NOVELTY - A battery system (100) comprises: a metal oxygen battery (104) including a cathode (104a), and anode (104b) having a metal material; and an oxygen storage material (110) disposed within the metal oxygen battery. The oxygen storage material is in oxygen communication with the cathode.    USE - In a vehicle (claimed).    ADVANTAGE - The metal oxygen battery is free of water molecules. By using a relatively high concentration of oxygen at the positive electrode, and/or having increased oxygen diffusion rate at the positive electrode, the present metal-oxygen batteries have improved performance. Also the present battery reduces or eliminates requirements for many balance of plant components including positive electrode flow field, blower and air purification system, and susceptibility to contamination from atmospheric air impurities; increases battery system flexibility and reduces packaging costs; has simplified battery cell manufacturing procedures; and has improved battery performance kinetics via a reduction in bulk diffusion and an increase in surface diffusion.    DETAILED DESCRIPTION - A battery system (100) comprises: a metal oxygen battery (104) including a cathode (104a), and anode (104b) having a metal material; and an oxygen storage material (110) disposed within the metal oxygen battery. The oxygen storage material is in oxygen communication with the cathode. The battery system further comprises a control module controlling an oxygen flow between the oxygen storage material and the metal oxygen battery; and a separator (116) defining a first electrode compartment (112) including the cathode and a second electrode compartment (114) including the anode, where the oxygen storage material is disposed within the first electrode compartment. The metal oxygen battery is a closed system with regard to air transfer to and from atmospheric air. The oxygen storage material has an oxygen volumetric capacity of greater than 2 grams of oxygen per liter of the oxygen storage material. The metal oxygen battery includes the metal material and oxygen in has a first operating state. The metal oxygen battery includes an oxide or a peroxide of the metal material in a second operating state. The oxygen storage material has a first operating state of oxygen adsorption into the oxygen storage material; and a second operating state of oxygen desorption from the oxygen storage material. The battery system is used under a range of operating conditions including an operating pressure of 1-15 bar; and an operating temperature of 230-310 degrees K. The average diffusion distance from the oxygen storage material to the first electrode is 1 nm to 5 cm when the battery system is operating in an operating pressure of 1-100 bar and at an operating temperature of 230-310 degrees K. An INDEPENDENT CLAIM is included for operating a battery system involving inputting oxygen into a reversible closed-loop conduit from metal oxygen battery having an oxygen storage material internal to the metal oxygen battery; and outputting oxygen to the oxygen storage material from the reversible closed-loop conduit.    DESCRIPTION OF DRAWING(S) - The figure shows an illustrative view of a battery system for use in a vehicle.    Battery system (100)    Metal oxygen battery (104)    Cathode (104a)    Anode (104b)    Oxygen storage material (110)    First electrode compartment (112)    Second electrode compartment (114)    Separator (116)