can anyone please share an answer or include a paper reference on the relationship between lithium-ion battery cycling and impedance spectra. I am more interested in EIS (solution resistance, charge transfer resistance, and double-layer capacitance).
Hi Dhevati,
let's differentiate the real (ohmic) resistance and imaginary (quasi capacitive) part of impedance for clarity now. During cycling, the following tends to occur:
1.) Rs electrolyte (solution) resistance increases quite linearly with the cycles. This is caused by several reasons but due to the depletion of Li-ion on anode surface that forms the so called SEI layer. Considering EIS measurement, this introduces a shift from left to right on the real axis.
2.) Rct charge transfer resistance behaves similarly since it represents the resistance between the electrode-electrolyte surface where the SEI establishes, by the way. Using EIS measurements, there is a forming small semi-circle around 250 - 20 Hz that is proportional with the SEI layer thickness. This can be modeled by an auxiliary RC subsystem in the Randles equivalent circuit in series with the standard Rct-Cdl subsystem. The time-constant of this additional RC subsystem adds to the standard double-layer time constant.
3.) Double-layer capacity decreases since the total active area of the electrodes decrease with usage. Also, double-layer capacity can be considered as a part of the total battery capacity that is also decreasing with aging.
Besides cycling, the overall look of the EIS spectra has a strong dependency on SOC, temperature and last but not least the cell structure (e.g. porosity, thicknesses, construction type and so on). One should bear in mind these effects when evaluate the spectra.
As a reference, NASA has been carried out tests on aging with 3 types of batteries. They have concluded that these parameters change quite linearly with capacity withdrawed.
I hope I could help.
Thank You for the answer Bence Csomos Can you please share the research paper or article of NASA where it was discussed. It would be highly helpful.
Hi,
here is the reference for the NASA article that I mentioned:
Brian Bole, Chetan S. Kulkarni, Matthew Daigle, Adaptation of an Electrochemistry-based Li-Ion Battery Model to Account for Deterioration Observed Under Randomized Use, ANNUAL CONFERENCE OF THE PROGNOSTICS AND HEALTH MANAGEMENT SOCIETY 2014
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