Tunable pore structure for confining polysulfides in high performance Li-S battery with coal precursor

• Published in: Applied surface science Vol. 458; pp. 714 - 721
• Main Authors: Kang, Danmiao, Tang, Kun, Lemmon, John P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2018
• Subjects: Li-S battery; Polysulfides confinement; Porous carbon; Shuttle effect; Small mesopores; Polysulfides confinement; Porous carbon; Li-S battery; Small mesopores; Shuttle effect
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.07.139

•Applied coal as the precursors of Li-S cathode materials for the 1st time.•The pore structure of carbon in Li-S cathode is tunable when prepared by coals with different coalification degrees.•Small mesopores is found most effective to support more sulfur and confine polysulfides.•The Li-S cathode show high cycling stability, with over 84% capacity retention after 100 cycles at 0.5 C. The lithium-sulfur (Li-S) battery is a promising technology for next generation energy storage systems due to low cost materials and high theoretical energy capacity. However, the well-known ‘shuttle effect’ of polysulfides, that has significant impact on battery performance, has impeded the commercialization of Li-S batteries with high volumetric energy density and cycle life necessary for economic viability. Herein, we provide a facile method for the fabrication of hierarchical porous carbon with optimal pore structure to support sulfur in the cathode. The specific surface area of the coal-derived hierarchical porous carbon can be as high as 3343 m2/g, with a high distribution of pores between 2 and 5 nm, which is both beneficial to confining the polysulfides and increased sulfur loading (as high as 76 wt%). With most of sulfur confined in small mesopores, the carbon/sulfur composites show a high specific capacity of 1390 mAh/g at 0.05 C with ∼85% capacity retention after 100 cycles at 0.5 C.