BMIMPF_6离子液体中铜沉积的电化学行为

Electrochemical Behavior of Copper Electrodeposition in BMIMPF_6 Ionic Liquid

首先通过两步法,以甲基咪唑、氯代正丁烷和六氟磷酸钾为原料合成了基础液1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF_6),然后向基础液中加入氯化铜,研究了铜电沉积的电化学行为.采用循环伏安测试法研究了二价铜离子在该体系中的氧化还原电化学历程,并分析了其动力学参数及可逆性.采用计时电流测试法研究了该体系中铜的形核生长机制.使用扫描电子显微镜[SEM(配置能谱仪,EDS)]及X射线衍射仪(XRD)对该体系中沉积层的生长形貌及成分进行了分析.结果表明,铜在该体系中的氧化还原为非可逆过程,其中第一还原阶段为可逆过程,第二阶段的第三步为不可逆过程,其对应的扩散系数为3.743×10^(-6)cm^2/s;该体系中铜的电结晶机理为受扩散控制的三维瞬时形核生长;铜沉积层在形核后堆积长大呈花斑状,形成铜单质沉积层.

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. 743×10～（-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.