MOLTEN TRIAZOLIUM CHLORIDE SYSTEMS AS NEW ALUMINUM BATTERY ELECTROLYTES

The possibility of using molten mixtures of 1,4-dimethyl-1,2,4-triazol ium chloride (DMTC) and aluminum chloride (AlCl3) as secondary battery electrolytes was studied, in some cases extended by the copresence of sodium chloride. DMTC-AlCl, mixtures demonstrated high specific condu ctivity in a wide temperature range. The equimolar system is most cond uctive and has kappa values between 4.02 x 10(-5) and 7.78 x 10(-2) S cm-1 in the range from -31 to 123-degrees-C, respectively. The electro chemical window of DMTC-containing sodium tetrachloroaluminate melts v aried in the region of 2.5 to 2.2 V (150-170-degrees-C) depending on m elt acidity and anode material. DMTC, being specifically adsorbed and reduced on the tungsten electrode surface, had an inhibiting effect on the aluminum reduction, but this effect was suppressed on the aluminu m substrate. An electrochemical process with high current density (ten s of milliamperes per square centimeter) was observed at 0.344 V on th e acidic sodium tetrachloroaluminate background, involving a free tria zolium radical mechanism. Molten DMTC-AlCl3 electrolytes are acceptabl e for battery performance and both the aluminum anode and the triazoli um electrolyte can be used as active materials in the acidic DMTC-AlCl 3 mixtures.