Electrochemical reaction orders charge transfer resistance

Determination of electrochemical reaction orders from the charge transfer resistance... 

With this model, the equilibrium potential is represented by the ideal voltage source (P eiectrode) the contribution of the electrolyte is represented by a resistance (i eiectroiyte) the behavior of the double layer (explained in Appendix 2.10) is associated with the capacity Cdi the kinetics of the electrochemical reaction is described by the charge transfer resistance (i ct) and finally the phenomenon of diffusion is modeled by the Warburg impedance (Zw). In order to take account of the connections, we introduce an ohmic resistance (i comection) and an inductance (Zconnection)- The details of these elements are presented below ... 

Faradic impedance (//) is directly related to the rates of charge transfer reactions at and near the electrode/electrode interface. As shown in Figure 3.1, the Faradaic impedance acts in parallel with the double-layer capacitance Cd, and this combination is in series with the electrolyte resistance Rei The parameters Rei and Cd in the equivalent circuit are similar to the idea of electrical elements. However, X/ is different from those normal electrical elements because Faradaic impedance is not purely resistive. It contains a capacitive contribution, and changes with frequency. Faradaic impedance includes both the finite rate of electron transfer and the transport rate of the electroactive reagent to the electrode surface. It is helpful to subdivide Zj into Rs and Cs, and then seek their frequency dependencies in order to obtain useful information on the electrochemical reaction. 

The overpotentials at the anode qAnode (oxygen overpotential) and cathode qcathode (hydrogen overpotential), also referred to as charge transfer overpotentials, result from the inhibition of electron transport in the separate electrochemical reactions (see Fig. 11.2). In order for current to flow through the electrolysis cell, the resistance polarization must also be overcome. It is caused by the ohmic resistance of the ceU (electrolytes, separator and electrodes). The ohmic voltage drop can be calculated from the current density i in A cm and the surface-specific resistance R of the ceU in Q cm. ... 

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