Metal-air cell with minimal air access

Abstract

The battery includes an air cathode, an anode, an aqueous electrolyte, and a housing, the housing including one or more air access ports defining a total air vent area, the battery exhibiting a current density, the ratio of the current density to the total air vent area being about 100 mA / mm 2 and the aqueous electrolyte comprises an amphoteric fluorosurfactant.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 365,328, filed July 1, 2021, the contents of which are incorporated herein by reference.

[0002] The present technology relates generally to the field of metal-air batteries and their uses. Summary of the Invention

[0003] In one aspect, a battery is provided that includes an air cathode, an anode, an aqueous electrolyte, and a housing, the housing having one or more air access ports that define a total air vent area, the battery exhibiting a cell limit current at 1.15 V, the ratio of the cell limit current at 1.15 V to the total air vent area being about 100 mA / mm 2 and the aqueous electrolyte comprises an amphoteric fluorosurfactant. In some embodiments, the ratio is about 150 mA / mm 2 In some embodiments, the ratio is greater than 250 mA / mm 2 In some embodiments, the ratio is greater than about 70 mA / mm 2 ~Approx. 1000mA / mm 2 In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 5.4 mm. In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 3.6 mm. In some embodiments, the battery has a nominal external volume of about 180 mm. 3 ~about 270mm 3 In some embodiments, the battery has a nominal electrode interface area of ​​about 35 mm 2 In some embodiments, the battery is about 25-50 mm 2 In some embodiments, the total vent area is about 0.030 mm 2 ~about 0.115mm 2 In some embodiments, the cell current limit at 1.15 V is between about 4 mA and about 15 mA.

[0004] In another aspect, a battery is provided comprising an air cathode, an anode, an aqueous electrolyte, and a housing, the housing comprising one or more air access ports defining a total air vent area, the battery having an interfacial surface area between the anode and the cathode, the ratio of the air vent area to the interfacial area being about 3×10 -3 (However, if the battery is a size 13 battery, the ratio is approximately 2.4×10 -3 or less), and the aqueous electrolyte comprises an amphoteric fluorosurfactant. In some embodiments, the ratio is about 1.0×10 -3 ~Approx. 3.0×10 -3 In some embodiments, the ratio is about 1.0×10 -3 ~Approx. 2.4×10 -3 In some embodiments, the ratio is about 1.4×10 -3 ~Approx. 3.0×10 -3 In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 5.4 mm. In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 3.6 mm. In some embodiments, the battery has a nominal external volume of about 180 mm. 3 ~about 270mm 3 In some embodiments, the battery has a nominal electrode interface area of ​​about 25 to 50 mm 2 In some embodiments, the total vent area is about 0.030 mm 2 ~about 0.115mm 2 It is.

[0005] In a further aspect, a battery is provided comprising an air cathode, an anode, an aqueous electrolyte, and a housing, the housing comprising one or more air access ports defining a total air vent area, the battery exhibiting a cell limit current at 0.9 V and a cell limit current at 1.15 V, a ratio of the cell limit current at 1.15 V to the cell limit current at 0.9 V is greater than about 0.6, and the aqueous electrolyte comprises an amphoteric fluorosurfactant. In some embodiments, the ratio is greater than about 0.7. In some embodiments, the ratio is greater than 0.75. In some embodiments, the ratio is between about 0.6 and 0.9. In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 5.4 mm. In some embodiments, the battery has a nominal diameter of about 8 mm and a nominal height of about 3.6 mm. In some embodiments, the battery has a nominal external volume of about 180 mm. 3 ~about 270mm 3 In some embodiments, the nominal electrode interface area is about 35 mm 2 In some embodiments, the total vent area is about 0.030 mm 2 ~about 0.13mm 2 In some embodiments, the cell current limit at 1.15 V is between about 4 mA and about 15 mA.

[0006] In yet another aspect, a battery is provided comprising an air cathode, an anode, an aqueous electrolyte, and a housing, the housing comprising one or more air access ports defining a total air vent area, the battery exhibits a cell limit current at 0.9 V, the battery maintains a voltage of 1.17 V or greater through 50% of its discharge to 0.9 V when discharged at a current equal to half the limit current, and the aqueous electrolyte comprises an amphoteric fluorosurfactant.

[0007] In a further aspect, a battery is provided comprising an air cathode, an anode, an aqueous electrolyte, and a housing, the housing comprising one or more air access ports defining a total air vent area, the battery exhibits a cell limit current at 0.9 V, the battery maintains a voltage of 1.20 V or greater through 50% of its discharge to 0.9 V when discharged at a current equal to one-third of the limit current, and the aqueous electrolyte comprises an amphoteric fluorosurfactant. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional schematic diagram illustrating an exemplary electrochemical cell. [Diagram 2] FIG. 13 is a box plot of capacity data for an embodiment of a size 13 cell of the present technology against a comparative "standard" cell discharged at 10 / 2 mA at 80% RH (relative humidity) according to ANSI / IEC testing, according to an example. [Diagram 3] FIG. 13 is a box plot of capacity data for an embodiment of a size 312 cell of the present technology against a comparative "standard" cell discharged at 10 / 2 mA at 80% RH (relative humidity) according to ANSI / IEC testing, according to an example. [Figure 4] FIG. 13 is a box plot of capacity data for an embodiment of a size 312 cell of the present technology against a comparative "standard" cell discharged at 10 / 2 mA at 20% RH (relative humidity) according to ANSI / IEC testing, according to an example. [Diagram 5] 1 is an example plot of potential versus a pure zinc reference when current draws of 1 mA / cm2 and 5 mA / cm2 are applied to the cathode of a metal-air cell using three different electrolytes. [Figure 6] 1 is a plot of the ratio of cell limit current at 1.15V to cell limit current at 0.9V for a cell according to the present application (left) versus a commercial cell (right), according to an embodiment. [Figure 7] 1 is a scatter plot of limiting current at 1.15 V versus limiting current at 0.9 V for cells according to the present application (solid circles) and commercial cells (open diamonds), according to an embodiment. [Figure 8]1 is a set of constant current discharge curves for two size 13 cells according to the present application and one commercial reference cell, showing closed circuit voltage (V) vs. capacity (mAh) during discharge. See Example 8. [Figure 9] 1 is a set of constant current discharge curves for two size 13 cells according to the present application and one commercial reference cell, showing closed circuit voltage (V) vs. capacity (mAh) during discharge. See Example 8. [Figure 10] FIG. 13 is a box plot of capacity data for an embodiment of size 312 cells of the present technology with three different total venting areas ranging from 0.0330 mm to 0.0869 mm, discharged at 10 / 2 mA at 50% RH (relative humidity) according to ANSI / IEC testing, according to an example. [Figure 11] FIG. 13 is a box plot of capacity data for an embodiment of size 312 cells of the present technology with three different total vent areas ranging from 0.0330 mm to 0.0869 mm, discharged at 5 / 2 mA at 50% RH (relative humidity) according to ANSI / IEC testing, according to an example. [Figure 12] FIG. 13 is a box plot of capacity data for an embodiment of size 13 cells of the present technology with three different total vent areas ranging from 0.0499 mm to 0.1295 mm, discharged at 12 / 3 mA at 50% RH (relative humidity) according to ANSI / IEC testing, according to an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Various embodiments are described below. It should be noted that the specific embodiments are not intended as exhaustive descriptions or as limitations to the broader aspects discussed herein. An aspect described in conjunction with a specific embodiment is not necessarily limited to that embodiment and can be practiced with any other embodiment.

[0010] As used herein, "about" is understood by those of ordinary skill in the art and will vary to some extent depending on the context in which it is used. If there are uses of a term that are not clear to those of ordinary skill in the art, given the context in which it is used, "about" will be understood to mean up to plus or minus 10% of the particular term, for example, "about 10% by weight" will mean "9% to 11% by weight". When "about" precedes a term, the term should be interpreted as disclosing the term with "about" as well as the term not modified by "about", for example, "about 10% by weight" should be understood to disclose "9% to 11% by weight" as well as "10% by weight".

[0011] The use of the terms "a," "an," and "the" and similar referents in the context of describing elements (particularly in the context of the claims that follow) should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually referred to herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "to etc.") provided herein is intended merely to better illustrate the embodiments and does not present limitations on the scope of the claims, unless otherwise indicated. No language in this specification should be construed as indicating non-claimed elements as essential.

[0012] Generally, "substituted" refers to an alkyl, alkenyl, alkynyl, aryl, or ether group (e.g., an alkyl group), as defined below (e.g., an alkyl group), in which one or more bonds to a hydrogen atom contained therein are replaced by a bond to a non-hydrogen atom or a non-carbon atom. Substituted also includes groups in which one or more bonds to a carbon or hydrogen atom are replaced by one or more bonds, including double or triple bonds, to a heteroatom. Thus, unless otherwise specified, a substituted group is substituted with one or more substituents. In some embodiments, a substituted group is substituted with 1, 2, 3, 4, 5, or 6 substituents. Examples of substituents include halogens (i.e., F, Cl, Br, and I), hydroxyl, alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy groups, carbonyl (oxo), carboxyl, esters, urethanes, oximes, hydroxylamines, alkoxyamines, aralkoxyamines, thiols, sulfides, sulfoxides, sulfones, sulfonyls, sulfonamides, amines, N-oxides, hydrazines, hydrazides, hydrazones, azides, amides, ureas, amidines, guanidines, enamines, imides, isocyanates, isothiocyanates, cyanates, thiocyanates, imines, nitro groups, nitriles (i.e., CN), and the like.

[0013] As used herein, "alkyl" groups include straight-chain and branched-chain alkyl groups having 1 to about 20 carbon atoms, typically 1 to 12 carbons, or in some embodiments, 1 to 8 carbon atoms. The alkyl groups can be substituted or unsubstituted. Examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branched-chain alkyl groups include, but are not limited to, isopropyl, sec-butyl, t-butyl, neopentyl, and isopentyl groups. Representative substituted alkyl groups may be substituted one or more times, for example, with amino, thio, hydroxy, cyano, alkoxy, and / or halo groups, such as F, Cl, Br, and I groups. As used herein, the term haloalkyl is an alkyl group having one or more halo groups. In some embodiments, haloalkyl refers to a perhaloalkyl group.

[0014] Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. In some embodiments, cycloalkyl groups have 3 to 8 ring members, while in other embodiments, the number of ring carbon atoms ranges from 3 to 5, 6, or 7. Cycloalkyl groups can be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl, as well as fused rings such as, but not limited to, decalinyl. Cycloalkyl groups also include rings substituted with straight or branched chain alkyl groups, as defined above. Representative substituted cycloalkyl groups may be mono- or more than twice substituted, such as, but not limited to, 2,2-, 2,3-, 2,4-, 2,5-, or 2,6-disubstituted cyclohexyl groups, or mono-, di-, or tri-substituted norbornyl or cycloheptyl groups, which may be substituted, for example, with alkyl, alkoxy, amino, thio, hydroxy, cyano, and / or halo groups.

[0015] Alkenyl groups are straight, branched, or cyclic alkyl groups having 2 to about 20 carbon atoms and further containing at least one double bond. In some embodiments, alkenyl groups have 1 to 12 carbons, or typically 1 to 8 carbon atoms. Alkenyl groups can be substituted or unsubstituted. Alkenyl groups include, for example, vinyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienyl groups, among others. Alkenyl groups, like alkyl groups, can be substituted. Divalent alkenyl groups, i.e., alkenyl groups having two points of attachment, include, but are not limited to, CH-CH=CH2, C=CH2, or C=CHCH3.

[0016] The term "alkoxy" refers to a hydroxy group (OH) where the H is replaced by an alkyl group containing 1 to 12 carbon atoms, as defined herein. In some embodiments, the alkoxy group has 1 to 7 or 1 to 4 carbon atoms. The alkoxy group can be, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a n-butoxy group, a sec-butoxy group, a tert-butoxy group, a pentoxy group, a isopentoxy group, a 3-methylbutoxy group, a 2,2-dimethylpropoxy group, a n-hexoxy group, a 2-methylpentoxy group, a 2,2-dimethylbutoxy group, a 2,3-dimethylbutoxy group, a n-heptoxy group, a 2-methylhexoxy group, a 2,2-dimethylpentoxy group, a 2,3-dimethylpentoxy group, a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a 1-methylcyclopropyloxy group, and the like. In some embodiments, the alkoxy group comprises an O-C1-C6-alkyl group. In other embodiments, the alkoxy group comprises an O-C1-C4-alkyl group.

[0017] As used herein, the term "amine" (or "amino") refers to -NR 100 R 101 R 100 and R 101 are independently hydrogen or a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, aralkyl, heterocyclylalkyl or heterocyclyl group as defined herein. In some embodiments, the amine is an alkylamino, dialkylamino, arylamino, or alkylarylamino. In other embodiments, the amine is NH2, methylamino, dimethylamino, ethylamino, diethylamino, propylamino, isopropylamino, phenylamino, or benzylamino.

[0018] As used herein, the term "halogen" or "halo" refers to bromine, chlorine, fluorine, or iodine. In some embodiments, the halogen is fluorine. In other embodiments, the halogen is chlorine or fluorine.

[0019] As used herein, the term "hydroxyl" may refer to -OH or its ionized form, -O-.

[0020] As used herein, the term "nitrile" or "cyano" refers to a --CN group.

[0021] As used herein, the term "thio" refers to an --S- group or an ether where the oxygen has been replaced with a sulfur.

[0022] As used herein, the term "amphoteric fluorosurfactant" refers to a fluorosurfactant that contains at least one cationic group and / or a group that can be protonated to a cationic group, such as a primary, secondary, tertiary, and / or quaternary amine group, and at least one anionic group and / or a group that can be deprotonated to an anionic group, such as a carboxy group, sulfonic acid group, phosphate group, phosphonic acid group, any one or more salts thereof.

[0023] As used herein, the term "betaine-functional" refers to a neutral compound having a positively charged cationic functional group and a negatively charged functional group. In some embodiments, the cationic functional group can be a quaternary ammonium or phosphonium cation that has no hydrogen atoms. In some embodiments, the negatively charged functional group can be a carboxylate group.

[0024] As used herein, the term "short chain perfluoro substituent" refers to a C1-C7 perfluoro substituent.

[0025] As used herein, the term "zinc anode" refers to an anode that includes zinc as the anode active material.

[0026] As used herein, unless expressly indicated otherwise, the term "ppm" means parts per million by weight.

[0027] As used herein, for amphoteric fluorosurfactants, the term "ppm" means parts per million by weight of active ingredient, unless expressly indicated otherwise.

[0028] In the design of metal-air cells, it is useful to define the characteristics of the cell in terms of limiting current. Cell limit current testing is performed by holding the cell at a particular voltage for a particular time and measuring the resulting current provided by the cell at a set time end point. When the cell is initially held at a voltage (using an instrument that adjusts the current drain from the cell to reach a set voltage), the current will be initially high and will asymptotically decline to a relatively constant level. Typically, the set time is selected at a point where the current lies within such a relatively constant range.

[0029] As used herein, "cell limiting current at 0.9 V" means the current provided by a metal-air electrochemical cell at 0.9 V at the end of 60 seconds that the cell was held at a voltage of 0.9 V. Prior to this test, the cell should not be subjected to any load for at least 60 seconds.

[0030] As used herein, "cell limiting current at 1.15 V" means the current provided by a metal-air electrochemical cell at 1.15 V at the end of 60 seconds that the cell was held at a voltage of 1.15 V. Prior to this test, the cell should not be subjected to any load for at least 60 seconds.

[0031] Here, it has been observed that oxygen utilization in metal-air electrochemical cells can be unexpectedly improved by the combination of an electrolyte with a fluorinated amphoteric surfactant and lithium hydroxide in a cell housing with limited air access. The electrolyte formulation has been found to allow for a reduction in the oxygen access required by the cell for a given current draw and / or increase the closed cell voltage and the cathode half-cell voltage while maintaining a desirable closed circuit voltage. Such higher efficiency in oxygen utilization and higher cell voltage allows for the use of a smaller vent area to the exterior of the cell, reducing exposure to the deleterious effects of moisture (H2O vapor) and carbon dioxide (CO2). Such higher efficiency in oxygen utilization and higher cell voltage also allows for the use of a less porous diffusion layer between the air access port and the active cathode material, also reducing exposure to the deleterious effects of moisture and CO2. These changes reduce oxygen access and enhance performance in low and high humidity conditions, as well as environments with high CO2 concentrations.

[0032] Described herein is a combination of a high voltage anode formulation made of an amphoteric fluorosurfactant and a cell designed to reduce the cell limit current to the lowest possible level while still meeting drain rate usage requirements.The technology provides a battery that includes an air cathode, an anode, an aqueous electrolyte that includes an amphoteric surfactant, and a housing that includes one or more air access ports that define the total area of ​​the void ("air vent area").The ratio of several variables to the air vent area has been tested for various cells.

[0033] In accordance with the surprising observations described herein, it has been discovered that when amphoteric fluorosurfactants are used in the electrolyte of the batteries of the present technology, the minimum required total vent area defined by the air access ports is surprisingly low. By way of example, in the improved batteries of the present technology, the total vent area of ​​a size 312 cell is 0.0660 mm 2 (Standard / conventional dimensions 0.0869mm 2In some embodiments, the vent area of ​​size 312 is 0.033 mm 2 In some embodiments, the vent area of ​​size 312 can be about 0.01 mm 2 ~about 0.1mm 2 , or about 0.03 mm 2 ~ approx. 0.07mm 2 As an example, in the improved battery of the present technology, the total air flow area of ​​a size 13 cell can be 0.0998 mm 2 (Standard / conventional dimensions 0.1295mm 2 In some embodiments, the vent area of ​​size 13 is 0.1295 mm 2 , or about 0.0499 mm 2 In some embodiments, the vent area of ​​size 13 is about 0.04 mm 2 ~about 0.15mm 2 , or about 0.05 mm 2 ~about 0.13mm 2 , or about 0.09 mm 2 ~about 0.13mm 2 Without being bound by theory, it is proposed that the reduced vent area is enabled by a high voltage and more efficient electrolyte formulation (i.e., including an amphoteric fluorosurfactant and, optionally, LiOH·xH2O), the amphoteric fluorosurfactant may help reduce voltage suppression while maintaining gassing reliability, and the combination of components in the anode may result in significant improvements in cell voltage and cell performance.

[0034] As a point of reference, a size 13 cell has external dimensions of approximately 8.0 mm in diameter and 5.4 mm in height, while a size 312 cell has external dimensions of approximately 8.0 mm in diameter and 3.6 mm in height. These are nominal dimensions, with typical actual dimensions being 0-0.2 mm smaller than the nominal dimensions. External volumes are calculated here as if the cell were a cylinder of nominal dimensions and are shown in Table 1 below, although actual cell volumes may be slightly smaller due to both deviations in the actual dimensions of each manufactured cell and the incorporation of a notch at one end of the cell to prevent reverse insertion of such small devices. Electrode interface area is calculated based on the diameter of the hole through the cell's inner insulator (6.7 mm). [Table 1] [Table 2]

[0035] As mentioned above, the dimensions provided are approximate and may range from their respective nominal values ​​to their respective actual values. Therefore, the external volume that can be calculated is approximately 150 mm for the cell. 3 ~about 300mm 3 Note that the interfacial area of ​​some cells may range from about 25 mm to about 30 mm. Additionally, the interfacial area of ​​some cells may vary for a number of reasons, including variations in the exact thickness of the cell housing, the actual diameter of the cell insulator, etc. Thus, the interfacial area may be in the range of about 25 mm. 2 ~ approx. 50mm 2 More broadly, the interface area of ​​similar format cells can range from 15 to 75 mm 2 The range is.

[0036] The cell limiting current of a cell at 1.15V is determined by the cell design. Design factors that affect this factor include, but are not limited to, the cell's air vent area, the porosity of the diffusion layer between the air access port and the cathode active layer, and the electrolyte and anode elements. Ultimately, these design factors affect the cell's ability to efficiently access and utilize oxygen. Thus, the ratio of limiting current at 1.15V to air vent area provides a measure of their capabilities, regardless of the size of the cells. According to various embodiments, a cell with a limiting current to air vent area ratio of 100 mA / mm2 at 1.15V is suitable for use with a cell with a 100 mA / mm2 limiting current. 2 In some embodiments, the ratio is about 150 mA / mm 2 May be greater than 200mA / mm 2 It may be greater than 210mA / mm 2 or 250mA / mm 2 In other embodiments, the ratio is greater than about 10 mA / mm 2 ~Approx. 1000mA / mm 2 , about 80mA / mm 2 ~about 500mA / mm 2 , about 70mA / mm 2 ~about 300mA / mm 2 , about 70mA / mm 2 ~ approx. 220mA / mm 2 , or about 100mA / mm 2 ~about 200mA / mm 2 It could be.

[0037] Another measure of electrode capacity is found in the relationship between the vent area and the interfacial area, the area between the anode and the cathode. The ratio of these values ​​provides a measure of the relative area of ​​the air access port that allows air access to the cathode compared to the amount of electrode interface that couples the activity of the cathode to the electrolyte and the anode electrochemical reaction. Without being bound by theory, the ratio of the vent area to the interfacial area indicates the relative kinetics of oxygen activation and transport for use with the anode, and transport into the cell versus incorporation into the electrolyte, as determined by the properties of the three-phase boundary at the cathode-anode interface. The interfacial area is a rough estimate of the amount of three-phase boundary required, assuming constant volume, tortuosity, and wettability. If less vent area is required, less oxygen will enter the cell and less oxygen will be available for conversion to hydroxyl radicals and oxygen ions in the electrolyte. It is therefore postulated that the overpotential of the reaction on the anode must be smaller since less excess reactant is required in the electrolyte. Alternatively, there may be high activity at the cathode site for conversion to reactants in the electrolyte. The ratio of the ventilation area to the interface area is approximately 1.0 × 10 -4 or more, or about 1.0 x 10 -4 The ratio of vent area to interface area can be about 1.0×10 -4 ~Approx. 3.0×10 -3 The ratio of vent area to interface area can be about 1.0×10 -3 ~Approx. 3.0×10 -3 In various embodiments, the ratio of vent area to interface area can be about 1.0×10 -3 ~Approx. 3.0×10 -3 , about 1.0×10 -3 ~Approx. 2.4×10 -3 , or about 1.4 × 10 -3 ~Approx. 3.0×10 -3 may be also possible.

[0038] A further measure of cell activity and stability can be found by measuring the ratio of the cell limit current at 1.15V to the cell limit current at 0.9V. The cell limit current at 1.15V represents the maximum current that can be generated by the cell at 1.15V, which is the correct voltage in the operating window of the hearing aid device. The cell limit current at 0.9V represents the maximum current at the lowest correct operating voltage that this battery should see. The 0.9V cell limit voltage represents a kinetic phenomenon that is far from balanced. By studying the ratio of these two values, it is possible to observe that different rate limiting steps and mechanisms are operating at these two potentials, as determined by the battery design. According to various embodiments, cells can be provided in which the ratio of the cell limit current at 1.15V to the cell limit current at 0.9V is greater than about 0.6. In some embodiments, the ratio may be greater than about 0.7 or greater than 0.75. In other embodiments, the ratio may be between about 0.6 and 0.9.

[0039] The cell limiting current at 0.9V also indicates the current that the cell can provide when the current is limited by the availability of oxygen to the cathode. This current is "limited" in two senses: first, because there is less change in current over time after the first approximately 30 seconds when the cell is held at 0.9V (the electrochemical definition), and second, because there is less change in current due to the location of this voltage on the polarization curve of the cell that would result from further drops in voltage below 0.9V. The design of the cell for a particular application selects the size and number of air access ports, as well as the porosity of other material layers through which oxygen must diffuse to reach the reaction sites. The cell needs to have an adequate limiting current to accommodate the desired discharge current range of the cell in use. However, if the limiting current at 0.9V is higher than necessary, the cell will be adversely affected. This adverse effect is because moisture (H2O vapor) and carbon dioxide (CO2) have very similar diffusion properties through the air access ports and the membrane layers. Thus, a higher limiting current at 0.9V serves as a proxy for more diffusion of water vapor and carbon dioxide. Water vapor diffusion in and out of the cell occurs whenever the cell is not in an environment with equilibrium humidity, altering the cell's composition and adversely affecting its performance. Similarly, carbon dioxide is known to dissolve in the electrolyte, reducing ionic conductivity and degrading cell performance. It is therefore desirable for the cell to have the lowest possible limiting current at 0.9V while still accommodating the desired discharge current rate.

[0040] As mentioned above, the limiting current measured at 1.15V is an approximation of the maximum available constant current load of the cell since it is measured at the operating voltage of the cell. It is noteworthy that this measurement is only "limiting" in time, but unlike the limiting current measured at 0.9V, it is sensitive to small changes in voltage since it is on a somewhat flat part of the polarization curve where small changes in voltage result in large changes in current. Thus, a cell with a high ratio of the limiting current at 1.15V to the limiting current at 0.9V is advantageous because it can be designed to provide the same current as a normal cell under the operating conditions of the device while having a lower limiting current at 0.9V and therefore lower moisture and carbon dioxide transport.

[0041] It has now been discovered that in the cells described herein, continuous current can be delivered while the cell has a lower limiting current at 0.9 V than previously required. Only twice the limiting current at 0.9 V is required as the continuous current. Thus, for a current of 6 mA, only a limiting current at 0.9 V of 12 mA is required, and the present cell provides superior results for reduced moisture and carbon dioxide transport.

[0042] The above rules can be modified according to the voltage and current pulse requirements of the present application, but the general principles and design differences still apply. For a normal cell, if a limit current at 0.9V that is twice the maximum continuous current required is appropriate, then for the cell of the present invention, a limit current at 0.9V of only 1.33 times the continuous current is similarly appropriate. In this case, if the required continuous current is 9mA, a normal cell needs to be designed with a limit current at 0.9V of 18mA, whereas the cell of the present invention can be designed with a limit current at 0.9V of 12mA.

[0043] In any embodiment herein, the amphoteric fluorosurfactant may contain a short-chain perfluoro substituent that cannot be broken down to perfluorooctanoic acid. In any embodiment herein, the amphoteric fluorosurfactant may contain a betaine functionality. For example, the amphoteric fluorosurfactant may be represented as a compound of formula (I): [ka] In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 are each independently a hydrogen group, an alkyl group, an alkenyl group, or a cycloalkyl group; X 1 are -C(O)-, -SO2-, and -C(O)NR a -,-SO2NR a -, -CO2-, or -SO2O-, R a is an H group or an alkyl group; m and p are each independently 0, 1, 2, 3, 4, 5, or 6; and n and r are each independently 1, 2, 3, 4, or 5. In some embodiments, R 1 ~R 6 is H and R 7 and R 8 is a C1-C4 alkyl group, n and p are 2, m is 4, 5, or 6, and X 1 is SO2 and r is 1.

[0044] In any embodiment of the present specification, the amphoteric fluorosurfactant may be present in the electrolyte at about 200 ppm to about 20,000 ppm. Thus, in any embodiment of the present specification, the electrolyte may be present at about 500 ppm, about 600 ppm, about 700 ppm, about 800 ppm, about 900 ppm, about 1,000 ppm, about 2,000 ppm, about 3,000 ppm, about 4,000 ppm, about 5,000 ppm, about 6,000 ppm, about 7,000 ppm, about 8,000 ppm, about 9,000 ppm, about 10,000 ppm, or about 12,000 ppm. The amphoteric fluorosurfactant may be present in an amount of about 00 ppm, about 11,000 ppm, about 12,000 ppm, about 13,000 ppm, about 14,000 ppm, about 15,000 ppm, about 16,000 ppm, about 17,000 ppm, about 18,000 ppm, about 19,000 ppm, about 20,000 ppm, or a range between any two of these values ​​(including the endpoints). For example, in any embodiment herein, the amphoteric fluorosurfactant may be present in the electrolyte at about 2000 ppm to about 15000 ppm or about 3000 ppm to about 12000 ppm. As another example, in any embodiment herein, the amphoteric fluorosurfactant concentration in the electrolyte may be about 10,000 ppm.

[0045] The battery may be constructed according to or consistent with the design of a metal-air battery, such as a zinc / silver oxide battery, a zinc / manganese dioxide battery, etc. For example, the battery may be designed to specifications suitable for a metal-air button size battery. Additionally, the shape of the battery may be such that the anode is held in a somewhat flat or dished position.

[0046] The following disclosure through reference to FIG. 1 is provided to aid in understanding, but is not intended to mandate the inclusion of the features described in the metal-air battery of the present technology. However, in any embodiment of the present disclosure, the battery of the present disclosure may be as shown in FIG. 1. FIG. 1 shows that in a cell 10 of the battery, the negative electrode includes an anode can assembly 22 (anode can 24 having an electrochemically reactive anode 26 contained therein) and an insulating gasket 60. The anode can 24 has a base wall 28 and a downwardly extending circumferential side wall 30. The side wall 30 terminates at a circumferential can foot 36. The base wall and the side wall 30 generally define an anode cavity 38 within the anode can 24, which contains the anode 26.

[0047] Anode can 24 may include an alloy of copper including copper and metals such as aluminum, silicon, cobalt, tin, chromium, zinc, and mixtures of any two or more thereof. For example, in any of the embodiments disclosed herein, the entire anode can 24 may include an alloy of copper.

[0048] The cathode 42 includes the area below the separator 74 to the cathode can 44. This area of ​​the cathode 42 includes the porous diffusion layer 57, the cellulose air diffusion layer, and the cathode active layer 72. The cathode can 44 has a bottom 46 and an upstanding circumferential sidewall 47. The bottom 46 has a generally planar inner surface 48, a generally planar outer surface 50, and a periphery 52 defined on the planar outer surface 50. A plurality of air access ports 54 extend through the bottom 46 of the cathode can 44 and provide a path for oxygen to traverse through the bottom 46 and into the adjacent cathode can assembly 40. An air reservoir 55 spaces the cathode can assembly 40 from the bottom 46 and the corresponding air access port 54. The porous diffusion layer 57 and the cellulose air diffusion layer 32 fill the air reservoir 55. The cathode can sidewall 47 has an inner surface 56 and an outer surface 58 .

[0049] As mentioned above, the air access ports 54 define a vent area through which oxygen may enter the cell forming a voltaic cell in which the zinc produces electrical current. In accordance with the surprising observations described herein, it has been discovered that when amphoteric fluorosurfactants are used in the electrolyte of the batteries of the present technology, the minimum required total vent area defined by the air access ports 54 is surprisingly low. As previously discussed, when the metal-air battery is a size 13 cell, the total vent area defined by all of the air access ports within the housing is approximately 0.05 mm 2 ~about 0.1995mm 2 Thus, in any embodiment disclosed herein for a size 13 cell, the total vent area defined by all of the air access ports is approximately 0.05 mm 2 ~about 0.10mm 2 , about 0.06 mm 2 ~about 0.095mm 2 , about 0.06 mm 2 ~about 0.085mm 2 , about 0.07 mm 2 ~ approx. 0.09mm 2 , or about 0.08 mm 2 ~about 0.085mm 2 It could be.

[0050] The anode can assembly 22 is electrically insulated from the cathode can assembly 40 by an insulating gasket 60. The insulating gasket 60 includes a circumferential sidewall 62 disposed between the upright sidewall 47 of the cathode can and the downwardly extending sidewall 30 of the anode can. An insulating gasket foot 64 is generally disposed between the can foot 36 of the anode can and the cathode can assembly 40. An upper portion 66 of the insulating gasket is positioned at the locus where the sidewall 62 of the insulating gasket 60 extends from between the sidewall 30 and the sidewall 47 adjacent the top of the cell.

[0051] Thus, the exterior surface 68 of the cell 10 is defined by a portion of the exterior surface of the top of the anode can 24, a portion of the exterior surface 58 of the sidewall 47 of the cathode can 44, a portion of the exterior surface 50 of the bottom of the cathode can 44, and a portion of the top 66 of the insulating gasket 60.

[0052] The insulating gasket 60 performs at least two primary functions. First, the insulating gasket 60 acts as a seal for the cell 10 to prevent the anode 26 and / or electrolyte from leaking out of the cell between the exterior surface of the sidewall of the anode can 30 and the interior surface 56 of the sidewall of the cathode can 47. Thus, the insulating gasket 60 must possess suitable liquid sealing properties to prevent such leakage. Generally, such properties are available in a variety of elastically deformable thermoplastic polymeric materials.

[0053] Second, the insulating gasket 60 provides electrical insulation to prevent all effective direct electrical contact between the anode can 24 and the cathode can 44. Thus, the sidewall 62 of the insulating gasket 60 must surround the entire circumference of the battery between the exterior and interior surfaces 56, generally from the top of sidewall 47 to the bottom of sidewall 30, to provide electrical insulation properties. Similarly, the foot 64 of the insulating gasket 60 must surround the entire circumference of the cell between the foot 36 of sidewall 30, the bottom of sidewall 47, and the outer periphery of the cathode can assembly 40 to provide electrical insulation properties. The combination of good liquid sealing properties and good electrical insulation properties is typically achieved by molding a known battery grade nylon polymer material into the desired configuration.

[0054] To meet the electrical insulation requirements, the insulating gasket 60 may have good dielectric insulating properties, may have a minimum thickness around the sidewall 62, and may be free of any pinholes or other defects that may allow the transmission of electrical current between sidewall 30 and sidewall 47. An insulating gasket sidewall 62 thickness of about 200 to about 250 microns is typical in conventional electrochemical cells. Thicknesses as thin as 100 microns are found in high performance cells and are acceptable in the cells of the present disclosure using the same elastically deformable thermoplastic nylon material as the thicker insulating gaskets of the prior art.

[0055] Depending on the battery construction to which the insulating gasket is applied, intermediate thicknesses may be selected for some cells, such as, for example, 150 microns, 140 microns, 127 microns, etc. However, where volumetric efficiency of the cell is the driving consideration, preferred thicknesses are as low as, for example, 120 microns or 110 microns to 100 microns. Thus, the lower end of the preferred insulating gasket 60 thickness range for the cell 10 of the present disclosure is about 100 microns. Other insulating methods, possibly using even thinner insulating materials, are possible and are not incompatible with the materials disclosed herein.

[0056] It should be noted that in this design, the inner diameter of the insulator defines the approximate usable interfacial area between the anode and cathode, however, in other cell designs, different components may control the interfacial area, and the concept of interfacial area is still important in that case as well.

[0057] In any of the embodiments disclosed herein, the porous diffusion layer 57 can be a microporous hydrophobic polymeric material, such as a polytetrafluoroethylene (PTFE) membrane about 25 to about 100 microns thick, that allows the passage of air therethrough and is generally impermeable to the battery's electrolyte. For example, the porous diffusion layer 57 can be Teflon™. In any of the embodiments disclosed herein, the porous diffusion layer 57 can be used in combination with the air access port 54 to efficiently transport oxygen to the surface area of ​​the active reaction of the cathode assembly.

[0058] The cellulose air diffusion layer 32 may be located below the porous diffusion layer 57 and may act as a protective lateral air diffusion layer. Specifically, when the cell is powered, the anode can assembly 22 presses down on the separator 74 and the cellulose air diffusion layer 32 helps protect the air access port 54 from being completely covered.

[0059] The active layer 72 may further include a connecting base layer, such as a conductive woven nickel wire layer (not shown) that may interface with the cathode can as a current collector. In any of the embodiments disclosed herein, carbon may form a matrix that surrounds the conductive layer of nickel wire. Nickel may be used for the conductive layer because it exhibits little or no corrosion in the zinc-air cell environment and because nickel is an excellent electrical conductor. In any of the embodiments disclosed herein, the thickness of the cathode assembly between the separator 74 and the porous diffusion layer 57 may be as small as possible.

[0060] The aqueous electrolyte for the metal-air battery of the present technology may include a base, such as sodium hydroxide (NaOH), potassium hydroxide (KOH), or a combination thereof. The electrolyte of any embodiment disclosed herein may include a surfactant system, a corrosion inhibitor (e.g., one or more of indium hydroxide, polyaniline, polyethylene glycol, polypropylene glycol, and lithium hydroxide), a gelling agent (e.g., a polyacrylate polymer), a gas suppressing additive (e.g., one or more of zinc oxide, aluminum hydroxide, LiOH, and calcium bromide), potassium hydroxide, sodium hydroxide, cesium hydroxide, boric acid, sodium borate, potassium borate, sodium stannate, potassium stannate, or a combination of any two or more thereof.

[0061] The surfactant system may include at least one amphoteric fluorosurfactant. For example, the surfactant system may include at least two amphoteric fluorosurfactants. In any embodiment herein, the surfactant system may include one or more amphoteric fluorosurfactants, and one or more corrosion inhibitors (e.g., one or more of indium hydroxide, polyaniline, polyethylene glycol, polypropylene glycol, and lithium hydroxide), gelling agents (e.g., polyacrylate polymers), gas suppression additives (e.g., one or more of zinc oxide, aluminum hydroxide, LiOH, and calcium bromide), potassium hydroxide, sodium hydroxide, cesium hydroxide, boric acid, sodium borate, potassium borate, sodium stannate, and potassium stannate. In any of the embodiments disclosed herein, the surfactant system can be CHEMGUARD® S-111, CHEMGUARD® S-500, CAPSTONE® FS-50, CAPSTONE® FS-51, APFS-14, DYNAX DX3001, ZONYL® FSK, ZONYL® FS-500, or a combination of any two or more thereof.

[0062] The electrolyte and / or surfactant system of any embodiment herein may include additional surfactants, such as hexyldiphenyloxide disulfonic acid, diethylenetriamine, octylphenoxypolyethoxyethanol, compounds of formula (III), or combinations of any two or more thereof. Compounds of formula (III) include: [ka] In the formula, R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , and R 21 are each independently a hydrogen group, an alkyl group, an alkenyl group, or a cycloalkyl group; X 2 is O or S, and X 3is OH or SH, and w is 5 to 50. In any embodiment disclosed herein, R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , and R 21 In any of the embodiments disclosed herein, X 2 may be O. In any of the embodiments disclosed herein, X 3 In any embodiment disclosed herein, w can be 5 to 15. In any embodiment disclosed herein, w can be 5 to 10. In any embodiment disclosed herein, R 13 is C1-C 12 R may be an alkyl group. 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , and R 21 can each be hydrogen, and X 2 can be O, X 3 can be OH and w can be 5 to 15. In any of the embodiments disclosed herein, R 13 can be octyl and w can be 5 to 10. In another embodiment, R 13 is 1,1,3,3-tetramethylbutyl, and w is 5 to 10.

[0063] The electrolyte of any embodiment herein may further include hexyl diphenyl oxide disulfonic acid as part of a hexyl diphenyl oxide disulfonic acid surfactant system. The hexyl diphenyl oxide disulfonic acid surfactant system may reduce voltage suppression. The hexyl diphenyl oxide disulfonic acid surfactant system of any embodiment disclosed herein may have a density of about 9.0 to about 10.0 pounds per gallon, for example, a density of about 9.8 pounds per gallon. The hexyl diphenyl oxide disulfonic acid surfactant system of any embodiment disclosed herein may have a pH of less than about 2.0. The hexyl diphenyl oxide disulfonic acid may have a solubility in water of about 50%.

[0064] The hexyl diphenyl oxide disulfonic acid surfactant system of any embodiment disclosed herein may comprise from about 70% to about 75% by weight of the sulfonated benzene, 1,1'-oxybis-sec-hexyl derivative. In any embodiment herein, the hexyl diphenyl oxide disulfonic acid surfactant system may comprise from about 0% to about 5% by weight, or from about 2% to about 4% by weight of sulfuric acid. The hexyl diphenyl oxide disulfonic acid surfactant of any embodiment disclosed herein may comprise from about 20% to about 30% by weight, or from about 22% to about 28% by weight of water. In an exemplary embodiment, the hexyl diphenyl oxide disulfonic acid surfactant is Calfax® 6LA-70, available from Pilot Chemical Company, 2744 East Kemper Road, Cincinnati, Ohio, 45241, which may also act as a coupling agent and / or HLB adjuster in other embodiments of the present disclosure. Thus, the term "surfactant" should not be viewed in a limiting sense as exemplified by Calfax® 6LA-70, but instead is a description of one of the functions that, for example, hexyl diphenyl oxide disulfonic acid and / or hexyl diphenyl oxide disulfonic acid surfactant systems may provide.

[0065] In any embodiment herein, hexyl diphenyl oxide disulfonic acid may be present in an amount of about 500 ppm to about 5,000 ppm, for example, about 1,000 ppm to about 4,000 ppm, or about 2,000 ppm to about 3,000 ppm. Thus, hexyl diphenyl oxide disulfonic acid may be present in an amount of about 1,000 ppm, about 2,000 ppm, about 3,000 ppm, about 4,000 ppm, or about 5,000 ppm, or any range between any two of these values ​​(including the endpoints). For example, hexyl diphenyl oxide disulfonic acid may be present in an amount of about 3,000 ppm, and as another example, hexyl diphenyl oxide disulfonic acid may be present in an amount of about 4,500 ppm.

[0066] The electrolyte of any embodiment disclosed herein may further include a corrosion inhibitor. The corrosion inhibitor may be used to help maintain a clean zinc surface, thereby increasing cell voltage and efficiency. Both the corrosion inhibitor and the amphoteric fluorosurfactant may provide improved cell voltage and cell performance. The corrosion inhibitor may improve electrical conductivity. The corrosion inhibitor may be present in the electrolyte from about 100 ppm to about 15,000 ppm, for example, from about 200 ppm to about 300 ppm. In any embodiment herein, the corrosion inhibitor may be present in an amount of about 150 ppm, about 200 ppm, about 250 ppm, about 300 ppm, about 350 ppm, or any range between any two of these values, inclusive. In any embodiment herein, the corrosion inhibitor may be present in an amount of about 250 ppm. For corrosion inhibitors only, the ppm amounts are based on the total weight of the electrolyte if the corrosion inhibitor is a liquid at room temperature, or based on the zinc weight of the anode if the corrosion inhibitor is a solid at room temperature.

[0067] The corrosion inhibitor of any embodiment of the present technology may be an aromatic amine polymer, indium hydroxide, polyaniline, polyethylene glycol, polypropylene glycol, lithium hydroxide, lithium hydroxide monohydrate, lithium hydroxide hydrate, or a combination of any two or more thereof. For example, the corrosion inhibitor may include a compound of formula (II): [ka] In the formula, R 9 , R 10 , R 11 , and R 12 are each independently a hydrogen group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted cycloalkyl group, and t is 100 to 500. 9 , R 10 , R 11 , and R 12 Each of R may be hydrogen. In any embodiment disclosed herein, t may be from 100 to 200. In any embodiment disclosed herein, R 9 , R 10 , R 11 , and R 12 may each be hydrogen, and m may be 100-200.

[0068] As discussed above, the corrosion inhibitor may include polyaniline. For example, the polyaniline may be emeraldine polyaniline. The emeraldine form of polyaniline may be neutral and have high stability at room temperature. The polyaniline of any embodiment disclosed herein may be a non-acid doped form of polyaniline and may not be a conductive form of polyaniline. The polyaniline of any embodiment disclosed herein may function as a corrosion inhibitor and / or may provide other benefits that do not limit the polyaniline to functioning only as a corrosion inhibitor. Thus, referring to polyaniline as a "corrosion inhibitor" does not limit the polyaniline to only that particular function. For example, the polyaniline may improve electrical conductivity.

[0069] As discussed above, the corrosion inhibitor may include indium hydroxide. In any embodiment disclosed herein, the indium hydroxide may be present in an amount of about 2,000 ppm to about 4,000 ppm, such as about 2,500 ppm to about 3,500 ppm, or about 2,750 ppm to about 3,250 ppm, based on the total weight of the zinc of the anode. Thus, the indium hydroxide may be present in an amount of about 2,000 ppm, about 2,500 ppm, about 3,000 ppm, about 3,500 ppm, about 4,000 ppm, or in a range between any two of these values, including the endpoints. For example, the indium hydroxide may be present in an amount of about 3,000 ppm, based on the total weight of the zinc of the anode, in any embodiment disclosed herein.

[0070] The electrolyte may include a gelling agent. Any suitable gelling agent in the art may be used without departing from the scope of the present disclosure. The gelling agent may be present in an amount of about 500 ppm to about 1,500 ppm, about 750 ppm to about 1,250, or about 900 ppm to about 1,100 ppm based on the total weight of the electrolyte. Thus, the gelling agent may be present in an amount of about 500 ppm, about 600 ppm, about 700 ppm, about 800 ppm, about 900 ppm, about 1,000 ppm, about 1,100 ppm, about 1,200 ppm, about 1,300 ppm, about 1,400 ppm, or about 1,500 ppm, or in a range between any two of these values ​​(including the endpoints). For example, the gelling agent may be present in an amount of about 1,000 ppm in any of the embodiments disclosed herein. In any of the embodiments disclosed herein, the gelling agent can be a polyacrylic acid polymer, such as a cross-linked polyacrylic acid polymer.

[0071] The electrolyte may include a polyacrylate polymer. The polyacrylate polymer may be present in an amount of about 1,000 ppm to about 5,000 ppm. This may include about 2,000 ppm to about 4,000 ppm, or about 2,500 ppm to about 3,500 ppm. Thus, the polyacrylate polymer may be present in any of the embodiments disclosed herein in an amount of about 2,000 ppm, about 2,500 ppm, about 3,000 ppm, about 3,500 ppm, about 4,000 ppm, or in a range between any two of these values, inclusive. For example, the polyacrylate polymer may be present in an amount of about 2,000 ppm. By way of example, a suitable polyacrylate polymer is a crosslinked polyacrylate polymer.

[0072] Zinc oxide may be present in an amount of about 1% to about 10% by weight of the electrolyte. This may include about 1% to about 8%, 1% to about 5%, about 1.5% to about 5%, or about 2% to about 5% by weight of the electrolyte. Thus, zinc oxide may be present in any embodiment disclosed herein in an amount of about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, or about 4% by weight of the electrolyte, or in a range between any two of these values, inclusive. For example, zinc oxide may be present in an amount of about 2% by weight of the electrolyte. Zinc oxide may provide other benefits that do not limit zinc oxide to functioning solely as a gas suppressing additive, and thus referring to zinc oxide as a "gas suppressing additive" does not limit zinc oxide to only that particular function. For example, zinc oxide in any embodiment disclosed herein may modulate the passivation of the zinc surface.

[0073] The electrolyte may include potassium hydroxide. The potassium hydroxide may be present in an amount of about 20% to about 45% by weight of the electrolyte, such as about 25% to about 40% by weight, or about 30% to about 35% by weight of the electrolyte. In any embodiment disclosed herein, the potassium hydroxide may be present in an amount of about 45%, about 30%, about 25%, or about 20% by weight of the electrolyte, or in a range between any two of these values, inclusive. For example, the potassium hydroxide may be present in an amount of about 33% by weight of the electrolyte.

[0074] The electrolyte may include sodium hydroxide. The sodium hydroxide may be present in an amount of about 20% to about 45% by weight of the electrolyte, for example, about 25% to about 40% by weight, or about 30% to about 35% by weight of the electrolyte. The sodium hydroxide may be present in any of the embodiments disclosed herein in an amount of about 45%, about 30%, about 25%, or about 20% by weight of the electrolyte, or in a range between any two of these values, inclusive. For example, the sodium hydroxide may be present in an amount of about 33% by weight of the electrolyte.

[0075] In any embodiment disclosed herein, the electrolyte of the metal-air battery may include a surfactant system and a corrosion inhibitor, and the surfactant system may include an amphoteric fluorosurfactant. The surfactant system may further include a gas suppressing additive. In any embodiment disclosed herein, the surfactant system may further include hexyldiphenyloxide disulfonic acid, diethylenetriamine, or octylphenoxypolyethoxyethanol, a compound of formula (III), or a combination of any two or more thereof. The gas suppressing additive may include a material such as LiOH or ZnO. In any embodiment disclosed herein, the electrolyte may include about 500 ppm to about 20,000 ppm of the gas suppressing additive. Therefore, the electrolyte may be present at about 500 ppm, about 600 ppm, about 700 ppm, about 800 ppm, about 900 ppm, about 1,000 ppm, about 2,000 ppm, about 3,000 ppm, about 4,000 ppm, about 5,000 ppm, about 6,000 ppm, about 7,000 ppm, about 8,000 ppm, about 9,000 ppm, about 10,000 ppm, about The gas suppressing additive may be included in an amount of about 1,000 ppm, about 12,000 ppm, about 13,000 ppm, about 14,000 ppm, about 15,000 ppm, about 16,000 ppm, about 17,000 ppm, about 18,000 ppm, about 19,000 ppm, about 20,000 ppm, or a range between any two of these values ​​(inclusive).

[0076] The electrolyte of any embodiment disclosed herein may be at a concentration of about 500 ppm, about 600 ppm, about 700 ppm, about 800 ppm, about 900 ppm, about 1,000 ppm, about 2,000 ppm, about 3,000 ppm, about 4,000 ppm, about 5,000 ppm, about 6,000 ppm, about 7,000 ppm, about 8,000 ppm, about 9,000 ppm, about 10,000 ppm, about 11,000 ppm, about 12,000 ppm, about The LiOH may include an amount of about 13,000 ppm, about 14,000 ppm, about 15,000 ppm, about 16,000 ppm, about 17,000 ppm, about 18,000 ppm, about 19,000 ppm, about 20,000 ppm, about 21,000 ppm, about 22,000 ppm, about 23,000 ppm, about 24,000 ppm, about 25,000 ppm, or a range between any two of these values ​​(inclusive).

[0077] The metal-air battery of any embodiment disclosed herein may include a carbon dioxide scrubbing agent to improve cell performance and life. As air enters the cell, the carbon dioxide reacts with the carbon dioxide scrubber to prevent or at least minimize reaction of the carbon dioxide with alkaline components in the electrolyte or on the surface of the air diffusion membrane. The scrubber allows the conductivity of the electrolyte and the porosity of the cathode to be maintained for an extended period of time. The electrolyte of any embodiment disclosed herein may be seeded with a material that preferentially reacts with dissolved carbon dioxide before reacting with the alkali hydroxide present in the electrolyte.

[0078] Exemplary carbon dioxide scrubbers include, but are not limited to, lithium hydroxide, calcium hydroxide, lithium peroxide, lithium oxide, amines, olivine, or other basic hydroxides.

[0079] In any of the embodiments disclosed herein, the carbon dioxide scrubbing agent may be used to coat the inside of the cathode can in the space where the incoming air may encounter the scrubbing agent before contacting the anode active material (i.e., zinc). For example, as shown in FIG. 1, the air reservoir 55 is the void space within the battery cell. The cell is configured such that air enters the cell through the air access port 54 before contacting the diffusion layer 32. Thus, the carbon dioxide scrubbing agent may be applied to the interior surface of the cell within the air reservoir 55 to remove or at least mitigate the carbon dioxide as it enters the cell through the air access port 54. The scrubbing agent may also be embedded within or deposited on any of the cellulose air diffusion layer 32, the cathode 42, or the porous diffusion layer 57. The scrubbing agent may be deposited as a powder, as a film by painting through a solvent that is later removed, or by other practical means.

[0080] In any of the embodiments disclosed herein, the carbon dioxide scrubbing agent may be added to the alkaline electrolyte. In such an embodiment, the scrubbing agent is selected such that the material reacts first with the carbon dioxide while preserving the NaOH or KOH present in the electrolyte. Without being bound by theory, it is believed that when the CO2 enters the zinc-air cell, it dissolves in the aqueous electrolyte, thereby forming carbonic acid. The carbonic acid may then react with the scrubber such that the desired alkalinity of the electrolyte is maintained prior to reaction with the NaOH or KOH present in the electrolyte.

[0081] In any of the embodiments disclosed herein, the carbon dioxide scrubbing agent may be included in the packaging containing the hearing aid cell (according to the present technology) to minimize storage damage from carbon dioxide exposure prior to use of the cell. For example, the packaging may include a chamber intended to hold a zinc-air cell, such as a hearing aid battery, for storage or sale. The packaging may include the carbon dioxide scrubbing agent either as a powder, a coating on the packaging material, or embedded within the plastic or paper that makes up the packaging and chamber forming material.

[0082] The anode includes an anode active material, and an anode can assembly may surround the anode active material. In any of the embodiments disclosed herein, the anode active material may include zinc, and the anode may be referred to as a "zinc anode." In this regard, it should be noted that as used herein, anode "active material" may refer to a single compound that is part of the discharge reaction at the anode of the cell and contributes to the cell's discharge capacity, including impurities that may be present therein, and small amounts of other moieties. Anode "active material" does not include current collectors, electrode leads, etc., that may contain or support the zinc active material.

[0083] Physical modification of the anode, either alone or in combination with the chemical modifications described above, can also improve the service life of the cell. For example, by lowering the diffusion resistance of hydroxide ions, the cell can be efficiently discharged with advantageously lower concentrations of hydroxide ions in the electrolyte than can be used in conventional cells. This can be achieved, for example, by tailoring the particle size distribution of zinc to provide a similar narrow particle size distribution of zinc in the anode, thereby improving the porosity (diffusion paths) of hydroxide ions. In addition to improving the diffusion properties, the particle size distribution of the present disclosure also provides porous sites for ZnO precipitation, thereby delaying the passivation of the anode. This approach is effective for use in the anode of zinc-air battery cells and can be used in combination with other improvements disclosed herein.

[0084] A suitable zinc particle size distribution is one in which at least 70% of the particles have a standard mesh sieved particle size within the 100 micron size range, with the mode of the distribution being from about 100 to about 300 microns. Suitable zinc particle size distributions include those which meet the above test and have a mode of about 100 microns, about 150 microns, or about 200 microns. In any of the embodiments disclosed herein, about 70% of the particles may be distributed in a particle size distribution range narrower than about 100 microns, for example, about 50 microns, or about 40 microns or less.

[0085] The positive electrode may include a cathode can assembly 40, which includes a cathode can 44 and a cathode 42. An exemplary embodiment of the cathode 42 is best seen in FIG. 1. The active layer 72 of the cathode 42 is interposed between a separator 74 and a porous diffusion layer 57. The active layer 72 is preferably about 50 microns to about 1250 microns thick and promotes the reaction between hydroxyl ions in the electrolyte and the cathode oxygen of the air. The separator 74 may include or consist of one or both of a microporous plastic membrane and a microporous cellulose paper. The microporous plastic membrane is about 25 microns thick and is typically made of polypropylene. The paper material is 70 to 90 microns thick and has a basis weight of 20 to 25 g / m. 2 and is typically made of polyvinyl alcohol and a cellulose material. The separator has the primary function of preventing the anode zinc particles from coming into physical contact with the remaining elements of the cathode 42. However, the separator 74 does allow the passage of hydroxyl ions and water therethrough to the cathode assembly. Here, the cathode is an air cathode and the cathode active layer comprises carbon.

[0086] The sidewall 47 of the cathode can 44 is joined to the bottom 46 of the can by an intermediate element 80. The outer surface of the intermediate element 80 extends from its lower end at the periphery 52 of the outer surface 50 of the bottom 46 to its upper end where it joins the outer surface 58 of the sidewall 47 in a generally vertical orientation. The inner surface of the intermediate element 80 is represented at the junction, if any, of the inner surface 48 of the bottom 46 with the inner surface 56 of the sidewall 47. The inner surfaces 48 and 56 may meet at a sharp corner such that the inner surface of the intermediate element is of nominal dimensions. To the extent that the corner material is worked in forming the corner, the corner may be work hardened, whereby the corner structure is strengthened relative to the bottom 46 and sidewall 47 as the corner structure is formed in the intermediate element 80.

[0087] In any of the embodiments disclosed herein, the can / housing may be formed entirely of a metal or alloy having a hydrogen overvoltage similar to that of the cathode (as opposed to plating or cladding the can), so long as sufficient strength and ductility is available from the selected material. In addition to nickel, materials having such hydrogen overvoltage properties include, for example, but are not limited to, cobalt and gold. In some embodiments, such materials may be coated as one or more coating layers onto a core layer, for example, by plating, cladding, or other application process. Materials that provide sufficient strength and ductility may also be used as a single layer material instead of a composite structure. A single layer material includes CRS or other suitable material as the core layer.

[0088] In any of the embodiments disclosed herein, nickel and nickel alloy plated steel strip may be used due to cost considerations and the commercial availability of pre-plated steel strip that generally does not require post plating processes. The metal in the can / housing is preferably both ductile enough to withstand the drawing process and strong and rigid enough to tolerate and otherwise withstand the cell crimping and sealing process as well as provide the primary overall structural strength to the cell / battery.

[0089] In any of the embodiments disclosed herein, the housing may include nickel clad stainless steel, nickel plated cold rolled steel, INCONEL® (a non-magnetic alloy of nickel), pure nickel with minor alloying elements (e.g., Nickel 200 and related series of Nickel 200 alloys such as Nickel 201) (all available from Huntington Alloys), or DURANICKEL® 301 available from Special Metals. For example, the housing may be made of nickel plated stainless steel. Some precious metals may also be used as plating, cladding, or other coatings for the can / housing metals, examples of which are nickel plated steel strip and the coating of mild steel strip plated with nickel after the can is manufactured.

[0090] When multiple layers (e.g., CRS) coated with nickel on both sides are used, the present disclosure contemplates an optional additional (e.g., fourth, fifth, etc.) layer, either between the nickel and the CRS, or between the CRS and the additional layer, of the nickel layer. For example, gold, cobalt, or other good electrical conductors can be deposited on some or all of the exterior surface (outside the nickel layer) of the cathode can after the can is drawn, or after drawing and ironing. Alternatively, such a fourth layer, etc., can be a bond-enhancing layer, for example, between the CRS and the nickel.

[0091] When the can / housing is manufactured using a typical raw material structure of nickel / stainless steel (SST) / nickel / NI / SST / NI as the sheet structure, such sheet structure may be about 0.05 mm to about 0.3 mm. This may include about 0.076 mm to about 0.25 mm, or about 0.1 mm to about 0.15 mm, and thus the thickness may be about 0.05 mm, about 0.076 mm, about 0.1 mm, about 0.13 mm, or about 0.15 mm, or a range between any two of these values ​​(including the end points). For example, the thickness may be about 0.13 mm. In any of the embodiments disclosed herein, each of the nickel layers may represent about 1% to about 10% of the total thickness of such a three-layered metal sheet. This may include about 1.5% to about 9%, about 2% to about 8%, about 2.5% to about 7%, or about 3% to about 6.5% of the total thickness of such a three-layered metal sheet. For example, each of the nickel layers may represent about 2% to about 4% of the total thickness of such a three-layered metal sheet. In any of the embodiments disclosed herein, each of the nickel layers may represent about 2% of the total thickness of such a three-layered metal sheet.

[0092] The invention as described thus far will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the invention. EXAMPLES

[0093] Example 1. A 0.0498 mm anode was used with a zinc anode and an aqueous electrolyte containing (by weight of electrolyte) 31.5% potassium hydroxide, 10,000 ppm amphoteric fluorosurfactant, 1.5% lithium hydroxide, 2% zinc oxide, and 1,000 ppm polyacrylic acid. 2 A size 312 cell of the present technology was prepared having a total vent area of ​​0.1329 mm. A comparative "standard" cell was prepared, where the standard cell did not contain any amphoteric fluorosurfactant and had a total vent area of ​​0.1329 mm. 2The cells were similarly prepared, except that the cells were discharged at 10 / 2mA at 80% RH (relative humidity) as per ANSI / IEC testing, and the technology cells exhibited approximately 15% improvement in capacity compared to the comparative "standard" cells.

[0094] Example 2. Using a zinc anode and aqueous electrolyte containing potassium hydroxide, the amphoteric fluorosurfactant of Example 1, lithium hydroxide, and the polyacrylic acid of Example 1, a 0.0998 mm 2 A size 13 cell of the present technology was prepared having a total vent area of ​​0.1295 mm. A comparative "standard" cell was prepared as follows: the standard cell contained no amphoteric fluorosurfactant and had a total vent area of ​​0.1295 mm. 2 The cells were discharged at 12 / 3 mA at 80% RH (relative humidity) as per ANSI / IEC testing, and the technology cells exhibited approximately 7% improvement in capacity compared to the comparative "standard" cells (Figure 2).

[0095] Example 3. Using a zinc anode and aqueous electrolyte containing potassium hydroxide, the amphoteric fluorosurfactant of Example 1, lithium hydroxide, and the polyacrylic acid of Example 1, a 0.0660 mm 2 A size 312 cell of the present technology was prepared having a total vent area of ​​0.0869 mm. A comparative "standard" cell was prepared, where the standard cell did not contain any amphoteric fluorosurfactant and had a total vent area of ​​0.0869 mm. 2 The cells were similarly prepared, except that the cells were discharged at 10 / 2 mA at 80% RH (relative humidity) as per ANSI / IEC testing, and the technology cells exhibited approximately 13% improvement in capacity compared to the comparative "standard" cells (Figure 3).

[0096] Example 4. Using a zinc anode and aqueous electrolyte containing potassium hydroxide, the amphoteric fluorosurfactant of Example 1, lithium hydroxide, and the polyacrylic acid of Example 1, a 0.0660 mm 2A size 312 cell of the present technology was prepared having a total vent area of ​​0.0869 mm. A comparative "standard" cell was prepared, where the standard cell did not contain any amphoteric fluorosurfactant and had a total vent area of ​​0.0869 mm. 2 The cells were similarly prepared, except that the cells were discharged at 10 / 2 mA at 20% RH (relative humidity) as per ANSI / IEC testing, and the technology cells exhibited approximately 4% improvement in capacity compared to the comparative "standard" cells (Figure 4).

[0097] Example 5. To further illustrate the contribution of the electrolyte itself to the performance of the batteries of the present technology, three aqueous electrolytes were prepared and evaluated as follows. The three electrolytes were: (1) an aqueous electrolyte containing 33% potassium hydroxide (by weight of the electrolyte) and 2% zinc oxide (by weight of the electrolyte); (2) an aqueous electrolyte comprising 33% potassium hydroxide (by weight of the electrolyte), 2% zinc oxide (by weight of the electrolyte), and 7,500 ppm of a carboxylated amine surfactant; and (3) An aqueous electrolyte of the present technology comprising 33% potassium hydroxide (by weight of electrolyte), 2% zinc oxide (by weight of electrolyte), and 10,000 ppm amphoteric fluorosurfactant. The cathodic performance resulting from the use of electrolyte was tested independently from the anodic performance by placing a pure zinc reference electrode in the solution close to the cathode (note: the same distance from the cathode was used for all tests), with the cathode having unrestricted air access on one side and exposed to electrolyte on the other side (a "cathode half-cell"). Then, a current of 1 mA / cm was applied. 2 and 5mA / cm 2 A current draw of 0.01 μm was applied to the cathode and the potential was recorded for each of the above electrolytes relative to a pure zinc reference. As shown in Figure 5, the aqueous electrolyte (3) of the present technology exhibited improved behavior with less voltage drop by drawing the same current over the aqueous electrolytes (1) and (2).

[0098] Example 6. To further illustrate the difference between the present technology and the prior art, a number of size 13 cells of each type were tested for current limiting at 1.15V and 0.9V. It is observed that the ratio of the limiting current at 1.15V to the limiting current at 0.9V is greater for the present technology than for the commercial cell. Figure 6 shows the ratio for both cell types. To investigate further, the limiting current at 1.15V was plotted against the limiting current at 0.9V for several cells of each type. It is observed that both limiting currents, although different from cell to cell, are correlated to each other and have a relatively constant ratio, which is characteristic of the present technology and the commercial cell.

[0099] Example 7. A size 13 cell was discharged at a constant current (as shown in FIG. 8). The cell of the present technology has a current limit at 0.9V of 12mA. When discharged at a rate of 4mA, or one third of the current limit at 0.9V, it delivers a voltage greater than 1.2V throughout the majority of the discharge. This is particularly important since many practical devices send a "battery low" warning to the user when the voltage falls below about 1.1V.

[0100] When a cell of the present technology is discharged at 6 mA, or half the limiting current at 0.9V, it can still deliver greater than 1.17V throughout the first half of the discharge.

[0101] In comparison, a commercially available cell with a limiting current at 0.9 V of 18 mA discharged at 6 mA reflects a current drain equal to one-third of the limiting current at 0.9 V, a lower voltage than current technology provides. In addition, the higher limiting current results in more moisture and carbon dioxide transport, which is detrimental to the cell, especially under low-rate conditions where discharge times are longer.

[0102] Example 8. In another test, it is found that the present technology allows for even smaller vent areas. Using a zinc anode and aqueous electrolyte containing potassium hydroxide, the amphoteric fluorosurfactant of Example 1, lithium hydroxide, and the polyacrylic acid of Example 1, a vent area of ​​0.0330 mm 2 ~0.0869mm2 Size 312 cells of the present technology were prepared with three different total vent areas: 10 / 2 mA at 50% RH (relative humidity) per ANSI / IEC testing, and 5 / 2 mA at 50% RH (relative humidity) per ANSI / IEC testing, and the cells of the present technology exhibited no statistical difference in capacity over the range of total vent areas tested (FIGS. 9, 10).

[0103] Example 9. Potassium hydroxide, amphoteric fluorosurfactant of Example 1, lithium hydroxide, and polyacrylic acid of Example 1 were used to measure the electrical conductivity of a zinc anode and aqueous electrolyte to measure 0.0499 mm 2 ~0.1295mm 2 Size 13 cells of the present technology were prepared with three different total vent areas ranging from 12 / 3 mA at 50% RH (relative humidity) per ANSI / IEC testing, and 5 / 3 mA at 50% RH (relative humidity) per ANSI / IEC testing, and the cells of the present technology exhibited no statistical difference in capacity over the range of total vent areas tested (FIGS. 11, 12).

[0104] While particular embodiments have been shown and described, it is to be understood that changes and modifications can be made by those skilled in the art without departing from the technology in its broader aspects as defined in the following claims.

[0105] The embodiments illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations not specifically disclosed herein. Thus, for example, terms such as "comprising," "including," "containing," and the like, should be read broadly and without limitation. Additionally, the terms and expressions used herein are used as terms of description, not limitation, and in the use of such terms and expressions, there is no intention to exclude any equivalents of the shown and described features or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase "consisting essentially of" will be understood to include the elements specifically recited, as well as additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase "consisting of" excludes any elements not specified.

[0106] The present disclosure should not be limited in terms of the specific embodiments described in this application. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope thereof. In addition to those recited herein, functionally equivalent methods and compositions within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure should be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to particular methods, reagents, compounds, compositions, or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0107] Additionally, where features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual members or subgroups of members of the Markush group.

[0108] As will be understood by those skilled in the art, for any or all purposes, especially in terms of providing a written description, all ranges disclosed herein also include any and all possible subranges and combinations of those subranges. Any recited range can be easily recognized as fully describing and allowing the same range to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be easily broken down into a lower third, a middle third, an upper third, etc. As will also be understood by those skilled in the art, all language such as "up to," "at least," "greater than," "less than," etc. refers to a range that includes the recited numbers and can then be broken down into subranges as discussed above. Finally, as will be understood by those skilled in the art, a range includes each individual member.

[0109] All publications, patent applications, issued patents, and other documents mentioned herein are herein incorporated by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions contained in the texts incorporated by reference are excluded to the extent they conflict with definitions in the present disclosure.

[0110] It is understood that the present technology may include, but is not limited to, the features and combinations of features recited in the following lettered paragraphs, and that the following paragraphs should not be construed as limiting the scope of the claims appended hereto or as mandating that all such features must necessarily be included within the scope of such claims.

[0111] Other embodiments are within the scope of the following claims.

Claims

1. A battery comprising an air cathode, an anode, an aqueous electrolyte, and a housing, wherein the housing comprises one or more air access ports defining a total ventilation area, wherein the battery exhibits a cell limiting current at 1.15 V, The ratio of the cell limiting current at 1.15 V to the total ventilation area is greater than about 100 mA / mm 2 and greater than and wherein the aqueous electrolyte comprises an amphoteric fluorosurfactant.

2. The ratio is about 150 mA / mm 2 The battery according to claim 1, which is greater than

3. The ratio is about 250 mA / mm 2 The battery according to claim 1, which is greater than

4. wherein the ratio is about 100 mA / mm 2 to about 1000 mA / mm 2 The battery according to claim 1, wherein the ratio is as defined above.

5. The battery according to claim 1, having an approximate nominal diameter of 8 mm and an approximate nominal height of 5.4 mm.

6. The battery according to claim 1, having an approximate nominal diameter of 8 mm and an approximate nominal height of 3.6 mm.

7. The battery has a nominal external volume of about 180 mm 3 to about 270 mm 3 The battery according to claim 1, having the above characteristics.

8. The nominal electrode interface area of the battery is about 35 mm 2 The battery according to claim 1, wherein the nominal electrode interface area is as described above.

9. The total ventilation area is about 0.030 mm 2 to about 0.115 mm 2 The battery according to claim 1, wherein the total ventilation area is about 0.030 mm to about 0.115 mm

10. The battery according to claim 1, wherein the cell limiting current at 1.15 V is from about 4 mA to about 15 mA.

11. A battery comprising an air cathode, an anode, an aqueous electrolyte, and a housing, The housing includes one or more air access ports that define a total ventilation area, and the total ventilation area is from about 0.030 mm 2 to about 0.115 mm 2 and wherein the battery exhibits a cell limiting current at 0.9 V, wherein the battery maintains a voltage of 1.17 V or more through 50% of its theoretical discharge capacity when discharged at a current equal to half of the cell limiting current, and wherein the aqueous electrolyte comprises an amphoteric fluorosurfactant.

12. The battery according to claim 11, having an approximate nominal diameter of 8 mm and an approximate nominal height of 5.4 mm.

13. The battery according to claim 11, having an approximate nominal diameter of 8 mm and an approximate nominal height of 3.6 mm.

14. The battery according to claim 11, wherein the cell limiting current at 1.15 V is from about 4 mA to about 15 mA.

15. A battery comprising an air cathode, an anode, an aqueous electrolyte, and a housing, The housing includes one or more air access ports that define a total ventilation area, the total ventilation area being from about 0.030 mm 2 to about 0.115 mm 2 and wherein the battery exhibits a cell limiting current at 0.9 V, wherein the battery maintains a voltage of 1.20 V or more through 50% of its theoretical discharge capacity when discharged at a current equal to one third of the cell limiting current, and wherein the aqueous electrolyte comprises an amphoteric fluorosurfactant.

16. The battery according to claim 15, having an approximate nominal diameter of 8 mm and an approximate nominal height of 5.4 mm.

17. The battery according to claim 15, having an approximate nominal diameter of 8 mm and an approximate nominal height of 3.6 mm.

18. The battery according to claim 15, wherein the cell limiting current at 1.15 V is from about 4 mA to about 15 mA.

19. A battery comprising an air cathode, an anode, an aqueous electrolyte, and a housing, The housing includes one or more air access ports that define a total ventilation area. The battery exhibits a cell limiting current at 0.9 V and a cell limiting current at 1.15 V. The ratio of the cell limiting current at 1.15 V to the cell limiting current at 0.9 V is greater than about 0.

6. The aqueous electrolyte contains an amphoteric fluorine surfactant, the battery. The battery according to claim 19, wherein the ratio is greater than about 0.

75. The battery according to claim 19, wherein the ratio is from about 0.6 to about 0.

9. The battery according to claim 19, having a nominal diameter of about 8 mm and a nominal height of about 5.4 mm. The battery according to claim 19, having a nominal diameter of about 8 mm and a nominal height of about 3.6 mm. The battery according to claim 19, wherein the cell limiting current at 1.15 V is from about 4 mA to about 15 mA. A battery comprising an air cathode, an anode, an aqueous electrolyte, and a housing, The housing includes one or more air access ports that define a total ventilation area. The battery has an interfacial surface area between the anode and the cathode. The aqueous electrolyte contains an amphoteric fluorine surfactant, the battery. The battery has a nominal external volume of about 180 mm 3 to about 270 mm 3 The battery according to claim 19, which has such a volume range The battery according to claim 28, having a nominal diameter of about 8 mm and a nominal height of about 5.4 mm. The battery having a nominal electrode interface area of about 35 mm 2 The battery according to claim 19, wherein the battery has a nominal electrode interface area of about 35 mm The battery according to claim 28, having a nominal diameter of about 8 mm and a nominal height of about 3.6 mm. The total ventilation area is about 0.030 mm 2 to about 0.13 mm 2 The battery according to claim 19, wherein the total ventilation area is as defined above. ​ ​ ​ ​ ​ ​ The ratio of the ventilation area to the interfacial area is about 3×10 -3 or less, provided that when the battery is a size 13 battery, the ratio is about 2.4×10 -3 or less, ​ ​ The ratio is from about 1.0×10 -3 to about 3.0×10 -3 and the battery is not a size 13 battery, the battery according to claim 28. ​ The ratio is about about 1.0×10 -3 to about 2.4×10 -3 The battery according to claim 28, wherein the ratio is as described above ​ The ratio is about about 1.4×10 -3 to about 3.0×10 -3 and the battery is not a size 13 battery, the battery according to claim 28. ​ ​ ​ ​ ​ The battery has a nominal external volume of about 180 mm 3 to about 270 mm 3 The battery according to claim 28, having the same. ​ The battery according to claim 28, wherein the battery has a nominal electrode interface area of about 25 to 50 mm 2 . ​ The total ventilation area is about 0.030 mm 2 to about 0.115 mm 2 The battery according to claim 28, wherein the total ventilation area is as defined above.

Images