The electric current response to the electrode potential perturbation contains much information about the electrochemical interface. Electrochemistry offers different methods for deriving the information with perturbations of different kind applied under stationary and nonstationary conditions. The potentiodynamic methods involve observation and analysis of the current or other dependent variables of an electrochemical interface as functions of the potential, while the latter is varied at a constant, known rate. Cyclic voltammetry, the basic potentiodynamic method, acquires and analyzes just the dependence of the current on the potential in the cyclic potential scan, while the potentiodynamic electrochemical impedance spectroscopy (PDEIS) [1-3] obtains much more information from the further analysis of the variable frequency response acquired with lowamplitude multi-frequency probing at each small step (typically one or two millivolt) of the quasilinear cyclic potential scan.     Similarly to potentiodynamic and stationary voltammetry, the potentiodynamic and the stationary versions of impedance spectroscopy give different information about the object. The PDEIS technique is especially helpful for the investigation of the processes which cannot be observed in stationary state, such as surface limited reactions, e.g. the underpotential deposition (upd) [3,4]. Different objects, processes (interfacial charge transfer, diffusion, adsorption, etc.) or structures (electric double layer at the electrochemical interface, surface space charge layer in semiconductor, etc.), are distinguished by their characteristic frequency response in PDEIS the similar way as they are distinguished in the stationary EIS, but the frequency response analysis in PDEIS gives the potentiodynamic profiles (dependencies on the variable potential) of the constituents of the frequency response [5]. The potentiodynamic profiles provide additional convenience in the characterization of interfaces, e.g. the space charge layer capacitance dependence on the potential gives immediately the Mott-Schottky plot which characterizes the semiconductor flat band potential and doping density, the double layer capacitance dependence on the potential discloses the potentials of deposition and dissolution of an atomic adlayer in the upd, the charge transfer resistance and Warburg coefficient dependences on the potential characterize, correspondingly, the kinetics and mass transfer in electrochemical reactions. PDEIS is also helpful for the characterization of pseudocapacitances of supercapacitors and distinguishing them from false capacitances which result from faradaic responses of surface limited electrochemical reactions.