A Novel Sulfur Cathode Architecture for High Capacity and Durable Li-S Battery

Abstract

Li-S battery technology has the potential for low cost and high capacity (up to 1470 mAh/g) battery technology for electric and stationary applications[1]. However, polysulfide creation and their dissolution in electrolytes and lack of conductivity makes it difficult to formulate sulfur cathode for Li-S battery [2-4]. Majority of the efforts to-date involved either coatings or impermeable membranes and electrolyte additives. Herein, we report the use of a mesoporous layer for Sulfur cathodes to suppress polysulfide dissolution and capacity decay in Li-S batteries. The electrode fabricated with the meso-porous coating exhibited high and stable gravimetric discharge capacity of ~ 750 mAh/g over 100 cycles. Sulfur is supported on carbonized polyacrylonitrile (PAN) to improve the electrical conductivity in the electrode. The other part of the electrode is designed in a simple way to withstand the expansion and contraction in order to obtain higher and stable gravimetric capacity with improved cyclability. Cyclic voltammetry and impedance spectroscopy is used to understand various processes during Li alloying and de-alloying reactions within sulfur cathode. Results are compared between electrodes with and without the meso-porous coating. The fabrication procedure for our sulfur cathode is simple and scalable in terms of commercial scale manufacturing. REFERENCES 1. Bruce, P.G., et al., Li-O2 and Li-S batteries with high energy storage. Nat Mater, 2012. 11(1): p. 19-29. 2. Singhal, R., et al., A free-standing carbon nanofiber interlayer for high-performance lithium–sulfur batteries. J. Mater. Chem. A, 2015. 3(8): p. 4530-4538. 3. Ma, X.Z., et al., S–TiO2 composite cathode materials for lithium/sulfur batteries. Journal of Electroanalytical Chemistry, 2015. 736: p. 127-131. 4. Manthiram, A., et al., Rechargeable lithium-sulfur batteries. Chem Rev, 2014. 114(23): p. 11751-87.