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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on LiMnO2 by Materials Project

LiMnO2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Li1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.91–2.08 Å. Mn3+ is bonded to six O2- atoms to form distorted edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.94–2.52 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form distorted OLi3Mn3 octahedra that share corners with six equivalent OLiMn3 tetrahedra, edges with six equivalent OLi3Mn3 octahedra, and edges with three equivalent OLiMn3 tetrahedra. In the second O2- site, O2- is bonded to one Li1+ and three equivalent Mn3+ atoms to form distorted OLiMn3 tetrahedra that share corners with six equivalent OLi3Mn3 octahedra, corners with six equivalent OLiMn3 tetrahedra, and edges with three equivalent OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 3–61°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiMnO2 by Materials Project

LiMnO2 is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with four equivalent LiO6 octahedra, edges with four equivalent LiO6 octahedra, and edges with eight equivalent MnO6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are four shorter (2.11 Å) and two longer (2.28 Å) Li–O bond lengths. Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent MnO6 octahedra, edges with four equivalent MnO6 octahedra, and edges with eight equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are two shorter (1.96 Å) and four longer (2.11 Å) Mn–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form a mixture of corner and edge-sharing OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the second O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form a mixture of corner and edge-sharing OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (1.96 Å) and two longer (2.11 Å) O–Mn bond lengths. In the third O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form a mixture of corner and edge-sharing OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are two shorter (2.11 Å) and one longer (2.28 Å) O–Li bond lengths. In the fourth O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form a mixture of corner and edge-sharing OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are two shorter (2.11 Å) and one longer (2.28 Å) O–Li bond lengths. In the fifth O2- site, O2- is bonded to three equivalent Li1+ and three equivalent Mn3+ atoms to form a mixture of corner and edge-sharing OLi3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°.

36 MATERIALS SCIENCE↗
DOE OSTI2025

LiMnO2 polymorphs

Energies of LiMnO2 polymorphs computed within various DFT approximations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiMnO2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2025

Interplay between electron localization, magnetic order, and Jahn-Teller distortion dictates LiMnO2 phase stability

The development of manganese (Mn)-rich cathodes for Li-ion batteries promises to alleviate potential supply chain bottlenecks in battery manufacturing. Fundamental challenges in Mn-rich cathodes arise from phenomena such as structural changes due to cooperative Jahn-Teller (JT) distortions of in octahedral environments, Mn migration, and phase transformations to spinel-like order, all of which affect the electrochemical performance. These physically complex phenomena motivate an re-examination of the Li-Mn-O rock-salt space, with a focus on the thermodynamics of the prototypical, polymorphs. It is found that the generalized gradient approximation (GGA-PBEsol) and meta-GGA ( ) density functionals with empirically fitted on-site Hubbard corrections yield spurious stable phases for , such as predicting a phase with -like order ( ) to be the ground state instead of the orthorhombic (Pmmn) phase, which is the experimentally known ground state. Accounting for antiferromagnetic order in each structure is shown to have a substantial effect on the total energies and resulting phase stability. By using hybrid-GGA (HSE06) and GGA with self-consistent Hubbard parameters (on-site and inter-site ) calculated from linear response theory, the experimentally observed phase stability trends are recovered. The calculated on-site between Mn- states in the experimentally observed orthorhombic, layered, and spinel phases are significantly smaller than in and disordered layered structures, by within GGA. The smaller values of are shown to be correlated with a collinear ordering of JT distortions, in which all orbitals are oriented in the same direction. This cooperative JT effect can lead to greater electron delocalization from Mn along the states due to increased Mn-O covalency, which contributes to the greater electronic stability compared to the phases with noncollinear JT arrangements. The structures with collinear ordering of JT distortions also generate greater vibrational entropy, which helps stabilize these phases at high temperature. These phases are shown to be strongly insulating with large calculated band gaps , which are computed using HSE06 and .

Kam, Ronald L↗