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

As a popular strategy, interlayer expansion significantly improves the Li-ion diffusion kinetics in the MoS₂ host, while the large interlayer spacing weakens the van der Waals force between MoS₂ monolayers, thus harming its structural stability. Here, an oxygen-incorporated MoS₂ (O-MoS₂)/graphene composite as a self-supported intercalation host of Li-ion is prepared. The composite delivers a specific capacity of 80 mAh g⁻¹ in only 36 s at a mass loading of 1 mg cm⁻², and it can be cycled 3000 times (over 91% capacity retention) with a 5 mg cm⁻² loading at 2 A g⁻¹. The O-MoS₂ exhibits a dominant 1T phase with an expanded layer spacing of 10.15 Å, leading to better Li-ion intercalation kinetics compared with pristine MoS₂. Furthermore, ex situ X-ray diffraction tests indicate that O-MoS₂ sustains a stable structure in cycling compared with the gradual collapse of pristine MoS₂, which suffers from excessive lattice breathing. Density functional theory calculations suggest that the MoO_x(OH)_y pillars in O-MoS₂ interlayers not only expand the layer spacing, but also tense the MoS₂ layers to avoid exfoliation in cycling. Therefore, the O-MoS₂ shows a pseudolayered structure, leading to remarkable durability besides the outstanding rate capability as a Li-ion intercalation host.