Results for “Li-Mn-Nb-O”

DOE OSTI2020

A Fluorination Method for Improving Cation-Disordered Rocksalt Cathode Performance

In Li-rich cation-disordered rocksalt oxide cathodes (DRX), partial fluorine substitution in the oxygen anion sublattice can increase the capacity contribution from transition-metal (TM) redox while reducing that from the less reversible oxygen redox. To date, limited fluorination substitution has been achieved by introducing LiF precursor during the solid-state synthesis. To take full advantage of the fluorination effect, however, a higher F content is desired. In the present study, the successful use of a fluorinated polymeric precursor is reported to increase the F solubility in DRX and the incorporation of F content up to 10–12.5 at% into the rocksalt lattice of a model Li-Mn-Nb-O (LMNO) system, largely exceeding the 7.5 at% limit achieved with LiF synthesis. Higher F content in the fluorinated-DRX (F-DRX) significantly improves electrochemical performance, with a reversible discharge capacity of ≈255 mAh g –1 achieved at 10 at% of F substitution. After 30 cycles, up to a 40% increase in capacity retention is achieved through the fluorination. Overall, the study demonstrates the feasibility of using a new and effective fluorination process to synthesize advanced DRX cathode materials.

25 ENERGY STORAGE↗

DOE OSTI2020

Materials Data on Li13Mn3Nb2O16 by Materials Project

Li13Nb2Mn3O16 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are ten inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two equivalent MnO6 octahedra, corners with three equivalent NbO6 octahedra, a cornercorner with one LiO4 tetrahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 38–75°. There are a spread of Li–O bond distances ranging from 1.83–1.99 Å. In the second Li1+ site, Li1+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.95–2.58 Å. In the third Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 1.92–2.42 Å. In the fourth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with three NbO6 octahedra, corners with three equivalent MnO6 octahedra, a cornercorner with one LiO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–71°. There are a spread of Li–O bond distances ranging from 1.90–2.03 Å. In the fifth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with two LiO4 tetrahedra, an edgeedge with one NbO6 octahedra, edges with two equivalent LiO6 octahedra, and edges with four equivalent MnO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Li–O bond distances ranging from 2.05–2.42 Å. In the sixth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 1.94–2.45 Å. In the seventh Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with three equivalent NbO6 octahedra, edges with two equivalent LiO6 octahedra, edges with four equivalent MnO6 octahedra, and a faceface with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. There are a spread of Li–O bond distances ranging from 2.04–2.34 Å. In the eighth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three equivalent NbO6 octahedra, corners with four MnO6 octahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–61°. There are a spread of Li–O bond distances ranging from 1.81–2.20 Å. In the ninth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.96–2.56 Å. In the tenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.94–2.31 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent MnO6 octahedra, corners with five LiO4 tetrahedra, an edgeedge with one MnO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 46–50°. There are a spread of Nb–O bond distances ranging from 1.97–2.07 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with three equivalent LiO6 octahedra, corners with four LiO4 tetrahedra, an edgeedge with one LiO6 octahedra, and edges with two equivalent MnO6 octahedra. The corner-sharing octahedra tilt angles range from 3–47°. There are a spread of Nb–O bond distances ranging from 1.93–2.18 Å. There are two inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with two LiO4 tetrahedra, an edgeedge with one NbO6 octahedra, edges with two equivalent MnO6 octahedra, and edges with four LiO6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Mn–O bond distances ranging from 1.97–2.31 Å. In the second Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with five LiO4 tetrahedra, an edgeedge with one NbO6 octahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Mn–O bond distances ranging from 1.89–2.23 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four Li1+, one Nb5+, and one Mn3+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four Li1+ and one Nb5+ atom. In the third O2- site, O2- is bonded in a 6-coordinate geometry to five Li1+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded to four Li1+, one Nb5+, and one Mn3+ atom to form OLi4MnNb octahedra that share a cornercorner with one OLi3Mn2 trigonal bipyramid, edges with four OLi4MnNb octahedra, and an edgeedge with one OLi3Mn2 trigonal bipyramid. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to four Li1+, one Nb5+, and one Mn3+ atom. In the sixth O2- site, O2- is bonded in a 7-coordinate geometry to five Li1+, one Nb5+, and one Mn3+ atom. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to five Li1+ and one Mn3+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to five Li1+ and two equivalent Mn3+ atoms. In the ninth O2- site, O2- is bonded to three Li1+, one Nb5+, and two equivalent Mn3+ atoms to form OLi3Mn2Nb octahedra that share corners with two equivalent OLi3Mn2 trigonal bipyramids and edges with four equivalent OLi4MnNb octahedra. In the tenth O2- site, O2- is bonded in a 6-coordinate geometry to three Li1+, one Nb5+, and two equivalent Mn3+ atoms. In the eleventh O2- site, O2- is bonded in a 7-coordinate geometry to six Li1+ and one Mn3+ atom. In the twelfth O2- site, O2- is bonded to three Li1+ and two equivalent Mn3+ atoms to form a mixture of distorted corner and edge-sharing OLi3Mn2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 74–88°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Li2MnNb3O8 by Materials Project

Li2Nb3MnO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with three equivalent LiO6 octahedra and corners with nine equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 51–59°. There is one shorter (1.97 Å) and three longer (1.99 Å) Li–O bond length. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with three equivalent LiO4 tetrahedra, corners with three equivalent MnO4 tetrahedra, and edges with six equivalent NbO6 octahedra. There are three shorter (2.15 Å) and three longer (2.20 Å) Li–O bond lengths. Nb4+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent LiO4 tetrahedra, corners with three equivalent MnO4 tetrahedra, edges with two equivalent LiO6 octahedra, and edges with four equivalent NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 2.05–2.19 Å. Mn2+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with three equivalent LiO6 octahedra and corners with nine equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 59–63°. There are three shorter (2.08 Å) and one longer (2.10 Å) Mn–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Li1+ and three equivalent Nb4+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+ and two equivalent Nb4+ atoms. In the third O2- site, O2- is bonded to one Li1+, two equivalent Nb4+, and one Mn2+ atom to form a mixture of distorted edge and corner-sharing OLiMnNb2 trigonal pyramids. In the fourth O2- site, O2- is bonded to three equivalent Nb4+ and one Mn2+ atom to form a mixture of distorted edge and corner-sharing OMnNb3 trigonal pyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020