Li2FeP2O7
Li2FeP2O7 is a pyrophosphate-based cathode material designed for use in high-performance lithium-ion batteries.

About Li2FeP2O7
Li2FeP2O7 is a pyrophosphate-based inorganic compound that functions as a cathode material within the broader family of phosphate-based battery electrodes. Characterized as a wide-band-gap insulator, it possesses a robust framework that facilitates lithium-ion transport while maintaining structural integrity during electrochemical cycling. Its thermodynamic stability near the hull suggests it is a viable candidate for practical synthesis and integration into energy storage systems. Researchers study this material to overcome the limitations of traditional cathode chemistries by leveraging the inductive effect of the pyrophosphate groups. Its ability to host lithium ions makes it a subject of significant interest for next-generation secondary battery technologies.
Key Properties
Cross-validated computational properties for Li2FeP2O7, aggregated across 3 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.
Reported Structures
Lowest-energy structures reported for Li2FeP2O7, 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. |
|---|---|---|---|---|---|
| P21 (No. 4) | monoclinic | 4.14 | 0.0044 | -7.383 | 2.81 |
| C2/c (No. 15) | monoclinic | 4.16 | 0.0055 | -7.382 | 2.55 |
| P21/c (No. 14) | monoclinic | 3.99 | 0.0125 | -7.375 | 3.00 |
| P-1 (No. 2) | triclinic | 4.25 | 0.0190 | -7.369 | 2.95 |
| P21/c (No. 14) | monoclinic | 3.87 | 0.0194 | -7.368 | 2.90 |
| P21/c (No. 14) | monoclinic | 4.22 | 0.0236 | -7.364 | 2.94 |
| P1 (No. 1) | triclinic | 2.92 | 0.0300 | -7.358 | 2.90 |
| P-1 (No. 2) | triclinic | 4.35 | 0.0318 | -7.356 | 2.91 |
| P-1 (No. 2) | triclinic | 4.35 | 0.0332 | -7.355 | 2.75 |
| C2/c (No. 15) | monoclinic | 4.46 | 0.0336 | -7.354 | 2.77 |
| C2/c (No. 15) | monoclinic | 3.67 | 0.0336 | -7.354 | 2.76 |
| P21/c (No. 14) | monoclinic | 1.76 | 0.0345 | -7.353 | 2.93 |
Applications
Where Li2FeP2O7 is used.
Frequently Asked Questions
Common questions about Li2FeP2O7, answered from cross-validated data.
What is Li2FeP2O7?
Li2FeP2O7 is a pyrophosphate-based cathode material designed for use in high-performance lithium-ion batteries.
What is Li2FeP2O7 used for?
What is the band gap of Li2FeP2O7?
Is Li2FeP2O7 a metal, semiconductor, or insulator?
Is Li2FeP2O7 thermodynamically stable?
What is the crystal structure of Li2FeP2O7?
What is the density of Li2FeP2O7?
How many polymorphs of Li2FeP2O7 are known?
What elements does Li2FeP2O7 contain?
Where does the data for Li2FeP2O7 come from?
How It Compares
Within the olivine phosphate cathodes class.
Within the class of phosphate-based cathode materials, Li2FeP2O7 offers a distinct structural arrangement compared to the well-known olivine-structured LiFePO4. While LiFePO4 remains the industry standard for its high stability and safety, the pyrophosphate framework of Li2FeP2O7 provides a different coordination environment for iron, which can influence the operating voltage and ion diffusion pathways differently than its olivine counterparts like LiMnPO4 or LiCoPO4.
Related Compounds
Other Olivine Phosphate Cathodes in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
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