From Silica Sphere to Hollow Carbon Nitride‐Based Sphere: Rational Design of Sulfur Host with Both Chemisorption and Physical Confinement

Abstract

To suppress the shuttle effect and improve the sulfur utilization in lithium–sulfur battery, a novel hollow carbon nitride‐based spheres material (HCNx) has been synthesized via polymerization of ethylenediamine and carbon tetrachloride on silica spheres and used as a sulfur host. The rational designed structure of HCNx retards diffusion of lithium polysulfides by both chemisorption and physical confinement. The enhanced conductivity of HCNx improves the utilization of the sulfur. As a result, the S/HCNx exhibits a discharge capacity of 579 mA h g−1 after 500 cycles with a fade rate of 0.076% per cycle at 0.5 C. Even at 2 C, the S/HCNx cathode still exhibits a reversible discharge capacity of 658 mA h g−1.