Controlled fabrication of Si nanoparticles on graphene sheets for Li-ion batteries

Abstract

A new route is presented for the synthesis of Si nanoparticle/Graphene (Si-Gr) composite by a sonochemical method and then magnesiothermic reduction process. During the process, silica particles were firstly synthesized and deposited on the surface of graphene oxide (SiO2-GO) by ultrasonic waves, subsequent lowtemperature magnesiothermic reduction transformed SiO 2 to Si nanoparticles in situ on graphene sheets. The phase of the obtained materials was influenced by the weight ratio of Mg to SiO 2-GO. With the optimized ratio of 1 : 1, we can get Si nanoparticles on Gr sheets, with the average particle size of Si around 30 nm. Accordingly, the resultant Si-Gr with 78 wt% Si inside delivered a reversible capacity of 1100 mA h g-1, with very little fading when the charge rates change from 100 mA g-1 to 2000 mA g-1 and then back to 100 mA g-1. Thus, this strategy offers an efficient method for the controlled synthesis of Si nanoparticles on Gr sheets with a high rate performance, attributing to combination of the nanosized Si particles and the graphene. 2013 The Royal Society of Chemistry. . Thus, this strategy offers an efficient method for the controlled synthesis of Si nanoparticles on Gr sheets with a high rate performance, attributing to combination of the nanosized Si particles and the graphene.

Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

“…When the capacity is restricted to 500 mAh/g, these composites operate reliably up to 90 cycles. 155,156 More complex nano Si architectures using carbon nanotubes, 157 graphene, 158,159 and other carbon or oxide supports 7,160,161 have also been developed and shown excellent capacity retention, but these have been synthesized only on the laboratory scale and further scale-up could be costly. In addition, the low areal loading along with the nano Si architectures results in low-volumetric energy density.…”

Free-standing composite hydrogel films for superior volumetric capacitance

“…We adopted graphene oxide (GO) in this study because it has shown great potential in the development of energy storage devices8,10,11,[30][31][32][33][34] and other applications7,9,35 . When GO suspension was mixed with the solution of PANi and poly (2-acrylamido-2methyl-1-propanesulfonic acid) (denoted PAMPA)groups of GO and the positively charged nitrogen atoms of both PANi and PAMPA (Figure S1acontains the polymers' morphology); leaving the mixture at 95 °C for 12 h changed the colour from brown to black.…”

Ultra-thick porous films of graphene-encapsulated silicon nanoparticles as flexible anodes for lithium ion batteries

“…The G-band is characteristic of graphitic sheets, corresponding to a well defined sp 2 carbon-type structure, whereas the D-band can be attributed to the presence of defects within the hexagonal graphitic structure. The intensity ratio of ID/IG is a parameter to evaluate the graphitization degree of the carbonaceous materials and the density of defects in graphene-based materials [35,36]. It can be seen that, after the thermal treatment, the ID/IG ratio decreases from 0.97 of the RGO film to 0.89 of the RGO/Si film, which can be attributed to a significant increase of the in-plane sp 2 domain size.…”