Self-Climbed Amorphous Carbon Nanotubes Filled with Transition Metal Oxide Nanoparticles for Large Rate and Long Lifespan Anode Materials in Lithium Ion Batteries

A composed material of amorphous carbon nanotubes (ACNTs) and encapsulated transition metal oxide (TMOs) nanoparticles was prepared by a common thermophysics effect, which is named the Marangoni effect, and a simple anneal process. The prepared ropy solution would form a Marangoni convection and climb into the channel of anodic aluminum oxide template (AAO) spontaneously. The ingenious design of the preparation method determined a distinctive structure of TMOs nanoparticles with a size of ∼5 nm and amorphous carbon coated outside full in the ACNTs. Here we prepared the ferric oxide (Fe₂O₃) nanoparticles and Fe₂O₃ mixed with manganic oxide (Fe₂O₃&Mn₂O₃) nanoparticles encapsulated in ACNTs as two anode materials of lithium ion batteries’ the TMOs-filled ACNTs presented an evolutionary electrochemical performance in some respects of highly reversible capacity and excellent cycling stability (880 mA h g^–1 after 150 cycles)

Fast and Universal Approach to Encapsulating Transition Bimetal Oxide Nanoparticles in Amorphous Carbon Nanotubes under an Atmospheric Environment Based on the Marangoni Effect

Transition metal oxide nanoparticles capsuled in amorphous carbon nanotubes (ACNTs) are attractive anode materials of lithium-ion batteries (LIBs). Here, we first designed a fast and universal method with a hydromechanics conception which is called Marangoni flow to fabricate transition bimetal oxides (TBOs) in the ACNT composite with a better electrochemistry performance. Marangoni flows can produce a liquid column with several centimeters of height in a tube with one side immersed in the liquid. The key point to induce a Marangoni flow is to make a gradient of the surface tension between the surface and the inside of the solution. With our research, we control the gradient of the surface tension by controlling the viscosity of a solution. To show how our method could be generally used, we synthesize two anode materials such as (a) CoFe₂O₄@ACNTs, and (b) NiFe₂O₄@ACNTs. All of these have a similar morphology which is ∼20 μm length with a diameter of 80–100 nm for the ACNTs, and the particles (inside the ACNTs) are smaller than 5 nm. In particular, there are amorphous carbons between the nanoparticles. All of the composite materials showed an outstanding electrochemistry performance which includes a high capacity and cycling stability so that after 600 cycles the capacity changed by less than 3%

Flexible, Transparent, and Free-Standing Silicon Nanowire SERS Platform for in Situ Food Inspection

We demonstrated a flexible transparent and free-standing Si nanowire paper (SiNWP) as a surface enhanced Raman scattering (SERS) platform for in situ chemical sensing on warping surfaces with high sensitivity. The SERS activity has originated from the three-dimension interconnected nanowire network structure and electromagnetic coupling between closely separated nanowires in the SiNWP. In addition, the SERS activity can be highly improved by functionalizing the SiNWP with plasmonic Au nanoparticles. The hybrid substrate not only showed excellent reproducibility and stability of the SERS signal, but also maintained the flexibility and transparency of the pristine SiNWP. To demonstrate its potential application in food inspection, the Au nanoparticles-modified SiNWP was directly wrapped onto the lemon surface for in situ identification and detection of the pesticide residues. The results showed that the excellent SERS activity and transparency of the hybrid substrate enabled the detection of the pesticides down to 72 ng/cm², which was much lower than the permitted residue dose in food safety