Homogeneous Silicon Nanoparticle Formation by Plasma Flash Evaporation With the In‐Reactor Axial Cyclone and Its Quantification With Transfer Entropy

Well‐defined particle size distribution is an ultimate goal of nanoparticle production by plasma flash evaporation. To generate uniform Si nanoparticles, in the present work, we have attempted to homogenize the gas condensation paths by rectifying the plasma flow with an installation of axial flow cyclone in the plasma reactor. While coarse particles were removed by the cyclone effect, the nanoparticles produced are found to become finer and more uniform in particle size distribution. Computational fluid dynamics analysis has shown that the gas streamlines are uniformly ordered, and the gas temperature decreases monotonically in a shorter period by installing the cyclone. Transfer entropy was employed to evaluate quantitatively the degree of the homogenization of the gas condensation path, and it exhibited the increased similarity of the streamlines and reduction in half of its variation. These clearly suggest that the gas streamline rectification by the cyclone leads effectively to the uniform nanoparticle formation. The effect of the homogenized Si nanoparticles was evident as anode in a lithium‐ion battery: the battery initial capacity loss speed is reduced in nearly half, and the battery capacity retention is appreciably improved by the installation of the cyclones.