Electrodeposition of Copper and Copper‐Aluminum Alloys from a Room‐Temperature Chloroaluminate Molten Salt

Abstract

The electrodeposition of copper and copper-aluminum alloys was investigated in the Lewis acidic aluminum chloride-1-methyl-3-ethylimidazolium chloride (60.0-40.0 mol %) molten salt containing electrogenerated Cu(I) at 40 1°C.Sampled current and rotating ring-disk electrode voltammetry experiments indicated that it was possible to produce Cu-Al alloy deposits at potentials positive of that corresponding to the electrodeposition of bulk aluminum (-0 V). For a 5.0 x io mol L solution of Cu(I), the onset of the aluminum codeposition process was found to occur at around 0.30 V vs. the Al(III)/Al couple; however, a limiting current for the reduction of Cu(I) to pure copper metal can be observed in the 0.60-0.30 V potential interval in this solution. The Cu-Al alloy composition was found to be independent of the Cu(I) concentration, reaching a maximum value of 43 percent atomic fraction aluminum at 0 V. The surface morphology of bulk Cu-Al alloy electrodeposits was highly dependent on the aluminum content; pure copper deposits had a dense, nodular appearance, whereas deposits containing appreciable amounts of aluminum consisted of fragile dendrites. X-ray diffraction studies indicated that Cu-Al deposits containing about 7.2 percenter atomic fraction Al retained the face-centered cubic (fcc) copper structure; however, deposits containing 12.3 percent atomic fraction Al were two-phase with the second phase tentatively identified as martensitic 3'-Cu3A1. This phase appears to form before fcc copper becomes saturated with aluminum.

Chromium electrodeposition from [BMIm][BF4] ionic liquid

“…The majority of works on electrodeposition of metals have focused on imidazolium due to a wide potential window [12,13]. The potential window decreases in the presence of water because water molecules will aggregate making hydrogen evolution easier at the electrode surface.…”

Rechargeable aluminum batteries with conducting polymers as positive electrodes

“…AlCl 3 :EMIC mixtures with a molar ratio greater than 1:1 were purified as follows with an electrochemical stripping/plating procedure similar to the electrolysis procedure employed by Tierney et al 31 A two-electrode cell was assembled by immersing two pieces of aluminum foil (2-3 cm 2 each) into the mixture. Continuous plating onto the working electrode was performed at room temperature by galvanostatic hold (−5 or −10 mA) with a Princeton Applied Research 263A potentiostat/galvanostat.…”

Electrodeposition of Metals in Ionic Liquids

“…In the case of a basic BPCl-AlCl 3 ionic liquid, NiCl 2 dissolves and forms a divalent nickel chlorocomplex anion, NiCl 2À 4 , which cannot be reduced to metallic Ni [46]. The electrodeposition of copper, Cu, has been studied in MPCl- [49], BPCl- [50], EMICl- [22,37,38,[51][52][53][54], and BMICl-AlCl 3 [55] ionic liquids. In the case of acidic ionic liquids, it is possible to introduce monovalent and divalent copper species, Cu(I) and Cu(II), by dissolving copper chloride and dichloride, respectively, and by the anodic dissolution of metallic copper.…”

“…Metallic Cu can be obtained by the reduction of Cu(I). The formal potentials of Cu(I)/Cu in an acidic MPCl-, BPCl-, EMICl-AlCl 3 are reported as 0.777 [49], 0.784 [50], and 0.837 [52] V, respectively. Cu(I) can be also obtained by the reduction of Cu(II), of which the formal potentials in the acidic MPCl-and BPCl-AlCl 3 are reported as 1.851 [49] and 1.825 [50] V, respectively.…”