A Near-Neutral Chloride Electrolyte for Electrically Rechargeable Zinc-Air Batteries

Near-neutral electrolytes based on zinc chloride and ammonium chloride are examined for rechargeable zinc-air battery application. The effects of pH value, salt concentration, and polyethylene glycol and thiourea additives are investigated and a chloride electrolyte is developed. The reversible zinc deposition and zinc stripping processes are studied by cyclic voltammetry with rotating-disc electrode technique. The zinc anode and air cathode behaviors in near-neutral chloride electrolyte are characterized by quasi steady-state polarization and impedance spectroscopy. Prototyped zinc-air battery with near-neutral chloride electrolytes can sustain more than 1000 hours and hundreds of discharge-charge cycles with minimized zinc dendrite formation and no carbonate formation problem, under discharge-charge capacity ranging from 20 to 120 mAh. The near-neutral chloride electrolyte provides a safer and more robust alternative to traditional alkaline electrolyte for rechargeable zinc-air batteries.