Synthesis of an Advanced Sulfur Cathode with a Porous Graphitic C/Fe₃C Electrocatalyst and Three-Dimensional Current Collector for Li–S Batteries

Abstract

This work reports on the synthesis of an advanced sulfur cathode incorporating porous graphitic C/Fe 3 C microspheres as an electrocatalyst and carbon fiber paper (CFP) as a three-dimensional (3D) current collector through vacuum filtration. This facile strategy eliminates the need for high-surface-area carbon materials, metal current collectors, and the associated complex procedures. As a 3D current collector, CFP provides efficient pathways for the rapid transfer of electrons and offers additional nucleation sites for the deposition of end redox products. The C/Fe 3 C microspheres are prepared using spray pyrolysis with thermal reduction, which created a range of micro-and mesopores for physically adsorbing polysulfides as well as evenly dispersed Fe 3 C nanoparticles for promoting fast conversion and nucleation. As a result, the optimum sulfur cathode retained approximately 96% of its initial capacity, achieving a specific capacity of around 1171 mAh g −1 after 100 cycles. This cathode also demonstrated superior rate performance, particularly at high current rates of 3.0, 4.0, and 5.0 C, delivering high capacities of ∼700, 600, and 500 mAh g −1 , respectively. This study highlights the potential for achieving high-performance Li−S batteries without confining sulfur in high-surface-area carbon materials and the complex procedures associated with them.