Electrospun Micrometer-Sized Sulfur Fibers as an Active Material for Lithium Batteries

Abstract

We prepared micrometer-sized sulfur fibers by melt-electrospinning technique. The typical average size of the spun fibers was 17.8 μm in diameter. The XRD pattern of the as-spun sulfur fibers suggests that their crystal structure is polymeric sulfur. The polymeric sulfur structure of the fibers left at room temperature for 24 h changed to orthorhombic α-S8 structure. The coating process of the spun sulfur fibers with poly(pyrrole), PPy, was performed through oxidative coupling reaction of pyrrole by iodine. Coating of the sulfur fibers with PPy enhanced their electrochemical responses. The capacity of the PPy-coated spun sulfur fiber electrode in the lithium-sulfur test cell was 570 Ah kg-1 under constant current discharge condition (0.045C).