Impedance spectroscopy background

This book is intended to provide a background and training suitable for application of impedance spectroscopy to a broad range of applications, such as corrosion, biomedical devices, semiconductors and solid-state devices, sensors, batteries, fuel cells, electrochemical capacitors, dielectric measurements, coatings, elec-trochromic materials, analytical chemistry, and imaging. The emphasis is on generally applicable fundamentals rather than on detailed treatment of applications. The reader is referred to other sources for discussion of specific applications of impedance. ... 

The result of impedance spectroscopy for NC specimen (18hr passage of C Hj gas) measured at room temperature 20°C is shown in a Cole-Cole plot in Figure 12.34. The measured conductivity dispersion also shows an initial increase of conductivity with increasing CNP concentration. The bulk conductivity estimated from data is 4 x 10 S/cm, which is 25 times higher than that of pure background material. 

Potential modulation techniques are used frequently in electrochemistry. The most well-known potential modulation electrochemical technique is a.c. impedance spectroscopy, in which current modulation caused by a potential modulation is analyzed. The potential modulation technique has also been used for in-situ IR spectroscopy (EMIRS and SNIFTIRS), but its use was aimed only to subtract the solution background and to enhance the S/N ratio of the spectram. If the IR signal caused by a potential modulation is analyzed, some information on electrode dynamics could be obtained as in a.c. impedance spectroscopy. 

Impedance Spectroscopy is a widely used and interesting measurement method applied in many fields such as electrochemistry, material science, biology and medicine. In spite of the apparently different scientific and application background in these fields, they share the same measurement method in a system identification approach and profit from the possibility to use complex impedance over a wide frequency range and providing interesting opportunities for separating effects, accurate measurements and simultaneous measurements of different and even non-accessible quantities. 

De Levie [1963,1964] was the first, it seems, to examine the frequency response of a wire-bmsh electrode of the above kind and provide the background mathematical treatment required to interpret the experimental behavior. The important aspect of the observed impedance spectroscopy over a wide range of frequencies was that transmission-line (Figure 4.5.22e) behavior resulted, as illustrated in Figure 4.5.30. The characteristic behavior is a linear complex-plane plot having a 45° phase-angle... 

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