Preparation and performance evaluation of V2O5/Ketjen black composite as a cathode material for lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries have garnered significant research interest owing to their exceptional theoretical energy density, coupled with the cost-effectiveness and environmental sustainability inherent in sulfur-based cathode materials. Nevertheless, the practical implementation of these systems remains impeded by challenges, such as the shuttle effect of soluble lithium polysulfide intermediates during cycling, which contributes to rapid capacity degradation and suboptimal electrochemical performance in current Li–S configurations. Herein, a sulfur-containing composite, S@V 2 O 5 /KB, was synthesized using a straightforward high-temperature melt synthesis method. The V 2 O 5 /KB composite was obtained by mixing vanadium pentoxide (V 2 O 5 ) and Ketjen black (KB) through a simple ultrasonic process, followed by high-temperature melting to yield the sulfur-containing composite, S@V 2 O 5 /KB. Constant current discharge tests demonstrated that the addition of KB as a conductive agent significantly improved the performance of the battery. The optimal performance was achieved when the mass ratio of V 2 O 5 to KB was 2:1. After 100 cycles at a rate of 0.5C, the capacity of 678.3 mA h g −1 was retained, resulting in a capacity retention rate of 71.67%.