Synthesis of 1T-MoS2 sheets with large space distance between layers for high-rate aqueous Zn-ion batteries cathode

Abstract

Molybdenum disulfide (MoS2), as a classical layered transition-metal dichalcogenide (TMD), shows great potential as an advanced Zn2+ storage cathode of aqueous Zn-ion batteries (ZIBs) due to high theoretical capacity and two-dimensional Zn2+ transport channels. However, the narrow interlayer distance and the poor electrical conduction of stable 2H-MoS2 limit its applications. In this work, the 1T-MoS2 sheets with good electrical conduction and large interlayer spacing of 9.5 Å (designated as MoS2-180) have been successfully prepared by a facile hydrothermal method. The interlaminar structural water induces stable existence of metastable 1T-MoS2 and large space distance of 6.08 Å between layers (that is larger than the size (5.5 Å) of hydrated Zn2+), and contributes to its excellent hydrophilicity, promoting transmission of hydrated Zn2+. The interlayer spacing-tailored MoS2-180 cathode exhibits high specific capacity (Cs) of 226.2 mAh g−1 at 0.10 A g−1 and impressive high-rate capability. The Cs at 5.00 A g−1 is extraordinarily up to 150.9 mAh g−1 and retains 66.7% of that at 0.10 A g−1. This is far superior to the most reported MoS2, MoS2 derivatives and MoS2/C composite cathodes. Moreover, the activated MoS2-180 cathode shows robust long-term cycling stability with Cs retention of 103.6% after 500 cycles at 1.00 A g−1. The mechanism behind these phenomena brings new insights into the structural water-induced 1T-MoS2 for high-performance aqueous ZIBs cathodes.