Effect of P2O5 and AlPO4 Coating on LiCoO2 Cathode Material.

Cho, Jaephil; Lee, Joon‐Gon; Kim, Byoungsoo; Park, Byungwoo

doi:10.1002/chin.200345018

Cited by 6 publications

(6 citation statements)

References 1 publication

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“…38 It is also known that DAP can be thermally decomposed to P 2 O 5 above 400 °C. 39 Hence, the actual product that reacted with the Li residues is P 2 O 5 , not DAP. The P 2 O 5 −Li residue−O 2 phase diagram in Figure 6b Table I According to the analysis of the product phases in the reactions of the MPs with the Li residues, Li 3 PO 4 is a frequently generated phase, as shown in Table I.…”

Section: Resultsmentioning

confidence: 99%

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Min

Seo

Choi

et al. 2017

ACS Appl. Mater. Interfaces

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Ni-rich layered oxides are attractive materials owing to their potentially high capacity for cathode applications. However, when used as cathodes in Li-ion batteries, they contain a large amount of Li residues, which degrade the electrochemical properties because they are the source of gas generation inside the battery. Here, we propose a computational approach to designing optimal coating materials that prevent gas evolution by removing residual Li from the surface of the battery cathode. To discover promising coating materials, the reactions of 16 metal phosphates (MPs) and 45 metal oxides (MOs) with the Li residues, LiOH, and LiCO are examined within a thermodynamic framework. A materials database is constructed according to density functional theory using a hybrid functional, and the reaction products are obtained according to the phases in thermodynamic equilibrium in the phase diagram. In addition, the gravimetric efficiency is calculated to identify coating materials that can eliminate Li residues with a minimal weight of the coating material. Overall, more MP and MO materials react with LiOH than with LiCO. Specifically, MPs exhibit better reactivity to both Li residues, whereas MOs react more with LiOH. The reaction products, such as Li-containing phosphates or oxides, are also obtained to identify the phases on the surface of a cathode after coating. On the basis of the Pareto-front analysis, PO could be an optimal material for the reaction with both Li residuals. Finally, the reactivity of the coating materials containing 3d/4d transition metal elements is better than that of materials containing other types of elements.

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Section: Resultsmentioning

confidence: 99%

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Min

Seo

Choi

et al. 2017

ACS Appl. Mater. Interfaces

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“…Beyond biological concerns, phosphate adsorption on metal oxides is critical to investigate, since industrial LCO surface coatings incorporate phosphorus as the amorphous LiPON, or as an ordered metal phosphate such as AlPO 4 . It has been demonstrated that the functional properties and chemical behavior of LCO nanoparticles improve with these surface adsorbed coating layers, as the coating can enhance directed ionic transfer, act as a scavenger for HF released from solid state electrolytes, and act as a chemically stable barrier to protect the LCO surface from attack in aqueous environments. − …”

Section: Introductionmentioning

confidence: 99%

Ab InitioAtomistic Thermodynamics Study of the (001) Surface of LiCoO₂in a Water Environment and Implications for Reactivity under Ambient Conditions

et al. 2017

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We use GGA + U methodology to model the bulk and surface structure of varying stoichiometries of the (001) surface of LiCoO2. The DFT energies obtained for these surface-slab models are used for two thermodynamic analyses to assess the relative stabilities of different surface configurations, including hydroxylation. In the first approach, surface free energies are calculated within a thermodynamic framework, and the second approach is a surface-solvent ion exchange model. We find that, for both models, the −CoO–H1/2 surface is the most stable structure near the O-rich limit, which corresponds to ambient conditions. We find that surfaces terminated with Li are higher in energy, and we go on to show that H and Li behave differently on the (001) LiCoO2 surface. The optimized geometries show that terminal Li and H occupy nonequivalent surface sites. In terms of electronic structure, Li and H terminations exhibit distinct bandgap characters, and there is also a distinctive distribution of charge at the surface. We go on to probe how the variable Li and H terminations affect reactivity, as probed through phosphate adsorption studies.

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“…Among them, surface coating is considered to be the most effective method without the sacrifice of specific capacity. There are many coatings, such as binary oxides (e.g., Al 2 O 3 , , ZnO, , ZrO 2 , , MgO, SnO 2 , and TiO 2 , ), metal phosphates (e.g., AlPO 4 ), and metal fluorides (e.g., LiF , and MgF). ZnO has been recognized to be a proper material for improving the cycling stability of layered LiCoO 2 cathodes at high cutoff voltages. , In a previous study, Fang et al .…”

Section: Introductionmentioning

confidence: 99%

Improved Electrochemical Performance of LiCoO₂ Electrodes with ZnO Coating by Radio Frequency Magnetron Sputtering

Dai

Wang

et al. 2014

ACS Appl. Mater. Interfaces

110

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Surface modification of LiCoO2 is an effective method to improve its energy density and elongate its cycle life in an extended operation voltage window. In this study, ZnO was directly coated on as-prepared LiCoO2 composite electrodes via radio frequency (RF) magnetron sputtering. ZnO is not only coated on the electrode as thin film but also diffuses through the whole electrode due to the intrinsic porosity of the composite electrode and the high diffusivity of the deposited species. It was found that ZnO coating can significantly improve the cycling performance and the rate capability of the LiCoO2 electrodes in the voltage range of 3.0-4.5 V. The sample with an optimum coating thickness of 17 nm exhibits an initial discharge capacity of 191 mAh g(-1) at 0.2 C, and the capacity retention is 81% after 200 cycles. It also delivers superior rate performance with a reversible capacity of 106 mAh g(-1) at 10 C. The enhanced cycling performance and rate capability are attributed to the stabilized phase structure and improved lithium ion diffusion coefficient induced by ZnO coating as evidenced by X-ray diffraction, cyclic voltammetry, respectively.

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Effect of P₂O₅ and AlPO₄ Coating on LiCoO₂ Cathode Material.

Cited by 6 publications

References 1 publication

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Ab InitioAtomistic Thermodynamics Study of the (001) Surface of LiCoO₂in a Water Environment and Implications for Reactivity under Ambient Conditions

Improved Electrochemical Performance of LiCoO₂ Electrodes with ZnO Coating by Radio Frequency Magnetron Sputtering

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Effect of P2O5 and AlPO4 Coating on LiCoO2 Cathode Material.

Cited by 6 publications

References 1 publication

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes

Ab InitioAtomistic Thermodynamics Study of the (001) Surface of LiCoO2in a Water Environment and Implications for Reactivity under Ambient Conditions

Improved Electrochemical Performance of LiCoO2 Electrodes with ZnO Coating by Radio Frequency Magnetron Sputtering

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Product

Resources

About

Effect of P₂O₅ and AlPO₄ Coating on LiCoO₂ Cathode Material.

Ab InitioAtomistic Thermodynamics Study of the (001) Surface of LiCoO₂in a Water Environment and Implications for Reactivity under Ambient Conditions

Improved Electrochemical Performance of LiCoO₂ Electrodes with ZnO Coating by Radio Frequency Magnetron Sputtering