V2CTX catalyzes polysulfide conversion to enhance the redox kinetics of Li–S batteries

Abstract

Lithium–sulfur (Li–S) batteries have the potential to become the future energy storage system, yet they are plagued by sluggish redox kinetics. Therefore, enhancing the redox kinetics of polysulfides is key for the development of high-energy density and long-life Li–S batteries. Herein, a Ketjen Black (KB)/V₂CT_X modified separator (KB/V₂CT_X-PP) based on the catalytic effect in continuous solid-to-liquid-to-solid reactions is proposed to accelerate the conversion of sulfur species during the charge/discharge process in which the V₂CT_X can enhance the redox kinetics and inhibit polysulfide shuttling. The cells assembled with KB/V₂CT_X-PP achieve a gratifying first discharge capacity of 1236.1 mA h g⁻¹ at 0.2C and the average capacity decay per cycle reaches 0.049% within 1000 cycles at 1C. The work provides an efficient idea to accelerate redox conversion and suppress shuttle effects by designing a multifunctional catalytic separator.