Glucose-Derived Micro–Mesoporous Carbon Spheres for High-Performance Lithium–Sulfur Batteries

Glucose-derived micro–mesoporous carbon spheres (GMCS) are prepared using glucose as the carbon source and ZnCl2 as the chemical activator through hydrothermal, impregnation treatment and high-temperature calcination. The GMCS have a large specific surface area (SBET = 2128 m2 g–1) such that sulfur can effectively disperse on the surface and inside the micro–mesoporous structure of GMCS; such a micro–mesoporous structure can also inhibit the shuttle effect by adsorbing the polysulfides, thereby enhancing the electrochemical capabilities of lithium–sulfur batteries. As the cathode materials of lithium–sulfur batteries, the S@GMCS composites have good electrochemical performance. The initial discharge capacity of the S@GMCS composites is 1396 mA h g–1 at 0.1 C. When the batteries are cycled for 100 cycles, their discharge capacity remains 1014 mA h g–1, and the coulomb efficiency is close to 100%, which indicates excellent cyclic stability. This study demonstrated that the S@GMCS composites are lithium–sulfur batteries' ideal cathode materials, owing to their unique micro–mesoporous carbon sphere structure and remarkable electrochemical properties.