Structure Prediction of Li–Sn and Li–Sb Intermetallics for Lithium-Ion Batteries Anodes

4 years ago

Structure Prediction of Li–Sn and Li–Sb Intermetallics for Lithium-Ion Batteries Anodes

Andrew J. Morris, Martin Mayo

A variety of new stable and metastable Li–Sn and Li–Sb intermetallics are presented using the ab initio random structure searching (AIRSS) and species swapping methods. These include LiSn₂–P4/mmm, Li₂Sn₃–P1̅, Li₇Sn₉–P4₂/n, Li₃Sn₂–P2₁/m, Li₅Sn₃–Im3̅m, Li₂Sn–Cmcm, Li₈Sn₃–R3̅m, Li₃Sn–P3₂, Li₇Sn₂– P1̅, Li₄Sn–P2₁, Li₅Sn–P6/mmm, Li₇Sn–Fmmm, LiSb–P4/mmm, Li₈Sb₅–Fd3̅m, Li₈Sb₃–P2/c, Li₄Sb–C2/m, Li₉Sb₂–P3̅m₁, Li₅Sb–P6/mmm, Li₆Sb–R3̅m, Li₈Sb–Pc, and Li₉Sb–Cmcm. The Li–Sn theoretical voltage curve was calculated to high accuracy mainly from experimentally known structures and shows excellent agreement with experimental electrochemical cycling measurements previously reported. Li₂Sn was found on the convex hull to within density-functional theory accuracy, and its mechanical stability was investigated by calculating the density of states of the phonon spectrum. The new structures obtained by AIRSS show a consistent structural evolution of Li–Sn phases as Li concentration is increased. First-principles NMR calculations on the hexagonal and cubic Li₃Sb phases are performed. Our NMR results are compared to findings of Johnston et al. (Chem. Mater. 2016, 28, 4032) and proposed as a diagnostic tool to interpret experimental data.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.6b04914

DOI: 10.1021/acs.chemmater.6b04914