A variety of properties are used to characterize lithium-ion battery active materials when synthesizing a new material in the lab or controlling the quality in a manufacturing product line. Rate capability is one of these measured properties and is important because many applications need good high rate performance, for example plug-in hybrid electric vehicles. Rate capability tests are time and material intensive because they require electrode fabrication, cell fabrication, and cell cycling, and this entire process can take up to a couple of weeks. In addition, properties derived from coin cell cycling are not just dependent on the active material properties but also can be dependent on other electrode components and the electrode microstructure. In this talk, we will describe recent efforts to characterize suspensions of lithium-ion battery active materials. The electrochemical evaluation is relatively fast, under 30 minutes, and characterizes the active material particles in the electrolyte without the complicating factors of conductive additives, binders, and resulting electrode microstructures. The particles colliding with a current collector result in a single measured resistance, and in this talk we will demonstrate proof-of-concept that this resistance can correlate to the relative rate capability between active materials. Current limitations of the technique will also be described.