The ultra-high volumetric energy density lithium-sulfur battery
Lithium ion battery technology (LIBs) is one of the most important mobile power sources for laptops, cameras, and smart phones. However, the current energy density of LIBs is approaching the theoretical limit, which underscoring the urgent need for new high energy density battery systems. Among the high-energy density storage systems, lithium-sulfur batteries, with energy density of 2600 Wh kg-1 (nearly 3~5 times than that of the traditional LIBs), holds the potential to serve as next generation of high energy battery. Sulfur possesses a very low electric conductivity of 5x10-30 S cm-1 at room temperature. Therefore, 30-70 wt. percent conductive materials, e.g. carbon nanotubes, graphene, porous carbon, and conductive polymers, have to be added into the electrode for high utilization of sulfur at current processing technology. The addition of nanocarbon materials with low stacking density neutralizes the high energy density, especially the volumetric energy density of lithium-sulfur batteries.