Solid-state chemistry shuffling of alkali ions toward new layered oxide materials
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Date
2024-01-09
Journal Title
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Publisher
American Chemical Society
Abstract
Alkali transition-metal layered compounds usually contain only one type of alkali cation between the edge-shared octahedra layers. Herein, the ternary phase diagram A2Ni2TeO6 (A = Li, Na, K) was explored through solid-state synthesis and new alkali-mixed compositions showing alternation of distinct alkali layers are obtained. Such intergrowth structures are synthesized either by a single high-temperature treatment from raw chemicals or through reaction between layered precursors, the latter involving a solid-state process triggered at moderate temperatures. The in-depth characterization of the multiple cationic orderings is performed by combining powder diffraction techniques (X-rays and neutrons), high-resolution transmission electron microscopy, and solid-state NMR spectroscopy. In addition to the Ni/Te honeycomb ordering, alternation of lithium layers with sodium or potassium layers is observed for compositions (Li/Na)2Ni2TeO6 or (Li/K)2Ni2TeO6, respectively. Crystal structure solving was achieved by stacking building blocks of the respective single alkali layered oxides and unveiled a complex out-of-plane ordering of honeycomb layers. Moreover, a solid-state reaction between Li2Ni2TeO6 and NaKNi2TeO6 enables preparation of the new phase Li∼1Na∼0.5K∼0.5Ni2TeO6, a unique example containing up to three alkali cations and exhibiting a more complex stacking with sodium and potassium cations occupying the same layer. This investigation confirms that the chemical versatility of layered alkali transition-metal compounds could also occur on the alkali layer. Following the research methodology described here, we revisit the crystal chemistry of alkali transition-metal layered materials by exploring alkali ion substitutions previously thought infeasible, in order to find new alkali-mixed compositions. © 2024 American Chemical Society.
Description
Keywords
Alkali metals, Alkali metal compounds, Lithium, Oxide minerals, Crystal structure, Sodium, Potassium, Cations, Layers
Citation
Mpanga, E. M., Wernert, R., Fauth, F., Suard, E., Avdeev, M., Fraisse, B., Camacho, P. S., Carlier, D., Lebedev, O., Cassidy, S. J., Rousse, G., & Berthelot, R. (2024). Solid-state chemistry shuffling of alkali ions toward new layered oxide materials. Chemistry of Materials, 36(2), 892-900. doi:10.1021/acs.chemmater.3c02749