vii) 2 molar citric acid and 2 molar lithium nitrate; 

viii) 2 molar lithium dihydrogen citrate and 2 molar lithium nitrate; 

ix) 1 molar lithium dihydrogen citrate and 1 molar lithium nitrate; 

x) 2 molar imidazolium dihydrogen citrate and 2 or 1 molar lithium nitrate; 

xi) 2 molar imidazolium hydrogen citrate and 2 or 1 molar lithium nitrate; 

xii) 2.5 molar magnesium nitrate, 0.5 molar zinc nitrate and 1 molar lithium nitrate (pH about 3.1); 

xiii) 2.8 molar magnesium nitrate, 0.2 molar zinc nitrate, and 1 molar lithium nitrate (pH about 3.5); 

xiv) 2.95 molar magnesium nitrate and 0.05 molar zinc nitrate and 1 molar lithium nitrate (pH about 3.8). 

Other Cell Components 

With reference to FIG. lA, the cell comprises a Li anode 1. The anode may be an alkali metal, alloy or intercalation material, for example Li metal or a Li metal alloy or Li intercalation material (e.g., lithiated carbon). In one example, a Li metal foil may be used. Lithium anodes, including intercalation anodes and lithium alloys and lithium metal anodes are well known in the lithium battery art. In preferred embodiments the anode is lithium metal ( e.g., in foil or sintered form) and of sufficient thickness (i.e., capacity) to enable the cell to achieve the rated discharge capacity of the cell. The anode may take on any suitable form or construct including a green or sintered compact (such as a wafer or pellet), a sheet, film, or foil, and the anode may be porous or dense. Without limitation, the lithium anode may have a current collector ( e.g., copper foil, or suitable expandable metal) pressed or otherwise attached to it in order to enhance the passage of electrons between it and the leads of the cell. Without limitation the cell may be anode or cathode limited. When anode limited, the complete discharge (corresponding to rated capacity) will substan› tially exhaust all the lithium in the anode. When cathode limited, some active lithium will remain subsequent to the cell delivering its rated capacity. 

The anode is protected with a protective membrane archi› tecture chemically stable to both the anode and the envi› ronment of an adjacent cathode compartment (4). The pro› tective membrane architecture typically comprises a solid electrolyte protective membrane 2 and an interlayer 3. The solid electrolyte protective membrane is sometimes referred to herein as an ion membrane or a liquid impermeable alkali metal ion conductive solid electrolyte barrier layer. The protective membrane architecture is in ionic continuity with the Li anode 1 and is configured to selectively transport Li ions into and out of the cathode compartment 4 while providing an impervious barrier to the environment external to the anode. Protective membrane architectures suitable for use in the present invention are described in applicants’ co-pending published US Applications US 2004/0197641 and US 2005/0175894 and their corresponding International Patent Applications WO 2005/038953 and WO 2005/ 083829, respectively, incorporated by reference herein. 

With reference to FIG. 1B, there is illustrated (in cross› section (left) and perspective (right)) an embodiment of a lithium air battery cell 10 in accordance with the instant invention. The cell is disposed in a case 11 ( e.g., a metal or polymeric case, including but limited to a heat sealable multilayer laminate used for that purpose). The case com› prises one or more ports 12 for the passage of oxygen and moisture from the ambient air. To effectively reach the 

cathode and the cathode compartment, as illustrated in FIG. 1B, the case side wall of which contains the ports is adjacent to the cathode. 

In many, but not necessarily all embodiments, the cell is activated by removing a barrier material (not shown) which covers the ports to prevent, prior to cell activation, prema› ture or excessive exposure of the cathode compartment to ambient air. The cell activated by removing the barrier material ( e.g., by the act of peeling off a tab (barrier material layer). 

The case may further comprise an additional port (not shown) for introducing, water or catholyte into the cathode compartment after the cell has been manufactured. Without limitation, the catholyte ( or water) may be introduced, prior or subsequent to one or more of the following: cell activation or initial discharge. For instance, the cell may be used in a Li/ Air, or more specifically, a Li/O$_{2 }$ flow battery, wherein the catholyte is caused to flow into, and generally through, the cathode compartment. In accordance with such embodi- ments the battery may contain appropriate pipeworks and pumps for circulating the catholyte may be stored external from the cell in, e.g., a suitable storage container. 

FIGS. 2A-D illustrate representative protective mem› brane architectures from these disclosures suitable for use in the present invention. The protective membrane architec› tures provide a barrier to isolate a Li anode from ambient and/or the cathode side of the cell while allowing for efficient ion Li metal ion transport into and out of the anode. The architecture may take on several forms. Generally it comprises a solid electrolyte layer that is substantially impervious, ionically conductive and chemically compatible with the external ambient (e.g., air or water) or the cathode environment. 

Referring to FIG. 2A, the protective membrane architec› ture can be a monolithic solid electrolyte 202 that provides ionic transport and is chemically stable to both the alkali metal anode 201 and the external environment. Examples of such materials are Na-W’ alumina, LiHfPO$_{4 }$ and NASICON, Nasiglass, Li$_{5}$La$_{3 }$Ta$_{2}$O$_{12 }$ and Li$_{5}$La$_{3}$Nb$_{2}$O$_{12}$. Na$_{5}$MSi$_{4}$ O$_{12 }$ (M: rare earth such as Nd, Dy, Gd). 

More commonly, the ion membrane architecture is a composite composed of at least two components of different materials having different chemical compatibility require› ments, one chemically compatible with the anode, the other chemically compatible with the exterior; generally ambient air or water, and/or battery electrolytes/catholytes. By "chemical compatibility" ( or "chemically compatible") it is meant that the referenced material does not react to form a product that is deleterious to battery cell operation when contacted with one or more other referenced battery cell components or manufacturing, handling, storage or external environmental conditions. The properties of different ionic conductors are combined in a composite material that has the desired properties of high overall ionic conductivity and chemical stability towards the anode, the cathode and ambi› ent conditions encountered in battery manufacturing. The composite is capable of protecting an alkali metal anode from deleterious reaction with other battery components or ambient conditions while providing a high level of ionic conductivity to facilitate manufacture and/or enhance per› formance of a battery cell in which the composite is incor› porated. 

Referring to FIG. 2B, the protective membrane architec› ture can be a composite solid electrolyte 210 composed of discrete layers, whereby the first material layer 212 (also sometimes referred to herein as "interlayer") is stable to the alkali metal anode 201 and the second material layer 214 is 

