Gas-Phase Synthesis of Silicon Nanoparticles and Mixing with Graphite Powders by Using Counter-Flow Injection

Abstract

Mixing between nano-sized silicon particles and micro-sized graphite powders was performed for anode materials of lithium ion batteries, in which the silicon nanoparticles were synthesized by silane pyrolysis under optimized conditions and were subsequently coated onto the surface of graphite powders at mixing chamber by counter-flow injection. The counter-flow injection was employed as a dry particle mixing process in order to generate uniform silicon-coated graphite powders. Furthermore, this method also made it possible to combine particle synthesis and mixing into one single operation. Energy dispersive X-ray spectroscopy (EDS) was utilized to examine the degree of mixing through surface chemical composition analysis of the mixture. Experimental results indicate that the jet Reynolds number can be considered as the key parameter to determine the homogeneity of the mixture and its critical value may be in the range of 120 to 180 for good mixing performance, being in reasonable agreement with previous studies.