Preparation method for silicon-carbon composite nano tube array

Abstract

The invention belongs to the field of lithium ion batteries and discloses a preparation method for a silicon-carbon composite nano tube array. The preparation method for the silicon-carbon composite nano tube array is characterized by comprising the following steps: raising the temperature of a porous-anode aluminum oxide template under inert gas; introducing acetylene gas; generating a carbon nano tube array on the surface of the template by high-temperature gas-phase decomposition of acetylene; vacuumizing and introducing the inert gas, hydrogen and silane after the temperature is raised; decomposing silane to obtain a coaxial carbon nano tube and silicon nano tube array in the template; and removing silicon oxide on the surface of the template by using a hydrofluoric acid aqueous solution and drying to obtain the silicon-carbon composite nano tube array. According to the preparation method for the silicon-carbon composite nano tube array, the silicon-carbon composite nano tube array with controllable pipe diameter, pipe length and wall thickness, and uniform size can be obtained by two-step chemical vapor deposition and hydrofluoric acid corrosion; in a whole production process, complicated equipment is not used and process steps are simple, so that large-scale industrial production is facilitated; the stability of the silicon-carbon composite nano tube array is good.

Description

(1) Technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a method for preparing a silicon-carbon composite nanotube array. (2) Background technology [0002] Lithium-ion batteries have played an important role in our lives thanks to their long cycle life and high specific capacity since they were invented; especially with the intensification of energy shortages and the deepening of people's use of new energy, we are increasingly The more energy storage devices that can be charged and discharged on a large scale are needed, the lithium-ion battery has become the preferred energy storage device due to its mature technology and excellent performance in all aspects. However, as an energy storage device, the specific capacity of lithium-ion batteries is not large enough, so how to effectively improve the specific capacity of lithium-ion batteries is the main scientific research goal at this stage. Silicon atoms can combine up t...

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Problems solved by technology

[0004] Cui et al. (M.-H.Park, M.G.Kim, J.Joo, K.Kim, J.Kim, S.Ahn, Y.Cui and J.Cho.Nano Lett. 2009, 9, 3844) used a porous anode Alumina templates are used to prepare silicon nanotubes as the negative electrode material of lithium-ion batteries, and the specific capacity of 2500mAh / g can still be maintained after 200 cycles; however, it is expensive, harsh conditions, poor reproducibility, and difficult to mass-produce

Chinese patent CN102983311A discloses the "preparation method of carbon nanotube-silicon composite negative electrode material". First, carbon nanotubes are prepared into carbon nanotube films, and then silane is decomposed in high-temperature gas phase to deposit a layer of silicon on the surface of carbon nanotube films; but its The thickness of the product is relatively thin, which requires precise instrument measurement. Silicon is coated on the outside of the carbon tube, and there are still problems of producing a large amount of solid electrolyte (solid electrolyte interface, SEI) film and cracking of silicon.

Chinese patent CN102354739A discloses "a silicon-carbon composite negative electrode material for lithium-ion batteries and its preparation method", which uses artificial graphite particles as the core material, and sequentially pyrolyzes silicon precursors and carbon precursors to coat a layer on the surface of artificial graphite particles Silicon and a layer of carbon form a core-shell material of carbon-silicon-carbon; however, the material has a low silicon content, and there is not enough space for the expansion of silicon, resulting in a low specific capacity and poor cycle performance

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