Preparation of high-rate anode materials based on porous highly conductive carbon coating and SiOx disproportionation reaction

Abstract

Silicon monoxide (SiO_x) has garnered considerable attention as an anode material owing to its high capacity. Nevertheless, its commercial viability is hampered by the low conductivity and inadequate cycling stability. In this study, a micrometer-scale silicon oxide/carbon composite (1000-SiOx/NC) was developed based on the porous and high electrical conductivity of pyrolyzed polydopamine (PDA) and the high-temperature disproportionation of SiO_x. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that the pyrolysis of polydopamine (PDA) not only improves electrode conductivity but also contributes to the formation of a stable solid electrolyte interface (SEI). Additionally, SiO_x undergoes disproportionation reactions during the pyrolysis of PDA, further the improves the cyclic stability of the composites. Consequently, the 1000-SiO_x/NC composite electrode exhibited an impressive specific capacity of 783.4 mAh·g⁻¹ after 500 cycles at 1 ​A ​g⁻¹, maintaining 80.1 ​% of its initial capacity. Additionally, at a high rate of 3 ​C, its capacity reached 607.3 mAh·g⁻¹ The synthesis approach is both straightforward and economical, offering a fresh avenue for the widespread commercial deployment of SiO_x.