Li-Ion Intercalated Exfoliated WS2 Nanosheets with Enhanced Electrocatalytic Hydrogen Evolution Performance

Tungsten disulfide (WS2) as a 2D layered material shows good application in the field of electrocatalysis due to its unique 2D structure, excellent electronic properties, and catalytic activity. However, the electrocatalytic performance of bulk WS2 materials is limited due to the lack of active sites. Hence, a few layers of WS2 nanosheets are prepared by a simple method of lithium (Li)-ion intercalation exfoliation, and enhanced electrocatalytic hydrogen evolution performance is demonstrated compared to bulk WS2. This method can not only realize the large-scale preparation of WS2 nanosheets, but also the obtained WS2 nanosheets have a larger lateral size, a good lattice structure, and no chemical impurities remain. Most importantly, it is realized that the reduction in the thickness of WS2 nanosheets will generate additional active sites from the ultrathin planar structure, thereby improving electrocatalytic activity. The exfoliated WS2 nanosheets show a smaller overpotential compared to the bulk WS2, the overpotential is about 320 mV at 10 mA cm(-2). This work shows that Li-ion intercalation exfoliated method is an efficient strategy to prepare 2D nanosheets materials and effectively improve its electrocatalytic performance.