Sulfur-Immobilized Nitrogen and Oxygen Co-Doped Hierarchically Porous Biomass Carbon for Lithium-Sulfur Batteries: Influence of Sulfur Content and Distribution on Its Performance

Abstract Hierarchically porous carbon with inherently doped heteroatoms and the quantity of active material (sulfur) confined within this carbon matrix play a major role for the high performance of Li−S batteries. Herein, we discuss the influence of sulfur content and distribution onto the N and O co‐doped hierarchically porous biomass carbon matrix (PC) to achieve high specific capacitance and cycling stability. Sulfur encapsulated PC was prepared from an eco‐friendly source with a high surface area of 2065 m 2 g −1 and a pore volume of 1.5 cm 3 g −1 . PC with 54, 68 & 73% of sulfur content (PCSCs) have been investigated as cathode materials for Li−S battery. PC with 54% sulfur displayed better performance with an initial discharge capacity of 1606 mA h g −1 and a cycling stability of 1269 mA h g −1 at 0.1C rate after 100 cycles due to better dispersion of sulfur in the porous architecture. The higher cycling stability of PCSC (54%) is due to the N and O co‐doped hierarchical porous carbon layers, enhancing the sulfur utilization ratio and mitigating the polysulfide shuttle during the cycling process.