The goal with this application is to explain experimental electrochemical impedance spectroscopy measurements （EIS; see the section Background—Electrochemical Impedance Spectroscopy （EIS）） and to show how you can use the model and the measurements to estimate the properties of lithium-ion batteries. The application takes experimental data from EIS measurements as input， simulates these measurements， and then runs a parameter estimation based on the experimental data. The control parameters are the exchange current density， the resistivity of the resistive layer on the particles， the double-layer capacitance of NCA， the double-layer capacitance of the carbon support in the positive electrode， and the diffusivity of the lithium ion in the positive electrode. The fitting is done to the measured impedance of the positive electrode at frequencies ranging from 10 mHz to 1 kHz. The figure below shows the application’s user interface （UI）。 To use it， do as follows： 1 Upload a comma-separated values （.csv） file and plot this data in the UI. 2 Define the model input and select the parameters to estimate. 3 Click the Run Parameter Estimation button to solve the model equations. 4 Generate a report from the parameter study