Patent ID: 8202649

Claim:
A battery cell, comprising: an active metal anode comprising an alkali metal or alkali metal alloy selected from the group consisting of binary and ternary alkali metal alloys with Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, and In, the anode having a first surface and a second surface; a cathode structure comprising a porous electronically conductive support component, an ionically conductive component, and an electrochemically active component, wherein at least one cathode structure component comprises an aqueous constituent; an ionically conductive protective membrane on the first surface of the anode, the membrane comprising, a first component in contact with the anode that is ionically conductive and chemically compatible with the active metal of the anode, the first component comprising a material selected from the group consisting of a composite reaction product of the active metal with a metal nitride, a composite reaction product of the active metal with a metal halide, a composite reaction product of the active metal with a metal phosphide, a reaction product of the active metal with red phosphorus, and a reaction product of the active metal with LiPON coated with a wetting layer, and a second component in contact with the first component, the second component being substantially impervious, ionically conductive and chemically compatible with the first component and the cathode structure; wherein the first component is an in situ reaction product of active metal of the active metal anode with a first component precursor formed by application of the active metal anode to the precursor disposed on the second component.