Jump diffusion coefficient of different cations intercalated into amorphous WO3

García-Belmonte, Germà; Garcı́a-Cañadas, Jorge; Bisquert, Juan; Person, Carles

doi:10.1016/j.ssi.2006.02.015

Cited by 4 publications

(5 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the fact that D exhibits higher values for the smallest ion (H + ), and decreases as the ion size enlarges (H + → Li + → Na + ), as well as the fact that D is higher for amorphous than for crystalline samples, is not surprising. 14,22 Comparing the present results with results of former workers, [12][13][14][15][16][17][18][34][35][36][37][38][39][40][41][42][43][44] the observed trends are similar, but most D values are slightly higher than those obtained earlier. It is believed that since D was measured by a pulse charging technique characterized by short relaxation periods and short discharge pulses interspersed during the intercalation process, the active material can be used in where M = H, Li, Na, and 0.01 ≤ x ≤ 0.08.…”

Section: Resultssupporting

confidence: 83%

“…It is believed that the rate-controlling step of colouration is the diffusion of cation M + into WO 3−δ thin films. 5,7,9,[11][12][13][14] A few measurements of diffusivity have been made for H + , Li + and Na + in WO 3 thin films by electrochemical methods. 5,11,[15][16][17][18][19] The values obtained for the diffusivity of each ionic species are quite different and extend along a large data range; for example, for similar procedure conditions, Li + diffusivities are in the range of 10 −11 − 10 −16 cm 2 s −1 , and H + diffusivities are in the range of 10 −9 − 10 −12 cm 2 s −1 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Cation Diffusivity in Nonstoichiometric Tungsten Trioxide Films

Sequeira¹,

Rodrigues²,

Santos³

2012

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

Nonstoichiometric WO3−δ thin films, with oxygen deficiencies, δ, varying between 0.05 and 0.01, were prepared by RF sputtering. These values were determined by a method of chemical analysis consisting in the oxidation of the tungsten ion with less charge than +6 to W6+ by means of a KMnO4 solution. The electrochromic process in WO3−δ / MxWO3−δ, where M = H, Li, Na and 0.01 ≤ x ≤ 0.08, occurs reversibly. It is believed that the rate-controlling step of coloration is the diffusion of cation M+ into WO3−δ thin films. The cation diffusivity in the thin films was measured as a function of their δ and x values by means of a current-pulse-relaxation technique. The diffusivities, D, were about 5 × 10−10 cm2 s−1, 2 × 10−10 cm2 s−1, and 1 × 10−10 cm2 s−1 for H+, Li+, and Na+, respectively, in the stoichiometric films at 300 K. D values increased with an increase of oxygen deficiency and slightly increased or decreased with an increase of cation content. The pulse technique used may probably be responsible for the higher diffusivities obtained, as compared with results for similar systems provided by previous workers.

show abstract

Section: Resultssupporting

confidence: 83%

mentioning

confidence: 99%

Cation Diffusivity in Nonstoichiometric Tungsten Trioxide Films

Sequeira¹,

Rodrigues²,

Santos³

2012

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The results are in line with the hypothesis that the diffusion coefficients are dependent of the matrix WO 3 -cases A and B-or WO 3 +NASICON -case C-and they are not correlated with the electrolyte. Moreover both D values in the configurations A and B are in the range quoted in literature [24,[51][52][53]. It is also noticeable that the determined D values for Na + cation (10 −11 to 10 −12 cm².s −1 ) are close to those reported for Li + (10 −9 to 10 −12 cm 2 .s −1 ) [24,54,55,27] or also K + (10 −11 cm 2 .s −1 ) [19], in the same WO 3 matrix.…”

Section: Discussionmentioning

confidence: 67%

Towards enhanced durability of electrochromic WO3 interfaced with liquid or ceramic sodium-based electrolytes

Zimmer

Tresse

Stein

et al. 2020

Electrochimica Acta

View full text Add to dashboard Cite

The reversible intercalation of sodium ion into tungsten oxide WO 3 appears as an interesting alternative to hydrogen or lithium ion reduction in order to get the characteristic transition from clear transparent to bluish coloration in electrochromic devices, but it has been comparatively less considered. In order to address further viable all-ceramic devices based on sodium ion intercalation and overcome the issue of WO 3 degradation in aqueous media, three configurations of WO 3 thin film-based electrochromic half-cells were tested, namely in (i) aqueous acidified Na 2 SO 4 electrolyte, (ii) room temperature ionic liquid BEPipTFSI electrolyte and (iii) aqueous acidified Na 2 SO 4 electrolyte associated with an amorphous NASICON-cap onto WO 3 film. We compared their electro-optical characteristics during 100 voltammetry cycles, including the Na + diffusion coefficient calculated through electrochemical method. It is found that sputter-deposited amorphous WO 3 thin films on transparent conductive substrates is promising for electrochromic all-ceramic devices based on Na ion insertion. Electrochemical characterization in aqueous medium is not relevant to extract relevant data when WO 3 is in direct contact with the electrolyte as the electrochromic film is progressively dissolved. In contrast, WO 3 capped with oxide amorphous Na-ion conductor readily operates over 100 cycles, the capping layer preventing degradation by the aqueous medium. Alternatively, ionic liquid does not degrade the WO 3 film and can be employed to efficiently characterize the electro-optical performances.

show abstract

“…Note that because the value of E off -E on is normally small (<0.3 V), the obtained intrinsic pesudocapacitance of the redox reaction is normally much higher Downloaded by [United Arab Emirates University ] at 22:21 26 June 2016 than that of the double-layer. However, its contribution to total capacitance may not necessarily be that high because the operation voltage window of ES is much wider than E off -E on .…”

Section: Fundamental Electrochemistry Of Pseudocapacitancementioning

confidence: 99%

“…Intercalation exhibits a clear state separation during absorption seen in Figure 3.5 for a MoO 2 host material [2]. The chemical diffusion coefficient (D) relates Li flux to the concentration gradient, while the behavior for a dilute Li species is represented as the jump diffusion coefficient (D j ) [25,26]. The chemical diffusion coefficient (D) relates Li flux to the concentration gradient, while the behavior for a dilute Li species is represented as the jump diffusion coefficient (D j ) [25,26].…”

Section: Pseudocapacitance Induced By Lithium Intercalationmentioning

confidence: 99%