Insights into the aspect ratio effects of ordered mesoporous carbon on the electrochemical performance of sulfur cathode in lithium-sulfur batteries

• Published in: Journal of colloid and interface science 2024-07, Vol.665, p.286-298
• Main Authors: Xiang, Yinyu, Lu, Liqiang, Zhang, Yongsheng, Ersek, Gabor, Portale, Giuseppe, Li, Wenjian, Zhang, Wei, Kottapalli, Ajay Giri Prakash, Pei, Yutao
• Format: Article
• Language: English
• Subjects: batteries; carbon; cathodes; electrochemistry; electrolytes; Lithium-sulfur battery; Ordered mesoporous carbon; Particle aspect ratio; Polysulfide; porous media; prototypes; silica; small-angle X-ray scattering; species; sulfur; Sulfur evolution
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2024.03.128

Aspect ratio of OMCs is tuned, and correlations between aspect ratio of OMCs and battery performance of S@OMCs are systematically studied. Evolution of sulfur species in OMCs is revealed by SAXS, providing guidelines for optimizing sulfur cathodes. [Display omitted] Tailoring porous host materials, as an effective strategy for storing sulfur and restraining the shuttling of soluble polysulfides in electrolyte, is crucial in the design of high-performance lithium-sulfur (Li-S) batteries. However, for the widely studied conductive hosts such as mesoporous carbon, how the aspect ratio affects the confining ability to polysulfides, ion diffusion as well as the performances of Li-S batteries has been rarely studied. Herein, ordered mesoporous carbon (OMC) is chosen as a proof-of-concept prototype of sulfur host, and its aspect ratio is tuned from over ∼ 2 down to below ∼ 1.2 by using ordered mesoporous silica hard templates with variable length/width scales. The correlation between the aspect ratio of OMCs and the electrochemical performances of the corresponding sulfur-carbon cathodes are systematically studied with combined electrochemical measurements and microscopic characterizations. Moreover, the evolution of sulfur species in OMCs at different discharge states is scrutinized by small-angle X-ray scattering. This study gives insight into the aspect ratio effects of mesoporous host on battery performances of sulfur cathodes, providing guidelines for designing porous host materials for high-energy sulfur cathodes.