Fast Lithium Ion Diffusion in the Ternary Layered Nitridometalate LiNiN

The structure, Li⁺ diffusion dynamics, and magnetic properties of the layered nitridonickelate(II), LiNiN, have been investigated by powder X-ray diffraction, ⁷Li solid-state NMR, and SQUID magnetometry and compared and contrasted with those of the Li⁺ fast ion conductor, Li₃N. The replacement of Li⁺ by Ni²⁺ with concomitant generation of Li⁺ vacancies has profound effects on ionic diffusion and electronic properties. The nitridonickelate, akin to its binary parent, displays rapid Li⁺ ion diffusion but, by contrast, the diffusion process is confined only to the Li?N planes. Further, replacement of Li by Ni leads to a transition from semiconducting to metallic behavior, likely mediated through the creation of infinite, 1D Ni?N chains of increased covalency.