Current-voltage characteristic electrolytic cell

The impregnation of porous nickel discs with CoPc was difficult because of the limited solubility of the chelate in the usual solvents. CoPc cathodes with carbon as substrate were therefore prepared for use in H2/O2 fuel cells. A mixture of 72 mg CoPc and 48 mg acetylene black, with PTFE as binder, was pressed into a nickel mesh of area 5 cm2. Electrodes of this type were tested in an H2/O2 fuel cell with 35% KOH electrolyte in an asbestos matrix at 80° C. Figure 5 compares the current/voltage characteristics of CoPc cathodes (14 mg/cm2) with those of other catalysts, including platinum (9 mg/cm2), silver (40 mg/cm2), and pure acetylene black (20 mg/cm2). An hydrogen electrode (9 mg Pt/cm2) was used as the anode in all tests. To facilitate comparison of the activity of different cathodes, the pure ohmic internal resistance of the cells (of the order of 0.02 ohm) was eliminated. 

Figure 11 Current-voltage characteristics for N3-dye-sensitized Ti02 solar cells under illumination and dark using the electrolyte with and without TBP.

Reichman, J. "The Current-Voltage Characteristics of Semiconnductor-Electrolyte Junction Photovoltaic Cells " Appl Phys Ltr, 36, p 574, 1980. 

Reichman J. (1980), The current-voltage characteristics of semiconductor-electrolyte junction photovoltaic cells , App/. Phys. Lett. 36, 574-577. 

By way of example, let us consider the simple electrolytic cell of Fig. 6.1.1, containing a motionless dilute binary metal electrolyte. We wish to determine the current-voltage characteristic of the cell, that is, the concentration polarization. To do this, we must calculate the flux of metal ions (cations) arriving at the cathode and depositing on it. As noted above, we assume that the overall rate of... 

From the current-voltage characteristic it is seen that the current is inversely proportional to the electrode spacing, since h. At low values of FV/RT the current is linear in the applied voltage, and at sufficiently high values it approaches the limiting current exponentially. This behavior is sketched in Fig. 6.1.2. The ideal electrolytic cell behavior will be modified with a real electrolyte as a consequence of dissociation of the solvent, say water, at sufficiently high voltages. This will result in a plateau and then a subsequent current increase, as sketched in Fig. 6.1.2. 

Figure 6.1.2 Current-voltage characteristic for an electrolytic cell (4 ° = 0).

With the ion concentration so determined the current-voltage characteristic can be obtained by integrating the equation for the potential distribution. Again, as in the case of the electrolytic cell, some care must be exercised with respect to the boundary conditions. In particular, the total potential drop must equal that in the dialysate half-channel, plus that in the concentrate halfchannel, plus the Donnan potential drop across the membrane. The Donnan potential drop arises from the discontinuities in concentration at the boundaries of the membranes (in this case, the cation exchange membrane for the half-cell as considered). The origin and expression for the Donnan potential are the same as for the electrode concentration overpotential. For the cation exchange membrane the Donnan potential drop is... 

The current-voltage characteristic of an electrolytic cell was analyzed in Section 6.1, where the solution contained between the copper electrodes was cupric sulfate. Suppose that the cupric sulfate solution is replaced by another electrolyte which is indifferent to the electrodes that is, no chemical reactions take place at the electrode surfaces. A constant potential difference is applied across the electrodes. Determine the potential and concentration distributions in the solution between the electrodes. 

Figure 6. Current-voltage characteristics of a single cell with supported YSZ electrolyte (top) and with supportedNi-cermet anode (bottom).

Electrochemical Characterization of Fuel Cells—Correlation Between EIS and Current/Voltage Characteristic of Fuel Cells. The performance of a fuel cell depends not only on electrochanical properties of the electrode/electrolyte... 

Koshida N, Nagasu M, Sakusabe T, Kiuchi Y (1985) The current voltage characteristics of a photoelectrochemical cell using p-type porous silicon. J Electrochem Soc 132(2) 346-349 Koshida N, Nagasu M, Echizenya K, Kiuchi Y (1986) Impedance spectra of p-type porous Si-electrolyte interfaces. J Electrochem Soc 133(11) 2283-2287 Mamykin AI, Moshnikov VA, Ilin AY (1998) Magnetic resonance spectroscopy of porous quantum-size structures. Semiconductors 32(3) 322-324... 

Fig. 10 Upper panel simulation of a current-voltage characteristic for a typical DSC (10 (un of mesoporous Ti02/electrolyte, 50 pm of pure electrolyte) with N719 dye. Lower panel dcmsily distribution (left) and current density (right) within the cell at 737 mV (close to open-circuit condition). The left picture shows all the charged species in the system electrons (free and trapped), iodide and triiodide, positive counter-i

Fig. 89. Current-voltage characteristic of a fuel cell with Zro.gs Cao.15 Oj.gs as solid electrolyte at 1000 °C for different fuel mixtures at the anode and oxygen at the cathode, a C3H8 H20 C02 = 1 3 1, b CaHg H20 C02 = 1 5 4, c H2 H20 = 35 1...

In the electrolytic cell, the cupric ions and sulfate ions both contribute to the conduction mechanisms. But only cupric ions enter into the electrode reaction and pass through the electrode-solution interface. The electrode therefore acts like a semipermeable membrane which is permeable to the Cu ions but impermeable to the 80 ions. Anions accumulate near the anode and become depleted near the cathode, resulting in concentration gradients in the solution near the electrodes of both ions. This is termed as concentration polarization. Let us determine the current-voltage characteristic of the cell, that is, the concentration polarization. To do this, we must calculate the flux of metal ions (cations) arriving at the cathode and depositing on it. We assume that the overall rate of the electrode reaction is determined by this flux. Once the cation distribution is known, the potential drop can be calculated. Note that anions are effectively motionless and do not produce a current. Let us assume that electrodes of the electrolytic cell are infinite planes at the anode (y = 0) and cathode (y = h) (Figure 6.3). The electrolyte velocity is zero. The definition of the current densities is... 

Figure 6.4 The current-voltage characteristic of the electrolytic cell...

A cost effective experimental setup for optical modulettion experiments, recently built in our laboratory. Is shown in Fig. 8 (57). Similar setup was recently reported by Tian et al. (58). Experiments performed with this system include photoreflectance (PR), electrolyte electroreflectance (EER), surface photovoltage spectroscopy (SPV), 1st. and 2nd. harmonics photoinduced current-voltage characteristics, spectral response and d.c. current-voltage characteristics. One can switch electronically between experiments and perform any number of techniques without moving the cell or removing the electrode from the electrolyte. A variable neutral... 

Fig. 11 Current voltage characteristics as a function of processing technique for operating temperature 800 C. The processing technique SP-VI shows the best cell performance ( 1 A/cm ), referred to as the optimized combination of processing techniques and subsequent co-firing of zirconia electrolyte + anode functional laver + anode support (Basu et al. 2005).

Transient absorption spectroscopy was employed to study electron-transfer dynamics in solar cells incorporating the polymer electrolyte based on EO copolymers with and without plasticizer. Electron-transfer kinetics were collected as a function of electrolyte composition, white light illumination, and device voltage.The results were further correlated with the current/ voltage characteristics of the solar cells. There are two main recombination pathways which can cause loss in DSSC efficiency electrons injected into the T102 conduction band can recombine with either dye cations or with the redox electrolyte (equations 10.8 and 10.9, respectively). 

Deviations from this model can be interpreted in terms of a voltage dependent loss of charge separation yield due to either lower electron injection yields or kinetic competition between charge recombination (equation 10.8 and 10.9) and equation 10.10. The first two terms on the right of equation 10.11 compose the usual non-ideal one diode current-voltage characteristic of a solar cell. The final term in equation 10.11 is a light-dependent recombination current, and is required to describe adequately the observed behavior for the cells assembled with the polymer electrolyte with and without plasticizer. 

Magnesium-air air cells with NaCl-electrolyte were developed and investigated. The current-voltage and the discharge characteristics of the cells with were studied. Air gas-diffusion electrodes suitable for operation in NaCl-electrolytes were designed. Various carbon-based catalysts for the electrochemical reduction were tested in these air electrodes. Magnesium alloys suitable for use as anodes in Mg-air cells were found. 

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