NaNiO2
sodium nickelate
NaNiO2 is a stable, semiconducting layered oxide used primarily as a cathode material in sodium-ion battery research.
About sodium nickelate
NaNiO2 belongs to the family of layered sodium transition-metal oxides, characterized by its stable structural arrangement on the convex hull. As a semiconducting material, it plays a vital role in the development of electrochemical energy storage systems where efficient ion transport and structural integrity are paramount.
Its significance lies in its potential as a high-performance cathode material for next-generation sodium-ion batteries. The material is the subject of extensive research due to its ability to facilitate stable cycling, making it a critical focus for researchers aiming to move beyond lithium-based technologies.
Key Properties
Cross-validated computational properties for sodium nickelate, 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 NaNiO2. 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 NaNiO2, 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. |
|---|---|---|---|---|---|
| — | — | 0.43 | 0.0000 | -1.310 | — |
| C2/m (No. 12) | monoclinic | 0.00 | 0.0000 | -5.588 | 4.85 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.0000 | -1.313 | — |
| P21/c (No. 14) | monoclinic | 0.26 | 0.0077 | -5.580 | 4.85 |
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.0105 | -1.302 | — |
| C2/m (No. 12) | monoclinic | 0.00 | 0.0105 | -1.302 | — |
| P21/m (No. 11) | monoclinic | 0.35 | 0.0128 | -5.575 | 4.60 |
| C2/c (No. 15) | monoclinic | 0.00 | 0.0128 | -1.300 | — |
| P21/c (No. 14) | monoclinic | 0.00 | 0.0133 | -1.299 | — |
| Cmcm (No. 63) | orthorhombic | 0.20 | 0.0143 | -5.573 | 4.82 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.0144 | -1.298 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.0162 | -1.296 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting NaNiO2.
Applications
Where sodium nickelate is used.
Frequently Asked Questions
Common questions about sodium nickelate, answered from cross-validated data.
What is NaNiO2?
NaNiO2 is a stable, semiconducting layered oxide used primarily as a cathode material in sodium-ion battery research.
What is NaNiO2 used for?
What is the band gap of NaNiO2?
Is NaNiO2 a metal, semiconductor, or insulator?
Is NaNiO2 thermodynamically stable?
What is the crystal structure of NaNiO2?
What is the density of NaNiO2?
How many polymorphs of NaNiO2 are known?
How is NaNiO2 synthesized?
What elements does NaNiO2 contain?
Where does the data for NaNiO2 come from?
Related Research
How It Compares
Within the layered sodium transition-metal oxides class.
Within the group of layered sodium transition-metal oxides, NaNiO2 stands out as a highly studied material compared to counterparts like NaFeO2 or NaMnO2. While many members of this class exhibit diverse structural variations, NaNiO2 is distinguished by its thermodynamic stability and its specific electronic properties that favor its application in battery architectures over more complex oxides like Na2Ti3O7.
Related Compounds
Other Layered Sodium Transition-Metal 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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