Institute of Particle Technology, Arnold-Sommerfeld-Strasse 6, D-38678 Clausthal-Zellerfeld, Germany.
Phys Chem Chem Phys. 2010 Feb 28;12(8):1724-32. doi: 10.1039/b923527m. Epub 2010 Jan 28.
In this discussion paper we discuss our recent results on the electrodeposition of materials and in situ STM/AFM measurements which demonstrate that ionic liquids should not be regarded as neutral solvents which all have similar properties. In particular, we focus on differences in interfacial structure (solvation layers) on metal electrodes as a function of ionic liquid species. Recent theoretical and experimental results show that conventional double layers do not form on metal electrodes in ionic liquid systems. Rather, a multilayer architecture is present, with the number of layers determined by the ionic liquid species and the properties of the surface; up to seven discrete interfacial solvent layers are present on electrode surfaces, consequently there is no simple electrochemical double layer. Both the electrodeposition of aluminium and of tantalum are strongly influenced by ionic liquids: in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py(1,4)]TFSA, aluminium is obtained as a nanomaterial, whereas in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [EMIm]TFSA, a microcrystalline material is made. Tantalum can be deposited from [Py(1,4)]TFSA, whereas from [EMIm]TFSA only non-stoichiometric tantalum fluorides TaF(x) are obtained. It is likely that solvation layers influence these reactions.
在本讨论文件中，我们讨论了我们最近在材料电沉积和原位 STM/AFM 测量方面的结果，这些结果表明，离子液体不应被视为具有相似性质的中性溶剂。特别是，我们关注的是金属电极界面结构（溶剂化层）随离子液体种类的变化。最近的理论和实验结果表明，在离子液体体系中，常规的双电层不会在金属电极上形成。相反，存在多层结构，其层数由离子液体种类和表面性质决定；在电极表面上存在多达七个离散的界面溶剂层，因此不存在简单的电化学双电层。铝和钽的电沉积都受到离子液体的强烈影响：在 1-丁基-1-甲基吡咯烷双（三氟甲磺酰基）酰胺，[Py(1,4)]TFSA 中，铝得到纳米材料，而在 1-乙基-3-甲基咪唑双（三氟甲磺酰基）酰胺，[EMIm]TFSA 中，得到微晶材料。钽可以从[Py(1,4)]TFSA 中沉积，而从[EMIm]TFSA 中只能得到非化学计量的钽氟化物 TaF(x)。很可能溶剂化层影响这些反应。
