In this work, we investigate Tin (Sn) as a high capacity Li+ host material and perform an ex situ study with X-ray microtomography characterizing in three-dimensions (3D) Sn particle deformation during the crucial first cycles of lithiation/delithiation. We combine in-house algorithms with commercial software to develop 3D visualizations and measurements showing radial particle fracture, non-uniform lithiation of Sn particles, and a link between the global change in image intensity and loss of capacity. Particle size dependent "effective" volume expansion between 200% and 450% was measured during lithiation, and effective volume reductions of 50% were measured during delithiation. Relationships between the gray scale intensity change, volumetric expansion and particle size during the first cycle are also illustrated. (C) 2015 Elsevier B.V. All rights reserved.