ELECTROCHEMISTRY OF METAL CHLORIDE CATHODES IN SODIUM BATTERIES

Transition metal dichlorides in sodium tetrachloroaluminate melts are viable alternatives to sulfur cathodes in sodium batteries in view of their potential advantages. Fundamental electrochemical studies on three candidate materials, i.e., FeCl2, NiCl2, and CuCl2, were carried out using various techniques such as cyclic voltammetry, linear polarization, potentiodynamic polarization, and ac impedance. These studies were aimed at identifying various rate processes in the reduction, elucidating the reaction mechanisms, and determining the kinetic parameters for the reduction. The limitations in the performance of these cathode materials in high power density applications were also examined. Finally, recommendations were made from these studies for the selection of a candidate system among these materials for future NASA applications. © 1990, The Electrochemical Society, Inc. All rights reserved.