Boosting solid–solid conversion kinetics of sulfurized polyacrylonitrile via MoS2 doping for high‐rate and long‐life Li‐S batteries

Abstract

Abstract Sulfurized polyacrylonitrile (SPAN) with a “solid‐solid” conversion mechanism in carbonated‐based electrolyte eradicating the polysulfides shutting issue is considered as an ideal cathode for stabilizing lithium–sulfur (Li‐S) batteries. However, the sluggish reaction kinetics and less sulfur content of the SPAN limit its practical application. Herein, the MoS2 doped SPAN (MoS2@SPAN) is demonstrated to rapidly accelerate the solid–solid conversion kinetics of SPAN for remarkably boosting high‐power and long‐life Li‐S batteries. Benefitting from the accelerated lithium‐ion (Li+) transfer rate, a fast ion transport channel and enhanced redox reaction kinetics of sulfur to Li2S2/Li2S is realized via MoS2 catalysis, and excellent electrochemical performance is achieved. Consequently, MoS2@SPAN delivers a high capacity of 626 mAh g−1 at 0.1 A g−1, and simultaneously shows ultralong cycling life of 500 cycles with only 0.089% capacity decay rate at 2 A g−1. Moreover, a superb capacity of 321 mAh g−1 at ultrahigh current density of 5 A g−1 is offered, outperforming most of the reported SPAN cathodes. This work provides a general and reliable strategy on the reliable design of SPAN cathode for high‐rate and long‐term Li‐S batteries.

Keywords

• high‐rate
• lithium‐sulfur batteries
• MoS2
• “solid‐solid” conversion
• sulfurized polyacrylonitrile