Lithium-ion cells EIS dataset with fitting and degradation modes

This Dataset includes data from eight LIB cells tested according to experimental protocols described in the associated article from Authors to which this dataset is linked.

Tested cells are Samsung INR18650-30Q with a nominal capacity of 2.95 Ah. Each cell has been aged up to 80% of his initial capacity and four different profiles have been tested. Parametric check-up, at fixed steps of 25 cycles, have been performed to collect capacity fade and EIS measurement data.

ExperimentalDATA Folder: Inside this folder, there are eight .xlsx files, named according to the convention “EISexpCellxx.xlsx”, meaning EIS data experimental for the cell “xx”. Eight cells have been tested therefore there are eight files, each containing ten columns as descripted below.

• Aging cycle prior to the impedance spectroscopy measurement.
• SOH (%): Calculated after the aging cycles according to the manufacturer’s protocol.
• SOC (%): Indicates the cell’s charge level, expressed as a percentage of its current capacity, at the time the spectroscopy was performed.
• R_int (%): The percentage increase in internal resistance compared to a fresh cell, calculated using Ohm’s law (ΔV/I). This value is obtained for each SOC level after a controlled discharge test. The voltage variation (ΔV) is calculated as the difference between the OCV value at the reference SOC and the voltage measured 5 seconds after the application of the constant current.
• Frequency (Hz): Frequency points used for the impedance spectroscopy measurements.
• Zmod (Ohm): The module of the impedance calculated at each frequency during the spectroscopy.
• Zphz (deg): The phase of the impedance calculated at each frequency during the spectroscopy.
• Zreal (Ohm): Real component of the complex impedance.
• Zimg (Ohm): Imaginary component of the complex impedance.
• OCV (V): The voltage measured at open circuit for each SOC level, after a 45-minute relaxation period.

OutputDATA Folder: It contains eight subfolders, each corresponding to one of the tested cells for which experimental data was provided. Inside each subfolder there are two .xlsx files named “Circuit_parameter_Cellxx.xlsx” and “z_predicted_Cellxx.xlsx”, which represent the two main outputs of the algorithm discussed in paper from Authors.

• The file “Circuit_parameter_Cellxx.xlsx” contains the nine circuit parameters, the corresponding fitting metrics and the aging-related parameters (LAM, LLI, CL) sorted for aging cycle and SOC level.
• The file “z_predicted_Cellxx.xlsx” contains the predicted values of the real and imaginary parts of the impedance for each considered frequency, sorted for aging cycle and SOC level.

For further information the reader is advised to rewiev the paper from Leonardi et Al, Automated electrochemical impedance spectroscopy fitting for quantitative analysis of degradation modes in lithium-ion batteries,
Journal of Energy Storage, Volume 154, Part A, 2026, 121144, https://doi.org/10.1016/j.est.2026.121144.