Composites of antimony metal, iron oxide, and carbon black are attractive for use as lithium ion battery anodes when high rate charging is required. The large capacity of such a composite, together with a voltage that is intermediate between lithium titanate and graphite, makes it possible to address the typical trade-off between high energy density and safe operation in high power conditions. In this work, a variety of mechanical homogenization processes are investigated. A minimum threshold of energy input per unit mass during milling is required to produce a sufficiently homogeneous microstructure, which is required for stable electrochemical performance. The surface area of the processed material is found to be a useful method for quantifying the degree of homogeneity in the composite and is well correlated to the electrochemical performance. This understanding enables simplified scaling on larger volume manufacturing assets.