In situ SAXS/WAXS measurements were carried out on a custom-built two-electrode electrochemical in situ cell. The cell consisted of the positive AC electrode, a glass fiber separator (Whatman), a negative AC electrode and platinum foil current collector (CC). The assembly was sealed in a stainless-steel housing with an adhesive film (Tixo) X-ray windows. To enhance the recorded signal by increasing the amount of oxidized I -the negative electrode was oversized 8-times (mass = 32 mg, thickness = 600 µm, diameter = 12 mm) compared to the positive electrode (mass = 4 mg, thickness = 200 µm, diameter = 8 mm). Oversizing the negative electrode requires increasing its thickness rather than increasing the diameter to avoid detrimental, large ion diffusion pathways. To investigate only processes in the positive electrode, a hole with 2 mm diameter was cut into negative electrode, separator and CC. SAXS/WAXS data were recorded on an in-house SAXS facility using Cu-Kα radiation and a 2D areal detector (Dectris Eiger R 1M) with a nominal sample-to-detector distance of 100 mm. The primary 2D scattering data were azimuthally averaged and normalized by transmission values and recording time. Further, intensity data were multiplied by polarization 2 (1 + (cos 2 ) ) ⁄ and absorption 1 -!" #$ % & ln -% )* + ln & , correction factors to adequately normalize scattering intensities at large scattering angles 2 . The background scattering intensity was recorded after the in situ SAXS measurements and removing the WE; and subtracted from in situ SAXS/WAXS data after primary data treatment as described above.