Rationalizing the alkali ions distribution along the honeycomb layered (Li,Na)2SnO3 pseudo solid solution

Abstract

Alkali-rich layered oxides Li2SnO3 and Na2SnO3 are isostructural, but no alkali-mixed compositions have been reported so far. While the thermodynamic stability of such mixed compositions is predicted by DFT calculations mainly for the sodium-rich side, single-phase compounds Li2-xNaxSnO3 were successfully obtained in the whole composition range (0 ≤ x ≤ 2) by conventional solid-state synthesis thanks to a quenching procedure at the end of the heat treatment. From Li2SnO3 to Na2SnO2, the evolution of the cell parameters and the DFT calculations demonstrate that the lithium-to-sodium substitution occurs firstly inside the alkali layer up to Li0.5Na1.5SnO3 and then in the honeycomb layer.