Facile construction of porous carbon fibers from coal pitch for Li-S batteries

Coal pitch, an important by-product in the coal coking industry with a high output, is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials. Herein, N/O co-doped carbon fiber (CF_CP), fabricated by electrospinning using pre-oxidized coal pitch as the precursor, was employed as the sulfur host for Li-S batteries. The presence of more pyrrolic N and graphic N in CF_CP than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfide and the battery’s life. Sulphur-CF_CP cathode (S@CF_CP) exhibited excellent specific capacity and cyclability, with a specific capacity of 701.1 mAh/g and a low capacity decay rate of 0.088% per cycle over 200 cycles at 2.0 C, respectively. The high ion diffusion rate, low charge transfer resistance, and effective conversion of lithium polysulfides enable the high electrochemical performance of S@CF_CP.