ABSTRACT
Single Relaxation Time ............................................................. 340 12.5 Nyquist Plots of Model Systems ............................................................ 343 12.6 Equivalent Circuits for Real Systems .................................................... 345
12.6.1 Constant Phase Element (CPE) ................................................. 345 12.6.2 Warburg Element ...................................................................... 347
12.7 Impedance Related Functions: Immittances .......................................... 347 12.7.1 Complex Admittance ................................................................ 349 12.7.2 Complex Permittivity ................................................................ 350
12.7.3 Complex Electrical Modulus .................................................... 350 12.8 Extracting Bulk Resistance from the Nyquist Plots ............................... 351 12.9 Nyquist Plots and Immittance Formalisms of a Real System ................ 352 12.10 Conclusions ......................................................................................... 361 Keywords .......................................................................................................... 362 Acknowledgment .............................................................................................. 362 References ......................................................................................................... 362
12.1 IMPEDANCE SPECTROSCOPY (IS)
A brief discussion on applying IS to investigate the electrical properties of polymer electrolytes has been dealt with in Chapter 7. This chapter, on the other hand, aims to introduce and provide the necessary background for beginners to use IS as a method of analysis. Thus, we begin the chapter with the definition of impedance, and then discuss the basic principles of IS followed by impedance data presentation and interpretation. Ideal and real impedance data will be presented, compared and discussed in order to enable the readers to grasp a clearer picture on the electrical properties and electrochemical processes in a polymer electrolyte system.
