NOVELTY - Producing an air electrode (14) for a metal-air battery (10), involves forming at least a portion of the air electrode using a process selected from an injection molding process and a screw extrusion process.    USE - For producing an air electrode for a metal-air battery (claimed); used in hearing aids, headsets (e.g. bluetooth or other wireless headsets), watches, medical devices, cameras, portable music players, laptops, phones (e.g. cellular phones), toys, portable tools; for providing energy storage and conversion solutions for peak shaving, load leveling, and backup power supply (e.g. for renewable energy sources such as wind, solar, and wave energy); for providing backup power e.g. for residential or commercial buildings such as homes or office buildings; used to provide motive power for an electric vehicle (e.g. hybrid-electric vehicle, plug-in hybrid electric vehicle, pure electric vehicle).    ADVANTAGE - The use of additional binding agents such as polyethylene (PE) and/or polypropylene (PP) in the air electrode allows for improved/new electrode formation methods, shapes, and applications for metal-air batteries. The incorporation of PE and/or PP (or other polymeric materials) into the material used to form the air electrodes provides improved mechanical strength without reducing conductivity or air diffusion rates. The polymeric materials such as PP and PE provides additional benefits for the air electrode, such as improving the resistance to chemical or mechanical degradation of the air electrode during operation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) metal-air battery comprising an air electrode formed according to the method, where the battery is a flow battery and the air electrode is part of a reaction tube for the flow battery;    (2) air electrode for a metal-air battery comprising a gas diffusion layer containing at least one material selected from polyethylene and polypropylene, and an active layer comprising polytetrafluoroethylene and not including polyethylene or polypropylene; and    (3) forming an air electrode, involving forming the gas diffusion layer using an injection molding process or a screw extrusion process.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of metal-air battery.    Metal-air battery (10)    Air electrode (14)    Oxygen distribution layer (16)    Electrolyte (18)    Separator (20)    Gas diffusion layer (30)    Active layer (22) Housing (32)