Cloud cap-like, hierarchically porous carbon derived from mushroom as an excellent host cathode for high performance lithium-sulfur batteries

Abstract

Carbon host materials play an important role in improving the electrochemical performances of lithium-sulfur batteries. In this work, a novel, cloud cap-like and phosphorus/nitrogen co-containing biomass carbon material derived from mushroom as cathode host materials for lithium sulfur batteries were fabricated by a facile H3PO4 activation method. The porous carbon carbonized at 650°C contains abundant micro/mesopores and possesses the high BET surface area of 788m2g−1 and the main pore size of 1.1–2.5nm, which can boost the adsorption of sulfur and polysulphides by melt-diffusion technology. The sulfur/biomass carbon composite delivers the high initial specific capacity of 1357.8mAhg−1 at 0.1C and high capacity retention of 729mAhg−1 after 100 cycles due to its specific porous structure. The relatively high discharge capacity of 213mAhg−1 is exhibited in the composite even after 72 cycles at higher discharge rates (0.2C, 0.3C, 0.5C, 1C and 2C). All these superior performances well validate the excellent stability and reversibility of the biomass porous carbon as a promising cathode matrix for lithium-sulfur batteries. In addition, the biomass carbon derived from mushroom contains simultaneously phosphorus and nitrogen, which can improve the specific capacity. For the present carbon materials, the special porous structure may encapsulate sulfur particles, inhibit the dissolution of polysulphides in the electrolyte and thus lead to the excellent performances of the materials. Our study shows that the porous biochar arising from mushroom can be easily fabricated and considered as the promising conductive materials for high performance lithium-sulfur batteries.