Silica-Derived Hydrophobic Colloidal Nano-Si for Lithium-Ion Batteries

Abstract

Silica can be converted to silicon by magnesium reduction. Here, this classical reaction is renovated for more efficient preparation of silicon nanoparticles (nano-Si). By reducing the particle size of the starting materials, the reaction can be completed within 10 min by mechanical milling at ambient temperature. The obtained nano-Si with high surface reactivity are directly reacted with 1-pentanol to form an alkoxyl-functionalized hydrophobic colloid, which significantly simplifies the separation process and minimizes the loss of small Si particles. Nano-Si in 5 g scale can be obtained in one single batch with laboratory scale setups with very high yield of 89%. Utilizing the excellent dispersion in ethanol of the alkoxyl-functionalized nano-Si, surface carbon coating can be readily achieved by using ethanol soluble oligomeric phenolic resin as the precursor. The nano-Si after carbon coating exhibit excellent lithium storage performance comparable to the state of the art Si-based anode materials, featured for the high reversible capacity of 1756 mAh·g after 500 cycles at a current density of 2.1 A·g. The preparation approach will effectively promote the development of nano-Si-based anode materials for lithium-ion batteries.

Preparation of a Si/SiO2–Ordered‐Mesoporous‐Carbon Nanocomposite as an Anode for High‐Performance Lithium‐Ion and Sodium‐Ion Batteries

“…Another peak at 0.25 V is related to the alloy reaction between Li ions and Si to form Li–Si alloy. Furthermore, two clear oxidation peaks located at 0.29/0.48 V are associated with the de‐lithiation of Li–Si alloy . In addition, the discharge–charge profiles of the Si/SiO 2 –OMC electrode at 0.2 A g −1 with the voltage window of 0.01–3 V are also displayed.…”

Silicon Anodes for High‐Performance Storage Devices: Structural Design, Material Compounding, Advances in Electrolytes and Binders

“…After carbonization, a uniform layer of carbon is applied to the outside of the silicon particles. It has achieved the high and stable reversible capacity of 1756 mAh g −1 after 500 cycles at a current density of 2.1 A g −1 , and specific capacity of nearly 1000 mA h g −1 at C/3 after 200 cycles with a coulombic efficiency of >99.6% . As shown in Figure , Si@C@void@C using PS as the precursor generating pores and inner C shells and PAni as the source for exterior C shells showing a reversible capacity of approximately 630 mAh g −1 at 1000 mA g −1 .…”

“…The design and preparation that from 0D to 2D nano‐silicon anode has largely solved this problem. In order to obtain nanoscale silicon particles, generally, a grinding assisted alkaline etching or a mechanical milling method directly at room temperature may be employed . In addition, silicon nanoparticles prepared to use high energy ball milling techniques also exhibit excellent electrochemical performance .…”

Necklace-like Si@C nanofibers as robust anode materials for high performance lithium ion batteries

“…Lithium ion batteries (LIBs) with high energy density have drawn much attentions due to the ever-growing demand for technological applications, such as electric vehicles, portable electronics and renewable power stations [1][2][3][4][5]. The energy density of LIBs can be improved by using electrode materials with high theoretical capacities and proper working potentials [6][7][8].…”