Combined Neutron‐ and Synchrotron‐Based Diffraction Computed Tomography Studies of 18650‐Type Lithium‐Ion Cells

The distribution of lithium in nickel-cobalt-aluminium (NCA) cathodes and graphite anodes of cylindrical (18650) high-energy lithium-ion batteries was studied using a combination of neutron- and synchrotron-based diffraction computed tomography (DCT). The in-plane lithium concentration in the positive and negative electrodes was assessed in situ at various nominal states of charge and health. DCT is one of the few techniques that enable non-destructive examination of electrochemical storage systems such as batteries. Several DCT configurations were explored, with probe-beam sizes ranging from millimetres to a few micrometres, demonstrating the method's capability across different length scales. The use of thermal neutrons as a probe in DCT was demonstrated for structural studies of lithium-ion batteries, where the results were compared to similar studies using high-energy photons. In addition, a region-of-interest approach for X-ray DCT was successfully demonstrated for the non-destructive characterisation of electrochemical storage systems.