High Temperature Co-doped LiMn2O4-Based Spinels. Structural, Electrical, and Electrochemical Characterization Full article
Journal |
Chemistry of Materials
ISSN: 0897-4756 , E-ISSN: 1520-5002 |
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Output data | Year: 2002, Volume: 14, Number: 4, Pages: 1598-1605 Pages count : 8 DOI: 10.1021/cm011219v | ||||||
Tags | MAGNETIC-PROPERTIES; Li; TRANSITION; CATHODE; OXYGEN; STOICHIOMETRY; CONDUCTION; INSERTION; LiCoMnO4Mg | ||||||
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Abstract:
High-temperature cubic spinels were obtained by thermal treatment at 1100 °C of the corresponding LiCoyMn2-yO4 (0 ≤ y ≤ 1) spinels. The samples were characterized by X-ray powder diffraction, thermogravimetric analysis, electron paramagnetic resonance (EPR) spectroscopy, and electrical and electrochemical measurements. The lattice parameter of the new phases in the 0.3 < y ≤ 1 range is larger compared to the starting ones. The EPR spectra of the new compounds are also different from the starting ones. The electrical conductivity of the new phases depends on the Co content. For y > 0.65 the sharp increase in conductivity observed is associated with a change in electron hopping from Mn3+/Mn4+ ions to Co2+/Co3+ ones. At high temperatures, the conductivity is explained in terms of phonon-assisted polaron hopping among either Mn3+/Mn4+ or Co2+/Co3+ nearest neighbors. At low temperatures electron hopping beyond the nearest neighbors accounts for the conductivity. The electrochemical behavior of the new compounds as positive electrodes was analyzed. The discharge curves show both the 4 and 5 V plateau due to the Mn4+/Mn3+ and Co4+/Co3+ reduction, respectively. Differences in electrochemical characteristics compared to the starting samples are found. From electrochemical and thermogravimetric measurements, the oxidation states of the transition metal ions and the chemical composition of the high-temperature samples are estimated.
Cite:
Mandal S.
, Rojas R.M.
, Amarilla J.M.
, Calle P.
, Kosova N.V.
, Anufrienko V.F.
, Rojo J.M.
High Temperature Co-doped LiMn2O4-Based Spinels. Structural, Electrical, and Electrochemical Characterization
Chemistry of Materials. 2002. V.14. N4. P.1598-1605. DOI: 10.1021/cm011219v WOS Scopus РИНЦ
High Temperature Co-doped LiMn2O4-Based Spinels. Structural, Electrical, and Electrochemical Characterization
Chemistry of Materials. 2002. V.14. N4. P.1598-1605. DOI: 10.1021/cm011219v WOS Scopus РИНЦ
Dates:
Submitted: | Aug 8, 2001 |
Published print: | Apr 1, 2002 |
Identifiers:
Web of science | WOS:000175028700022 |
Scopus | 2-s2.0-0036123728 |
Elibrary | 16940867 |
Chemical Abstracts | 2002:229773 |
Chemical Abstracts (print) | 136:349555 |
OpenAlex | W2020980135 |