Confining Sulfur in N-Doped Porous Carbon Microspheres Derived from Microalgaes for Advanced Lithium-Sulfur Batteries

Lithium–sulfur (Li–S) battery is one of the most attractive candidates for the next-generation energy storage system. However, the intrinsic insulating nature of sulfur and the notorious polysulfide shuttle are the major obstacles, which hinder the commercial application of Li–S battery. Confining sulfur into conductive porous carbon matrices with designed polarized surfaces is regarded as a promising and effective strategy to overcome above issues. Herein, we propose to use microalgaes (Schizochytrium sp.) as low-cost, renewable carbon/nitrogen precursors and biological templates to synthesize N-doped porous carbon microspheres (NPCMs). These rational designed NPCMs can not only render the sulfur-loaded NPCMs (NPCSMs) composites with high electronic conductivity and sulfur content, but also greatly suppress the diffusion of polysulfides by strongly physical and chemical adsorptions. As a result, NPCSMs cathode demonstrates a superior reversible capacity (1030.7 mA h g–1) and remarkable capacity retention...