Also known as dielectric spectroscopy, electrochemical impedance spectroscopy is the process of measuring dielectric properties of an analyte or solution as a function of frequency. This process serves to elucidate the frequency response of the sample, such as energy storage, dissipation properties, impedance, and permittivity. EIS is also used to
identify information about reaction mechanisms such as the rate limiting step. It does this by displaying characteristic ionic relaxation, dipole relaxation, atomic polarization, electronic polarization, and dielectric relaxation.