Novel 2D Sb2S3 Nanosheet/CNT Coupling Layer for Exceptional Polysulfide Recycling Performance

2D layer-structured materials are considered a promising candidate as a coupling material in lithium sulfur batteries (LSBs) due to their high surface-volume ratio and abundant active binding sites, which can efficiently mitigate shuttling of soluble polysulfides. Herein, an electrochemical Li intercalation and exfoliation strategy is used to prepare 2D Sb2S3 nanosheets (SSNSs), which are incorporated onto a separator in LSBs as a new 2D coupling material for the first time. The cells containing a rationally designed separator which is coated with an SSNS/carbon nanotube (CNT) coupling layer deliver a much improved specific capacity with a remarkable 0.05% decay rate for over 200 cycles at a current density of 2 C. The capability of the SSNSs to entrap polysulfides through their favorable interfacial functionality and the high electrical conductivity of the CNT network facilitates recycling of active materials. The first-principle calculations verify the important roles of SSNSs, which demonstrate ideal binding strengths (1.33-2.14 eV) to entrap Li2Sx as well as a low-energy barrier (189 meV) for Li diffusion. These findings offer new insights into discovering novel coupling layers for high-performance LSBs and shed new light on the application of 2D layer-structured materials in energy storage systems.