(286c) Sulfur Encapsulated in Carbon Hollow Structures as Positive Electrodes for Lithium-Sulfur Batteries

Rechargeable batteries with high energy density are essential for emerging demands such as electric vehicles. Lithium-sulfur batteries hold great promise to achieving high energy density due to the high specific capacity of sulfur (1675 mAh g-1) as a cathode material. However, there have been two major challenges for the realization of Li-S batteries: one is the low electrical conductivity of the sulfur, and the other is the formation of polysulfides through charge/discharge cycles. The low conductivity leads to poor rate performance and low utilization of active materials. The formed polysulfides are dissolvable in the liquid electrolyte thus resulting in very fast complete loss of capacity. In the present study, we attempt to solve these two problems by encapsulation sulfur into hollow carbon structures including carbon tubes synthesized with anodic aluminum oxide (AAO) template method, hollow carbon nanofibers from electrospin technique, and hollow carbon spherical structures using emulsion polymerization with various templates.