Tailoring interactions of carbon and sulfur in Li-S battery cathodes: significant effects of carbon-heteroatom bonds

In this study, effects of carbon-heteroatom bonds on sulfur cathodes were investigated. A series of carbon black substrates were prepared using various treatments to introduce nitrogen or oxygen surface species. Our results indicated that nitrogen-doped carbon black significantly improved the electrochemical performance of sulfur cathode materials. Synchrotron-based XPS revealed that the defect sites of nitrogen-doped carbon are favorable for the discharge product deposition, leading to a high utilization and reversibility of sulfur cathodes. Our studies also found that the introduction of oxygen functional groups results in deteriorated performance of Li-sulfur batteries due to the reduced conductivity and unwanted side reactions occurring between sulfur and surface oxygen species.