Calendering can also be detected since it is a physical modification of the electrode density. This processes involves passing the electrode through rollers with a set gap to compress and compact the electrode to a specific thickness and consequently porosity. to 0.0106 g/cm 3 (n = 12231 for both, calculated from the black dashed boxes in Figure ) after calendering which suggests some inhomogeneity in mass (F test = 1.2191 > F crit = 1.0302). This may be indicative of densification of an initially highly porous region not achieving the same density after calendering compared to a region of lower initial porosity. This can be observed from the disappearance of speckles in the upper-right quadrant of the statistics area after calendering. The average acoustic density also increased by about 0.017 g/cm 3 , from 0.136 g/cm 3 uncalendered to 0.153 g/cm 3 calendered. The significant increase in acoustic density (t test = 131.4656 > t crit = 1.6450) † shows how ultrasound could be used to show the compaction of an electrode beyond the calendering roller gap. Further experiments and analysis may enable calibration or calculation of resulting electrode porosity from calendering.