二氯甲烷和甲苯对咪唑离子液体结构和性质及铝电沉积的影响  

Effect of dichloromethane and toluene on the structure,property,and Al electrodeposition in 1-butyl-3-methylimidazolium chloroaluminate ionic liquid

作　　者：田国才[1,2] 袁青香 TIAN Guo-cai;YUAN Qing-xiang(State Key Laboratory of Complex Non-ferrous Metal Resources Clean Utilization,Kunming University of Science and Technology,Kunming 650093,China;Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室,昆明6500932 [2]昆明理工大学冶金与能源工程学院,昆明650093

出　　处：《工程科学学报》2021年第8期1037-1046,共10页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51774158,51264021);云南省中青年学术技术带头人后备人才培养资助项目(2011CI013)。

摘　　要：离子液体电沉积铝技术具有广阔的应用前景,而添加剂是提高铝镀层性能的有效方法,但相关作用机制还有待明确.本文应用量子化学和分子动力学模拟研究了二氯甲烷(DCM)和甲苯(C_(7)H_(8))对氯化-1-丁基-3-甲基咪唑/三氯化铝([BMIM]Cl/AlCl_(3))体系的微观结构、物理化学性质和铝电沉积的影响.发现DCM易与阴、阳离子形成氢键,分布在阴阳离子之间使得阴阳离子间距离增加、相互作用能减小,导致阴阳离子扩散能力增强、铝配离子更倾向以Al_(2)Cl_(7)^(-)形式存在,体系黏度降低电导率增加,因而对体系电化学性质提升很大,而且DCM起到了晶粒细化和整平作用,从而可以得到镜面光亮的沉积层,所得结果与实验值吻合较好.C_(7)H_(8)主要分布在阳离子周围,与阳离子有较强相互作用,在沉积过程中吸附于电极表面的凸出部分,抑制了电活性离子的还原而主要起到整平作用,其对阴离子和阳离子之间的相关作用的影响比DCM小,因而体系电化学性质提升不如DCM.The electrodeposition of aluminum in ionic liquid has broad application prospects,and additives are an effective way to improve the performance of the aluminum coating.However,the relevant mechanism behind this remains to be clarified.In the present work,the effects of dichloromethane(DCM)and toluene(C_(7)H_(8))on the microstructure,physicochemical properties,and aluminum electrodeposition with 1-butyl-3-methylimidazolium chloride/aluminum chloride([BMIM]Cl/AlCl_(3))were studied using quantum chemistry and molecular dynamics simulation.It is found that DCM easily forms hydrogen bonds with anions and cations of ionic liquids.Since DCM is distributed between anion and cation,the distance between the anion and cation increases,and the interaction energy decreases.As a result,the diffusion ability of anions and cations is enhanced,and the aluminum complex anions tend to exist in the form of.The viscosity of the system decreases,and the conductivity increases,so the electrochemical properties of the system are significantly improved,which are in good agreement with the experimental values.C_(7)H_(8) is adsorbed on the protruding part of the electrode surface in a flat way,which plays a leveling role and results in a flat white coating.Alternatively,DCM easily interacts with the electroactive ion Al_(2)Cl_(7)^(-),which makes it difficult to reduce this electroactive ion.At the same time,the concentration of the electroactive ion decreases as the concentration of the additive is increased,which leads to a large overpotential in the electrochemical process,resulting in a decrease in the electrode reaction rate that plays a role in grain refinement.Moreover,the interaction between DCM and cations is also strong,and they can be adsorbed on the protruding part of the electrode surface during the electrochemical process,playing a certain leveling role.Therefore,the addition of DCM can obtain specular gloss deposits.The effect of C_(7)H_(8) on the interaction between anions and cations is not as good as DCM,which consequently

关 键 词：离子液体 铝电沉积 添加剂 二氯甲烷 甲苯 第一性原理 分子动力学 

分 类 号：TF821[冶金工程—有色金属冶金]