An alkali/oxidant battery is provided with an associated method of creating battery capacity. The battery is made from an anode including a reduced first alkali metal such as lithium (Li), sodium (Na), and potassium (K), when the battery is charged. The battery's catholyte includes an element, in the battery charged state, such as nickel oxyhydroxide (NiOOH), manganese(IV) (oxide Mn(4+)O2), or iron(III) oxyhydroxide Fe(3+)(OH)3), with the alkali metal hydroxide. An alkali metal ion permeable separator is interposed between the anolyte and the catholyte. For example, if the catholyte includes nickel(II) hydroxide (Ni(OH)2) in a battery discharged state, then it includes NiOOH in a battery charged state. To continue the example, the anolyte may include dissolved lithium ions (Li+) in a discharged state, with solid phase reduced Li formed on the anode in the battery charged state.