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

Abstract

We report in situ growth of amorphous silicon/carbon (Si/C) layers on graphitized carbon black (GCB) particles in porous microspheres (PMs) for formation of novel GCB@Si/C PMs as high performance anode materials. The preparation included spray drying, KOH activation and chemical vapor deposition at 900 C, and used methyltrichlorosilane as both the Si and C precursor, which is a cheap byproduct in the organosilane industry. The obtained samples were characterized by X-ray diffraction, thermogravimetric analysis, nitrogen adsorption, transmission electron microscopy, and scanning electron microscopy. Compared with the bare GCB PMs, the GCB@Si/C PMs showed a significantly enhanced electrochemical performance with high lithium storage capacity and excellent cycling stability (the discharge capacity of GCB@Si/C-3 PMs and GCB@Si/C-6 PMs is maintained at 587.2 and 729.7 mA h g À1 after 200 cycles at a current density of 100 mA g À1 ), because the unique interconnected porous structure within the microspheres could absorb a large portion of Si volume change during Li insertion and extraction reactions, promote the diffusion of Li-ion and electrolyte solution, hinder the cracking or crumbling of the electrode, and additionally, the GCB and amorphous C provide high conductive electron pathway. This work opens a new way for fabrication of Si/C nanocomposites as anode materials for Li-ion batteries.

Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries

“…In a work by Shi et al [382], sacrificial spray-dried layered double oxide (LDO) microspheres act as a template and a catalyst for the CVD growth of graphene; chemical etching of LDO yields a 3D graphene host for sulfur in Li-S batteries. Zhang et al [383] reported CVD growth of a Si/C layer on graphitized spray-dried carbon black porous microspheres.…”

Integrating highly active graphite nanosheets into microspheres for enhanced lithium storage properties of silicon

“… 28 For example, Zhang et al proposed the direct growth of amorphous Si/C layers on graphitized carbon black particles distributed in microspheres by spray-drying method. 29 Peng et al prepared a dual-shell structure Si@SiO x @graphite/graphene (SGGr) by spray-drying. 30 It can be seen that graphite is common conductive agent for spray-drying induced synthesis of Si/carbon composites.…”

Amorphous Si/TiC/Graphite Composite Fabricated by High-Energy Ball-Milling as an Anode for Lithium-Ion Batteries

“…4,[7][8][9][10] Additionally, the resistivity of silicon is significantly higher than that of graphite, giving rise to the poor specific capacity of silicon anodes at high current density. 8,11 Therefore, to enable the application of silicon materials as high-performance lithium-ion battery anodes, it is necessary to reduce the volume expansion and resistivity of silicon anodes.…”