Low Voltage Behavior of Lithium/Metal Dichalcogenide Topochemical Cells

The formation of in Li/Li + , propylene carbonate cells occurs near 1.0V. The selenide, , has been previously described. Magnetic susceptibility and x‐ray powder diffraction data are presented for . The couples are reversible and two phase between the limiting compositions. The selenide is reversible over the range to , but the sulfide deteriorates if not confined to the couple. has a similar voltage profile near 0.5V assigned to the couple, which appears to be reversible, but is accompanied by either side reaction with the electrolyte or slow decomposition of .