Nitrogen/Oxygen Dual-Doped Carbon Nanofibers as an Electrocatalytic Interlayer for a High Sulfur Content Lithium–Sulfur Battery

A self-standing nitrogen/oxygen dual-doped carbon nanofiber matrix is prepared on the basis of polymer chain design and electrospinning followed by a one-step carbonization. The interlayer can substantially suppress the shuttle effect and improve the charge–discharge performance of the lithium–sulfur battery because of the catalytic effect and strong adsorption effect between interlayer and lithium polysulfides. With a sulfur areal loading of 4.54 mg cm–2 and a sulfur mass content of 80% at the whole electrode level, the discharge specific capacity of the initial cycle is 947 mA h g–1. It also contains more than 908 and 800 mA h g–1 after 100 and 200 cycles at 0.1 C with such an interlayer. It is found that the capacity contribution from octasulfur to dilithium tetrasulfide is improved 35% and the utilization ratio of dilithium tetrasulfide to lithium sulfide improved 76% with an interlayer, which is the main reason for the improvement of the capacity. We believe that the cell configuration presented here coupled with further improvements of the sulfur electrode could help to alleviate some of the persistent problems in lithium–sulfur cells.