Observation of an intermediate state during lithium intercalation of twisted bilayer MoS2

Abstract

Lithium intercalation of MoS2 is generally believed to introduce a phase transition from H phase (semiconducting) to T phase (metallic). However, during the intercalation process, a spatially sharp boundary is usually formed between the fully intercalated T phase MoS2 and non-intercalated H phase MoS2. The intermediate state, i.e., lightly intercalated H phase MoS2 without a phase transition, is difficult to investigate by optical-microscope-based spectroscopy due to the narrow size. Here, we report the stabilization of the intermediate state across the whole flake of twisted bilayer MoS2. The twisted bilayer system allows the lithium to intercalate from the top surface and enables fast Li-ion diffusion by the reduced interlayer interaction. The E2g Raman mode of the intermediate state shows a peak splitting behavior. Our simulation results indicate that the intermediate state is stabilized by lithium-induced symmetry breaking of the H phase MoS2. Our results provide an insight into the non-uniform intercalation during battery charging and discharging, and also open a new opportunity to modulate the properties of twisted 2D systems with guest species doping in the Moiré structures.

High-Performance MoS2/SWCNT Composite Films for a Flexible Thermoelectric Power Generator

“…In addition, three characteristic peaks were visible at J 1 , J 2 , and J 3 , and the 1T phase exhibited a zone-folding process. These three peaks were assumed to be caused by MoS 2 , indicating that the prepared MoS 2 was a mixed phase. ,, The Raman spectra of SWCNTs had a weak D-band at 1343 cm –1 and a strong G-band at 1596 cm –1 . The G-band is characteristic of the in-plane stretching vibration of sp 2 hybrid carbon atoms, whereas the D-band is connected to the resonant scattering generated by structural flaws.…”

“…Earth-abundant molybdenum disulfide (MoS 2 ), an inorganic compound with a stable semiconducting 1H phase and a sub-stable metallic 2T phase, has been considered as a promising candidate for TE applications due to its high S (≈10 mV K –1 ). − However, MoS 2 has a low electrical conductivity (≈2.2 × 10 –6 S cm –1 ) . Guo et al reported that pressure-induced semiconductor/metal transition was beneficial for improving the electrical conductivity .…”

Activation of MoS2 monolayer electrocatalysts via reduction and phase control in molten sodium for selective hydrogenation of nitrogen to ammonia

“…3f that the monolayer catalyst shows a very similar ECSA value and that the 1T/2H interfacial junctions could have a positive effect on promoting both the NRR and HER kinetics. 17,20,26…”

“…The abundant saturated coordinative atoms in the base planes, on the other hand, are inactive and the overall catalytic efficiency is severely slowed by a deficiency of active sites on the basical plane. 20 To this end, defect, phase and strain engineering have been explored to boost the intrinsic activity of MoS 2 catalysts. 21–24 However, their poor conductivity and inert basal planes result in NH 3 yield rates that are generally less than 50 μg h −1 mg cat −1 , such as 13.09 μg h −1 mg cat −1 for MoS 2 nanosheets and 29.28 μg h −1 mg cat −1 for defect-rich 2H-MoS 2 nanoflowers.…”

SERS-based detection of efficient removal of organic dyes using molybdenum dichalcogenide nanostructures

“…In the 2H phase of MoS 2 , the Mo atom is surrounded in trigonal prismatic coordination with two S-Mo-S units per elemental cell [20]. Considerable effort has been made to study the H-phase MoS 2 in the fields of electronics, photonics, and photo-catalytic chemistry [21]. Molybdenum selenide (MoSe 2 ) has also been extensively researched due to its strong absorption of sunlight and unique band structure while molybdenum telluride (MoTe 2 ) is gaining interest in electronic and optoelectronic devices [22].…”