This dataset contains raw data from a multi-method characterization of a commercial 1.2 Ah 18650 sodium-ion battery cell. The data is assigned to the corresponding figures. The dataset includes: qOCV-fitting data, porosimetry data, Rietveld refinement and XRD data, electrical characterisation data of the cell under investigation, EIS-spectra, battery cycling results, GC-MS data from electrolyte extracted from the cell, results from float current measurements, and ultrasound measurement results. Further details can be found in the publication