Synthesis of nanosilicon@nonstoichiometric silicon oxide from bulk silicon dioxide and its lithium storage properties

Nanosilicon@nonstoichiometric silicon oxide where nanosilicon is embedded in SiOx matrix (abbreviated as nano-Si@SiOx), is a very attractive material structure to suppress the volume effect of silicon in Lithium-ion batteries. In this work, we demonstrate that the combination of electrolysis and peeling technique produce nano-Si@SiOx from bulk SiO2. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) are employed to characterize the prepared materials. The average O/Si atomic ratio of the synthesized nano-Si@SiOx is about 0.91. The nano-Si@SiOx/graphite composite prepared using it as the precursor exhibits a stable discharge capacity of about 1560 mAh g−1 (calculated on the total mass of the composite) with good cyclic stability and rate capability. This work provides a new routine to prepare nano-Si@SiOx composite.