Enhancing the adsorption and catalytic conversion of polysulfides by nitrogen doped carbon micro-flowers embedded with Mo2C nanoparticles.

Synthesis of hybrid architectures for sulfur host materials has been certificated as an efficient way to enhance the performances of lithium-sulfur (Li–S) batteries owing to the generated synergetic effects from each component. However, it remains challenging to construct hybrid nanostructures with reasonable structure and rational composition to achieve high-performance of Li–S batteries. Here, a coordinated nanostructure constituted of the Mo 2 C nanoparticles embedded in the micro-flowered high content N-doped (11.73 at.%) carbon substrate (Mo 2 C@NC) is synthesized via using protonated g-C 3 N 4 as the template, which is used as the sulfur host for Li–S batteries. Owing to the physical entrapment from the porous carbon substrate with special micro-flower morphology, and the synergistic chemisorption from pyridine N sites and polar Mo 2 C nanoparticles, the as-prepared Mo 2 C@NC can afford a high content of sulfur loading and enables fast/reliable sulfur electrochemistry. Given these, the Mo 2 C@NC based cathode with a high sulfur content of 76% delivers a high initial discharge capacity of 1403.7 mAh g−1 at 0.1 C. Even at a high rate of 2.0 C, it still shows desirable electrochemical performances with an initial capacity of 910.6 mAh g−1 and superb cycling stability with an average capacity decay rate of only 0.001% per cycle over 500 cycles. Moreover, upon a high sulfur loading of 5.5 mg cm −2, the Mo 2 C@NC/S cathode can still maintain decent sulfur related electrochemistry and achieves a high areal capacity of 5.56 mAh cm−2 with excellent stability. It is expected this work provides a new perspective to the rational design of conductive and polar material that suitable for high-efficiency and long-lasting Li–S batteries. [Display omitted] [ABSTRACT FROM AUTHOR]