High-Sulfur-Content Graphene-Based Composite through Ethanol Evaporation for High-Energy Lithium-Sulfur Battery.

Lithium-sulfur batteries are the most promising candidates for next-generation energy storage devices owing to their high theoretical specific capacity of 1675 mAh g-1 and high theoretical energy density of approximately 3500 Wh kg-1 . However, the lack of cathode active materials with appropriate electrical conductivities and stability coupled with an inexpensive and industrially compatible production process has so far hindered the development of practical devices. Here, a facile preparation pathway is reported for the production of a sulfur-carbon composite active material by drying a mixture of highly conductive few-layer graphene (FLG) flakes (produced by exploiting an innovative wet jet milling process with a yield of ≈100 % and production capability of ≈23.5 g h-1 ) with elemental sulfur, using ethanol as an environmentally friendly solvent. The designed sulfur-FLG composite shows excellent electrochemical results. The assembled lithium-sulfur battery exhibits a stable rate capability up to a current rate of 2C, a coulombic efficiency approaching 100 % for 300 cycles at the current rate of C/4 (420 mA g-1 ), and a long cycle life up to 500 cycles delivering around 600 mAh g-1 at 2C (3350 mA g-1 ).