Synthesis of sulfur-co-polymer/porous long carbon nanotubes composite cathode by chemical and physical binding for high performance lithium-sulfur batteries

Abstract

The composite cathode of sulfur-rich polymer and long cylindrical porous multiwalled carbon nanotubes (LCNT) is reported for high performance lithium-sulfur (Li–S) batteries through combining both chemical and physical binding strategies of sulfur, respectively. This technique efficiently exploits the synergistic effect of ability of stabilizing the polymeric sulfur. The role of uniform distribution of highly conductive LCNT network is optimized as a cathode host material by solution route. Annealed sulfur-co-polymer (S-co-poly) composites are homogeneously well attached via physisorption with LCNT submicron channel. The composite shows a high discharge capacity of 1040 mAh g−1 in the 1st cycle of galvanostatic charge-discharge at 0.5C. Whereas, the cell maintains a reversible capacity of 610 mAh g−1 after 200 cycles, showing good capacity rate. Therefore, solvent assisted both synthesis and further proper mixing enables high active material utilization whereas porous submicron channel of CNT network, which provides conducting pathway, adsorbs sulfur copolymer homogeneously for better electrochemical performance.