Unraveling the mechanism on improved kinetics performance of sulfurized polyacrylonitrile with defective conductive carbon matrix

Sulfurized polyacrylonitrile (SPAN) is considered as an ideal cathode material for next generation of lithium-sulfur (Li-S) batteries because of its unique solid–solid conversion mechanism to eliminate the shuttle effect in Li-S batteries. The deficient reaction kinetics resulting from the absence of a conductive network in SPAN constitutes a significant factor influencing its battery performance. Herein, defective Ketjen Black (D-KB) was used as the matrix of SPAN by a dissolution-precipitation process to recreate the internal conducting network of SPAN (SPAN@D-KB), consequently increasing its conductivity and improving the dynamic characteristics. Through rational defect-induced electron diffusion can benefit the dynamics in the solid phase of SPAN, and thus improves the overall electrochemical performance of the Li-S batteries. Therefore, the SPAN@D-KB electrodes delivered a high rate performance of 639 mAh gcomposite-1 at 3.0C, and a reversible capacity of 700 mAh gcomposite-1 at 0.2C with a capacity retention rate of 93% after 350cycles. This work offers theoretical guidelines for the design, preparation and performance optimization of SPAN materials, which is helpful to promote the future application of sulfur-based batteries.