Silicon Nanoparticle Ensembles for Lithium-Ion Batteries Elucidated by Small-Angle Neutron Scattering

Silicon in the form of nanoparticles has attracted significant interest in the field of lithium-ion batteries due to the enormous capability of lithium intake. In the present work we demonstrate the characterization of silicon nanoparticles using small-angle neutron scattering and complementary microscopy to elucidate the structure changes through the ball milling process with respect to the particle's functionality in lithium-ion batteries. Small-angle neutron scattering is a unique method for analysis of the nanoparticles as an ensemble, providing information which is often not accessible by the conventional methods for characterization of silicon nanoparticles such as microscopy. Herein we demonstrate that the analysis of neutron scattering allows to extract the specific surface area for silicon nanoparticles which was found to correlate with the first cycle Coulombic efficiency of the corresponding lithium-ion battery. In addition, using neutron scattering and electrochemical evaluation, we demonstrate that ball milling of silicon nanoparticles has different effects depending on the amorphous or crystalline nature of the material.