Charge curve

Fig. 9. Discharge and charging curves for a sintered iron electrode at a constant current of 0.2 A where the apparent geometrical surface area is 36 cm and porosity is 65%. A and B represent the discharging and charging regions, respectively. Overall electrode reactions, midpoint potentials, and, in parentheses, theoretical potentials at pH 15 ate Al, n-Fe + 2 OH Fe(OH)2 + 2, 0.88 V (1.03 V) B, Fe(OH)2 FeOOH + H+ +, 0.63 V (0.72 V) C,...

Fig. 11. Constant-current charge curve for a high rate Ag—Zn ceU at room temperature. Charging carried out at the 10-h rate.

Figure 38. Discharge and charge curves for yip MnO, spinel LiMn204 and CDMO electrodes.

FIGURE 3-3 Variation of the charging (curve A) and diffusion currents (curves B) dining the lifetime of a drop. 

FIGURE 10.9 Galvanostatic charging curve for a platinized platinum electrode in 0.1 M H2SO4 solution (1) anodic scan, (2) cathodic scan. 

Toward the end of the 1950s, a number of workers developed methods to record potentiodynamic charging curves which proved to be convenient for electrodes with smooth surfaces but require complex equipment. Figure 10.10 shows a typical voltam-mogram measured at a smooth platinum electrode. Such vs. E curves are the... 

The galvanostatic and potentiodynamic charging curves of platinum electrodes shift approximately 60 mV in the negative direction when the solution pH is raised by 1 unit. This implies that when potentials which refer to the equilibrium potential of a hydrogen electrode in the same solution (RHE) are used, these curves remain practically at the same place within a wide range of solution pH. Hence, we shall use this scale while analyzing these curves. 

FIGURE 16.1 Charging curves recorded when an adsorbed layer of oxygen adatoms or a phase oxide layer are formed (a) galvanostatic (b) potentiostatic. 

Charging curves of a different type are recorded at certain metals Instead of the horizontal sections in the galvanostatic curves, sloping segments arise, the hysteresis between the anodic and cathodic segments is larger, and the current peaks in potentiodynamic curves are more diffuse. 

Figure 27.4 shows a charge curve for the cell when it was charged over a period of 12 hours from 3.0 to 5.2 V. During the charge, 16 XRD scans were collected continuously. The time at which each spectrum was acquired is shown in Fig. 27.4. The time for each scan was about 45min. The corresponding spectra are shown in Fig. 27.5. Four hexagonal phases, HI, H2, Ola, and Ol, were observed and their Bragg peaks were indexed in Fig. 27.5. The phase transition from HI to H2 started in scan 4 and...

FIGURE 27.4 First charge curve of an AljOj-coated LiCoOj/Li cell from 3 to 5.2 V at a 12-h rate. (From Liu et al., 2004, with permission from The Electrochemical Society.)... 

Recent studies of the processes of activation and deactivation111 have shown, as seen in Fig. 20, that the time dependences of the potential, upon the application of current steps, resemble those characteristic of porous film formation and that the differences are of a quantitative nature. The initial part, representing a typical galvanostatic charging curve (with the initial jump due to the... 

The capacitance determined from the initial slopes of the charging curve is about 10/a F/cm2. Taking the dielectric permittivity as 9.0, one could calculate that initially (at the OCP) an oxide layer of the barrier type existed, which was about 0.6 nm thick. A Tafelian dependence of the extrapolated initial potential on current density, with slopes of the order of 700-1000 mV/decade, indicates transport control in the oxide film. The subsequent rise of potential resembles that of barrier-layer formation. Indeed, the inverse field, calculated as the ratio between the change of oxide film thickness (calculated from Faraday s law) and the change of potential, was found to be about 1.3 nm/V, which is in the usual range. The maximum and the subsequent decay to a steady state resemble the behavior associated with pore nucleation and growth. Hence, one could conclude that the same inhomogeneity which leads to pore formation results in the localized attack in halide solutions. 

Figure 6. The galvanostatic discharge curves and self-charge curve for Zn-Air coin battery with PANI/TEG gas-diffusion electrode.

Figure 12. F cycle constant current charge curves of synthetic graphite LONZA KS 44 (i) using 1 MLiN(S02CF3)2 in EC.DME (dimethoxy ethane, CH3OCH2CH2OCH3) (3 2) as electrolyte. The measurement was stopped when the graphite was exfoliated, (ii) using 1 M LiN(S02CF3)2 in EC F-DME (partially fluorinated dimethoxy ethane, CH3OCF2CF2OCH3) (3 2) as electrolyte, i = 20 mA g1, cut-off = 0.0 V vs. Li/Li+ (adaptedfrom [12]).

Figure 6. The first charge curves of Hohsen Carbon-Type material modified with Co-Ni complex. Annealing temperatures are shown in the figure. Rate 0.1 C (10 hours).

Figure 3. Theoretical surface charge curves for a hypothetical surface with Ns = 8 x 1014cm-2, pHp = 7, Ceaticn = 150 n /cm2, Canion = 75 pF/cm2, and c = 0.1 mol/dm3. Kcane = Kanion = 100 to 0.01.

Fig. 11.13 Typicsil discharge-charge curves of the cell Li/Li20-V205-Si02/MnQt at room temperature (Ohtsuka et d., 1990).

Figure 10.9. Anodic charging curves from 0.4 V during the galvanostatic transients anodic potential sweep at 91 mA/cm in 1N HCIO4 (curve a) and in 1N HCIO4 + HCOOH (curve b). (From Ref. 3, with permission from the Electrochemical Society.)...

Acid/hase potentiometry enables the surface charge density to be measured. This involves comparison of the titration curves obtained for the suspension of oxide at several different ionic strengths (10 10" M) with that of the electrolyte alone, followed by calculation of the net consumption of protons or hydroxyl ions (mol g ) at each pH. The data is presented as a plot of excess of acid or base (Fh - Toh ) mol g or mol m ) vs pH (adsorption isotherm) or as a plot of surface charge, cr, (coulombs m ) vs pH (charging curve) (Figure 10.5). 

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