Zinc-air batteries offer high energy density and safety but are prone to chemical instability due to the use of alkaline electrolytes. A solution developed by an international research team relies on a nonalkaline electrolyte to realize a new battery chemistry that is more reversible and efficient.

Conventional alkaline electrolytes require a four-electron reduction of oxygen to water, which is a slow process. The basis of the innovative battery chemistry for the zinc-air battery is a non-alkaline, aqueous electrolyte. Source: WWU - MEET (Judith Kraft)The basis of the innovative battery chemistry for the zinc-air battery is a non-alkaline, aqueous electrolyte. Source: WWU - MEET (Judith Kraft)The new nonalkaline electrolyte based on a zinc trifluoromethanesulfonate anion supports battery operation with a two-electron zinc-oxygen/zinc peroxide chemistry that is far more reversible. By making the electrolyte hydrophobic, water is excluded from the near surface of the cathode, thus preventing the four-electron reduction and resulting in batteries featuring higher energy density and better cycling stability.

The fully rechargeable zinc-air batteries demonstrated stable long-term operation for 320 cycles and 1,600 hours under ambient air atmosphere.

The research conducted by scientists from University of Münster (Germany), Fudan University (China), Huazhong University of Science and Technology (China), University of Maryland, U.S. Army Research Laboratory and Helmholtz Institute Münster (Germany) is published in Science.

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