MEASUREMENT METHODS | Electrochemical: Impedance Spectroscopy

Electrochemical impedance spectroscopy is one of the most informative tools for investigating of the complicated processes in electrochemical power sources. The interest arises from the unique advantage of the method's capability to separate and characterize, in a single measurement, the different steps involved in a complex process. Impedance spectroscopy finds a variety of applications for studies of different energy sources – batteries, fuel cells, supercapacitors, and other systems – and has different targets – studies of basic kinetic processes, materials research, quality control, matching, and diagnostics. The principle of the method and a set of useful techniques providing for reliable experiments and data interpretation are described. The selection of the measurement setup configuration and details of the experimental program are discussed. Techniques for correction of the errors due to cable inductance and to possible time evolution of the object are described. The unique method for soft computing – differential impedance analysis, which corresponds to the nature of power sources – is also explained. Examples of experimental data – raw and processed – illustrate the recommended techniques and their application in different studies.