Rechargeable lithium-ion batteries (LIBs) have attracted great attention in many fundamental applications due to their high energy and powder density, environmental benignity and long cycle life.¹In order to further increase the energy density and power capability of current LIBs, enormous efforts have been made to develop high-performance electrode materials.

In a typical reaction, 1 mmol (NH₄)₆Mo₇O₂₄·4H₂O, 15 mmol CH₄N₂S and 15 mmol CH₄N₂Se were dissolved in deionized water (35 mL) under vigorous stirring to form a homogeneous solution. Then, the solution was transferred into a 45 mL Teflon-lined stainless steel autoclave and maintained at 220 °C for 18 h. After being cooled to room temperature. The final precipitates were centrifuged and washed with water for several times and dried at 80°C under vacuum for 12 h.

Fig 1a shows the XRD pattern of 3D MoS₂/MoSe₂ nanosheets entanglement. The different diffraction peaks to the standard pattern of MoS₂ and MoSe₂ indicates the special entanglement structure. TEM and the corresponding high-magnification TEM images (Fig. 1b and c) reveal the uniform nanosheets entanglement of the 3D MoS₂/MoSe₂. More importantly, the corresponding liner element mapping indicates the uniform distribution of Mo, S and Se elements in the nanosheets entanglement, confirming the obtained uniform 3D entanglement architecture.

Fig 2a shows the typical discharge-charge profiles for the initial three cycles at 100 mA/g in the voltage window of 0.01 to 3 V. The initial discharge specific capacity is 1367.8 mAh/g. The discharge-charge cycling performance was evaluated at the current density of 100 mA/g and is shown in Figure 2b. For the 3D MoS₂/MoSe₂nanosheets entanglement, a high discharge specific capacity of ∼1234.3 mAh/g has been retained after 20 cycles.

Fig 1. (a) XRD pattern and (b) TEM image of the 3D MoS₂/MoSe₂nanosheets entanglement, (c) High-magnification TEM image corresponding to area 1 in (b), (d) Corresponding liner element mapping of (c).

Fig. 2. (a) Dischargeª¢charge voltage profiles of 3D MoS₂/MoSe₂ nanosheets entanglement. (b) Cycling performance of MoS₂/MoSe₂nanosheets entanglement.

In summary, the 3D MoS₂/MoSe₂nanosheets entanglement are successfully synthesized by a simple hydrothermal method. Moreover, this 3D interesting architecture shows greatly enhanced capacity and cycling performance when used as an anode material for LIBs

 

References:

[1] Kang B, Ceder G. Battery materials for ultrafast charging and discharging [J]. Nature, 2009, 458(7235): 190-193.