Abstract
This study focus on the synthesis of amorphous silicon nanoparticles and understanding the formation mechanism. Counter-flow quenching gases with different flow rates were injected from downstream of the torch to understand the effect of quenching gas on the formation of silicon nanoparticles. Transmission electron microscopy show that nanoparticles with spherical shape and agglomerates consist of smaller particles were synthesized. X-ray diffraction analysis is used to calculate the amorphization degree, which is defined as fraction of amorphous silicon in the silicon nanoparticles including both crystal and amorphous. The obtained results show that higher quenching gas flow rate leads to smaller diameter with higher amorphization degree. Electron diffraction patterns reveal that nanoparticles with diameter less than 10 nm are amorphous and agglomerated together, while for the nanoparticles with diameter larger than 10 nm are crystal. The formation mechanism of amorphous silicon nanoparticles is explained by estimated nucleation temperature and experimental results. Consequently, silicon nucleates at about 2400 K and then silicon vapor condenses on the nucleus. Finally, smaller nanoparticles will keep amorphous phase, while nanoparticles with a larger diameter grow to form crystalline.
Highlights
In the last 20 years, lithium ion batteries (LIB) have been widely used in small electronic devices for their advantages in energy density and cyclic life
The amorphous silicon nanoparticle could be a good choice for the LIB anode
Several experiments were conducted with different quenching gas flow rates, in order to understand the effect of quenching gas on amorphous silicon nanoparticles synthesized with induction thermal plasma
Summary
In the last 20 years, lithium ion batteries (LIB) have been widely used in small electronic devices for their advantages in energy density and cyclic life. With the development of electric vehicles, higher requirements have been proposed on the performance of LIB, especially on their energy density. Carbon anodes have been proved very useful because of their stable cycling characteristics, but the small charge storage capacity limit the development of LIB. Researchers found the particle-size-dependent fracture behavior of silicon nanoparticle during the first lithiation; that is, there exists a critical particle size of ~150 nm below which cracking did not occur (Liu et al, 2012). Another approach to avoid the failure of the anode material is amorphization. The amorphous silicon nanoparticle could be a good choice for the LIB anode
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.