Amorphous silicon–carbon nanospheres synthesized by chemical vapor deposition using cheap methyltrichlorosilane as improved anode materials for Li-ion batteries

Abstract

We report the preparation and characterization of amorphous silicon-carbon (Si-C) nanospheres as anode materials in Li-ion batteries. These nanospheres were synthesized by a chemical vapor deposition at 900 °C using methyltrichlorosilane (CH3SiCl3) as both the Si and C precursor, which is a cheap byproduct in the organosilane industry. The samples were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption, thermal gravimetric analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. It was found that the synthesized Si-C nanospheres composed of amorphous C (about 60 wt%) and Si (about 40 wt%) had a diameter of 400-600 nm and a surface area of 43.8 m(2) g(-1). Their charge capacities were 483.6, 331.7, 298.6, 180.6, and 344.2 mA h g(-1) at 50, 200, 500, 1000, and 50 mA g(-1) after 50 cycles, higher than that of the commercial graphite anode. The Si-C amorphous structure could absorb a large volume change of Si during Li insertion and extraction reactions and hinder the cracking or crumbling of the electrode, thus resulting in the improved reversible capacity and cycling stability. The work opens a new way to fabricate low cost Si-C anode materials for Li-ion batteries.

Scalable Synthesis of Interconnected Porous Silicon/Carbon Composites by the Rochow Reaction as High‐Performance Anodes of Lithium Ion Batteries

“…The two peaks at about 515.2 and 965.5 cm −1 for all samples are characteristic of Si 9. The observation of a double maximum on a wide feature at 1350 cm −1 (known as the D band) and 1590 cm −1 (known as the G band) is characteristic of the presence of carbon materials in Si/C, Si/C‐900, and Si/C+C‐900 samples 3g. For Si/C‐900 and Si/C+C‐900 obtained by carbonization at 900 °C, the peaks of the G band and D band become stronger and the ratio of their intensities ( I G / I D ) increase from 0.51 for Si/C to 0.66 for Si/C‐900 and 0.68 for Si/C+C‐900, implying a high degree of graphitic content of the carbon layer after high‐temperature carbonization.…”

“…Many pioneering works have shown that the Si nanostructures with predefined void space and/or a conductive buffer layer can substantially accommodate the Si volume change preventing the fracture formation and improving their conductivity 3a. These nanostructures include Si nanowires,3b Si nanospheres,3c Si nanotubes,3d Si nanoparticles,3e porous Si,3f Si/C nanospheres,3g Si/C microwires grown on graphite microspheres,3h mixed Si nanopowder with alginate,1j Si nanoparticles embedded within carbon,3i Si‐coated carbon,3j graphene‐encapsulated Si,3k Ag‐coated Si,3l conductive polymer‐coated Si,3m and carbon‐coated Si 3n. All the above Si‐based anode materials have brought significant improvement to the electrochemical properties (capacity, cycle life, and rate performance) and understanding to the fundamental issues 1i.…”

Enhanced electrochemical performance of nanomilling Co2SnO4/C materials for lithium ion batteries

“…The discharge products presented a morphology with distributed cracking that has been found by others in lithium ion batteries. During the charge-discharge cycles, SEI forms and the volume change will cause slight cracking and particle pulverization, which are the reasons for the increase in the surface coarseness and fissures [32]. Microcracks in the CSO 30 electrode with a narrow width are lesser than those in the CSO 70 electrode, which is related to the high content of disordered carbon in CSO 30 .…”

Synthesis of porous microspheres composed of graphitized carbon@amorphous silicon/carbon layers as high performance anode materials for Li-ion batteries

“…47 For the SiO x PMs sample, the broaden XRD diffraction peak between 20 and 30 indicates the presence of SiO x aer calcination at 800 C in air. 44 The PSD curves (not shown here) reveals that the particle sizes of GCB PMs, GCB@Si/C-3 PMs, GCB@Si/C-6 PMs, and SiO x PMs is in the range of about 0.5-15 mm. Fig.…”