Manganese and bismuth electrodeposition from a choline chloride based deep eutectic solvents
Résumé
The effect of different additives on manganese and bismuth electrodeposition from choline chloride-urea
(Reline) and choline chloride-ethylene glycol (Ethaline) deep eutectic solvents (DESs) was investigated. Spectroscopic and thermal studies were performed on the latters in order to understand whether some additives affect the DESs behaviors. the results of the thermal study do not indicate any significant change except a small shift in the melting point of the reline when adding ammonium chloride (~+3°C) and the modification of a cold crystallization peaks at low scan rate. The electrochemical behaviors of manganese and bismuth were then studied by cyclic voltammetry. electrocrystallization was studied by chronoamperometry which has shown that the bismuth electrodeposition evolves with a 3D progressive nucleation. The current transients for Mn reveals that the presence of thiourea enhances the nucleation rate by modifying the corresponding nucleation and growth model from 3D progressive to 3D instantaneous. EDS analysis confirms that pure bismuth thin films were obtained and X-Ray diffraction indicates that the bismuth growth follows a preferential orientation along the (012) reticular plane. While for manganese, no metal phase was observed in diffraction due to the amorphous nature of Mn deposits. Annealing treatments will therefore be necessary.