Sol-gel synthesis and XPS characterization of vanadium oxide bronzes

Bondarenka, V.

doi:10.3952/lithjphys.46201

Cited by 5 publications

(2 citation statements)

References 20 publications

(19 reference statements)

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“…In the last case the additional increase of the reduction ratio RR = C 4 /(C 4 + C 5 ) (C i is the atomic concentration of the i-valence ion) may be roughly estimated from the nominal chemical formulae, assuming that RR is the same for the basic V 2 O 5 layers and additional V 4+ ions from (VO) 2+ species; (2) by varying the concentration of V 4+ ions by some external treatment (thermal [44], UV irradiation [45], ion or electron bombardment [39,46]) and comparing photoelectron spectra before and after the treatment. The advantage of this technique is that the same sample is used to study the comparison spectra; therefore the structure-related effects may be neglected.…”

Section: The Aim Of Workmentioning

confidence: 99%

Valence of vanadium in hydrated compounds

Bondarenka¹

2007

Lithuanian J. Phys.

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Problems of the definition of vanadium chemical states in the mixed valency compounds are examined. The statistical analysis of the literature data on the values of binding energy and full width at half maximum (FWHM) of V 2p 3/2 peaks in different vanadium oxides is carried out.X-ray photoelectron spectroscopy was used to determine the chemical shift and FWHM of V 2p peaks of V 4+ and V 5+cations in the vanadium pentoxide matrix of hydrated vanadium compounds HV12O31·nH2O and (VO)V12O31·nH2O, prepared by using sol-gel technology. It was found that the binding energy of V 4+ ions shifts to the lower energy side of about 1.3 eV as compared to the main V 5+ ions in the matrix. The V 2p 3/2 line width for tetra-valent vanadium ions in xerogels is actually the same as for penta-valent ions.

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Section: The Aim Of Workmentioning

confidence: 99%

Valence of vanadium in hydrated compounds

Bondarenka¹

2007

Lithuanian J. Phys.

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“…Research results of X-ray photoelectron spectra of xerogels are described in [46][47][48][49][50][51][52][53][54]. It is known that this method allows determining the valence states of ions.…”

Section: X-ray Photoelectron Spectramentioning

confidence: 99%

Electrical properties of hydrated vanadium compounds

Bondarenka¹

2006

Lithuanian J. Phys.

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Vanadium pentoxide gels have a layered structure, where V-O ribbons are separated by water that permit to intercalate a wide range of various ionic and molecular species into these gels. They have both ionic and electronic conduction. The ionic part is defined by proton diffusion and the electronic one by the electron hopping between vanadium ions of different valence states. In this review the results of a complex study concerning the physical properties of a wide range of vanadium based hydrated compounds such as H2V12−xMexO 31±δ •nH2O (Me = Mo, Ti, Cr), Me2V12O 31±δ •nH2O (Me = Li, Na, K, Rb, Cs), and MeV12O 31±δ •nH2O (Me = Mg, Ca, Ba) are presented. The basic attention is given to the description of structure, synthesis, electrical properties, and valence conditions of metal ions in the xerogels.

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Ultrahigh‐Rate and Ultralong‐Duration Sodium Storage Enabled by Sodiation‐Driven Reconfiguration

Dong¹,

Xu²,

et al. 2023

Advanced Energy Materials

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paring to the scarce and nonuniform distributed lithium. [1] However, in practical applications, SIBs suffer from low capacity and poor rate performance owning to the large ionic radius of Na-ion. [2,3] Typically, to improve the electrochemical performance of SIBs during charge/discharge processes, different materials have been developed as anode electrodes for SIBs, including various carbonaceous materials, transition metal compounds and so on. [4,5] Among these, carbonaceous materials have limited capacities due to their poor storage capability for Na-ion, while transition metal compounds (TMDs) can make up these shortages and exhibit ideal theoretical specific capacities. [6,7] Vanadium sulfides (VS x ), with various crystal structures, such as VS 2 , V 2 S 3 , V 3 S 4 , V 5 S 8 and VS 4 have attracted increasing attention because they could offer proper interlayer spacing to accommodate Na + ions and have both intercalation/deintercalation and conversion energy storage processes. [8][9][10][11][12][13][14][15] For example, VS 2 with a large interlayer spacing of 0.575 nm delivered a higher theoretical specific capacity of about 800 mAh g −1 (comparing to 372 mAh g −1 of graphite anode in commercialized LIBs), suggesting that vanadiumbased sulfides could be a good candidate for SIBs. [11] Nevertheless, such vanadium-based sulfides frequently suffer significant mechanical pulverization during long-term cycling as a result of volume expansion caused by sodization/desodization, which results in severe irreversible capacity degradation and unsatisfactory cycling performance. [16,17] Up to now, the best (and one of the very few) cycling performance of all vanadium sulfides is V 5 S 8 /C electrode with 4000 cycles but only with a low specific capacity of 340 mAh g −1 (at 2 A g −1 ). [14] The best capacity performance so far of all vanadium sulfides is VS 4 -CN-Hs with 863 mA h g −1 at 0.1 A g −1 but only for 30 cycles. [15] Therefore, developing high-performance vanadium sulfide anode with both high capacity (energy density) and good cycling performance presents a key challenge for commercializing this vanadium sulfide-anode SIBs.3D micro/nanostructuring of vanadium sulfide anode might provide a clue to address the above challenge. Such 3D micro/nanostructures have been approved for overcoming Despite their variable valence and favorable sodiation/desodiation potential, vanadium sulfides (VS x ) used as anode materials of sodium-ion batteries (SIBs) have been held back by their capacity decline and low cycling capability, associated with the structure distortion volume expansion and pulverization. This study reports an accessible process to tackle these challenges via fabricating a 3D-VS x anode for SIBs with ultrahigh-rate and ultralong-duration stable sodium storage. The sodiation-driven reactivation of micro-nano 3D-VS x activates the reconfiguration effect, effectively maintaining structural integrity. Interestingly, the mechanical degradation of 3D-VS x over the sodiation process can be controlled by fine-tunin...

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Sol-gel synthesis and XPS characterization of vanadium oxide bronzes

Cited by 5 publications

References 20 publications

Valence of vanadium in hydrated compounds

Valence of vanadium in hydrated compounds

Electrical properties of hydrated vanadium compounds

Ultrahigh‐Rate and Ultralong‐Duration Sodium Storage Enabled by Sodiation‐Driven Reconfiguration

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