Lithium-sodium metazirconate solid solutions, Li2-xNaxZrO3 (0 ≤ x ≤ 2):: A hierarchical architecture

Solid solutions of lithium and sodium metazirconates, Li2-xNaxZrO3 (0 <= x <= 2), were prepared by coprecipitation. Then, samples were characterized by powder X-ray diffraction, small-angle X-ray scattering, transmission electron microscopy, solid-state nuclear magnetic resonance, and N-2 adsorption (BET). Results show that the solubility limits of sodium into Li2ZrO3 and lithium into Na2ZrO3 are definitely different. While the maximum amount of sodium that can be inserted into Li2-xNaxZrO3 is 0.2, the amount of soluble lithium into Na2-xLixZrO3 is 0.6. Furthermore, the analyses strongly suggest that Li2-xNaxZrO3 encloses Na2-xLixZrO3, as in a cherry model, and the internal phase is lithium enriched, as shown by the fractal dimension values. The core size is close to 10-20 nm, and the full particle is about 1 mu m. The outer shell presents some microporosity. Such a model is supported by kinetic and thermodynamic data.