High-yield exfoliation of NbSe2 through optimized lithium-ion intercalation and its application in electromagnetic-interference shielding

Abstract

A class of next-generation two-dimensional material, transition-metal dichalcogenides (TMDCs) have attracted attention because of their versatile properties ranging from metals and semiconductors to insulators. Among them, NbSe2 is a metallic TMDC and has substantial potential to energy and electronics fields. However, there are less studies on NbSe2 such as synthesis/preparation and applications compared to MoS2 or WSe2. To use the intrinsic super conductivity of NbSe2 greatly, increasing exposed surfaces of layered bulk nanomaterial is a key role by exfoliating the layered bulk structures into a single or few layered materials. In this work, lithium (Li)-ion intercalation-assisted exfoliation that able to expand interlayer spacing dramatically was performed to obtain mono layers of NbSe2. Since few research has revealed the optimized intercalation conditions, we suggest our own strategy for a high-yield production of NbSe2 monolayers. To achieve nanosheets with high yields, the optimal process was obtained by adjusting the Li intercalation condition such as driving source, temperature, and power. Finally, the highest efficiency parameter was determined by monitoring the concentration of NbSe2 dispersion. Then, the electromagnetic interference shielding effectiveness (SE) was measured based on the electrical conducting nature of NbSe2. The highest SE was measured to 20 dB at low amounts (similar to 1.65 mg).