离子液体中钴的电沉积行为

在含有氯化钴的室温离子液体氯化1-甲基-3-乙基咪唑(EMIC)和乙二醇(EG)体系中研究了金属钴的电沉积. 循环伏安法测试表明, 在EMIC-CoCl2熔盐中, 乙二醇的加入促进了EMIC的解离, 从而使氧化还原电流增大, 在EMIC-CoCl2-EG体系中钴的电沉积是受扩散控制的非可逆电极过程, 在该电解液体系中, Co(II)在Pt电极上的传递系数α为0.30, 扩散系数D0为4.16×10^-6 cm·s^-1; 计时电流法研究表明, 钴在铂电极上的电结晶过程符合三维连续成核的生长机理; 场发射扫描电子显微镜(FE-SEM)观察镀层的微观形貌显示, 金属钴的结晶细小. XRD分析证实, 镀层为纯钴, 沉积的钴是晶态和微晶态的混合物, 并且晶粒尺寸为纳米级.

Electrodeposition Behaviors of Pure Cobalt in Ionic Liquid

The electrodeposition of metallic Co from a 1-ethyl-3-methylimidazolium chloride (EMIC) ionic liquid containing ethylene glycol (EG) and CoCl2 was investigated on copper substrates. Cyclic voltammogram indicated that the redox waves increased with increasing ethylene glycol content, because ethylene glycol accelerated the ionization of EMIC. The electrodeposition of metallic Co in EMIC-CoCl2-EG electrolyte was controlled by diffusion and irreversible growth process. At Pt electrode the cathodal transfer coefficient (α) and diffusion coefficient (D0) of Co(II) in EMIC-CoCl2-EG electrolyte were determined. Their values were obtained as follows: α=0.30 and D0=4.16×10^-6 cm·s^-1. Chronoamperometric results indicated that the electrodeposition of metallic Co at Pt electrode belonged to a three-dimensional progressive nucleation mechanism. The micromorphology of electrodeposits was observed by field emission scanning electron microscopy (FE-SEM). SEM images of the electrodeposits showed that the crystallite was small and compact. X-ray diffraction (XRD) approved that the obtained electrodeposits were pure cobalt. The results indicated that metallic Co electrodeposited from the 1-ethyl-3-methylimidazolium chloride ionic liquid containing ethylene glycol and CoCl2 was a mixed phase of crystalline and microcrystalline. The average size of cobalt crystalline grain was several tens nanometers.