Highly Packed Monodisperse Porous Carbon Microspheres for Energy Storage in Supercapacitors and Li−S Batteries

Abstract Porous carbon microspheres and S/microspherical carbon composites with a highly packed hexagonal arrangement have been synthesized by chemical activation of precarbonized resorcinol‐formaldehyde spheres. Sodium thiosulphate is used as a harmless activating agent, S dopant and sulfur precursor. The porous microspheres exhibit large surface areas (2060–2340 m 2 g −1 ) and adequate micro‐mesoporosity. They also have a notable amount of sulfur heteroatoms (5–7 %) and high electronic conductivity (2.3–3.1 S cm −1 ). The compact organization and suitable porosity of the microspheres allow competitive values of volumetric capacitance to be achieved when used in supercapacitors operating in aqueous and organic electrolytes (130 and 64 F cm −3 , respectively), while maintaining good rate capability. In addition, the sulfur/spherical carbon composites with a sulfur content above 80 % are tested as cathode material in lithium‐sulfur batteries, demonstrating high sulfur utilization, large values of volumetric capacity (768 mAh cm −3 ) and stable long‐term cyclability (0.086 % capacity loss per cycle).