Reduced graphene oxide coated porous carbon–sulfur nanofiber as a flexible paper electrode for lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries have attracted great attention owing to their excellent electrochemical properties, such as the high discharge voltage of 2.3 V, specific capacity of 1675 mA h g⁻¹ and energy density of 2600 Wh kg⁻¹. The widely used slurry made electrodes of Li–S batteries are plagued by the serious shuttle effect and insulating nature of sulfur. Herein, a reduced graphene oxide coated porous carbon nanofiber flexible paper (rGO@S-PCNP) was fabricated and directly used as an additive-free cathode for Li–S batteries. The results show that the rGO@S-PCNP is certified to be effective at relieving the shuttle effect and improving the conductivity, thus achieving high electrochemical performance. The rGO@S-PCNP composite with a sulfur content of 58.4 wt% delivers a high discharge capacity of 623.7 mA h g⁻¹ after 200 cycles at 0.1 C (1 C = 1675 mA g⁻¹) with the average Coulombic efficiency of 97.1%. The excellent cyclability and high Coulombic efficiency indicate that the as-prepared rGO@S-PCNP composite paper can be a promising cathode for lithium–sulfur batteries, and is envisioned to have great potential in high energy density flexible power devices. This facile strategy brings great significance for large-scale industrial fabrication of flexible lithium–sulfur batteries.