Détermination du coefficient de diffusion du proton dans MnO2-γ par la méthode de résonance magnétique nucléaire

Kahil, H.; Dalard, F.; Guitton, J.; Cohen‐Addad, J. P.

doi:10.1016/0376-4583(82)90023-1

Cited by 28 publications

(13 citation statements)

References 8 publications

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“…It should be stressed from Table 1 that τ d was shortened in value with increasing heat-treatment temperature. Since the chemical diffusivity measured [29][30][31] actually decreases with decreasing hopping sites, it is conceivable to infer that the decrease in the amount of hydrates prolongs τ d . Nevertheless, as given in Table 1 τ d was measured to decrease in value with decreasing amount of hydrates.…”

Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 98%

“…By taking the value of chemical diffusivity of hydrogen ranging between 10 −10 and 10 −11 cm 2 s −1 which is reported by many researchers [29][30][31], the value of τ d for the hydrated electrode specimen is then estimated to range in 100-1000 s under the assumption that the diffusion depth is equal to the whole thickness of the film electrode specimen 1000 nm. However, the value of τ d was estimated to be 0.06-0.23 s (4.35-16.67 Hz) from the measured Warburg impedance.…”

Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 99%

“…(2) by taking the values of τ d from Table 1, assuming that the chemical diffusivity of hydrogen [29][30][31] is constant regardless of the amount of hydrates. The resulting values of L were approximately estimated to be 15-48 nm, 14-44 nm, 11-36 nm and 7-24 nm for the electrode specimens heat treated at 25, 50, 100 and 150 • C, respectively.…”

Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 99%

See 2 more Smart Citations

A study on mechanism of charging/discharging at amorphous manganese oxide electrode in 0.1M Na2SO4 solution

Chun

Pyun

Lee

2006

Electrochimica Acta

113

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Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 98%

Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 99%

Section: Factor Of Heat-treatment At 25-150 • C Controlling the Amounmentioning

confidence: 99%

See 1 more Smart Citation

A study on mechanism of charging/discharging at amorphous manganese oxide electrode in 0.1M Na2SO4 solution

Chun

Pyun

Lee

2006

Electrochimica Acta

113

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“…Since the solid phase of the separator is a nonconducting material, the OH-material balance, the overall material balance, and the overpotential are simply s ~t 2 + V-(C2 vc3) = 9 v 9 (DaVe2) [17] V. v c = 9 (Vc0). VV~ [18] C0V0 and ix 1 V~ =~ +~ [n@~ + t~ soc~]-ZlV~ nc00] v~ + ~F [s~V~ + s~Vpuj' [19] Governing equations in the anode.--In this model, the zinc anode is considered as a reversible, nonpolarizable electrode with a uniform current distribution.…”

Section: K = Ek~/t 2 [13]mentioning

confidence: 99%

Modeling of Cylindrical Alkaline Cells: III . Mixed‐Reaction Model for the Anode

Chen¹,

Cheh²

1993

J. Electrochem. Soc.

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q ABSTRACTA mixed-reaction model has been developed to simulate the discharge behavior of cylindrical alkaline zinc-manganese dioxide primary cells. The analysis of the system considers a whole prismatic cell consisting of a zinc amalgam anode, an inert porous separator, and a manganese dioxide cathode. The domain of investigation extends from the anode to the cathode current collector. The model is based on a macrohomogeneous theory of porous electrodes and includes considerations for the ohmic potential drop, diffusion and convection in the electrolyte, change in porosity and electrolyte composition due to chemical and electrochemical reactions, charge-transfer effects, and ionic transport in a concentrated electrolyte. The anode is considered to be a reversible, nonpolarizable electrode with two anodic reactions occurring simultaneously. A parameter which is based on the ratio of the extent of the two reactions is used to characterize the anode-mixed reactions. A solid-state proton diffusion as well as a direct charge transfer are used to describe the cathodic reaction. The performance between cells of different sizes is compared at the same galvanostatic discharge rates per unit cathode mass. Sources of polarization are identified, and the influence of cell behavior by the different operating variables are examined. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-06-26 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-06-26 to IP ABSTRACTA dissolution-precipitation model has been developed to simulate the discharge behavior of cylindrical alkaline zinc-manganese dioxide primary cells. The model is based on the macrohomogeneous theory of porous electrodes with the domain of investigation extending from the anode/anode current collector interface to the cathode/cathode current collector interface. The performance between cells of different sizes is compared at the same galvanostatic discharge rate per unit cathode mass. The reaction distribution, electrolyte concentration, overpotential, and porosity as a function of time and location in the cylindrical alkaline cell are presented.

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“…These studies have used a variety of characterization techniques from conventional electrochemical methods such as chronoamperometry [24], chronopotentiometry [23][24][25] and impedance spectroscopy [26], to various chemical techniques including leaching studies [27], isotope exchange [28], and nuclear magnetic resonance spectroscopy [29]. In all of these, the objective was to extract a diffusion coefficient for mass transport (D), or the term AÖD, where A is the electrochemically active surface area.…”

Section: Introductionmentioning

confidence: 99%

Proton diffusion in γ-manganese dioxide

Browning

Donne

2005

J Appl Electrochem

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Deconvolution of the electrolytic manganese dioxide (EMD) discharge curve has indicated the presence of a number of energetically different reduction processes. This has been used to determine the contribution of each reduction process to the total discharge. Using step potential electrochemical spectroscopy (SPECS), the i-t data were modelled as the sum of the discharge of the individual reduction processes. From this, AÖ D for each reduction process as a function of degree of discharge was determined. The maximum AÖ D values for each process ranged from 2.3 · 10 )2 to 4.0 · 10 )4 cm 3 s )1/2 g )1 values are consistent with previously reported values for AÖ D, although in this case we have determined values for the entire compositional range.

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Détermination du coefficient de diffusion du proton dans MnO2-γ par la méthode de résonance magnétique nucléaire

Cited by 28 publications

References 8 publications

A study on mechanism of charging/discharging at amorphous manganese oxide electrode in 0.1M Na2SO4 solution

A study on mechanism of charging/discharging at amorphous manganese oxide electrode in 0.1M Na2SO4 solution

Modeling of Cylindrical Alkaline Cells: III . Mixed‐Reaction Model for the Anode

Proton diffusion in γ-manganese dioxide

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