Growth of silicon/carbon microrods on graphite microspheres as improved anodes for lithium-ion batteries

Abstract

We report a facile chemical vapor deposition (CVD) method to grow silicon/carbon (Si/C) microrods on the surface of commercial graphite microspheres (GMs) to prepare Si/C/GM composite materials as Li-ion battery anodes. Dimethyldichlorosilane and toluene were used as Si and C precursors, respectively. The CVD temperature and time, as well as the mechanism of materials growth were investigated. The samples were characterized by using X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy.It was found that the obtained Si/C/GM composites with an urchin-like morphology are composed of Si particles, amorphous carbon, and graphite. The CVD conditions have a significant impact on the morphology and electrochemical performance of the composite materials. The composite prepared under the optimum CVD conditions, namely at 900 C for 5 h, displayed the best anode properties with a specific capacity of 562.0 mA h g À1 at a current density of 50 mA g À1 , much higher than that of GMs (361.0 mA h g À1 ), and a good cycling performance (i.e., a reversible capacity of 590.5 mA h g À1 after 50 cycles). The improved electrochemical performance is attributed to the incorporation of Si, together with the formation of a Si/C microrod network, which connects the GMs and buffers the volume change of Si during lithium ion insertion/extraction. The work provides a simple and low-cost route to enhance the performance of commercial graphite anode materials for Li-ion batteries.

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

“…The strong peaks at around 500 cm −1 for all the samples are ascribed to Si and SiO. [ 32,33 ] The weak peak at about 1350 cm −1 (D-band) is associated with the amorphous carbon materials, [ 34 ] while the strong peak at around 1590.0 cm −1 (G-band) is attributed to the vibration of sp 2 -bonded carbon atoms in a 2D hexagonal lattice, [ 35 ] namely the stretching modes of C C bonds in typical graphite. The low-intensity and weak G-band peak suggests a structural imperfection of the graphene sheets such as defects and small crystal domain size, [36][37][38] implying these samples have low graphitization degrees.…”

“…The components of 30, 40 and 50@Si-granadillas were further confi rmed by X-ray photoelectron spectra (XPS) spectrum in Figure 4 c. The peaks located at 101.1 eV can be assigned to Si 2p, indicating the presence of a layer of silicon oxide species on the surface of all the samples. [ 32 ] Strong peaks at 285.2 eV are ascribed to the C 1s. [ 32 ] slight weight increase after 700 °C, which means the oxidation of silicon under high temperature.…”

“…[ 32 ] Strong peaks at 285.2 eV are ascribed to the C 1s. [ 32 ] slight weight increase after 700 °C, which means the oxidation of silicon under high temperature. Figure 5 a shows the fi rst, second, and fi ftieth charge and discharge curves of 50@Si-granadillas at a current density of 250 mA g −1 .…”

Catalyst Ni-assisted synthesis of interweaved SiO/G/CNTs&CNFs composite as anode material for lithium-ion batteries

“…and the method of adopting various buffer matrixes (Si/C composites etc.) have been researched to suppress the volume change and improve the electrochemical performance [15][16][17][18][19][20]. Though the electrochemical performance is significantly improved, their preparation technologies trend to be complicated, costly and difficult for industrial production.…”

One-step synthesis of a silicon/hematite@carbon hybrid nanosheet/silicon sandwich-like composite as an anode material for Li-ion batteries

“…For all the silicon-based samples, the strong peaks at about 500 cm -1 , are ascribed to Si and SiO. [36][37] The peak at around 1350 cm -1 (D-band) are associated with the vibration of carbon atoms with dangling bonds in plane terminations of the AC, 38 while the strong peak at about 1590.0 cm -1 (G-band) can be assigned to the vibration of sp 2 -bonded carbon atoms in a two-dimensional hexagonal lattice, 39 namely the stretching modes of C=C bonds in typical graphite. For the carbon-based samples, a low-intensity and weak G-band peak suggest a structural imperfection of the graphene sheets such as small crystal domain size or defects.…”