Waste-glass-derived silicon/CNTs composite with strong Si-C covalent bonding for advanced anode materials in lithium-ion batteries

Abstract Silicon is regarded to be promising anode materials in next-generation rechargeable lithium-ion batteries due to the high theoretical capacity and natural abundance. In order to overcome intrinsic drawbacks such as the low conductivity and unstable solid electrolyte interface film, different Si and carbon (C) nanocomposites have been designed but they are often plagued by the complex structural design, high preparation cost, and weak interactions between C and Si resulting in limited electrochemical performance. Herein, a facile, eco-friendly, low-cost, and controllable route is described to prepare Si/carbon nanotube composites with strong Si-C covalent bonding from recycled waste glass and commercial carbon nanotubes (g-Si/CNTs) via simple mechanical ball milling and magnesiothermic reduction (MR). Owing to the conductive CNTs network, strong Si-C covalent bonds are formed in situ between the CNTs and Si nanoparticles and consequently, the g-Si/CNTs electrode shows an excellent specific capacity of ~895 mAh g−1 as well as 84.3% capacity retention at 0.1 A g−1 after 200 cycles. The g-Si/CNTs composite produced from recycled waste glass has large potential as anode materials in high-energy lithium-ion batteries.