Graphene sheet-encased silica/sulfur composite cathode for improved cyclability of lithium-sulfur batteries

• Published in: Journal of solid state electrochemistry 2021-03, Vol.25 (3), p.939-948
• Main Authors: Rajkumar, P., Diwakar, K., Subadevi, R., Gnanamuthu, R. M., Wang, Fu-Ming, Liu, Wei-Ren, Sivakumar, M.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Cathodes; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Composite materials; Condensed Matter Physics; Decay rate; Electrochemical analysis; Electrochemistry; Electron transport; Energy Storage; Graphene; Lithium sulfur batteries; Original Paper; Physical Chemistry; Polysulfides; Silicon dioxide; Sulfur
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-020-04747-3

The “shuttle effect” of polysulfides is a serious issue, resulting in a decrease in the life-cycle of lithium-sulfur (Li-S) batteries. To inhibit the shuttle effect, a combination of graphene oxide and silica has been adopted in this work. Here, two different ratios of sulfur/silicon dioxide/partially reduced graphene oxide (S/SiO 2 /prGO - 70:20:10 and 70:10:20) composite materials were prepared via a melt diffusion method and were used as a cathode for a Li-S battery. The wrinkled sheets of partially reduced graphene oxide not only provide a conductive network for electron transport, but also ease the volume changes of active material during cycling. The 20 wt% of prGO present in the S/SiO 2 /prGO cathode delivers initial discharge capacity of 783 mAh g −1 at 0.2 C and remains at 491 mAh g −1 over 300 cycles, with low capacity decay rate of 0.12% per cycle. The better electrochemical performance indicates that the electrode containing 20 wt% of prGO with silica effectively suppresses the “shuttle effect” of polysulfide dissolution. Graphical abstract