Study of an Al, Na, Li/Cl Three-Component System for Sodium–Nickel-Chloride Batteries

The electrical conductivity and thermochemical and electrochemical properties of a system consisting of melts of aluminum trichloride and sodium-lithium chlorides taken in different ratios have been studied. In this system, the electrochemical behavior of Ni²⁺ ions via cyclic voltammetry and the electromotive force in the modes of heating and cooling of the system were studied. It was found that the melting temperature of the melts passes through a minimum at a lithium chloride (хLiCl) content from 0.23 to 0.35. A possibility of reducing the starting temperature of a nickel-chloride battery with a partial replacement of sodium chloride with lithium chloride, as well as stabilization of its operation at a minimum temperature of 240°C, is shown. An admissibility of using the optimal compositions of the system as an electrolyte in sodium–nickel-chloride batteries has been established. It was found that the composition 0.5AlCl₃–0.23LiCl–0.27NaCl has a minimum melting point (111°C), a minimum activation energy for conductivity (8.9 kJ mol^–1), and a sufficiently high electrical conductivity (0.53 S cm^–1 at 250°C).