Promoting kinetics of polysulfides redox reactions by the multifunctional CoS/C/CNT microspheres for high-performance lithium-sulfur batteries

Abstract The commercialization of sulfur cathodes has encountered several problems, including migration of polysulfide intermediates, low conductivity of sulfur and its discharge products, and volumetric changes in the cathode. To alleviate these problems, researchers have proposed a number of strategies, such as porous carriers, polysulfides sorbents, catalysts and conductive fillers. In this study, a novel CoS/C/CNT sulfur carrier material has been prepared by spray drying method to promote the performance of sulfur cathode according to the design idea of integrating various functions into one structure. The CoS/C/CNT can effectively adsorb polysulfides and catalyze their conversion. Simultaneously, the porous structure of the C/CNT conductive frame can improve the conductivity of the S-CoS/C/CNT composites, offer sufficient space to accommodate the necessary volume expansion of S and play a role in the physical limitation of polysulfides. Due to these multifunctional advantages in one structure, the obtained CoS/C/CNT shows a strong interaction with polysulfides and catalyzes the conversion of polysulfides. Finally, the obtained S-CoS/C/CNT composite cathode exhibits excellent electrochemical performance.