Self-Structured Binder Confinement of Sulfur for Highly Durable Lithium-Sulfur Batteries

Abstract

The lithium-sulfur battery (LSB) is a promising candidate for high-performance energy storage applications due to its high theoretical energy density and low cost. However, developing a highly durable sulfur cathode for LSBs has been challenging due to the known polysulfide shuttling and volume variation of sulfur that leads to chemical and mechanical degradation of the cathode during cycling. Sulfur confinement has become a promising solution to both issues. However, confining sulfur typically requires a complex and expensive process. Herein, we present a simple electrode processing method for producing highly durable sulfur cathodes with self-structured binder confinement for sulfur particles using only commercially available sulfur, carbon black, and binder, with no additional components. The dissolution of the binder is controlled during the slurry preparation step to form a porous binder/carbon shell structure around the sulfur particles that can entrap the soluble polysulfides and slow down the shuttling mechanism. The sulfur cathodes achieved through this method offer an outstanding capacity retention of 74% over 1000 cycles, a considerable reduction in the lithium-polysulfide shuttling and active material loss. Electrodes with a high areal loading of 7.37 mAh/cm2 (4.4 mg/cm2) also showed excellent cyclability as well as a high capacity of 800 mAh/g. The simplicity and cost-effectiveness of the presented method make it promising for the large-scale manufacturing of low-cost and durable sulfur cathodes, which pave the path to the commercialization of LSBs.