Effect of iron on delithiation in LixCo<sub>1−y</sub>FeyO<sub>2</sub>. Part 1: in-situ electrochemical and X-ray diffraction study

Holzapfel, Michael; Strobel, Pierre; Darie, Céline; Wright, Jonathan P.; Morcrette, Mathieu; Chappel, Eric; Anne, M.

doi:10.1039/b307671g

Cited by 6 publications

(14 citation statements)

References 40 publications

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“…The preparation of the samples and the plastic batteries has been carried out as described in detail previously. 27 The prepared LiCo 12y Fe y O 2 compounds were used here as starting materials to study the delithiated Li x Co 12y Fe y O 2 systems with y ~0.1, 0.2 and 0.4. These compounds are abbreviated LCF1, LCF2 and LCF4, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…LiCo 12y Fe y O 2 could be an interesting alternative in this respect, if the stabilising effect of cobalt was maintained and indeed numerous works have been devoted to investigate this system. The synthesis and the structural and physicochemical characterisation of these compounds have already been discussed [15][16][17][18][19][20][21][22][23][24][25][26] in the first part of this series, 27 where the in-situ X-ray diffraction study of the LiCo 12y Fe y O 2 solid solution is described. Upon oxidation of Fe 31 , Fe 41 should be formed, which is a d 4 -high spin system, showing, in principle, a Jahn-Teller effect, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…The results for these in-situ XANES and EXAFS experiments are presented and discussed in this paper, whereas the X-ray diffraction data are presented in the first article. 27…”

Section: Introductionmentioning

confidence: 99%

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Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Holzapfel¹,

Proux²,

Strobel³

et al. 2004

J. Mater. Chem.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Holzapfel¹,

Proux²,

Strobel³

et al. 2004

J. Mater. Chem.

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“…These attempts have met varying degrees of success. 15,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] 15,[20][21][22][23]26,[28][29][30] Most studies attribute the improvements in LCO cycling performance to Mg either providing structural stability 15,21,26,27 or improving the conductivity of the material. 20,23,29,30 Recently, Shim et al reported a retention of 85% capacity after 500 cycles and 60% after 700 cycles in 2900 mAh prismatic full cells (LCO/graphite) cycling up to 4.4 V (4.48 V vs Li/Li + ) utilizing a combination of ionic conductor coating and Mg doping.…”

mentioning

confidence: 99%

Synthesis of Mg and Mn Doped LiCoO₂and Effects on High Voltage Cycling

Liu

Shunmugasundaram

et al. 2017

J. Electrochem. Soc.

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LiCo 1-2x Mg x Mn x O 2 (0 ≤ x ≤ 0.05) materials were prepared from Co 1-2x Mg x Mn x (OH) 2 (0 ≤ x ≤ 0.05) co-precipitated precursor materials by mixing precursor materials with stoichiometric amounts of Li 2 CO 3 and heating to 900 • C for 10 h. All precursor and lithiated materials were characterized by Scanning Electron Microscopy, X-ray Diffraction (XRD), Inductively Coupled PlasmaOptical Emissions Spectroscopy and electrochemical testing. In situ XRD was performed on LiCo 1-2x Mg x Mn x O 2 (x = 0, 0.02, 0.05) electrodes while cycling to study the effects of substitution on phase transitions and unit cell variations. Increasing Mg/Mn substitution in the material was found to slightly increase the 1 st charge capacity, decrease the 1 st discharge capacity and increase the 1 st cycle irreversible capacity (3.6 V-4.7 V). Cells with even 1% Mg/Mn doping were shown to have markedly improved cycling performance, and results suggest that the improvements stem from suppressing the cell impedance growth, not from the suppression of the O3-O6-O1 phase transitions. Lithium ion (Li-ion) batteries are used to power cell phones, laptops, other portable electronics, electric vehicles and grid storage. With an ever-increasing demand for energy, battery manufacturers and researchers constantly look for ways to increase the energy density while maintaining a long lifetime. LiCoO 2 (LCO) positive electrode materials, proposed by Mizushima et al. in 1980, 1 have been utilized since the commercialization of Li-ion battery technology by Sony in 1991. 2 Significant improvements have been made since then, but commercially available batteries never push LCO electrodes past 4.48 V (vs Li/Li + ), corresponding to the deintercalation/intercalation of ∼0.7 Li (per LCO) or a capacity of ∼190 mAh/g (out of a theoretical capacity of ∼274 mAh/g). In order to unlock more capacity and increase the energy density, the LCO electrodes have to cycle to voltages above 4.5 V (vs Li/Li + ). However, pushing cells with LCO electrodes to an even higher voltage result in a dramatic decrease in long term cycling performance. [3][4][5][6][7][8][9] There are multiple causes for this drop in performance, including structural instability of highly delithiated LCO,[6][7][8]10,11 electrolyte oxidation 5-7,9,10,12,13 and Co dissolution. 3,5,7,8,14,15 To further understand the structural instability that arises from high voltage cycling, X-ray diffraction (XRD) has been instrumental in studying the unit cell lattice parameter changes and phase formations. 10,11,16,17 Theoretical work has also confirmed the majority of these occurrences and helped shed light in understanding phase formation at low lithium content. 18,19 As Li deintercalates from LCO, the material undergoes a series of phase changes. The first is an insulatormetal transition, resulting in a 2-phase region. 10,16 As the material continues to deintercalate, LCO will undergo an order-disorder transition around 0.5 Li.16,18 Both of these transitions occur reversibly and are not detrimental to cycli...

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“…Holzapfel et al have also studied such samples, utilising in-situ X-ray diffraction, XANES and EXAFS studies to determine the structural changes and changes in local symmetry and oxidation states on cycling. 5,6 From EXAFS studies it was shown that whereas little change happens to the cobalt environment, a significant distortion occurs in the Fe environment on delithiation, which is attributed to the Jahn-Teller effect for Fe 4+ , which is formed on delithiation. The results suggest that as the Fe content increases, so the oxidation of Fe 3+ becomes more difficult.…”

Section: Cathode Materialsmentioning

confidence: 99%

24 Conducting solids

Sansom

Slater

2005

Annu. Rep. Prog. Chem., Sect. A

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Effect of iron on delithiation in LixCo_1−yFeyO₂. Part 1: in-situ electrochemical and X-ray diffraction study

Cited by 6 publications

References 40 publications

Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Synthesis of Mg and Mn Doped LiCoO₂and Effects on High Voltage Cycling

24 Conducting solids

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Effect of iron on delithiation in LixCo1−yFeyO2. Part 1: in-situ electrochemical and X-ray diffraction study

Cited by 6 publications

References 40 publications

Effect of iron on delithiation in LixCo1−yFeyO2. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Effect of iron on delithiation in LixCo1−yFeyO2. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Synthesis of Mg and Mn Doped LiCoO2and Effects on High Voltage Cycling

24 Conducting solids

Contact Info

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About

Effect of iron on delithiation in LixCo_1−yFeyO₂. Part 1: in-situ electrochemical and X-ray diffraction study

Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Synthesis of Mg and Mn Doped LiCoO₂and Effects on High Voltage Cycling