Novel energy storage systems with high energy density and reduced cost has drawn significant attention due to the emerging storage application, such as commercial electronic devices, electrical vehicles, and grid storage systems. Conventional Li-ion batteries, however, are hard to meet the requirement for those applications in near future due to the theoretical energy density limit. Therefore, advanced batteries with different chemistry which could provide higher capacity and energy density are necessary for further development. Among many candidates, Lithium-sulfur battery (Li-S) has been recognized as one promising system due to its high gravimetric energy density and low material cost, which is superior to most of current Li-ion batteries. Besides sulfur, selenium (Se) has also been involved in the battery study, since it shares similar lithiation/delithiation mechanism to sulfur. In addition, although with lower gravimetric capacity than sulfur, the better electrical conductivity and less shuttling behavior make selenium parallel path of the sulfur system.

Due to their dissolution nature of both Li-S and Li-Se systems, supporting materials which provide a robust framework with sufficient internal space and reactive sites, are critical for the chemistry. Although there were many candidates for the supporting material in Li-S and Li-Se batteries, such as metal oxides and graphene based materials, porous carbon materials are still dominant for a practical point of view. Relatively low cost, Industrial scale production and convenient handling make porous carbon materials superior to other supporting materials. Here we present a summary of our work on several porous carbon materials as the supporting material, which help enable high S/Se loading on both material level and electrode level, for the Li-S and Li-Se batteries. We will demonstrate the preparation, characterization and electrochemical performance of the carbon materials. The comparison of corresponding Li-S and Li-Se will be also described. Besides carbon materials, we will also discuss about our study on the influence of polymer binder and electrolyte on the optimized electrodes on both Li-S and Li-Se systems. Further discussions on the battery design and cell-level energy density estimation will be also addressed.