Long-duration cathode materials

A method of storing and discharging electrical energy in a metal-air battery, comprising:

• providing a layered cell including:
• a multi-function catalyst cathode including a metal hydroxide or oxide compound configured for redox reactions for a plurality of conjugate redox pairs;
• a multi-function catalyst cathode mentioned above mixed with MnO2 (or other commercial ORR catalysts) with a mass loading from zero to equivalent mass of a multi-function catalyst;
• a porous current collector configured for passage of at least one of the conjugate redox pairs;
• and
• an anode formed from anode materials of one or more of Fe, Fe(OH)2, FeOOH, Fe3O4, Zn, ZnO, Zn(OH)2;
• deep charging the layered cell for charging the anode materials to Fe(OH)2;
• charging the cathode to cathode to Ni/MOOH or (Ni/M)XOY, where M is a metal selected from the group consisting of Ni, Fe and Al, X is be 1 or 2 or 3, and Y can be 1or 2 or 3 or 4
• operating the cell in a nickel-iron battery mode by performing an Fe2+/Fe3+ redox in the anode and Ni2+/Ni3+ redox in the cathode;
• and
• operating the cell in an iron-air battery mode by performing an oxygen redox at the cathode.

A metal air battery, comprising:

• a nickel hydroxide or oxide compound defining a multifunction electrode layer configured for:
• i ) a nickel redox reaction,
• ii ) an oxygen evolution reaction (OER), and
• iii ) an oxygen reduction reaction (ORR);
• a cathode current collector layer adjacent the multifunction electrode layer, the cathode current collector formed from a porous nickel material;
• and
• a gaseous diffusion layer on an opposed side of the cathode current collector layer from the multifunction electrode layer, the gaseous diffusion layer configured for passage of O2;
• an overloaded anode layer, the overloaded anode layer including zinc or iron of a greater mass than the nickel compound in the multifunction electrode layer;
• a separator layer between the overloaded anode layer and the multifunction electrode layer, the separator layer configured for ionic conduction and fluidic retention;
• and
• an anode current collector on an opposed side of the overloaded anode layer from the separator layer.