There is a wealth of knowledge related to degradation at the device level, which is most commonly characterised through cycling stability, but the phenomena that can contribute to capacity fade and/or cell failure are difficult to decouple experimentally due to their often multi-length scale nature (i.e. scale and resolution are almost always linked). For instance, cylindrical cells are known to exhibit heterogeneities in temperature and state of charge which can have a negative impact on the overall cell performance over prolonged periods of cycling . In addition, the manufacturing process of the various cell components can significantly affect the state of the active materials , introducing defects (e.g. particle cracking during calendering and active material layer delamination) responsible for reduced electrochemical capacity . Obtaining a chemical insight from within a real working device is therefore essential to achieve a thorough understanding of the evolving chemistry and possible aging mechanisms. Typically, battery materials are extracted from the device(s) and characterised by ex situ spectroscopy, scattering and microscopy-based techniques; the results are then compared against the initial state of active materials and subsequently the changes observed in the electrochemical performance data collected during the device operation (i.e. differential voltage analysis or electrochemical impedance measurements) are correlated to changes in the battery materials . Large cells can be also studied in a non-destructive manner using high energy X-rays and neutrons; techniques based on scattering and absorption have been proven to provide invaluable insight into the evolving solid-state chemistry and morphological/structural changes of cycled batteries (both in situ and ex situ) . More specifically, combining imaging/tomography with X-ray diffraction/scattering signal (e.g. X-ray diffraction computed tomography aka. XRD-CT) or neutron scattering (i.e. direct neutron imaging) allows for capturing the various chemical heterogeneities present across the battery cell which can be directly related to current heterogeneities . The order of magnitude higher spatial resolution achieved with XRD-CT images when compared to neutron diffraction imaging (e.g. 0.02 x 0.02 x 0.003 mm vs 2 x 2 x 20 mm respectively ) enables the visualisation of gradients in the distribution of lithiated graphite phases within one electrode as a function of cycling rate .