NOVELTY - The alkali metal-cathode solution storage battery comprises an alkali metal anode (1) including an alkali metal and sodium metal, a cathode (5) comprising an electron conducting material and copper metal, an solid alkali ion conducting electrolyte separator separating an anode and the cathode, an anode side electrolyte (2) present between the anode and the separator, and a cathode side electrolyte (4) present between the cathode and the separator. The cathode side electrolyte has capacity to dissolve metal ions from the alkali metal and the electron conducting material.    USE - The alkali metal-cathode solution storage or rechargeable battery is useful: for grid energy storage applications such as load leveling; in power storage systems, electric vehicles, emergency power supplies, uninterruptible power supplies, peak shift apparatus for electric power systems and frequency-voltage stabilizers; and for storing wind and solar power on the electric grid.    ADVANTAGE - The economical alkali metal-cathode solution storage battery can be operated at low temperature with zero self discharge, and exhibits excellent energy density, high durability, safety and reliability, and good cell voltage and adequate pulse power.    DETAILED DESCRIPTION - The alkali metal-cathode solution storage battery comprises an alkali metal anode (1) including an alkali metal and sodium metal, a cathode (5) comprising an electron conducting material and copper metal, an solid alkali ion conducting electrolyte separator separating an anode and the cathode, an anode side electrolyte (2) present between the anode and the separator, and a cathode side electrolyte (4) present between the cathode and the separator. The cathode side electrolyte has capacity to dissolve metal ions from the alkali metal and the electron conducting material. An ion exchange reaction occurs during operation of the battery within the cathode side electrolyte. The anode side electrolyte is a non-aqueous liquid electrolyte comprising a salt of the alkali metal and an organic solvent. The cathode side electrolyte is a non-aqueous liquid electrolyte comprising an organic solvent. The battery has a planar arrangement, where the cathode and the anode are both substantially planar. The anode, the cathode, and the separator have same cross sectional area. The cathode includes 99 wt.% of the copper metal. The cathode further comprises a copper alloy including an alloying metal and 10-90 wt.% of the copper metal.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of alkali metal-cathode solution battery storage.    Alkali metal anode (1)    Anode side electrolyte (2)    Alkali ion conducting separator film (3)    Cathode side electrolyte (4)    Cathode. (5)