Studies of electrochemical properties of lithium cobalt oxide

Yao, C.Y.; Kao, Tune-Hune; Cheng, Chih Chia; Chen, J.M.; Hurng, W.‐M.

doi:10.1016/0378-7753(94)02132-m

Cited by 20 publications

(21 citation statements)

References 4 publications

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“…5(b)]. Note that the prediction by first-principle calculations at 300 K is likely to agree with the powder data [5][6][7][8][9], if we assume that Θ ∼ 100 [4]. However, reliable data on an activation energy (E a ) of Li-diffusion in Li x CoO 2 are still unavailable [28], because it is very difficult to measure electrochemical properties for Li x CoO 2 in a wide T range, particularly above ambient T , due to thermal decomposition of a liquid electrolyte.…”

Section: X Coo 2 [16]supporting

confidence: 53%

“…the electrolyte as well as the compositions of the positive and negative electrodes. As a result, the reportedD Li for Li x CoO 2 ranges from 4×10 −8 to 10 −10 cm 2 s −1 for powder samples [5][6][7][8][9] and from 2.5 × 10 −11 to 2 × 10 −13 cm 2 s −1 for thin films [10][11][12][13] at ambient T . This is a highly unsatisfactory situation, since D Li is one of the primary parameters that govern the charge and discharge rate of a Li-ion battery, particularly in the case of future solid state batteries.…”

Section: Introductionmentioning

confidence: 99%

“…Figures 4(a) and 4(b) show the zero field (ZF-) and longitudinal field (LF-) µ + SR spectrum for the Li 0.73 CoO 2 sample obtained at 100 and 225 K. At 100 K, the ZF-spectrum exhibits a typical KuboToyabe (KT) behavior, meaning that the implanted muons see the internal magnetic field (H int ) due to the nuclear magnetic moments of 7 Li, 6 Li and 59 Co. The applied LF clearly reduces the relaxation rate by decoupling H int .…”

Section: X Coo 2 [16]mentioning

confidence: 99%

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Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Sugiyama

2013

J. Phys. Soc. Jpn.

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Diffusion of Li+ ions in solids is a basic principle behind the operation of Li-ion batteries. Although a diffusion coefficient of Li + (D Li ) in solids is usually evaluated by 7 Li-NMR, difficulties arise for materials that contain magnetic ions. This is because the magnetic ions contribute additional spinlattice relaxation processes that are considerably larger than the 1/T 1 expected from only Li diffusion. As a result, it is very difficult to estimate correct D Li by Li-NMR, although D Li is one of the primary parameters that govern the charge and discharge rate of a Li-ion battery, particularly for the case of a future solid-state battery. We have, therefore, initiated to measure D Li in solids with muon-spin relaxation (µSR). Here, we summarize our µSR work on Li-diffusion and compare the µSR result with that obtained by QENS from the viewpoint of time window.

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Section: X Coo 2 [16]supporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Section: X Coo 2 [16]mentioning

confidence: 99%

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Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Sugiyama

2013

J. Phys. Soc. Jpn.

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“…Low temperature voltammetry has also been a very useful technique for studying thermally unstable species, detecting electrochemically produced intermediates, and probing the redox reactions in solvents with very low polarity [9][10][11][12][13]. The possibility of studying the electrochemical features of different electrolytes at lowered temperatures attracts also huge attention in the fields of lithium-ion batteries [2,14]. The low temperature voltammetry is currently seen as a powerful alternative to fast-scan protein-film voltammetry [6,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Protein-film voltammetry: A theoretical study of the temperature effect using square-wave voltammetry

Gulaboski

Lovrić²,

Mirčeski³

et al. 2008

Biophysical Chemistry

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Square-wave voltammetry of surface redox reactions is considered as an adequate model for a protein-film voltammetric setup. Here we develop a theoretical approach to analyze the effects of temperature on squarewave voltammograms. The performed simulations address the surface redox reactions featuring slow, modest and fast electron transfer. The theoretical calculations show that the temperature affects the squarewave voltammetric responses in a complex way resulting in a variety of peak shapes. Temperature effects on the phenomena known as "quasireversible maximum" and "split SW peaks" are also analyzed. The simulated results can be used to analyze the redox mechanisms and kinetic parameters of electron transfer reactions in protein-film criovoltammetry and other surface-confined redox systems. Our analysis also shows how "abnormal" features present in some square-wave voltammetric studies can easily be misinterpreted by postulating "multiple species", "stable radicals", or additional processes. Finally we provide a simple algorithm to use the "quasireversible maximum" to determine the activation energy of electron transfer reactions by surface redox systems.

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“…for Li x CoO 2 ranges from 4 × 10 −8 to 10 −10 cm 2 s −1 for powder samples [7][8][9][10][11] and from 2.5 × 10 −11 to 2 × 10 −13 cm 2 s −1 for thin films [12][13][14][15] at ambient T . In order to profoundly understand the physics behind the operation principle of battery materials, it is imperative to have a reliable probe to measure D Li for all the components of the battery as a function of both Li content as well as T .…”

Section: LImentioning

confidence: 99%

A novel tool for detecting Li diffusion in solids containing magnetic ions;μ⁺SR study on Li_xCoO₂

Sugiyama

Mukai

Ikedo

et al. 2010

J. Phys.: Conf. Ser.

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Abstract. The diffusion coefficient of Li+ ions (DLi) in the battery material LixCoO2 has been investigated by means of muon-spin relaxation (µ + SR), because DLi for positive electrode materials has not been determined correctly so far. Based on performing the experiments in zerofield and weak longitudinal-fields at temperatures up to 400 K, we determined the fluctuation rate (ν) of the fields on the muons due to their interaction with the nuclear moments. Combined with susceptibility data and electrostatic potential calculations, clear Li + ion diffusion was detected above ∼ 150 K. The DLi estimated from ν was in very good agreement with predictions from first-principles calculations, and we present the µ + SR technique as a novel and optimal probe to detect DLi of unique usefulness for materials containing magnetic ions. IntroductionIn spite of a long research history on lithium insertion materials for Li-ion batteries [1, 2], e.g., LiCoO 2 , LiNiO 2 , and LiMn 2 O 4 , one of their most important intrinsic physical properties, the Li + ions diffusion coefficient (D Li ), has not yet been determined with any reliability. Although Li NMR is a powerful technique to measure D Li for non-magnetic materials, it is particularly difficult to evaluate D Li for materials containing magnetic ions, because the magnetic ions induce additional pathways for the spin-lattice relaxation rate (1/T 1 ), resulting in huge 1/T 1 compared with that expected for only the diffusive motion of Li ions.Such difficulty was clearly evident in the 1/T 1 (T ) curve for LiCoO 2 and LiNiO 2 [3,4], and, for that reason, D Li was instead estimated from the Li-NMR line width [5]. However, since the line width, i.e., the spin-spin relaxation rate (1/T 2 ) is also affected by the magnetic ions, the D Li obtained by Li-NMR for LiCoO 2 (= 1 × 10 −14 cm 2 s −1 at 400 K) is approximately four orders of magnitude smaller than predicted by first-principles calculations [6]. Since lithium insertion materials always include transition metal ions, in order to maintain charge neutrality during the extraction and/or insertion of Li + ions, it is consequently very difficult to determine D Li for these compounds unambiguously by Li-NMR.On the other hand, the chemical diffusion coefficient (D chem

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Studies of electrochemical properties of lithium cobalt oxide

Cited by 20 publications

References 4 publications

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Protein-film voltammetry: A theoretical study of the temperature effect using square-wave voltammetry

A novel tool for detecting Li diffusion in solids containing magnetic ions;μ⁺SR study on Li_xCoO₂

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Studies of electrochemical properties of lithium cobalt oxide

Cited by 20 publications

References 4 publications

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

Protein-film voltammetry: A theoretical study of the temperature effect using square-wave voltammetry

A novel tool for detecting Li diffusion in solids containing magnetic ions;μ+SR study on LixCoO2

Contact Info

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A novel tool for detecting Li diffusion in solids containing magnetic ions;μ⁺SR study on Li_xCoO₂