Yiyang Li1
University of Michigan1
Heterogeneity is a commonly observed in battery materials at a variety of length scales. While heterogeneity at the electrode or cell level can be studied and understood based on porous electrode transport losses, the intrinsic heterogeneity and variability in electrochemical properties between individual particles is much more challenging to unravel. Most research into particle-level variability utilize microscopy, but this approach is only able to indirectly measure the electorochemistry using a spectroscopic signature. In this work, we present our research utilizing single-particle electrochemistry to directly quantify the electrochemical properties of single particles. By electrochemically cycling many commercial polycrystalline NMC battery particles under nominally identical conditions, we show that the area-specific resistance vary by as much as 5 times within a batch of commercial battery particles. We combine these experimental results with a porous electrode model to show how the electrochemical variability between individual particles ultimately affects the overall macroscopic behavior of the battery electrode.