A3V2(PO4)3 (A = Na or Li) probed by in situ X-ray absorption spectroscopy

Pivko, Maja; Arčon, Iztok; Bele, Marjan; Dominko, Robert; Gaberšček, Miran

doi:10.1016/j.jpowsour.2012.05.037

Cited by 61 publications

(42 citation statements)

References 20 publications

(29 reference statements)

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“…The flat plateaus at 3.35 V and 3.41 V during discharge and charge, respectively, are assigned to the reversible insertion of 2 Na + per formula unit along to the reversible oxidation of the V 4+ /V 3+ redox couple. This profile is typical of a two‐phase mechanism as widely reported . As can be seen, the extent of this plateau depended on the silicon content, a lighter atom than phosphorous.…”

Section: Resultssupporting

confidence: 76%

On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

et al. 2017

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A new Na3+xV2(PO4)3−x(SiO4)x (0≤x≤0.5) series is examined as the positive electrodes for sodium‐ion cells. The substitution of P by Si is evidenced by an increase in the lattice parameters and a significant modification of the particle morphology. These structural and morphological changes significantly affect the electrochemical performance. Thus, samples with low Si contents reveal better rate capabilities and cyclabilities than the Si‐free sample. A full ion cell assembled with a selected sample provides an energy density of 342 W h kg−1 after 140 cycles, demonstrating that Si doping on Na3V2(PO4)3 could be an interesting strategy for high‐performance Na‐ion cells.

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Section: Resultssupporting

confidence: 76%

On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

et al. 2017

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“…1595cm À1 is characteristico fi nplane displacement of carbon atoms in the graphene sheetso f crystalline domains. [33][34][35] Thep articipation of the V V /V IV redox couple in the electrochemical reaction has been predicted. [30,31] It is commonly reported that the I G /I D1 ratio is am easureo ft he level of graphitization of the carbon material.…”

Section: Resultsmentioning

confidence: 97%

Induced Rate Performance Enhancement in Off‐Stoichiometric Na_3+3xV_2−x(PO₄)₃ with Potential Applicability as the Cathode for Sodium‐Ion Batteries

Aragón

Lavela

Ortiz

et al. 2017

Chemistry A European J

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Off-stoichiometric Na V (PO ) samples have been prepared by a sol-gel route. X-ray diffraction and XPS revealed the flexibility of the NASICON framework to accommodate these deviations of the stoichiometry; at least for low x values. X-ray photoelectron spectra evidenced the presence of Na P O impurities. The synergic combination of the structural deviations and the presence of Na P O impurities induce a significant improvement of the electrochemical performance and cycling stability at high rates, as compared to the stoichiometric Na V (PO ) sample. The fast kinetic response provided by the induced off-stoichiometry involves a decrease of the cell resistance.

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“…33 Other authors have also reported the presence of this unique plateau as responsible for the extraction of sodium atoms located in M2 sites with the parallel oxidation of V 3+ to V 4+ . [19][20][21] Figure 4 shows the cyclic voltammograms recorded for our samples at a scan rate of 0.5 mV s −1 . The non-substituted sample is characterized by anodic and cathodic signals respectively occurring at 3.54 and 3.25 V. No additional feature was observed, similarly to the results reported by others authors.…”

Section: Resultsmentioning

confidence: 99%

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

Aragón

Lavela

Ortiz

2015

J. Electrochem. Soc.

145

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Na 3 V 2-x Fe x (PO 4 ) 3 /C (0 ≤ x ≤ 0.5) samples were prepared by a simple sol-gel method. X-ray diffraction patterns revealed high purity and crystalline phosphate indexed in the R-3c space group. On increasing the iron content, the cell volume increases due to the slightly higher radius of Fe 3+ . Cyclic voltammetry showed two signals at ca. 3.5 and 4.0 V, which evidence a linear dependence of potential on the level of substitution. The appearance of the short plateau at ca. 4.0 V is closely related to the higher iron substitution levels. The evaluation of XPS and 57 Fe Mössbauer spectra of charged and discharged electrodes allow ascribing the 4.0 V plateau to V 4+ /V 5+ redox reaction and the extraction/insertion of extra sodium ions from octahedral M1 sites. Galvanostatic cycling showed capacity values as high as 115 mA h g −1 for samples with x = 0.1, 0. Now that lithium-ion battery (LIB) technology is reaching maturity, a number of reports are advising for the future scarcity of the lithium resources. A full implementation of LIB in the electric vehicle market would involve important constraints on Li production and an undesirable increase of the cost of Li is expected at the long term.1-4 For these reasons, market is alternatively looking forward beyond LIB and new chemistries are being explored. [5][6][7][8] Sodium is an abundant and non-toxic alkali element which can be implemented in insertion based batteries. The electrochemical principles are identical to those of lithium batteries. In fact, a number of recent reports have demonstrated the reliability of sodium batteries to provide reversible energy storage devices. [9][10][11][12] Nevertheless, the larger ionic radius and atomic weight leads to a less performing behavior. Thus, low theoretical capacity and cell voltage, slow diffusion, high unit cell volume change and hence structural impact are detected in electrodes subjected to sodium insertion. Recently, Ceder et al. have reported that the lower voltage for sodium insertion is predominantly a cathodic effect because of the diminished energy gain when inserting this alkaline ion into the host structure. Also, they pointed out to open structures, as layered and NASICON ones, as the most favored frameworks to provide phase stability on cycling. 13 The optimistic arguments promoting these cathode materials are mainly based on an easy transfer reaction of less solvated large ions and high sodium conductivity. 14,15 In this regard, transition metal phosphates with general stoichiometry A x B 2 (PO 4 ) 3 (A: Li + , Na + , etc; B: Fe 3+ , V 3+ , Ti 4+ .) offer a wide compositional variety exhibiting a NASICON-type structure. [16][17][18] Among them, Na 3 V 2 (PO 4 ) 3 has demonstrated interesting properties as a cathode material because of the high operating voltage and good cyclability. [19][20][21][22] Multivalent vanadium atom lends a significant electronic conductivity which promotes the chemical diffusion of sodium ions to this compound. Nevertheless, the electronic conductivity is not high enoug...

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A3V2(PO4)3 (A = Na or Li) probed by in situ X-ray absorption spectroscopy

Cited by 61 publications

References 20 publications

On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

Induced Rate Performance Enhancement in Off‐Stoichiometric Na_3+3xV_2−x(PO₄)₃ with Potential Applicability as the Cathode for Sodium‐Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries

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A3V2(PO4)3 (A = Na or Li) probed by in situ X-ray absorption spectroscopy

Cited by 61 publications

References 20 publications

On the Effect of Silicon Substitution in Na3V2(PO4)3 on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

On the Effect of Silicon Substitution in Na3V2(PO4)3 on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

Induced Rate Performance Enhancement in Off‐Stoichiometric Na3+3xV2−x(PO4)3 with Potential Applicability as the Cathode for Sodium‐Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na3V2(PO4)3as Cathode for Na-Ion Batteries

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On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

On the Effect of Silicon Substitution in Na₃V₂(PO₄)₃ on the Electrochemical Behavior as Cathode for Sodium‐Ion Batteries

Induced Rate Performance Enhancement in Off‐Stoichiometric Na_3+3xV_2−x(PO₄)₃ with Potential Applicability as the Cathode for Sodium‐Ion Batteries

Effect of Iron Substitution in the Electrochemical Performance of Na₃V₂(PO₄)₃as Cathode for Na-Ion Batteries