An innovative one-step hydrothermal approach for fabricating Ta₂O₅/WS₂@rGO heterostructure as a coated separator for Li–S batteries

Lithium-sulfur (Li–S) batteries, which use lightweight metallic lithium and cost-effective elemental sulfur as electrodes, have significant potential to achieve high energy density. Nevertheless, the shuttle effect and sluggish electrochemical kinetics have greatly hindered their commercialization. Here, a one-step hydrothermal method is employed to produce a new Ta₂O₅/WS₂@rGO heterostructure, which serves as an efficient functional separator for Li–S batteries. The computational results show that Ta₂O₅ effectively anchors polysulfides, reducing their dissolution into the electrolyte, while the highly conductive 2D WS₂ enhances electron transfer at the separator and displays strong polysulfide binding energies. The heterointerfaces between Ta₂O₅ and WS₂ may aid in the capture, dispersion, and conversion of LiPSs. The functional separator of Ta₂O₅/WS₂@rGO boosts the Li–S cell's capacity (at 2.0C) to 618 mAh g⁻¹ after 900 cycles, demonstrating excellent long-cycle performance and minimal capacity loss per cycle. Additionally, the Li–S cell utilizing Ta₂O₅/WS₂@rGO as a coated separator can retain 7.8 mAh cm⁻² of energy after 280 cycles, which occurs when the sulfur content rises to 7.3 mg cm⁻² under an (E/S) ratio of 6.0 μL mg⁻¹.