Promoting uniform zinc coatings through the use of quaternary ammonium salts based on phthalimide as electroplating additives†

Five quaternary ammonium salts derived from phthalimide compounds (PI1 to PI5) were synthesized and used for the first time as additives in zinc electroplating. Electrochemical experiments and theoretical calculations identified PI4 as the most effective compound for inhibiting zinc deposition and enhancing electrode adsorption among these compounds. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Diffraction (XRD) confirmed that PI4 significantly improves the uniformity and compactness of the zinc coatings. Moreover, the role of PI4 in zinc electroplating was elucidated. It reduces the interfacial tension between the electroplating solution and the substrate surface, facilitating uniform deposition of metal ions on the substrate, thus resulting in smoother and more adherent coatings. This study provides insights for future research on aqueous zinc-ion batteries, particularly regarding zinc anodes, and also provides a way for sustainable development.