Unveiling nucleation dynamics of gallium in DMF non-aqueous electrolytes: substrate effects and potential-dependent growth mechanisms

Gallium electrodeposition is currently limited by hydrogen evolution reactions (HER) in traditional electrolyte, which severely degrade current efficiency and deposit quality. This study investigates the electrodeposition of gallium (Ga) in a non-aqueous dimethylformamide (DMF) system containing 0.5 M GaCl₃ to eradicate HER and enable high-quality Ga deposition. Gallium deposits on different substrates exhibit distinct morphologies, among which the gallium particles deposited on copper substrates possess both spherical and strip-like structures. Through the analysis of the electrodeposition behavior and nucleation process of gallium on copper foil, an irreversible Ga deposition process with a cathodic charge transfer coefficient (α) of 0.0528 and a diffusion coefficient of 6.964 × 10⁻⁶ cm²/s, is confirmed during the electrochemical behavior and nucleation. The Ga nucleation shifts from an instantaneous model at -1.1 V to a progressive model at more negative potentials, reflecting potential-dependent growth dynamics. The deposition efficiency of gallium has been calculated to over 80% at low current density through the gravimetric method. These findings establish DMF as a promising solvent for efficient Ga electrodeposition, offering insights for applications in flexible electronics and energy storage technologies.