NMR investigation on the motion of Li+ defects in LiCoO2 and LiNiO2

Nakamura, Kōichi; Yamamoto, Mituaki; Okamura, Keisuke; Michihiro, Yoshitaka; Nakabayashi, Ichiro; Kanashiro, Tatsuo

doi:10.1016/s0167-2738(99)00052-1

Cited by 25 publications

(20 citation statements)

References 16 publications

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“…5 This is because the magnetic ions contribute additional spin-lattice relaxation processes with considerably greater 1/T 1 fs than expected from only Li diffusion. 6,7 As a result, D Li estimated by 7 Li-NMR for LiCoO 2 and LiNiO 2 8 is three or four orders of magnitude smaller than the D Li predicted by first principles calculations, 9 while μ + SR yields higher D Li for the related compounds LiNiO 2 and LiCrO 2 , more in line with the theoretical predictions. 10 Very recent μ + SR work on the olivine-type lithium iron phosphate LiFePO 4 , which is heavily investigated as a positive electrode material for the near-future Li-ion battery, 11,12 showed that D Li ∼ 3.6 × 10 −10 cm 2 /s at 300 K, 13 a result confirmed by another group.…”

Section: Introductionsupporting

confidence: 72%

“…2 shows representative ZF and LF spectra for LiMPO 4 with M = Fe, Co, or Ni obtained at 100, 300, and 480 K. At each T , the ZF spectrum of LiFePO 4 and LiCoPO 4 consists of a fast relaxing signal in the early-time domain and a slowly relaxing signal. The former is caused by a fluctuating magnetic field (H 3d int ) due to the 3d electrons of the M 2+ ions, while the latter is caused by nuclear magnetic fields (H N int ) due to 6 Li, 7 Li, 57 Fe, 59 Co, 61 Ni, and 31 P. Since the natural abundance of 57 Fe, 59 Co, and 61 Ni is 2.2%, 100%, and 1.14%, respectively, the effect of 57 Fe and 61 Ni on H N int is negligible small. Note that the ZF spectrum of LiNiPO 4 TABLE I.…”

Section: Resultsmentioning

confidence: 99%

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Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

et al. 2012

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In order to study the diffusive nature of lithium transition-metal phospho-olivines, we measured muon-spin relaxation (μ + SR) spectra for the polycrystalline LiMPO 4 samples with M = Mn, Fe, Co, or Ni in the temperature range between 50 and 500 K. The μ + SR spectra under zero applied field are strongly affected by the magnetic moments of the 3d electrons in the M 2+ ions so that, for LiMnPO 4 , it was difficult to detect the relaxation change caused by the diffusion due to the large Mn 2+ (S = 5/2) moments. However, diffusive behavior was clearly observed via the relaxation due to nuclear dipolar fields above ∼150 K for LiFePO 4 , LiCoPO 4 , and LiNiPO 4 as S decreased from 2 to 1. From the temperature dependence of the nuclear field fluctuation rate, self-diffusion coefficients of Li + ions (D Li ) at 300 K and its activation energy (E a ) were estimated, respectively, as ∼3.6(2) × 10 −10 cm 2 /s and E a = 0.10(2) eV for LiFePO 4 , ∼1.6(1) × 10 −10 cm 2 /s and E a = 0.10(1) eV for LiCoPO 4 , and ∼2.7(4) × 10 −10 cm 2 /s and E a = 0.17(2) eV for LiNiPO 4 , assuming that the diffusing Li + ions jump between the regular site and interstitial sites.

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Section: Introductionsupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

et al. 2012

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“…D of Li + ions (D Li ) in solids is usually evaluated by 7 Li-NMR. However, for materials containing magnetic ions, Li-NMR provides very limited information on D Li , because of the effect of electron spins on the spin-lattice relaxation rate (1/T 1 ) [1,2]. In fact, D Li estimated by 7 Li-NMR for LiCoO 2 and LiNiO 2 [3] is known to be three or four orders of magnitude smaller than the D Li predicted by first principles calculations.…”

Section: Introductionmentioning

confidence: 99%

“…However, for materials containing magnetic ions, Li-NMR provides very limited information on D Li , because of the effect of electron spins on the spin-lattice relaxation rate (1/T 1 ) [1,2]. In fact, D Li estimated by 7 Li-NMR for LiCoO 2 and LiNiO 2 [3] is known to be three or four orders of magnitude smaller than the D Li predicted by first principles calculations. [4] This means the lack of correct D Li for the positive electrode materials of Li-ion batteries, which include transition metal ions in order to compensate charge neutrality during Li + intercalation and deintercalation reaction.…”

Section: Introductionmentioning

confidence: 99%

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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“…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].…”

Section: Introductionmentioning

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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NMR investigation on the motion of Li+ defects in LiCoO2 and LiNiO2

Cited by 25 publications

References 16 publications

Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

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

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NMR investigation on the motion of Li+ defects in LiCoO2 and LiNiO2

Cited by 25 publications

References 16 publications

Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

Diffusive behavior in LiMPO4withM=Fe, Co, Ni probed by muon-spin relaxation

Ion Diffusion in Solids Probed by Muon-Spin Spectroscopy

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

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