Crystal structure investigation of spinel‐type LiAlON with multiple atomic disorders

Abstract

Spinel‐type lithium aluminum oxynitride (LiAlON) contains atomic disorders at every crystallographic position, including vacancies, cation, and anion disorders. In this work, the crystal structure of spinel‐type LiAlON with multiple atomic disorders was systematically studied by first‐principles calculation, solid‐state NMR, and the Rietveld crystal structure refinement. The theoretical simulations demonstrate that the Li+ occupies octahedral positions and prefers to be far away from the N3− and cation vacancies in the crystal structure of LiAlON. A spinel‐type LiAlON compound with chemical formula of Li0.06Al2.72O3.77N0.23 was prepared by solid‐state reaction. The local structure of Li+ and Al3+ was probed by 7Li and 27Al solid‐state NMR technology. Combined with theoretical calculations and solid‐state NMR, the crystal structure of Li0.06Al2.72O3.77N0.23 was fully resolved by the Rietveld refinement. This work provides a deep understanding on the disordered crystal structure of the spinel‐type LiAlON solid solution.