Spinel-rock salt transformation in LiCoMnO4-δ

Nik Reeves-McLaren, Joanne Sharp, Héctor Beltrán-Mir, W. Mark Rainforth, Anthony R. West

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

The transformation on heating LiCoMnO4, with a spinel structure, to LiCoMnO3, with a cation-disordered rock salt structure, accompanied by loss of 25% of the oxygen, has been followed using a combination of diffraction, microscopy and spectroscopy techniques. The transformation does not proceed by a topotactic mechanism, even though the spinel and rock salt phases have a similar, cubic close-packed oxygen sublattice. Instead, the transformation passes through two stages involving, first, precipitation of Li2MnO3, leaving behind a Li-deficient, Co-rich non-stoichiometric spinel and, second, rehomogenization of the two-phase assemblage, accompanied by additional oxygen loss, to give the homogeneous rock salt final product; a combination of electron energy loss spectroscopy and X-ray absorption near edge structure analyses showed oxidation states of Co2+ and Mn3+ in LiCoMnO3. Subsolidus phase diagram determination of the Li2O-CoOx-MnOysystem has established the compositional extent of spinel solid solutions at approximately 500 C.

Original languageEnglish
Article number20140991
Number of pages20
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume472
Issue number2185
Early online date1 Jan 2016
DOIs
Publication statusPublished - 31 Jan 2016
Externally publishedYes

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