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Suppressing the charge-ordering transition in $LiMn_2O_4$ through substitution of Li by Mg

Basu, Rajiv and Seshadri, Ram (2000) Suppressing the charge-ordering transition in $LiMn_2O_4$ through substitution of Li by Mg. In: Journal of Material Chemistry, 10 (2). pp. 507-510.

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The important electrode material $LiMn_2O_4$undergoes a first order structural phase transition near room temperature. This transition, known to affect electrode characteristics, was long thought to result from the Jahn–Teller nature of Mn(III). However, Rodríguez-Carvajal and coworkers have recently established that with half-integral charge on Mn, what actually takes place at the transition is the crystallization of holes and electrons (charge ordering) in the crystal structure. Since the tendency to charge ordering is suppressed when charges on ions are not simple fractions, we have substituted Mg for Li to take Mn away from an average valence of 3.5. The transition is suppressed with as little as 4 atom% of Mg substitution for Li. The results suggest that the charge-ordering transition and Jahn–Teller distortions of the $Mn^{III}O_6$ octahedra are distinct phenomena

Item Type: Journal Article
Publication: Journal of Material Chemistry
Publisher: Royal Society of Chemistry
Additional Information: Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 18 Aug 2008
Last Modified: 19 Sep 2010 04:49
URI: http://eprints.iisc.ac.in/id/eprint/15630

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