Advanced Electrochemical Impedance Spectroscopy for the Aging Study of Commercial Li Ion Batteries

Description

Electrochemical impedance spectroscopy is the most promising non-destructive method for lithium ion battery diagnosis and materials characterization due to its simple instrumental requirements and powerful output. However, it is not easy to obtain reliable impedance data from the battery system because of its complexity. Many artefacts can be induced by the experimental procedures and the cell design.
In this work, EIS is performed by using the in-house developed multisine technique: Odd Random Phase EIS (ORP-EIS) [1]. Comparing with classical EIS measurements, ORP-EIS has the advantage that additional information can be quantitatively obtained: the level of disturbing noise, the level of the non-linear distortions and the level of the non-stationary behavior. Based on this information, the data quality can be directly evaluated. Additionally, the modeling procedure can be also benefit from this method. By comparing the residual values between experiment and model with the noise levels, the model is also statistically evaluated (see Fig.1). Many efforts have been put in optimizing the experimental protocol for the compact “sandwich” cell design. The conclusion agrees with Levi [2]: the impedance of individual battery electrodes should be measured in symmetric 2-electrodes cells.
In this work, a comprehensive aging study of Li4Ti5O12 /Li(NiCoAl)O2 (LTO/NCA) lithium ion batteries is carried out with a set of commercial pouch cells (5 Ah). It includes both cycling aging and calendar aging with varied aging conditions. These aged batteries are post-mortem analyzed by different techniques. Multiple ORP-EIS experiments are performed with different state-of-charge (SOC) levels for both anode and cathode materials. By fitting with the equivalent circuit model, the charge-transfer resistance Rct which is corresponding to the kinetic parameter is identified. The Rct of LTO shows subtle differences but NCA shows significant variation with different SOC levels due to the complex microstructure changes. By comparing with aged electrodes, the changes of the kinetic parameter can be quantified regarding to the different aging condition.

[1] Van Ingelgem, Yves, Els Tourwé, Orlin Blajiev, Rik Pintelon, and Annick Hubin. "Advantages of odd random phase multisine electrochemical impedance measurements." Electroanalysis 21, no. 6 (2009): 730-739.
[2] Levi, Mikhael D., Vadim Dargel, Yuliya Shilina, Doron Aurbach, and Ion C. Halalay. "Impedance Spectra of Energy-Storage Electrodes Obtained with Commercial Three-Electrode Cells: Some Sources of Measurement Artefacts." Electrochimica Acta 149 (2014): 126-135.

Periode	20 mrt 2017
Evenementstitel	20th Topical Meeting of the International Society of Electrochemistry: Advances in Lithium and Hydrogen Electrochemical Systems for Energy Conversion and Storage
Evenementstype	Conference
Locatie	Buenos Aires, Argentina
Mate van erkenning	International