The lithium–sulfur chemistry is regarded as a promising candidate for next-generation battery systems because of its high specific energy (1675 mAhg^-1). Although issues such as the low cycle stability and power capability of the system remain to be addressed, extensive research has been performed experimentally to resolve these problems. Attaining a fundamental understanding of the reaction mechanism and its reaction product would further spur the development of lithium–sulfur batteries. Here, we investigated the charge transport mechanism of lithium sulfide (Li₂S), a discharge product of conventional lithium-sulfur batteries using first-principles calculations. Our calculations indicate that the major charge transport is governed by the lithium-ion vacancies among various possible charge carriers. Furthermore, the large bandgap and low concentration of electron polarons indicates that the electronic conduction negligibly contributes to the charge transport mechanism in Li₂S