Photovoltaic waste silicon powder-engaged construction of silicon/graphite nanosheet/carbon composite microspheres for lithium-ion batteries anodes

Abstract

Among potential anode materials for high energy density lithium-ion batteries (LIBs), silicon (Si) stands out as one of the most promising options. Nevertheless, the significant volume expansion (over 300 %) and unstable interface lead to a rapid decline in capacity, hindering the commercialization process of Si. In this study, Si-graphite nanosheet@carbon (Si-GN@C) microsphere anode has been prepared by employing spray drying and chemical vapor deposition using Si waste powder and GN. The synthesized Si-GN@C composite electrode demonstrates outstanding electrochemical performance, with an initial coulombic efficiency (ICE) of 91.2 %. It further displayed robust rate capability, maintaining 87.5 % capacity retention following several high-rate cycles. After cycling at a high current density of 1.0 A g⁻¹ , it maintains a reversible capacity of 616.6 mAh g⁻¹ over 300 cycles. In-situ impedance confirms that the Si-GN@C microsphere anode develops a stable and continuous solid electrolyte interface (SEI) layer during charge and discharge cycles. This study presents an effective approach to recover Si waste powder to produce excellent anode materials for LIBs.