Comparisons of representative slices of the particles at 8400 eV are shown in Figure , extracted after tomographic reconstruction. The thickness of each data slice that made up the total TXM volume is equal to the ~0.049-micron pixel spacing, removing projection effects in the raw 2D image as collected. Thus, these thin slices provide enhanced quality of visualization of particle morphology and internal porosity compared to cross-section SEM. The differential absorption of the K-edge energy pairs produced maps of elemental intensity (colored maps in Figure ). Average elemental percentages for each particle were calculated based on the total Ni, Mn, and Co intensity values collected over their entire volume (Figure ). These values were in high agreement with previous elemental analysis, which verifies the elemental specificity of the differential absorption technique. There was a greater deviation between average differential absorption percentages and reported values for the 86%Ni sample, ~5% vs. ~2% or less in the other two samples. Limitations in the characterization of concentration gradients in a heterostructure arise from simplifying a three-dimensional object to a one-dimensional measurement through linescans of a single viewing plane.