Composites of carbon nanotube and protonated montmorillonite as structural and chemical dual-encapsulation sulfur carrier for lithium-sulfur battery

Abstract

Lithium-sulfur (Li–S) battery is considered as a promising next-generation energy storage system because of its high energy density and low cost. However, their practical applications still face the challenges of shuttle effect and electrical conductivity. Here in, we prepared low-layer protonated montmorillonite (H-MMT) and carbon nanotube (CNT) composites (MCNT12) as sulfur carriers. H-MMT provides polar adsorption, CNT provides good conductivity, furthermore the combination of the two materials can obtain larger specific surface area and pore volume. Because of these favorable properties, the cathode material MCNT12/S has excellent electrochemical performance, exhibiting excellent cycle ability at 1C with capacity of 654 mAh/g over 500 cycles, and the average capacity decay rate of each cycle is only 0.05%, indicating the material has high rate cycle stability. Moreover, the adsorption mechanism of H-MMT for lithium polysulfide is further discussed, and the excellent performance of H-MMT in lithium sulfur battery will promote the further application of mineral materials in electrochemical energy storage materials.