Phosphate-based surfactant for alkaline battery anodes

Abstract

An anode composition, an alkaline battery, a method for producing a battery anode, and a method for producing a battery, wherein the anode comprises zinc or a zinc alloy and a surfactant of formula (I), wherein R1 is selected from aryl and C1-C12 alkyl, x is an integer from 2 to 30, n is an integer from 2 to 6, and y is 1 or 2.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 348,867, filed on June 3, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a phosphate - based surfactant for an alkaline battery anode, and an anode and a battery including the same.

Background Art

[0003] An electrochemical cell, or battery, is generally used as an electrical energy source. A battery typically contains a negative electrode, typically called an anode, and a positive electrode, typically called a cathode. The anode contains an electrochemically active anode material that can be oxidized. The cathode contains an electrochemically active cathode material that can be reduced. The electrochemically active anode material can reduce the electrochemically active cathode material. A separator is disposed between the anode and the cathode, and an ion - conductive electrolyte solution is in intimate contact with the cathode, the anode, and the separator. The battery components are typically disposed within a can or housing made of metal.

[0004] When a battery is used as an electrical energy source within an electronic device, electrical contact occurs to the anode and the cathode, electrons flow through the device, and respective oxidation and reduction reactions occur to enable power to be provided to the electronic device. The electrolyte contains ions that flow through the separator between the anode and the cathode to maintain charge balance throughout the battery during discharge.

[0005] There is an increasing need to fabricate batteries that are more suitable for powering modern electronic devices such as toys, remote controls, audio devices, flashlights, digital cameras and peripheral photographic equipment, electronic games, toothbrushes, radios, and watches. To meet this need, batteries can include a greater loading of electrochemically active anode and / or cathode materials to provide increased capacity and longevity. However, batteries also come in common size formats such as AA, AAA, AAAA, C, and D battery sizes and have fixed outer dimensions and a constrained internal volume. Thus, the ability to solely increase the loading of electrochemically active materials to achieve better performing batteries is limited.

[0006] The composition of the anode can be adjusted to provide performance improvements. For example, surfactants can be included in the anode composition to create a protective layer around zinc particles and inhibit the zinc corrosion reaction and hydrogen gas formation that can occur when the cell containing the anode is at rest. The surfactant adheres to the surface of the zinc anode particles and inhibits the approach of hydroxide ions or water to the zinc particles, thereby suppressing the corrosion of zinc and the formation of hydrogen gas (Reactions (I) and (II)) on the surface of the zinc particles. Zn + 4OH - → Zn(OH) 4 2- + 2e - (I) 2H 2 O + 2e - → 2OH - + H 2 (II) Phosphate ester surfactants, including polyoxyethylene dinonyl phenyl ether phosphate, are commonly used in battery anode compositions. However, this commonly used phosphate ester material contains a nonylphenol functional group that is regulated in some countries due to health and environmental concerns. Thus, surfactants that inhibit the zinc corrosion reaction and the accompanying hydrogen gas formation and do not contain a nonylphenol functional group are desirable. SUMMARY OF THE INVENTION

[0007] One aspect of the present disclosure provides an anode composition comprising zinc or a zinc alloy and a surfactant of formula (I),

Chemical formula

[0008] Another aspect of the present disclosure provides an anode composition comprising zinc or a zinc alloy and a surfactant of formula (II),

Chemical formula

[0009] Another aspect of the present disclosure provides an alkaline battery comprising an electrochemically active anode comprising zinc or a zinc alloy and a surfactant of formula (I),

Chemical formula

[0010] Yet another aspect of the present disclosure provides an alkaline battery comprising a zinc or zinc alloy and a surfactant of formula (II), the battery comprising an electrochemically active anode,

Chem.

[0011] An additional aspect of the present disclosure provides a method of making a battery anode comprising admixing a zinc or zinc alloy with a surfactant of formula (I),

Chem.

[0012] An additional aspect of the present disclosure provides a method of making a battery anode comprising admixing a zinc or zinc alloy with a surfactant of formula (II),

Chem.

[0013] Yet another aspect of the present disclosure provides a method of making a battery, comprising incorporating into the battery an anode comprising zinc or a zinc alloy and a surfactant of formula (I), [Chemical formula] wherein R1 comprises an aryl group, x is an integer from 2 to 30, n is an integer from 2 to 6, and y is 1 or 2. The aryl group of the surfactant can be selected from phenyl, naphthyl, fluorenyl, anthracenyl, phenanthryl, tetracenyl, benz[a]anthracenyl, pyrenyl, and perylenyl.

[0014] In a further aspect, the present disclosure provides a method of making a battery, comprising incorporating into the battery an anode comprising zinc or a zinc alloy and a surfactant of formula (II), [Chemical formula] wherein R is methyl or hydrogen, x is an integer from 2 to 30, and rings 1 and 2 represent a fused ring system containing at least 10 ring carbons. The fused ring system can be naphthyl, fluorenyl, anthracenyl, phenanthryl, tetracenyl, benz[a]anthracenyl, pyrenyl, perylenyl, biphenyl, or bicyclohexyl.

[0015] Further aspects and advantages will become apparent to those skilled in the art from a review of the following detailed description. The compositions and methods are susceptible to various modifications in different forms, but the following description includes specific embodiments with the understanding that the present disclosure is illustrative and not intended to limit the present disclosure to the specific embodiments described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as forming the invention. However, the invention will be better understood from the following description taken in conjunction with the accompanying drawings.

[0017]

Figure 1

Figure 2

Figure 3

DETAILED DESCRIPTION OF THE INVENTION

[0018] The present disclosure provides an anode composition, an alkaline battery, a method of making a battery anode, and a method of making a battery, wherein the anode comprises zinc or a zinc alloy and a surfactant of formula (I),

CHEM.

[0019] Another aspect of the present disclosure provides an anode composition comprising zinc or a zinc alloy and a surfactant of formula (II),

CHEM.

[0020] The anode of the present disclosure and a battery including the anode of the present disclosure advantageously provide one or more advantages, such as providing a zinc anode containing zinc particles, having a protective surfactant layer around the zinc particles that inhibits both the zinc corrosion reaction and the generation of hydrogen gas, and / or advantageously providing a battery having a good discharge capacity and not containing a nonylphenol functional group.

[0021] Referring to FIG. 1, a battery 10 according to the present invention includes a cathode 12, an anode 14, a separator 16, and a cylindrical housing 18. The battery 10 also includes a current collector 20, a seal 22, and a negative metal top cap 24, which serves as a negative terminal for the battery. The cathode 12 contacts the housing 18, and the positive terminal of the battery 10 is at the end of the battery opposite the negative terminal. An alkaline electrolyte is dispersed throughout the battery 10. The battery 10 can be, for example, an AA, AAA, AAAA, C, or D battery. The battery 10 can be cylindrical, although in some embodiments, the battery 10 can be non-cylindrical. For example, the battery 10 can be a coin cell, a button cell, or a wafer cell. In some embodiments, the battery can be prismatic. In some embodiments, the battery can have a rigid thin-layer cell configuration or be provided in a flexible pouch, envelope, or bag cell configuration. In some embodiments, the battery can have a helically wound jelly roll configuration or a flat plate configuration. Suitable batteries are described, for example, in U.S. Pat. Nos. 6,783,893, 7,435,395, and U.S. Patent Application Publication No. 2007 / 0248879.

[0022] Anode The anode 14 can be, for example, a zinc gel containing zinc metal particles, one or more gelling agents, one or more surfactants, and optionally a small amount of additives. In addition, a portion of the electrolyte solution is dispersed throughout the anode. The zinc metal particles can contain zinc (elemental metal). The zinc metal particles can be an alloy of zinc and further contain, for example, one or more metals selected from the group consisting of aluminum, bismuth, calcium, gallium, indium, lithium, magnesium, lead, and tin. The zinc metal particles can have a size in the range of 45 to 350 μm and a median particle size in the range of 80 to 255 μm when determined by CCD imaging measurement. To increase the surface area of zinc in the anode, zinc metal particles generally referred to as "fine particles" having a size of 44 microns or less can be included. The zinc fine particles can be included in an amount of about 1 wt% to about 30 wt%, about 5 wt% to about 30 wt%, about 10 wt% to about 25 wt%, for example, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, or about 30 wt% based on the total weight of the zinc metal particles.

[0023] The term "about" is used to mean, for example, approximately or around, according to its ordinary meaning. In one embodiment, the term "about" means ± 10% of the stated value or range of values. In another embodiment, the term "about" means ± 5% of the stated value or range of values. Values or ranges described in combination with the term "about" explicitly include the specific value and / or range as well (for example, for a value described as "about 40", "40" is also explicitly assumed). Further, the dimensions and values disclosed herein should not be understood to be strictly limited to the recited exact numerical values. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and the functionally equivalent range surrounding that value.

[0024] The amount of electrochemically active anode material within the anode can be referred to as the anode fill amount. The fill amount of the anode can vary depending on the electrochemically active anode material used within the battery and the cell size of the battery. For example, an AA battery having an electrochemically active zinc anode material can have an anode fill amount of at least about 3.3 grams of zinc metal particles, such as at least about 4.0, about 4.3, about 4.6 grams, about 5.0 grams, or about 5.5 grams of zinc metal particles. For example, an AAA battery having an electrochemically active zinc anode material can have an anode fill amount of at least about 1.9 grams of zinc metal particles, such as at least about 2.0 or about 2.1 grams of zinc metal particles. For example, an AAAA battery having an electrochemically active zinc anode material can have an anode fill amount of at least about 0.6 grams of zinc metal particles, such as at least about 0.7 to about 1.0 grams of zinc metal particles. For example, a C battery having an electrochemically active zinc anode material can have an anode fill amount of at least about 9.5 grams of zinc metal particles, such as at least about 10.0 to about 15.0 grams of zinc metal particles. For example, a D battery having an electrochemically active zinc anode material can have an anode fill amount of at least about 19.5 grams of zinc metal particles, such as at least about 20.0 to about 30.0 grams of zinc metal particles.

[0025] The anode typically includes a gelling agent. Examples of gelling agents include polyacrylic acid, polyacrylonitrile, starch, starch derivatives, grafted starch materials (such as starch-grafted polyacrylic acid, starch-grafted polyacrylonitrile), salts of polyacrylic acid, polyacrylates, cellulose derivatives, carboxymethyl cellulose, sodium carboxymethyl cellulose, polyacrylic acid crosslinked with a polyalkenyl ether of divinyl glycol, or combinations thereof. The anode can include, for example, from about 0.1 wt% to about 2 wt% of the gelling agent.

[0026] The surfactant of the present disclosure can include a surfactant according to formula (I),

Chemical formula

[0027] The surfactant of formula (I) is typically provided as a mixture of surfactants having formula (I). Generally, y can be selected from 1 or 2. Thus, in some embodiments, the surfactant contains a phosphoric acid monoester (i.e., when y is 1) or a phosphoric acid diester (i.e., when y is 2). In other embodiments, the phosphoric acid ester surfactant contains a mixture of a phosphoric acid monoester surfactant and a phosphoric acid diester surfactant according to formula (I). When y is 2, x and n appear twice and can vary independently, i.e., each x may be the same or different, and each n may likewise be the same or different.

[0028] In formula (I), x is in the range of 2 to 30, 3 to 25, 5 to 20, 8 to 20, 10 to 18, or 12 to 16, for example, any positive integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. In an embodiment, the surfactant of formula (I) comprises a mixture of surfactants of formula (I), and the mixture has an average x value in the range of 2 to 30, 3 to 25, 5 to 20, 8 to 20, 10 to 18, or 12 to 16, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. In an embodiment, the surfactant of formula (I) is provided as a mixture having an average x in the range of 6 to 16, 8 to 16, or 8 to 14. Without wishing to be bound by theory, it is believed that as the value of x (or the average value of x) decreases, the solubility of the surfactant in the electrolyte decreases. Further, without wishing to be bound by theory, as the value of x (or the average value of x) increases, the solubility of the surfactant increases, followed by an increase in chain association with other surfactant molecules and / or other materials, and / or the mass of the surfactant becomes too large, resulting in a final decrease. Advantageously, when x is in the range of 6 to 16, 8 to 16, or 8 to 14, advantageously while providing substantially the same performance, significantly less surfactant can be used compared to an anode containing a conventional polyoxyethylene dinonyl phenyl ether phosphate surfactant. Since less surfactant is included, a lower addition amount is used, and thus additional electrochemically active anode material can be included, leading to further performance enhancement compared to an anode containing a conventional polyoxyethylene dinonyl phenyl ether phosphate surfactant.

[0029] In formula (I), n can be any positive integer in the range of 2 to 6, for example, 2, 3, 4, 5, or 6. In an embodiment, n is in the range of 2 to 3. For example, n can be 2 or 3. Typically, n is 2. Without intending to be bound by theory, it is believed that as the value of n increases, the solubility of the surfactant in the electrolyte decreases.

[0030] The surfactant of the present disclosure may include a surfactant according to formula (II),

Chemical formula

[0031] The surfactant of formula (II) is typically provided as a mixture of surfactants having formula (I). In formula (II), x appears twice and can vary independently, that is, each x can be the same or different.

[0032] In formula (II), x is in the range of 2 to 30, 3 to 25, 5 to 20, 8 to 20, 10 to 18, or 12 to 16, for example, any positive integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. In an embodiment, the surfactant of formula (II) includes a mixture of surfactants of formula (II), and the mixture has an average x value in the range of 2 to 30, 3 to 25, 5 to 20, 8 to 20, 10 to 18, or 12 to 16, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. In an embodiment, the surfactant of formula (II) is provided as a mixture having an average x in the range of 6 to 16, 8 to 16, or 8 to 14. Without intending to be bound by theory, it is believed that as the value of x (or the average value of x) decreases, the solubility of the surfactant in the electrolyte decreases. Further, without intending to be bound by theory, as the value of x (or the average value of x) increases, the solubility of the surfactant increases, and subsequently, it is believed to ultimately decrease due to an increase in the association of chains with other surfactant molecules and / or other materials, and / or the mass of the surfactant becoming too large. Advantageously, when x is in the range of 12 to 16, advantageously, significantly less surfactant can be used compared to an anode containing a conventional polyoxyethylene dinonyl phenyl ether phosphate surfactant while providing substantially the same performance. Since less surfactant is included, a lower addition amount is used, and thus, additional electrochemically active anode material can be included, leading to further performance enhancement compared to an anode containing a conventional polyoxyethylene dinonyl phenyl ether phosphate surfactant. Additionally, by adding a lower volume of surfactant, beneficially, less destruction of the pregel anode occurs, and thus, an anode with a higher yield stress can be obtained.

[0033] The surfactant according to formula (I) and / or (II) is included in the anode composition to create a protective layer around the zinc particles and inhibit the zinc corrosion reaction, but must be dissociable from the surface of the zinc particles to allow the discharge reaction to proceed. The surfactant according to formula (I) and / or (II) is in the range of about 10 ppm to about 75 ppm, about 10 ppm to about 65 ppm, about 10 ppm to about 55 ppm, about 10 ppm to about 50 ppm, about 20 ppm to about 50 ppm, or about 20 ppm to about 45 ppm, for example, with respect to the amount of zinc in the anode composition, and can be included in the anode composition in an amount of about 10 ppm, about 15 ppm, about 20 ppm, about 25 ppm, about 30 ppm, about 35 ppm, about 40 ppm, about 45 ppm, or about 50 ppm, with respect to the amount of zinc metal particles in the anode composition. The amount of the surfactant according to formula (I) and / or (II) is provided in units of parts per million with respect to the amount of zinc metal particles. Thus, for every 1 million parts by weight of zinc metal particles, there are, for example, 10 - 75 parts by weight of the surfactant according to formula (I) and / or (II). The surfactant according to formula (I) and / or (II) can be diluted to 1% in a 0.05 M alkali hydroxide, for example, a KOH solution, to enable more accurate addition to the anode composition. Without intending to be bound by theory, it is believed that as the level of the surfactant increases with respect to the amount of zinc metal particles in the anode, the surface passivation of the zinc anode increases. Thus, more energy is required to remove the surfactant molecules from the surface of the zinc metal particles to allow the discharge reaction to proceed. Without intending to be bound by theory, the increased surface passivation can be attributed to the surfactant monolayer on the surface of the anode being too thick, the formation of multilayer surfactant micelles on the surface of the anode, or a combination thereof. Advantageously, as shown in the examples provided below, the surfactant according to formula (I) and / or (II) provides a suitable surface coating for the zinc anode using less surfactant than typical commercially available surfactants, thereby reducing the energy required to remove the surfactant from the anode surface and allow the discharge reaction to proceed.Of course, surfactants can also be used at higher levels, similarly.

[0034] Advantageously, the surfactants according to formulas (I) and (II) do not contain nonylphenol functional groups. As used herein, "does not contain nonylphenol functional groups" means that the surfactant does not contain nonylphenol functional groups and / or the anode composition containing the surfactant does not contain a substantial amount of surfactant having nonylphenol functional groups. Thus, an incidental or background amount of surfactant having nonylphenol functional groups (e.g., less than about 100 ppb) may be present in the surfactant and / or anode composition and be within the scope of the present disclosure.

[0035] Additionally, the surfactant coverage rate of zinc particles by the surfactant may affect the performance degradation of the battery containing it. Without intending to be bound by theory, if the surfactant can reach the maximum surface coverage of the zinc metal particles of the anode more quickly, the time for the zinc metal particles to be directly exposed to the electrolyte is minimized, so it is considered that the battery containing the anode shows less performance capacity degradation. The performance capacity of the battery can be measured using various known techniques, including but not limited to those described below.

[0036] Electrolyte The electrolyte can be dispersed throughout the cathode, anode, and separator. The electrolyte contains an ion-conductive component in an aqueous solution. The ion-conductive component can be a hydroxide. The hydroxide can be, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, or a mixture thereof. The ion-conductive component can also further contain a salt. The salt can be, for example, zinc chloride, ammonium chloride, magnesium perchlorate, magnesium bromide, and mixtures thereof. The concentration of the ion-conductive component can be selected depending on the battery design and its desired performance. An aqueous alkaline electrolyte can contain a hydroxide as the ion-conductive component in a solution having water. The concentration of the hydroxide in the electrolyte can be about 25 weight percent (wt%) to about 35 wt% based on the total weight of the electrolyte. For example, the hydroxide concentration of the electrolyte can be about 25 wt% to about 33 wt%, or about 25 wt% to about 32 wt% based on the total weight of the electrolyte.

[0037] Regarding an assembled alkaline cell, the concentration of the ion-conductive component can be determined by collecting the total amount of electrolyte from within the assembled alkaline cell, such as an AA or AAA alkaline cell. This can generally be achieved by removing the separator, cathode, and anode components and dissolving these components in a hydrochloric acid solution. Hydrogen peroxide can be added in a dropwise manner to assist the dissolution process. The dissolved solution can then be diluted to a specific volume to provide an analyte. The analyte can then be analyzed via an inductively coupled plasma (ICP) optical spectrometer, such as JY Ultratrace or its equivalent, to determine the total cation concentration of the ion-conductive component within the analyte, such as the potassium (K+) concentration in ppm units. The total cation concentration determined via ICP from the analyte can be used to mathematically determine the total weight of the cations, such as potassium (K+) in grams, within the electrolyte solution of the sampled alkaline cell, and subsequently, the total weight of the ion-conductive component, such as potassium hydroxide (KOH) in grams. The concentration of the ion-conductive component of the electrolyte on a weight basis of the electrolyte, such as potassium hydroxide (KOH), can be determined by dividing the total weight of the ion-conductive component by the analyte weight.

[0038] The aqueous alkaline electrolyte may also contain zinc oxide (ZnO). ZnO can serve to suppress zinc corrosion within the anode. The concentration of ZnO contained within the electrolyte can be less than about 3 weight % of the electrolyte. The ZnO concentration can be, for example, less than about 2 weight % of the electrolyte.

[0039] In an embodiment, the total weight of the aqueous alkaline electrolyte in an AA alkaline battery can be, for example, from about 3.0 grams to about 4.0 grams, for example, from about 3.3 grams to about 3.8 grams, or from about 3.4 grams to about 3.6 grams. In an embodiment, the total weight of the aqueous alkaline electrolyte in an AAA alkaline battery can be, for example, from about 1.0 gram to about 2.0 grams, for example, from about 1.2 grams to about 1.8 grams, or from about 1.4 grams to about 1.6 grams. While the foregoing amounts are intended to be useful, one of ordinary skill in the art can readily determine the appropriate weight of the aqueous alkaline electrolyte required for other battery sizes, types, and configurations.

[0040] Cathode Cathode 12 can include an electrochemically active cathode material, carbon particles, and optionally, a binder. The electrolyte solution is also dispersed through cathode 12. The weight percentages provided above and below are determined after the electrolyte solution has been dispersed.

[0041] The electrochemically active cathode material may include one or more manganese oxides. For example, the electrochemically active cathode material may include one or more manganese dioxides selected from the group consisting of electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high-power electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, gamma manganese dioxide, and beta manganese dioxide. Other suitable electrochemically active cathode materials may be used, including, but not limited to, silver oxide, nickel oxide, silver nickel oxide, nickel oxyhydroxide, copper oxide, silver copper oxide, bismuth oxide, high-valent nickel, their alloys, and their mixtures. Nickel oxide may include nickel hydroxide, nickel oxyhydroxide, nickel oxyhydroxide coated with cobalt oxyhydroxide, delithiated layered lithium nickel oxide, partially delithiated layered lithium nickel oxide, and combinations thereof. Nickel oxyhydroxide may include beta-nickel oxyhydroxide, gamma-nickel oxyhydroxide, twins of beta-nickel oxyhydroxide, gamma-nickel oxyhydroxide, nickel oxyhydroxide coated with cobalt oxyhydroxide, and mixtures thereof. Nickel oxyhydroxide coated with cobalt oxyhydroxide may include beta-nickel oxyhydroxide coated with cobalt oxyhydroxide, gamma-nickel oxyhydroxide coated with cobalt oxyhydroxide, twins of beta-nickel oxyhydroxide and gamma-nickel oxyhydroxide coated with cobalt oxyhydroxide, and mixtures thereof. Nickel oxide may include partially delithiated layered nickel oxide having the general chemical formula Li 1-x H y NiO 2 where 0.1 < x < 0.9 and 0.1 < y < 0.9. Nickel oxide may have the general chemical formula A x H y Ni 1+a-z M zIt may contain a partially delithiated layered nickel oxide having O2, wherein A contains an alkali metal, 0.08 ≦ x < 0.2, 0 ≦ y < 0.3, 0.02 ≦ a ≦ 0.2, M contains a transition metal or a typical metal, and 0 ≦ z ≦ 0.2. The high-valence nickel is, for example, a compound containing tetravalent nickel as disclosed in US-2018-0331361-A1 (incorporated herein by reference), for example, a compound of the general formula A x A’ v Ni 1+a-z M z O 2 ·nH 2 O, and may be a compound having the formula, wherein A contains an alkali metal, A’ contains an alkali metal different from A, M contains a transition metal or a non-transition metal, 0.04 ≦ x < 0.2, 0.03 ≦ v < 0.2, 0.02 ≦ a ≦ 0.2, 0 ≦ z < 0.2, and 0 < n < 2.

[0042] EMD is typically produced from the direct electrolysis of a bath of manganese sulfate and sulfuric acid. The process for the production of EMD and its properties are described in Batteries, edited by Karl V. Kordesch, Marcel Dekker, Inc., New York, Vol. 1, (1974), p. 433-488. CMD is typically produced by a process known in the art as the "Sedema process", a chemical process disclosed by U.S. Patent No. 2,956,860 (Welsh). Battery-grade MnO 2 is, via the Sedema process, MnSO 4 and an alkali metal chlorate, for example, NaClO 3It can be produced by using a reaction mixture with. Suitable manganese dioxide can be obtained, for example, from Tronox (Stamford, CT), Vibrantz Technologies (Houston, TX), Tosoh Corportation (Tokyo, Japan), Delta Manganese Ltd. (Mbombela, South Africa), and Xiangtan Electrochemical Scientific (Xiangtan, China).

[0043] Conventional battery-grade manganese dioxide-containing compositions do not have the true stoichiometric formula MnO 2 but are better represented by the formula MnO x wherein x is typically about 1.92 to 1.96 and corresponds to a manganese valence of about 3.84 to 3.92. Conventional EMD can typically have a value for x of about 1.95 or 1.96, corresponding to manganese valences of 3.90 and 3.92, respectively. Conventional EMD also has a true density of about 4.4 g / cm 3 ~4.6 g / cm 3 .

[0044] The carbon particles can be any of the conventional carbon particles used in the cathode. The carbon particles can be, for example, graphite particles. The graphite can be synthetic or non-synthetic, or a blend of synthetic and non-synthetic. Suitable graphite particles can be obtained, for example, from Nacional de Grafite (Sao Paulo, Brazil), Imerys Graphite & Carbon (Bodio, Switzerland), and Superior Graphite Company (Chicago, Illinois). The cathode can contain, for example, from about 3 wt% to about 7 wt%, such as from about 4 wt% to about 6.5 wt% or from about 2 wt% to about 5 wt% of carbon particles.

[0045] Carbon particles are included in the cathode to conduct electrons through the cathode. Lower levels of carbon particles allow for the inclusion of higher levels of active material within the cathode without increasing the cell volume or reducing the void volume (which must be maintained above a certain level to prevent the internal pressure from becoming too high due to gas generation within the cell).

[0046] The binder is stable in the presence of the electrochemically active cathode material. The binder typically has minimal swelling behavior in water. By minimizing the amount of swelling of the binder, the amount of electrochemically active cathode material in the cathode is maximized. In embodiments, the binder has a swelling of about 10% or less, about 5% or less, or about 3% or less in water. Examples of suitable binders include hydroxypropyl methylcellulose (HPMC), polyacrylate, polyvinyl alcohol (PVOH), polyethylene powder, polyacrylamide, Portland cement, and fluororesins such as PVDF and PTFE. An example of a polyethylene binder is sold under the trade name Coathylene HA-1681 (available from Axalta Coating Systems, PA). The cathode can include, for example, from about 0.1 wt% to about 1 wt% of the binder. Lower binder levels allow for the inclusion of higher levels of active material within the cathode.

[0047] Cathode 12 can include other additives. Examples of other cathode additives are described, for example, in U.S. Patent Nos. 5,342,712, 5,698,315, 5,919,598, 5,997,775, and 7,351,499, which are incorporated herein by reference. Cathode 12 can include, for example, from about 0.2 wt% to about 2 wt% of TiO2. The cathode can also include a surfactant. The surfactant needs to be compatible with the binder so as not to adversely affect the binding ability. Examples of surfactants suitable for the cathode include, but are not limited to, anionic surfactants, amphoteric surfactants, and combinations thereof.

[0048] One non-limiting example of a surfactant suitable for the cathode may include diphenylsulfonate or a derivative thereof. In one embodiment, the surfactant includes an anionic diphenylsulfonate surfactant or a hydrocarbyl-substituted derivative thereof, and the hydrocarbyl group contains from 1 to about 24, for example, from 1 to about 12 carbon atoms. Specific examples include alkali metal alkyldiphenyloxide disulfonates such as sodium hexyl diphenyloxide disulfonate, sodium decyl diphenyloxide disulfonate, dodecyl diphenyloxide disulfonic acid, sodium dodecyl diphenyloxide disulfonate, N-decyl diphenyloxide disulfonate, sodium n-decyl diphenyloxide disulfonate, and sodium n-hexadecyl diphenyloxide disulfonate. The diphenlyoxide sulfonate surfactant is commercially available under the trade name DOWFAX™ (The Dow Chemical Company, MI), and specifically includes DOWFAX™ C6L, C10L, 2AO, 2A1, 2A1-D, 2EP, 3BO, 3B2, 3B2-D, 2000, 8390, and 8390-D.

[0049] The amount of electrochemically active cathode material in the cathode can be referred to as the cathode fill amount. The fill amount of the cathode can vary depending on the electrochemically active cathode material used in the battery and the cell size of the battery. For example, an AA battery having a manganese dioxide electrochemically active cathode material can have a cathode fill amount of at least 10.0 grams of manganese dioxide, for example, at least about 10.5 grams of manganese dioxide, about 10.7 grams to about 11.5 grams of manganese dioxide, about 10.7 grams to about 11.0 grams of manganese dioxide, about 10.8 grams to about 11.2 grams of manganese dioxide, about 10.9 grams to about 11.5 grams of manganese dioxide. For an AAA battery, the cathode fill amount can be about 4.0 grams to about 6.0 grams of manganese dioxide. For an AAAA battery, the cathode fill amount can be about 2.0 grams to about 3.0 grams of manganese dioxide. For a C battery, the cathode fill amount can be about 25.0 grams to about 29.0 grams of manganese dioxide. For a D battery, the cathode fill amount can be about 54.0 grams to about 70.0 grams of manganese dioxide.

[0050] The cathode has a dry density sufficient to allow for good conductivity. The cathode dry density can be about 2.0 g / cm 2 ~3.5 g / cm 2 or about 2.4 g / cm 2 ~3.3 g / cm 2 and can be.

[0051] Separator Separator 16 may have any of the conventional designs for battery separators. In some embodiments, the separator may include woven or non-woven paper or cloth. The separator may include, for example, a layer of cellophane combined with a layer of non-woven material. The cellophane layer may be adjacent to cathode 12 or anode 14. The separator may also include additional layers of non-woven material. The separator active material may be thin. The separator may have, for example, a dry thickness of less than 150 micrometers (microns). The separator may have, for example, a dry thickness of less than 100 microns, such as from about 70 microns to about 90 microns, or from about 70 microns to about 75 microns. The separator has a basis weight of 40 g / m 2 Hereinafter, for example, about 15 g / m 2 to about 40 g / m 2 or about 20 g / m 2 to about 30 g / m 2 and has a basis weight of about 15 g / m to about 40 g / m, or about 20 g / m to about 30 g / m.

[0052] Battery housing 18 can be any conventional housing commonly used for primary alkaline batteries. The battery housing can be made from a metal, such as nickel-plated cold-rolled steel. The housing generally includes an inner electrically conductive metal wall and an outer electrically non-conductive material such as a heat-shrinkable plastic. An additional layer of conductive material can be disposed between the inner wall of battery housing 18 and cathode 12. This layer can be disposed along the inner surface of the wall, around cathode 12, or both. This conductive layer can be applied to the inner wall of the battery as a paint or dispersion containing, for example, a carbonaceous material, a polymer binder, and one or more solvents. The carbonaceous material can be carbon particles, such as carbon black, partially graphitized carbon black, or graphite particles.

[0053] Anode current collector 20 passes through a seal 22 that extends into anode 14. Current collector 20 is made from a suitable metal such as brass or brass-plated steel. The upper end of current collector 20 is in electrical contact with negative upper cap 24. Seal 22 can be made from a thermoplastic material such as nylon.

[0054] The battery 10 can be assembled using conventional methods and sealed by a mechanical crimping process.

[0055] The compositions and methods according to the present disclosure can be better understood in view of the following examples, which are intended merely to illustrate the compositions and methods of the present disclosure and are not meant to limit its scope in any way.

[0056] Performance Test Method The performance test includes a discharge performance test that can be referred to as the ANSI / IEC motor / toy test. The toy test protocol includes applying a constant load of 3.9 ohms for 1 hour, resting the battery for a predetermined period, and then applying the load again. This cycle is repeated until a cut-off voltage of 0.8 volts is reached. The results are reported in terms of the actual run time (or the time the load is applied). In the modified protocol results shown in Example 2, the battery is rested for 12 hours. Typically, as implemented in Example 3, a 23-hour rest is used, but the results are typically the same with shorter rest periods. The Maccor test system was used.

[0057] The performance tests also include a discharge performance test that can be referred to as the Digital Camera (DigiCam) test. The Digital Camera test is a pulse test protocol that involves discharging the battery with high-power and medium-power pulse discharge cycles. Each discharge cycle consists of a combination of two discharge regimes: a 1.5-watt high-power pulse for 2 seconds, followed immediately by a 650 mW medium-power pulse for 28 seconds. This combination of discharge regimes is repeated 10 times (i.e., for a total of 5 minutes), and then the battery is rested for 55 minutes. The combination of high-power and medium-power discharge pulses and rest periods (i.e., 1 hour / cycle) is repeated until a cut-off voltage of 1.05 volts is reached. The number of cycles required to reach the cut-off voltage is reported as "pulses" or "images". The reported number of pulses consists of the total number of 1.5-watt high-output pulses corresponding to the total number of discharge cycles. The Digicam discharge test is considered to be a high-rate intermittent discharge test for conventional AA batteries. The Maccor test system was used.

[0058] The performance tests also include a discharge performance test that can be referred to as the 3.9-ohm continuous discharge test. The 3.9-ohm continuous discharge test protocol involves discharging the battery to support a constant load of 3.9 ohms until a cut-off voltage of 0.8 volts is reached. The results are reported in actual operating time (or the time the load is applied). The Maccor test system was used.

[0059] The performance tests further include a discharge performance test that can be referred to as the pulse load voltage test. The pulse load voltage test protocol involves discharging the battery for 1 second at a current drain of 80 mA and then measuring the voltage immediately afterwards. The Maccor test system was used.

[0060] The performance tests include a discharge performance test that can be referred to as the intermittent 3.9-ohm discharge test. The cell was discharged at 3.9 ohms for 1 hour on a Maccor test device, rested for 12 hours, and then repeated again for the indicated number of pulses. The discharge curve shows voltage vs. capacity and indicates the relative difference in capacity (or discharge rate) between cells. The Maccor test system was used.

Example

[0061] Example 1 Ethoxylated naphthol phosphate was synthesized by reacting ethoxylated naphthol (Angene International Limited, Nanjing, China) and phosphorus pentoxide (P2O5) at a ratio of 12:1 and stirring in a beaker on a hot plate inside an argon glove box. Different ethoxylated aromatic species can be easily synthesized using known ethoxylation procedures and can be reacted with phosphorus pentoxide as well.

[0062] A slightly alkaline orange viscous product solution of 3% was prepared for addition to the zinc anode. Advantageously, the material showed higher water solubility than polyoxyethylene dinonyl phenyl ether phosphate typically used in anode compositions.

[0063] The surfactant was analyzed and characterized by 1H and 31P NMR. The degree of ethoxylation was determined by setting the integration standard in the aromatic region of the 1H NMR spectrum and dividing the total in the region of 3.2 - 4.2 ppm by 4. The degree of ethoxylation was determined to be 14. The mol% of each phosphorus species was determined by integrating the peak areas of 31P NMR collected using inverse gated decoupling. The 31P NMR analysis showed that the surfactant contains 75 mol% of phosphoric acid monoester, 18 mol% of phosphoric acid diester, and 7% of residual phosphoric acid.

[0064] Example 2 AA batteries having the same components were prepared except for the surfactant composition of the anode. The surfactant concentration in the anode composition is reported relative to the weight of zinc metal particles. The anode compositions were made at different concentrations using the surfactant synthesized in Example 1, and the assembled batteries were compared with comparative battery examples containing an anode composition containing polyoxyethylene dinonyl phenyl ether phosphate, a surfactant conventionally used in the anode composition of commercially available batteries, as described above. The batteries were stored at room temperature and then tested for performance as described above. One cell was tested per group. The results are shown in Table 1 below.

Table 1

[0065] Example 2 shows that, compared with Comparative Example D, battery Examples A, B, and C according to the present invention show equivalent results for Digicam, Fast Toy, and continuous discharge, and that the amount of zinc surface coating provided by the surfactant of the present disclosure is equivalent to the surface coating provided by a commercially available comparative surfactant, despite including a remarkably and surprisingly low surfactant concentration. These results surprisingly show similar battery performance at a level close to 20% of the amount of surfactant used in the comparative example. Thus, Example 2 shows that the batteries of the present disclosure containing an anode containing the surfactant according to the present disclosure contain significantly less surfactant than the comparative batteries and perform at least as well as the comparative batteries, despite not containing a nonylphenol functional group.

[0066] The surfactant of the present disclosure can advantageously coat the surface of the anode using substantially less surfactant than required by commercially available surfactants, so there is less surfactant on the surface of the anode that must be removed to allow the discharge reaction to proceed. Without intending to be bound by theory, the surfactant of the present disclosure is thought to have higher solubility in alkaline electrolytes than commercially available surfactants. As a result, advantageously, less energy is required to remove the surfactant of the present disclosure from the anode surface.

[0067] Example 3 AA batteries having the same components were prepared except for the surfactant composition of the anode. The surfactant concentration in the anode composition is reported relative to the weight of the zinc metal particles. One anode composition was made using the surfactant synthesized in Example 1, and the assembled battery was compared, as described above, to a comparative battery example containing an anode composition containing polyoxyethylene dinonyl phenyl ether phosphate, a surfactant conventionally used in the anode composition of commercially available batteries. The batteries were stored at room temperature and then tested for performance as described above. Two cells were tested for each group and the averages are reported below. The results are shown in Table 2 below.

Table 2

[0068] Example 3 shows that, compared to Comparative Battery Example F, Battery Example E exhibits equivalent results for Digicam, Fast Toy, and pulse load voltage, and that the amount of zinc surface coating provided by the surfactant of the present disclosure is incorporated at a significantly and surprisingly low surfactant concentration, yet is equivalent to the surface coating provided by a commercially available comparative surfactant. Similar to the results shown in Example 2, these results surprisingly show similar battery performance at a level close to 20% of the amount of surfactant used in the corresponding comparative example. Thus, Example 3 further supports that the battery of the present disclosure containing an anode comprising a surfactant according to the present disclosure performs at least as well as the comparative battery, despite containing significantly less surfactant.

[0069] Example 4 AA batteries having the same components except for the surfactant composition of the anode were prepared. In this example, a battery containing an anode composition comprising a surfactant according to the present invention is compared with a battery containing an anode without a surfactant.

[0070] Figure 2 shows the continuous discharge at 3.9 ohms for an AA cell containing an anode without a surfactant additive compared to an AA cell containing an anode comprising a surfactant according to the present invention, specifically an ethoxylated naphthol phosphate prepared according to Example 1. Figure 2 shows that the AA cell containing an anode without a surfactant additive underwent earlier polarization compared to the AA cell containing an anode comprising a surfactant according to the present invention.

[0071] Figure 3 shows the intermittent discharge at 3.9 ohms for an AA cell containing an anode without an additive compared to an AA cell containing an anode comprising a surfactant according to the present invention, specifically an ethoxylated naphthol phosphate prepared according to Example 1. Figure 3 shows that the AA cell containing an anode comprising a surfactant according to the present invention exhibited a greater capacity compared to the AA cell containing an anode without a surfactant additive.

[0072] The foregoing description is given for clarity of understanding only, and it should be understood therefrom that modifications within the scope of the present disclosure may be apparent to those skilled in the art and that there is no unnecessary limitation.

[0073] All patents, publications, and references cited herein are hereby incorporated by reference in their entirety into this specification. In the event of any conflict between this disclosure and the incorporated patents, publications, and references, this disclosure shall prevail.

Claims

1. An anode composition comprising: zinc or a zinc alloy; and a surfactant of formula (I), wherein: 【Chemical 1】 R1 comprises an aryl group; y is 1 or 2; x is an integer from 2 to 30; and n is an integer from 2 to 6.

2. The anode composition according to claim 1, wherein R1 comprises one or more aryl groups selected from naphthyl, fluorenyl, anthracenyl, phenanthryl, tetracenyl, benz[a]anthracenyl, pyrenyl, and perylenyl.

3. The anode composition according to claim 1 or 2, wherein n is an integer from 2 to 3.

4. The anode composition according to any one of the preceding claims, wherein n is 2.

5. The anode composition according to claim 1 or 2, wherein n is 3.

6. The anode composition according to any one of the preceding claims, wherein the surfactant of formula (I) comprises a mixture of surfactants of formula (I).

7. The anode composition according to any one of the preceding claims, wherein the surfactant of formula (I) comprises a mixture of a phosphoric acid monoester surfactant and a phosphoric acid diester surfactant according to formula (I).

8. The anode composition according to any one of the preceding claims, which does not contain a nonylphenol functional group.

9. The anode composition according to claim 6 or 7, wherein for the mixture of surfactants of formula (I), the average x is an integer from 6 to 16, from 8 to 16, or from 8 to 14.

10. The anode composition according to any one of the preceding claims, wherein R1 is 2-naphthyl.

11. The anode composition according to any one of the preceding claims, wherein the surfactant according to formula (I) is provided in an amount of about 10 ppm to about 75 ppm, about 10 ppm to about 65 ppm, about 10 ppm to about 55 ppm, about 10 ppm to about 50 ppm, about 20 ppm to about 50 ppm, or about 20 ppm to about 45 ppm based on the amount of zinc or zinc alloy.

12. An alkaline battery comprising: an anode comprising the anode composition according to any one of claims 1 to 11; a cathode; a separator between the anode and the cathode; and an alkaline electrolyte.

13. The battery according to claim 12, wherein the alkaline electrolyte comprises hydroxide in an amount of about 25 weight percent (wt%) to about 40 wt% based on the weight of the electrolyte in the battery.

14. The battery according to claim 12 or 13, wherein the cathode comprises one or more manganese dioxides selected from the group consisting of one or more of manganese dioxide, such as electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high-power electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, gamma manganese dioxide, and beta manganese dioxide.

15. The battery according to any one of claims 12 to 14, wherein the cathode comprises one or more electrochemically active cathode materials selected from the group consisting of silver oxide, nickel oxide, silver nickel oxide, nickel oxyhydroxide, copper oxide, silver copper oxide, bismuth oxide, higher-valent nickel, and alloys thereof.

16. The battery according to claim 15, wherein the cathode comprises one or more nickel oxides selected from the group consisting of nickel hydroxide, nickel oxyhydroxide, nickel oxyhydroxide coated with cobalt oxyhydroxide, delithiated layered lithium nickel oxide, partially delithiated layered lithium nickel oxide, and combinations thereof.

17. A method of making a battery anode, comprising mixing zinc or a zinc alloy with a surfactant of formula (I), 【Chemical 2】 wherein R1 is selected from aryl, y is 1 or 2, x is an integer from 2 to 30, n is an integer from 2 to 6.

18. A method of making a battery, comprising incorporating into the battery an anode comprising zinc or a zinc alloy and a surfactant of formula (I), 【Chemical Formula 3】 wherein R1 is selected from aryl and C1-C12 alkyl, y is 1 or 2, x is an integer from 2 to 30, n is an integer from 2 to 6.

19. The method according to claim 18, wherein the surfactant according to formula (I) is provided in an amount in the range of about 10 ppm to about 75 ppm, about 10 ppm to about 65 ppm, about 10 ppm to about 55 ppm, about 10 ppm to about 50 ppm, about 20 ppm to about 50 ppm, or about 20 ppm to about 45 ppm relative to the amount of zinc or zinc alloy in the anode composition.

20. An anode composition comprising zinc or a zinc alloy, and a surfactant of formula (I), [Chemical Formula 4] wherein R is methyl or hydrogen, x is an integer from 2 to 30, rings 1 and 2 represent a fused ring system containing at least 10 ring carbons.

21. The anode composition according to claim 20, wherein the linking ring system includes naphthyl, fluorenyl, anthracenyl, phenanthryl, tetracenyl, benz[a]anthracenyl, pyrenyl, perylenyl, biphenyl, or bicyclohexyl.

22. The anode composition according to claim 20 or 21, wherein n is an integer from 2 to 3.

23. The anode composition according to any one of claims 20 to 22, wherein n is 2.

24. The anode composition according to any one of claims 20 to 22, wherein n is 3.

25. The anode composition according to any one of claims 20 to 24, wherein the surfactant of formula (II) includes a mixture of surfactants of formula (II).

26. The anode composition according to any one of claims 20 to 25, wherein the anode composition does not contain a nonylphenol functional group.

27. The anode composition according to claim 25, wherein for the mixture of surfactants of formula (II), the average x is an integer from 6 to 16, 8 to 16, or 8 to 14.

28. The anode composition according to any one of claims 20 to 27, wherein R1 is 2-naphthyl.

29. The anode composition according to any one of claims 20 to 28, wherein the surfactant according to formula (I) is provided in an amount of about 10 ppm to about 75 ppm, about 10 ppm to about 65 ppm, about 10 ppm to about 55 ppm, about 10 ppm to about 50 ppm, about 20 ppm to about 50 ppm, or about 20 ppm to about 45 ppm with respect to the amount of zinc or zinc alloy.

30. An alkaline battery, comprising: an anode including the anode composition according to any one of claims 20 to 29; a cathode; a separator between the anode and the cathode; and an alkaline electrolyte.

31. The battery according to claim 30, wherein the alkaline electrolyte contains hydroxide in an amount of about 25 weight percent (wt%) to about 40 wt% based on the weight of the electrolyte in the battery.

32. The battery according to claim 30 or 31, wherein the cathode includes one or more manganese dioxides selected from one or more within the group of one or more manganese oxides such as electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high-power electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, gamma manganese dioxide, and beta manganese dioxide.

33. The battery according to any one of claims 30 to 32, wherein the cathode comprises one or more electrochemically active cathode materials selected from the group consisting of silver oxide, nickel oxide, silver nickel oxide, nickel oxyhydroxide, copper oxide, silver copper oxide, bismuth oxide, high-valent nickel, and alloys thereof.

34. The battery according to claim 33, wherein the cathode comprises one or more nickel oxides selected from the group consisting of nickel hydroxide, nickel oxyhydroxide, nickel oxyhydroxide coated with cobalt oxyhydroxide, delithiated layered lithium nickel oxide, partially delithiated layered lithium nickel oxide, and combinations thereof.

35. A method of fabricating a battery anode, comprising admixing zinc or a zinc alloy with a surfactant of formula (I), [Chemical Formula 5] wherein R is methyl or hydrogen, x is an integer from 2 to 30, and rings 1 and 2 represent a fused ring system containing at least 10 ring carbons.

36. A method of fabricating a battery, comprising incorporating into the battery an anode comprising zinc or a zinc alloy and a surfactant of formula (II), 【Chemical Formula 6】 wherein R is methyl or hydrogen, x is an integer from 2 to 30, and rings 1 and 2 represent a fused ring system containing at least 10 ring carbons.

37. The method according to claim 36, wherein the surfactant according to formula (I) is provided in an amount in the range of about 10 ppm to about 75 ppm, about 10 ppm to about 65 ppm, about 10 ppm to about 55 ppm, about 10 ppm to about 50 ppm, about 20 ppm to about 50 ppm, or about 20 ppm to about 45 ppm relative to the amount of zinc or zinc alloy in the anode composition.

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