Lithiation Kinetics in Silicon/Mn3O4 Core–Shell Nanoparticles Anodes for Li-Ion Battery

Abstract

Silicon is predicted to become a significant component of high energy density Li-ion anodes. Mn-based cathodes for Li-ion batteries have been widely investigated in past years and Mn dissolution into the electrolyte, migration, and deposition on the anode’s solid electrolyte interphase present a major challenge. In this work, we intentionally synthesize manganese oxide with several nanoscale thicknesses on a Si nanomaterial and follow the electrochemical behavior of the core–shell nanoparticles as Li-ion anode. The structure of the nanocomposites is investigated using high-resolution scanning electron microscopy, high-resolution transition electron microscopy, X-ray diffraction, and electron paramagnetic resonance. The synthesis yields uniform nanoshells of Mn3O4 haussmanite phase. We demonstrate that the haussmanite phase is electrochemically active, and its presence improves the lithiation process during cycling. This study reveals that the formation of a thin shell of manganese oxide phase on Si anode can improve the lithiation kinetics of the Si nanomaterials, while a thicker shell slows down the kinetics. In summary, to a certain extent, the contamination of Si anode materials from Mn-based cathodic materials could have a positive impact on their electrochemical behavior.