DOE OSTI2020
Li2TiNi2O5 is Caswellsilverite-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NiO6 octahedra, edges with three TiO6 octahedra, edges with four LiO6 octahedra, and edges with five NiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Li–O bond distances ranging from 2.05–2.33 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four NiO6 octahedra, edges with four LiO6 octahedra, edges with four TiO6 octahedra, and edges with four NiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Li–O bond distances ranging from 2.05–2.16 Å. In the third Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent NiO6 octahedra, corners with four LiO6 octahedra, edges with two equivalent LiO6 octahedra, edges with three TiO6 octahedra, and edges with seven NiO6 octahedra. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Li–O bond distances ranging from 2.05–2.19 Å. In the fourth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four LiO6 octahedra, edges with two equivalent LiO6 octahedra, edges with three TiO6 octahedra, and edges with seven NiO6 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. There are a spread of Li–O bond distances ranging from 2.04–2.29 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NiO6 octahedra, edges with six LiO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are a spread of Ti–O bond distances ranging from 1.97–2.06 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NiO6 octahedra, edges with five NiO6 octahedra, and edges with seven LiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Ti–O bond distances ranging from 1.94–2.06 Å. There are four inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NiO6 octahedra, edges with two equivalent TiO6 octahedra, edges with four NiO6 octahedra, and edges with six LiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Ni–O bond distances ranging from 2.07–2.15 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four NiO6 octahedra, an edgeedge with one NiO6 octahedra, edges with four TiO6 octahedra, and edges with seven LiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Ni–O bond distances ranging from 2.06–2.10 Å. In the third Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NiO6 octahedra, edges with two equivalent TiO6 octahedra, edges with five LiO6 octahedra, and edges with five NiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–8°. There are a spread of Ni–O bond distances ranging from 2.08–2.14 Å. In the fourth Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four NiO6 octahedra, edges with three TiO6 octahedra, edges with four NiO6 octahedra, and edges with five LiO6 octahedra. The corner-sharing octahedra tilt angles range from 5–9°. There are a spread of Ni–O bond distances ranging from 2.06–2.13 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two Li1+, one Ti4+, and three Ni2+ atoms to form OLi2TiNi3 octahedra that share corners with six OLi3Ti2Ni octahedra and edges with twelve OLi2TiNi3 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the second O2- site, O2- is bonded to three Li1+, one Ti4+, and two Ni2+ atoms to form a mixture of edge and corner-sharing OLi3TiNi2 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. In the third O2- site, O2- is bonded to two Li1+, one Ti4+, and three Ni2+ atoms to form a mixture of edge and corner-sharing OLi2TiNi3 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. In the fourth O2- site, O2- is bonded to two Li1+, one Ti4+, and three Ni2+ atoms to form a mixture of edge and corner-sharing OLi2TiNi3 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. In the fifth O2- site, O2- is bonded to three Li1+, two Ti4+, and one Ni2+ atom to form a mixture of edge and corner-sharing OLi3Ti2Ni octahedra. The corner-sharing octahedra tilt angles range from 1–4°.