Impedance Analysis with Transmission Line Model for Reaction Distribution in a Pouch Type Lithium-Ion Battery by Using Micro Reference Electrode

Abstract

Electrochemical impedance spectroscopy (EIS) using an equivalent circuit is a powerful tool in the diagnosis of lithium-ion batteries (LIBs). However, LIBs have been increasingly used in applications requiring power higher than that used for conventional LIBs for portable electric devices. Considering this demand for LIBs, the ionic resistances in the electrodes, which raise a reaction distribution under high-power operation, are important. This consequently means EIS analysis should include ionic resistances in the electrodes in equivalent circuits. Additionally, the impedance response of LIBs are too complicated to be analyzed in detail because the impedance response consists of overlapping elemental processes such as chemical reactions and ion migration. This paper therefore presents an analysis of impedance responses, which are independently obtained by a micro reference electrode, by using a transmission line model (TLM) that possesses the ability to count the ionic resistances in the electrodes. Similar to the conventional Randles equivalent circuit, the equivalent circuit with TLM could fit the impedance responses simulated by the equivalent circuit with measured responses. This paper discusses the potential of EIS using an equivalent circuit coupled with a TLM for diagnosis of LIBs in power applications.

A Physically-Based Equivalent Circuit Model for the Impedance of a LiFePO4/Graphite 26650 Cylindrical Cell

“…18,21 In order to study electrode ageing mechanisms, Transmission Line Models (TLMs; a subset of ECMs) have previously been used to model the impedance response of porous electrodes infiltrated by a liquid electrolyte. 15,20,22,23 One important ability of these TLMs is the calculation of ionic resistance in the infiltrated pores R ion,L . The electronic resistance R el through the composite electrode is usually considered negligible compared to the ionic resistance.…”

Surface State Change of Lithium Metal Anode in Full Cell during Long Term Cycles

“…At all the spectra, semicircles or collapsed semicircles are observed in the high frequency region of >100 Hz, indicating charge transfer through the surface film formed on the anode and cathode. 39,40 The resistance derived from these films increased with increasing cycle numbers. In the low frequency region, which is considered to be related to the solid state diffusion of lithium ion in the electrode bulk, 41 a linear line at 100th cycle changes into a part of collapsed semicircle at 400th cycle, indicating that the lithium ion diffusion is gradually inhibited with increasing cycle numbers.…”

Critical Review of the Use of Reference Electrodes in Li-Ion Batteries: A Diagnostic Perspective

“…As mentioned above, EIS is the method of choice to study the electrochemical properties of various battery electrodes as a function of cycling or state of charge [54]. Positive electrode active materials including V6O13 [14,55], LiMn2O4 [56,57] [72,73], LiNi0.5Mn1.5O4 [74], LiNi0.5Mn0.3Co0.2O2 [36,75], and LiNi0.6Mn0.6Co0.2O2 [76], as well as negative electrode active materials, such as carbons [35,60,68,[77][78][79][80], graphite [16,31,[36][37][38]57,[62][63][64][65][66][67][68][69][70][71][72][73][74][75]81,82], Sn-containing composites [82,83], LiTi2(PO4)3 [15], Li4Ti5O12 [61], and Si-containing composites [34,84,85] have...…”

“…It has also been reported that overcharge conditions produce a high impedance at the positive electrode, while over discharge of the battery results in a higher impedance at the negative electrode [72]. Interestingly, when metallic Li is used as the negative electrode instead of a In general, three-electrode measurements have shown that the main contribution to the impedance of a LIB cell originates from the positive electrode [37,63,71,73,81]. The negative electrode, which generally comprises a graphitic active material, commonly exhibits a stable impedance contribution independent of the state of charge of the battery [63,71,73].…”