Spectral, magnetic and electrochemical studies of layered manganese oxides with P2 and O2 structure

K. M. Shaju; K. V. Ramanujachary; S. E. Lofland; G. V. Subba Rao; B. V.R. Chowdari

doi:10.1039/b301043k

Spectral, magnetic and electrochemical studies of layered manganese oxides with P2 and O2 structure

K. M. Shaju, K. V. Ramanujachary, S. E. Lofland, G. V. Subba Rao, B. V.R. Chowdari

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Abstract

X-Ray photoelectron spectroscopy (XPS), infrared spectroscopy and magnetic susceptibility studies were performed on layered O2-phase compounds, Li _2/3(Ni_1/3Mn_2/3)O₂, Li _(2/3)+x(Ni_1/3Mn_2/3)O², Li _2/3(Co_0.15Mn_0.85)O₂ and Li _(2/3)+x(Co_0.15Mn_0.85)O₂ and their respective P2 phases, Na_2/3(Ni_1/3Mn_2/3)O ₂ and Na_2/3(Co_0.15Mn_0.85)O ₂. The observed electrochemical performance was correlated with the oxidation states of the M ions (M = Mn, Ni, Co). Li_(2/3)+x(Ni _1/3Mn_2/3)O₂ and Li_(2/3)+x(Co _0.15Mn_0.85)O₂ show significant improvement in their first-charge capacity over Li_2/3(Ni_1/3Mn _2/3)O₂ and Li_2/3(Co_0.15Mn _0.85)O₂ when used as cathodes vs. Li. Chemical analysis and XPS data indicate that the incorporation of x ∼ 1/3 in the above two compounds is accompanied by the reduction of a corresponding amount of Mn ⁴⁺ to Mn³⁺ ions in the lattice. The magnetic moments obtained in the paramagnetic region are in fair agreement with the oxidation state of the ions derived from the XPS data for the Ni-system but show deviations for the Co-system. Below 100 K, weak ferrimagnetic ordering is observed in Li_(2/3)+x(Ni_1/3Mn_2/3)O₂ and Li_(2/3)+x(Co_0.15Mn_0.85)O₂.

Original language	English (US)
Pages (from-to)	2633-2640
Number of pages	8
Journal	Journal of Materials Chemistry
Volume	13
Issue number	10
DOIs	https://doi.org/10.1039/b301043k
State	Published - Oct 2003

All Science Journal Classification (ASJC) codes

General Chemistry
Materials Chemistry

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10.1039/b301043k

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@article{0fa542075d504996b71b7d7cc9e5218f,

title = "Spectral, magnetic and electrochemical studies of layered manganese oxides with P2 and O2 structure",

abstract = "X-Ray photoelectron spectroscopy (XPS), infrared spectroscopy and magnetic susceptibility studies were performed on layered O2-phase compounds, Li 2/3(Ni1/3Mn2/3)O2, Li (2/3)+x(Ni1/3Mn2/3)O2, Li 2/3(Co0.15Mn0.85)O2 and Li (2/3)+x(Co0.15Mn0.85)O2 and their respective P2 phases, Na2/3(Ni1/3Mn2/3)O 2 and Na2/3(Co0.15Mn0.85)O 2. The observed electrochemical performance was correlated with the oxidation states of the M ions (M = Mn, Ni, Co). Li(2/3)+x(Ni 1/3Mn2/3)O2 and Li(2/3)+x(Co 0.15Mn0.85)O2 show significant improvement in their first-charge capacity over Li2/3(Ni1/3Mn 2/3)O2 and Li2/3(Co0.15Mn 0.85)O2 when used as cathodes vs. Li. Chemical analysis and XPS data indicate that the incorporation of x ∼ 1/3 in the above two compounds is accompanied by the reduction of a corresponding amount of Mn 4+ to Mn3+ ions in the lattice. The magnetic moments obtained in the paramagnetic region are in fair agreement with the oxidation state of the ions derived from the XPS data for the Ni-system but show deviations for the Co-system. Below 100 K, weak ferrimagnetic ordering is observed in Li(2/3)+x(Ni1/3Mn2/3)O2 and Li(2/3)+x(Co0.15Mn0.85)O2.",

author = "Shaju, {K. M.} and Ramanujachary, {K. V.} and Lofland, {S. E.} and {Subba Rao}, {G. V.} and Chowdari, {B. V.R.}",

year = "2003",

month = oct,

doi = "10.1039/b301043k",

language = "English (US)",

volume = "13",

pages = "2633--2640",

journal = "Journal of Materials Chemistry",

issn = "0959-9428",

publisher = "Royal Society of Chemistry",

number = "10",

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TY - JOUR

T1 - Spectral, magnetic and electrochemical studies of layered manganese oxides with P2 and O2 structure

AU - Shaju, K. M.

AU - Ramanujachary, K. V.

AU - Lofland, S. E.

AU - Subba Rao, G. V.

AU - Chowdari, B. V.R.

PY - 2003/10

Y1 - 2003/10

N2 - X-Ray photoelectron spectroscopy (XPS), infrared spectroscopy and magnetic susceptibility studies were performed on layered O2-phase compounds, Li 2/3(Ni1/3Mn2/3)O2, Li (2/3)+x(Ni1/3Mn2/3)O2, Li 2/3(Co0.15Mn0.85)O2 and Li (2/3)+x(Co0.15Mn0.85)O2 and their respective P2 phases, Na2/3(Ni1/3Mn2/3)O 2 and Na2/3(Co0.15Mn0.85)O 2. The observed electrochemical performance was correlated with the oxidation states of the M ions (M = Mn, Ni, Co). Li(2/3)+x(Ni 1/3Mn2/3)O2 and Li(2/3)+x(Co 0.15Mn0.85)O2 show significant improvement in their first-charge capacity over Li2/3(Ni1/3Mn 2/3)O2 and Li2/3(Co0.15Mn 0.85)O2 when used as cathodes vs. Li. Chemical analysis and XPS data indicate that the incorporation of x ∼ 1/3 in the above two compounds is accompanied by the reduction of a corresponding amount of Mn 4+ to Mn3+ ions in the lattice. The magnetic moments obtained in the paramagnetic region are in fair agreement with the oxidation state of the ions derived from the XPS data for the Ni-system but show deviations for the Co-system. Below 100 K, weak ferrimagnetic ordering is observed in Li(2/3)+x(Ni1/3Mn2/3)O2 and Li(2/3)+x(Co0.15Mn0.85)O2.

AB - X-Ray photoelectron spectroscopy (XPS), infrared spectroscopy and magnetic susceptibility studies were performed on layered O2-phase compounds, Li 2/3(Ni1/3Mn2/3)O2, Li (2/3)+x(Ni1/3Mn2/3)O2, Li 2/3(Co0.15Mn0.85)O2 and Li (2/3)+x(Co0.15Mn0.85)O2 and their respective P2 phases, Na2/3(Ni1/3Mn2/3)O 2 and Na2/3(Co0.15Mn0.85)O 2. The observed electrochemical performance was correlated with the oxidation states of the M ions (M = Mn, Ni, Co). Li(2/3)+x(Ni 1/3Mn2/3)O2 and Li(2/3)+x(Co 0.15Mn0.85)O2 show significant improvement in their first-charge capacity over Li2/3(Ni1/3Mn 2/3)O2 and Li2/3(Co0.15Mn 0.85)O2 when used as cathodes vs. Li. Chemical analysis and XPS data indicate that the incorporation of x ∼ 1/3 in the above two compounds is accompanied by the reduction of a corresponding amount of Mn 4+ to Mn3+ ions in the lattice. The magnetic moments obtained in the paramagnetic region are in fair agreement with the oxidation state of the ions derived from the XPS data for the Ni-system but show deviations for the Co-system. Below 100 K, weak ferrimagnetic ordering is observed in Li(2/3)+x(Ni1/3Mn2/3)O2 and Li(2/3)+x(Co0.15Mn0.85)O2.

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U2 - 10.1039/b301043k

DO - 10.1039/b301043k

M3 - Article

AN - SCOPUS:0142186805

SN - 0959-9428

VL - 13

SP - 2633

EP - 2640

JO - Journal of Materials Chemistry

JF - Journal of Materials Chemistry

IS - 10

ER -

Spectral, magnetic and electrochemical studies of layered manganese oxides with P2 and O2 structure

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