Synthesis and Characterization of Graphene Oxide/Sulfur Nanocomposite for Lithium-Ion Batteries

The growing need for clean and efficient energy storage systems has recently peaked due to concerns of climate change and increased global energy consumption. However, efficiently integrating renewable resources such as solar and wind energy into society will require a complex electrical energy storage (EES) system capable of storing and expending significant amounts of energy. A battery based on the lithium/sulfur couple can yield a theoretical specific energy of 2600Wh/kg, which is about five times higher than that offered by present Li-ion batteries, and hence, is a promising and attractive technology. Despite recent developments in addressing various issues inherent to a sulfur cathode, the lithium/sulfur couple continues to exhibit capacity fade over cycling. The present study uses a low cost, solution-based reaction to heterogeneously nucleate and grow sulfur within the graphene oxide (GO) matrix. The reactive functional groups on GO work to entrap sulfur, thereby reducing polysulfide dissolution and improving electrochemical stability. Morphologies, compositions, and structures of the as-prepared GO/S nanocomposites were characterized using SEM, XRD, TGA, DSC, and EDX. Performance characteristics were electrochemically determined via discharge/charge cycling, and were compared against mechanically mixed GO/S composites. The optimized GO/S nanocomposite was then combined with a graphene-based anode, forming a novel Li-ion/S cell configuration. The replacement of the metallic lithium anode is anticipated to overcome numerous issues afflicting the Li/S battery concept. It is found that selection of an electrolyte compatible with both GO anode and GO/S cathode is critically important to achieve better performance for a graphene-based Li-ion/S cell, which is subjected to further studies