Solubility of nickel chloride in molten sodium chloro aluminate

Sodium metal chloride batteries operating in the temperature range of 523 K are being investigated extensively as high energy secondary storage systems, They use of sodium anode and transition metal chloride in liquid sodium chloroaluminate as cathode and beta alumina as solid electrolyte. While a lot of research effort had gone into investigating sodium beta alumina anode in course of development of sodium sulphur batteries, the relatively new metal chloride cathode in sodium chloroaluminate have not been extensively investigated. In this work the solubility of nickel chloride in basic sodium chloroaluminate over a temperature range of 448 to 523 K was measured to ascertain the chemical reversibility of nickel chloride cathode material. Electrochemical investigations on nickel electrode was also carried out to establish the electrochemical reversibility of nickel chloride cathode, Half cell of configuration Ni/NaAlCl4/Al was assembled and both high speed voltammetric and high resolution chronopotentiometric investigations were carried out in the temperature range of 448 to 523 K, Well defined symmetric cyclic voltammograms were obtained in the scan rate of 10 mVs(-1) to 10 Vs(-1). The voltammetric and chloropotentiometric investigations establish that the redox behaviour is governed only by diffusion in the time frame of the experiment. Solubility of nickel chloride in basic sodium chloroaluminate melt was measured from voltammetric and chronopotentiometric investigations on a tungsten inert electrode using a cell of configuration W/NaAlCl4, NiCl2/Al. The mass transfer parameters derived from the cell Ni/NiAlCl4/Al were used for this measurement.