Engineering the morphology/porosity of oxygen-doped carbon for sulfur host as lithium-sulfur batteries

Despite the intriguing merits of lithium-sulfur (Li-S) systems, they still suffer from the notorious ''shuttling-effect of polysulfides. Herein, carbon materials with rational tailoring of morphology and pores were designed for strong loading/adsorption with the controlling of energy-storage ability. Through rational tailoring, it is strongly verified that such engineering of evolutions result in variational of sulfur immobilization in the obtained carbon. As expected, the targeted sample delivers a stable capacity of 925 mAh g(-1) after 100 loops. Supporting by the ''cutting-off manners, it is disclosed that mesopores in carbon possess more fascinated traits than micro/macropores in improving the utilization of sulfur and restraining Li2Sx (4 <= x <= 8). Moreover, the long-chain polysulfide could be further consolidated by auto-doping oxygen groups. Supported by in-depth kinetic analysis, it is confirmed that the kinetics of ion/e(-) transfer during charging and discharging could be accelerated by mesopores, especially in stages of the formation of solid S8 and Li2S, further improving the capacity of ion-storage in Li-S battery. Given this, the elaborate study provide significant insights into the effect of pore structure on kinetic performance about Li-storage behaviors in Li-S battery, and give guidance for improving sulfur immobilization. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press.

Automated summary

This study designed carbon materials with rational morphology and pore structures to enhance the loading and adsorption capacity of sulfur, thereby improving the energy storage performance of lithium-sulfur batteries. Through rational design, variations in sulfur immobilization were successfully achieved, leading to increased cycling stability. The results show that mesopores in carbon exhibit more fascinating traits in improving sulfur utilization and suppressing Li2Sx formation, ultimately enhancing ion storage capacity in Li-S batteries.