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A rechargeable molten salt electrolyte battery has an anode comprising lithium, a cathode electrode comprising a conductive metal that is compatible with the nitrate melt, an electrolyte comprising lithium nitrate or lithium nitrate mixtures with other nitrates which electrolyte is capable of becomi

A rechargeable molten salt electrolyte battery has an anode comprising lithium, a cathode electrode comprising a conductive metal that is compatible with the nitrate melt, an electrolyte comprising lithium nitrate or lithium nitrate mixtures with other nitrates which electrolyte is capable of becoming an ionic conductive liquid upon being heated above its melting point, wherein oxygen for reaction at the cathode or within the melt is provided from an external source to be delivered to the cathode through the electrolyte and provision is made to collect lithium oxide formed during discharge to be reconstituted as lithium ions and oxygen during recharge. At least a portion of the oxygen reduction reaction is provided by a nitrate ion pathway.

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1. A rechargeable molten nitrate salt electrolyte battery, comprising: a) an electrolyte comprising lithium nitrate which electrolyte is capable upon being heated above its melting point of becoming an ionically conductive liquid containing lithium ions and nitrate ions, the lithium nitrate being pr

1. A rechargeable molten nitrate salt electrolyte battery, comprising: a) an electrolyte comprising lithium nitrate which electrolyte is capable upon being heated above its melting point of becoming an ionically conductive liquid containing lithium ions and nitrate ions, the lithium nitrate being present at a level sufficient to provide stability for a protective solid electrolyte interface formed on lithium metal on contact with the electrolyte,b) an anode comprising lithium immersed in the electrolyte, the anode and the electrolyte being compatible with each other for introducing lithium ions into the electrolyte and having a stable layer of lithium oxide serving as the solid electrolyte interface formed on the surface of the lithium in contact with the electrolyte,c) a cathode electrode immersed in the electrolyte comprising an electrically conductive surface that is compatible with the electrolyte and capable of transferring electrical charge to or from chemical compounds, namely nitrate ions and oxygen, present within the electrolyte,d) oxygen atoms present within the electrolyte in the form of nitrate ions to serve as an internal source of oxygen within the electrolyte for providing oxygen atoms to be delivered, when the electrolyte is at a temperature above its melting point, through the electrolyte to the cathode electrode for reaction at the cathode whereby during battery discharge one or more lithium oxides are formed,e) electrical connections respectively present on the anode and cathode and electrically connected to the lithium in the anode and the electrically conductive surface of the cathode electrode for connecting the battery to an external circuit which will allow current to flow through the battery in conjunction with electrochemical reactions occurring at the anode and cathode electrode,f) a diffuser of external oxygen positioned within the electrolyte to introduce into the electrolyte oxygen gas from an external oxygen source to provide the direct reduction of the oxygen at the cathode as well as the reduction of the oxygen by a homogeneous chemical reaction with nitrite ions present in the electrolyte to form nitrate ions, andg) surfaces within the cell electrolyte for collecting lithium oxide formed during battery discharge, said surfaces being electrically connected to the cathode electrode for the lithium oxide to be dissociated into lithium ions and oxygen during battery recharging,wherein, when operated as a battery, the anode and cathode reactions are reversible in accordance with the polarity of the current flowing through the battery thereby providing a molten salt electrolyte battery which is rechargeable. 2. The battery of claim 1, comprising nitrite ions formed during battery discharge, in combination with oxygen introduced into the electrolyte from the external oxygen source for effecting a homogeneous chemical reaction with the nitrite ions to form nitrate ions and thereby replenish oxygen atoms depleted from the internal source of oxygen. 3. The battery of claim 2, wherein the electrolyte comprises oxygen in solution which constitutes a portion of the internal source of oxygen. 4. The battery of claim 3, wherein the electrolyte comprises as well as said lithium nitrate salt one or more additional salts compatible with battery operation which form a mixture with a melting temperature below that of pure lithium nitrate. 5. The battery of claim 4, wherein the electrolyte comprises a mixture of lithium nitrate and potassium nitrate with a melting temperature below that of pure lithium nitrate. 6. The battery of claim 4, wherein the electrolyte consists of lithium nitrate or a mixture of lithium nitrate and another nitrate salt excluding sodium nitrate which form a mixture with a melting temperature below that of pure lithium nitrate. 7. The battery of claim 1, wherein the cathode electrode surface comprises a conductive metal selected from the group consisting of nickel, iron, cobalt, copper, silver, chromium, platinum, and ruthenium or combinations thereof. 8. The battery of claim 7, wherein the anode comprises a lithium-aluminum alloy. 9. The battery of claim 7, wherein the anode comprises a material selected from the group consisting of a lithium-silicon alloy, a lithium-calcium alloy, a lithium-magnesium alloy, a lithium-boron alloy. 10. The battery of claim 7, wherein the anode comprises lithium which is immobilized with a metal selected from the group consisting of nickel, cobalt, and iron. 11. The battery of claim 1, wherein the surfaces within the cell electrolyte for collecting lithium oxide comprise a horizontal surface portion at the base of the cathode upon which oxides formed during discharge will be collected to facilitate the recharge cycle by positioning such oxides in close proximity to the cathode during the recharge cycle. 12. The battery of claim 1, comprising calcium or magnesium ions in the electrolyte in an amount sufficient to provide calcium or magnesium oxide as a portion of the stable layer of lithium oxide formed on the lithium anode. 13. The battery of claim 12, wherein the electrolyte of the battery is substantially free of sodium ions. 14. The battery of claim 13, wherein the electrolyte of the battery is substantially free of chloride ions. 15. The battery of claim 14, wherein the electrolyte of the battery is substantially free of water. 16. A method of using the molten salt electrolyte battery of claim 1, wherein the electrical connections of the battery of claim 1 are connected to each other through an external circuit to permit a battery discharge current to flow through the battery while providing oxygen to oxygen diffuser from the external oxygen source. 17. A method of using the molten salt electrolyte battery of claim 1 wherein the electrical connections of the battery of claim 1 are connected to each other through an external circuit which includes an electromotive source which causes current to flow through the battery to effect battery recharging by dissociation of lithium oxide present on the lithium oxide collection surfaces. 18. A method of operating a rechargeable molten salt electrolyte battery, the battery having: a) an electrolyte comprising lithium nitrate which electrolyte is capable of becoming an ionically conductive liquid upon being heated above its melting point,b) an anode comprising lithium that is compatible with the electrolyte for introducing lithium ions into the electrolyte, andc) a cathode electrode comprising an electrically conductive surface material that is compatible with the electrolyte,comprising the step of providing during battery discharge oxygen to the electrolyte for reaction at the cathode to form lithium oxides by introducing external oxygen into the battery through the electrolyte. 19. The method of claim 18, wherein the oxygen which is provided to the electrolyte reacts homogeneously with nitrite ions present therein to form nitrate ions which provide at least a portion of the oxygen within the electrolyte for reaction at the cathode.