Structural and chemical characterization of MoO2/MoS2 triple-hybrid materials using electron microscopy in up to three dimensions

This work presents the synthesis of MoO₂/MoS₂ core/shell nanoparticles within a carbon nanotube network and their detailed electron microscopy investigation in up to three dimensions. The triple-hybrid core/shell material was prepared by atomic layer deposition of molybdenum oxide onto carbon nanotube networks, followed by annealing in a sulfur-containing gas atmosphere. High-resolution transmission electron microscopy together with electron diffraction, supported by chemical analysis via energy dispersive X-ray and electron energy loss spectroscopy, gave proof of a MoO₂ core covered by few layers of a MoS₂ shell within an entangled network of carbon nanotubes. To gain further insights into this complex material, the analysis was completed with 3D electron tomography. By using Z-contrast imaging, distinct reconstruction of core and shell material was possible, enabling the analysis of the 3D structure of the material. These investigations showed imperfections in the nanoparticles which can impact material performance, i.e. for faradaic charge storage or electrocatalysis.

Recent Progress of Electrochemical Energy Devices: Metal Oxide–Carbon Nanocomposites as Materials for Next-Generation Chemical Storage for Renewable Energy

With the importance of sustainable energy, resources, and environmental issues, interest in metal oxides increased significantly during the past several years owing to their high theoretical capacity and promising use as electrode materials for electrochemical energy devices. However, the low electrical conductivity of metal oxides and their structural instability during cycling can degrade the battery performance. To solve this problem, studies on carbon/metal-oxide composites were carried out. In this review, we comprehensively discuss the characteristics (chemical, physical, electrical, and structural properties) of such composites by categorizing the structure of carbon in different dimensions and discuss their application toward electrochemical energy devices. In particular, one-, two-, and three-dimensional (1D, 2D, and 3D) carbon bring about numerous advantages to a carbon/metal-oxide composite owing to the unique characteristics of each dimension.

Three-dimensional mesoporous sandwich-like g-C3N4-interconnected CuCo2O4 nanowires arrays as ultrastable anode for fast lithium storage

Inspite of their impressive high theoretical capacity as Lithium-ion batteries (LIBs) anodes, spinel transition-metal oxides (TMOs) suffer serious volume expansion, aggregation and the pulverization of crystal structures during lithiation/delithiation, and this process severely restrict their industrial application. Multi-dimensional morphological engineering of spinel TMO nanostructures is an effective way to solve this issue. In this work, using facile hydrothermal synthetic methods, spinel CuCo₂O₄ nanowires arrays are synthesized and supported on g-C₃N₄ nanosheets, thus forming a unique sandwich-like interconnected three-dimensional mesoporous structure containing high amount of void spaces. Addition of g-C₃N₄ nanosheets to CuCo₂O₄ nanowire arrays may shorten the Li⁺ diffusion distance and electron transfer pathway, and may also provide more active sites for Li⁺ diffusion into electrolyte and buffer for the volume expansion and aggregation of CuCo₂O₄. As a LIB anode material, CuCo₂O₄@g-C₃N₄ shows initial lithiation capacity of 840.6 mAh g^-1, and capacity retention of 641.2 mAh g^-1 after 60 cycles at the current density of 0.1 A g^-1 and 499.2 mAh g^-1 after 40 cycles at high current of 1 A g^-1, which is significantly better than value of pure CuCo₂O₄ nanowires. This work affords a new way to tackle the problem of volume expansion of high capacity spinel TMO anode materials using g-C₃N₄ nanosheets as buffering agent.

Controllable growth of MnOx dual-nanocrystals on N-doped graphene as lithium-ion battery anode

Nanocomposites containing Mn₃O₄ and MnOOH dual-nanocrystals on N-doped graphene sheets were prepared as LIBs anode using a solvothermal method.

Microwave regeneration of spent activated carbon for the treatment of ester-containing wastewater

In this study, an integrated granular activated carbon (GAC) adsorption/microwave (MW) irradiation process was used for the treatment of ester-containing wastewater from a lithium-ion battery (LIB) factory.

Enhanced electrochemical performances of MoO2 nanoparticles composited with carbon nanotubes for lithium-ion battery anodes

Lab-made CNT nanocomposites decorated with MoO₂ nanoparticles (MoO₂/CNTs) demonstrated superior cycling and rate performances as LIB anode materials.