The research team was led by Dr. Zeng Zhiyuan, Assistant Professor in CityU's Department of Materials Science and Engineering (MSE), in collaboration with scientists from the University of Montpellier and Ulsan National Institute of Science and Technology (UNIST). Their findings were published in the academic journal Nature Protocols, under the title "High-yield production of mono- or few-layer transition metal dichalcogenide nanosheets by an electrochemical lithium ion intercalation-based exfoliation method."

A simple method that offers a higher degree of control

Previously, TMD nanosheets can be produced by a chemical method called lithium ion intercalation-based exfoliation. Intercalation means the insertion of a molecule or ion into materials that have layered structures. If every layer is intercalated with lithium ions, then materials with monolayers will be produced after ultrasound sonication and exfoliation; if only parts of the layers are intercalated with lithium ions, then the result will be bi- or few-layer products.

However, this traditional chemical method needs to be carried out at a relatively high temperature up to 100 °C and for a long time, some may take three days. More importantly, it is difficult to control the amount of lithium insertion.