Electrochemical and transport properties of ethaline containing copper and tin chloride

Electrochemical and transport properties were measured for hydrated chloride salts of copper and tin in ethaline, which is a 1 : 2 ratio of choline chloride and ethylene glycol. Density, viscosity and conductivity for ethaline melts with different salt concentrations have been measured for temperatures between 293 and 328 K. The change in formal potential with changing metal ion concentration has been determined to evaluate changing speciation in the ionic liquid. Cyclic voltammetry has been carried out to ascertain the reduction potential and diffusion coefficient of the reacting species. For pure ethaline the density was found to decrease by <5% with increase in temperature. On the other hand, the viscosity was found to decrease and conductivity was found to increase by 65% over the same temperature range. The inclusion of metal salts in ethaline had negligible effect on these parameters. Potential measurements showed that copper was reduced through a two-step mechanism and Sn was reduced via a two electron transfer route. The diffusion coefficient values for Cu ²⁺ and Sn²⁺ species were 1·22 × 10 ^-11 and 1·96 × 10^-11 m² s ^-1 respectively.