Projection of charge and discharge curves at constant current by impedance spectroscopy

A method to calculate charge and discharge curves of an electrochemical cell from the impedance data is described, and its validity is examined by measuring an impedance together with charge and discharge curves of a lithium cell with a high-area carbon electrode. The capacity to store and deliver electricity and the polarization voltage were well illustrated from the impedance spectroscopic data via a computational transformation. Since a method is a reversible conversion from a frequency domain to a time domain by the Fourier transform, impedance spectroscopic data are also obtained from the steady-state charge and discharge curves. A significance of introducing this complemental method to impedance measurements of the electrochemical cells especially in frequencies from mu Hz to 1 Hz is described.