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Title: Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material

Abstract

Li(Ni{sub 0.4}Co{sub 0.2-y}Al{sub y}Mn{sub 0.4})O{sub 2} with y=0.05 was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. The effect of the substitution was studied by in-situ X-ray absorption spectroscopy (XAS), utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range (1.0-4.7 V). XAS measurements were performed at different states-of-charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized towards Co{sup 4+} and Mn was found to be electrochemically inactive and remains as Mn{sup 4+}. Themore » EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Environmental Energy Technologies Division
OSTI Identifier:
984355
Report Number(s):
LBNL-3582E
TRN: US201015%%1112
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Electrochemical Society
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; ABSORPTION; ABSORPTION SPECTROSCOPY; ALUMINIUM; CATHODES; COBALT; COORDINATION NUMBER; ELECTROCHEMICAL CELLS; FINE STRUCTURE; SPECTRA; SYMMETRY; TRANSITION ELEMENTS; VALENCE

Citation Formats

Rumble, C., Conry, T.E., Doeff, Marca, Cairns, Elton J., Penner-Hahn, James. E., and Deb, Aniruddha. Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material. United States: N. p., 2010. Web. doi:10.1149/1.3494211.
Rumble, C., Conry, T.E., Doeff, Marca, Cairns, Elton J., Penner-Hahn, James. E., & Deb, Aniruddha. Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material. United States. doi:10.1149/1.3494211.
Rumble, C., Conry, T.E., Doeff, Marca, Cairns, Elton J., Penner-Hahn, James. E., and Deb, Aniruddha. 2010. "Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material". United States. doi:10.1149/1.3494211. https://www.osti.gov/servlets/purl/984355.
@article{osti_984355,
title = {Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material},
author = {Rumble, C. and Conry, T.E. and Doeff, Marca and Cairns, Elton J. and Penner-Hahn, James. E. and Deb, Aniruddha},
abstractNote = {Li(Ni{sub 0.4}Co{sub 0.2-y}Al{sub y}Mn{sub 0.4})O{sub 2} with y=0.05 was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. The effect of the substitution was studied by in-situ X-ray absorption spectroscopy (XAS), utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range (1.0-4.7 V). XAS measurements were performed at different states-of-charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized towards Co{sup 4+} and Mn was found to be electrochemically inactive and remains as Mn{sup 4+}. The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.},
doi = {10.1149/1.3494211},
journal = {Electrochemical Society},
number = ,
volume = ,
place = {United States},
year = 2010,
month = 2
}
  • Li(Ni{sub 0.4}Co{sub 0.15}Al{sub 0.05}Mn{sub 0.4})O{sub 2} was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. In situ X-ray absorption spectroscopy (XAS) was performed, utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range. (1.0-4.7 V) XAS measurements were performed at different states of charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extendedmore » X-ray absorption fine structure (EXAFS) region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized toward Co{sup 4+}, and Mn was found to be electrochemically inactive and remained as Mn{sup 4+}. The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O, and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.« less
  • The candidate cathode material Li{sub 2}MnSiO{sub 4} for lithium-ion cells was synthesized by an all-acetate precursor sol/gel method under a reducing atmosphere at 600, 700, and 800 C. The material prepared at 700 C was a pure phase and had the structural order of Li{sub 3}PO{sub 4} orthorhombic (S.G. Pmn2{sub 1}) phase. The temperature dependence of the molar magnetic susceptibility of Li{sub 2}MnSiO{sub 4} was found to be consistent with an antiferromagnetic material with a Nel temperature of 12 K. The calculated effective moment confirmed that the observed magnetic behavior involves Mn{sup 2+} ions in a high spin configuration inmore » tetrahedral sites. Scanning electron microscopy of Li{sub 2}MnSiO{sub 4} showed large aggregates (10 to 50 {micro}m) composed of nanosized particles (100-200 nm). The as-prepared material was almost electrochemically inactive despite the presence of 15 wt % carbon additive. The material was treated by carbon coating using cellulose carbon source precursor and particle size reduction using high-energy ball milling. In coin-cell tests, the carbon-coated and ball-milled materials yielded charge capacities of 190 and 172 mAh/g, respectively, under a current density of 10 mA/g. At present, the cationic mixing between Li{sup +} and Mn{sup 2+} ions in their mutual crystallographic sites is the main impediment to the achievement of the full theoretical capacity of Li{sub 2}MnSiO{sub 4} (333 mAh/g).« less