Highly Ordered Mesoporous Sulfurized Polyacrylonitrile Cathode Material for High-Rate Lithium Sulfur Batteries

A highly ordered mesoporous sulfurized polyacrylonitrile (MSPAN) composite has been synthesized via in situ polymerization of polyacrylonitrile (PAN) in an SBA-15 template followed by sulfurization. The synthesized composite possessed high sulfur utilization, high Coulombic efficiency, and excellent cycling stability as a cathode active material for high-rate lithium sulfur (Li-S) batteries. A highly ordered mesoporous structure was observed in the MSPAN composite from transmission electron microscopy. Excellent electrochemical and stable cycling performances of the MSPAN composite were obtained, especially at high C rates. The capacity retention of the MSPAN cell was 755 mAh g(-1) after 200 cycles at 1 C and 610 mAh g(-1) after 900 cycles at 2 C. Even at a higher rate of 5 C, the composite showed reasonable capacity retention. The superior performance of the MSPAN composite was attributed to its highly porous structure, which could effectively improve the wettability, accessibility, and absorption of electrolyte, facilitating rapid ion transfer in Li-S batteries. The electrochemical results demonstrate that the highly ordered mesoporous MSPAN composite is a promising cathode active material for advanced Li-S batteries.