Zn-induced synthesis of porous SiOx materials as negative electrodes for Li secondary batteries

Abstract

Silicon oxide-based materials for Li-ion battery anodes have attracted extensive attention due to their higher capacity than graphite materials and better cycling performance compared to Si-based materials. However, the cycle performance needs to be further enhanced if they are to be widely used in commercial applications. In this study, we propose a simple strategy to prepare porous SiOx materials. Zn and SiO were combined by a high-energy mechanical milling process. The Zn/SiO composite was then heated to 900 degrees C and the Zn-based materials were removed by evaporation as Zn is a metal with a relatively low melting point (419.5 degrees C) and boiling point (907 degrees C). This process resulted in the production of porous SiO x materials with a large number of mesopores. Characterizations of the materials by X-ray diffraction analysis, X-ray photoelectron spectroscopy, and electron microscopy confirmed the synthesis of porous SiOx materials. The cycling performance of these materials was found to be improved. Carbon incorporation was performed in an effort to further enhance their performance, and the cycling performance of these porous SiOx/C composite materials was considerably enhanced, thus indicating that the strategy involving both a porous structure and carbon incorporation is very effective for improvement of the cycling stability of Li-alloy-based active materials. (C) 2019 Elsevier B.V. All rights reserved.