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

摘要

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 lowtemperature 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℃and~1550 mAh g−1 at 60℃,thus providing a wider temperature range of applications.This work provides new perspectives on the cathode design for high-rate lithium-sulfur batteries.