Flower-like nitrogen-oxygen-doped carbon encapsulating sulfur composite synthesized via in-situ oxidation approach

Abstract Lithium sulfur battery, with higher gravimetric energy, is regarded as one of the promising next-generation energy storage devices. However, rapid capacity fading and poor rate capability under higher loading hinder its practical applications. Despite the encouraging progress achieved, the cost-effective solutions are still need to be sought for. Herein, a flower-like nitrogen-oxygen-doped carbon coated sulfur (F-S@NOC) composite was synthesized from a low-cost sulfur-containing organic ferro-compound, through a facile calcination and an in-situ oxidation process. The unique flower configuration is constructed by two-dimensional flake petal unit that not only expose more polar nitrogen/oxygen-containing functional groups for anchoring the dissolved intermediates of lithium polysulfides (LiPSs), but also facilitate improved electrochemical reaction kinetics since fast electron/Li + transfer. Therefore, F-S@NOC demonstrates excellent electrochemical performances that a decay rate of 0.05% per cycle at 1C, and a high initial areal capacity of 4.49 mAh cm −2 at 0.2C, are obtained respectively under the sulfur loading of 3 and 4.6 mg cm −2 .