Bipolar battery comprising a separator based on a proton and hydroxide ion conductive polymer

Abstract

To provide new designs and materials for efficient and compact bipolar batteries. A bipolar battery is provided that includes a plurality of stacked cells. Two or more of the cells include a positive electrode, a negative electrode, a proton or hydroxide ion conducting polymer separator between the positive electrode and the negative electrode, and a bipolar metal plate associated with the negative electrode or the positive electrode. In some embodiments, the separator includes a proton or hydroxide conducting electrolyte or functions solely as a proton or hydroxide conducting electrolyte. The cells optionally include an electrolyte that includes a polymer capable of conducting protons or hydroxide ions. The separator may be in the form of a film, optionally not attached to either the negative electrode or the positive electrode, or may be in the form of a coating on the negative electrode, the positive electrode, or any combination thereof.

Description

Technical Field

[0001] The present disclosure relates to batteries, and more particularly to secondary batteries that circulate protons or hydroxide ions between a negative electrode and a positive electrode in the generation of an electric current that can be used to power one or more devices.

Background Art

[0002] In the field of energy storage, there is a general demand for improving power density. As the requirements for size, weight, and the ability to supply large amounts of energy when needed continue to increase, new battery designs are needed. Bipolar batteries have advantages that help meet these needs compared to other battery designs. Bipolar batteries have improved scalability, relatively high energy density, high power density, and design freedom.

[0003] A bipolar battery generally features a bipolar plate formed of a substrate having a positive electrode material on one surface and a negative electrode material on the opposite side. To enable the formation of individual cells that can be effectively used for energy storage or generation, the bipolar plates can be stacked such that the negative electrode material is effectively combined with the positive electrode material on another bipolar plate, with a separator and an electrolyte present between the two. The electrolyte and the separator allow for ion flow between the negative electrode material and the positive electrode material. In a bipolar battery, the electrolytes of the individual cells are insulated from each other to prevent short-circuiting of the cells.

[0004] Bipolar batteries circulate ions such as protons and hydroxide ions. However, conventional alkaline electrolytes require a unique housing design because it is difficult to separate the electrolyte between adjacent cells in the design of bipolar batteries. Although there is a strong desire to arrange all elements in a single housing for a compact battery design, this requires a complex gasket mechanism to prevent leakage of the electrolyte between cells in the stack and subsequent formation of a short circuit. Alternative designs that separate the electrolyte for each individual cell, while useful for addressing potential short circuit problems, have the problem of increasing cell size and deviating from the overall compact design desired in the industry.

Summary of the Invention

Problems to be Solved by the Invention

[0005] As will be described below, the present disclosure addresses these needs by providing a new bipolar cell design using specific separator and / or electrolyte arrangements and materials that effectively insulate the electrolyte and do not require a bulky or complex cell design. These and other advantages of the present disclosure will become apparent from the following drawings, discussion, and description.

[0006] The following summary is provided to facilitate understanding of some of the innovative features specific to the present disclosure and is not intended as a complete description. A full understanding of the various aspects of the present disclosure can be obtained by considering the entire specification, the claims, the drawings, and the summary together. The invention described in the present disclosure is set forth in the following claims.

[0007] Proton or hydroxide ion conductive batteries have several advantages such as fast ion conduction, high energy density, relatively low cost, and an improved safety profile compared to lithium-ion batteries. So far, it has been found difficult to find a way to effectively incorporate these cell types into the design of bipolar batteries. The present disclosure provides new designs and materials for efficient and compact bipolar batteries.

Means for Solving the Problems

[0008] Accordingly, there is provided a bipolar battery including two or more cells, wherein at least one of the cells includes a positive electrode active material, a negative electrode active material, a proton or hydroxide ion conductive polymer separator between the positive electrode active material and the negative electrode active material, and a bipolar metal plate associated with the negative electrode active material or the positive electrode active material. The battery may include an electrolyte including a solid polymer capable of conducting protons or hydroxide ions, but does not necessarily have to include it. The cell can take several possible forms. Optionally, the bipolar metal plate is associated with the positive electrode active material and the negative electrode active material. In some embodiments, the separator is in the form of a film, and the film is not adhered to either the negative electrode active material or the positive electrode active material. Optionally, the separator is in the form of a coating on the negative electrode active material, the positive electrode active material, or both. In some embodiments, the positive electrode active material is attached to a positive electrode substrate, or the negative electrode active material is attached to a negative electrode substrate, or both, so that the positive electrode, the negative electrode, or both can be independently assembled in a battery stack without coating other surfaces or materials.

[0009] The separator provided in the present disclosure conducts cations or anions (exemplarily hydroxide ions) and, optionally, selectively conducts cations or anions. The ion-conductive polymer that can constitute the separator may be a hydroxide ion-conductive membrane, and optionally, the hydroxide conductive membrane includes a support polymer bonded to an amine. Alternatively, the separator may be a proton-conductive membrane, and optionally, the proton-conductive membrane includes a perfluorinated polymer and optionally a perfluorosulfonic acid (PFSA) polymer. The ion-conductive polymer of the separator may be coated on an ion-conductive substrate, impregnated therein, or in other forms, and the ion-conductive polymer optionally includes a perfluorinated polymer and optionally a perfluorosulfonic acid (PFSA) polymer. In some embodiments, the ion-conductive substrate includes Pt, Pd, LaNi5, or an oxide, optionally ZrO2 or a perovskite oxide, or a combination thereof. In any of the forms described in this section, the separator further includes one or more ion-conductive organic powders.

[0010] The battery obtained according to any of the above has, optionally, a Coulomb efficiency of 70% or more, indicating the high efficiency of the battery provided by the present disclosure.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0012] There is provided a bipolar battery that can be used in a proton or hydroxide ion conducting cell system while meeting the need for a compact bipolar cell design. The battery includes one or more separators that can selectively conduct protons or hydroxide ions, and optionally a separator that provides electrical insulation between the negative electrode active material and the corresponding positive electrode active material to prevent short circuit and premature discharge of the battery during storage.

[0013] The present disclosure uses an ion-conductive polymer separator that can selectively transport protons or hydroxide ions depending on the types of negative electrode active material and positive electrode active material used in the system. By using a selective ion-conductive polymer, a material that contains little or no liquid electrolyte can be formed compared to conventional alkaline batteries, thus eliminating the need for a complex bipolar cell design while maintaining a compact structure.

[0014] A new generation of proton-conductive batteries operates by circulating hydrogen between the negative electrode and the positive electrode. As a result, the negative electrode forms a hydride of one or more elements at the negative electrode during charging. This hydride is reversibly formed such that during discharge, the hydride produces both protons and electrons while becoming the elemental portion of the negative electrode active material. The half-reaction equation at the negative electrode can be represented by the following half-reaction equation.

[0015] **[Equation]** In the formula, M is one or more transition metals or post-transition metals, or contains one or more transition metals or post-transition metals.

[0016] The half - reaction equations of the corresponding positive - electrode reactions are typically as follows.

[0017] [Number] In the formula, M c is one or more arbitrary metals suitable for the positive - electrode electro - chemical active material, and is optionally Ni.

[0018] In contrast to proton - conducting batteries, other battery chemistries use hydroxide ions as the charge conductor between the negative electrode and the positive electrode. These require an electrolyte and a separator capable of conducting anions such as hydroxide ions. The half - reaction equations of hydroxide - ion - conducting batteries are as follows.

[0019] M (s) + 2OH - (aq) → MO (s) + H2O (l) + 2e -

[0020] 2MO2(s) + H2O (l) + 2e - →M2O3(s) + 2OH - (aq).

[0021] Although the batteries of the present disclosure utilize these cell chemistries, it is possible to use them in a compact and high - energy - density bipolar - cell form.

[0022] As used herein, the term "battery" means a collection of two or more cells in series, as configured in a bipolar battery. A "cell" includes a positive - electrode active material, a negative - electrode active material, and a separator as provided in the present disclosure, and functions to reversibly store energy electro - chemically.

[0023] In the present disclosure, the term "selectivity" with respect to ion transport is defined as the ability of an element (such as a separator, an electrolyte, or a combination thereof) to transport one ionic species with higher efficiency than other ionic species. As an example, an anion-selective medium preferentially transports a certain anion over a cation and optionally over other anions. A cation-selective medium preferentially transports a certain cation over an anion and optionally over other cations.

[0024] The "negative electrode" in the present disclosure includes an electrochemically active material that functions as an electron acceptor during charging.

[0025] The "positive electrode" in the present disclosure includes an electrochemically active material that functions as an electron donor during charging.

[0026] When an atomic ratio (at%) is shown without a specific definition, the atomic ratio is expressed based on the amounts of all elements except hydrogen and oxygen in the described material.

[0027] The present disclosure provides a bipolar battery employing an ion-conductive solid polymer material that can function as a separator only or as both a separator and an electrolyte material. The separator conducts either protons or hydroxide ions between the negative and positive electrodes of the individual cells of the bipolar battery as charge carriers and, optionally, selectively conducts either protons or hydroxide ions. The separator may be in one or more of a plurality of desirable forms, such as a film of an ion-conductive polymer, a porous film containing an ion-conductive polymer, a film of an ion-conductive polymer adhered to a porous substrate containing the same or a different ion-conductive polymer, or other desirable forms. In any desired form, the separator may further include one or more types of ion-conductive inorganic powders contained, optionally within the ion-conductive polymer, within one or more regions of the separator material. These forms of the separator enable, optionally, a bipolar battery having excellent power density to be formed by a combination of a negative electrode, a positive electrode, or both, with a substrate that can be distinguished from the bipolar plate, provided internally or on the surface, without the need for a complex design form for maintaining an electrolyte in any one region of the cell.

[0028] Accordingly, there is provided a bipolar battery including two or more cells, wherein at least one of the cells includes a positive electrode active material, a negative electrode active material, a proton or hydroxide ion conductive polymer separator between the positive electrode active material and the negative electrode active material, and a bipolar metal plate associated with the negative electrode active material or the positive electrode active material. The bipolar metal plate optionally has a negative electrode active material coated on a first side and a positive electrode active material coated on a second side. Thereby, the bipolar battery includes at least two of the above cells sandwiched between two current collectors that are in the middle or at the ends of a bipolar cell stack. It is understood that if there are only two such cells, there may be one bipolar metal plate shared between these two cells. In some embodiments, the separator material itself can function to conduct desired ions between the positive electrode active material and the negative electrode active material, such that the separator of the bipolar battery is used without an additional electrolyte material. In other embodiments, the electrolyte of the bipolar battery provided in the present disclosure may be a solid polymer electrolyte, a liquid electrolyte, or any combination thereof, if the electrolyte can be completely contained within the separator, or may be adjacent to the separator on one or both sides between the separator and the negative electrode active material and / or the positive electrode active material.

[0029] An example of a bipolar battery according to some aspects of the present disclosure is shown in FIG. 1. Note that FIG. 1 is merely an example and does not limit the structure of the bipolar battery. The bipolar battery includes current collectors 10, 10' disposed at both ends of the stack. On the cell side of the current collectors, active materials such as positive electrode active materials 20, 20' or negative electrode active materials 30, 30' are provided. Ion-conductive polymer separators 40, 40' are provided adjacent to the active materials. A bipolar plate, a bipolar plate 50 which is optionally made of metal, separates two cells. The bipolar plate may be shared between two cells, or two such bipolar plates may be electrically connected to each other and function to separate the two cells in other respects. In a particular aspect, the bipolar plate is shared between adjacent cells of the battery. Optionally, one of the two current collectors 10, 10' is part of the housing of the battery or functions as the housing of the battery. In such a configuration, a gasket or O-ring 60 that can function not only to insulate the battery from the external environment but also as an insulator between the two current collectors to prevent short-circuiting of the bipolar battery may be accommodated between the two current collectors.

[0030] The bipolar battery provided in the present disclosure includes a proton or hydroxide ion-conductive polymer separator. In some aspects, the separator may be composed of an ion-conductive film. The ion-conductive film may have film properties (e.g., rigidity) sufficient to be laminated on or between the negative electrode active material and the positive electrode active material, and may provide an appropriate thickness to physically separate the negative electrode active material from the positive electrode active material. The separator in these aspects may be completely formed before cell assembly and simply laminated with other elements of the cell during cell formation.

[0031] In other embodiments, the separator may be formed as a coating that contacts the negative electrode active material, the positive electrode active material, or both. For example, an electrode (negative or positive) can be formed such that the separator material can be applied after, during, or before polymerization of the polymer material so as to directly form a coating on the surface of the desired negative electrode, positive electrode, or both. In some embodiments, optionally, the coating covers the electrode active material to which the coating is applied such that the electrode active material contacts only the current collector substrate, any support substrate, and the separator material.

[0032] The separator includes one or more ion-conductive polymers. The ion-conductive polymer can be any material that optionally has conductivity or selective conductivity for protons or hydroxide ions due to the properties of the material, or any material that is modified later to be capable of conducting protons or hydroxide ions, optionally selectively. The separator is located between the negative electrode and the positive electrode of each cell. In some embodiments, the surface area of the separator may be larger than the areas of the adjacent positive and negative electrodes. The separator may completely separate the positive electrode active material from the negative electrode active material within each cell. The edge of the separator may contact the periphery of the bipolar plate or the current collector plate so as to completely separate the negative electrode active material from the positive electrode active material when no negative electrode active material or positive electrode active material is disposed on the surface of the bipolar plate or the current collector plate. The separator functions to prevent short-circuiting of the cell due to dendrite formation and optionally selectively allows a liquid electrolyte (if present), ions, electrons, or any combination of these elements to pass through the separator, or to be conducted by the separator. The separator may be prepared from a non-conductive material such as a polymer film, and optionally, a porous polymer film, a glass mat, a porous rubber, an ion-conductive gel, or a natural material. Exemplary materials useful as the separator include porous or non-porous high molecular weight or ultra-high molecular weight polyolefin materials that function as a base or an ion-conductive polymer in the separator.

[0033] The separator may be in the form of an ion-conductive polymer (ICP) membrane that can function as a stand-alone system for transporting ions between the positive and negative electrodes of a cell, optionally as shown in Figure 2A. Alternatively, the ICP membrane may be associated with an ion-conductive solid support, optionally as shown in Figure 2B. Here, the term "solid" with respect to the support provided in the present disclosure means that the support does not transmit ICP through the support during operation of the cell. The ICP may be laminated, coated, or otherwise disposed in direct contact on the support to form the entire separator.

[0034] In some embodiments, the separator may be formed from a porous substrate that includes pores or serpentine paths through the separator, optionally as shown in Figures 2C and D, such that electrolyte, ions, electrons, or any combination thereof can pass through the separator. The separator may be formed by filling the pores of the substrate with one or more types of ICP. Such highly porous substrate materials can be formed from known porous ceramic or polymer materials. The ICP may be housed in the pores to form a conduction path for ions to flow or conduct through the separator material. In some embodiments, optionally as shown in Figures 2D-I, when forming the entire separator, the porous separator material is further coated on one or both sides with a sheet or film of ICP. Optionally, the ICP may be coated on an electrically insulating material such as polypropylene that forms the structural surface of the separator.

[0035] The porous substrate optionally has a porosity defined as the ratio of the pore volume (i.e., the interstitial volume) to the total volume of the porous substrate and can be measured by any method known in the art, such as mercury intrusion porosimetry, gas adsorption, or capillary flow porosimetry based on the flow of a fluid through a membrane, as obtained by a capillary flow method. The porosity is optionally 20% or more, optionally 30% or more, optionally 40% or more, optionally 50% or more, optionally 60% or more, optionally 70% or more, optionally 80% or more. In some embodiments, the porosity ranges from 20% to 80%, optionally from 30% to 60%, optionally from 40% to 50%.

[0036] The separator provided in the present disclosure is an ion-conductive polymer or includes an ion-conductive polymer. Examples of ion-conductive polymers include those that conduct protons or hydroxide ions, optionally selectively conduct protons or hydroxide ions, and have electrical insulation properties. The electrical resistivity of the separator used in the cell provided in the present disclosure is 1x10 -4 ohm·m 2 or less, optionally 8x10 -5 ohm·m 2 or less, optionally 6x10 -5 ohm·m 2 or less, optionally 4x10 -5 ohm·m 2 or less, optionally 3x10 -5 ohm·m 2 or less.

[0037] Proton-conductive materials suitable for use as the ICP of the separator include, but are not limited to, hydrated acidic polymers containing mutually penetrating hydrophobic domains and hydrophilic domains, where the hydrophobic domains can provide the structural dimensions of the polymer and the hydrophilic domains enable selective proton conduction. Examples of such polymers include those formed from poly(styrene sulfonate). Other examples of proton-conductive materials include, but are not limited to, perfluorinated polymers such as perfluorosulfonic acid (PFSA) polymers such as NAFFION. In some embodiments, the polymer is a polyaromatic polymer that has proton conductivity while being electrically insulating. In a further embodiment, the proton-conductive polymer is a composite material in which the proton-conductive material is embedded in or adhered to a polymer matrix that is optionally non-proton-conductive.

[0038] The proton-conductive polymer optionally has proton conductivity while being electrically insulating. The proton conductivity is optionally 0.1 mS / cm or more, optionally 0.2 mS / cm or more, and optionally 1 mS / cm or more when measured at room temperature.

[0039] In other embodiments, the ion conductive polymer is a hydroxide ion conductive polymer such as an anion exchange membrane (AEM) or an anion exchange polymer. An anion exchange membrane or anion exchange polymer (AEP) is generally based on a polymer material or a polymer material containing the same, which is linked to one or more cationic groups that function to enable the conduction of anions through the membrane material. These membranes or polymers may include a polyolefin linked to an anion exchange material or a polyolefin in which an anion exchange material is embedded to enable selective conduction of anions. As another example, there is a direct anion exchange polymer itself that can coat the membrane, be embedded in the membrane, and / or coat one or more electrodes. Optionally, the AEM is a cationic group added to the polymer material or includes a cationic group added to the polymer material. Examples of such cationic groups include quaternary ammonium groups or imidazolium groups. Other examples include those based on guanidinium, DABCO, benzimidazolium, pyrrolidinium, sulfonium, phosphonium, and ruthenium-based cations. Other exemplifications of anion exchange membranes are described in WO 2015 / 015513.

[0040] In some examples, the AEM or AEP is based on or includes a modified benzimidazolium such as poly[2,2'-(2,2'',4,4'',6,6''-hexamethyl-p-terphenyl-3,3''-diyl)-5,5'-bibenzimidazole] (HMT-PBI) or its methylated form HMT-PMBI. Other examples include poly[2,2′-(m-mesitylene)-5,5′-bis(N,N′-dimethylbenzimidazolium)] (Mes-PDMBI,2-X-) and poly[2,2′-(m-phenylene)-5,5′-bis(N,N′-dimethylbenzimidazolium)] (PDMBI,3-X-). Such materials are commercially available from IONOMR (Vancouver, CA).

[0041] Such anion exchange polymers are optionally in the form of a sheet or film. In other embodiments, the anion exchange polymer is bound to, coated on, or impregnated in the polyolefin material, or a combination thereof. Exemplary polyolefin materials suitable for anion exchange membranes, proton exchange membranes, or both include porous or non-porous high molecular weight or ultra-high molecular weight polyolefin materials that function as the ionic conductive polymer of the base or separator. Exemplary materials include those based on poly(arylene ether), poly(biphenyl alkylene), and polystyrene block copolymers, or these materials. Optionally, the polymer backbone is polysulfone, poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE), polybutylene, poly(butyl acrylate), styrene-ethylene-butylene-styrene, polypropylene, polyethylene, polyvinylidene fluoride or polyvinylidene difluoride (PVDF), etc., or includes them.

[0042] The ionic conductive polymer optionally has conductivity for hydroxide ions while having electrical insulation. The hydroxide ion conductivity is optionally 0.1 mS / cm or more when measured at room temperature, optionally 0.2 mS / cm or more, optionally 1 mS / cm or more, optionally 2 mS / cm or more, optionally 3 mS / cm or more, optionally 5 mS / cm or more, optionally 10 mS / cm or more, optionally 13 mS / cm or more, optionally 15 mS / cm or more.

[0043] The separator provided in the present disclosure may include one or more ion-conductive inorganic powders (ICIPs). The ion-conductive inorganic powders may, optionally, be in the form of a stand-alone membrane, as a coating on a substrate, impregnated within the pores of a porous substrate, or embedded within an ion-exchange membrane, as shown in FIGS. 2E - K, or any combination thereof. Examples of ICIPs include untreated perovskite oxides and treated perovskite oxides. A perovskite-type oxide is a material having the general formula ABO3, where a larger A cation coordinates to 12 anions, and the B cation occupies 6 coordination sites, forming a network of vertex-sharing BO6 octahedra. The A cation may be a rare earth, alkali, or alkaline earth element. Typically, the B element is one or more transition metals. In some embodiments, A may be Ca, Sr, La, Na, K, Mg, or a combination thereof. Optionally, B may be Al, Ti, Nb, Ta, Ga, or a combination thereof. More specific examples include, but are not limited to, substituted or unsubstituted NaNb 0.5 Al 0.5 O 2.5 , KNb 0.5 Al 0.5 O 2.5 , Ba2NaMoO 5.5 , Ba2LiMoO 5.5 , Ba2NaWO 5.5 , CaTi 0.95 Mg 0.05 O3- δ , Nd 0.9 Ca 0.1 AlO3- δ , La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 , Ba2In2O5, Ba3In2ZrO8, Bi4V2O 11 , Bi4V 1.8 Cu 0.2 O 11 - δ , La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 2.815, BaCeO3, Ba2SnYO 5.5 , BaTbO3, BaZrO3, SrCeO3, Ba3CaNb2O9, LaScO3, CaZrO3, Gd2O3, SrTiO3, La2Zr2O7, CaSrO3, Nd2O3, SrZrO3, Er2O3, LaPO4, and LaErO3, etc. The processed perovskite oxide may be a product of a perovskite oxide chemically modified through specific processes.

[0044] The separator may contain one or more ion-conductive polymers, ion-conductive inorganic powders, or both, impregnated on or in an ion-conductive substrate (or both). Examples of the ion-conductive substrate include those formed of one or more transition metals or their oxides, hydroxides, or oxyhydroxides. By way of example, but not limited to, Pt, Pd, LaNi5 are included. Alternatively or additionally, the ion-conductive substrate for use in the separator can include oxides such as metal oxides (e.g., ZrO2, CeO2, TiO2) or perovskite oxides as otherwise described in the present disclosure.

[0045] The separator may be provided in the form of a membrane or film and simply laminated between the negative electrode active material and the positive electrode active material, or may be coated on the negative electrode active material, the positive electrode active material, or both. The formation of the ion-conductive polymer separator can be achieved from a desired precursor material by a general polymerization method known in the art, illustratively the free radical polymerization method. The ion-conductive polymer layer may optionally be coated on a desired electrode surface, such as by polymerizing the material on the desired electrode surface. The precursor material may be combined with a solvent and coated on the electrode material. The solvent used for the polymerization reaction of the polymer is not particularly limited. Illustratively, the solvent may be a hydrocarbon solvent (methanol, ethanol, isopropyl alcohol, toluene, heptane, and xylene), an ester solvent (ethyl acetate and propylene glycol monomethyl ether acetate), an ether solvent (tetrahydrofuran, dioxane, and 1,2-diethoxyethane), a ketone solvent (acetone, methyl ethyl ketone, and cyclohexanone), a nitrile solvent (acetonitrile, propionitrile, butyronitrile, and isobutyronitrile), a halogen solvent (dichloromethane and chloroform), etc. As an example, one or more ion-conductive polymer separator precursor materials are combined with a solvent on the electrode surface, optionally held by the structure of the electrode itself, the container in which the electrode is placed, or other holding system, and the precursor material is dried or polymerized on the electrode surface, thereby forming a layer of a desired size and thickness on the electrode surface.

[0046] The separator provided by the present disclosure has a thickness. The thickness should be sufficient to achieve a desired electrical resistance and physically separate the negative electrode from the positive electrode, while not being so thick as to undesirably impede the efficient transport of desired ions through the separator. Illustratively, the thickness of the separator is from 1 micron to 100 microns or more. Optionally, the thickness of the separator is from 1 micron to 50 microns, optionally from 10 microns to 30 microns, and optionally from 20 microns to 30 microns.

[0047] As described above, the separator provided in the present disclosure may be in the form of a film or a membrane, may be coated on one or more other components of the cell, or may be a combination thereof. FIG. 3 shows an exemplary configuration of the separator with respect to other elements within the bipolar cell. In some embodiments as shown in FIG. 3A, the cell of the bipolar battery includes a bipolar metal plate 10 electrically associated with a negative electrode active material 30, and the negative electrode active material is separated from the positive electrode active material 20 by a separator 40 provided in the present disclosure. The positive electrode active material may be electrically associated with a current collector or a second bipolar metal plate as shown in FIG. 3. FIG. 3A shows a configuration in which the negative electrode active material, the positive electrode active material, and the separator are each in the form of an independent film or membrane so that they can be individually stacked in a desired configuration to form a bipolar battery.

[0048] In other exemplary embodiments as shown in FIG. 3B, the bipolar cell may include a separator 40 included as a coating on the negative electrode 30 or the negative electrode active material. The coating may be laminated on the surface of the negative electrode opposite to the surface in contact with the bipolar metal plate 10, and optionally may be laminated over the entire surface. In this way, the separator not only enables the desired ion transport between the negative electrode and the positive electrode during the cell cycle, but also completely separates the two to prevent short circuits and undesired self-discharge.

[0049] Optionally, as shown in FIG. 3C, the separator 40 may be coated on both the negative electrode 30 and the positive electrode 20. The separator may partially or entirely cover either the negative electrode or the positive electrode, or both, as long as the separator material is provided over the entire surface area of the smaller of the surface areas of the negative electrode or the positive electrode. Laminating the material in this way enables efficient separation and ion conduction between the negative electrode and the positive electrode.

[0050] In another exemplary aspect as shown in FIG. 3D, the negative electrode 30, the positive electrode 20, or both themselves may be coated on individual current collector substrates or bipolar metal plates 10, 10' according to the desired positions of the negative and positive electrodes. Then, the obtained coated bipolar metal plates or current collector substrates may be laminated to realize a functional bipolar cell and separated by the separator 40 film or film described in the present disclosure.

[0051] In yet another alternative aspect, the separator material 40 may be coated on the negative electrode 30, the positive electrode 20, or both, whereby the negative electrode active material, the positive electrode active material, or both themselves may be coated on the bipolar metal plate 10 or the current collector substrate.

[0052] In the exemplary aspect shown in FIG. 3E, both the negative electrode active material 30 and the positive electrode active material 20 are coated on their respective bipolar metal plates 10, 10'. And the separator material 40 is coated on the surface of the negative electrode active material 30. Although FIG. 3E shows the coating on the negative electrode active material, in the present disclosure, although not shown, it is also conceivable to coat the separator on the positive electrode active material. Alternatively, as shown in FIG. 3F, one or more of the same or different separator materials 40, 40' may be coated on both the negative electrode active material 30 and the positive electrode active material 20, whereby a bipolar cell structure can be obtained by laminating the plates.

[0053] The manufacture of a bipolar metal plate or current collector substrate with a coating having a negative electrode active material, a positive electrode active material, or both typically involves coating a metal substrate with a layer of the electrode active material in the presence of a solvent. An exemplary solvent commonly used is N-methyl-2-pyrrolidone (NMP). It may also include a binder such as polyvinylidene fluoride (PVDF). After applying the coating of the electrode material to the substrate, the coating may be dried by methods such as heating, exposure to the ambient atmosphere, exposure to microwave energy or other energy. Optionally, the material may be calendared to increase the density of the coating, and the coating may be pressurized and heated. The adhesion between the coating and the substrate is usually achieved by surface roughness, chemical bonding, and / or interfacial reaction or compound.

[0054] As described above, the negative electrode, the positive electrode, or both may function as a stand-alone film that can be simply laminated on a bipolar metal plate or current collector substrate, optionally as shown in FIGS. 3A-C. The films of the negative electrode active material and the positive electrode active material may be formed by combining the respective electrode active materials with a solvent and a binder material, pressing, calendaring, spraying onto a release surface or the like, and then drying to form a film structure.

[0055] Alternatively, depending on whether the negative electrode active material or the positive electrode active material is used in a specific structure, each electrode active material may be combined with a support substrate such as a positive electrode substrate or a negative electrode substrate. The presence of the support substrate can result in a more robust positive or negative electrode structure that can be individually laminated with the bipolar plate, current collector substrate, and separator for rapid manufacturing. Exemplary substrates for use in the negative or positive electrode are steel such as stainless steel, nickel-plated steel, aluminum (optionally an aluminum alloy), nickel or nickel alloy, copper or copper alloy, polymer, glass, or other materials that can suitably conduct or transmit the desired ions and electrons, or other such materials. One or more substrates may be in the form of a sheet (optionally a foil), a solid substrate, a porous substrate, a grid, a foam, or a foam coated with one or more metals, a perforated metal material such as perforated nickel-plated stainless steel, or other forms. In some embodiments, the negative electrode substrate, the positive electrode substrate, or both are in the form of a foil. Optionally, the grid may include an expanded metal grid or a perforated foil grid. The negative electrode substrate, the positive electrode substrate, or both do not need to be in direct contact with the bipolar metal plate or the current collector substrate and may be housed within each electrode active material. However, in some embodiments, the negative electrode substrate, the positive electrode substrate, or both are in electrical contact with the bipolar metal plate and / or the current collector substrate and are optionally in direct electrical contact.

[0056] The negative electrode active material used in the bipolar cell provided by the present disclosure optionally includes one or more hydrogen storage materials. The negative electrode active material optionally includes Si x M 1-x and here, M includes one or more of a Group 14 element other than Si, a transition metal, a post-transition metal, or an alkali or alkaline earth element as a dopant, and 0 < x < 1. Examples of such materials are AB x type hydrogen storage materials, where A is a hydride-forming element, B is a non-hydride-forming element, and x is 1 to 5. By way of example, AB, AB2, AB3, A2B7, A5B known in the art 19and AB5-type materials. Examples of the metal hydride-forming metal component (A) include, but are not limited to, optionally titanium, zirconium, vanadium, hafnium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, yttrium, or combinations thereof, or other metals such as mischmetal. Examples of the B (non-metal hydride-forming) component include, optionally, metals selected from the group consisting of aluminum, chromium, manganese, iron, nickel, cobalt, copper, tin, or combinations thereof. In some embodiments, the AB x type material that may further be included in the negative electrode electrochemical active material is disclosed, for example, in U.S. Patent No. 5,536,591 and U.S. Patent No. 6,210,498. Optionally, the Group 14 element-free hydrogen storage material is a material as described in Young, et al., International Journal of Hydrogen Energy, 2014; 39(36):21489-21499 or Young, et al., Int. J. Hydrogen Energy, 2012; 37:9882. Optionally, the negative electrode active material is a material as described in U.S. Patent Application Publication No. 2016 / 0118654. In some embodiments, the negative electrode active material includes hydroxides, oxides, or oxyhydroxides of Ni, Co, Al, Mn, or combinations thereof, and optionally is a material as described in U.S. Patent No. 9,502,715. Optionally, the negative electrode active material includes transition metals such as Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Au, Cd, or combinations thereof, and optionally is a material as disclosed in U.S. Patent No. 9,859,531.

[0057] In some embodiments, the formula Si x M 1-xM therein is optionally one or more Group 14 elements. Group 14 elements include carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). In some embodiments, the Group 14 element excludes Pb. Optionally, the Group 14 element is C, Si, Ge, or any combination thereof. In some embodiments, the negative electrode electrochemically active material includes Si. Optionally, the negative electrode electrochemically active material includes C. Optionally, the negative electrode electrochemically active material includes Ge. Optionally, M is C, Ge, or any combination thereof. Optionally, M is C. Optionally, M is Ge. Optionally, x is 0.5 or more, optionally x is 0.55 or more, optionally x is 0.6 or more, optionally x is 0.65 or more, optionally x is 0.7 or more, optionally x is 0.71 or more, optionally x is 0.72 or more, optionally x is 0.73 or more, optionally x is 0.74 or more, optionally x is 0.75 or more, optionally x is 0.76 or more, optionally x is 0.77 or more, optionally x is 0.78 or more, optionally x is 0.79 or more, optionally x is 0.8 or more, optionally x is 0.85 or more, optionally x is 0.9 or more, optionally x is 0.95 or more, optionally x is 0.96 or more, optionally x is 0.97 or more, optionally x is 0.98 or more, or optionally x is 0.99 or more.

[0058] The negative electrode active material is provided in powder form. That is, the negative electrode electrochemically active material is solid at 25 degrees Celsius (°C) and does not include a substrate. The powder may be held together by a binder that associates the powder particles in a layer coated on or within a substrate, a bipolar metal plate, or a current collector substrate during the formation of the negative electrode.

[0059] Also, the bipolar cell provided by the present disclosure includes a positive electrode containing a positive electrode active material. The positive electrode active material has the ability to absorb and desorb hydrogen ions in the battery cycle such that the positive electrode active material functions in combination with the negative electrode active material to generate current. Exemplary materials suitable for use as the positive electrode active material include metal hydroxides. Examples of metal hydroxides that can be used as the positive electrode active material include those described in U.S. Patent No. 5,348,822, U.S. Patent No. 5,637,423, U.S. Patent No. 5,366,831, U.S. Patent No. 5,451,475, U.S. Patent No. 5,455,125, U.S. Patent No. 5,466,543, U.S. Patent No. 5,498,403, U.S. Patent No. 5,489,314, U.S. Patent No. 5,506,070, U.S. Patent No. 5,571,636, U.S. Patent No. 6,177,213, and U.S. Patent No. 6,228,535.

[0060] In some embodiments, the positive electrode active material comprises a hydroxide of Ni alone or in combination with one or more additional metals. Optionally, the positive electrode active material comprises Ni and one, two, three, four, five, six, seven, eight, nine or more additional metals. Optionally, the positive electrode active material comprises Ni as the sole metal.

[0061] Optionally, the positive electrode active material comprises one or more metals selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi its hydride, its oxide, its hydroxide, its oxyhydroxide, or any combination thereof. Optionally, the positive electrode active material comprises one or more of Ni, Co, Mn, Zn, Al, Zr, Mo, Mn, rare earths, or combinations thereof. In some embodiments, the positive electrode active material comprises Ni, Co, Al, or combinations thereof.

[0062] The positive electrode active material may contain Ni. Optionally, Ni is present at 10 atomic percent (at%) or more based on the total metal in the positive electrode active material. Optionally, Ni is present at 15 at% or more, optionally 20 at% or more, optionally 25 at% or more, optionally 30 at% or more, optionally 35 at% or more, optionally 40 at% or more, optionally 45 at% or more, optionally 50 at% or more, optionally 55 at% or more, optionally 60 at% or more, optionally 65 at% or more, optionally 70 at% or more, optionally 75 at% or more, optionally 80 at% or more, optionally 85 at% or more, optionally 90 at% or more, optionally 91 at% or more, optionally 92 at% or more, optionally 93 at% or more, optionally 94 at% or more, optionally 95 at% or more, optionally 96 at% or more, optionally 97 at% or more, optionally 98 at% or more, optionally 99 at% or more. Optionally, the only metal in the positive electrode electrochemical active material is Ni.

[0063] The negative electrode active material, the positive electrode active material, or both may optionally be in powder or particle form. The particles may be held together by a binder to form a layer on the current collector when forming the negative or positive electrode. Optionally, a binder suitable for use in forming the negative electrode, the positive electrode, or both is any binder known in the art suitable for such purposes and for proton conduction.

[0064] Exemplarily, the binder for forming the negative electrode, positive electrode, or both is not limited to the following, but includes a polymer binder material. Optionally, the binder material is an elastomer material, and optionally, it is styrene-butadiene (SB), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene-butadiene-styrene block copolymer (SEBS). Specific examples of the binder include, but are not limited to, polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), Teflon (registered trademark)-treated acetylene black (TAB-2), styrene-butadiene binder material, and / or carboxymethyl cellulose (CMC). The exemplification is described in U.S. Patent No. 10,522,827. The ratio of the electrochemical active material to the binder is optionally from 4:1 to 1:4. Optionally, the ratio of the electrochemical active material to the binder is from 1:3 to 1:2.

[0065] The positive electrode, negative electrode, or both may further include one or more additives mixed with the active material. The additive is optionally a conductive material. The conductive material is preferably conductive carbon. Examples of the conductive carbon include graphite. Other examples include materials containing graphite-like carbon such as graphitized coke. Still other examples of the possible carbon materials include non-graphite-like carbon that can be amorphous, non-crystalline, and disordered, such as petroleum coke and carbon black. The conductive material is optionally present in the negative electrode or positive electrode in a weight percentage (wt%) of 0.1 wt% to 20 wt%, or any value or range therebetween.

[0066] The negative electrode or the positive electrode can be formed by any method known in the art. For example, a slurry can be formed by combining a negative electrode electrochemically active material or a positive electrode electrochemically active material with a binder and optionally a conductive material in a suitable solvent. By applying this slurry onto a bipolar metal plate, a current collector substrate or an electrode support and drying it to evaporate some or all of the solvent, an electrochemically active layer can be formed.

[0067] The cells of the bipolar battery provided by the present disclosure include a bipolar metal plate associated with a negative electrode active material, a positive electrode active material, or both. On the first side of the bipolar metal plate, the negative electrode active material is in electrical contact with the bipolar metal plate, and on the second side of the bipolar metal plate, the positive electrode active material is in electrical contact with the bipolar metal plate. The bipolar metal plate may be formed of any suitable electronically conductive material. Optionally, the bipolar metal plate is steel such as stainless steel, nickel-plated steel, aluminum (optionally an aluminum alloy), nickel or a nickel alloy, copper or a copper alloy, a polymer, glass, or other material that can suitably conduct or transmit the desired electrons, or other such materials. The bipolar metal plate may be in the form of a sheet (optionally a foil), a solid substrate, a porous substrate, a grid, a foam or a foam coated with one or more metals, or other forms. In some embodiments, the bipolar metal plate is in the form of a foil. Optionally, the grid may include an expanded metal grid or a perforated foil grid.

[0068] The bipolar battery provided by the present disclosure may be negative electrode limited or positive electrode limited. The limited type in relation to the positive electrode or the negative electrode is relative to the counter electrode and can be limited in terms of capacity, surface area, or both. Optionally, the battery is positive electrode limited, that is, the capacity, surface area, or both of the positive electrode are smaller than those of the negative electrode. In some embodiments, the ratio of the capacity of the positive electrode to the negative electrode is less than 1, optionally 0.99 or less, optionally 0.98 or less, 0.97 or less, 0.96 or less, 0.95 or less, 0.9 or less, 0.85 or less, or 0.8 or less. Optionally, the ratio of the surface area of the positive electrode to the negative electrode is less than 1, optionally 0.99 or less, optionally 0.98 or less, 0.97 or less, 0.96 or less, 0.95 or less, 0.9 or less, 0.85 or less, or 0.8 or less.

[0069] In some embodiments, the separator provided by the present disclosure can function as both a separator and an electrolyte due to the ability of the separator to conduct protons or hydroxide ions and provide the electrical insulation properties necessary to function as a separator between the negative electrode and the positive electrode. However, in some embodiments, it is understood that the bipolar battery may further include a separate electrolyte, optionally a liquid or solid polymer electrolyte. The electrolyte may be impregnated in the separator or may be adjacent to the separator on one or both sides between the separator and the adjacent electrode.

[0070] The electrolyte may be any proton or hydroxide ion conductive electrolyte. Optionally, the electrolyte is an alkali hydroxide containing potassium, sodium, calcium, lithium hydroxide, or any combination thereof. Specific and non-limiting examples of the electrolyte include KOH, NaOH, LiOH, Ca(OH)2, etc. at any suitable concentration, optionally 20 - 45 wt% by weight in water.

[0071] In other embodiments, the electrolyte is optionally a solid polymer electrolyte. Examples of solid polymer electrolytes include polymer materials such as poly(ethylene oxide), poly(vinyl alcohol), poly(acrylic acid), or a copolymer of epichlorohydrin and ethylene oxide, and may optionally be a polymer material containing one or more of potassium, sodium, calcium, lithium hydroxides, or any combination thereof.

[0072] The electrolyte may optionally be one or more organic solutions, or may contain one or more organic solutions. Examples of organic electrolyte materials include ethylene carbonate (EC), propylene carbonate (PC), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), or polyvinyl alcohol (PVA) with an added acid, and proton-conductive ionic liquids known in the art. Examples of proton-conductive ionic liquids include, but are not limited to, 1-butyl-3-methylimidazolium (BMIM), 1-ethyl-3-methylimidazolium (EMIM), 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1,2,3-trimethylimidazolium, tris-(hydroxyethyl)methylammonium, acetates, sulfonates, or borates of 1,2,4-trimethylpyrazolium, or those containing combinations thereof. Specific examples include diethylmethylammonium trifluoromethanesulfonate (DEMA TfO), 1-ethyl-3-methylimidazolium acetate (EMIM Ac), or 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM TFSI).

[0073] The stack of cells is optionally sandwiched at both ends by current collector substrates. The current collector substrates can be formed of any material having a conductivity suitable for transmitting electrons from the associated cells to the external environment. The current collector substrates can be formed of steel such as stainless steel, nickel-plated steel, aluminum (optionally an aluminum alloy), nickel or a nickel alloy, copper or a copper alloy, or other such materials. For corrosion resistance in an acidic electrolyte, the current collector substrates may be formed of stainless steel. Optionally, both the negative and positive current collector substrates of the cell stack are formed of nickel-plated stainless steel.

[0074] The current collector is optionally in the form of a sheet and may be in the form of a foil, a solid substrate, a porous substrate, a grid, a foam or a foam coated with one or more metals, or other forms known in the art. In some embodiments, the current collector is in the form of a foil. Optionally, the grid may include an expanded metal grid or a perforated foil grid.

[0075] The current collector or substrate enables the movement of electrons from the current collector to a region outside the cell so that the electrons generated during discharge of the cell can be used to power one or more devices, and may include one or more tabs for connecting one or more current collectors to a circuit. The tabs can be formed of any suitable conductive material (e.g., Ni, Al, or other metals) and can be welded to the current collector. Optionally, each electrode has one tab.

[0076] The stack of bipolar battery cells can be housed in a cell case (e.g., a housing). The housing may be in the form of a metal or polymer can, or a laminate film such as a heat-sealable aluminum foil like an aluminum-coated polypropylene film. Thus, the bipolar battery provided by the present disclosure may be of any known cell shape, and illustratively, may be a button battery, a pouch battery, a cylindrical battery, or other suitable form. In some embodiments, the housing is in the form of a flexible film, optionally a polypropylene film. Such a housing is commonly used to form a pouch cell. The proton-conducting battery may have any suitable form or shape, and may be cylindrical or prismatic.

[0077] The bipolar battery includes two or more cells, each cell is separated by a bipolar metal plate, and current collector substrates are present at each end of the stack. The bipolar battery may have two or more cells, and optionally, may have three or more cells, optionally four, five, six, seven, eight, nine, ten or more cells in a stacked arrangement.

[0078] The bipolar battery provided by the present disclosure has a surprisingly high Coulombic efficiency. The Coulombic efficiency of the present disclosure can be measured as the value obtained by adding the discharge capacities (unit: mAh) at 100 mAh / g per negative electrode active material, the discharge capacities (unit: mAh) at 24 mAh / g per negative electrode active material, and the discharge capacities (unit: mAh) at 8 mAh / g per negative electrode active material, and then dividing all the discharge capacities by the charge amount. The Coulombic efficiency of the bipolar battery provided by the present disclosure is optionally 70% or more, optionally 71%, optionally 72%, optionally 73%, optionally 74%, optionally 75%, optionally 79%, optionally 80%, optionally 81%, optionally 82%, optionally 83%, optionally 84%, optionally 85%, and the Coulombic efficiency referred to here is the stable maximum Coulombic efficiency of the battery.

[0079] Various aspects of the present disclosure are illustrated by the following non-limiting examples. The examples are for illustrative purposes only and do not impose limitations in practicing the present invention. It is understood that modifications and variations can be made without departing from the gist and scope of the present invention.

Example

[0080] Example 1 A test bipolar battery was fabricated using an anion exchange membrane as a stand-alone separator. The negative electrode was an electrode pasted on a perforated Ni-plated stainless steel plate, with a superlattice metal hydride alloy as the active material and containing multiple types of binders. The positive electrode was an electrode pasted on a Ni foam, with Co-coated Ni(OH)2 as the active material and containing multiple types of binders. The cell design was cathode-limited. The overall dimensions of the negative electrode were 14 x 23 x 0.31 millimeters (mm). The overall dimensions of the positive electrode were 10 x 18 x 0.37 mm. As the separator, an AEM8_25 anion exchange membrane from IONOMR (Vancouver, CA) was used. The negative electrode, positive electrode, and separator were immersed in a KOH-NaOH-LiOH (3N-3N-0.4N) solution for 17 hours. After immersion, the excess electrolyte was wiped off the surface, and the negative electrode, separator, and positive electrode were combined such that they were separated by a nickel plate that functioned as a bipolar metal plate and sandwiched between the Ni block current collector substrate at the negative electrode end of the battery and the Ni foam current collector substrate at the positive electrode end of the battery to create a bipolar cell. Two batteries were created. One had two cells assembled in the entire bipolar battery stack, and the other battery had five cells assembled in the entire bipolar battery stack.

[0081] The following cycles were performed on the battery: charge at 0.05 C (14.45 mA / g per gram of the positive electrode active material of each cell) for 12 hours (hr) (60% state of charge); rest for 1 minute (min); discharge at 0.05 C (14.45 mA / g); rest for 1 minute; discharge at 0.025 C (7.2 mA / g); rest for 1 minute; discharge at 0.0125 C (3.6 mA / g); rest for 1 minute; discharge at 0.01 C (2.9 mA / g) until the final cut-off voltage (4 volts (V) for a 5-cell stack and 1.6 V for a 2-cell stack). In these cells, 1 C is equal to 289 mA / g calculated from a standard positive electrode of 289 mAh / g per gram of the active material weight.

[0082] Table 1 shows the capacity (mAh) per gram of the positive electrode active material in the first 16 cycles of the 5-cell battery.

Table 1

[0083] Example 2 A second battery identical to the 2-cell battery of Example 1 was fabricated, except that a porous polyolefin film (Shenzhen Highpower, Guangdong, China) was immersed for 10 minutes in an anion exchange solution made from 2 milliliters (ml) of ethanol and 0.04 grams (g) of an anion exchange polymer (IONOMR, Vancouver, Canada) instead of the AEM membrane. After immersion, the separator was dried in air for 1 hour. The electrodes and the separator (17 x 27 x 0.015 mm) were immersed in the same electrolyte as in Example 1.

[0084] The battery was assembled as in Example 1 and cycled under the conditions of Example 1. Table 2 shows the results of the first 25 cycles.

Table 2

[0085] Similar to the battery of Example 1, more than 95% of the discharge was from the maximum discharge rate (C / 20). The Coulomb efficiency reaches a stable efficiency of more than 90% after 17 cycles. FIG. 5 shows the charge / discharge profiles of selected cycles among the first 7 cycles. The charge termination voltage is about 3.0 V, which is about 3 times the normal charge termination voltage of a single cell, indicating the excellent cell capacity and Coulomb efficiency of the bipolar cell.

[0086] The above description of specific aspects is by way of example only and is in no way intended to limit the scope, application, or use of the invention as set forth in the claims, and these scope, application, or use may of course vary. This disclosure is provided in connection with non-limiting definitions and terms included in this disclosure. These definitions and terms are not intended to function as limiting the scope or practice of the invention, but are presented for illustrative and explanatory purposes only. Although a process or composition is described in terms of individual steps in a certain order or using specific materials, it is to be understood that the steps or materials may be interchangeable such that the description of the invention may include multiple parts or steps arranged in a number of ways readily understood by those skilled in the art.

[0087] It is to be understood that when an element is referred to as being “on” another element, that element may be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly” provided on another element, no intervening element is present.

[0088] In this disclosure, terms such as "first", "second", "third", etc. may be used to describe various elements, components, regions, layers, and / or parts. However, it should be understood that these elements, components, regions, layers, and / or parts are not limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. That is, without departing from the teachings of this disclosure, the "first element", "component", "region", "layer", or "part" described hereinafter can also be referred to as a second (or other) element, component, region, layer, or part.

[0089] The terms used in this disclosure are for the purpose of describing only specific embodiments and are not intended to be limiting. When used in this disclosure, the singular forms ("a", "an", and "the") are intended to include the plural forms including "at least one" unless the context clearly indicates otherwise. "Or" means "and / or". When used in this disclosure, the term "and / or" includes any combination of one or more of the related listed items. Further, as used herein, the terms "comprises" and / or "comprising", "includes" and / or "including" identify the presence of the described features, regions, integers, steps, operations, elements, and / or components, but are not to be construed as excluding the presence or addition of one or more other features, regions, integers, steps, operations, elements, and / or components, and / or groups thereof. The term "or combinations thereof" means a combination including at least one of the aforementioned elements.

[0090] Unless otherwise defined, all terms (including technical and scientific terms) used in this disclosure shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Further, terms as defined in commonly used dictionaries shall be interpreted to have a meaning that coincides with the meaning in the context of the relevant art and this disclosure, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0091] The patents, publications, and applications referred to herein are illustrative of the level of those of ordinary skill in the art to which the present invention pertains. These patents, publications, and applications are incorporated herein by reference to the same extent as if each individual patent, publication, or application was specifically incorporated herein by reference.

[0092] From the above, it should be understood that other modifications and variations can be made to the present invention. The above drawings, considerations, and descriptions illustrate some specific embodiments of the present invention and are not intended to be limiting in the practice of the present invention. The scope of the present invention is defined by the following claims, which include all equivalent scopes. Note that this disclosure includes the following content as embodiments. 〔Aspect 1〕 A bipolar battery including a plurality of stacked cells, wherein two or more of said cells a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a proton or hydroxide ion conductive polymer separator between said positive electrode and said negative electrode, a bipolar metal plate associated with said negative electrode or said positive electrode, optionally, an electrolyte including a solid polymer capable of conducting protons or hydroxide ions, and a battery. 〔Aspect 2〕 The battery according to Aspect 1, wherein said bipolar metal plate is associated with said positive electrode and said negative electrode. 〔Aspect 3〕 The battery according to Aspect 1, wherein said separator is in the form of a film and said film is not adhered to either the negative electrode or the positive electrode. 〔Aspect 4〕 The battery according to Aspect 1, wherein said separator is in the form of a coating on said negative electrode, said positive electrode, or both. 〔Aspect 5〕 The battery according to Aspect 1, wherein said positive electrode is formed by attaching a positive electrode active material to a positive electrode substrate, or said negative electrode is formed by attaching a negative electrode active material to a negative electrode substrate, or both. 〔Aspect 6〕 The battery according to Aspect 5, wherein said positive electrode substrate, said negative electrode substrate, or both include Ni foil, and optionally include porous Ni foil. 〔Aspect 7〕 The battery according to Aspect 1, wherein said separator selectively conducts cations or anions. 〔Aspect 8〕 The battery according to Aspect 7, wherein said separator selectively conducts anions. 〔Aspect 9〕 The battery according to Aspect 7, wherein said anion is a hydroxide anion. 〔Aspect 10〕 The battery according to Aspect 7, wherein said ion conductive polymer includes a hydroxide ion conductive membrane, and optionally, said hydroxide ion conductive membrane includes a support polymer bonded to an amine. 〔Aspect 11〕 The battery according to Aspect 7, wherein said ion conductive polymer includes a proton conductive membrane. 〔Aspect 12〕 The battery according to Aspect 11, wherein said proton conductive membrane includes a perfluorinated polymer, and optionally includes a perfluorosulfonic acid (PFSA) polymer. 〔Aspect 13〕 The battery according to Aspect 1, wherein said solid electrolyte is in the form of a membrane. 〔Aspect 14〕 In the battery according to Aspect 7, the ion-conductive polymer is coated on a solid ion-conductive substrate. 〔Aspect 15〕 In the battery according to Aspect 14, the ion-conductive substrate is Pt, Pd, LaNi 5 , or an oxide, optionally ZrO 2 or a perovskite oxide, or a combination thereof. 〔Aspect 16〕 In the battery according to Aspect 7, the ion-conductive polymer is embedded in a porous substrate, and optionally, the porous substrate has a porosity of 40% or more as the volume of voids defined as the volume of voids with respect to the total volume. 〔Aspect 17〕 In the battery according to Aspect 16, further, a layer of a proton or hydroxide ion-conductive polymer is included on one or both sides of the porous substrate. 〔Aspect 18〕 In the battery according to any one of Aspects 7 to 17, at least a part of the ion-conductive polymer further includes an ion-conductive organic powder. 〔Aspect 19〕 In the battery according to any one of Aspects 1 to 7, the Coulomb efficiency exceeds 70%, and optionally exceeds 80%. 〔Aspect 20〕 In the battery according to any one of Aspects 1 to 7, the negative electrode active material includes a hydrogen-absorbing metal or a hydrogen-absorbing metal alloy. 〔Aspect 21〕 In the battery according to Aspect 20, the metal alloy includes a metal alloy of an AB x type hydrogen storage material, where A is a hydride-forming element, B is a non-hydride-forming element, and x is 1 to 5. 〔Aspect 22〕 In the battery according to Aspect 20, the metal contains Si x M 1-x , where M contains one or more Group 14 elements other than Si, and 0 < x ≤ 1. 〔Aspect 23〕 In the battery according to any one of Aspects 1 to 7, the positive electrode active material includes Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, their hydrides, their oxides, their hydroxides, or any combination thereof. 〔Aspect 24〕 In the battery according to Aspect 23, the positive electrode active material contains Ni or Mn at 10 atomic percent or more, optionally 80 atomic percent or more, optionally 90 atomic percent or more with respect to all metals in the positive electrode electrochemically active material. 〔Aspect 25〕 In the battery according to Embodiment 23, the battery, wherein the positive electrode electrochemically active material contains a hydroxide of Ni, Co, Mn, Zn, Al, or a combination thereof. 〔Embodiment 26〕 In the battery according to Embodiment 23, the battery, wherein the positive electrode electrochemically active material contains Ni. 〔Embodiment 27〕 A bipolar battery including a plurality of stacked cells, wherein two or more of the cells a positive electrode including a positive electrode active material capable of reversibly absorbing hydrogen, the positive electrode active material being associated with a positive electrode substrate, a negative electrode including a negative electrode active material capable of reversibly absorbing hydrogen, the negative electrode active material being associated with a negative electrode substrate, a proton or hydroxide ion conducting separator between the positive electrode and the negative electrode, configured to selectively transport protons or hydroxide ions, and a separator configured as a film, as a component of a porous support membrane, or as a combination thereof, a bipolar metal plate associated with the negative electrode or the positive electrode, and a battery including the same. 〔Embodiment 28〕 In the battery according to Embodiment 27, the battery, wherein the separator selectively conducts anions. 〔Embodiment 29〕 In the battery according to Embodiment 27, the battery, wherein the anion is a hydroxide anion. 〔Embodiment 30〕 In the battery according to Embodiment 27, the battery, wherein the ion conductive polymer includes a proton conductive membrane. 〔Embodiment 31〕 In the battery according to Embodiment 30, the battery, wherein the proton conductive membrane includes a perfluorinated polymer and optionally a perfluorosulfonic acid (PFSA) polymer. 〔Embodiment 32〕 In the battery according to Embodiment 27, the battery, wherein the separator further includes one or more ion conductive inorganic powders. 〔Embodiment 33〕 In the battery according to Embodiment 27, the battery configured as a positive electrode capacity limited type. 〔Embodiment 34〕 In the battery according to any one of Embodiments 27 to 33, the battery, wherein the separator is in the form of a film and the film is not adhered to either the negative electrode or the positive electrode. 〔Embodiment 35〕 In the battery according to any one of Embodiments 27 to 33, the battery, wherein the separator is in the form of a coating on the negative electrode, the positive electrode, or both. 〔Embodiment 36〕 In the battery according to any one of aspects 27 to 33, the positive electrode is formed of a positive electrode active material attached to the positive electrode substrate, or the negative electrode is formed of a negative electrode active material attached to the negative electrode substrate, or both, the battery. 〔Aspect 37〕 In the battery according to any one of aspects 27 to 33, the negative electrode active material contains Si x M 1-x and M contains one or more Group 14 elements other than Si, and 0 < x ≤ 1, the battery. 〔Aspect 38〕 In the battery according to any one of aspects 27 to 33, the positive electrode active material contains an oxide, hydroxide, or oxyhydroxide of Ni or Mn in an amount of 10 atomic percent or more, optionally 80 atomic percent or more, and optionally 90 atomic percent or more based on all the metals in the positive electrode electrochemically active material, the battery. 〔Aspect 39〕 In the battery according to any one of aspects 27 to 33, the stable Coulombic efficiency after activation exceeds 70%, and optionally exceeds 80%, the battery being characterized by this.

Claims

1. A bipolar battery including a plurality of stacked cells, wherein two or more of said cells are a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, wherein the negative electrode active material includes Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, and the negative electrode, a proton-conductive polymer separator between said positive electrode and said negative electrode, a bipolar metal plate in electrical contact with said negative electrode or said positive electrode, an electrolyte including a solid polymer capable of conducting protons, and including a battery, wherein said separator is in the form of a coating on said negative electrode, said positive electrode, or both.

2. The battery according to claim 1, wherein said bipolar metal plate is in electrical contact with said positive electrode and said negative electrode.

3. A bipolar battery including a plurality of stacked cells, wherein two or more of said cells are a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, wherein the negative electrode active material includes Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, and the negative electrode, a proton-conductive polymer separator between said positive electrode and said negative electrode, a bipolar metal plate in electrical contact with said negative electrode or said positive electrode, an electrolyte including a solid polymer capable of conducting protons, and including a battery, wherein said separator is in the form of a film and said film is not adhered to either the negative electrode or the positive electrode.

4. The battery according to claim 1, wherein said positive electrode is formed by attaching a positive electrode active material to a positive electrode substrate, or said negative electrode is formed by attaching a negative electrode active material to a negative electrode substrate, or both.

5. The battery according to claim 4, wherein the positive electrode substrate, the negative electrode substrate, or both contain Ni foil.

6. The battery according to claim 1, wherein the separator selectively conducts cations.

7. The battery according to claim 6, wherein the proton-conductive polymer constituting the separator includes a proton-conductive membrane.

8. The battery according to claim 7, wherein the proton-conductive membrane includes a perfluorinated polymer.

9. A bipolar battery including a plurality of stacked cells, wherein two or more of the cells include a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, wherein the negative electrode active material includes Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, a proton-conductive polymer separator between the positive electrode and the negative electrode, a bipolar metal plate in electrical contact with the negative electrode or the positive electrode, an electrolyte including a solid polymer capable of conducting protons, and including the battery, wherein the electrolyte is in the form of a membrane.

10. A bipolar battery including a plurality of stacked cells, wherein two or more of the cells include a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, wherein the negative electrode active material includes Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, a proton-conductive polymer separator between the positive electrode and the negative electrode, a bipolar metal plate in electrical contact with the negative electrode or the positive electrode, an electrolyte including a solid polymer capable of conducting protons, comprising wherein the separator selectively conducts cations, a battery, wherein a proton-conductive polymer constituting the separator is coated on a solid ion-conductive substrate. **Claim 11** The battery according to claim 10, wherein the ion-conductive substrate comprises Pt, Pd, LaNi ５ , or an oxide, or a combination thereof. **Claim 12** A bipolar battery including a plurality of stacked cells, wherein two or more of the cells include a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, wherein the negative electrode active material comprises Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, a proton-conductive polymer separator between the positive electrode and the negative electrode, a bipolar metal plate in electrical contact with the negative electrode or the positive electrode, an electrolyte including a solid polymer capable of conducting protons, comprising wherein the separator selectively conducts cations, a battery, wherein a proton-conductive polymer constituting the separator is embedded in a porous substrate. **Claim 13** The battery according to claim 12, further comprising a layer of a proton-conductive polymer on one or both sides of the porous substrate. **Claim 14** The battery according to any one of claims 6 to 13, wherein the separator further comprises one or more ion-conductive organic powders. **Claim 15** The battery according to any one of claims 1 to 6, characterized in that the Coulomb efficiency exceeds 70%. **Claim 16** In the battery according to any one of claims 1 to 6, the battery, wherein the negative electrode active material contains a hydrogen-absorbing metal or a hydrogen-absorbing metal alloy.

17. In the battery according to claim 16, the battery, wherein the metal alloy contains a metal alloy of an AB ｘ type hydrogen storage material, where A is a hydride-forming element, B is a non-hydride-forming element, and x is 1 to 5.

18. In the battery according to claim 16, the battery, wherein the metal contains Si ｘ M １－ｘ and M contains one or more Group 14 elements other than Si, and 0 < x ≤ 1.

19. In the battery according to any one of claims 1 to 6, the battery, wherein the positive electrode active material contains Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, their hydrides, their oxides, their hydroxides, or any combination thereof.

20. In the battery according to claim 19, the battery, wherein the positive electrode active material contains Ni or Mn at 10 atomic percent or more based on all the metals in the positive electrode active material.

21. In the battery according to claim 19, the battery, wherein the positive electrode active material contains hydroxides of Ni, Co, Mn, Zn, Al, or a combination thereof.

22. In the battery according to claim 19, the battery, wherein the positive electrode active material contains Ni.

23. A bipolar battery including a plurality of stacked cells, wherein two or more of the cells include a positive electrode containing a positive electrode active material capable of reversibly absorbing hydrogen, and the positive electrode active material is supported on a positive electrode substrate. A negative electrode containing a negative electrode active material capable of reversibly absorbing hydrogen, wherein the negative electrode active material is supported on a negative electrode substrate, and the negative electrode active material contains Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, and a negative electrode; A proton-conducting separator between the positive electrode and the negative electrode, which contains a proton-conducting polymer, is configured to selectively transport protons, and is configured as a film, as a component of a porous support membrane, or as a combination thereof, and a separator; A bipolar metal plate in electrical contact with the negative electrode or the positive electrode; comprising; A battery, wherein the separator is in the form of a coating on the negative electrode, the positive electrode, or both.

24. A bipolar battery including a plurality of stacked cells, wherein two or more of the cells A positive electrode containing a positive electrode active material capable of reversibly absorbing hydrogen, wherein the positive electrode active material is supported on a positive electrode substrate, and a positive electrode; A negative electrode containing a negative electrode active material capable of reversibly absorbing hydrogen, wherein the negative electrode active material is supported on a negative electrode substrate, and the negative electrode active material contains Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof, and a negative electrode; A proton-conducting separator between the positive electrode and the negative electrode, which contains a proton-conducting polymer, is configured to selectively transport protons, and is configured as a film, as a component of a porous support membrane, or as a combination thereof, and a separator; A bipolar metal plate in electrical contact with the negative electrode or the positive electrode; comprising; A battery, wherein the proton-conducting polymer includes a proton-conducting membrane.

25. The battery according to claim 24, wherein the proton-conducting membrane contains a perfluorinated polymer.

26. The battery according to claim 23, wherein the separator further contains one or more kinds of ion-conductive inorganic powders.

27. The battery according to claim 23, which is configured as a positive electrode capacity-limited type.

28. A bipolar battery including a plurality of stacked cells, wherein two or more of the cells are a positive electrode including a positive electrode active material capable of reversibly absorbing hydrogen, wherein the positive electrode active material is supported on a positive electrode substrate; a negative electrode including a negative electrode active material capable of reversibly absorbing hydrogen, wherein the negative electrode active material is supported on a negative electrode substrate, and the negative electrode active material includes Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Au, Cd, or a combination thereof; a proton-conductive separator between the positive electrode and the negative electrode, including a proton-conductive polymer, configured to selectively transport protons, and configured as a film, as a component of a porous support membrane, or a combination thereof; a bipolar metal plate in electrical contact with the negative electrode or the positive electrode; and the separator is in the form of a film, and the film is not adhered to either the negative electrode or the positive electrode.

29. In the battery according to any one of claims 23 to 27, the positive electrode is formed of a positive electrode active material attached to the positive electrode substrate, or the negative electrode is formed of a negative electrode active material attached to the negative electrode substrate, or both.

30. In the battery according to any one of claims 23 to 27, the negative electrode active material contains Si ｘ M １－ｘ and includes, where M includes one or more Group 14 elements other than Si and 0 < x ≦ 1.

31. In the battery according to any one of claims 23 to 27, the positive electrode active material contains an oxide, hydroxide, or oxyhydroxide of Ni or Mn in an amount of 10 atomic percent or more based on all metals in the positive electrode active material.

32. In the battery according to any one of claims 23 to 27, the battery is characterized in that the stable Coulomb efficiency after activation exceeds 70%.

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