LiO2
lithium superoxide
Lithium superoxide is a metastable, semimetallic lithium oxide that acts as a key intermediate in lithium-oxygen battery chemistry.
About lithium superoxide
Lithium superoxide is a reactive, metastable member of the lithium oxide family. Its electronic structure is characterized as near-zero-gap, placing it in a semimetallic regime that distinguishes it from the insulating nature of many other binary lithium oxides.
This compound is primarily significant as a transient species in the electrochemical pathways of lithium-air batteries. Because it is not thermodynamically stable, it is highly sought after for research into reaction kinetics and the stabilization of discharge products in energy storage technologies.
Key Properties
Cross-validated computational properties for lithium superoxide, aggregated across 5 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of LiO2. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for LiO2, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| — | — | 0.00 | 0.0000 | -1.192 | — |
| Pnnm (No. 58) | orthorhombic | 0.00 | 0.0131 | -1.074 | — |
| Pnnm (No. 58) | orthorhombic | 0.00 | 0.0831 | -4.978 | 2.24 |
| Pmmm (No. 47) | orthorhombic | 0.00 | 0.1391 | -0.948 | — |
| C2/m (No. 12) | monoclinic | 0.00 | 0.3169 | -4.744 | 2.35 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.5683 | -0.519 | — |
| R-3m (No. 166) | trigonal | 0.07 | 0.5915 | -4.469 | 2.24 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.6860 | -4.375 | 2.60 |
| R-3m (No. 166) | trigonal | 0.00 | 0.8363 | -0.251 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.8885 | -0.199 | — |
| — | — | 0.00 | 0.9387 | -0.253 | — |
| — | — | 0.00 | 1.0753 | -0.117 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting LiO2.
Applications
Where lithium superoxide is used.
Frequently Asked Questions
Common questions about lithium superoxide, answered from cross-validated data.
What is LiO2?
Lithium superoxide is a metastable, semimetallic lithium oxide that acts as a key intermediate in lithium-oxygen battery chemistry.
What is LiO2 used for?
What is the band gap of LiO2?
Is LiO2 a metal, semiconductor, or insulator?
Is LiO2 thermodynamically stable?
What is the crystal structure of LiO2?
How many polymorphs of LiO2 are known?
How is LiO2 synthesized?
What elements does LiO2 contain?
Where does the data for LiO2 come from?
How It Compares
Within the lithium oxides class.
Unlike the highly stable Li2O or the robust, commercially established cathode materials like LiCoO2 and LiMn2O4, LiO2 exists as a fleeting and metastable phase. While its siblings in the lithium oxide class are typically utilized as structural components or stable electrodes, LiO2 is studied for its role as a reactive intermediate that dictates the efficiency and cycle life of next-generation power cells.
Related Compounds
Other Lithium Oxides in the database.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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