Issue 2, 2004

The synthesis, characterization and electrochemical behavior of the layered LiNi0.4Mn0.4Co0.2O2 compound

Abstract

The mixed transition metal layered compound, LiNi0.4Mn0.4Co0.2O2, with the α-NaFeO2 layer structure has been synthesized and characterized. The optimum temperature of synthesis was found to be 800–900 °C. Rietveld refinement showed that cobalt suppresses transition metal ion migration into the Li sites whereas nickel promotes the migration. XPS analysis shows that the Co and about 20% of the Ni and Mn are in the 3+ oxidation state, while 80% of the Ni and Mn are in the 2+ and 4+ oxidation states, respectively. LiNi0.4Mn0.4Co0.2O2 shows Curie–Weiss paramagnetic behavior above 150 K, and the value of the Curie constant is consistent with the above oxidation states. In lithium electrochemical cells the composition LiNi0.4Mn0.4Co0.2O2 gave the highest reversible capacity among the studied compositions. It shows excellent rate capability, giving reversible capacities ranging from 180 to 155 mA h g−1 at current densities from 0.1 to 2.0 mA cm−2.

Graphical abstract: The synthesis, characterization and electrochemical behavior of the layered LiNi0.4Mn0.4Co0.2O2 compound

Article information

Article type
Paper
Submitted
14 aug 2003
Accepted
07 nov 2003
First published
10 dec 2003

J. Mater. Chem., 2004,14, 214-220

The synthesis, characterization and electrochemical behavior of the layered LiNi0.4Mn0.4Co0.2O2 compound

J. K. Ngala, N. A. Chernova, M. Ma, M. Mamak, P. Y. Zavalij and M. S. Whittingham, J. Mater. Chem., 2004, 14, 214 DOI: 10.1039/B309834F

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