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Transport and Charge Carrier Chemistry in Lithium Sulfide
Author(s) -
Lorger Simon,
Usiskin Robert E.,
Maier Joachim
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201807688
Subject(s) - materials science , vacancy defect , passivation , charge carrier , dopant , lithium (medication) , electromotive force , chemical physics , doping , nanotechnology , chemistry , optoelectronics , crystallography , medicine , physics , layer (electronics) , quantum mechanics , endocrinology
Lithium sulfide is a functional material of great importance for battery research, since it is the discharge product in Li–S cathodes and a frequent component of anode passivation layers. In both cases, transport of charge carriers in Li 2 S is critical for performance. The exploration of charge carrier chemistry in such a simple binary compound is also of fundamental scientific interest. For that purpose, impedance spectroscopy and electromotive force measurements are performed over a broad range of temperatures and doping conditions. The results indicate predominant ion conduction and can be quantitatively explained by a defect chemical model based on Frenkel disorder and vacancy‐dopant association. Mobilities and migration barriers for both vacancy and interstitial defects are deduced. The thermodynamic and kinetic parameters derived for Li + transport in antifluorite Li 2 S show remarkable agreement with the analogous parameters for F − transport in fluorite compounds such as BaF 2 , thereby improving the structural understanding of charge carrier chemistry in such compounds. An application of these results to passivation layers in solid state batteries is also discussed.