An Aluminum Acid‐Base Concentration Cell Using Room Temperature Chloroaluminate Ionic Liquids

Mixtures of 1‐methyl‐3‐ethylimidazolium chloride (MEICl) and aluminum chloride are molten salts at room temperature and below. Acidic melts, which contain mole fraction greater than 0.5, can be used as catholytes, with basic melts as anolytes, in a concentration cell using Al plate electrodes and a microporous polypropylene separator. Gravimetric analysis of electrodes indicates that the anode reaction is and the cathode reaction is The open‐circuit potential for the cell is 1.38V, and the voltage remains above 1.0V at constant current discharge of 1–3 mA for 6 cm 2 Al electrodes. Coulometry is combined with gravimetric and compositional analysis (using NMR spectroscopy) of the electrolytes to estimate transport numbers.