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Journal of Applied Electrochemistry

, Volume 2, Issue 2, pp 83–90 | Cite as

A mathematical model for platinum/ PTFE/porous nickel fuel cell oxygen diffusion electrodes

  • P. D. Power
  • M. J. R. Adams
Papers

Abstract

This paper describes the cylindrical agglomerate model for oxygen/alkali gas diffusion electrodes fabricated from platinum, PTFE and porous nickel. Corrections for the increase in hydroxyl ion concentration with increasing current density have been made to the original model of Brown and Horve. Changes in performance by variation of the bulk structural parameters, e.g. agglomerate radius, porosity and tortuosity, have been studied. Theoretical modes of electrode decay have been explored.

Keywords

Oxygen Porosity Nickel Mathematical Model Hydroxyl 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

α

Transfer coefficient

C

Concentration of O2 in elec trolyte mol cm−3

Ci

Concentration of O2 atr = R mol cm−3

Co

Concentration of O2 in electrolyte atr = δ mol cm−3

\(D_{{\text{o}}_{\text{2}} }\)

Diffusion coefficient of O2 in KOH cm2 sec−1

δ

Film thickness cm

E

Overpotential of the electrode V

F

Faraday's constant

i

Electrode current density A cm−2

ia

Current per agglomerate A

I1(Z)

First order Bessel function

I0(Z)

Zero order Bessel function

j

Local current density A cm−2

jo

Exchange current density A cm−2

L

Agglomerate length (catalyst thickness) cm

N

Number of electrons in rate determining step

Na

Number of agglomerates per cm2 of electrode

φ

Potential drop along ag glomerate V

φL

Potential drop at Lτa V

r

Radial direction

R

Radius of agglomerate cm

Ro

Gas constant

ρ

Density of platinum g cm−3

Sg

Surface area per gram cm2 g−1

\(S_{{\text{o}}_{\text{2}} }\)

Solubility coefficient of O2 mol cm−3

σm

Electrolyte conductivity (ohm cm)−1

T

Absolute temperature °K

τa

Axial tortuosity

θ

Porosity of platinum in the agglomerate

τr

Aadial tortuosity of the agglomerate

W

Catalyst loading g cm−2

x

Axial direction

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References

  1. [1]
    R. de Levie, ‘Advances in Electrochemistry and Electrochemical Engineering’,6, p. 329, Wiley, Interscience, New York (1967).Google Scholar
  2. [2]
    C. G. Austin and S. Almaula,J. Electrochem. Soc.,114 (1967) 927.Google Scholar
  3. [3]
    R. Brown, private communication.Google Scholar
  4. [4]
    L. A. Horve, private communication.Google Scholar
  5. [5]
    J. Giner and C. Hunter,J. Electrochem. Soc.,116 (1969) 1124.Google Scholar

Copyright information

© Chapman and Hall Ltd. 1972

Authors and Affiliations

  • P. D. Power
    • 1
  • M. J. R. Adams
    • 2
  1. 1.Unilever LtdLondon
  2. 2.3M Co. Ltd.UK

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