Despite significant progress in the field of tomography, capturing the carbon binder domain (CBD) morphology presented in the Li‐ion electrode remains challenging, due to its low attenuation coefficient. In this work, quantitative phase contrast X‐ray nano‐holotomography is used as a straightforward approach that provides a large reconstructed volume, where the CBD can be resolved along with the active materials and the pore space. As a result, a complete quantitative analysis of the microstructures of three LiNi0.5Mn0.3Co0.2O2 high energy density electrodes, including the characterization of each phase separately along with the statistical quantification of their inter‐connectivity at particle scale, is performed. The microstructural heterogeneities are quantified and comparison between different electrodes is done. The results from this work suggest reasons for the negative impacts of the CBD excess on the electrode performance at high C‐rates. Those results are true in the case of high energy density electrodes, and are due to the reduction of the electrochemical active surface area. This sheds light on the optimization of the electrode design to improve the power rate of high energy density electrodes.

We investigated the lithium peroxide (Li 2 O 2 ) and pore size distribution in lithium−O 2 battery electrodes at different states of charge using transmission X-ray microscopy coupled with Zernike phase contrast to carry out nanocomputed tomography. We report that such a technique enables us, at the nanoscale, to distinguish light elements such as carbon and Li 2 O 2 in Li− O 2 battery cathode electrodes. We verified by wave-propagation simulation that this approach efficiently improves the contrast of images in comparison with pure absorption. The Li 2 O 2 distribution and thickness, interphases, and pore network are visualized and quantified, giving a valuable insight into our cathode architecture. From this 3D analysis, we highlight modifications of the air-cathode morphology and the Li 2 O 2 spatial organization as well as their potential implication in terms of carbon surface passivation and pore-clogging. After the full recharge process, this technique can also reveal the spatial distribution of the residual Li 2 O 2 and other byproducts.