Polarization curve quasi-static characterization

There are no official norms as to how this polarization curve should be plotted. Thus, caution must be exercised when interpreting published versions of polarization curves, because the authors do not always take sufficient care in terms of specifying the conditions in which the data were obtained, which have a very great impact on the result. 

It is possible to plot this curve by hand , i.e. by gradually varying the current, and reading off the voltage, value by value. Automation of the plotting of the polarization curve, where possible, is rmdoubtedly preferable, because it minimizes the impact of the tester on the results obtained, and offers good reproducibility of the characterization. Two solutions are discussed in the next section one with cmrent stairway-type steps and the second with very-low-frequency current sweepings. 

This technique is in fact the direct automation of the manual plots described above, with the slight difference that the switch from one level of current to another is quicker (in extreme cases, there is a step a ramp in current is often adopted). The same switch can be strictly applied for all the changes. 

The lower the sweeping frequency (a few mHz), the better the operating conditions will be able to adapt to the level of current. For low frequencies (a few 100 mHz), this needs to be examined on a case-by-case basis. 

It is also possible to use a triangular current. There are few differences between a sinusoidal sweeping and a triangular sweeping, exception at the extremities of the 

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Yet what interests an electrical engineer wishing to integrate an electrochemical component into a generator is its component as a whole cell, given that an electrode does not work on its own. The quasi-static function of such a component is therefore characterized by the polarization curve, i.e. the relation linking the difference in... 

Recently, a method for the analysis of the DPP curves arising from slow electrode reaction has been presented [68, 69]. The influence of the first polarization time, of the pulse duration and potential step amplitude on the recorded current was clearly manifested. The solution may be applied to the static as well as to the dropping mercury electrodes. It was verified for the quasi-reversible system Cd(Hg)/Cd(II) in the presence of 2-(a-hydroxybenzyltriamine), a substance of biological interest. Also the irreversible system Cr(VI)/Cr(III) in NaOH medium (characterized by k° 10" m s" ) was followed according to this concept. 

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