Nanocomposite of Si/C Anode Material Prepared by Hybrid Process of High-Energy Mechanical Milling and Carbonization for Li-Ion Secondary Batteries

Abstract

Si/C nanocomposite was successfully prepared by a scalable approach through high-energy mechanical milling and carbonization process. The crystalline structure of the milled powders was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Morphology of the milled powders was investigated by Field-emission scanning electron microscopy (FE-SEM). The effects of milling time on crystalline size, crystal structure and microstructure, and the electrochemical properties of the nanocomposite powders were studied. The nanocomposite showed high reversible capacity of ~1658 mAh/g with an initial cycle coulombic efficiency of ~77.5%. The significant improvement in cyclability and the discharge capacity was mainly ascribed to the silicon particle size reduction and carbon layer formation over silicon for good electronic conductivity. As the prepared nanocomposite Si/C electrode exhibits remarkable electrochemical performance, it is potentially applied as a high capacity anode material in the lithium-ion secondary batteries.

Towards a High-Power Si@graphite Anode for Lithium Ion Batteries through a Wet Ball Milling Process

“…Their Si-coated graphite composite presented a first discharge capacity value of 761 mA h/g and the 78% of the capacity was retained at the 300th cycle. On the other hand, Maddipatla et al [50] presented a Si/C anode material, which was prepared following a high energy milling step to produce nanoscale Si particles, a carbonization step, and a final high energy milling step of the Si/C-coated powders. The composite delivered a remarkable capacity of 1181 mA h/g at the 100 th cycle.…”

“…The anode showed a capacity of 1178 mA h/g at 0.2 A/g and a capacity of 751 mA h/g at 1 A/g. Compared to other research studies [49][50][51]57], the Si@graphite material used in this case is synthesized in a single step that is easily-scalable, without further steps for reducing the size of the particles, since we used Si nanoparticles, nor for heating powder treatments. The reasons of the satisfactory performance of the rate capability test are: (i) suitable distribution of particles and intimate contact between them, (ii) the presence of small Si nanoparticles (<50 nm) in the anode implies shorter diffusion paths for Li ions, which means the current can be increased, and (iii) the use of FLG as a conductive additive in the anode formulation seems to play an important role reinforcing the anode microstructure due to its ability to buffer Si volume changes.…”

Electrochemical Performance of an Ultrathin Surface Oxide-Modulated Nano-Si Anode Confined in a Graphite Matrix for Highly Reversible Lithium-Ion Batteries

“…The Si powder obtained by 6 h milling (which was defined as nano-Si) was subsequently oxidized at different temperatures to form a SiO x layer over the nano-Si, and the corresponding XRD patterns are shown in Figure b. As shown in Figure b, the major peak intensities of Si situated at 2θ = 28.4 and 47.3° slightly increased with increasing oxidation temperatures, which indicates the recovery of Si crystallinity . XRD patterns of the Si/SiO x @C composite milled at different milling times are shown in Figure c.…”

“…Among them, reducing the silicon particle size to the nanoscale is one of the most viable strategies because of enhanced structural stability at the nanoscale. − Although, the nano-Si affords a promising opportunity to relax the stress/strain below critical sizes, the large volume changes still cause the isolation and separation of Si nanoparticles from the conducting media during long-term battery cycling . Other promising strategies are the dispersion of silicon in an active/inactive (or less active) matrix phase − and coating with carbon as well as using efficient binders and electrolyte systems. − In the above approaches, a variety of silicon nanocomposites with active and inactive materials have been widely used, in which the inactive (or less active) component plays an important role to mitigate the large volume changes of Si and to preserve the structural integrity of the electrode. − , …”

Effect of the Pillar Size on the Electrochemical Performance of Laser-Induced Silicon Micropillars as Anodes for Lithium-Ion Batteries

“…Ever since Sony Corporation first commercialized lithium-ion batteries (LIBs) in 1991, LIBs have played a critical role in enabling the emergence of electric vehicles (EVs) and the widespread availability of portable electronic devices such as laptops, smartphones, and video cameras [1][2][3][4][5][6][7]. However, graphite, as the anode material of traditional LIBs, has almost reached its performance limit for energy storage, and therefore increasing the specific capacity of the anode material remains a challenge [8][9][10][11][12][13][14].…”