamics method by Kuumlhne et al. [Phys. Rev. Lett. 98, 066401 (2007)], we studied the mechanism of superionic conduction in substoichiometric Li-poor Li(1+x)Al 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 (D(0)=6.9x10(-4) cm(2)/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 Li(Al) antisites are present in the stability range of the Zintl phase -0.1 < x < 0.2.
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页数:4
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