Electrochemical Behavior of Silver in 1-Ethyl-3-methylimidazolium Tetrafluoroborate Molten Salt

Abstract

A room-temperature molten salt, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4)(EMIBF4) with adequate purity was obtained simply by the reaction of 1-ethyl-3-methylimidazolium chloride and tetrafluoroboric acid. Silver tetrafluoroborate dissolves up to ∼0.2 mol dm⁻³ in EMIBF4EMIBF4 at room temperature. Electrochemical deposition and dissolution of silver on a platinum electrode were found possible in EMIBF4EMIBF4 containing AgBF4.AgBF4. The reduction of monovalent silver species is electrochemically irreversible, the rate constant being estimated to be 1×10−51×10−5 cm s⁻¹. The diffusion coefficient of Ag(I) is calculated to be 6×10−76×10−7 cm² s⁻¹, suggesting that Ag(I) exists as a substantially bare cation (Ag+)(Ag+) in EMIBF4.EMIBF4. © 2001 The Electrochemical Society. All rights reserved.