Effect of the electrolyte on the electrochemical behavior of C60 fullerene films in dimethylformamide + water mixtures

Electrochemical reactions of C60 films were investigated by electrochemical quartz crystal microbalance measurements in dimethylformamide + water mixtures containing various electrolytes. It was established that the behavior depends on the cations (K+, Na+, Li+), and the anions (Cl−, Br−, I−), as well. These differences were attributed to the variation of the hydration/solvation of the ions participating in the electrochemical reactions. Since both cation and anion movement, and also solvation and desolvation of the film were detected, each component of the solution had marked effect in the electrochemical activity. Depending on the experimental conditions, we could measure chemically reversible formation of alkali metal fullerides and also hydrogenated fullerides. It was suggested, that reversible hydrogenation of the whole film could occur via ion exchange, when the structure of the films were very loose, open to the movement of ions.