High-performance silicon from quartz product waste as an anode material for Li-ion batteries

Abstract

As the demand for quartz products increases year over year, the increase in the production of quartz waste has gradually contributed to increases in resource waste and environmental pollution. To recover quartz from spent quartz product waste and realize its high-value utilization, quartz waste ($0.15/kg) was used as the raw material to prepare high-performance porous silicon as an anode material for lithium ion batteries via a simple high-energy ball-milling method, followed by magnesiothermic reduction. The formation mechanism of silicon from quartz particles with different particle sizes during magnesiothermic reduction was investigated by X-ray diffraction, field-emission scanning electron microscopy, and other methods. The preparation of porous silicon without residual impurities was determined to be highly dependent on the size of the quartz particles after high-energy ball milling. When formed into an anode material for electrochemical measurements, the pure porous silicon (Si-4) anode delivered an initial specific charge capacity of 2712 mAh·g−1 with a high initial Coulombic efficiency of 81% at a current density of 200 mA g−1. The specific capacity was sustained at 923 mAh·g−1 for 300 cycles at a current density of 4000 mA g−1. The results reported herein highlight the feasibility of recovering spent quartz resources for harmless treatment and high-value utilization.