Electrochemical Behavior of Copper Electrodeposition in BMIMPF6 Ionic Liquid

The ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) was synthesized by methylimidazol, chlorobutane and potassium hexafluorophosphate through two-step process. Then the electrochemical behavior of copper electrodeposition in BMIMPF6 IL was studied. The electrochemical oxidation and reduction process of copper ions were analyzed by cyclic voltammetry (CV) method, and the kinetic parameters and reversibility were also discussed. The nucleation and growth mechanism of copper on the substrate were investigated by chronoamperometry test. The micro-morphology and composition of the layer were characterized by scanning electron microscope (SEM), energy dispersire spectrometer (EDS) and X-ray diffractoneter(XRD). The results show that the redox of copper in the system is an irreversible process. The first stage of reduction is a reversible process and the third step in the second stage is an irreversible process, and the diffusion coefficient of this step is 3.743x10(-6) cm(2)/s. The electrocrystallization mechanism of copper in this system is three dimensional instantaneous nucleation growth controlled by diffusion. The copper layer is deposited in the form of graniphyric after nucleation.