JP2008502118A - Electrochemical cell - Google Patents

Abstract

  An electrochemical cell and a method for manufacturing the cell are disclosed. The present invention relates to an electrochemical cell comprising a housing, a negative electrode in the housing, a positive electrode in the housing, the positive electrode containing a catalyst and wax, and a separator between the negative electrode and the positive electrode. I will provide a.

Description

  The present invention relates to an electrochemical cell, such as a metal-air cell, and a method for manufacturing the cell.

  Electrochemical cells are usually used as an electrical energy source. In general, a battery contains a negative electrode and a positive electrode. The negative electrode contains an active material that can be oxidized (eg, zinc particles), and the positive electrode contains an active material that can be reduced (eg, manganese dioxide). The active material of the negative electrode can reduce the active material of the positive electrode. In order to prevent a direct reaction between the active material of the negative electrode and the active material of the positive electrode, both electrodes are electrically separated from each other by a separator.

  When a battery is used as an electrical energy source in a device, electrical contact can occur at the electrodes, allowing electrons to flow through the device, and a power supply can be generated by respective oxidation and reduction reactions. The electrolyte (eg, potassium hydroxide solution) in contact with the electrodes contains ions that flow through the separator between the electrodes to maintain the overall charge balance of the battery during discharge.

  In one type of electrochemical cell, the so-called metal-air cell, oxygen is reduced at the positive electrode and metal is oxidized at the negative electrode. Oxygen can be supplied from the atmosphere outside the cell to the cathode through one or more air holes in the cell housing.

  In one aspect, the invention features an electrochemical cell, such as a metal-air cell, that includes a positive electrode having a wax. As described below, waxes can enhance battery performance, for example, by improving battery shelf life. For example, at low humidity, the wax provides a barrier that reduces the evaporation (“drying”) of the liquid in the battery and reduces the occurrence of carbonation (eg, carbonate formation from the hydroxide electrolyte). can do. At high humidity, the wax can provide a barrier that reduces the amount of water from the air that can diffuse into the cell and concentrate to submerge the cell. Both carbonation and water immersion can block catalyst sites within the positive electrode, thereby reducing battery performance. The wax can also seal cracks or gaps in the positive electrode, which can improve the mechanical properties (eg, strength) of the electrode.

  In another aspect, the present invention comprises a housing, a negative electrode in the housing, a positive electrode in the housing, the positive electrode comprising a catalyst and a wax, and a separator between the negative electrode and the positive electrode. Features an electrochemical cell.

  Embodiments may include one or more of the features described below. The positive electrode has a first portion including a first wax concentration and a second portion including a second wax concentration lower than the first concentration. The second part is between the first part and the negative electrode. The positive electrode has a first portion containing a wax and a second portion substantially free of wax.

  The positive electrode can have a first portion that includes wax, the first portion having a thickness of less than about 0.1 mm. The positive electrode can have a first portion that includes a wax, and the thickness of the first portion is less than about 20% of the thickness of the positive electrode. The positive electrode can have less than about 20% by weight wax.

  The positive electrode may have a first portion and a second portion disposed outside the first portion, the first portion having a lower wax concentration than the second portion. The positive electrode may have an inner surface that is substantially free of wax. The positive electrode can have a first layer that includes wax and a second layer that is substantially free of wax, the second layer being between the first layer and the negative electrode. The positive electrode may include a first layer having a first wax concentration and a second layer having a second concentration lower than the first wax concentration, wherein the second layer includes the first layer and the negative electrode. between.

  The wax can be distributed almost throughout the positive electrode.

  The wax may include hexatriacontane, octacosan, carnauba wax, beeswax, cinnabar wax, and / or montan wax.

  The positive electrode can further include a binder. The catalyst can include manganese oxide and the binder can include polytetrafluoroethylene.

  The battery can be a metal-air battery, an air-assisted battery, or an alkaline battery.

  In another aspect, the invention provides a housing defining an air passage opening, a negative electrode in the housing, the negative electrode comprising zinc, the positive electrode in the housing, and the positive electrode comprising manganese oxide and wax. An electrochemical cell comprising and comprising a separator between the negative electrode and the positive electrode is featured.

  Embodiments may include one or more features described below. The positive electrode has a first portion that includes manganese oxide and wax, and a second portion that includes manganese oxide and is substantially free of wax, the second portion being between the first portion and the negative electrode. The positive electrode has a first portion including manganese oxide and a first wax concentration, and a second portion including manganese oxide and a second wax concentration lower than the first concentration, wherein the second portion is the first portion. And between the negative electrode. The positive electrode has less than about 20% by weight wax. The wax may include hexatriacontane, octacosan, carnauba wax, beeswax, cinnabar wax, and / or montan wax. The battery can be a metal-air battery or an air-assisted battery.

  In another aspect, the present invention further focuses on a method of manufacturing an electrochemical cell. The method includes incorporating wax into a portion of the positive electrode having a catalyst and incorporating the positive electrode into the battery.

  The method can further include melting the wax; applying a solid wax to the surface of the positive electrode; contacting the wax-containing substrate with the positive electrode; and / or laminating the wax to the positive electrode. .

  Other aspects, features, and advantages of the invention will be apparent from the drawings, description, and claims.

  Referring to the figures, an electrochemical cell 10 (a metal-air button cell, as shown) includes a housing 12 defined by a negative electrode can 14 and a positive electrode can 16 that is crimped together with the can 14. The positive electrode can 16 has one or more air passage openings 18 to allow air to enter and exit the battery 10. The battery 10 accommodates a negative electrode 20 and a positive electrode 22 inside the housing 12. An electrolyte such as KOH is dispersed throughout battery 10 to provide charge balance.

  The battery 10 further includes an insulator 24, a separator 26, a membrane 28, and an air disperser 30. An insulator 24 is positioned between the cans 14 and 16 so that the cans can function as the negative and positive terminals of the battery 10, respectively. Separator 28 is positioned between negative electrode 20 and positive electrode 22, thereby preventing electrical contact between the electrodes. The membrane 28 serves to prevent the electrolyte in the negative electrode 20 from leaking out of the battery 10. The air disperser 30 is positioned between the air passage opening 18 and the positive electrode 22.

  The positive electrode 22 includes positive electrode plaque and wax. The positive plaque may be a relatively porous structure composed of a catalyst and a cured mixture of carbon particles and binder. In certain embodiments, the wax forms a layer below the outer surface of the positive electrode 22. As shown in FIG. 1, the outer surface of the positive electrode 22 is a surface adjacent to the membrane 28 that faces the inner surface illustrated adjacent to the separator 26.

  Without being bound by theory, the wax can enhance the performance of the battery 10, for example, by improving the shelf life of the battery. For example, at low humidity, the wax can provide a barrier that reduces the amount of water from the electrolyte that can diffuse through the cathode 22 and evaporate from the battery 10. The loss of water can dry the battery 10 and concentrate an electrolyte such as potassium hydroxide. The concentrated potassium hydroxide is more likely to react with carbon dioxide entering the battery 10 to form potassium carbonate, which blocks the catalytic site of the positive electrode 22 and the movement of oxygen between the air and the catalytic site. Sometimes. As a result, the performance of the battery 10 is reduced. At high humidity, the wax can provide a barrier that reduces the amount of water from the air that can diffuse into the battery 10 and condense on the cathode 22. The condensed water can prevent oxygen from reaching the catalytic site of the positive electrode and / or can submerge the positive electrode, both of which can reduce the performance of the battery 10.

In a preferred embodiment, the wax is a material that is a plastic solid at ambient temperature (eg, battery operating temperature) and becomes a low viscosity liquid when subjected to relatively high temperatures (eg, above about 80 ° C.). is there. The wax can include a hydrocarbon material having hydrophobic properties. The hydrophobic nature of the wax may help prevent water from diffusing through the cathode 22 (eg, repel water). At the same time, the wax allows oxygen from the air to diffuse to the cathode 22, for example, to the extent that battery performance is not substantially adversely affected. For example, a positive electrode with wax has at least 70% of the current density of a substantially identical electrode without wax (e.g., approximately ≧ 75%, approximately ≧ 80%, approximately ≧ 85%, approximately ≧ 90%, or approximately ≧ 95%). Examples of waxes include from standard hydrocarbons (eg, alkanes) to materials that are a mixture of hydrocarbons and reactive functional species. Suitable waxes include hexatriacontane (C ₃₆ H ₇₄ ), octacosane, carnauba wax powder (Stral & Pitsch, Inc.), beeswax, cinna wax, and montan wax. . Other waxes are described in the Encyclopedia of Chemical Technology, 4th edition, volume 25, pages 614-626. In some embodiments, the wax is solid at room temperature and has a melting point of about 80 ° C. or higher (eg, about 100 ° C. or higher). In some embodiments, the wax has a viscosity in the range of about 50 to about 3500 mm ² / s (cSt) when the wax is melted. A mixture of two or more waxes can be used in the positive electrode.

  The wax can be applied to the positive plaque using conventional techniques. For example, wax powder or particles can be applied to the positive plaque using techniques such as powder coating, spray coating, electrostatic spraying, and / or brushing. The size of the powder can range from about 10 nanometers to about 1 mm. The wax can then be air dried if desired, and the plaque is heated, for example, at about 100 ° C. to about 5 ° C., for example by placing the wax-coated plaque in an oven to a temperature above the melting point of the wax. For a minute). As a result, the molten wax can penetrate the pores and / or grooves of the positive plaque (eg, outside the plaque). When the electrode plaque is removed from heating, the wax may solidify inside the plaque. Alternatively or in addition, a wax on a substrate such as paraffin paper can be applied (eg, laminated) to the electrode plaque. When the laminated plaque is heated, the wax can penetrate the plaque and the substrate can be removed (eg, exfoliated) after cooling and solidification. In other embodiments, more than one wax application can be made. For example, multiple layers or multiple layers of wax, such as different compositions, different thicknesses, increase or decrease hydrophobicity, can be applied using multiple applications.

  The amount of wax in the positive electrode 22 can be varied. The amount of wax can be a function of, for example, the type of wax, the method used to apply the wax, the type of electrochemical cell, the desired performance, and / or the viscosity. In some embodiments, the cathode 22 includes less than 20% by weight wax. For example, the positive electrode 22 has 2 wt% or more, 4 wt% or more, 6 wt% or more, 8 wt% or more, 10 wt% or more, 12 wt% or more, 14 wt% or more, 16 wt% or more, or 18 wt%. % Wax and / or 20% or less, 18% or less, 16% or less, 14% or less, 12% or less, 10% or less, 8% or less, 6% or less, 4% or less % Or less, or 2% or less by weight of wax may be included. In some embodiments, the wax thickness is less than about 0.1 mm (eg, less than about 0.08 mm, less than about 0.06 mm, less than about 0.04 mm, less than about 0.02 mm, or less than about 0.01 mm). ). The thickness of the wax is less than about 20% of the total thickness of the positive electrode 22 (eg, less than about 18%, less than about 16%, less than about 14%, less than about 12%, less than about 10%, less than about 8%, Less than about 6%, less than about 4%, or less than about 2%).

  The wax can be applied to any part of the positive electrode 22. For example, the wax can be applied to the entire outer surface and / or the entire inner surface of the positive electrode 22. Wax can be applied only to selected portions of the positive electrode 22. For example, the portion of the electrode 22 adjacent to the air passage opening 18 may include wax while the other portions may be substantially free of wax. The portion near the opening 18 may have a relatively large amount of wax, but the portion away from the opening may have little or a reduced degree of wax. The amount of wax applied to the positive electrode 22 can be varied, for example, by using multiple application steps with appropriate masking techniques. In certain embodiments, a wax (eg, wax powder) can be blended with a positive electrode mixture (described below) such that the wax is dispersed throughout the positive electrode 22. In some cases, for example, if the wax is sufficiently porous that it does not adversely affect air diffusion, a layer of wax may be applied to the surface of the positive electrode without melting the wax into the positive electrode. it can.

  In some embodiments, the wax forms one or more separate portions (eg, layers) between the inner and outer surfaces of the positive plaque. For example, the wax layer can be applied to the first positive plaque as described above. The wax layer can be melted into the first plaque or the layer can be unmelted. The first plaque containing wax can then be combined with the second positive plaque to form the final positive plaque. Bonding techniques include pressure forming, lamination, and / or heat calendering as described in US Pat. No. 6,368,365. The above process can be repeated to form an electrode plaque having two or more portions or layers of wax. The wax portions can have the same or different composition, thickness, coverage, and the like.

  Next, when considering positive plaques, the plaques are blended with a catalyst, carbon particles and a binder to form a positive electrode mixture, which is then coated on a current collector such as a metal mesh screen. Can be formed. After the positive electrode mixture is cured, the mixture can be heated to remove residual volatiles. When the positive electrode 22 is incorporated into the battery 10, the current collector can be placed in electrical contact with the positive electrode can 16.

The active cathode mixture can include a catalyst for reducing oxygen (eg, a manganese compound), carbon particles, and a binder. Suitable catalysts include manganese oxides such as Mn ₂ O ₃ , Mn ₃ O ₄ , MnO ₂ , for example, by heating manganese nitrate or by reducing potassium permanganate. Can be prepared. The positive electrode mixture can include about 0% to about 10%, such as about 3% to about 5%, by weight of catalyst. Mixtures of different catalysts can also be used.

  The carbon particles are not limited to any particular type of carbon. Examples of carbon include Black Pearls 2000, Vulcan XC-72 (Cabot Corp., Billerica, Mass.), Shawinigan Black (Chevron) (Chevron, San Francisco, California), Printex, Ketjen Black (Akzo Nobel, Chicago, Illinois), and Calgon PWA (Calgon Carbon, Pittsburgh, PA). The positive electrode mixture can include about 30 wt% to about 70 wt% carbon, such as about 50 wt% to about 60 wt% carbon. It is also possible to use a mixture of different carbon particles.

  Examples of binders include polyethylene powder, polyacrylamides, Portland cement, and fluorocarbon resins (eg, polyvinylidene fluoride and polytetrafluoroethylene). An example of a polyethylene binder is sold under the trade name Coathylene HA-1681 (Hoechst). The positive electrode mixture can include about 10% to 40%. For example, the mixture may comprise about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, or about 35% or more binder, and / or about It may have 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, or about 15% or less binder.

  In some embodiments, some or all of the binder is replaced with one or more waxes. For example, the positive electrode mixture may contain up to about 40% of one or more waxes if the porosity of the positive electrode plaque is maintained and sufficient air diffusion can be provided (eg, without wax agglomeration or pore clogging). Can be included. Of the total amount of binder and wax in the positive plaque, the wax is about 10% or more, about 20% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 70%. Or more, about 80% or more, about 90% or more, or about 100% or more, and / or about 100% or less, about 90% or less, about 80% or less, about 70% or less, about 60% or less, about 50% Hereinafter, about 40% or less, about 30% or less, about 20% or less, or about 10% or less can be constituted.

On the outer surface of the positive electrode 22, a film 28 is disposed adjacent to the positive electrode. Membrane 28 is air permeable and substantially liquid impermeable. The membrane 28 (eg, PTFE membrane) helps to maintain a constant humidity level within the battery 10. Membrane 28 also includes a prevent the electrolyte from leaking from the battery 10, CO ₂ helps to prevent from entering into the battery.

  Air dispenser 30 is adjacent to membrane 28. The air dispenser 30 can be a porous or fibrous material (eg, porous paper) and serves to maintain an air diffusion space between the membrane 28 and the positive electrode can 16.

  On the inner surface of the positive electrode 22, a separator 26 is installed adjacent to the positive electrode. Separator 26 can be a porous electrically insulating polymer (eg, polypropylene), which can contact the electrolyte with positive electrode 22.

  The negative electrode 20 is on the other side of the separator 26. The negative electrode 20 contains a mixture of zinc and an electrolyte. The zinc and electrolyte mixture may include a gelling agent that can help reduce electrolyte leakage from the battery and suspend the zinc particles in the negative electrode.

  The zinc material may be zinc powder alloyed with lead, indium, aluminum or bismuth. For example, zinc can be alloyed with about 400-600 ppm (eg, 500 ppm) lead, 400-600 ppm (eg, 500 ppm) indium, or about 50-90 ppm (eg, about 70 ppm) aluminum. The zinc material can include lead and indium and aluminum, lead and indium, or lead and bismuth. Alternatively, the zinc may include lead without other metal additives. The zinc material may be air blown zinc or air spun zinc. Suitable zinc particles are, for example, U.S. Patent Application (USSN) 09 / 156,915 (filed September 18, 1998), U.S. Patent Application (USSN) 08 / 905,254 (August 1997). And US patent application (USSN) 09 / 115,867 (filed July 15, 1998), each of which is incorporated by reference in its entirety.

The zinc particles can be spherical or non-spherical. For example, the zinc particles can be acicular (having an aspect ratio of at least 2). The zinc material contains a majority of particles with dimensions of 60 mesh to 325 mesh. For example, the zinc material can have the following particle size distribution:
0-3% by weight on a 60 mesh screen;
40-60 on a 100 mesh screen;
30-50% by weight on a 200 mesh screen;
0-3% by weight on a 325 mesh screen; and 0-0.5% by weight on a pan.

  Suitable zinc materials include Union Miniere (Overpelt, Belgium), Duracell (USA), Noranda (USA), Grillo (Germany) ) Or zinc available from Toho Zinc (Japan).

  The gelling agent can be a polyacrylate absorbent. The polyacrylate absorbent has an absorbent skin with less than about 30 grams of saline per gram of gelling agent, as measured in US Pat. No. 4,541,871, incorporated herein by reference. . The negative electrode gel may include less than 1% zinc of the gelling agent by dry weight in the negative electrode mixture. The gelling agent content can be from about 0.2% to 0.8%, such as from about 0.3% to 0.6%, or about 0.33% by weight. The polyacrylate absorbent can be sodium polyacrylate made by suspension polymerization. The preferred sodium polyacrylate has an average particle size of about 105 to 180 microns and a pH of about 7.5. Suitable gelling agents are described, for example, in US Pat. No. 4,541,871, US Pat. No. 4,590,227, or US Pat. No. 4,507,438.

  In certain embodiments, the negative electrode 20 can include a nonionic surfactant. The surfactant can be a nonionic phosphate surfactant coated on the zinc surface, such as a nonionic alkyl phosphate or a nonionic aryl phosphate (eg, Rohm & Haas). RA600 or RM510 available from). The negative electrode 20 may include about 20 to 100 ppm of a surfactant coated on the surface of the zinc material. The surfactant can function as a gas generation inhibitor.

  The electrolyte may be an alkaline aqueous solution (eg, potassium hydroxide solution). The electrolyte can include about 30-40% (eg, 35-40%) potassium hydroxide. The electrolyte may also include about 1-2% zinc oxide.

  In some embodiments, the negative electrode can 12 can include a tri-clad material or a bi-clad material. The two-layer cladding material can be stainless steel with a copper inner surface. The tri-layer cladding material may be composed of stainless steel having a copper layer on the inner surface of the can and a nickel layer on the outer surface of the can. The negative electrode can 12 may include a surface having tin, an alloy thereof, or other agent on the inner surface in contact with the negative electrode 20. Tin can be on the inner surface of the negative electrode can 12 in contact with the negative electrode 20 and the electrolyte. Tin may be a continuous layer on the inner surface of the can. The tin layer may be a plating layer having a thickness of about 1-12 microns, such as about 2-7 microns, or about 4 microns. The tin may be pre-plated on the metal strip or post-plated on the negative electrode can 12. For example, tin can be deposited by immersion plating (eg, using a plating solution available from Technics, Rhode Island). The plating layer may have a glossy finish or a matte finish. The coating may also contain a silver compound or a gold compound.

  The positive electrode can 16 may include a cold rolled steel sheet having an inner layer and an outer layer of nickel. The insulator 24 (for example, an insulating gasket) is pressure-bonded between the negative electrode can 14 and the positive electrode can 16. The gasket can be thinned to increase battery capacity.

  The shape of the housing may have a vertical wall design, and the side wall of the negative electrode can 14 therein is a vertical or folded design. The folded design can be used for thin walled cans (eg, having a thickness of about 4 microns or less). In the folded design, the cut-out edge of the negative electrode can 14 (which occurs during the forging of the can) is placed at the top of the outside of the can, away from the inside of the battery. The folded design can reduce the generation of potential gases by reducing the possibility of contact between the exposed stainless steel and zinc at the cut edge of the negative electrode can. A vertical wall design can be used in conjunction with an L-type or J-type insulator, whereby the cut-out edge can be embedded in the bottom of the insulator. If a folded design is used, the insulator can be L-shaped.

  The overall battery height and diameter dimensions are defined by the International Electrotechnical Commission (IEC). For example, a button cell can have various dimensions: a 675 cell (IEC designation “PR44”) has a diameter of about 11.25 to 11.60 mm and a height of about 5.0 to 5.4 mm: 13 batteries (IEC designation “PR48”) have a diameter of about 7.55-7.9 mm and a height of about 5.0-5.4 mm: 312 batteries (IEC designation “PR41”) have a diameter of about 7.55 to 7.9 mm and height is about 3.3 to 3.6 mm: and 10 cells (IEC designation “PR70”) have a diameter of about 5.55 to 5.80 mm and a height of about 3 .30 to 3.60 mm. The AA battery has a diameter of about 5.55 to 5.80 mm and a height of about 2.03 to 2.16 mm. The battery 10 may have a negative electrode can having a thickness of about 0.1016 mm. The battery 10 can have a positive electrode can having a thickness of about 0.1016 mm.

  During storage, the air passage opening 18 can be protected with a removable sheet, sometimes known as a sealing tab, that is provided on the bottom surface of the positive electrode can 16 to cover the air passage opening. Thus, the air flow between the inside and the outside of the battery 10 is restricted. The user removes the sealing tab from the positive electrode can 16 and then activates and uses the battery. This allows oxygen from the air to enter the battery 10 from the outside environment.

  Other metal-air battery embodiments are also be used. Suitable examples are described, for example, in U.S. Patent No. 6,492,046 and U.S. Patent Application (U.S.S.N.) 09 / 773,962 (filed February 1, 2001) by the same applicant.

  The battery 10 can also be another type of battery, such as an air-assisted battery and an alkaline battery. Suitable examples of air assist batteries are described in US Pat. No. 6,372,370, US Pat. No. 6,399,243 and US Pat. No. 6,270,921. Alkaline batteries are disclosed in US Pat. No. 6,440,181 and commonly assigned US patent application (USSN) 09 / 829,709 (filed on April 10, 2001) and US patent application (USSN) 09/09. 658,042 (filed on Sep. 7, 2000).

  The battery 10 may be, for example, an AA battery, an AAA battery, an AAAA battery, an AA battery, a C battery, or a D battery. In other embodiments, the battery 10 can be non-cylindrical, such as a coin battery, a prismatic battery, or an oval battery.

  All references mentioned herein, such as patent applications, patent publications, and patents, are incorporated by reference in their entirety.

  Other embodiments are within the patent section.

Sectional drawing of an electrochemical cell.

Claims (35)

An electrochemical cell,
A housing;
A negative electrode in the housing;
An electrochemical cell comprising a positive electrode in a housing, the positive electrode comprising a catalyst and a wax, and a separator between the negative electrode and the positive electrode.   The battery according to claim 1, wherein the positive electrode has a first portion including a first wax concentration and a second portion including a second wax concentration lower than the first concentration.   The battery according to claim 2, wherein the second portion is between the first portion and the negative electrode.   The battery of claim 1, wherein the positive electrode has a first portion that includes wax and a second portion that is substantially free of wax.   The battery according to claim 4, wherein the second portion is between the first portion and the negative electrode.   The battery of claim 1, wherein the positive electrode has a first portion comprising wax, and the thickness of the first portion is less than about 0.1 mm.   The battery of claim 1, wherein the positive electrode has a first portion that includes wax, and the thickness of the first portion is less than about 20% of the thickness of the positive electrode.   The said positive electrode has a 1st part and the 2nd part arrange | positioned on the outer side with respect to the said 1st part, The wax concentration of the said 1st part is lower than the said 2nd part. battery.   The battery according to claim 1, wherein the positive electrode has an inner surface substantially free of wax.   2. The battery according to claim 1, wherein the positive electrode has a first layer containing wax and a second layer substantially free of wax, and the second layer is between the first layer and the negative electrode. .   The positive electrode includes a first layer having a first wax concentration and a second layer having a second concentration lower than the first wax concentration, and the second layer is between the first layer and the negative electrode. The battery according to claim 1.   The battery of claim 1, wherein wax is distributed substantially throughout the positive electrode.   The battery of claim 1, wherein the positive electrode comprises less than about 20% by weight wax.   The battery of claim 1, wherein the positive electrode comprises less than about 10% by weight wax.   The battery of claim 1, wherein the positive electrode comprises less than about 5% by weight wax.   The battery of claim 1, wherein the wax comprises a material selected from the group consisting of hexatriacontane, octacosan, carnauba wax, beeswax, cinnabar wax, and montan wax.   The battery of claim 1, wherein the positive electrode further comprises a binder.   The battery of claim 17, wherein the catalyst comprises manganese oxide and the binder comprises polytetrafluoroethylene.   The battery according to claim 1, wherein the battery is a metal-air battery.   The battery of claim 1, wherein the battery is an air-assisted battery.   The battery according to claim 1, wherein the battery is an alkaline battery. An electrochemical cell,
A housing defining an air passage opening;
A negative electrode in the housing, the negative electrode comprising zinc;
An electrochemical cell comprising a positive electrode in a housing, the positive electrode comprising manganese oxide and wax, and a separator between the negative electrode and the positive electrode.   The positive electrode has a first part containing manganese oxide and a wax, and a second part containing manganese oxide and substantially free of wax, the second part being between the first part and the negative electrode The battery according to claim 22.   The positive electrode has a first portion including manganese oxide and a first wax concentration, and a second portion including manganese oxide and a second wax concentration lower than the first concentration, and the second portion is the first portion. 23. The battery of claim 22, wherein the battery is between and a negative electrode.   23. The battery of claim 22, wherein the positive electrode comprises less than about 20% by weight wax.   23. The battery of claim 22, wherein the positive electrode comprises less than about 10% by weight wax.   23. The battery of claim 22, wherein the positive electrode comprises less than about 5% by weight wax.   23. The battery of claim 22, wherein the wax comprises a material selected from the group consisting of hexatriacontane, octacosan, carnauba wax, beeswax, cinnabar wax, and montan wax.   The battery according to claim 22, wherein the battery is a metal-air battery.   The battery of claim 22, wherein the battery is an air-assisted battery. A method of manufacturing an electrochemical cell comprising:
A manufacturing method comprising incorporating wax into a part of a positive electrode including a catalyst, and incorporating the positive electrode into the battery.   32. The method of claim 31, further comprising melting the wax.   32. The method of claim 31, further comprising applying a solid wax to the surface of the positive electrode.   32. The method of claim 31, further comprising contacting a substrate comprising wax with the positive electrode.   32. The method of claim 31, further comprising laminating the wax to the positive electrode.

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