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Title: A Comparative Study on Structural Changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 During First Charge using in situ XRD

Abstract

A synchrotron based in situ XRD technique was used to investigate the structural changes of Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} as cathode material in lithium battery during first charge in comparison with Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}. The structural changes of these two cathode materials during first charge follow the similar trend as LiNiO{sub 2}: an expansion along the c-axis of the unit cell with contractions along the a- and b-axis during the early stage of charge and a major contraction along the c-axis with slight expansions along the a- and b-axis near the end of charge at high voltage limit. However, the degree of disorder in Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} is higher than in Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}, which in turn is higher than in LiNiO{sub 2}. More importantly, the structural stability of Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} is higher than Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}, which in turn is higher than LiNiO{sub 2}, as reflected in the suppression of hexagonal 3 (H3) phase with collapsed c-axis formed at the end of charge.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914183
Report Number(s):
BNL-78751-2007-JA
Journal ID: ISSN 1388-2481; TRN: US0801599
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Electrochem. Commun.; Journal Volume: 8; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CATHODES; CONTRACTION; LITHIUM; STABILITY; SYNCHROTRONS; X-RAY DIFFRACTION; national synchrotron light source

Citation Formats

Yoon,W., Chung, K., McBreen, J., and Yang, X. A Comparative Study on Structural Changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 During First Charge using in situ XRD. United States: N. p., 2006. Web. doi:10.1016/j.elecom.2006.06.005.
Yoon,W., Chung, K., McBreen, J., & Yang, X. A Comparative Study on Structural Changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 During First Charge using in situ XRD. United States. doi:10.1016/j.elecom.2006.06.005.
Yoon,W., Chung, K., McBreen, J., and Yang, X. Sun . "A Comparative Study on Structural Changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 During First Charge using in situ XRD". United States. doi:10.1016/j.elecom.2006.06.005.
@article{osti_914183,
title = {A Comparative Study on Structural Changes of LiCo1/3Ni1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 During First Charge using in situ XRD},
author = {Yoon,W. and Chung, K. and McBreen, J. and Yang, X.},
abstractNote = {A synchrotron based in situ XRD technique was used to investigate the structural changes of Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} as cathode material in lithium battery during first charge in comparison with Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}. The structural changes of these two cathode materials during first charge follow the similar trend as LiNiO{sub 2}: an expansion along the c-axis of the unit cell with contractions along the a- and b-axis during the early stage of charge and a major contraction along the c-axis with slight expansions along the a- and b-axis near the end of charge at high voltage limit. However, the degree of disorder in Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} is higher than in Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}, which in turn is higher than in LiNiO{sub 2}. More importantly, the structural stability of Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} is higher than Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}, which in turn is higher than LiNiO{sub 2}, as reflected in the suppression of hexagonal 3 (H3) phase with collapsed c-axis formed at the end of charge.},
doi = {10.1016/j.elecom.2006.06.005},
journal = {Electrochem. Commun.},
number = 8,
volume = 8,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • The structural changes of the composite cathode made by mixing spinel LiMn2O4 and layered LiNi1/3Co1/3Mn1/3O2 in 1:1 wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to {approx}5.2 V vs. Li/Li+, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the LiNi1/3Co1/3Mn1/3O2 component only. When the cell voltage reaches at {approx}4.0 V vs. Li/Li+, lithium extraction from the spinel LiMn2O4 component starts and becomes the majormore » contributor for the cell capacity due to the higher rate capability of LiMn2O4. When the voltage passed 4.3 V, the major structural changes are from the LiNi1/3Co1/3Mn1/3O2 component, while the LiMn2O4 component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5 V and 4.2 V, the structural changes are dominated by the spinel LiMn2O4 component, with much less changes in the layered LiNi1/3Co1/3Mn1/3O2 component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research.« less
  • Structural changes and their relationship with thermal stability of charged Li0.33Ni1/3Co1/3Mn1/3O2 cathode samples have been studied using time-resolved X-ray diffraction (TR-XRD) in a wide temperature from 25 to 600 C with and without the presence of electrolyte in comparison with Li0.27Ni0.8Co0.15Al0.05O2 cathodes. Unique phase transition behavior during heating is found for the Li0.33Ni1/3Co1/3Mn1/3O2 cathode samples: when no electrolyte is present, the initial layered structure changes first to a LiM2O4-type spinel, and then to a M3O4-type spinel and remains in this structure up to 600 C. For the Li0.33Ni1/3Co1/3Mn1/3O2 cathode sample with electrolyte, additional phase transition from the M3O4-type spinel tomore » the MO-type rock salt phase takes place from about 400 to 441 C together with the formation of metallic phase at about 460 C. The major difference between this type of phase transitions and that for Li0.27Ni0.8Co0.15Al0.05O2 in the presence of electrolyte is the delayed phase transition from the spinel-type to the rock salt-type phase by stretching the temperature range of spinel phases from about 20 to 140 C. This unique behavior is considered as the key factor of the better thermal stability of the Li1-xNi1/3Co1/3Mn1/3O2 cathode materials.« less
  • In situ hard X-ray absorption spectroscopy (XAS) at metal K-edges and soft XAS at O K-edge and metal L-edges have been carried out during the first charging process for the layered Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} cathode material. The metal K-edge XANES results show that the major charge compensation at the metal site during Li-ion deintercalation is achieved by the oxidation of Ni{sup 2+} ions, while the manganese ions and the cobalt ions remain mostly unchanged in the Mn{sup 4+} and Co{sup 3+} state. These conclusions are in good agreement with the results of the metal K-edge EXAFS data.more » Metal L-edge XAS results at different charge states in both the FY and PEY modes show that, unlike Mn and Co ions, Ni ions at the surface are oxidized to Ni{sup 3+} during charge, whereas Ni ions in the bulk are further oxidized to Ni{sup 4+} during charge. From the observation of O K-edge XAS results, we can conclude that a large portion of the charge compensation during Li-ion deintercalation is achieved in the oxygen site. By comparison to our earlier results on the Li{sub 1-x}Ni{sub 0.5}Mn{sub 0.5}O{sub 2} system, we attribute the active participation of oxygen in the redox process in Li{sub 1-x}Co{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} to be related to the presence of Co in this system.« less
  • No abstract prepared.
  • How the structural changes of each active material in mixed cathode systems take place at different charge-discharge rates is quite important in the application of the system in which the mixed cathode materials with different rate capabilities are formed into one composite electrode. Here we report the results of the real time structural change studies of mixed LiMn{sub 2}O{sub 4}-LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} composite cathode in a Li-ion cell by using in situ synchrotron-based time resolved x-ray diffraction (TR-XRD) technique. The layer structured component in the mixed composite cathode system shows less utilization at fast discharge rate (high powermore » mode) whereas the spinel structured component is fully utilized. This clearly demonstrates that the reduced capacity at fast discharge rate for this system is caused by the less utilization of the layer structured component. The real time monitoring of the structural behavior at various discharge rates is a great tool to design the best ratios of active materials with different rate capabilities in the mixed cathode systems for different applications.« less