Recent literature  [1,2,3,4] reports the use of Li₄SnS₄ and its alloys as a relatively stable solid electrolyte for use in all-solid-state Li batteries. This poster presents results of first-principles simulations of the ideal crystalline structures and of defects associated with Li ion migration in this material.    The simulations find that the lowest energy
structure of the idealized crystal is consistent with the structure determined by MacNeil et at. [2] from samples synthesized at high temperature (750 deg C). The simulations also find  a slightly higher energy structure which is consistent with the structure determined by  Kaib et al. [1] from samples prepared at lower temperature (320 deg C), processed from solution. Simulations of the Li ion migration properties of the two structures are compared.

Acknowledgements
This work was supported by NSF grant DMR-1507942 and by the Wake Forest University DEAC Computer Cluster.  Joseph MacNeil and Jennifer Aitken  contributed additional information about the experimental details.

[1]Thomas Kaib, Sima Haddadpour, Mauel Kapitein, Philipp Bron, Cornelia Schroeder, Hellmut Eckert, Bernard Roling, and Stefanie Dehenen, Chemistry of Materials, 24, 2211-2219 (2012)

[2]Joseph H. MacNeil, Danielle M. Massi, Jian-Han Zhang, Kimberly A. Rosmus, Carl D. Brunetta, Taylor A. Gentile, and Jennifer A. Aitken, Journal of Alloys and Compounds, 586, 736-744 (2014)

[3] Gayatri Sahu, Zhan Lin, Juchuan Li, Zencai Liu, Nancy Dudney, and Chengdu Liang, Energy & Environmental Science, 7, 1053-1058 (2014)

[4] Kern Ho Park, Dae Yang Oh, Young Eun Choi, Young Jin Nam, Lili Han, Ju-Young Kim, Huolin Xin, Feng Lin, Seung M. Oh, and Yoon Seok Jung, Advanced Materials,  DOI: 10.1002/adma.201505008