Scalable preparation of mesoporous Silicon@C/graphite hybrid as stable anodes for lithium-ion batteries

Abstract

A mesoporous Si@amorphous carbon/graphite (Si@C/G) material is synthesized by acid etching technique on a low-cost Al-Si alloy followed by ball-milling and heat treatment process. The Galvanostatic charge/discharge tests prove that the specific anodes hold a high gravimetric capacity of 919.0 mAh g−1 after 150 cycles. In addition, benefiting from the addition of the graphite, a relatively high initial coulombic efficiency of 78.4% is achieved. The physical-chemical properties are characterized by SEM, XRD, XPS, TEM and N2 sorption methods, revealing that the mesoporous Si is coated by amorphous carbon layer, ca. 20 nm. The mesoporous structure of Si can refrain the volume expansion of hybrid material during the lithium insertion/extraction process and can create efficient channels for the fast transport of Li+, and the outer carbon layer and graphite can increase the electroconductibility of the anode material. This low-cost Si@C/G hybrid material with improved electrochemical properties via a simple and applicable synthesis process on Al-Si alloy is prospective for scalable production in commercial lithium ion batteries.