Written by DZ

EIS quality indicator by Bio-Logic, Because linearity matters

THD, an EIS quality indicator

Electrochemical impedance spectroscopy (EIS) measurements at two different AC amplitudes (50 mA & 400 mA) are performed on the same Li-ion battery cell. The non-linearity of the cell at low frequency is evident in the Nyquist plot above.

After an equivalent circuit fit analysis, the charge transfer resistance is over-estimated by 8% with the 400 mA AC amplitude measurement. The THD indicator can be used to detect this non-linearity and help optimize the stimulation amplitude

Click here to view the online video detailing how Bio-Logic’s quality indicators, THD, NSD & NSR can help with the validation of EIS measurements.

Click here to view a Z fit tutorial by Bio-Logic.

Please don’t hesitate to contact us if you are based in Scandinavia and would like to have more info about the THD.