Facile synthesis of graphene–molybdenum dioxide and its lithium storage properties

Abstract

Graphene-molybdenum dioxide composites in several ratios have been prepared through a facile synthesis method. Depending on the ratio, the as synthesized composites have either 2-dimensional graphene sheets with MoO 2 particles anchored to them or a clustered agglomerate morphology. The composites have been characterised using Raman spectroscopy, X-ray diffraction, and electron diffraction to confirm the monoclinic MoO 2 phase that is present. Lithium storage properties of the assynthesised samples were tested in a coin-type half cell assembly to determine the relationship between the ratio and the electrochemical performance. The sample with highest amount of MoO 2 (78 wt%) displayed the most promising lithium storage properties, with stable cycling performance at 0.2 A g À1 that shows negligible capacity loss over 50 cycles, retaining a capacity of 640 mA h g À1. The rate capabilities were also tested, and show a capacity of 380 mA h g À1 at 2.0 A g À1, which is comparable to the theoretical capacity of graphite and previously reported work on similar materials.

Ultrathin MoO2 nanosheets for superior lithium storage

“…Also, increased capacity is found when the electrodes are further cycled at a constant rate of 0.5 A g À 1 , implying a superior stability. Clearly, such MoO 2 /C nanosheets outperform any reported MoO 2 materials [5][6][7][9][10][11][12][13][14][18][19][20], and other oxides and chalcogenides such as MoO 3 /C microballs [35], MoS 2 nanosheets on CNT [36], and FeS/C nanosheets [37] (Supporting information Table S1), verifying effectiveness of our nanoengineering strategy. Figure 4b shows that the MoO 2 /C nanosheets can sustain rapid potential sweep, again proving their robust Li-storage behavior.…”

“…Recently, graphene supporting represents one of the ideal designs towards high-performance electrodes and has been extensively pursued. Nevertheless MoO 2 /graphene nanohybrids still suffered from kinetics barrier, affording a limited rate capability around 400 mAh g À 1 at a rate of 2 A g À 1 [18,19]. This might be related to breaking off of conducting pathways by the insulating Li 2 O phase and peeling off of active particles from graphene upon Li uptake in MoO 2 .…”

Rational confinement of molybdenum based nanodots in porous carbon for highly reversible lithium storage

“…1b shows a typical bright-field TEM (BF-TEM) image of molybdenum based nanoplate with an inset of the corresponding high resolution TEM (HR-TEM) image showing different lattice fringes related to both Zn 2 Mo 3 O 8 and MoO 2 (in blue and green colors, respectively). 25 A selected area electron diffraction (SAED) image is also presented in the inset of Fig. 1b, and diffuse rings can be indexed to the (002) and (112) planes of Zn 2 Mo 3 O 8 , as well as the (-111) and (-211) planes of MoO 2 .…”

The effects of FEC (fluoroethylene carbonate) electrolyte additive on the lithium storage properties of NiO (nickel oxide) nanocuboids

“…Similar phenomena have also been reported for other transition metal oxides. [40][41][42][43] The NiO nanocuboids were further tested for rate performance and the results are shown in Fig. 5(a) and (b).…”