The properties and structure of the lithium ion-conducting oxysulfide glass
es in the systems Li2S-SiS2-LichiMOgamma (LichiMOgamma: lithium ortho-oxosa
lt, M = Si, P, Ge, B, Al, Ga and In) are reviewed. The Li2S-SiS2 glass adde
d with small amounts of LichiMOgamma exhibited high glass stability against
crystallization, high conductivity of 10(-3) S cm(-1) at room temperature,
and wide electrochemical window. Further addition of Li-chi,MOgamma reduce
d these superior properties in any system. High-resolution solid-state NMR
and X-ray photoelectron spectroscopy revealed that the silicon atoms coordi
nated with both bridging oxygen atoms and nonbridging sulfur atoms were mai
nly present in the glasses with small amounts of LichiMOgamma. The presence
of these unique structural units brought about high conductivities and hig
h thermal stability of these glasses. The solid state battery with the oxys
ulfide glass worked as a lithium secondary battery and performed excellent
cycling behaviors. (C) 2000 Elsevier Science B.V. All rights reserved.