NOVELTY - A lithium battery (2) comprises anode (10), cathode, and heterogeneous electrolyte. The anode comprises lithium as active anode species. The cathode comprises active cathode species supported by cathode current collector. The heterogeneous electrolyte is between anode and cathode current collector. The electrolyte comprises two electrolyte solvents. The two electrolyte solvents are present disproportionately at the anode and cathode, respectively.    USE - A lithium battery used as rechargeable battery for electrochemical devices.    ADVANTAGE - The battery provides improved device performance and/or longer shorter device life. The battery provides high specific energy, e.g. greater than 400 Wh/kg, improved safety, and/or may be operable at - 70-75degrees C.    DETAILED DESCRIPTION - A lithium battery comprises anode, cathode, and heterogeneous electrolyte. The anode comprises lithium as active anode species. The cathode comprises active cathode species supported by cathode current collector. The heterogeneous electrolyte is between anode and cathode current collector. The electrolyte comprises two electrolyte solvents. The two electrolyte solvents are present disproportionately at the anode and cathode, respectively. The second electrolyte solvent includes at least one species that reacts with anode. The battery includes separator between anode and cathode. The separator contains second electrolyte solvent. The polymer gel layer is in contact with lithium or anode protective layer. The lithium battery includes separator (28). INDEPENDENT CLAIMS are included for:    (1) forming lithium battery; and    (2) operating lithium battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the battery that can allow partitioning of two liquid electrolyte solvents and includes separator and polymer layer associated with anode.    Lithium battery (2)    Anode (10)    Edge current collector (16)    Active anode material layer (18)    Protective layer (20)    Polymer gel layer (24)    Separator (28)