Scalable Synthesis and Electrochemical Properties of Porous Si-CoSi2-C Composites as an Anode for Li-ion Batteries

Abstract

Si-based anodes for Li-ion batteries (LIBs) are considered to be an attractive alternative to graphite due to their higher capacity, but they have low electrical conductivity and degrade mechanically during cycling. In the current study, we report on a mass-producible porous Si-CoSi2-C composite as a high-capacity anode material for LIBs. The composite was synthesized with two-step milling followed by a simple chemical etching process. The material conversion and porous structure were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and electron microscopy. The electrochemical test results demonstrated that the Si-CoSi2-C composite electrode exhibits greatly improved cycle and rate performance compared with conventional Si-C composite electrodes. These results can be ascribed to the role of CoSi2 and inside pores. The CoSi2 synthesized in situ during high-energy mechanical milling can be well attached to the Si; its conductive phase can increase electrical connection with the carbon matrix and the Cu current collectors; and it can accommodate Si volume changes during cycling. The proposed synthesis strategy can provide a facile and cost-effective method to produce Si-based materials for commercial LIB anodes.

Impact of Full Prelithiation of Si-Based Anodes on the Rate and Cycle Performance of Li-Ion Capacitors

“…Si has attracted considerable attention as an LIC anode active material because of its very high specific capacity with regard to Li-ion insertion/extraction (3580 mAh/g at room temperature, 10 times higher than that of graphite) [19][20][21]. The use of Si has the advantage of increasing the energy density of assembled LIC cells, thus enabling cell miniaturization.…”

Si-based Anode Lithium-Ion Batteries: A Comprehensive Review of Recent Progress

“…Meanwhile, being electrochemically inactive or less active toward Li + , Co provides structural stability to Si-based materials. 105 For instance, Liu et al 30 utilized the ball milling method to anchor a Polyoxometalate-based complex on layered graphene oxide (GO), resulting in the generation of an amorphous Co-SiW phase with increased GO content (as shown in Figure 11B). This amorphous portion effectively facilitated the migration of Li + during the preparation of the Co-SiW-GO composites.…”

“…This material consists of a combination of graphite and well-dispersed nanocrystalline Si (active for Li) and FeSi 2 (inactive for Li) in an amorphous carbon matrix. Meanwhile, being electrochemically inactive or less active toward Li + , Co provides structural stability to Si-based materials . For instance, Liu et al utilized the ball milling method to anchor a Polyoxometalate-based complex on layered graphene oxide (GO), resulting in the generation of an amorphous Co-SiW phase with increased GO content (as shown in Figure B).…”