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11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on LiO2 by Materials Project

LiO2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Li is bonded to six equivalent O atoms to form LiO6 octahedra that share corners with eight equivalent LiO6 octahedra, corners with six equivalent OLi3O tetrahedra, and edges with two equivalent LiO6 octahedra. The corner-sharing octahedral tilt angles are 69°. There are two shorter (2.10 Å) and four longer (2.13 Å) Li–O bond lengths. O is bonded to three equivalent Li and one O atom to form distorted OLi3O tetrahedra that share corners with three equivalent LiO6 octahedra, corners with thirteen equivalent OLi3O tetrahedra, and an edgeedge with one OLi3O tetrahedra. The corner-sharing octahedra tilt angles range from 65–66°. The O–O bond length is 1.34 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiO2 by Materials Project

LiO2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Li is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Li–O bond distances ranging from 2.09–2.27 Å. There are two inequivalent O sites. In the first O site, O is bonded in a 6-coordinate geometry to four equivalent Li and two equivalent O atoms. Both O–O bond lengths are 1.75 Å. In the second O site, O is bonded in a 4-coordinate geometry to four equivalent Li and two equivalent O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiO2 by Materials Project

LiO2 is Fluorite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Li is bonded in a body-centered cubic geometry to eight equivalent O atoms. There are six shorter (2.00 Å) and two longer (2.01 Å) Li–O bond lengths. O is bonded to four equivalent Li atoms to form a mixture of corner and edge-sharing OLi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiO2 by Materials Project

LiO2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Li is bonded in a distorted body-centered cubic geometry to eight equivalent O atoms. There are six shorter (2.13 Å) and two longer (2.23 Å) Li–O bond lengths. O is bonded in a 4-coordinate geometry to four equivalent Li atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Template Assisted Lithium Superoxide Growth for Lithium-Oxygen Batteries

Developing batteries with energy densities comparable to internal combustion technology is essential for a worldwide transition to electrified transportation. Li-O2 batteries are seen as the ‘holy grail’ of battery technologies since they have the highest theoretical energy density of all battery technologies. Current lithium-oxygen (Li-O2) batteries suffer from large charge overpotentials related to electronic resistivity of the insulating lithium peroxide (Li2O2) discharge product. One potential solution is the formation and stabilization of a lithium superoxide (LiO2) discharge intermediate that exhibits good electronic conductivity. However, LiO2 is reported to be unstable at ambient temperature despite its favorable formation energy at -1.0 eV/atom. In this paper, based on our recent work on the development of cathode materials for aprotic lithium oxygen batteries including two intermetallic compounds, LiIr3 and LiIr, that are found to form good template interfaces with LiO2, a simple goodness of fit R factor to gauge how well a template surface structure can support LiO2 growth is developed. The R factor is a quantitative measurement to calculate the geometric difference in the unit cells of specific Miller Index 2D planes of the template surface and LiO2. Using this as a guide, the R factors for LiIr3, LiIr, and La2NiO4+, are found to be good. This guide is attested by simple extension to other noble metal intermetallics with electrochemical cycling data including LiRh3, LiRh, and Li2Pd. Finally, the template concept is extended to main group elements and the R factors for LiO2 (111) and Li2Ca suggest that Li2Ca is a possible candidate for the template assisted LiO2 growth strategy.

Intermetallics↗
DOE OSTI2020

Materials Data on LiTi(SO)2 by Materials Project

LiO2TiS2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one LiO2 sheet oriented in the (0, 0, 1) direction and one TiS2 sheet oriented in the (0, 0, 1) direction. In the LiO2 sheet, Li1+ is bonded to six equivalent O2- atoms to form edge-sharing LiO6 octahedra. There are four shorter (1.91 Å) and two longer (2.51 Å) Li–O bond lengths. O2- is bonded in a 4-coordinate geometry to three equivalent Li1+ and one O2- atom. The O–O bond length is 1.37 Å. In the TiS2 sheet, Ti3+ is bonded to six equivalent S atoms to form edge-sharing TiS6 octahedra. There are two shorter (2.42 Å) and four longer (2.46 Å) Ti–S bond lengths. S is bonded in a distorted T-shaped geometry to three equivalent Ti3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiTi(SO)2 by Materials Project

LiO2TiS2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one LiO2 sheet oriented in the (0, 0, 1) direction and one TiS2 sheet oriented in the (0, 0, 1) direction. In the LiO2 sheet, Li1+ is bonded to six equivalent O2- atoms to form edge-sharing LiO6 octahedra. There are four shorter (1.91 Å) and two longer (2.56 Å) Li–O bond lengths. O2- is bonded in a 4-coordinate geometry to three equivalent Li1+ and one O2- atom. The O–O bond length is 1.38 Å. In the TiS2 sheet, Ti3+ is bonded to six equivalent S atoms to form edge-sharing TiS6 octahedra. There are two shorter (2.42 Å) and four longer (2.46 Å) Ti–S bond lengths. S is bonded in a distorted T-shaped geometry to three equivalent Ti3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiTi(SeO)2 by Materials Project

LiO2TiSe2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one LiO2 sheet oriented in the (0, 0, 1) direction and one TiSe2 sheet oriented in the (0, 0, 1) direction. In the LiO2 sheet, Li is bonded in a distorted hexagonal planar geometry to six equivalent O atoms. There are two shorter (2.07 Å) and four longer (2.09 Å) Li–O bond lengths. O is bonded in a trigonal non-coplanar geometry to three equivalent Li atoms. In the TiSe2 sheet, Ti is bonded to six equivalent Se atoms to form edge-sharing TiSe6 octahedra. All Ti–Se bond lengths are 2.55 Å. Se is bonded in a distorted T-shaped geometry to three equivalent Ti atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1981

Chemical and morphological characteristics of lithium electrode surfaces

Lithium electrode surfaces were analyzed for chemical and morphological characteristics, using electron spectroscopy chemical analysis (ESCA) and scanning electron microscopy (SEM). Samples included lithium metal and lithium electrodes which were cycled in a 1.5 M lithium arsenic hexafluoride/two-methyl tetrahydrofuran electrolyte. Results show that the surface of the as-received lithium metal was already covered by a film composed of LiO2 and an Li2O/CO2 adduct with a thickness of approximately 100-200 A. No evidence of Ni3 was found. Upon exposure of the lithium electrode to a 1.5 M LiAsF6/2-Me-THF electrochemical environment, a second film was observed to form on the surface, consisting primarily of As, Si, and F, possibly in the form of lithium arsenic oxyfluorides or lithium fluorosilicates. It is suggested that the film formation may be attributed to salt degradation.

Yen, S. P. S.↗
NASA NTRS1992

Theoretical determination of the alkali-metal superoxide bond energies

The bond dissociation energies for the alkali-metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional level. Our computed D0 values are 61.4, 37.2, 40.6, and 38.4 kcal/mol for LiO2, NaO2, KO2, and RbO2, respectively. These values, which are expected to be lower bounds and accurate to 2 kcal/mol, agree well with some of the older flame data, but rule out several recent experimental measurements.

Partridge, Harry↗
NASA NTRS1992

Theoretical study of the 2A2-2B2 separation of the alkali superoxides

The computed 2A2-2B2 separations of the alkali superoxides are in good agreement with those deduced from electron-spin resonance spectra. The calculations definitively show that the ground state of CsO2 is 2A2. The larger than expected separation for CsO2, based on the trend from LiO2 to RbO2, is attributed primarily to the differential effects of core relaxation. The CsO2 dissociation energy is computed to be 42.7 kcal/mol, with an uncertainty conservatively estimated as +/- 4 kcal/mol.

Bauschlicher, Charles W., Jr.↗