Since SAM is an operando technique, we are able to simultaneously perform EIS measurements on the cell. Figure shows the high frequency resistance extracted from EIS, a value that is shown to be inversely correlated to the degree of electrolyte wetting, as well as the averaged amplitude across the cell area. These values are very well correlated, indicating that ultrasonic amplitude changes are indeed reflective of electrolyte wetting, and that the bulk of the wetting occurs within the first 12 hours. We further note that the amplitude continues to change for several hours after the EIS high frequency resistance has reached a steady state, indicating that further chemo-mechanical changes are occurring within the cell that are not captured by the EIS measurement. Further investigation of this effect will be performed in a later study.