NiO2
nickel dioxide · nickel peroxide
Nickel dioxide is a semiconducting oxide material utilized primarily in research related to oxygen-evolution catalysis and electrochemical energy systems.
About nickel dioxide
Nickel dioxide is a semiconducting oxide that serves as a focal point in the study of oxygen-evolution catalysts. Its electronic properties make it a subject of significant interest for researchers aiming to optimize charge transfer processes in electrochemical devices.
Despite being recognized as thermodynamically unstable relative to other phases, this compound remains a highly studied material due to its complex structural landscape. It is frequently examined for its potential to facilitate critical oxidation reactions in energy storage and conversion technologies.
Key Properties
Cross-validated computational properties for nickel dioxide, aggregated across 6 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 NiO2. 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 NiO2, 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. |
|---|---|---|---|---|---|
| — | — | 2.52 | 0.0000 | -0.895 | — |
| R-3m (No. 166) | trigonal | 0.75 | 0.0000 | -0.833 | — |
| — | — | 2.38 | 0.0003 | -0.895 | — |
| Fd-3m (No. 227) | cubic | 1.10 | 0.0111 | -0.822 | — |
| P-3m1 (No. 164) | trigonal | 0.70 | 0.0139 | -0.819 | — |
| P-3m1 (No. 164) | trigonal | 0.77 | 0.0140 | -0.819 | — |
| C2 (No. 5) | monoclinic | 0.82 | 0.0145 | -0.818 | — |
| C2/m (No. 12) | monoclinic | 0.82 | 0.0145 | -0.818 | — |
| Cm (No. 8) | monoclinic | 0.82 | 0.0145 | -0.818 | — |
| C2/m (No. 12) | monoclinic | 0.82 | 0.0145 | -0.818 | — |
| R-3m (No. 166) | trigonal | 0.78 | 0.0156 | -0.817 | — |
| R-3m (No. 166) | trigonal | 0.78 | 0.0156 | -0.817 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting NiO2.
Applications
Where nickel dioxide is used.
Frequently Asked Questions
Common questions about nickel dioxide, answered from cross-validated data.
What is NiO2?
Nickel dioxide is a semiconducting oxide material utilized primarily in research related to oxygen-evolution catalysis and electrochemical energy systems.
What is NiO2 used for?
What is the band gap of NiO2?
Is NiO2 a metal, semiconductor, or insulator?
Is NiO2 thermodynamically stable?
What is the crystal structure of NiO2?
How many polymorphs of NiO2 are known?
How is NiO2 synthesized?
What elements does NiO2 contain?
Where does the data for NiO2 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Within the diverse family of oxide catalysts, NiO2 occupies a distinct position compared to more robust structures like NiO or the layered LiNiO2. While many of its class members, such as LaNiO3 or LiCoO2, are prized for their structural stability, NiO2 is often investigated for its unique reactivity and metastable nature, which can offer kinetic advantages in specific catalytic environments.
Related Compounds
Other Oxide Oxygen-Evolution Catalysts 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)
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