For any type of fuel cell (including a DPFC) for which reaction rate is the dominant process throughout the entire polarization curve, the [DELTA][[PHI].sub.cell] ordinate of the polarization curve should decrease and approach the limiting current density, j, (abscissa of the polarization curve) asymptotically.
The difference is that DPFCs are near their limiting current density at 100 mA/[cm.sup.2].
The reason for this is that metal ions cannot be reacted faster than they can arrive at the cathode surface, which is called the limiting current density. The limit is set by the plating process parameters.
 have declared that the IJE both enables a fast deposition rate because of a rise in the limiting current density and provides the volume fraction control of particles by changing the jet velocity.
So, in this study the value of limiting current density was determined experimentally.
The effect of jet velocity on limiting current density in Ni jet electroplating is shown in Fig.5.
Current density and limiting current density (LCD) of an ED cell is a function of a series of parameters, for example, physical (cell geometry, flow dynamics, spacer spacing, solution density, and viscosity) and chemical (ion concentration, transport number, and diffusivity) for a given set of membrane pairs.
As long as the ED operation is executed below limiting current (surface concentration becomes zero), the surface concentration on either side can be estimated from bulk concentration measurement (diluate/concentrate), current density, and limiting current density using (14) and (15) [19, 24]:
Estimation of Current Density and Limiting Current Density (i and [i.sub.j,lim]).
Afonso, "Limiting current density in the electrodialysis of multi-ionic solutions," Journal of Membrane Science, vol.