Impedance PEIS

R.J. Pei, Z.L. Cheng, E.K. Wang, and X.R. Yang, Amplification of antigen-antibody interactions based on biotin labeled protein—streptavidin network complex using impedance spectroscopy. Biosens. Bioelectron. 16, 355—361 (2001). 

Figure 18 Various models proposed for the surface films that cover Li electrodes in nonaqueous solutions. The relevant equivalent circuit analog and the expected (theoretical) impedance spectrum (presented as a Nyquist plot) are also shown [77]. (a) A simple, single layer, solid electrolyte interphase (SEI) (b) solid polymer interphase (SPI). Different types of insoluble Li salt products of solution reduction processes are embedded in a polymeric matrix (c) polymeric electrolyte interphase (PEI). The polymer matrix is porous and also contains solution. Note that the PEI and the SPI may be described by a similar equivalent analog. However, the time constants related to SPI film are expected to be poorly separated (compared with a film that behaves like a PEI) [77]. (With copyrights from The Electrochemical Society Inc., 1998.)...

In an IMPS experiment the light intensity is modulated to produce an ac photocurrent that is analysed to obtain kinetic information. An alternative approach is to modulate the electrode potential while keeping the illumination intensity constant. This method is called PhotoElectrochemical Impedance Spectroscopy (PEIS). 

EIS measurements can also be carried out under conditions where illumination of the semiconductor generates a photocurrent. The technique is then referred to as photoelectrochemical impedance spectroscopy, PEIS. Interpretation of the results in terms of passive RC circuit elements is no longer appropriate since the system contains a current source. A more satisfactory approach is to relate the impedance response directly to the physical processes responsible for the photocurrent (Ponomarev and Peter, 1995 Peter, 1999 Peter and Vanmaekelbergh, 1999). 

Relationship between IMPS and Photoelectrochemical Impedance Spectroscopy (PEIS)... 117... 

IMPS uses modulation of the light intensity to produce an ac photocurrent that is analysed to obtain kinetic information. An alternative approach is to modulate the electrode potential while keeping the illumination intensity constant. This method has been referred to as photoelectrochemical impedance spectroscopy (PEIS), and it has been widely used to study photoelectrochemical reactions at semiconductors [30-35]. In most cases, the impedance response has been fitted using equivalent circuits since this is the usual approach used in electrochemical impedance spectroscopy. The relationship between PEIS and IMPS has been discussed by a number of authors [35, 60, 64]. Vanmaekelbergh et al. [64] have calculated both the IMPS transfer function and the photoelectrochemical impedance from first principles and shown that these methods give the same information about the mechanism and kinetics of recombination. Recombination at CdS and ZnO electrodes has been studied by both methods [62, 77]. Ponomarev and Peter [35] have shown how the equivalent circuit components used to fit impedance data are related to the physical properties of the electrode (e.g. the space charge capacitance) and to the rate constants for photoelectrochemical processes. 

A comparison of this method with photoelectrochemical impedance spectroscopy" as applied to photoelectrochemical hydrogen evolution at p-lnP has been reported [728]. Intensity modulated photocurrent spectroscopy has been compared with intensity-modulated photo voltage spectroscopy (IMVS) [729]. Intensity modulated photocurrent spectroscopy has been applied in a study of the silicon dissolution in aqueous solutions of NH4F [730] and n-GaAs electrodes [731] a general review is available [732]. Photocorrosion of CdS has been investigated with IMPS and photoelectrochemical impedance spectroscopy (PEIS) [733] a mechanism could be de-... 

One can envision three types of perturbation an infinitesimally narrow light pulse (a Dirac or S-functional), a rectangular pulse (characteristic of chopped or interrupted irradiation), or periodic (usually sinusoidal) excitation. All three types of excitation and the corresponding responses have been treated on a common platform using the Laplace transform approach and transfer functions [170]. These perturbations refer to the temporal behavior adopted for the excitation light. However, classical AC impedance spectroscopy methods employing periodic potential excitation can be combined with steady state irradiation (the so-called PEIS experiment). In the extreme case, both the light intensity and potential can be modulated (at different frequencies) and the (nonlinear) response can be measured at sum and difference frequencies. The response parameters measured in all these cases are many but include... 

In the case of a semiconductor-based photoelectrochemical system, the measurement of the electrochemical admittance serves two purposes. As is explained in Sect. 2.1.3.1, it allows on the one hand the in situ determination of the energetics of the (bulk) semiconductor surface. On the other hand, it makes the dynamics of various (photo)electrochemical processes experimentally accessible. Clearly, EIS is also possible using an illuminated semiconductor, an experimental method sometimes referred to as PEIS. Finally, it should be noted that although the electrochemical admittance is determined experimentally (the applied electrode potential is used as the perturbation), the electrochemical impedance is generally plotted as the result of an EIS measurement. 

ABSTRACT We report on the microwave assisted hydrothermal synthesis of LiMnPO and LiCoPO and their electrochemical characterization by means of cyclic voltammetry and potentioelectrochemical impedance spectroscopy (PEIS/SPEIS). The influence of various synthesis parameters like pH-value and reaction time on the particle shape and size and thus on the electrochemical performance are studied. In addition, effects of the battery state of charge on the impedance spectra are investigated and discussed. 

FIGURE 10.23 Results comparison of all parts in every cell, (a) Electrochemically active surface area coefficient, (b) Average particle diameter values, (c) Contact angle values, (d) Impedance values. (Reprinted from Int. /. Hydrogen Energy, 35, P. Pei, X. Yiran, P. Chao. Analysis on the PEM fuel cells after accelerated life experiment, 3147-3151, Copyright (2010), with permission from Elsevier.)... 

---