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Preparation and electrochemical properties of high-voltage cathode materials, LiMyNi0.5-yMn1.5O4 (M = Fe, Cu, Al, Mg; y=0.0-0.4)
被引:168
作者:
Fey, GTK
[1
]
Lu, CZ
[1
]
Kumar, TP
[1
]
机构:
[1] Natl Cent Univ, Dept Chem & Mat Engn, Chungli 32054, Taiwan
关键词:
multiple substitution;
cathode materials;
LiMn2O4;
spinel cathode;
lithium battery;
D O I:
10.1016/S0378-7753(03)00010-7
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
Solid-state synthesized LiNi0.5-yMyMn1.5O4 spinels, where M - Fe, Mg, Al, or Cu, and y = 0.0-0.4, have been studied as high-voltage cathode materials. Powder X-ray diffraction studies showed that all the substituents displayed a propensity for the 8a tetrahedral site at high concentrations. Cyclic voltammetric studies showed electrochemical activity around 4 V as well as above 4.4 V. While the 4-V activity was related solely to the Mn4+/Mn3+ couple, the 5-V activity was due to the redox reactions of Ni and the other transition metal ions. The cosubstituents reduced the 5-V capacity and shifted the redox potentials in the 5-V region to higher values. At high concentrations, the cosubstituents tended to occupy the 8a sites, which may lead to a blockage of lithium transport during the charge-discharge processes. LiNi0.4Fe0.1Mn1.5O4 registered the best performance with a first-cycle capacity of 117 mAh/g and 78% capacity retention over 60 cycles. Electrochemical impedance spectroscopic studies showed a decrease in the charge transfer resistance at high deintercalation levels. (C) 2003 Elsevier Science B.V. All rights reserved.
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页码:332 / 345
页数:14
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