Efficient transformation of rice husk to a high-performance Si@SiO2@C anode material by a mechanical milling and molten salt coactivated magnesiothermic reduction

• Published in: Journal of alloys and compounds Vol. 875; p. 159974
• Main Authors: Zheng, Cui-Hong, Zhang, Gong-Ping, Wang, Shan-Shan, Mao, Ai-Qin, Fang, Dao-Lai
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.09.2021; Elsevier BV
• Subjects: Anodes; Current density; Electrochemical analysis; Electrochemical performance; Electrode materials; Lithium-ion batteries; Low temperature; Magnesiothermic reduction; Mechanical milling; Molten salt; Molten salts; Rechargeable batteries; Rice husk; Si@C based anode; Silicon dioxide; Rice husk; Electrochemical performance; Si@C based anode; Magnesiothermic reduction; Molten salt
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.159974

•A new avenue is opened for transformation of rice husk to Si@C-based anode materials.•A novel magnesiothermic reduction with higher reducing power is designed.•The anode material obtained shows an electrochemically favorable microstructure.•The anode material obtained shows superior electrochemical performance. A high-performance Si@SiO2@C anode material for Li-ion batteries was obtained by a novel synthetic strategy based on a mechanical milling and molten salt coactivated magnesiothermic reduction at a low temperature of 200 °C, only using rice husk as the Si and C sources. The anode material obtained presented an electrochemically favorable architecture, in which crystalline Si particles with a size of ~15 nm were uniformly embedded in the amorphous carbon and SiO2 matrix. The amount of the Si, SiO2 and C components in the anode material was determined to be about 17.2, 24.5 and 58.3 wt%, respectively. Electrochemical analyses demonstrated that the Si@SiO2@C anode material showed excellent electrochemical performance, delivering a reversible capacity of 1277.3 mAh g−1 at a current density of 0.1 A g−1, still possessing a high capacity of 910.2 mAh g−1 when increasing current density to 5 A g−1. After cycled for 200 cycles at 1.0 A g−1, the anode still preserved a reversible capacity of 973.1 mAh g−1, showing a capacity retention of 93.1% and a Coulumbic efficiency higher than 99.7%. Importantly, the synthetic strategy is not only more facile and cost effective, but also more environmentally friendly, compared with those recently reported. Thus it is promising to be applied for large-scale transformation of rice husk to high-performance Si@C-based anode materials for Li-ion batteries.