potentiometry potentiostatic electrochemical impedance spectroscopy impedance spectroscopy with constant applied potential A potentiometry where the change in impedance of an electrochemical cell is measured while maintaining a constant applied potential and the impedance is determined over a range of frequencies by analyzing the voltage-to-current ratio and the phase shift of the AC response. PEIS potentiostatic EIS As an electrochemical technique for measuring and characterizing batteries and E-chem cells. CHMO:0002934