A Fast and Universal Approach to Encapsulating Transition Bimetal Oxide Nanoparticles in Amorphous Carbon Nanotubes under Atmospheric Environment based on Marangoni Effect.

Transitionmetal oxides nanoparticles capsuled in amorphous carbon nanotubes (ACNTs) are attractive anode materials of lithium ion batteries (LIBs). Here we firstly designed a fast and universal method with a hydromechanics conception which is called Marangoni flow to fabricating transition bimetal oxides (TBOs) in ACNTs composite with a better electrochemistry performance. Maragoni flows can produce a liquid column with several centimeters high in a tube with one side immersion 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 control the viscosity of a solution. In order to show our method could be general used, we synthesis two anode materials such as (a)CoFe2O4@ACNTs, (b) NiFe2O4@ACNTs. All of these have a similar morphology which is ~20 ?m length and with a diameter of 80-100 nm of the ACNTs and the particles (inside ACNTs) is smaller than 5 nm. Specially there are amorphous carbon between the nanoparticle. All the composite materials showed outstanding electrochemistry performance which have a high capacity and cycling stability for what after 600 cycle the capacity changed less than 3%.