Simple preparation of Si/CNTs/C composite derived from photovoltaic waste silicon powder as high-performance anode material for Li-ion batteries

Currently, with the rise of the photovoltaic industry, how to effectively treat waste silicon powder from an environmentally friendly and economic point of view becomes significant. We reported a simple method to prepare the core-shell structure of silicon/carbon nanotubes/carbon (Si/CNTs/C) composite by ball-milling using waste silicon powder. Specifically, The synergistic effect of CNTs and amorphous carbon matrix is beneficial to improving the transmission rate of Li-ions and electrons, and facilitating the reaction kinetics of Li-ions in the process of lithiation/de-lithiation. Meanwhile, the carbon coating layer reduces the direct contact between silicon and the electrolyte, which greatly alleviates the volume expansion of silicon in cycling. With these merits, Si/CNTs/C anode shows high rate performance and outstanding cycling stability up to 300 cycles at 0.2C. Furthermore, full cells assembled with prelithiated Si/CNTs/C anodes and commercial NCM811 cathodes deliver considerable initial coulombic efficiency (84.4%) and high energy density (502 Wh kg(-1)).

Automated summary

This article reports a simple method for preparing silicon/carbon nanotubes/carbon (Si/CNTs/C) composite with a core-shell structure by ball-milling waste silicon powder. The synergistic effect of CNTs and amorphous carbon matrix improves the transmission rate of Li-ions and electrons, facilitates the reaction kinetics of Li-ions, and reduces the volume expansion of silicon. The Si/CNTs/C anode exhibits high rate performance and outstanding cycling stability, with a significant initial coulombic efficiency and high energy density in full cells.