Current-voltage characteristic cathode layer

The complete current-voltage characteristics of the sensor can be derived from the similar consideration that was used for derivation of the i-E curve for liquid electrolytes. Because the potentials at each electrode are reversible, their difference can be expressed by the Nernst equation for the concentration of oxygen at the anode Co(0) and at the cathode Co (A). The current flowing through the layer generates a voltage drop iRb, where Rb is the bulk resistance of the ZrC>2 layer. 

Figure 12.2 Current-voltage characteristic obtained in a 50-cm dihydrogen/air fuel cell at 353 K at a total pressure of 150kPa. The anode and cathode layers consist of about 50wt% Pt/C [0.4/0.4mgp(/cm (anode/cathode)] and ionomer (ca. 900 EW ionomer/carbon ratio = 0.8 1). Circles, experimental data triangles, mass-transport-free AEceii squares, mass-transport-free and ohmically corrected AEceii- The current density is referred to the geometric surface area of the MEA. (From ref. 4, with permission from Elsevier.)...

The total current density in the cathode vicinity is close to the current density of positive ions, which results in the Engel-Steenbeck current-voltage characteristics of the cathode layer ... 

Voltage F, electric field A, and cathode layer length d are presented in Fig. 4-26 as functions of ctrrrent density, which is called the dimensionless current-voltage characteristic of a cathode layer. According to (4-37) ary cttrrent densities are possible in a glow discharge. In reality, a cathode layer prefers to operate at the only value of current density, the normal one jn (4-36), which corresponds to a minimttm of the cathode potential drop. It can be... 

Subsequent deployment of the new catalyst in the cathode layer of small-area MEAs first, then large-area MEAs, and finally fuel cell stacks represents the typical series of performance tests to check the practical viability of novel ORR electrocatalyst materials. Figure 3.3.15A shows the experimental cell voltage current density characteristics (compare to Figure 3.3.7) of three dealloyed Pt-M (M = Cu, Co, Ni) nanoparticle ORR cathode electrocatalysts compared to a state-of-the-art pure-Pt catalyst. At current densities above 0.25 A/cm2, the Co- and Ni-containing cathode catalysts perform comparably to the pure-Pt standard catalyst, even though the amount of noble metal inside the catalysts is lower than that of the pure-Pt catalyst by a factor of two to three. The dealloyed Pt-Cu catalyst is even superior to Pt at reduced metal loading. 

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