Anodic dissolution of aluminium in organic electrolytes containing perfluoroalkylsulfonyl imides

Electrochemical dissolution of aluminium has been investigated in various solutions composed of organic solvents and 1 M lithium bis(perfluoroalkylsulfonyl) imide salts. Potentials of the onset of transpassive dissolution and repassivation as well as dissolution currents have been measured for several systems by using voltammetric methods. Empirical correlation between the composition of the solvent and the dissolution current has been established for mixtures of ethylene carbonate and ethylmethyl carbonate. The effect of the perfluoroalkyl chain length on the dissolution rate has also been studied and the result has been elucidated with the help of considerations on the structure of the ions. Mechanistic information obtained from electrochemical impedance spectra revealed that at least two adsorbed intermediates have to be included in the dissolution mechanism. Conditions of application of lithium perfluoroalkylsulfonyl imides in lithium ion batteries are briefly discussed.