Influence of organizational features of heteroatom-doped carbon on sulfur cathode performance in lithium-sulfur batteries

Lithium–sulfur batteries (LSBs) have attracted significant attention due to its high theoretical capacity of sulfur (1675 mA h g−1). Mass production and distribution of LSB is significantly hindered by various real-world challenges. The primary issues include the polysulfide transport and the low electric conductivity of sulfur. This study investigates electrochemical properties of 4, 4’-diamino-diphenyl sulfone derived carbon sulfur (DDSCS) composites prepared with varying pyrolysis time. Two composites, DDSC-1S and DDSC-2S, each with a sulfur loading of 74 %, were analyzed as cathode materials for LSBs. Among them, DDSC-2S demonstrated superior electrochemical performance compared to DDSC-1S, delivering initial discharge capacity of 995 mA h g−1 and retaining 79 % of its capacity at a 0.1 C rate. The improved capacity retention is ascribed to the collective effect of the high surface area, and large pore volume along with heteroatoms such as nitrogen and oxygen, which efficiently limit the movement of polysulfides.