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

Abstract

SiOx is a silicon-based anode material for Li-ion batteries that has a high specific capacity and good cycle life. Lithiation of SiOx results in the formation of active Si cores surrounded by an inactive stabilizing matrix of irreversible lithium silicates and lithium oxides. SiOx 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 SiOx as the roller milling process proceeded. A simple 4-step procedure to determine the oxygen content in SiOx 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.

Simple Synthesis and Characterization of Ball Milled SiOx for Use as a Negative Electrode Material

“…Oxygen content can be tracked using the KOH method as the milling process proceeds, 22 as shown in Figs. 4a and 4b.…”

“…Oxygen content was determined using a KOH pouch bag technique that quantifies the volume of gas produced in the reaction between a KOH-water solution and a precise amount of SiO x powder. 22 Electrode slurries were prepared by combining active material, conducting carbon and single wall carbon nanotubes with a 25 wt% aqueous solution of Lithium Polyacrylate (LiPAA) and distilled water. The carbon nanotubes are added in small quantities to make up 0.1%, 0.2%, and 0.4% of the final dry mass composition.…”