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

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

The MoO x(OH) y pillars in O‐MoS2 interlayers lead to a pseudolayered structure with an expanded layer spacing of 10.15 Å, much larger than the value of pristine MoS2 (6.27 Å). The larger interlayer spacing leads to better Li‐ion intercalation kinetics. Meantime, the pillars can also tense the expanded MoS2 layers to avoid exfoliation during Li‐ion intercalation/deintercalation. Abstract 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.

Published in: "Small".

2018-11-07T08:34:58+00:00November 7th, 2018|Categories: Publications|Tags: , |
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