Mango stone-derived activated carbon with high sulfur loading as a cathode material for lithium-sulfur batteries

A set of mango stone (MS)-derived activated carbons with tunable pore structure parameters have been synthesized via a KOH activation procedure. The maximum specific surface area of 3334 m(2) g(-1) and pore volume of 2.17 cm(3) g(-1) are obtained for the material which is pre-carbonized at 500 degrees C and treated with a KOH/char mass ratio of 4 (a-MSs-500-4). Given the large pore volume of the resultant a-MSs-500-4 activated carbon, a high sulfur loading of up to 71 wt% can be achieved (a-MSs-500-4/71). When applied in a lithium-sulfur battery, the a-MSs-500-4/71 composite cathode exhibits 64% capacity retention over 500 cycles at 800 mA g(-1) and 45% capacity retention over 1000 cycles at 1600 mA g(-1), indicating excellent long-term cycling performance. Moreover, after 1 wt% LiNO3 is introduced as the electrolyte additive, the average coulombic efficiency of the electrode is as high as approximately 99%.