Biomass-derived Activated Carbon for Rechargeable Lithium-Sulfur Batteries

High-surface-area activated carbon (HSAAC) was synthesized by carbonizing coconut shells and subsequently activating the material with KOH. The as-prepared HSAAC had a mostly microporous structure (with small mesoporous inclusions) and exhibited a high specific surface area of 2258.7 m(2)g(-1) and an average pore size of 2.246 nm. Sulfur was then loaded into the activated carbon (AC), and this S/HSAAC (62 wt%) was used as a cathode for Li-S batteries. These batteries delivered an initial discharge capacity of 1233 mAhg(-1) at a current density of 200 mAg(-1). Due to the strong absorption force of the micropores and a high pore volume, the cells retained 929 mAhg(-1) with 80% capacity retention of the initial discharge after 100 cycles. Considering its low cost and ability to be produced at a large-scale, biomass-derived HSAAC is a promising electrode material that may advance high-energy rechargeable lithium-sulfur batteries toward use in practical applications.