Design and Synthesis of Polyaniline Encapsulated Sulfur Impregnated Porous Carbon Composites as Cathode Material for Advanced Lithium Sulphur Batteries

Lithium-ion batteries (LiIBs) are increasingly challenged by the growing performance requirements of modern consumer electronics, creating a strong need for alternative rechargeable energy-storage systems with higher theoretical energy density and potentially lower material cost. Lithium–sulfur batteries (LiSBs) are among the most promising beyond-Li-ion technologies; however, practical development requires cathode materials capable of improving sulfur utilization and maintaining stable cycling performance. In this work, a sulfurized polyaniline-coated phosphorus-doped porous carbon (PANI@S/P-PC) composite was designed and synthesized as an advanced cathode material for Li–S batteries. The composite architecture integrates sulfur, a conductive polymer coating, and a heteroatom-doped porous carbon framework within a single cathode material. The prepared composites were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), surface-area analysis (SAA), and Fourier-transform infrared spectroscopy (FTIR) to evaluate their structural, morphological, compositional, and surface characteristics. Electrochemical performance was investigated in terms of specific capacity, capacity retention, cyclic performance, and rate performance. The synthesized PANI@S/P-PC composite exhibited suitable surface morphology and a high specific surface area of 278 m² g⁻¹. When evaluated as a cathode material in lithium–sulfur batteries, the composite delivered an initial specific capacity of 876 mAh g⁻¹ at a current rate of 0.2 C. After 100 charge–discharge cycles, the electrode retained a capacity of 552.2 mAh g⁻¹, corresponding to a low capacity-fading rate of approximately 0.4% per cycle. These results demonstrate the potential of conductive-polymer-encapsulated, heteroatom-doped porous-carbon composites as functional cathode architectures for advanced lithium–sulfur energy-storage systems.