混合离子液体中锌的电化学结晶及生长机理

在1-丁基-3-甲基咪唑氟硼酸盐和1-丁基-3-甲基咪唑氯化物组成的混合离子液体中,研究了锌在Pt,Cu,Fe-Ni基体上的电沉积过程.温度和ZnCl2的浓度等因素对锌电沉积的伏安行为会产生重要影响.计时电流实验表明,锌在上述3种基体上的电沉积涉及到扩散和动力学联合控制下的由2D瞬时成核到3D过程成核的晶核形成和生长过程.扫描电镜分析表明,高温和低浓度下,易形成线状或棒状的纳米沉积层;高浓度和较短的电解时间,将产生纳米颗粒的沉积物;高浓度和较长的电解时间,形成微米尺寸具有六方晶相的Zn沉积层.

Electrochemical Nucleation and Growth Mechanism of Zn from a Mixed Ionic Liquid

The electrodeposition of Zn on Pt,Cu and Fe-Ni alloy substrates is investigated in a mixed ionic liquid of 1-ethyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate.The voltage-current characteristics of zinc electrodeposition are significantly affected by temperatures and the concentrations of ZnCl2.Analysis of the chronoamperometric current-time transients suggests that the electrodeposition of zinc on above substrates described with transitions from instantaneous 2D to progressive 3D nucleation with mixed diffusion and kinetic controlled growth of the nuclei.Scanning electron microscopic analysis indicates that the deposits produced from plating baths with lower ZnCl2 concentrations and at higher temperatures exhibit nano-lines or nano-rods.The nano-size grain deposits are produced at higher temperatures and short electrolytic time,and it is also found that the micro-size hexagonal crystal deposits are formed with higher concentrations and at longer electrolytic time.