Figure 2.

Cyclic voltammetry at 400 rpm showing the effect of adding poloxamine suppressor to the 1.25 mol/L CuSO₄ −0.25 mol/L CH₃SO₃H-1 mmol/L KCl electrolyte. Without any suppressor, little hysteresis is evident between the reductive and oxidative directions of the scan, and significant Cu reduction occurs at a far less negative potential compared with solutions containing poloxamine Tetronic 701. As the poloxamine is added to the electrolyte, the onset of significant deposition that indicates suppressor breakdown shifts more negative, and increasing hysteresis is observed. The critical behavior of the suppression breakdown that underlies the S-NDR mechanism is hidden by the linear current-potential response associated with the impedance of the cell.