Superior electrochemical properties of MoS2 powders with a MoS2@void@MoS2 configuration

Abstract

Yolk-shell MoS2 powders with a distinct configuration of MoS2@void@MoS2 were prepared for the first time by applying spray pyrolysis. The yolk-shell MoO3 powders prepared by spray pyrolysis were converted into MoS2 powders by a simple sulfidation process at 400 °C without altering the morphology. Dense structured MoS2 powders were also prepared by a similar process. The respective initial discharge capacities of the yolk-shell and dense structured MoS2 powders at a current density of 1000 mA g(-1) were 651 and 490 mA h g(-1), and the corresponding capacity retentions after 100 cycles measured from the second cycle were 100 and 72%.

Enhanced Li+ storage properties of few-layered MoS2-C composite microspheres embedded with Si nanopowder

“…[12][13][14][15][16][17][18][19][20][21]. The third anodic peak is observed at a voltage of 2.3 V, corresponding to the conversion reaction of metallic Mo and Li 2 S to MoS 2 [52][53][54][55][56]. From the second cycle onward, the reduction and oxidation peaks overlap considerably, indicating the excellent reversible cycling performance of the MoS 2 -C composite microspheres with 30 wt.% Si.…”

“…Figure 4(a) shows the cyclic voltammogram curves of the composite microspheres with 30 wt.% Si during the first four cycles at a scan rate of 0.1 mV·s -1 in the voltage range of 0.001-3 V. Three reduction peaks resulting from Li + insertion into MoS 2 and Si were observed in the first cathodic scan. The first reduction peak located at 1.4 V is attributed to the intercalation of Li + into the hexagonal MoS 2 lattice, followed by the phase transformation to octahedral Li x MoS 2 [44][45][46][47][52][53][54][55][56]. The peak at around 0.6 V corresponds to the conversion reaction, in which Li x MoS 2 decomposes into metallic Mo nanocrystals embedded in a Li 2 S matrix, and the formation of a SEI layer on the MoS 2 -C surface, resulting from electrochemically driven electrolyte degradation [44][45][46][47][52][53][54].…”

“…The first reduction peak located at 1.4 V is attributed to the intercalation of Li + into the hexagonal MoS 2 lattice, followed by the phase transformation to octahedral Li x MoS 2 [44][45][46][47][52][53][54][55][56]. The peak at around 0.6 V corresponds to the conversion reaction, in which Li x MoS 2 decomposes into metallic Mo nanocrystals embedded in a Li 2 S matrix, and the formation of a SEI layer on the MoS 2 -C surface, resulting from electrochemically driven electrolyte degradation [44][45][46][47][52][53][54]. The third reduction peak located at 0.05 V is attributed to the reaction forming Li-Si alloys [12][13][14][15][16][17][18][19][20][21].…”

“…4(c)) have values above 99.5% from the 2 nd cycle. The Li + storage properties of these MoS 2 -C composite microspheres were compared with those of MoS 2 powders prepared by the spray pyrolysis process reported in the previous literature [52]. The bare MoS 2 powders with filled and yolk-shell structures had discharge capacities of 362 and 687 mAh·g -1 for the 100 th cycle, respectively, at a current density of 1 A·g -1 .…”

Sodium‐Doped Mesoporous Ni2P2O7 Hexagonal Tablets for High‐Performance Flexible All‐Solid‐State Hybrid Supercapacitors

“…[43] Second, during the cycling process, the doped Na acts as ap illar to prevent the collapse of the crystal, similar to the doping of Zn in Ni-MOF. [21] Third, the Na-doped Ni 2 P 2 O 7 hexagonal tablets can provide pores that should be favorable for diffusion of the electrolyte and the porouss tructure can effectively buffert he volume variation induced during the charge-discharge process,w hile the hexagonal tablets with their micrometer dimensions prevent undesirable agglomeration and ensure the stability of the porous structure.…”