KOH Based Method for the Determination of Oxygen Content in Ball Milled SiOx Material

SiO x is a silicon-based anode material for Li-ion batteries that has a high specific capacity and good cycle life. Lithiation of SiO x results in the formation of active Si cores surrounded by an inactive stabilizing matrix of irreversible lithium silicates and lithium oxides. SiO x with adjustable values of x can be synthesized by roller milling under oxygen flow, with the oxygen content being controlled by the amount of time spent milling in oxygen vs milling under argon. A fast and inexpensive oxygen content determination method was needed for determination of the oxygen content in SiO x as the roller milling process proceeded. A simple 4-step procedure to determine the oxygen content in SiO x is presented using a KOH solution, aluminized pouch bags, and Archimedes gas quantification measurements. This method can serve as a quick and inexpensive substitute to traditional oxygen content determination measurements such as gas fusion analysis.