On the electrodeposition of titanium in ionic liquids

摘要: The ability to electrodeposit titanium at low temperatures would be an important breakthrough for making corrosion resistant layers on a variety of technically materials. Ionic liquids have often been considered as suitable solvents the electrodeposition titanium. In present paper we extensively investigated whether can electrodeposited from its halides (TiCl4, TiF4, TiI4) in different ionic liquids, namely1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]Tf2N), 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)amide ([BMP]Tf2N), and trihexyltetradecyl-phosphonium ([P14,6,6,6]Tf2N). Cyclic voltammetry EQCM measurements show that, instead elemental Ti, only non-stoichiometric are formed, example with average stoichiometries TiCl0.2, TiCl0.5 TiCl1.1. situSTM that—in best case—an ultrathin layer Ti or TiClx thickness below 1 nm obtained. addition, results both electrochemical chemical reduction experiments TiCl4 number these support formation insoluble cation–chloride complex species involving solvent. Solubility studies suggest that TiCl3 and, particularly, TiCl2 very limited solubility Tf2N based liquids. Therefore it does not appear possible reduce Ti4+ completely metal presence chloride. Successful deposition processing will require maybe tailor-made precursors avoid problems.