Structural properties and application in lithium cells of Li(Ni0.5Co0.5)1−Fe O2 (0 ≤ y ≤ 0.25) prepared by sol–gel route: Doping optimization

Abdel-Ghany, Ashraf E.; Hashem, Ahmed M.; Elzahany, Eman A.M.; Abuzeid, Hanaa M.; Indris, Sylvio; Nikolowski, Kristian; Ehrenberg, Helmut; Zaghib, Karim; Mauger, A.; Julien, C.

doi:10.1016/j.jpowsour.2016.04.087

Cited by 16 publications

(7 citation statements)

References 42 publications

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“…The Fe 3+ sites observed here have center shifts in the range of +0.33 to +0.35 mm/s. These values are consistent with earlier results for Fe 3+ -containing O3-NaMO 2 or LiMO 2 phases. , In the present work, it is confirmed that samples outside of composition ranges previously measured exclusively contain Fe 3+ and this has also been observed for many members of NaFe x Co 1– x O 2 , NaFe x (Co 0.5 Ni 0.5 ) 1– x O 2 , and NaFe x Ni 1– x O 2 solid solutions (not shown). In previous work, O3-Na y Ni 0.6 Co 0.4 O 2 was synthesized and deintercalated to produce y = 0.80 and 0.58 samples, where Ni and Co were determined to be in the +3 state .…”

Section: Resultssupporting

confidence: 93%

Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes

Thorne

Zheng

Lee

et al. 2018

ACS Appl. Mater. Interfaces

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The synthesis, structure, and electrochemistry in Na cells of NaFe MO positive electrode materials with M = Ni, CoNi, and Co are reported. In particular, the properties of O3-NaFeO-NaCoNiO solid solutions having compositions NaFe (CoNi)O with 0 ≤ x ≤ 0.5 are explored. It is found that the substitution of Fe in NaNiCoO causes an increase in first cycle energy density from 320 to 440 mWh/g in a 1.5-4.0 V test. However, capacity retention is generally reduced when x is increased for all M = Ni, CoNi, and Co. In general, NaFe MO samples with M = Co had the highest capacity retention for all values of x. Ex situ X-ray diffraction and Mössbauer results of as-prepared and charged materials are directly compared for NaFe (CoNi)O and NaFe CoO ( x = 0.4, 0.5). Iron was found to be in the +3 oxidation state in the as-prepared materials. A significant fraction of Fe is oxidized to Fe in these samples when they are charged to 4.0 V.

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Section: Resultssupporting

confidence: 93%

Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes

Thorne

Zheng

Lee

et al. 2018

ACS Appl. Mater. Interfaces

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“…However, the cation mixing tended to increase for the powder with solid solution of Fe. Similar to the report by Kobayashi et al, 19) Fe 3+ is considered to be responsible for the cation mixing. 6 shows the initial discharge capacity and capacity retention after 50 cycles.…”

Section: ) Powdersupporting

confidence: 85%

Preparation and electrode property of layered rock-salt type LiNi(1−x)/2Co(1−x)/2TixO2 and LiNi(1−x)/2Co(1−x<sub&g

Fujimoto

Nanbu

Yamaguchi

et al. 2022

J. Ceram. Soc. Japan

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Layered rock-salt LiNi (1¹x)/2 Co (1¹x)/2 Ti x O 2 (0 ¯x ¯0.1) and LiNi (1¹x)/2 Co (1¹x)/20.05 Fe 0.05 Ti x O 2 (0 ¯x ¯0.1) were prepared by the electrostatic spray deposition method, which is one of the solution processes, to investigate the correlation between these crystal structures and electrode properties of the multinary oxides with solid solution of Fe and Ti ions. Even with only 5 % solid solution of Fe, the cycle retention rate after 50 cycles decreased by 58 %. Regardless of Fe-substitution/non-substitution, the crystallite size of the powder calcined at 973 K under oxygen atmosphere became finer as the amount of Ti substitution increased. Although Ti ions do not contribute to redox, Ti-substituted materials are improved Li diffusion due to finer crystallite size, and show better discharge capacity and cycle performance as Ti content increased. Not only in the LiNiCo system, but also in the LiNiCoFe system, crystallite size refinement and improvement in initial discharge capacity and cycle performance were observed depending on the amount of Ti substitution, indicating that Ti ions contribute to lattice stabilization.

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“…2,4 The investigation of the structural aspects of the material is a crucial issue to better understand the electrochemical properties of the LiCoO 2 compound. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For example, the nature of the crystal, its size and shape, are directly related with its electrochemical characteristics. 2 The LiCoO 2 synthesized at low temperatures (LT), below 500 °C, presents a cubic spinel structure ( ), while the synthesis at high temperatures (HT) (above 500 °C), generates the rhombohedral structure with stratified layers ( ).…”

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confidence: 99%

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Freitas

Siqueira

Costa

et al. 2017

J. Braz. Chem. Soc.

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Lithium cobalt oxide, LiCoO 2 , widely used as cathode in lithium ion batteries was synthesized and their structural and electronic properties investigated. The crystalline powders were prepared by the sol-gel method with four complexing agents: citric acid, glycine, starch and gelatin. These syntheses were compared with the blank test (without complexing agent). The X-ray diffraction and vibrational spectroscopy allowed the identification of the rhombohedral phase LiCoO 2 ( ) as the only or principal crystalline component in all samples. A small fraction of a second phase of cubic spinel Co 3 O 4 was observed in the samples of starch, gelatin and the blank test. The Rietveld refinements showed small structural variations, indicating reduced influence of the complexing agents on the synthesis. The theoretical HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gap values are in agreement to those estimated by diffuse reflectance spectroscopy (DRS). The scanning electron microscopy (SEM) showed morphological pattern regardless of the complexing agent used, showing an alternative method.Keywords: LiCoO 2 , sol-gel method, XRD, Rietveld refinement, lithium ion batteries, DFT IntroductionLithium cobalt oxide, LiCoO 2 , has been the focus of many studies regarding their structural and electronic properties. [1][2][3][4][5][6][7][8] This system has interesting electrochemical features that allows a wide use as cathodes of lithium ion batteries. 2,4 The investigation of the structural aspects of the material is a crucial issue to better understand the electrochemical properties of the LiCoO 2 compound. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For example, the nature of the crystal, its size and shape, are directly related with its electrochemical characteristics. 2 The LiCoO 2 synthesized at low temperatures (LT), below 500 °C, presents a cubic spinel structure ( ), while the synthesis at high temperatures (HT) (above 500 °C), generates the rhombohedral structure with stratified layers ( ). Therefore, several authors usually classify these structures as LT-LiCoO 2 and HT-LiCoO 2 , respectively . 1,2,7,8,[18][19][20][21][22][23][24] The rhombohedral phase is characterized by a structure with alternating layers of cobalt and lithium cations intercalated with oxygen anions. 22 The lithium and cobalt(III) ions are arranged in intercalated layers (Figure 1a). The cobalt(III) ion is located at the octahedral sites, forming a strong bond with the neighboring oxygen anion to constitute the Co−O layers (Figure 1b). Finally, the lithium layers are intercalated between the CoO 2 plans. 1,3,4 The octahedral sites of these layers are occupied by lithium and cobalt(III) ions alternately that forms a sequential stacking with oxygen ion layers in a close packing of the ABCABC type ( Figure 1c). 4,5 This specific stacking arrangement leads to an environment equivalent for all ions, allowing the maximum charge delocalization and the minimal system energy. 1,3,4 The degree of crystal orde...

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Structural properties and application in lithium cells of Li(Ni0.5Co0.5)1−Fe O2 (0 ≤ y ≤ 0.25) prepared by sol–gel route: Doping optimization

Cited by 16 publications

References 42 publications

Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes

Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes

Preparation and electrode property of layered rock-salt type LiNi<sub>(1−</sub><i><sub>x</sub></i><sub>)/2</sub>Co<sub>(1−</sub><i><sub>x</sub></i><sub>)/2</sub>Ti<i><sub>x</sub></i>O<sub>2</sub> and LiNi<sub>(1−</sub><i><sub>x</sub></i><sub>)/2</sub>Co<sub>(1−</sub><i><sub>x</sub></i><sub&g

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

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Structural properties and application in lithium cells of Li(Ni0.5Co0.5)1−Fe O2 (0 ≤ y ≤ 0.25) prepared by sol–gel route: Doping optimization

Cited by 16 publications

References 42 publications

Synthesis and Electrochemistry of O3-type NaFeO2–NaCo0.5Ni0.5O2 Solid Solutions for Na-Ion Positive Electrodes

Synthesis and Electrochemistry of O3-type NaFeO2–NaCo0.5Ni0.5O2 Solid Solutions for Na-Ion Positive Electrodes

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

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Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes

Synthesis and Electrochemistry of O3-type NaFeO₂–NaCo_0.5Ni_0.5O₂ Solid Solutions for Na-Ion Positive Electrodes