A designed nanostructure with MoS2 nanosheets (NSs) perpendicularly grown on graphene sheets (MoS2/G) is achieved by a facile and scalable hydrothermal method, which involves adsorption of Mo7O24(6-) on a graphene oxide (GO) surface, due to the electrostatic attraction, followed by in situ growth of MoS2. These results give an explicit proof that the presence of oxygen-containing groups and pH of the solution are crucial factors enabling formation of a lamellar structure with MoS2 NSs uniformly decorated on graphene sheets. The direct coupling of edge Mo of MoS2 with the oxygen from functional groups on GO (C-O-Mo bond) is proposed. The interfacial interaction of the C-O-Mo bonds can enhance electron transport rate and structural stability of the MoS2/G electrode, which is beneficial for the improvement of rate performance and long cycle life. The graphene sheets improve the electrical conductivity of the composite and, at the same time, act not only as a substrate to disperse active MoS2 NSs homogeneously but also as a buffer to accommodate the volume changes during cycling. As an anode material for lithium-ion batteries, the manufactured MoS2/G electrode manifests a stable cycling performance (1077 mAh g(-1) at 100 mA g(-1) after 150 cycles), excellent rate capability, and a long cycle life (907 mAh g(-1) at 1000 mA g(-1) after 400 cycles).

A unique watermelon-like structured SiO x -TiO 2 @C nanocomposite is synthesized by a scalable sol-gel method combined with carbon coating process. Ultrafine TiO 2 nanocrystals are uniformly embedded inside SiO x particles, forming SiO x -TiO 2 dual-phase cores, which are coated with outer carbon shells. The incorporation of TiO 2 component can effectively enhance the electronic and lithium ionic conductivities inside the SiO x particles, release the structure stress caused by alloying/dealloying of Si component and maximize the capacity utilization by modifying the Si-O bond feature and decreasing the O/Si ratio (x-value). The synergetic combination of these advantages enables the synthesized SiO x -TiO 2 @C nanocomposite to have excellent electrochemical performances, including high specific capacity, excellent rate capability, and stable long-term cycleability. A stable specific capacity of ≈910 mAh g −1 is achieved after 200 cycles at the current density of 0.1 A g −1 and ≈700 mAh g −1 at 1 A g −1 for over 600 cycles. These results suggest a great promise of the proposed particle architecture, which may have potential applications in the improvement of various energy storage materials.

Molybdenum disulfide (MoS2), which possesses a layered structure and exhibits a high theoretical capacity, is currently under intensive research as an anode candidate for next generation of Li‐ion batteries. However, unmodified MoS2 suffers from a poor cycling stability and an inferior rate capability upon charge/discharge processes. Herein, a unique nanocomposite comprising MoS2 nanothorns epitaxially grown on the backbone of carbon nanotubes (CNTs) and coated by a layer of amorphous carbon is synthesized via a simple method. The epitaxial growth of MoS2 on CNTs results in a strong chemical coupling between active nanothorns and carbon substrate via CS bond, providing a high stability as well as a high‐efficiency electron‐conduction/ion‐transportation system on cycling. The outer carbon layer can well‐accommodate the structural strain in the electrode upon lithium‐ion insertion/extraction. When employed as an anode for lithium storage, the prepared material exhibits remarkable electrochemical properties with a high specific capacity of 982 mA h g−1 at 0.1 A g−1, as well as excellent long‐cycling stability (905 mA h g−1 at 1 A g−1 after 500 cycles) and superior rate capability, confirming its potential application in high‐performance Li‐ion batteries.

No abstract

No abstract