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<p>A unique core–shell structured pitch-pyrolyzed carbon-coated porous Si/SiO<sub>x</sub>/needle coke (Si/SiO<sub><i>x</i></sub><b>/</b>NC@C) nanocomposite has been successfully synthesized via a low-temperature aluminothermic reduction combined with a scalable spray-drying and following carbonization processes. The fabrication of silicon-based materials in Si/SiO<sub><i>x</i></sub>/NC@C nanocomposites derived from high silica-containing silica fume powders enables effective utilization of industrial solid waste. The Si/SiO<sub><i>x</i></sub> nanoparticles in Si/SiO<sub><i>x</i></sub>/NC@C with abundant internal nanovoids are anchored on the surface of needle coke matrices, forming Si/SiO<sub><i>x</i></sub>-needle coke dual-phase cores, which are wrapped by a thin pitch-pyrolyzed amorphous carbon layer. The synergetic combination of these inherent advantages, such as high electroconductivity, porosity, amorphous/crystalline mixture structure, and high-valence SiO<sub><i>x</i></sub> residues, remarkably enhances the composite’s structural stability and buffers internal structure stress induced by alloying/dealloying of Si. The Si/SiO<sub><i>x</i></sub>/NC@C nanocomposites demonstrate exceptional electrochemical stability, exhibiting a specific reversible capacity of 771.5&#xa0;mAh&#xa0;g⁻<sup>1</sup> with minimal capacity decay (~ 0.06% per cycle) over 500 cyclic repetitions at an elevated current density of 200&#xa0;mA&#xa0;g⁻<sup>1</sup>. Rate capability tests show that the Si/SiO<sub><i>x</i></sub>/NC@C nanocomposites achieve a high capacity of 660.25&#xa0;mAh&#xa0;g<sup>−1</sup> even when subjected to the highest current of 3200&#xa0;mA&#xa0;g<sup>−1</sup>. More notably, this work provides a facile and promising economical route for the scalable industrial production of high-performance Si-needle coke anode materials for future LIBs from industrial solid waste.</p>

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Engineered pitch-pyrolyzed carbon-coated porous Si/SiOx/needle coke nanocomposites as anode material for enhanced lithium-storage performance

  • 期刊论文

  • 发表日期：

    2025年8月6日

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  • Bo Wang,
  • Yue Li,
  • Yan Lv,
  • Xuchao Wang,
  • JiaAi Gao,
  • Hui Wang

摘要

A unique core–shell structured pitch-pyrolyzed carbon-coated porous Si/SiOx/needle coke (Si/SiOx/NC@C) nanocomposite has been successfully synthesized via a low-temperature aluminothermic reduction combined with a scalable spray-drying and following carbonization processes. The fabrication of silicon-based materials in Si/SiOx/NC@C nanocomposites derived from high silica-containing silica fume powders enables effective utilization of industrial solid waste. The Si/SiOx nanoparticles in Si/SiOx/NC@C with abundant internal nanovoids are anchored on the surface of needle coke matrices, forming Si/SiOx-needle coke dual-phase cores, which are wrapped by a thin pitch-pyrolyzed amorphous carbon layer. The synergetic combination of these inherent advantages, such as high electroconductivity, porosity, amorphous/crystalline mixture structure, and high-valence SiOx residues, remarkably enhances the composite’s structural stability and buffers internal structure stress induced by alloying/dealloying of Si. The Si/SiOx/NC@C nanocomposites demonstrate exceptional electrochemical stability, exhibiting a specific reversible capacity of 771.5 mAh g⁻1 with minimal capacity decay (~ 0.06% per cycle) over 500 cyclic repetitions at an elevated current density of 200 mA g⁻1. Rate capability tests show that the Si/SiOx/NC@C nanocomposites achieve a high capacity of 660.25 mAh g−1 even when subjected to the highest current of 3200 mA g−1. More notably, this work provides a facile and promising economical route for the scalable industrial production of high-performance Si-needle coke anode materials for future LIBs from industrial solid waste.