Abstract: Batteries and especially secondary batteries employing an anode comprising aluminum and a molten, non-aqueous electrolyte containing admixtures of aluminum halide and 1,2,3-trialkylimidazolium halides having the formula TimX: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are independently alkyl groups of 1 to 12 carbons and X is independently halide or mixtures of halides, e.g., chloride and/or bromide are disclosed. The molar ratio of aluminum hereinafter denoted by Al, to trialkylimidalozium, hereinafter denoted by Tim, in the electrolyte, may be varied over a wide range so as to make the molten electrolyte composition acidic and as such the electrolyte is useful in batteries, especially secondary batteries employing aluminum anodes and a variety of cathodes.