The effects of Bi content (0–0.12 wt.%) on the self-corrosion properties, the open-circuit potential, the electrochemical impedance spectroscopy, the potentiodynamic polarization curves, and the battery performances of Al-0.4Mg-0.05Sn-0.015Ga alloys were investigated; meanwhile, the microstructures and the post-discharge surfaces of the alloy were also examined by SEM. The results show that Bi can increase the amount of the precipitated phase containing Bi. The Al-0.4Mg-0.05Sn-0.015Ga-0.10Bi alloy exhibits the optimum electrochemical properties; it has the greatest negative open circuit potential of −1.780 V, the highest constant current discharge voltage of 1.287 V, and a minimum self-corrosion rate of 0.132 mL cm⁻² min⁻¹; a uniform corrosive surface is obtained after discharge.