Annealing,solvation,and mirror-plating effects in phosphonium chloroaluminate ionic liquids  

作　　者：Zelei Zhang Atsushi Kitada Kazuhiro Fukami Kuniaki Murase 

机构地区：[1]Department of Materials Science and Engineering,Kyoto University,Kyoto 606-8501,Japan [2]Department of Chemical System Engineering,The University of Tokyo,Tokyo 113-8656,Japan

出　　处：《Nano Research》2023年第2期3348-3357,共10页纳米研究（英文版）

基　　金：supported by the Japan Society for the Promotion of Science(JSPS,No.22K14508:Z.L.Z.;No.22H01830:A.K.;No.20H05663:K.M.);the Joint Usage/Research Program on Zero-Emission Energy Research,Institute of Advanced Energy,Kyoto University(ZE2022A-01);Z.Z.also acknowledges the financial support of the Kyoto University Research Fund for Young Scientists(Start-up).

摘　　要：The physicochemical properties of a specific ionic liquid(IL)are naturally considered to be constant at a given temperature.However,a series of eutectic melts of trihexyl(tetradecyl)phosphonium chloride([P6,6,6,14]Cl)with aluminum chloride(AlCl3)is an exception.The viscosity of Al_(2)Cl_(7)−-dominated[P6,6,6,14]Cl–AlCl_(3)ILs(i.e.,AlCl_(3)mole fraction x=0.60–0.67)gradually increased as a function of annealing.Annealing also influenced the ultraviolet–visible spectra,nuclear magnetic resonance spectra,and the glass transition temperature of the ILs.Such annealing-induced variations in physicochemical properties were not observed in the AlCl4−-and Cl−-dominated ILs.In particular,the ionic conductivities of the ILs(x=0.60–0.67)were strongly decoupled from their viscosities during annealing.Ab initio calculations revealed the bending of the long tetradecyl chains in[P6,6,6,14]+coupled with Al_(2)Cl_(7)−,while neither Cl−nor AlCl_(4)−caused bending.In general,[P6,6,6,14]+-based ILs are recognized as sponge-like structures that consist of nano-scale polar and non-polar domains.We propose a gradual structurization process in Al_(2)Cl_(7)−-dominated ILs to account for their unusual physicochemical properties.Moreover,the addition of tetradecane,solvated in the non-polar domains of the ILs,substantially reduced the viscosity of the structured IL with x=0.67.Mirror Al electroplating is possible without a brightener,using the x=0.67 ILs,regardless of annealing or the admixture of tetradecane.

关 键 词：ionic liquid physicochemical property ab initio calculation electrodeposition 

分 类 号：TG14[一般工业技术—材料科学与工程]