Electrodeposition of tin in an amide type ionic liquid containing chloride ion

Abstract

Electrochemical behavior of Sn was investigated on a GC electrode in an aprotic ionic liquid, 1-butyl-1- methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing BMPCl and SnCl2 at 298K. SnCl2 was found to dissolve as [SnCl4]2- by potentiometry. The formal potential of [SnCl4]2-/Sn was -1.67V vs. Ag|Ag(I) (-1.24V vs. ferrocene|ferrocenium), which was more negative than that in BMPTFSA without chloride ions. Electrodeposition of Sn was possible by reduction of [SnCl4]2- in the ionic liquid. The dissociation of [SnCl4]2- was suggested from the diffusion coefficient of [SnCl4]2-. Tubular deposits with an inner diameter of 1-1.5μm were obtained in addition to granular deposits by potentiostatic cathodic reduction at -2.0V.