Lithium-Ion Conductors of the System LiCo1−xFexO2, Preparation and Structural Investigation

Holzapfel, Michael; Haak, Christian; Ott, A.

doi:10.1006/jssc.2000.9026

Cited by 36 publications

(27 citation statements)

References 43 publications

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“…The analysis of the FWHM for the Bragg peaks shows that the presence of the complexing agent in the synthesis of HT-LiCoO 2 leads to a high degree of crystallinity, good hexagonal ordering, and greater layered characteristics during the formation process. 57 The data shown in Table 1 and Figure 4 are consistent with the LiCoO 2 rhombohedral crystal system of the space group (166) , inorganic crystal structure database ICSD#51381, 63 and the Co 3 O 4 cubic crystal system of the space group (227) , ICSD#36256.…”

Section: Resultssupporting

confidence: 72%

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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Section: Resultssupporting

confidence: 72%

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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“…[33,34] This inspired us to developed protonconducting electrolyte in other layered oxide such as -LiFeO 2 . [35] In our experiment, it was found that new oxide with nominal composition LiFe 0. has been investigated to be used as potential cathode for molten carbonate fuel cells (MCFCs) due to its electronic conduction but its application is limited to the low conductivity. [36] LiAlO 2 is an insulator widely used as the electrolyte matrix for MCFCs.…”

Section: Introductionmentioning

confidence: 54%

“…This phenomenon is very different from the proton conduction in layered oxide Li x Al 0.5 Co 0.5 O 2 [33] because the -LiFeO 2 phase in the composite exhibits cubic disordered rock salt structure which is not a layered oxide. [35] The potential mobile channels for protons in layered oxides do not exist in the cubic -LiFeO 2 . It should be noted that proton conduction has been widely reported in materials which are not with layered structure.…”

Section: Resultsmentioning

confidence: 99%

High Ionic Conductivity in a LiFeO₂–LiAlO₂ Composite Under H₂/Air Fuel Cell Conditions

Lan

Tao

2014

Chemistry A European J

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This version is available at https://strathprints.strath.ac.uk/57676/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.uk condition. This provides a new approach to discover novel ionic conductors from composite materials derived from electronic conductors.

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“…(12) and by AlcaH ntara using a solid-state high-temperature reaction at 8003C (13). Using an indirect approach by Na>/Li> ionexchange, we succeeded in the preparation of the solid solution LiFe \V Co V O in the whole composition range (04x41) and reported its structural, physicochemical, and electrochemical characterization (14). The high-"eld magnetic properties of these samples have been presented in a previous work (15).…”

Section: Introductionmentioning

confidence: 91%

Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

Douakha

Holzapfel

Chappel

et al. 2002

Journal of Solid State Chemistry

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Lithium-Ion Conductors of the System LiCo1−xFexO2, Preparation and Structural Investigation

Cited by 36 publications

References 43 publications

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

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

High Ionic Conductivity in a LiFeO₂–LiAlO₂ Composite Under H₂/Air Fuel Cell Conditions

Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

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Lithium-Ion Conductors of the System LiCo1−xFexO2, Preparation and Structural Investigation

Cited by 36 publications

References 43 publications

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

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

High Ionic Conductivity in a LiFeO2–LiAlO2 Composite Under H2/Air Fuel Cell Conditions

Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

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High Ionic Conductivity in a LiFeO₂–LiAlO₂ Composite Under H₂/Air Fuel Cell Conditions