An Electrochemical Impedance Spectroscopic Study of the Electronic and Ionic Transport Properties of Spinel LiMn₂O₄

Abstract

Electrochemical impedance spectra (EIS) for lithium ion insertion and deinsertion in spinel LiMn 2 O 4 were obtained at different potentials and different temperatures during initial charge-discharge cycle. The results revealed that, at intermediate degrees of intercalation, three semicircles appeared in the Nyquist diagram. This new phenomenon has been investigated through EIS measurements as a function of temperature. It has found that the high frequency semicircle and the middle to high frequency semicircle begin to overlap each other above 20 °C, which indicates that the high frequency compressed semicircle commonly obtained at room temperature in the literature may consist of two semicircles. This signifies that the effects of the electronic and ionic transport properties of lithium intercalation materials clearly appear as separate features in the EIS spectra at low temperatures. A new equivalent circuit that includes elements related to the electronic and ionic transport, in addition to the charge transfer process, is proposed to simulate the experimental EIS data. The change of kinetic parameters for lithium ion insertion and deinsertion in spinel LiMn 2 O 4 as a function of potential in the first charge-discharge cycle is discussed in detail, and a modified model is proposed to explain the impedance response of the insertion materials for lithium ion batteries.

Diagnosis of Electrochemical Impedance Spectroscopy in Lithium-Ion Batteries

“…Nobili and co-workers [25,61,[72][73][74][75] suggested that the Nyquist plots of LiCoO 2 in the delithiated state should involve a third semicircle relating to the electronic propetries of the material, however, the three suggested semicircles could not be observed in their experimental results. In our previous work [126], as illustrated in Figure 2-5, at intermediate degrees of the first delithiation process in spinel LiMn 2 O 4 electrode, three semicircles are observed in the Nyquist diagram, and it was demonstrated that the semicircle in the middle to high frequency range (MHFS) should be attributed to the electronic properties of the material. Therefore, a modified model is put forward, as shown in Figure 2-6, and the EEC is illustrated in Figure 2-7.…”

“…In the past decades, EIS has been extensively used in the analysis of lithium battery systems, especially to predict the behavior of batteries, and to determine the factors limiting the performance of an electrode including its conductivity [75,126], charge-transfer properties [11,103,[117][118][119], properties of the passivating layer, etc. Numerous recent studies have been published on various aspects of the insertion electrodes used in lithium-ion batteries for the attempt to understand the origin of the observed capacity loss during extended cell cycling or storage [1,30,37,52,66,78,97].…”

Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography

“…Examples are X-ray diffractions tudies on structural changes in lithium manganese oxide (LMO)i nduced by Li (de)intercalation [1][2][3][4][5][6] and on the influence of dopants in LMO on the cycling performance [7] in addition to electrochemical impedances pectroscopy studies on the Li-insertion process in Li x Mn 2 O 4 to develop an atomic modelf or Li insertion. [8,9] Am ore detailed understanding of the processes determining battery performance requires the investigation of the individual battery components and their interaction. In the case of composite electrodes,f ocused ion-beam-based 3D tomographyi sasuitable methodt or eveal the exact distribution of differentp hases, including the active material, binder with conductive additive,a nd pores.…”

Investigation of Cr2O3as Anode Materials for Lithium-Ion Batteries by Electrochemical Impedance Spectroscopy

“…z E-mail: zhuangquanchao@126.com; qzhuang4@uwo.ca Electrochemical impedance spectroscopy (EIS) is one of the most powerful instrument in researching the electronic and ionic transport properties as well as lithiation and de-lithiation mechanism of the electrode materials based on the intercalation/de-intercalation mechanism and has been confirmed before. [16][17][18][19] Nevertheless, there is little report on electrode materials based on the conversion reaction mechanism analyzed by EIS. Here in this study, the electrode reaction mechanisms of commercial Cr 2 O 3 and carbon coating Cr 2 O 3 /C electrode is investigated systematically by EIS.…”