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wet-proof gas-supply layer, for example made of Teflon and acetylene black, a metal screen current collector and an active carbon layer. 

The type of metal used for the current collector may be chosen based on its chemical stability in the cell, specifically 5 its stability in contact with the aqueous catholyte. In specific embodiments the metal screen current collector may be composed of stainless steel, nickel copper, titanium or alloys thereof. 

One or more electrocatalysts may be used. In some embodiments a single electrocatalyst is used which is capable of facilitating both the oxygen evolution reaction (OER) on charge and the oxygen reduction reaction (OER) on discharge. In other embodiments two or more catalysts are incorporated in the cathode. A first electrocatalyst mate› rial for catalyzing the OER and stable down to, and prefer› ably beyond, the potential at which ORR takes place; and a second electrocatalyst for catalyzing the ORR and stable up to, and preferably beyond, the potential at which OER takes place. 

The active carbon layer may contain the electrocatalyst or may be uncatalyzed. One particularly suitable electrocata› lyst that may be used to catalyze one or both of the OER or ORR is iridium oxide compounds including compositionally pure iridium oxide and solid solution compounds thereof. 

Air cathodes suitable for use herein are described in detail elsewhere. In particular U.S. Pat. Nos. 7,645,543; 7,282, 295; and U.S Patent Publication No.: US 2009/0311596 all of which are hereby incorporated by reference in their entirety, and in particular for their description of air cathode structure and composition. 

Itemized Specific Embodiments 

The following is an itemization of some specific embodi› ments of the invention: 

1. An alkali metal/oxygen electrochemical energy storage 35 cell, the cell comprising: 

an anode comprising an alkali metal electroactive compo› nent material; 

a cathode on or at which molecular oxygen is electro› reduced during cell discharge, the 

cathode in alkali metal ion communication with the anode; 

a catholyte comprising water and one or more evaporative› loss resistant and/or polyprotic active compounds dis› solved in water that partake in a cell discharge reaction and effectuate cathode capacity for discharge in the acidic region, the catholyte in contact with said cathode; and 

a protective membrane architecture interposed between the cathode and the anode, the protective membrane archi› tecture having a first and second major surface, the first surface adjacent to the cathode and in contact with the catholyte and the second surface adjacent to the anode; 

and 

wherein the protective membrane architecture solely allows through transport of the alkali metal ion and prevents liquids from contacting the alkali metal anode. 

2. The cell of item 1, wherein the catholyte comprises: water; and 

a carboxylic acid dissolved in water, the acid represented by the following general formula 

<img src='content_image/945844.jpg'>

wherein R 1 represents an organic radical; 2 

wherein R represents H or an organic radical; and 3 

wherein R represents H or an organic radical. 

3. The cell of item 2, wherein at least one of the organic radicals represented by R 1 , R $^{2 }$or R$^{3 }$comprises a carboxyl group. 

4. The cell of item 3, wherein the carboxylic acid is malonic acid, thus R 2 and R 3 represent H and R 1 represents a carboxyl group. 2 3 

5. The cell of item 2, wherein at least one ofR1, R and R represents an organic radical selected from the group consisting of an optionally substituted C$_{1 }$-C$_{10 }$alkyl group, optionally substituted C$_{2}$-C$_{10 }$ alkenyl group, optionally substituted C$_{2}$-C$_{10 }$alkynyl group. 2 3 

6. The cell of item 2, wherein at least one ofR1, R and R represents an organic radical selected from the group consisting of an optionally substituted C$_{4}$ -C$_{10 }$cycloalkyl, optionally substituted C$_{4}$-C$_{10 }$ cycloalkenyl, and option› ally substituted 3-10 membered heterocyclyl. 2 3 

7. The cell of item 2, wherein at least one ofR1, R and R represent an organic radical selected from the group consisting of an optionally substituted carbo- and hetero› cyclic 5-10 membered aryl. 

8. The cell of item 2, wherein the carboxylic acid is selected from the group consisting of malonic acid, glutaric acid, and methylsuccinic acid. 

9. The cell of item 2, wherein the equivalent weight of the acid that partakes in the cell discharge reaction, is selected from the range of values consisting of 50-70 g/equivalent of H+; 71-90 g/equivalent of H+; 91-110 g/equivalent of H+. 

10. The cell of item 2, wherein the concentration of the carboxylic acid in the catholyte is greater than 1 molar. 

11. The cell of item 2, wherein the concentration of the carboxylic acid in the catholyte is 0.5 molar or greater. 

12. The cell of item 2, wherein the concentration of the carboxylic acid in the catholyte is 0.25 molar or greater. 

13. The cell of item 2, wherein the concentration of the carboxylic acid in the catholyte is between 0.05 molar and 1 molar. 

14. The cell of item 2, wherein the catholyte further com› prises solid phase carboxylic acid in contact with its solution. 

15. The cell of item 2, wherein the catholyte is saturated with the carboxylic acid. 

16. The cell of item 2, wherein the carboxylic acid is malonic acid. 

17. The cell of item 16, wherein the concentration of malonic acid in the catholyte is selected from the molar range consisting of 0.5 molar to 2 molar, 2 molar to 4 molar, and greater than 4 molar. 

18. The cell of item 2, further comprising a lithium salt dissolved in water. 

19. The cell of items 18, wherein the lithium salt is selected from the group consisting of lithium nitrate, lithium sulfate, and lithium perchlorate. 

20. The cell of item 18, wherein the lithium salt is lithium nitrate. 

21. The cell of item 18, wherein the concentration of the lithium salt in the catholyte is selected from the molar range consisting of 0.5 molar to 1 molar, 1 molar to 2 molar, and greater than 2 molar. 

22. The cell of item 20, wherein the carboxylic acid is malonic acid and the concentration of malonic acid in the catholyte is about 2 molar or about 4 molar or therebe› tween, and further wherein the concentration of the lithium nitrate salt is about 2 molar. 

