Investigation of the anodic decomposition of the solid electrolyte RbCu₄Cl₃I₂

Abstract.

The process of electrochemical decomposition of the solid electrolyte RbCu₄Cl₃I₂ at a vitreous carbon electrode has been investigated. The anodic decomposition of the electrolyte occurs in two steps. At first, the oxidizing electrode reaction of Cu⁺ ions to Cu²⁺ ions takes place at potentials higher than 0.57 V and a layer of decomposition products is formed on the electrode surface, including the divalent copper compound RbCuCl₃. Then the oxidizing reaction of I^– ions occurs at potentials higher than approximately 0.67 V, with deposition of an iodine layer onto the electrode surface. The deposition rate of the layers of decomposition products is controlled by instantaneous nucleation and two-dimensional growth of the deposit. The total thickness of the passivating layer of decomposition products on the anode is equal to ca. 1 µm.