Disordered mesoporous polyacenes/sulfur nanocomposites: Superior cathode materials for lithium-sulfur batteries

Abstract In this work, disordered mesoporous polyacenes/sulfur (DM-PAs/S) composites with the S content of 50–80 wt % were prepared via a simple melt-diffusion strategy. In order to obtain such DM-PAs/S composites, the non-sulfur-containing disordered mesoporous polyacenes (DM-PAs) precursor, which had a high BET surface area of 1136.0 m 2 /g, a pore volume of 1.37 cm 3 /g and unique bimodal mesopores (2.98/7.39 nm), was firstly prepared by using phenol-formaldehyde (PF) resin as raw material as well as both polyethylene glycol (PEG) and ZnCl 2 as activation agents. Electrochemical tests demonstrated that, the as-prepared DM-PAs/S could be served as superior cathode materials for lithium-sulfur batteries. It was disclosed that the DM-PAs/S with the S content of about 67 wt % (S-DM-PAs/S-67) presented the best electrochemical properties when the specific capacity is calculated based on the total mass of DM-PAs/S composite containing active sulfur and inactive DM-PAs. At a charge/discharge rate of 1 C, the S-DM-PAs/S-67 electrode exhibits a good long-term cycling stability with a high reversible capacity of about 513.57 mAh/g Sulfur after 500 cycles. The advanced electrochemical performances should be attributed to the uniform distribution of sulfur in the DM-PAs matrix, high electronic conductivity of DM-PAs, and the effective hinder of dissolvable polysulfides by the pores in the DM-PAs.