High sulfur loading in activated bamboo-derived porous carbon as a superior cathode for rechargeable Li–S batteries

A novel type of porous carbon material for Li–S batteries was obtained by simple pyrolysis of natural bamboo waste at 850 °C. The activated bamboo-derived carbon (A_BC) contains abundant micropores and mesopores, possessing a large surface area of 1565.4 m2 g−1 and total pore volume of 0.95 cm3 g−1, which are larger than vast majority of biomass materials. All these advantages contribute to improving sulfur loading in the A_BC matrix materials, and a high sulfur content of 86 wt% in the A_BC/S composite can be achieved. As the cathode for Li–S batteries, it displayed superior electrochemical properties, with an initial discharge capacity of 1160 mA h g−1 at 0.1 C (1 C = 1675 mA g−1) and 1050 mA h g−1 remained after ten cycles. Further cycled at 0.2 C for one hundred cycles, reversible capacity of 930 and 710 mA h g−1 was reserved for the first and the 100th cycle, respectively. Further increasing to 0.5 C and 1 C, it still showed capacities of 695 and 580 mA h g−1 with coulombic efficiency over 95%, suggesting this porous A_BC could be a superior carbon matrix for high sulfur loading as the cathode of rechargeable Li–S batteries.