Centrifugally spun porous carbon microfibers as interlayer for Li–S batteries

Lithium–sulfur (Li–S) batteries have attracted great interest owing to their high energy density. However, shuttling of polysulfides deteriorates the electrochemical performance of Li–S batteries and prevents their practical applications. Placing a conductive and porous interlayer structure between the cathode and the separator limits the shuttling effect and improves the cycling performance. Here, porous carbon microfibers are fabricated via a fast, safe and cost-effective centrifugal spinning approach and the resultant centrifugally spun porous carbon microfibers (CS-PCMFs) are evaluated for use as an interlayer in Li–S batteries. The highly porous fibrous structure is observed from SEM and TEM images, and a high initial discharge capacity of 1485 mAh g⁻¹ is achieved. A high reversible capacity of 615 mAh g⁻¹ is reached after 200 cycles at 0.2 C. In addition, the cell with CS-PCMF interlayer has low cell resistance of 25 O, whereas that of Li–S cell without interlayer is 55 O. Owing to the low cell resistance, the cell with CS-PCMF interlayer delivers the reversible capacity of around 600 mAh g⁻¹ at 1 C, while the cell without interlayer exhibits a lower capacity of 250 mAh g⁻¹. Therefore, this work provides a new approach for designing highly porous carbon microfiber interlayer for Li–S batteries with exceptional electrochemical performance.