High-Voltage LiNi1/2Mn3/2O4 Spinel: Cationic Order and Particle Size Distribution

Ivanova, Svetlana; Zhecheva, E.; Stoyanova, Р.; Nihtianova, D.; Wegner, Sebastian; Tzvetkova, Pavleta; Simova, Svetlana

doi:10.1021/jp208976h

Cited by 59 publications

(38 citation statements)

References 62 publications

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“…According to the previous studies, they can be assigned to the Li ions in a crystallographic regular environment for P4 3 32 structure surrounded by 3Ni 2+ / 9Mn 4+ ions, and in an irregular environment where the Li ion is surrounded by 2Ni 2+ /10Mn 3+,4+ ions or 3Ni 2+ /9Mn 3+,4+ , respectively. 10,28,52,53 The latter environment was observed due to incomplete Ni/Mn ordering in the ordered spinel structure and/or small deviation from Ni/Mn stoichiometry related to the formation of trivalent Mn 3+ ion. It is noted that the spectrum we obtained is similar in shape to that of 52 The presence of the minor signal suggests that the P4 3 32 ordered spinel can accommodate a small amount of Ni/Mn disordering, which may be dispersed in the structure as nanoscale domains.…”

Section: Resultsmentioning

confidence: 99%

“…It is noted that the spectrum we obtained is similar in shape to that of 52 The presence of the minor signal suggests that the P4 3 32 ordered spinel can accommodate a small amount of Ni/Mn disordering, which may be dispersed in the structure as nanoscale domains. 12,53 On the other hand, we believe that another minor signal at 710 ppm come from the impurity phase such as Li x Ni 1−x O 7,14 or LiNiO 2 28 (16% of total Li), because this signal shows a strong dipolar interaction different from the others, and still exists in the spectrum of the 258 mAh/g-discharged sample (this signal is overlapped with the other peaks at 40 kHz MAS in Figure 5b; see also Figure S21d). 28 Charging to 15 mAh/g produced a small shift of the main signal to lower frequency (925 ppm), and a disappearance of the 870 ppm signal (Figure 5a).…”

Section: Resultsmentioning

confidence: 99%

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Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy

et al. 2015

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Delithiation and lithiation behaviors of ordered spinel LiNi 0.5 Mn 1.5 O 4 and disordered spinel LiNi 0.4 Mn 1.6 O 4 were investigated by using in situ (in operando) 7 Li NMR and ex situ 6 Li MAS NMR spectroscopy. The in situ 7 Li monitoring of the ordered spinel revealed a clear appearance and subsequent disappearance of a new signal from the welldefined phase Li 0.5 Ni 0.5 Mn 1.5 O 4 , suggesting the two-phase reaction processes among Li 1.0 Ni 0.5 Mn 1.5 O 4 , Li 0.5 Ni 0.5 Mn 1.5 O 4 , and Li 0.0 Ni 0.5 Mn 1.5 O 4 . Also, for the disordered spinel, Li 0.5 Ni 0.4 Mn 1.6 O 4 was identified with a broad distribution in Li environment. High-resolution 6 Li MAS NMR spectra were also acquired for the delithiated and lithiated samples to understand the detailed local structure around Li ions. We suggested that the nominal Li-free phase Li 0.0 Ni 0.5 Mn 1.5 O 4 can accommodate a small amount of Li ions in its structure. The tetragonal phases Li 2.0 Ni 0.5 Mn 1.5 O 4 and Li 2.0 Ni 0.4 Mn 1.6 O 4 , which occurred when the cell was discharged down to 2.0 V, were very different in the Li environment from each other. It is found that 6,7 Li NMR is highly sensitive not only to the Ni/Mn ordering in LiNi 0.5 Mn 1.5 O 4 but also to the valence changes of Ni and Mn on charge−discharge process.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy

et al. 2015

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“…With respect to this regard, LiNi 0.5 Mn 1.5 O 4 (LNMO) is a promising cathode material 1–3 because it has a high redox potential of ~4.7 V, which makes its energy density (650 W∙h/kg) 20% higher than that of conventional LiCoO 2 . Recent studies have shown the promise of Li-ion batteries based on this material, especially composition−structure relationship with electrochemical performance 3–9 . The electrochemical properties of LNMO spinel depend on its structure such as the degree of Ni/Mn ordering 3, 6, 7, 10 and the presence of Mn 3+ ions 4, 11 .…”

Section: Introductionmentioning

confidence: 99%

Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni

Lee

Dupré

Avdeev

et al. 2017

Sci Rep

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We determined how Li doping affects the Ni/Mn ordering in high-voltage spinel LiNi0.5Mn1.5O4(LNMO) by using neutron diffraction, TEM image, electrochemical measurements, and NMR data. The doped Li occupies empty octahedral interstitials (16c site) before the ordering transition, and can move to normal octahedral sites (16d (4b) site) after the transition. This movement strongly affects the Ni/Mn ordering transition because Li at 16c sites blocks the ordering transition pathway and Li at 16d (4b) sites affects electrostatic interactions with transition metals. As a result, Li doping increases in the Ni/Mn disordering without the effect of Mn3+ ions even though the Li-doped LNMO undergoes order-disorder transition at 700 °C. Li doping can control the amount of Ni/Mn disordering in the spinel without the negative effect of Mn3+ ions on the electrochemical property.

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“…The spectrum exhibits sharp peaks near 855 eV (2p 3/2 ) and 873 eV (2p 1/2 ), with the energy difference (spin-orbit splitting) of 18 eV, suggesting that the Ni ions in nickel-ferrites mostly have a valence of +2. The peak near 862 eV, as marked by the asterisk (*), is identified as a major satellite to the 2p 3/2 main line of Ni 2+ ion [8,9]. Considering the observed reduction of Fe (B) ion in ferrimagnetic Fe 3 O 4 occupies a minority-spin t 2g state that is located close to E F ; while the majority-spin d states are completely filled with five electrons.…”

Section: Resultsmentioning

confidence: 99%

Structural Phase Transition, Electronic Structure, and Magnetic Properties of Sol-gel-prepared Inverse-spinel Nickel-ferrites Thin Films

Kim¹,

Kim²,

Kim³

2014

Journal of Magnetics

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X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) were used to investigate the influence of Ni ions on the structural, electronic, and magnetic properties of nickelferrites (Ni x Fe 3-x O 4 ). Spinel Ni x Fe 3-x O 4 (x ≤ 0.96) samples were prepared as polycrystalline thin films on Al 2 O 3 (0001) substrates, using a sol-gel method. XRD patterns of the nickel-ferrites indicate that as the Ni composition increases (x > 0.3), a structural phase transition takes place from cubic to tetragonal lattice. The XPS results imply that the Ni ions in Ni x Fe 3-x O 4 substitute for the octahedral sites of the spinel lattice, mostly with the ionic valence of +2. The minority-spin d-electrons of the Ni 2+ ions are mainly distributed below the Fermi level (E F ), at around 3 eV; while those of the Fe 2+ ions are distributed closer to E F (~1 eV below E F ). The magnetic hysteresis curves of the Ni x Fe 3-x O 4 films measured by VSM show that as x increases, the saturation magnetization (M s ) linearly decreases. The decreasing trend is primarily attributable to the decrease in net spin magnetic moment, by the Ni 2+ (2 µ B ) substitution for octahedral Fe 2+ (4 µ B ) site.

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High-Voltage LiNi_1/2Mn_3/2O₄ Spinel: Cationic Order and Particle Size Distribution

Cited by 59 publications

References 62 publications

Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy

Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy

Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni

Structural Phase Transition, Electronic Structure, and Magnetic Properties of Sol-gel-prepared Inverse-spinel Nickel-ferrites Thin Films

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High-Voltage LiNi1/2Mn3/2O4 Spinel: Cationic Order and Particle Size Distribution

Cited by 59 publications

References 62 publications

Delithiation/Lithiation Behavior of LiNi0.5Mn1.5O4 Studied by In Situ and Ex Situ 6,7Li NMR Spectroscopy

Delithiation/Lithiation Behavior of LiNi0.5Mn1.5O4 Studied by In Situ and Ex Situ 6,7Li NMR Spectroscopy

Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni

Structural Phase Transition, Electronic Structure, and Magnetic Properties of Sol-gel-prepared Inverse-spinel Nickel-ferrites Thin Films

Contact Info

Product

Resources

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High-Voltage LiNi_1/2Mn_3/2O₄ Spinel: Cationic Order and Particle Size Distribution

Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy

Delithiation/Lithiation Behavior of LiNi_0.5Mn_1.5O₄ Studied by In Situ and Ex Situ ^6,7Li NMR Spectroscopy