Electrodeposition of cesium at mercury electrodes in the tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide room-temperature ionic liquid

The electrochemistry of cesium was investigated at mercury electrodes in the tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide (Bu3MeN+Tf2N-) room-temperature ionic liquid (RTIL) by using cyclic staircase voltammetry, rotating disk electrode voltammetry, and chronoamperometry. The reduction of cesium ions at mercury exhibits quasireversible behavior with k(0) = 9.8 x 10(-5) cm s(-1) and alpha = 0.36. The diffusion coefficient of Cs+ in this RTIL was 1.04 x 10(-8) cm(2) s(-1) at 303 K. Bulk deposition/stripping experiments conducted at a rotating mercury film electrode gave an average recovery of 97% of the electrodeposited Cs. The density, absolute viscosity, and equivalent conductance of Bu3MeN+Tf2N- were measured over the range of temperatures from 298 to 353 K. A polynomial equation describing the temperature dependence of the density is presented. Both the viscosity and conductance exhibited the non-Arrhenius temperature dependence typical of glass-forming liquids. The ideal glass transition temperature and the activation energies for viscosity and conductance were obtained by fitting the Vogel-Tammann-Fulcher (VTF) equation to the experimental data for these transport properties. (C) 2004 Elsevier Ltd. All rights reserved.