On some problems of the zinc-bromine system as an electric energy storage system of higher efficiency. I, Kinetics of the bromine electrode

Abstract The addition of bromine to different quarternary ammonium compounds which are important for working of the zinc/bromine battery and the interaction of the polybromides with the electrolyte and electrode material were investigated. Using cyclovoltammetry and the method of rotating disc electrode the kinetics of the bromine/polybromide electrode were studied in different aqueous salt solutions, differing from each other by their intensity of interaction with the bromine molecule. The bond strength of the bromine to the cation increases in the order NaBr, ZnBr 2 , NH 4 Br. The peak potential differences are enhanced with increasing interaction between bromine and cation, whereas exchange current densities decrease to the same extent. The rate constant of the heterogeneous charge transfer determined from rd -measurements also indicates an inhibition of the charge transfer in the anodic process when NH 4 Br is used.