A custom-made pouch cell holder made from Polyether Ether Ketone (PEEK) and an aluminium X-ray window was used to compress the pouch cell during the experiment. The holder allowed for repeated scanning of the same region of the electrode without removing the cell between tomographs. X-ray computed tomography was conducted at Diamond Light Source (DLS), Didcot, on the I13-2 Manchester Imaging beamline. Connections within the holder allowed for electrochemical control so the cell could be charged to specific voltages between 3.0-4.4V (vs. Li/Li + ), and images were acquired during open circuit voltage (OCV) after a voltage hold until the current had fallen to 10% of the charging current . A pco.edge 5.5 scintillator-coupled detector with pixel size of 6.5 x 6.5 μm was used in addition to a 10x objective lens giving an effective pixel size of 325 nm and FoV of 0.83 x 0.70 mm. 3000 projects were acquired for each tomography between 0-180 degrees at 0.8 seconds exposure. A pink beam at ~25 keV was used for each sample.