Facile synthesis of sulfurized polyacrylonitrile composite as cathode for high-rate lithium-sulfur batteries

Sulfurized polyacrylonitrile (SPAN) as a promising cathode material for lithium sulfur (Li-S) batteries has drawn increasing attention for its improved electrochemical performance in carbonate-based electrolyte. However, the relatively poor electronic and ionic conductivities of SPAN limit its high-rate and low-temperature performances. In this work, a novel one-dimensional nanofiber SPAN (SFPAN) composite is developed as the cathode material for Li-S batteries. Benefitting from its one-dimensional nanostructure, the SFPAN composite cathode provides fast channels for the migration of ions and electronics, thus effectively improving its electrochemical performance at high rates and low temperature. As a result, the SFPAN maintains a high reversible specific capacity ~ 1200 mAh g−1 after 400 cycles at 0.3 A g−1 and can deliver a high capacity of ~ 850 mAh g−1 even at a high current density of 12.5 A g−1. What is more, the SFPAN can achieve a capacity of ~ 800 mAh g−1 at 0 °C and ~ 1550 mAh g−1 at 60 °C, thus providing a wider temperature range of applications. This work provides new perspectives on the cathode design for high-rate lithium-sulfur batteries.