Chronopotentiometric Analysis of the Anode Dissolution Process in Dimethyl Sulfone–Aluminum Chloride Electrolytic Solution

Abstract

Toward the commercialization of aluminum electrodeposition, unveiling the anode dissolution process in a sustainable electrolyte is essential. Herein, to gain more insight into the anode dissolution process in dimethyl sulfone (DMSO2)–aluminum chloride (AlCl3) electrolyte solution, we performed chronopotentiometry measurements using Pt disk electrodes. In this system, the anode dissolution reaction exhibits two-wave behavior with a positive potential shift of +1.0 V. The Coulombic efficiency, reaction potential, and multiple reverse chronopotentiometry measurements show that the second-stage anode dissolution reaction is a three-electron-transfer process from Al0 and AlCl4− to Al2Cl7−. The transition of the anode dissolution reaction from the first to the second-stage occurs because Al (DMSO2)33+ is not stably formed owing to DMSO2 depletion near the electrode during the anode dissolution reaction.