Giant-miscanthus-derived activated carbon and its application to lithium sulfur batteries

Abstract

Giant miscanthus (GM) is an Asian grass that can produce biomass in high yields per land area. It can be used as a cathode material in lithium sulfur (Li/S) batteries. Giant-miscanthus-derived activated carbon (GMAC) is prepared via carbonization of GM followed by KOH activation. It is prepared with a large amount of KOH, and thus contained more defects but had a highly porous structure and graphitic cluster lattice. GMAC has a large specific surface area of 3327 m(2)/g and a large total pore volume of 1.86 cm(3)/g. The pore volume served as a storage space for the retention of polysulfides, thereby inhibiting the shuttle effect. When a GMAC-sulfur composite cathode is tested in a Li/S battery, an initial discharge capacity of 1148 mAh/g can be attained at 0.1 C. In a cyclic charge-discharge experiment at 1 C, discharge capacities of 529 mAh/g and 248 mAh/g are observed in the first and 200th cycles, respectively.