CTAB-assisted synthesis of single-layer MoS₂–graphene composites as anode materials of Li-ion batteries

Abstract

A facile and scalable process was developed for the synthesis of single-layer MoS 2 -graphene nanosheet (SL-MoS 2 -GNS) composites based on the concurrent reduction of (NH 4 ) 2 MoS 4 and graphene oxide sheets by hydrazine in the presence of cetyltrimethylammonium bromide (CTAB), followed by annealing in a N 2 atmosphere. The morphology and microstructure of the composites were examined by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. The formation process for the SL-MoS 2 -GNS composites was also investigated. The SL-MoS 2 -GNS composites delivered a large reversible capacity and good cycle stability as a Li-ion battery anode. In particular, the composites easily surpassed MoS 2 in terms of rate performance and cycle stability at high current densities. Electrochemical impedance spectroscopy revealed that the GNS in the composite not only reduced the contact resistance in the electrode but also significantly facilitated the electron transfer in lithiation and delithiation reactions. The good electrochemical performance of the composites for reversible Li + storage could be attributed to the synergy between the functions of SL-MoS 2 and GNS.

MoS2-coated vertical graphene nanosheet for high-performance rechargeable lithium-ion batteries and hydrogen production

“…In the first discharge curve, there are two plateaus located at 1.2-1.1 and 0.8-0.5 V. The former is ascribed to the formation of Li x MoS 2 through lithium intercalation, and the latter is due to the conversion of MoS 2 into metallic Mo accompanied by the formation of the SEI layer. 1, 33 The MoS 2 /VGNS nanocomposites also exhibited an obvious plateau in the potential range between 2.0 and 2.4 V in the first charge cycle, corresponding to the oxidization of Li 2 S into S. 35 These discharge/charge behaviors are consistent with the CV curves shown in Figure 3a. Compared with the pristine VGNS and MoS 2 /CB control samples (Supplementary Figures S6b and S7b), MoS 2 /VGNS nanocomposites displayed longer flat plateaus, which may be attributed to the synergistic integration between MoS 2 and VGNS.…”

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS2/Nanotube Composite Lithium Ion Battery Electrodes

“…[20][21][22][23][24][25][26][27][28] Similar approaches involve mixing MoS2 with polyaniline nanowires 29 or carbon nanotubes. 19,[30][31][32] However, the composite electrodes described above remain far from optimised as LIB electrodes.…”

Review—Two-Dimensional Layered Materials for Energy Storage Applications

“…[12][13][14][27][28][29][30][31][32][33][34][35][36][37][38][39]55 Layer-by-layer stacked hetero-structures of graphene-TMDCs is also suggested as an effective way to overcome above mentioned issues. 14,31,[33][34][35] TMDCs for sodium ion batteries (SIBs).-Sodium ion batteries (SIBs) have emerged as an appealing alternative to LIBs because the resources of sodium metal are in principle unlimited in nature. Moreover, the ion transport mechanism of sodium resembles to lithium, thus the knowledge accrued for the development of LIBs could be directly applied to the SIBs.…”

“…[12][13][14][27][28][29][30][31][32][33][34][35][36][37][38][39] Graphene sheets can effectively restrict the restacking of TMDCs layers, provide better conductivity, enlarge effective surface area and improve the cycling stability. 12,14,27,31,33 Besides TMDCs, MXenes have become novel materials in the family of 2D materials, and are highly promising for lithium/sodium battery anodes as well as for capacitors and pseudo-capacitor applications. 20,22,23,25,26 Regardless of noteworthy development, more improvements are needed for practical applications.…”