Thermal plasma synthesis of Si-multi walled carbon nanotube nanocomposite as an anode for lithium-ion batteries

Abstract

The Si-MWCNT (multi-walled carbon nanotube) nanocomposite, which is considered a promising replacement for graphite as an anode material for lithium-ion batteries, was prepared using a triple DC thermal plasma jet system. We used micron-size silicon powder and MWCNT powder as raw materials. We varied the main parameters by mixing silicon and MWCNTs or individually injected into the plasma jet and adjusting the mass ratio to 2:1 and 1:2. The location of injection for the raw materials played a critical role in the formation of Si-MWCNT nanocomposites as the temperature at the injection site has a significant impact on the vaporization of silicon and sublimation of carbon nanotubes. Additionally, it was influenced by efficient heat transfer of silicon and the structural change of MWCNT. As a result, the Si-MWCNT nanocomposite was easily produced under separate injection conditions, and silicon nanoparticles of 20 nm or less were attached to the surface of the MWCNT. We evaluated the electrochemical performance of the synthesized material by assembling a CR2032-type coin cell using it as an anode electrode material.