Scalable synthesis of silicon nanosheets from sand as an anode for Li-ion batteries

Abstract

The silicon nanostructure is a promising candidate for an anode of Li-ion batteries due to its high theoretical capacity. In this work, we have demonstrated the scalable synthesis of Si nanosheets from natural sand by magnesiothermic reduction, and suggested a new formation mechanism for Si nanosheets. In the suggested mechanism, an Mg₂Si intermediate phase was formed at an early stage of the reduction process, which leads to the two-dimensional Si nanostructure. The synthesized Si nanosheets have a leaf-like sheet morphology ranging from several ten to several hundred nanometers, and show comparable electrochemical properties to the commercial Si nanopowder as an anode for lithium ion batteries. For the improved electrochemical performance, Si nanosheets are encapsulated with reduced graphene oxide (RGO), and the RGO-encapsulated Si nanosheet electrode exhibits high-reversible capacity and excellent rate capability.

All-in-one synthesis of mesoporous silicon nanosheets from natural clay and their applicability to hydrogen evolution

“…A more scalable way of synthesizing SiNSs is to combine the ball milling of commercial sands with a magnesiothermic reduction. 14 However, in spite of the simple nature of this process, the resulting SiNSs are almost all broken into small pieces and stacked in a large framework, limiting their use in various applications.…”

“…[11][12][13][14] For instance, Okamoto et al 11,12 demonstrated that organosilicon (Si 6 H 4 Ph 2 ) nanosheets can be fabricated by the chemical reaction of polysilane (Si 6 H 6 ) and a Grignard reagent. This method is useful for forming regularly stacked structures of SiNSs with limited dimensions.…”

Synthesis of Silicon Carbide Nanocrystals Using Waste Poly(vinyl butyral) Sheet

“…These peaks indicate that a low-temperature magnesiothermic reduction process reduces SiO 2 to Si perfectly, and reduced Si is combined with PC to form SiC. 12 In this study, the latter is the reason for the formation of Mg 2 Si due to the reaction with nanosized SiO 2 . Subsequently, acid treatment removed Mg compounds, the remaining main diffraction peaks were at 35.6°, 60.0°, and 71.8°, which emerged as single phase 3C-SiC (JCPDS card #29-1129).…”

Germanium coating boosts lithium uptake in Si nanotube battery anodes

“…However, Si NT electrode could not meet the demand on the high power density due to its poor rate capability attributed to inherently low electron conductivity and ion diffusivity. To improve these two parameters researchers have investigated in the last years different strategies such as the growth of Si on nanopillar metallic structrures [8], fabrication of core-shell composites [9], or coating of Si electrode with a good electron and/or ion conductor (polymer, graphene, etc) [10][11][12][13][14]. Very recently, Si/Ge double-layered nanotubes (Si/Ge DLNT) array prepared by employing a template-assisted synthesis method based on chemical vapor deposition process has been reported [15].…”