Carbon Hotels with Nanosulfur Guests: Promising High Capacity Cathode Architecture with Hybrid Electrolyte for Lithium-Sulfur Battery

Lithium-sulfur battery is highly appealing primarily due to its high theoretical specific energy of 2567 Whkg^-1 and specific capacity of 1672 mAhg^-1, both values an order of magnitude higher than those of commercialized Li-ion systems.^1-2 Despite the wealth of literature demonstrating remarkable carbon-sulfur cathode architectures for Li-S systems, their industrial adoption is limited by performance issues such as low columbic efficiency, poor cycle life, and impractical syntheses. It is imperative that continuing studies on Li-S systems recognize the importance of the underlying fundamental chemistry for progress to be seen. The focus of this work is to develop, characterize, and optimize both Li-S materials and synthesis processes in the pursuit of a practical Li-S rechargeable battery.

Through this work, we understand the shuttle mechanisms and its effect on stable cycling performance and high columbic efficiency in Li-S systems. Initially, we have fabricated carbon hotels using starch based precursor with solid state synthesis approach. These premade hollow carbon particles are filled in situ with sulfur nanoparticles, sonochemically.  The electrolyte used is DOL:D2:LiTFSI. The newly developed C-S  composite cathode demonstrates high columbic efficiency (minimum 97%) and ~900 mAh/g reversible capacity during long cycling.

References

1. Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J.-M. Nature Materials 2012, 11.

2. W. Weng, V. G. Pol, K. Amine, Adv. Mater., 2013, 25, 1608–1615