Facile Preparation of the Silicon/Carbon Composite Anodes from Photovoltaic Industry Waste for Lithium-Ion Batteries

Abstract

Silicon is identified as the most promising anode candidate for next-generation lithium-ion batteries (LIBs). However, its application is limited by the large volume variation and high cost. In this study, the silicon powders from the kerf slurry wastes are used as raw materials for the preparation of silicon/carbon composite anodes for lithium-ion batteries. An effective pretreatment process that combines the sand milling and a chemical cleaning method is utilized to prepare the purified silicon powders. Then, a facile one-step hydrothermal method is used to prepare the purified silicon/carbon composites. The results demonstrate that the chemical purification can effectively remove the organic contaminants and metal impurities on the surface of raw silicon powders. It also renders hydrophilic surfaces for the silicon powders, which improves the bonding of carbon layer and results in the improvement of the electrical performance correspondingly. The as-prepared purified silicon/carbon anode shows a high specific discharge capacity of 2099 mAh g-1 in the first cycle at the current density of 0.2 A g-1. The capacity still maintains a value of 1010 mAh g-1 after 148 cycles at the current density of 0.5 A g-1. This work not only provides a reasonable and facile solution for recycling silicon wastes from the kerf slurry but also provides a strategy for the preparation of advanced anodes for high-performance lithium-ion batteries.

Keywords: Photovoltaic industry waste, Si anode, Recycling, Chemical purification, Lithium-ion batteries