Radial shells (1-voxel thick layers) were defined using a distance transform from the particle surface inward. The central 50% of these shells represents the region where electrochemically induced cracking typically occurs (see Figure in the SI for analysis nomenclature). Analysis of mean pixel intensity shows that cracks start forming at voltages as low as 4.0 V (vs Li/Li + ), indicated by a decrease in mean intensity. This worsening continues at 4.1 V and 4.2 V but does not progress further up to 4.4 V. While one might expect cracking to increase with voltage as primary particles shrink, we find that raising the voltage above 4.2 V does not significantly impact mean radial pixel intensity during the first charge. This is curious, as cycling to voltages above 4.2 V is known to result in rapid capacity loss. It implies that cracking alone may not be the primary cause of capacity degradation at these voltages. Instead, electrochemical reactions on the newly-exposed surface, driven more strongly by higher potential, likely contribute more significantly to capacity loss. Similar observations have been made in ex-situ studies of NMC cathodes and imply that other mechanisms, such as oxygen loss, transition metal dissolution and electrolyte oxidation, may drive capacity loss when the cell is charged beyond typical operating voltages, especially at voltages approaching 5.0 V. 4 Cracking has long been linked with crystallographic activity and, more importantly, to the non-homogenous volume changes in primary particles, causing them to move and separate from each other in an anisotropic way. This phenomenon is commonly observed in the c-lattice, where progressive delithiation leads to a moderate expansion of the interlayer distance until about 4.15 V vs Li/Li + . Beyond this voltage, the c-lattice parameter rapidly decreases, causing a reduction in interlayer spacing, often called c-lattice collapse. This coincides with the voltage where we initially see the most damage across the particles. At this moderate state of overall delithiation, it is possible that there exists a multiplicity of states of delithiation within different primary particles of the secondary agglomerates, possibly in a core-shell manner, which would lead to stresses from the secondary-particle level heterogeneities. Heterogenous lithiation has been suggested to be a contributor of higher micro-cracking within secondary particles previously, and may be a factor promoting nonlinear damage behaviour here. According to Shishvan et al., even at high lithium homogeneity, significant particle strain arises due to a 'mismatch between the primary particles combined with the highly anisotropic elastic and lithiation properties,' leading to a substantial strain field being induced in the secondary particle during the first charge process. It is also possible that dislocations within the primary particle domain may contribute to mechanical instability to induce intergranular cracking on the micro scale. During discharge, we observe a non-linear damage pattern with increasing lithiation. Particles worsen at 4.2 V DC but show recovery as lithiation continues (see Figure ). A slight increase in damage is seen when discharging from 4.0 V to 3.8 V, indicated by lower radial pixel intensity at 3.8 V, but particles recover by 2.5 V DC, with mean pixel intensity approaching pristine levels. This suggests a reduction in voids, defects, or cracks, though small cracks may remain. Our analysis shows that primary particles within the secondary agglomerate move closer together at the end of discharge, reversing the separation seen during charging. However, we do not expect the primary particle boundaries to fully reform to the pristine state, which would require conditions such as sintering.