Mechanical Milling Synthesis and Electrochemical Evaluation of Silicon-transition Metal Alloy Anode Materials for Lithium-ion Batteries

Abstract

Silicon-alloys are candidates for anode materials of high capacity lithium-ion batteries. Here we report the mechanical milling (mechanical alloying) synthesis of various silicon-alloy samples. The samples have been characterized by X-ray diffraction, scanning electron and transmission electron microscopies, and electrochemical tests to investigate their electrochemical lithium insertion-extraction performance. The metallic elements added during alloying such as Ni, Co, Cu, and Zr are found to be effective for nanocrystallization or amorphization of silicon alloy. Especially Si-Sn-Cu alloy has high 1st lithium storage capacity of 2690 mAh g⁻¹ with a coulombic efficiency of 85% and relatively long cycle life. The changes of Si-Sn-Cu alloy composite electrode in volume and structure were also investigated to obtain insights for practical electrode design.