The Electrochemical Behavior of Calcium Electrodes in a Few Organic Electrolytes

The electrochemical behavior of calcium electrodes in a few important organic electrolyte has been investigated. The solvents used included acetonitrile, tetrahydrofuran, γ-butyrolactone, and propylene carbonate, and the salts included. Ca(ClO₄)2, Ca(BF₄)₂, LiAsF₆, and tetrabutyl ammonium salts (ClO^-₄, BF^-₄). Various techniques, including cyclic voltammetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and x-ray microanalysis were used in order to characterize discharge processes of calcium anodes in the various systems, and to correlate them with the surface chemistry and morphology of calcium in the electrolyte solutions. Some important surface species formed in the above systems were identified. It was found that, as with lithium, discharge of calcium anodes is surface film-controlled. In contrast to lithium systems, however, calcium deposition in these solvent systems, either on calcium or noble metal electrodes, is impossible, due to the nature of the surface films formed.