A new electrochemical technique is described that involves applying a series of constant potential steps to an electrochemical cell. On each potential step the cell is permitted to attain quasi open‐circuit conditions by letting the current decay to a small, but finite, value. When small voltage steps are made, the voltage‐charge relation is a highly precise and accurate approximation to the thermodynamic properties of the cell. Application to the couple shows that the charge accumulated on each voltage step resembles an electrochemical potential spectrogram that provides evidence for the structural ordering of lithium in . The technique may be used to study the potential‐dependent cell kinetics, the thermodynamics of adsorption on surfaces, and the phase diagrams of cathode materials.