Covalently Bonded Ball-Milled Silicon/CNT Nanocomposite as Lithium-Ion Battery Anode Material
Pierre Yosia Edward Koraag, Arief Muhammad Firdaus, Naufal Hanif Hawari, Andam Deatama Refino, Wibke Dempwolf, Ferry Iskandar, Erwin Peiner, Hutomo Suryo Wasisto, Afriyanti Sumboja
Abstract
The demand for high-capacity lithium-ion batteries (LIBs) is ever-increasing. Thus, research has been focused on developing silicon-based anodes due to their high theoretical capacity and natural abundance. However, silicon-based anodes still suffer from several drawbacks (e.g., a huge volume expansion during lithiation/delithiation and the low conductivity nature of silicon). In this study, we develop a facile and low-cost synthesis route to create a composite of silicon particles and carbon nanotubes (CNTs) via simple two-step mechanical ball milling with a silicon wafer as the silicon precursor. This method produces a strong interaction between silicon particles and the CNTs, forming Si–C bonds with minimum oxidation of silicon and pulverization of the CNTs. The resulting Si/CNT anode exhibits a first cycle Coulombic efficiency of 98.06%. It retains 71.28% of its first cycle capacity of 2470 mAh g−1 after 100 cycles of charge–discharge at a current density of 400 mA g−1. Furthermore, the Si/CNT anode also shows a good rate capability by retaining 80.15%, and 94.56% of its first cycle capacity at a current density of 1000 mA g−1 and when the current density is reduced back to 200 mA g−1, respectively.