4. Zebra" rechargeable battery

Most of the difficulties encountered with the sodium-sulfur battery arose at the cathode. These are mainly due to the insulating nature of sulfur, its volatility and the high melting temperatures of sodium polysulfides. This led to various attempts to combine the liquid sodium-alumina β couple with a more practical positive active material. The implementation, around 210 ˚C, of a molten mixture of antimony trichloride SbCl ₃ and sodium tetrachloroaluminate NaAlCl ₄ was unsuccessful, but proved instructive. This work led to a new type of accumulator, consisting of a liquid sodium anode, a β-alumina primary electrolyte, the other side of which is wetted by a mixture of molten sodium tetrachloroaluminate and a transition metal chloride insoluble in molten NaAlCl ₄ ...