A Pseudolayered MoS₂ as Li-Ion Intercalation Host with Enhanced Rate Capability and Durability

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Interlayer expansion in molybdenum disulfide (MoS2) improves lithium-ion (Li-ion) diffusion but reduces structural stability.
• Developing stable and high-performance Li-ion battery hosts is crucial for energy storage.

Purpose of the Study:

• To prepare an oxygen-incorporated MoS2 (O-MoS2)/graphene composite as a self-supported intercalation host for Li-ion.
• To investigate the structural stability and electrochemical performance of the O-MoS2 host.

Main Methods:

• Synthesis of O-MoS2/graphene composite.
• Electrochemical testing including rate capability and cycling stability.
• Ex situ X-ray diffraction (XRD) and density functional theory (DFT) calculations.

Main Results:

• The O-MoS2/graphene composite achieved a specific capacity of 80 mAh g-1 in 36 s and maintained over 91% capacity after 3000 cycles.
• O-MoS2 exhibited a dominant 1T phase with expanded layer spacing (10.15 Å), enhancing Li-ion intercalation kinetics.
• DFT calculations revealed that MoOx(OH)y pillars in O-MoS2 interlayers stabilize the structure by tensing MoS2 layers, preventing exfoliation.

Conclusions:

• The O-MoS2/graphene composite demonstrates a pseudolayered structure, offering remarkable durability and outstanding rate capability as a Li-ion intercalation host.
• Oxygen incorporation effectively addresses the trade-off between kinetics and stability in MoS2-based battery materials.