Nano-carbon-fiber-penetrated sulfur crystals as potential cathode active material for high-performance lithium–sulfur batteries

• Published in: Carbon (New York) Vol. 159; pp. 401 - 411
• Main Authors: Shih, Hsuan-Ju, Chang, Jin-Yu, Cho, Chuan-Sheng, Li, Chia-Chen
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 15-04-2020; Elsevier BV
• Subjects: Batteries; Carbon fibers; Cathodes; Composite materials; Conductivity; Crystals; Discharge; Electrode polarization; Lithium sulfur batteries; Sulfur; Tape casting
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2019.12.055

A novel composite consisting of vapor-grown carbon fibers penetrating sulfur crystals is developed. Using this new composite as the cathode active material greatly improves the ionic and electronic conductivity of fabricated lithium–sulfur batteries and helps to suppress the polarization of S intermediates during the charging and discharging processes. Importantly, the special structure of the composite also offers the potential of freely achieving high areal mass loading and capacity via the cost-efficient tape-casting method. The constructed battery exhibits a highly stable capacity of 920 mA h g−1 at 0.1C with good retention of 90% after 200 charge–discharge cycles and a good coulombic efficiency of 100%. Furthermore, good areal capacities of 3.4–4.4 mAh cm−2 with retention of 93–97% through cycles under 0.2–0.5C are achieved. These good performances are attributed to the greatly improved conductivity of the sulfur electrode, better utilization of sulfur, and the lower dissolution and shuttle effect of the polysulfides in the cell.
[Display omitted]