Pitch carbon-coated lithium sulfide electrode for advanced, lithium-metal free-sulfur batteries

Abstract

In this work we report the properties and characteristics of a pitch carbon-coated lithium sulfide material. We show that this material behaves as a very promising electrode in liquid glyme-based and in solid poly(ethylene oxide) PEO-based electrolyte lithium cells. Particular relevant is the response obtained in the solid-state configuration where a capacity approaching the theoretical value of the full Li2S conversion process, i.e. 1200 mAh gLi2S-1 is obtained at a C/10 rate with no signature of ohmic polarization. The solid-state cell cycles at a C/3 rate with a stable capacity of 500 mAh gLi2 S-1, i.e., a value about three times higher than that offered by conventional intercalation lithium metal oxide electrodes. This unique performance makes the pitch carbon-coated lithium sulfide electrode a good candidate for the development of high energy density, lithium-metal free-sulfur superbatteries to be addressed to the electric vehicle market.