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

Abstract

Utilizing the oxygen-doping carbon, rational tailoring of morphology and pores were designed for Li-S battery, resulting in the negative charge surface carbon matrix with fascinating pore structure. Carbon with mesopore and big zeta potential was constructed to improve lithium-storage capabilities the restrain of soluble polysulfide and the kinetic during solid-state. 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 Li 2 S x (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 S 8 and Li 2 S, 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.