SiO_x as a Potential Anode Material for Li-Ion Batteries: Role of Carbon Coating, Doping, and Structural Modifications

Abstract

Despite the high energy density of SiO x , its practical use as an anode material for Li-ion batteries is hindered by its low electronic conductivity and sluggish electron transport kinetics. These disadvantageous properties result from the insulating nature of SiO 2 , which leads to electrical contact loss and poor cyclability. Herein, we synthesized a C-SiO x composite based on amorphous carbon and a SiO x matrix via the alcoholysis reaction between SiCl 4 and ethylene glycol. We then used nonpolar benzene to simultaneously achieve homogenous dispersion of the Si source and the formation of a carbon coating layer, resulting in the formation of a (C-SiO x)@C composite with exceptional electrochemical properties. Next, we performed structural modifications using Ti doping and a multiple-carbon matrix to successfully fabricate a (C-Ti x Si 1− xO y)@C composite. The combination of Ti doping and carbon coating greatly enhanced the conductivity of SiO x ; moreover, the incorporated carbon acted as an effective oxide buffer, preventing structural degradation. The (C-T i x Si 1− xO y)@C composite exhibited excellent capacity retention of 88.9% over 600 cycles at 1 A g −1 with a capacity of 828 mAh g −1 .

Surface Oxidation of Nano-Silicon as a Method for Cycle Life Enhancement of Li-ion Active Materials

“…The poor initial cycle efficiency is a common problem observed for SiO x -based electrodes. Nevertheless, the efficiency value recorded for the Si-2 sample is higher compared to the reported in the literature for SiO x -based electrodes (30–48%) [ 43 , 44 ]. Furthermore the Si-2 material maintains a similar or higher specific capacity and capacity retention [ 43 , 44 ].…”

“…Nevertheless, the efficiency value recorded for the Si-2 sample is higher compared to the reported in the literature for SiO x -based electrodes (30–48%) [ 43 , 44 ]. Furthermore the Si-2 material maintains a similar or higher specific capacity and capacity retention [ 43 , 44 ]. After the initial cycle, the efficiency quickly increases and stabilizes at 99.3% indicating very good electrode structure and SEI stability.…”

Boosting Cyclability and Rate Capability of SiOx via Dopamine Polymerization-Assisted Hybrid Graphene Coating for Advanced Lithium-Ion Batteries

“…As shown in Figure 3g, the SiO x particles appears to be buried in the side products consisting of the F-containing compounds, indicating that the SiO x particles have been broken and side reactions probably occurs during cycling. 29 As for the SiO x @ PDA@GNH anode, as shown in Figure 3h, the SiO x particles are no longer wrapped by the thick side products. In addition, wellproportioned N can be observed of the coated particles, which indicates that the coating layer is stable during the whole cycling (Figure S6).…”

“…The element distribution was characterized with TEM mapping for powder scraped from the tested anodes (Figures g,h and S5). As shown in Figure g, the SiO x particles appears to be buried in the side products consisting of the F-containing compounds, indicating that the SiO x particles have been broken and side reactions probably occurs during cycling . As for the SiO x @PDA@GNH anode, as shown in Figure h, the SiO x particles are no longer wrapped by the thick side products.…”

Synthesis of Silicon Oxycarbide Beads from Alkoxysilane as Anode Materials for Lithium-Ion Batteries

“…8 There are a few ways to synthesize SiOCs. For example, Yang et al 9,10 mixed silicon tetrachloride and ethylene glycol to synthesize SiOCs and further added benzene to increase silicon homogeneity and carbon content. However, SiOCs synthesized by this method were irregular in shape; ball milling was required to get a suitable particle size for anode applications.…”