Sodium-ion batteries (SIBs) are considered a more sustainable, resource saving, and cost-effective alternative to lithium-ion batteries (LIBs) as they can be designed without using critical or scarce raw materials and compounds such as cobalt, copper, lithium or graphite [1,2]. These advantages on the material level, along with the ability of using existing manufacturing equipment, have triggered the faster than expected commercialization of first SIB cells. The investigation of such cells is currently of huge interest within the scientific community. Initial studies by our group [3] and by others [4–7] show promising performance results. However, more data from such commercial SIB cells are necessary in order to understand their chemical composition, their cell design, and the interplay between both. Therefore, this study aims to characterize an early commercial 18650-type SIB cell with a nominal capacity of 1.5 Ah using a multi-scale approach from cell to material level. In order to assess the manufacturing quality of the cells and to gain information on the cell design, X-ray computed tomography (CT) and Post-Mortem analysis are performed on pristine cells. The electrochemical performance of full cells is evaluated in asymmetrical charge and discharge rate capability tests. Electrode characteristics are determined by physicochemical ex situ studies, including scanning electron microscopy (SEM, top view and cross-sectional
investigations) and mercury intrusion porosimetry measurements. The electrodes’ electrochemical properties are investigated in lab-scale half-cells through cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic cycling. On the material level, compositional and morphological information of the active materials are obtained via transmission electron microscopy (TEM) investigations coupled with energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). To complete the characterization, headspace gas chromatography-mass spectrometry (GC-MS) and differential scanning calorimetry (DSC) measurements are conducted on electrolyte and separator retrieved from the cells, respectively.
The results presented herein provide detailed valuable insights into the cell design and chemistry of this early commercial sodium-ion battery cell and enable a meaningful comparison with well-established lithium-ion cells.

References
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[3] K. Bischof, V. Marangon, M. Kasper, A. Aracil Regalado, M. Wohlfahrt-Mehrens, M. Hölzle, D. Bresser, T. Waldmann, Journal of Power Sources Advances 27 (2024) 100148. https://doi.org/10.1016/j.powera.2024.100148.
[4] M. Rehm, M. Fischer, M.R. Gomez, M.F. Schütte, D. Sauer, A. Jossen, Comparing the Electrical Performance of Commercial Sodium-Ion and Lithium-Iron-Phosphate Batteries, https://dx.doi.org/10.2139/ssrn.4937278.
[5] L. Streck, T. Roth, H. Bosch, C. Kirst, M. Rehm, P. Keil, A. Jossen, J. Electrochem. Soc. 171 (2024) 80531. https://doi.org/10.1149/1945-7111/ad6cfd.
[6] M. He, A.E. Mejdoubi, D. Chartouni, M. Morcrette, P. Troendle, R. Castiglioni, Journal of Power Sources 588 (2023) 233741. https://doi.org/10.1016/j.jpowsour.2023.233741.
[7] H. Laufen, S. Klick, H. Ditler, K.L. Quade, A. Mikitisin, A. Blömeke, M. Schütte, D. Wasylowski, M. Sonnet, L. Henrich, A. Schwedt, G. Stahl, F. Ringbeck, J. Mayer, D.U. Sauer, Cell Reports Physical Science 5 (2024) 101945. https://doi.org/10.1016/j.xcrp.2024.101945.