Core-shell S@C₃N₄ nano-spheres as advanced adsorbent material for excellent lithium storage

The application of the lithium-sulfur batteries is limited by their poor cycle stability. As for the reason of the poor cycle stability, it is caused by the poor electronic conductivity, dissolution of the polysulfide and the volume change of the sulfur during the electrochemical cycles. To improve the cycle performance of the lithium-sulfur batteries, many strategies have been proposed and applied for the lithium-sulfur batteries, including designing suitable host materials, protecting lithium anode and modifying the electrolyte. In this paper, core–shell C3N4 spheres are prepared and used as the host materials for the sulfur. The as-prepared S@C3N4 composites could deal with three shortcomings at the same time. As a result, the capacity of S@C3N4 composites stabilizes at 726 mAh g−1 with the capacity retention of 92% after 500 cycles at 0.5 C.