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Air-breathing throwaway batteries could be a cheap answer for those
situations where your cellphone needs charging and there isn’t a power supply in
sight, according to Electric Fuel of Israel. The company has applied for world
patents on its zinc-air throwaway (WO 00/36690). Oxygen from the air reacts with
water to form hydroxyl ions, which migrate to a zinc anode where they react with
the metal. This releases electrons and generates a current. Each battery
contains a number of small cells inside a case peppered with holes. Heat from
the cells creates a draught that keeps the cells supplied with fresh air.