Synthesis and Characterization of SiOx by Mechanical Milling for Lithium-ion Battery Negative Electrodes

Abstract

The need for higher energy density Li-ion batteries has led to the investigation of higher energy density anode materials. Specifically, research is focused on transitioning away from intercalation materials in favor of silicon-based alloying electrodes. Silicon electrodes offer ten times the specific capacity of graphite at the cost of poor cycle life due to large volume expansions of 280% during lithiation. This poor cycle life is attempted to be improved with the introduction of SiOx. SiOx is composed of nano-regions of Si and SiO2 that provide a more stable microstructure to resist particle fracturing during cycling. The supporting matrix of lithium silicates also restrict the volume expansion of the material to 132% resulting in a more stable electrode structure. It is shown here that SiOx synthesized through mechanical milling is a suitable alternative to the current production method of vapor deposition. Mechanical milling is a well-known industrial process that would easily allow large scale production and integration into lithium-ion batteries.