Lithium sulfide
= Lithium sulfide
{title2=$\mathrm{Li_2S}$}
<Lithium sulfide> is $\mathrm{Li_2S}$, with lithium cations and sulfide anions. Sulfur has the formal oxidation state −2 in this composition.
Oxidation of sulfide toward elemental <sulfur> connects <lithium sulfide> with the chemistry of lithium-sulfur batteries. The transformation changes both oxidation state and solid-phase composition, so charge transport and material redistribution affect practical behaviour.