Synthesis of reduced graphene oxide for use as an additive in Li-S battery cathodes

Abstract

Lithium-sulfur (Li-S) batteries have been considered as the next-generation battery technology due to their high energy density, abundance, and environmental friendliness. However, the low electrical and ionic conductivity of sulfur limits its use as an electrode. The main problem encountered is the high solubility of long-chain polysulfides, which are intermediates in electrochemical processes, in the liquid electrolyte. Dissolved polysulfide ions travel between the anode and cathode, leading to the precipitation of the Li2S2/Li2S insulator on the electrode surface. This phenomenon results in the loss of both active material and capacity. It has been observed that sulfur-based composite materials integrated with carbon materials, such as reduced graphene oxide (rGO) have proven to be effective in improving the electrochemical performance of the sulfur cathode. For this reason, the objective of this work is to synthesize -rGO from coke coal and evaluate the reduction process by two methods: chemical and mechanical.