Effects of Fiber Diameter on Sulfur Loading and Lithium-Sulfur Battery Performance of Semicarbonized and Sulfurized Polyacrylonitrile Cathode Materials

With the rapid development of portable electronic devicesand electricvehicles, higher demands are placed on energy storage systems, andsulfurized polyacrylonitrile (SPAN) cathode materials have becomethe focus of research due to their excellent theoretical specificcapacity and other advantages. The magnitude of sulfur content ofthe active substance in SPAN cathode material is the key issue todetermine the electrochemical performance of lithium-sulfurbatteries. In this paper, we investigate the effects of fiber diametersof SPAN fibers as cathode materials on the sulfur content in SPANand the performance of batteries. At the same low molecular weight,the finer the fiber diameter, the larger the specific surface area,the higher the sulfur content in SPAN. When the fiber diameter is0.5 & mu;m, the sulfur content is about 47 wt %. The first reversibledischarge specific capacity at 0.2 C can reach 1284 mAh g(-1) (sulfur), and the capacity retention is about 92% after200 cycles. The reduced fiber diameter is beneficial to the formationof a stable structure for electron conduction, which shortens thelithium-ion transfer distance, reduces the charge transfer resistance,and improves the kinetics of the redox reaction. It also effectivelyalleviates cell polarization during charging and discharging and providescontrolled and optimized conditions for obtaining high-capacity andhigh-property Li/SPAN materials.

Automated summary

With the development of portable electronic devices and electric vehicles, the demand for energy storage systems has increased. Sulfurized polyacrylonitrile (SPAN) cathode materials have been extensively researched for their high specific capacity. In this study, the effects of fiber diameter on the sulfur content and performance of SPAN cathode materials were investigated. It was found that finer fiber diameter led to higher sulfur content and improved battery performance.