Electrochemical study and electrodeposition of manganese in the hydrophobic butylmethylpyrrolidinium bis((trifluoromethyl)sulfonyl) imide room-temperature ionic liquid

The electrochemistry of manganese was investigated at solid disk electrodes in the hydrophobic room-temperature ionic liquid butylmethylpyrrolidiniurn bis((trifluoromethyl)sulfonyl)imide (BuMePy-TFSI) by using staircase cyclic voltammetry and chronoamperometry. The Mn(II) species was introduced into the ionic liquid by anodic dissolution of the metallic manganese electrode. The reduction of Mn(II) ions at tungsten and platinum electrodes accompanies with nucleation mechanism and the coupled oxidation wave encounters kinetic hindrance that results in incomplete reoxidation of Mn electrodeposits. The density and absolute viscosity of BuMePy-TFSI were measured over a temperature range from 301.0 to 348.0 K. A polynomial equation describing the temperature dependence of the density is presented. The viscosity exhibits the Arrhenius temperature dependence and the relevant equation is provided. The manganese coatings were prepared by electrodeposition at several substrates. The surface morphology and X-ray diffraction patterns of these deposits were studied by scanning electron microscopy and powder X-ray diffraction spectroscopy, respectively. The as-electrodeposited manganese coatings were amorphous; however, alpha-phase manganese was observed after the deposits were annealed under 723 K for 1. day. (c) 2007 Elsevier Ltd. All rights reserved.