Phase evolution of lithium intercalation dynamics in 2H-MoS₂.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDs) exhibit tunable properties via ion intercalation.
• Understanding structural transformations during intercalation is key for advanced applications.

Purpose of the Study:

• Investigate the structural transformation dynamics of 2H-molybdenum disulfide (MoS2) upon electrochemical lithium-ion (Li+) intercalation.
• Elucidate the phase transition mechanism and its impact on material properties.

Main Methods:

• Electrochemical Li+ intercalation of 2H-MoS2.
• Raman spectroscopy and photoluminescence (PL) spectroscopy.
• Nudged elastic band (NEB) calculations and high-resolution transmission electron microscopy (HR-TEM).

Main Results:

• Li+ intercalation induces a phase transition from 2H-MoS2 to a dT phase, evidenced by Raman spectroscopy.
• Further Li+ insertion leads to single-layer-like MoS2.
• Photoluminescence emission redshifts and diminishes in the dT-MoS2 phase.
• A 2H-1T-dT phase transition mechanism for Li+-intercalated MoS2 is proposed.

Conclusions:

• Lithium intercalation drives significant structural and property changes in MoS2.
• The Li-stabilized dT-MoS2 phase offers potential for optoelectronic devices and Weyl state tuning.
• This research deepens the understanding of phase engineering in TMDs for technological applications.