Electrochemical impedance spectroscopy Nyquist plot

Electrochemical impedance spectroscopy (EIS) profiles, measured as a function of the interrogating frequency, can be represented on both Bode and Nyquist plots. The two-component Bode plot presents a comprehensive and... 

Fig. 1 Representative a Nyquist and b Bode plots from electrochemical impedance spectroscopy measurements (HubrechtJ (1998) Metals as Biomaterials, Helsen J, Breme H (eds) John WUey Sons Limited. Reproduced with permission)...

Figure 5.4. Nyquist plots obtained at a DC bias potential of 0.2 V versus Ag/AgCl for electrodes with various amounts of catalyst ink applied [2], (Reprinted from Electrochimica Acta, 50(12), Easton EB, Pickup PG. An electrochemical impedance spectroscopy study of fuel cell electrodes, 2469-7, 2005, with permission from Elsevier.)...

Figure 2 Nyquist plots of the normalized impedance results of 15 x 8 x 8 supercells obtained from kinetic Monte Carlo (KMC) simulations at 400 K compared with the results from the electrochemical impedance spectroscopy (EIS) measurements on a pulsed layer-deposited polycrystalline thin film YSZ (100 nm in thickness) at 336°C. Reprinted from Reference [115], copyright 2007, with permission from Elsevier.

Figure 16.41 Electrochemical impedance spectroscopy (ECIS) Nyquist plot of Re-hn impedance curves at various stages during low-cycle flexure fatigue testing of woven GFRP (specimen failure occurred at 7000 cycles) [99].

Figure 14.12. Electrochemical impedance spectroscopy based in situ DNA sensing (A Nyquist plots and (B corresponding Bode plots of as grown, DNA probe against anthrax lethal factor (pLF -modified, and dsDNA-modified GaNNWs at different concentrations of LF targets (arrows indicate increasing concentration, in situ DNA hybridization detection. ...

When a range of frequencies is applied to the DUT, both El and ECI techniques are called spectroscopies, i.e., electrical impedance spectroscopy and electrochemical impedance spectroscopy. Electrochemical impedance spectroscopy (EIS) profiles, measured as a function of the interrogating frequency, can be presented by two popular plots complex plane impedance diagrams, sometimes called Nyquist or Cole-Cole plots, and Bode (I Z I and 6) plots (Fig. 2). As the impedance, Z, is composed of a real and an imaginary part, the Nyquist plot shows the relationship of the imaginary component of impedance, Z" (on the Y-axis), to the real component of the impedance, Z (on the X-axis), at each frequency. A diagonal line with a slope of 45° on a Nyquist plot represents the Warburg... 

Fig. 2 Representative (a) complex plane diagrams (Nyquist or Cole-Cole plots) and (b) Bode plots from electrochemical impedance spectroscopy measurements...

The use of electrochemical impedance spectroscopy (EIS) for the assessment of coatings has been under development for many years now [83]. The first period application of the technique was restricted to the study of the corrosion occurring with poorly protective coatings and coating impedances were evaluated by shape of the Nyquist plots. However, relatively few reports have been published describing results obtained from protective organic coating systems as used commercially [84]. 

ABSTRACT Electrochemical impedance spectroscopy is a measurement method for detailed investigations of electrochemical systems. The increasing number of recorded impedance spectra requires automated evaluations. Manual evaluations based on the visual comparisons of several impedance spectra in a Nyquist plot are subjective, time-consuming and thus no longer feasible. The challenge is to find quantitative, reproducible and therefore objective evaluation methods that coincide with visual impressions. 

TABLE 8.1 List of Common Circuit Elements Used in Equivalent Circuit Modeling for Nyquist Plots Generated from Electrochemical Impedance Spectroscopy. 

Electrochemical Impedance Spectroscopy (EIS) Applications to Sensors and Diagnostics, Fig. 2 Impedance data representations (a) Lissajous figure (b) complex impedance or Nyquist plot... 

Electrochemical Impedance Spectroscopy (EIS) as schematically shown in Eigure 3.10 requires an alternating current (AC) and the output is a Nyquist plot for charge-transfer or diffusion control process, which can be used to determine Rv, which in turn, is inversely proportional to the corrosion current density icorr-... 

In Chapter 3, electrochemical impedance spectroscopy (EIS) was introduced as a powerful technique for PEM fuel cell diagnosis. EIS measurement can be conducted at OCV and under load. The AECD of the ORR (fo ) can be calculated using Eqn (3.8), based on the simulated /f° (charge transfer resistance at the OCV for the ORR) from the Nyquist plot obtained by EIS that is shown in Fig. 3.12. The values of the membrane resistance (/fm), charge transfer resistance (/ t) and mass transfer resistance (/fmt) in a PEM fuel cell at different current densities can also be simulated using measured EIS, based on... 

The Electrochemical impedance spectroscopy (EIS) results for the Mg alloy without and with surface Al coated from the 53 m/o and the 60 m/o ionic liquid, respectively, are depicted in Fig. 14.10. For bare Mg alloy, the polarization resistance was about 470 Qcm. A substantial increase in the polarization resistance, as evidenced by an enlarged diameter of the semicircle of the Nyquist plot, can be obtained for Mg alloy if it is electroplated with Al. For those with surface Al electrodeposited at -0.2 V from the 53 m/o and the 60 m/o ionic liquid, the polarization resistance in 3.5 wt% NaCl solution are 3000 and 5200 Qcm, respectively. The results were consistent with those revealed in the polarization curves demonstrated in Fig. 14.8. The improved polarization resistance of AZ91D Mg alloy with Al coating from ionic liquid is clearly demonstrated. However, the passivity or the polarization resistance of the Al-coated Mg alloy depends on the deposition conditions. The Al film formed in more acidic AICI3-EMIC and at a lower deposition rate renders a better passivation behavior. 

Electrochemical impedance spectroscopy is useful in the evaluation of coatings, the elucidation of transport phenomena in electrochemical systems, and the determination of corrosion mechanisms and rates. Bode and Nyquist plots are the most common data output formats, and an example of each for a simple parallel-connected resistance-capacitance circuit are shown in Figs. 31.3, and 31.4, respectively. The Bode plot format shows the... 

Electrochemical impedance spectroscopy (EIS) is also commonly employed for analysis of enzymatic electrode systems [11], EIS is performed by overlaying a range of alternating current (AC) perturbation signals to an electrode that is under direct current (DC) bias. A Nyquist plot is then generated, and variations of the frequency response can then be used to interpret limiting mechanisms associated with charge transfer. 

Electrochemical impedance spectroscopy of a bare zinc specimen and of specimens coated with fluoro-organic compounds F-COOH(C5) and F-COF(C12) at a concentration of 1000 ppm in solution are shown as a Nyquist plot in Fig. 16.1. The plots for the specimens were almost semicireular or slightly semi-oval. The difference in impedance value at high and low frequency, that is, the diameter of this depressed semicircle, corresponds to the resistanee of the coating to corrosion. All specimens... 

Analysis of electrolytes based on P(EO-EM) + 20 wt% Lil, 2 wt% I2 and 70 wt% GBL with different CE contents (a) Nyquist plots of the electrochemical impedance spectroscopy and (b) ionic conductivity values. The crown ether structure is shown in the inset. 

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