Phase stability, electrochemical stability and ionic conductivity of the Li[subscript 10±1]MP[subscript 2]X[subscript 12] (M = Ge, Si, Sn, Al or P, and X = O, S or Se) family of superionic conductors
Author(s)
Ong, Shyue Ping
Mo, Yifei
Richards, William Davidson
Miara, Lincoln
Lee, Hyo Sug
Ceder, Gerbrand
Date Issued
October 2012
Journal
Energy & Environmental Science
Publisher
Royal Society of Chemistry, The
Citation
Ong, Shyue Ping, Yifei Mo, William Davidson Richards, Lincoln Miara, Hyo Sug Lee, and Gerbrand Ceder. “Phase stability, electrochemical stability and ionic conductivity of the Li10±1MP2X12 (M = Ge, Si, Sn, Al or P, and X = O, S or Se) family of superionic conductors.” Energy & Environmental Science 6, no. 1 (2012): 148.
Version
Author's final manuscript
Abstract
We present an investigation of the phase stability, electrochemical stability and Li[superscript +] conductivity of the Li[subscript 10±1]MP[subscript 2]X[subscript 12] (M = Ge, Si, Sn, Al or P, and X = O, S or Se) family of superionic conductors using first principles calculations. The Li[subscript 10]GeP[subscript 2]S[subscript 12] (LGPS) superionic conductor has the highest Li[superscript +] conductivity reported to date, with excellent electrochemical performance demonstrated in a Li-ion rechargeable battery. Our results show that isovalent cation substitutions of Ge[superscript 4+] have a small effect on the relevant intrinsic properties, with Li[subscript 10]SiP[subscript 2]S[subscript 12] and Li[subscript 10]SnP[subscript 2]S[subscript 12] having similar phase stability, electrochemical stability and Li[superscript +] conductivity as LGPS. Aliovalent cation substitutions (M = Al or P) with compensating changes in the Li[superscript +] concentration also have a small effect on the Li[superscript +] conductivity in this structure. Anion substitutions, however, have a much larger effect on these properties. The oxygen-substituted Li[subscript 10]MP[subscript 2]O[subscript 12] compounds are predicted not to be stable (with equilibrium decomposition energies >90 meV per atom) and have much lower Li[superscript +] conductivities than their sulfide counterparts. The selenium-substituted Li[subscript 10]MP[subscript 2]Se[subscript 12] compounds, on the other hand, show a marginal improvement in conductivity, but at the expense of reduced electrochemical stability. We also studied the effect of lattice parameter changes on the Li[superscript +] conductivity and found the same asymmetry in behavior between increases and decreases in the lattice parameters, i.e., decreases in the lattice parameters lower the Li[superscript +] conductivity significantly, while increases in the lattice parameters increase the Li[superscript +] conductivity only marginally. Based on these results, we conclude that the size of the S[superscript 2−] is near optimal for Li[superscript +] conduction in this structural framework.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike 3.0
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1039/c2ee23355j
