DOE OSTI2020
Li4Ti3Fe2Cu3O16 is Spinel-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Li sites. In the first Li site, Li is bonded to four O atoms to form LiO4 tetrahedra that share corners with three equivalent FeO6 octahedra, corners with four TiO6 octahedra, and corners with five CuO6 octahedra. The corner-sharing octahedra tilt angles range from 54–63°. There is two shorter (1.93 Å) and two longer (1.98 Å) Li–O bond length. In the second Li site, Li is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are a spread of Li–O bond distances ranging from 1.82–2.07 Å. In the third Li site, Li is bonded to four O atoms to form distorted LiO4 tetrahedra that share a cornercorner with one CuO6 octahedra, corners with two equivalent TiO6 octahedra, corners with three equivalent FeO6 octahedra, an edgeedge with one TiO6 octahedra, and edges with two equivalent CuO6 octahedra. The corner-sharing octahedra tilt angles range from 60–63°. There are a spread of Li–O bond distances ranging from 1.81–1.95 Å. In the fourth Li site, Li is bonded to four O atoms to form LiO4 tetrahedra that share corners with three equivalent FeO6 octahedra, corners with four CuO6 octahedra, and corners with five TiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–65°. There are a spread of Li–O bond distances ranging from 1.95–1.99 Å. There are two inequivalent Ti sites. In the first Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four LiO4 tetrahedra, an edgeedge with one FeO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with two equivalent CuO6 octahedra. The corner-sharing octahedra tilt angles range from 51–52°. There are a spread of Ti–O bond distances ranging from 1.93–2.05 Å. In the second Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with three LiO4 tetrahedra, an edgeedge with one FeO6 octahedra, edges with four equivalent CuO6 octahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ti–O bond distances ranging from 1.91–2.06 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent CuO6 octahedra, corners with six LiO4 tetrahedra, an edgeedge with one CuO6 octahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Fe–O bond distances ranging from 1.99–2.17 Å. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four equivalent TiO6 octahedra, corners with three equivalent LiO4 tetrahedra, an edgeedge with one TiO6 octahedra, and edges with two equivalent CuO6 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Fe–O bond distances ranging from 1.99–2.13 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to six O atoms to form CuO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four LiO4 tetrahedra, an edgeedge with one FeO6 octahedra, and edges with four equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Cu–O bond distances ranging from 1.95–2.09 Å. In the second Cu site, Cu is bonded to six O atoms to form CuO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with three LiO4 tetrahedra, an edgeedge with one FeO6 octahedra, edges with two equivalent TiO6 octahedra, edges with two equivalent CuO6 octahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Cu–O bond distances ranging from 1.92–2.15 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to one Li, one Ti, one Fe, and one Cu atom. In the second O site, O is bonded to one Li, two equivalent Ti, and one Fe atom to form distorted OLiTi2Fe tetrahedra that share corners with four OLiTi2Cu tetrahedra and edges with two equivalent OLiTiFeCu tetrahedra. In the third O site, O is bonded in a rectangular see-saw-like geometry to one Li, two equivalent Ti, and one Cu atom. In the fourth O site, O is bonded to one Li, two equivalent Ti, and one Cu atom to form corner-sharing OLiTi2Cu tetrahedra. In the fifth O site, O is bonded to one Li, one Ti, and two equivalent Cu atoms to form corner-sharing OLiTiCu2 tetrahedra. In the sixth O site, O is bonded to one Li, one Ti, one Fe, and one Cu atom to form a mixture of distorted edge and corner-sharing OLiTiFeCu tetrahedra. In the seventh O site, O is bonded in a rectangular see-saw-like geometry to one Li, two equivalent Ti, and one Fe atom. In the eighth O site, O is bonded in a rectangular see-saw-like geometry to one Li, one Fe, and two equivalent Cu atoms. In the ninth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Li, one Ti, one Fe, and one Cu atom. In the tenth O site, O is bonded in a rectangular see-saw-like geometry to one Li, one Ti, and two equivalent Cu atoms. In the eleventh O site, O is bonded in a rectangular see-saw-like geometry to one Li, one Ti, one Fe, and one Cu atom. In the twelfth O site, O is bonded to one Li, one Fe, and two equivalent Cu atoms to form distorted corner-sharing OLiFeCu2 tetrahedra.