▎ 摘　　要

Establishing the efficient electronic conductivity of a sulfur cathode without compromising the volumetric energy density and confining dissolved polysulfides within the cathode of the cell are first-order research priorities in the area of Li-S batteries. The emerging nanotechnology-based approaches, especially the use of porous nanocarbon in the formation of the sulfur electrode, stand to negatively affect the volumetric energy due to the low tap-density of C-S cathodes. In order to address these issues, we study the effects of the porosity and density of different carbons such as graphite, graphene and graphite-graphene hybrids on the overall volumetric capacity of the electrode. Although graphene-sulfur (GS) and graphene-decorated graphite-sulfur (GGS) electrodes show similar gravimetric capacities (similar to 1050 mA h g(-1)), the GGS electrode exhibits a high volumetric capacity (745 mA h cm(-3)) without compromising the electrochemical stability over 50 cycles. Furthermore, an excellent cycle stability of the GGS electrode over 100 cycles is achieved by coating a thin layer of poly(methyl methacrylate) (PMMA) on the GGS electrode. Maintaining a high tap-density along with porosity is key in achieving high volumetric capacity in C-S cathodes.