Nitrogen-doped carbonaceous scaffold anchored with cobalt nanoparticles as sulfur host for efficient adsorption and catalytic conversion of polysulfides in lithium-sulfur batteries

• Published in: Electrochimica acta 2021-07, Vol.383, p.138371, Article 138371
• Main Authors: Fan, Bin, Zhao, Dengke, Xu, Wei, Wu, Qikai, Zhou, Wei, Lei, Wen, Liang, Xinghua, Li, Ligui
• Format: Article
• Language: English
• Subjects: Adsorption; Attenuation; Carbon nanotubes; Carbonaceous materials; Catalytic converters; Conversion; Electron transfer; High sulfur loading; Lithium; Lithium polysulfides; Lithium sulfur batteries; Nanoparticles; Nitrogen doping; Nucleation; Polysulfides; Scaffolds; Substrates
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2021.138371

•The conversion of sulfur is accelerated effectively by as-constructed Co-NCNT scaffold.•The rationally designed Co-NCNT guarantees efficient electrons/ions transfer pathways.•The S@Co-NCNT cathode with high sulfur loading shows excellent performances. The effective inhibition of lithium polysulfides (LiPSs) and promotion of their conversion in the redox processes is indispensable to achieve the long cycle stability and excellent rate performance of lithium-sulfur (Li-S) batteries. Especially, the generally slow electrocatalytic sulfur redox kinetics and large interfacial Li2S nucleation energy barriers have hindered the widespread application of Li-S batteries. Herein, a robust three-dimensional sulfur carrier (denoted as Co-NCNT) is well-constructed using the potassium citrate derived porous carbon sheets as substrate and the catalytic growth nitrogen-doped porous carbon nanotubes as vertical scaffolds. Such a rationally designed structure guarantees efficient electron transfer pathways and ions diffusion channels. More importantly, it is conducive to the adsorption/catalytic conversion of intermediate lithium polysulfides and the nucleation of Li2S. Due to these merits, the S@Co-NCNT cathode achieves an initial discharge capacity up to 1072.7 mAh g−1 at 1.0 C, and it can retain a high capacity of 482.9 mAh g−1 with a capacity attenuation rate of only 0.045% per cycle after 1000 cycles. Upon a high sulfur loading of 5.87 mg cm−2, the S@Co-NCNT electrode can still reach an initial capacity of 739.5 mAh g−1 at 0.3 C. Particular emphasis is that our work broadens the way to prepare well-designed carbonaceous materials sulfur host for long-life Li-S batteries. The cobalt-catalyzed growth of nitrogen-doped carbon nanotubes on the porous carbon nanosheets is well-designed as the robust scaffold for efficient loading of sulfur. It is manifested that this structure is conducive to the adsorption/catalytic conversion of intermediate lithium polysulfides and the nucleation of Li2S, holding great promise in developing practically viable lithium sulfur batteries [Display omitted] .