Interface engineering by atomically thin layer tungsten disulfide catalyst for high performance Li–S battery

Owing to high aspect ratio of edge sites and superior catalytic activity, atomically thin transition metal dichalcogenides (TMDCs) show great promise to tailor the electrolyte/electrode interface properties for high performance lithium-sulfur battery (Li–S battery). However, the TMDCs that engineer the electrode/electrolyte interface are usually produced through chemical hydrothermal methods, which show low crystallinity and thick multilayer structure. Herein, a highly crystalline and atomically thin tungsten disulfides on carbon cloth (WS₂@CC) was developed via chemical vapor deposition (CVD) and served as an effective electrode/electrolyte interface for Li–S battery. Our results demonstrate that the atomically thin WS₂ with high crystal quality and abundant edges sites can effectively accelerates the redox kinetics of sulfur/lithium polysulfides and regulates the precipitation/decomposition of insoluble Li₂S. More importantly, it was revealed that the hierarchical flower-stacked WS₂ with excessive exposed catalytic edges shows extremely strong polysulfide adsorption, which causes the sulfur species aggregation and passivation on the WS₂@CC surface, thus resulting in deformed rate performance and poor cycling stability as compared to the few-layer WS₂@CC. Our work provides a new insight into the structural engineering of TMDCs by CVD for Li–S battery, and suggests the importance of rational chemisorption and catalysis of the interface to realize the high-performance Li–S battery.