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Title: Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F) as cathode materials for lithium ion battery from atomistic simulation

Abstract

Lithium transition metal fluorophosphates (Li{sub 2}MPO{sub 4}F, M: Co and Ni) have been investigated from atomistic simulation. In order to predict the characteristics of these materials as cathode materials for lithium ion batteries, structural property, defect chemistry, and Li{sup +} ion transportation property are characterized. The core–shell model with empirical force fields is employed to reproduce the unit-cell parameters of crystal structure, which are in good agreement with the experimental data. In addition, the formation energies of intrinsic defects (Frenkel and antisite) are determined by energetics calculation. From migration energy calculations, it is found that these flurophosphates have a 3D Li{sup +} ion diffusion network forecasting good Li{sup +} ion conducting performances. Accordingly, we expect that this study provides an atomic scale insight as cathode materials for lithium ion batteries. - Graphical abstract: Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F). Display Omitted - Highlights: • Lithium transition metal fluorophosphates (Li{sub 2}MPO{sub 4}F, M: Co and Ni) are investigated from classical atomistic simulation. • The unit-cell parameters from experimental studies are reproduced by the core–shell model. • Li{sup +} ion conducting Li{sub 2}MPO{sub 4}F has a 3D Li{sup +} ion diffusion network. • It is predicted thatmore » Li/Co or Li/Ni antisite defects are well-formed at a substantial concentration level.« less

Authors:
;
Publication Date:
OSTI Identifier:
22274056
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 204; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; CATHODES; CRYSTAL STRUCTURE; DEFECTS; DIFFUSION; ELECTRIC BATTERIES; FORMATION HEAT; IONIC CONDUCTIVITY; LITHIUM; LITHIUM IONS; MIGRATION; SIMULATION; TRANSITION ELEMENTS

Citation Formats

Lee, Sanghun, E-mail: sh0129.lee@samsung.com, and Park, Sung Soo, E-mail: sung.s.park@samsung.com. Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F) as cathode materials for lithium ion battery from atomistic simulation. United States: N. p., 2013. Web. doi:10.1016/J.JSSC.2013.06.003.
Lee, Sanghun, E-mail: sh0129.lee@samsung.com, & Park, Sung Soo, E-mail: sung.s.park@samsung.com. Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F) as cathode materials for lithium ion battery from atomistic simulation. United States. doi:10.1016/J.JSSC.2013.06.003.
Lee, Sanghun, E-mail: sh0129.lee@samsung.com, and Park, Sung Soo, E-mail: sung.s.park@samsung.com. Thu . "Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F) as cathode materials for lithium ion battery from atomistic simulation". United States. doi:10.1016/J.JSSC.2013.06.003.
@article{osti_22274056,
title = {Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F) as cathode materials for lithium ion battery from atomistic simulation},
author = {Lee, Sanghun, E-mail: sh0129.lee@samsung.com and Park, Sung Soo, E-mail: sung.s.park@samsung.com},
abstractNote = {Lithium transition metal fluorophosphates (Li{sub 2}MPO{sub 4}F, M: Co and Ni) have been investigated from atomistic simulation. In order to predict the characteristics of these materials as cathode materials for lithium ion batteries, structural property, defect chemistry, and Li{sup +} ion transportation property are characterized. The core–shell model with empirical force fields is employed to reproduce the unit-cell parameters of crystal structure, which are in good agreement with the experimental data. In addition, the formation energies of intrinsic defects (Frenkel and antisite) are determined by energetics calculation. From migration energy calculations, it is found that these flurophosphates have a 3D Li{sup +} ion diffusion network forecasting good Li{sup +} ion conducting performances. Accordingly, we expect that this study provides an atomic scale insight as cathode materials for lithium ion batteries. - Graphical abstract: Lithium transition metal fluorophosphates (Li{sub 2}CoPO{sub 4}F and Li{sub 2}NiPO{sub 4}F). Display Omitted - Highlights: • Lithium transition metal fluorophosphates (Li{sub 2}MPO{sub 4}F, M: Co and Ni) are investigated from classical atomistic simulation. • The unit-cell parameters from experimental studies are reproduced by the core–shell model. • Li{sup +} ion conducting Li{sub 2}MPO{sub 4}F has a 3D Li{sup +} ion diffusion network. • It is predicted that Li/Co or Li/Ni antisite defects are well-formed at a substantial concentration level.},
doi = {10.1016/J.JSSC.2013.06.003},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 204,
place = {United States},
year = {Thu Aug 15 00:00:00 EDT 2013},
month = {Thu Aug 15 00:00:00 EDT 2013}
}
  • Layered lithium ion battery cathode materials have been extensively investigated, of which layered–layered compositesxLi 2MnO 3·(1 -x)LiMO 2(M = Mn, Co, Ni) are of particular interest, owing to their high energy density.
  • The effect of Li{sub 4}Ti{sub 5}O{sub 12} (LTO) coating amount on the electrochemical cycling behavior of the LiCoO{sub 2} cathode was investigated at the high upper voltage limit of 4.5 V. Li{sub 4}Ti{sub 5}O{sub 12} ({<=}5 wt.%) is not incorporated into the host structure and leads to formation of uniform coating. The cycling performance of LiCoO{sub 2} cathode is related with the amount of Li{sub 4}Ti{sub 5}O{sub 12} coating. The initial capacity of the LTO-coated LiCoO{sub 2} decreased with increasing Li{sub 4}Ti{sub 5}O{sub 12} coating amount but showed enhanced cycling properties, compared to those of pristine material. The 3 wt.%more » LTO-coated LiCoO{sub 2} has the best electrochemical performance, showing capacity retention of 97.3% between 2.5 V and 4.3 V and 85.1% between 2.5 V and 4.5 V after 40 cycles. The coulomb efficiency shows that the surface coating of Li{sub 4}Ti{sub 5}O{sub 12} is beneficial to the reversible intercalation/de-intercalation of Li{sup +}. LTO-coated LiCoO{sub 2} provides good prospects for practical application of lithium secondary batteries free from safety issues.« less
  • Lithium has been extracted both electrochemically and chemically from the defect antifluorite-type structure, Li{sub 5}FeO{sub 4} (5Li{sub 2}O {center_dot} Fe{sub 2}O{sub 3}). The electrochemical data show that four lithium ions can be removed from Li{sub 5}FeO{sub 4} between 3.5 and 4.5 V. vs Li{sup 0}. X-ray absorption spectroscopy (XAS) data of electrochemically delithiated samples show evidence of some Fe{sup 3+} to Fe{sup 4+} oxidation during the initial charge. On the other hand, XAS data of chemically delithiated samples show no evidence of Fe{sup 3+} to Fe{sup 4+} oxidation, but rather a change in coordination of the Fe{sup 3+} ions frommore » tetrahedral to octahedral coordination, suggesting that lithium extraction from Li{sub 5}FeO{sub 4} is accompanied predominantly by the release of oxygen, the net loss being lithia (Li{sub 2}O); the residual lithium-iron-oxide product has a Fe{sub 2}O{sub 3}-rich composition. The high lithium content in Li{sub 5}FeO{sub 4} renders it an attractive cathode precursor for loading the graphite (C{sub 6}) anode of lithium-ion electrochemical cells with sufficient lithium to enable the discharge of a charged component in the parent cathode, Li{sub 1.2}V{sub 3}O{sub 8}, as well as the residual Fe{sub 2}O{sub 3}-rich component. The electrochemical behavior of C{sub 6}/Li{sub 5}FeO{sub 4}?Li{sub 1/2}V{sub 3}O{sub 8} lithium-ion cells is compared to C{sub 6}/Li{sub 2}MnO{sub 3}?Li{sub 1.2}V{sub 3}O{sub 8} cells containing a layered Li{sub 2}MnO{sub 3} (Li{sub 2}O {center_dot} MnO{sub 2}) cathode precursor with a lower Li{sub 2}O content, from which lithia can be extracted at higher potentials, typically >4 V vs metallic lithium. The ability to remove Li{sub 2}O electrochemically from metal oxide host structures with a high lithium content, such as Li{sub 5}FeO{sub 4}, has implications for Li-air cells.« less
  • Increasing lithium content is shown to be a successful strategy for designing new cathode materials. In layered LixNi2-4x/3Sb(x/3)O(2) (x = 1.00-1.15), lithium excess improves both discharge capacity and capacity retention at 1C. Structural studies reveal a complex nanostructure pattern of Li-Sb and Ni-Sb ordering where the interface between these domains forms the correct local configuration for good lithium mobility. The <1 nm Li-Sb stripe domains and their interfaces thereby effectively act as nanohighways for lithium diffusion.
  • Increasing lithium content is shown to be a successful strategy for designing new cathode materials. In layered Li xNi 2–4x/3Sb x/3O 2 (x = 1.00–1.15), lithium excess improves both discharge capacity and capacity retention at 1C. Structural studies disclose a complex nanostructure pattern of Li–Sb and Ni–Sb ordering where the interface between these domains forms the correct local configuration for good lithium mobility. The <1 nm Li–Sb stripe domains and their interfaces thereby effectively act as nanohighways for lithium diffusion.
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