Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Defect Chemistry and Na-Ion Diffusion in Na3Fe2(PO4)3 Cathode Material.

ABSTRACT: In this work, we employ computational modeling techniques to study the defect chemistry, Na ion diffusion paths, and dopant properties in sodium iron phosphate [Na3Fe2(PO4)3] cathode material. The lowest intrinsic defect energy process (0.45 eV/defect) is calculated to be the Na Frenkel, which ensures the formation of Na vacancies required for the vacancy-assisted Na ion diffusion. A small percentage of Na-Fe anti-site defects would be expected in Na3Fe2(PO4)3 at high temperatures. Long-range diffusion of Na is found to be low and its activation energy is calculated to be 0.45 eV. Isovalent dopants Sc, La, Gd, and Y on the Fe site are exoergic, meaning that they can be substituted experimentally and should be examined further. The formation of Na vacancies and Na interstitials in this material can be facilitated by doping with Zr on the Fe site and Si on the P site, respectively.

SUBMITTER: Kuganathan N

PROVIDER: S-EPMC6515689 | biostudies-other | 2019 Apr

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Publications

Defect Chemistry and Na-Ion Diffusion in Na3Fe2(PO4)3 Cathode Material.

Kuganathan Navaratnarajah N Chroneos Alexander A

Materials (Basel, Switzerland) 20190425 8

In this work, we employ computational modeling techniques to study the defect chemistry, Na ion diffusion paths, and dopant properties in sodium iron phosphate [Na3Fe2(PO4)3] cathode material. The lowest intrinsic defect energy process (0.45 eV/defect) is calculated to be the Na Frenkel, which ensures the formation of Na vacancies required for the vacancy-assisted Na ion diffusion. A small percentage of Na-Fe anti-site defects would be expected in Na<s ...[more]

PMID: 31027175

Similar Datasets

Defect Chemistry, Sodium Diffusion and Doping Behaviour in NaFeO2 Polymorphs as Cathode Materials for Na-Ion Batteries: A Computational Study.

Project description:Minor metal-free sodium iron dioxide, NaFeO2, is a promising cathode material in sodium-ion batteries. Computational simulations based on the classical potentials were used to study the defects, sodium diffusion paths and cation doping behaviour in the ?- and ?-NaFeO2 polymorphs. The present simulations show good reproduction of both ?- and ?-NaFeO2. The most thermodynamically favourable defect is Na Frenkel, whereas the second most favourable defect is the cation antisite, in which Na and Fe exchange their positions. The migration energies suggest that there is a very small difference in intrinsic Na mobility between the two polymorphs but their migration paths are completely different. A variety of aliovalent and isovalent dopants were examined. Subvalent doping by Co and Zn on the Fe site is calculated to be energetically favourable in ?- and ?-NaFeO2, respectively, suggesting the interstitial Na concentration can be increased by using this defect engineering strategy. Conversely, doping by Ge on Fe in ?-NaFeO2 and Si (or Ge) on Fe in ?-NaFeO2 is energetically favourable to introduce a high concentration of Na vacancies that act as vehicles for the vacancy-assisted Na diffusion in NaFeO2. Electronic structure calculations by using density functional theory (DFT) reveal that favourable dopants lead to a reduction in the band gap.

| S-EPMC6803870 | biostudies-literature

Defect Chemistry and Li-ion Diffusion in Li2RuO3.

Project description:Layered Li2RuO3 is an important candidate cathode material in rechargeable lithium ion batteries because of its novel anionic redox process and high reversible capacity. Atomistic scale simulations are used to calculate the intrinsic defect process, favourable dopants and migration energies of lithium ion diffusions together with migration paths in Li2RuO3. The Li Frenkel is calculated to be the most favourable intrinsic defect type. The cation anti-site defect, in which Li and Ru ions exchange their positions is 1.89?eV/defect suggesting that this defect would be observed at high temperatures. Long range vacancy assisted lithium diffusion paths were calculated and it is confirmed that the lowest overall activation energy (0.73?eV) migration path is along the ab plane. Trivalent dopants (Al3+, Co3+, Sc3+, In3+, Y3+, Gd3+ and La3+) were considered to create additional Li in Li2RuO3. Here we show that Al3+ or Co3+ are the ideal dopants and this is in agreement with the experimental studies reported on Co3+ doping in Li2RuO3.

| S-EPMC6345755 | biostudies-literature

Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries.

Project description:Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe(2+)/Fe(3+) and Fe(3+)/Fe(4+) redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0-4.55?V.

| S-EPMC3942702 | biostudies-literature

Defect-free potassium manganese hexacyanoferrate cathode material for high-performance potassium-ion batteries.

Project description:Potassium-ion batteries (KIBs) are promising electrochemical energy storage systems because of their low cost and high energy density. However, practical exploitation of KIBs is hampered by the lack of high-performance cathode materials. Here we report a potassium manganese hexacyanoferrate (K2Mn[Fe(CN)6]) material, with a negligible content of defects and water, for efficient high-voltage K-ion storage. When tested in combination with a K metal anode, the K2Mn[Fe(CN)6]-based electrode enables a cell specific energy of 609.7 Wh kg-1 and 80% capacity retention after 7800 cycles. Moreover, a K-ion full-cell consisting of graphite and K2Mn[Fe(CN)6] as anode and cathode active materials, respectively, demonstrates a specific energy of 331.5 Wh kg-1, remarkable rate capability, and negligible capacity decay for 300 cycles. The remarkable electrochemical energy storage performances of the K2Mn[Fe(CN)6] material are attributed to its stable frameworks that benefit from the defect-free structure.

| S-EPMC8041879 | biostudies-literature

Li2SnO3 as a Cathode Material for Lithium-ion Batteries: Defects, Lithium Ion Diffusion and Dopants.

Project description:Tin-based oxide Li2SnO3 has attracted considerable interest as a promising cathode material for potential use in rechargeable lithium batteries due to its high- capacity. Static atomistic scale simulations are employed to provide insights into the defect chemistry, doping behaviour and lithium diffusion paths in Li2SnO3. The most favourable intrinsic defect type is Li Frenkel (0.75?eV/defect). The formation of anti-site defect, in which Li and Sn ions exchange their positions is 0.78?eV/defect, very close to the Li Frenkel. The present calculations confirm the cation intermixing found experimentally in Li2SnO3. Long range lithium diffusion paths via vacancy mechanisms were examined and it is confirmed that the lowest activation energy migration path is along the c-axis plane with the overall activation energy of 0.61?eV. Subvalent doping by Al on the Sn site is energetically favourable and is proposed to be an efficient way to increase the Li content in Li2SnO3. The electronic structure calculations show that the introduction of Al will not introduce levels in the band gap.

| S-EPMC6105723 | biostudies-literature

Twin boundary defect engineering improves lithium-ion diffusion for fast-charging spinel cathode materials.

Project description:Defect engineering on electrode materials is considered an effective approach to improve the electrochemical performance of batteries since the presence of a variety of defects with different dimensions may promote ion diffusion and provide extra storage sites. However, manipulating defects and obtaining an in-depth understanding of their role in electrode materials remain challenging. Here, we deliberately introduce a considerable number of twin boundaries into spinel cathodes by adjusting the synthesis conditions. Through high-resolution scanning transmission electron microscopy and neutron diffraction, the detailed structures of the twin boundary defects are clarified, and the formation of twin boundary defects is attributed to agminated lithium atoms occupying the Mn sites around the twin boundary. In combination with electrochemical experiments and first-principles calculations, we demonstrate that the presence of twin boundaries in the spinel cathode enables fast lithium-ion diffusion, leading to excellent fast charging performance, namely, 75% and 58% capacity retention at 5 C and 10 C, respectively. These findings demonstrate a simple and effective approach for fabricating fast-charging cathodes through the use of defect engineering.

| S-EPMC8149699 | biostudies-literature

Perylenetetracarboxylic Diimide as Diffusion-Less Electrode Material for High-Rate Organic Na-Ion Batteries.

Project description:In this work 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) is investigated as electrode material for organic Na-ion batteries. Since PTCDI is a widely used industrial pigment, it may turn out to be a cost-effective, abundant, and environmentally benign cathode material for secondary Na-ion batteries. Among other carbonyl pigments, PTCDI is especially interesting due to its high Na-storage capacity in combination with remarkable high rate capabilities. The detailed analysis of cyclic voltammetry measurements reveals a diffusion-less mechanism, suggesting that Na-ion storage in the PTCDI film allows for exceptionally fast charging/discharging rates. This finding is further corroborated by galvanostatic sodiation measurements at high rates of 17 C (2.3 A g-1 ), showing that 57 % of the theoretically possible capacity of PTCDI, or 78 mAh g-1 , are attained in only 3.5 min charging time.

| S-EPMC7839514 | biostudies-literature

Hybrid Functional Study on Small Polaron Formation and Ion Diffusion in the Cathode Material Na2Mn3(SO4)4.

Project description:The crystal structure, electronic structure, and diffusion mechanism of Na ions in the cathode material Na2Mn3(SO4)4 are investigated based on the Heyd-Scuseria-Ernzerhof hybrid density functional method. The simultaneous motion model of polaron-sodium vacancy complexes was used to reveal the diffusion mechanism of Na ions in this material. Polaron formation at the Mn third-nearest neighbor to the Na vacancy was found. Two crossing and two parallel elementary diffusion processes of the polaron-Na vacancy complex were explored. The most preferable elementary diffusion process has an activation energy of 852 meV, which generates a zigzag-like pathway of Na-ion diffusion along the [001] direction in the whole material. Possessing a voltage of 4.4 V and an activation energy of 852 meV, Na2Mn3(SO4)4 is expected to be a good cathode material for rechargeable sodium ions.

| S-EPMC7081391 | biostudies-literature

A fluoroxalate cathode material for potassium-ion batteries with ultra-long cyclability.

Project description:Potassium-ion batteries are a compelling technology for large scale energy storage due to their low-cost and good rate performance. However, the development of potassium-ion batteries remains in its infancy, mainly hindered by the lack of suitable cathode materials. Here we show that a previously known frustrated magnet, KFeC2O4F, could serve as a stable cathode for potassium ion storage, delivering a discharge capacity of ~112 mAh g-1 at 0.2 A g-1 and 94% capacity retention after 2000 cycles. The unprecedented cycling stability is attributed to the rigid framework and the presence of three channels that allow for minimized volume fluctuation when Fe2+/Fe3+ redox reaction occurs. Further, pairing this KFeC2O4F cathode with a soft carbon anode yields a potassium-ion full cell with an energy density of ~235 Wh kg-1, impressive rate performance and negligible capacity decay within 200 cycles. This work sheds light on the development of low-cost and high-performance K-based energy storage devices.

| S-EPMC7060185 | biostudies-literature

Higher energy and safer sodium ion batteries via an electrochemically made disordered Na3V2(PO4)2F3 material.

Project description:The growing need to store an increasing amount of renewable energy in a sustainable way has rekindled interest for sodium-ion battery technology, owing to the natural abundance of sodium. Presently, sodium-ion batteries based on Na3V2(PO4)2F3/C are the subject of intense research focused on improving the energy density by harnessing the third sodium, which has so far been reported to be electrochemically inaccessible. Here, we are able to trigger the activity of the third sodium electrochemically via the formation of a disordered NaxV2(PO4)2F3 phase of tetragonal symmetry (I4/mmm space group). This phase can reversibly uptake 3 sodium ions per formula unit over the 1 to 4.8?V voltage range, with the last one being re-inserted at 1.6?V vs Na+/Na0. We track the sodium-driven structural/charge compensation mechanism associated to the new phase and find that it remains disordered on cycling while its average vanadium oxidation state varies from 3 to 4.5. Full sodium-ion cells based on this phase as positive electrode and carbon as negative electrode show a 10-20% increase in the overall energy density.

| S-EPMC6362244 | biostudies-literature