CN100568613C - Protected active metal electrodes and battery cell structures with non-aqueous interlayer construction - Google Patents

Abstract

Active metals and active metal intercalation electrode structures and battery cells with an ionically conductive protective structure comprising an active metal (e.g. The impregnated porous membrane is separated from the electrode (anode). This protective construction prevents adverse reactions of the active metal with the environment on the other (cathode) side of the impermeable layer, which may include an aqueous or non-aqueous liquid electrolyte (catholyte) and/or various electrochemically active materials, including Liquid, solid and gaseous oxidizers. Safety additives and manufacturing-friendly designs are also provided.

Description

Protected active metal electrodes and battery cell structures with non-aqueous interlayer construction

Background of the invention

1. Field of invention

The present invention generally relates to active metal electrochemical devices. More particularly, the present invention relates to active metal (e.g. alkali metals such as lithium), active metal intercalation (e.g. lithium-carbon, carbon) and active metal alloy (e.g. lithium-tin) alloys or alloyed metals (e.g. tin) electrochemical (eg electrodes) structures and battery cells. The electrode structure has an ionically conductive protective structure comprising an active metal (eg lithium) conductive water impermeable layer separated from the electrode (anode) by a porous separator impregnated with a non-aqueous electrolyte. This protective structure prevents unwanted reactions of the active metal with the environment on the other (cathode) side of the impermeable layer, which may include aqueous, air or organic liquid electrolytes and/or electrochemically active materials.

2. Description of related technologies

The low equivalent weight of alkali metals such as lithium makes them especially attractive as battery electrode components. Lithium can provide greater energy per volume than traditional battery standards - nickel and cadmium. Unfortunately, rechargeable lithium metal batteries have not been successful in the market.

The failure of rechargeable lithium metal batteries has largely been attributed to battery cycling issues. During repeated charge and discharge cycles, lithium "dendrites" gradually grow from the lithium metal electrode through the electrolyte and eventually contact the positive electrode. This causes an internal short circuit in the battery, rendering the battery unusable after a relatively few cycles. While cycling, lithium electrodes can also grow "spongy" deposits that dislodge from the negative electrode, thereby reducing battery capacity.

In order to solve the poor cycle performance of lithium in liquid electrolyte systems, some researchers proposed to apply a "protective layer" to the side of the lithium anode facing the electrolyte. This protective layer must conduct lithium ions, but at the same time prevent contact between the lithium electrode surface and the bulk electrolyte. Many techniques for applying layers of protection have been unsuccessful.

Some of the contemplated lithium metal protective layers are formed in situ by the reaction between lithium metal and compounds in the battery electrolyte in contact with lithium. Most of these in situ films are grown by controlled chemical reactions after the battery is assembled. Typically, such films have a porous morphology that allows partial electrolyte penetration onto the bare Li metal surface. Therefore, they cannot sufficiently protect lithium electrodes.

Various preformed lithium protective layers are also contemplated. For example, US Patent 5,314,765 (issued to Bates on May 24, 1994) describes an extrinsic technique for fabricating lithium electrodes comprising a thin layer of sputtered lithium oxynitride ("LiPON") or related materials. LiPON, a glassy single-ion conductor (conducting lithium ions), has been investigated as a possible electrolyte for solid-state lithium microbatteries fabricated on silicon and used in power integrated circuits (see US patents 5597660, 5567210, 5338625 and 5512147, all issued to Bates et al).

Work in the applicant's laboratory has developed techniques for using glassy or amorphous protective layers such as LiPON in active metal battery electrodes. (See, eg, U.S. Patents 6,025,094, issued 02/15/00, 6,402,795, issued 06/11/02, 6,214,061, issued 04/10/01, and 6,413,284, issued 07/02/02, all assigned to PolyPlus Battery, Inc.).

Existing efforts to use lithium anodes in aqueous environments rely on the use of strongly alkaline conditions such as the use of concentrated KOH aqueous solution to slow down Li electrode corrosion, or rely on the use of polymer coatings on Li electrodes to prevent water from diffusing to the Li electrode surface. superior. In all cases, however, there is substantial reaction of the alkali metal electrode with water. For this, the prior art teaches that it is not possible to use an aqueous cathode or electrolyte with a Li-metal anode, since the breakdown voltage of water is about 1.2V, a Li/water cell can have a voltage of about 3.0V. The direct contact between Li metal and aqueous solution leads to strong parasitic chemical reactions and corrosion of Li electrodes without any useful purpose. Research in the field of lithium metal batteries has therefore focused directly on the development of efficient non-aqueous (mostly organic) electrolyte systems.

Summary of the invention

The present invention generally relates to active metal electrochemical devices. More particularly, the present invention relates to active metal (e.g. alkali metals such as lithium), active metal intercalation (e.g. lithium-carbon, carbon) and active metal alloy (e.g. lithium-tin) alloys or alloyed metals (e.g. tin) electrochemical (eg electrodes) structures and battery cells. The electrode structure has an ionically conductive protective structure comprising an ionically conductive, substantially water-impermeable layer of an active metal (eg lithium), separated from the electrode (anode) by a porous membrane impregnated with a non-aqueous electrolyte (anolyte). This protective construction prevents detrimental reactions of the active metal with the environment on the other (cathode) side of the impermeable layer, which may include aqueous, air or organic liquid electrolytes (catholyte) and/or electrochemically active materials.

The separator layer (intermediate layer) of the protective construction prevents detrimental reactions between the active metal (eg lithium) of the anode and the active metal ion conductive substantially water impermeable layer. Thus, the configuration effectively isolates (separates) the anode/anolyte from the solvent, electrolyte handling, and/or cathode environment, including such environments that are typically highly corrosive to Li or other active metals, and simultaneously allows ion transport into and out of these potentially corrosive environments.

Various embodiments of the batteries and battery structures of the present invention include active metals, active metal ions, active metal alloying metals, and active metal intercalation anode materials protected by an ionically conductive protective construction with a non-aqueous anolyte. These anodes can be combined in battery cells with various possible cathode systems including water, air, metal hydride and metal oxide cathodes and associated catholyte systems, especially aqueous catholyte systems.

Safeguards can also be introduced into the structures and cells of the present invention in the event that the substantially impermeable layer of the protective structure (such as a glass or glass-ceramic membrane) breaks or otherwise breaks and allows the aggressive catholyte to enter and gain access to the lithium electrode. sexual additives. The non-aqueous interlayer structure may incorporate gelling/polymerizing agents that cause the formation of water-impermeable polymers on the lithium surface when in contact with the reactive catholyte. For example, the anolyte may include monomers of polymers that are insoluble or poorly soluble in water, such as dioxolane (Diox)/polydioxaloane, and the catholyte may include a polymerization initiator for the monomers , such as protonic acids.

Additionally, the structures and batteries of the present invention may take any suitable form. One advantageous form to facilitate manufacture is the tubular form.

In one aspect, the invention relates to electrochemical cell structures. The structure includes an anode composed of an active metal, active metal ion, active metal alloy, active metal alloyed metal, or active metal intercalation material. The anode has an ionically conductive protective structure on its surface. The construction includes an active metal ionically conductive membrane layer having a nonaqueous anolyte and chemically compatible with the active metal and contacting the anode, and a substantially water impermeable ionically conductive layer chemically compatible with the membrane layer and an aqueous environment and contacting the membrane layer. The separator layer may be a semipermeable membrane impregnated with an organic anolyte, such as a microporous polymer impregnated with a liquid or gel phase anolyte. Such electrochemical (electrode) structures can be paired with cathode systems, including aqueous cathode systems, to form battery cells according to the invention.

The structures of the invention and battery cells incorporating the structures of the invention can have a variety of configurations (including prismatic and cylindrical) and compositions, including active metal ions, alloys and intercalated anodes, aqueous, water, air, metal hydride and Metal oxide cathodes, and aqueous, organic or ionic liquid catholytes; electrolyte (anolyte and/or catholyte) assemblies and components that enhance battery safety and/or performance; and manufacturing techniques.

These and other features of the present invention are further described and enumerated in the detailed description below.

Brief description of the drawings

Figure 1 is a schematic diagram of an electrochemical structural cell incorporating an ion-conducting protective interlayer construction according to the present invention.

Figure 2 is a schematic illustration of a battery cell incorporating an ionically conductive protective interlayer construction according to the present invention.

3A-C illustrate an embodiment of a battery cell using a tubular guarded anode design according to the present invention.

4-7 are graphs of data illustrating the performance of various cells incorporating ionically conductive protective interlayer configurations of the present invention.

FIG. 8 illustrates a test cell for testing various Li foil thicknesses in the aqueous electrolyte used to generate the data shown in FIG. 7 .

Fig. 9 is the battery specific energy estimation curve of the anode combined with the ion-conducting protective interlayer structure of the present invention with different thicknesses, the battery weight specific energy value of the protected anode with a Li thickness of 3.3mm, the battery structure illustration and the parameters used for calculation .

Figure 10 illustrates a hydrogen generator for Li/water batteries and fuel cells according to one embodiment of the present invention.

Detailed description of the specific implementation plan

Specific embodiments of the present invention will now be described in detail. Examples of specific embodiments are illustrated in the accompanying drawings. While the invention has been described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to such specific embodiments. On the contrary, it is intended to cover alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.

When used in conjunction with "comprises", "a method comprising", "a means comprising" or similar language in this specification and the appended claims, the singular forms "a" and "the" include plural referents unless the context clearly dictates otherwise specified. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

introduction

Active metals are highly reactive under ambient air conditions and benefit from barrier layers when used as electrodes. These are typically alkali metals such as (eg, lithium, sodium, or potassium), alkaline earth metals (eg, calcium or magnesium), and/or certain transition metals (eg, zinc), and/or alloys of two or more of these. The following active metals can be used: alkali metals (e.g. Li, Na, K), alkaline earth metals (e.g. Ca, Mg, Ba) or dioxos with Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, In elemental or ternary alkali metal alloys. Preferred alloys include lithium aluminum alloys, lithium silicon alloys, lithium tin alloys, lithium silver alloys, and sodium lead alloys (eg _Na4Pb ). A preferred active metal electrode consists of lithium.

The low equivalent weight of alkali metals such as lithium makes them especially attractive as battery electrode components. Lithium can provide greater energy per unit volume than traditional battery standards - nickel and cadmium. However, lithium metal or compounds that incorporate lithium at potentials close to that of lithium metal (e.g., within about 1 volt), such as lithium alloys and lithium-ion (lithium intercalation) anode materials, are potentially attractive electrolytes and cathodes for many The material is highly reactive. The present invention describes the use of a non-aqueous electrolyte interlayer construction to isolate an active metal (e.g. alkali metal, such as lithium), active metal alloy, or active metal ion electrode (typically the anode of a battery cell) from the surrounding environment and/or the cathode of the cell side. The configuration includes an active metal ion conducting membrane layer having a non-aqueous anolyte (i.e., the electrolyte surrounding the anode) that is chemically compatible with the active metal and in contact with the anode, and a membrane layer that is chemically compatible with the membrane layer and the aqueous environment and The substantially water-impermeable ionically conductive layer contacts the membrane layer. The non-aqueous electrolyte interlayer configuration effectively isolates (separates) the anode from the surrounding environment and/or the cathode, including the catholyte (i.e., the electrolyte surrounding the cathode) environment, including such environments that are generally highly corrosive to Li or other active metals , and at the same time allow ion transfer into and out of these potentially corrosive environments. In this way, there is great flexibility in allowing other components of an electrochemical device, such as a battery cell, to be made with this configuration. Isolation of the anode from the other components of the battery or other electrochemical cell in this manner allows the use of virtually any solvent, electrolyte, and/or cathode material in conjunction with the anode. Furthermore, optimization of the electrolyte or cathode-side solvent system can be performed without compromising anode stability or performance.

There are many potentials that can benefit from the use of aqueous solutions, air, and other materials on the cathode side of a battery with an active metal (e.g., an alkali metal, such as lithium) or on the anode with an active metal intercalation (e.g., lithium alloy or lithium-ion) in a battery cell. Applications, aqueous solutions include water and water-based electrolytes, other materials reactive to lithium and other active metals, including organic solvents/electrolytes and ionic liquids.

The use of lithium intercalation electrode materials such as lithium-carbon and lithium alloy anodes rather than lithium metal for the anode may also provide beneficial battery characteristics. First, it allows the achievement of extended battery cycle life without the risk of forming lithium metal dendrites that can grow from the Li surface to the membrane surface causing membrane damage. Moreover, in some embodiments of the present invention, the use of lithium-carbon and lithium alloy anodes instead of lithium metal anodes can significantly improve battery safety because it avoids the formation of highly reactive "sponge" lithium during cycling.

The present invention describes protected active metals, alloys or intercalation electrodes that enable very high energy density lithium batteries, such as those using aqueous or other electrolytes that would otherwise react adversely with, for example, lithium metal. Examples of these high energy battery pairs are lithium-air, lithium-water, lithium-metal hydride, lithium-metal oxide, and lithium alloy and lithium-ion variants of these. Batteries of the present invention may incorporate other components in their electrolytes (anolyte and catholyte) to enhance battery safety, and may have a variety of configurations, including planar and tubular/cylindrical.

Non-aqueous middle layer structure

The non-aqueous interlayer construction of the present invention is provided in an electrochemical cell structure having an anode and an ionically conductive protective construction on a first surface of the anode, the anode being composed of an active metal, an active metal ion, an active metal alloy, an active metal Alloyed and active metal embedded in material composition. The construction consists of an active metal ion-conducting membrane layer with a non-aqueous anolyte and a substantially water-impermeable ion-conducting layer that is chemically compatible with the active metal and contacts the anode and an ionically-conducting layer that is chemically compatible with the membrane layer and the aqueous environment and contact the membrane layer. The separator layer may comprise a semipermeable membrane such as a microporous polymer such as available from Celgard, Inc. Charlotte, North Carolina, impregnated with an organic anolyte.

The protective construction of the present invention incorporates a substantially water-impermeable layer of an active metal ion conducting glass or glass-ceramic, such as a lithium ion conducting glass-ceramic (LIC-GC), which has high active metal ion conductivity and a Stability of aggressive electrolytes with strong metal reactions such as aqueous electrolytes. Suitable materials are substantially water-impermeable, ionically conductive, and chemically compatible with aqueous electrolytes or other electrolytes (catholytes) and/or cathode materials that otherwise react unfavorably with, for example, lithium metal. Such glass or glass-ceramic materials are substantially gapless, non-swellable and ionically conductive in nature. That is, they do not rely on the presence of liquid electrolytes or other reagents due to their inherent ionically conductive properties. They also have a high ionic conductivity of at least 10 ^-7 S/cm, usually at least 10 ^-6 S/cm, for example at least 10 ^{- 5} S/cm-10 ^-4 S/cm, and up to 10 ^-3 S/cm cm or higher, so that the overall ionic conductivity of the multilayer protective structure is at least 10 ⁻⁷ S/cm and as high as 10 ⁻³ S/cm or higher. The thickness of the layer is preferably about 0.1-1000 microns, or when the ionic conductivity of the layer is about ^10-7 S/cm, about 0.25-1 micron, or when the ionic conductivity of the layer is between about ^10-4 and about Between 10 ⁻³ S/cm, about 10-1000 microns, preferably between 1 and 500 microns, more preferably between 10 and 100 microns, eg 20 microns.

Suitable examples of suitable substantially impermeable lithium ion conducting layers include glassy or amorphous metal ion conductors such as phosphorus-based glasses, oxide-based glasses, phosphorus-oxynitride-based glasses, sulfur (sulpher)-based glasses, oxide /Sulphide-based glass, Selenide-based glass, Gallium-based glass, Germanium-based glass or Peroborite glass (such as DPButton et al. in Solid State Ionics, Volume 9-10, Part 1, 585-592 (December 1983) described in ); ceramic active metal ion conductors, such as lithium β-alumina, sodium β-alumina, Li superionic conductor (LISICON), Na superionic conductor (NASICON), etc.; or glass-ceramic active metal ion conductors. Specific examples include LiPON, Li ₃ PO ₄ .Li ₂ S.SiS ₂ , Li ₂ S.GeS ₂ .Ga ₂ S ₃ , Li ₂ O·11Al ₂ O ₃ , Na ₂ O·11Al ₂ O ₃ , (Na, Li) _1+x Ti _2-x Al _x (PO ₄ ) ₃ (0.6≤x≤0.9) and crystallographically related structures, Na ₃ Zr ₂ Si ₂ PO ₁₂ , Li ₃ Zr ₂ Si ₂ PO ₁₂ , Na ₅ ZrP ₃ O ₁₂ , Na ₅ TiP ₃ O ₁₂ , Na ₃ Fe ₂ P ₃ O ₁₂ , Na ₄ NbP ₃ O ₁₂ , Li ₅ ZrP ₃ O ₁₂ , Li ₅ TiP ₃ O ₁₂ , Li ₃ Fe ₂ P ₃ O ₁₂ and Li ₄ NbP ₃ O ₁₂ , and combinations thereof, are optionally sintered or melted. Suitable ceramic ionically active metal ion conductors are described, for example, in Adachi et al., US Patent 4,985,317, which is incorporated herein by reference in its entirety for all purposes.

A particularly suitable glass-ceramic material for the substantially water-impermeable layer of the protective construction is one having the following composition and comprising Li _1+x (M, Al, Ga) _x (Ge _1-y Ti _y ) _2-x (PO ₄ ) ₃ and/or Li _1+x+y Q _x Ti _{2- x} Si _y P _3-y O ₁₂ main crystal phase Li-ion conductive glass-ceramics:

Where X≤0.8 and 0≤Y≤1.0 in Li _1+x (M, Al, Ga) _x (Ge _1-y Ti _y ) _2-x (PO ₄ ) ₃ , M is selected from Nd, Sm, Eu, Elements of Gd, Tb, Dy, Ho, Er, Tm and Yb, Li _1+x+y Q _x Ti _2-x Si _y P _3-y O ₁₂ in 0<X≤0.4 and 0<Y≤0.6, Q It is Al or Ga. Glass-ceramics are obtained by melting raw materials into a melt, casting the melt into glass, and heat-treating the glass. Such materials are available from OHARA Corporation of Japan and are further described in US Patent Nos. 5,702,995, 6,030,909, 6,315,881 and 6,485,622, incorporated herein by reference.

Such lithium-ion conductive substantially impermeable layers and their fabrication techniques and incorporation in battery cells are described in U.S. Provisional Patent Application No. 60/418899, filed October 15, 2002, and entitled IONICALLY CONDUCTIVE COMPOSITESFOR PROTECTION OF ANODES AND ELECTROLYTES, its corresponding U.S. patent application No. 10/686189 (Attorney Docket No.PLUSP027), submitted on October 14, 2003, titled IONICALLY CONDUCTIVE COMPOSITES FOR PROTECTION OF ACTIVE METAL ANODES, U.S. patent application No. .10/731771 (Attorney Docket No.PLUSP027X1), filed December 5, 2003, entitled IONICALLY CONDUCTIVE COMPOSITES FORPROTECTION OF ACTIVE METAL ANODES, and U.S. Patent Application No. 10/772228 (Attorney Docket No.PLUSP039), 2004 Submitted on February 3, the title is IONICALLY CONDUCTIVE MEMBRANES FORPROTECTION OF ACTIVE METAL ANODES AND BATTERYCELLS. These applications are incorporated herein by reference in their entirety for all purposes.

A critical limitation when using these strongly conductive glasses and glass-ceramics in lithium (or other active metal or active metal intercalation) batteries is their sensitivity to lithium metal or bound lithium at potentials close to that of lithium metal (e.g., within about 1 volt). Compound reactivity. The non-aqueous electrolyte interlayer of the present invention isolates the lithium (for example) electrode from reacting with the glass or glass-ceramic membrane. The non-aqueous interlayer can have a semi-permeable membrane, such as a Celgard microporous separator, to prevent the lithium electrode from mechanically contacting the glass or glass-ceramic membrane. The membrane is impregnated with an organic liquid electrolyte (anolyte) with a solvent such as ethylene carbonate (EC), propylene carbonate (PC), 1,2-dimethoxyethane (DME), 1 , 3-dioxolane (DIOX), or various ethers, glyme, lactone, sulfone, sulfolane, or mixtures thereof. It may also or alternatively have a polymer electrolyte, a gel-type electrolyte, or a combination of these. Important criteria are that the lithium electrode is stable in the nonaqueous anolyte, that the nonaqueous anolyte is sufficiently conductive for Li+ ions, that the lithium electrode is not in direct contact with the glass or glass-ceramic membrane, and that the entire device allows lithium ions to pass through the glass or glass-ceramic membrane. Ceramic Membrane.

Referring to Figure 1, a specific embodiment of the present invention is illustrated and described. 1 shows a not-to-scale view of an electrochemical cell structure 100 having an active metal, active metal ion, active metal alloying metal, or active metal intercalation material anode 102 and an ionically conductive protective construction 104 . The protective construction 104 has an active metal ion-conducting membrane layer 106 with a non-aqueous anolyte (also sometimes referred to as a transfer electrolyte) on the surface of the anode 102 and a substantially water-impermeable ion-conducting layer 108 contacting the membrane layer 106 . The membrane layer 106 is chemically compatible with the active metal, and the substantially water-impermeable layer 108 is chemically compatible with the membrane layer 106 and the aqueous environment. The structure 100 may optionally include a current collector 110 composed of a suitable conductive metal that does not alloy with or embed the active metal. When the active metal is lithium, a suitable current collector material is copper. The current collector 110 can also be used to seal the anode from the surrounding environment to prevent adverse reactions of the active metal with the surrounding air or moisture.

The membrane layer 106 consists of a semipermeable membrane impregnated with an organic anolyte. For example, the semipermeable membrane can be a microporous polymer such as available from Celgard, Inc. The organic anolyte can be in liquid or gel phase. For example, the anolyte may include solvents selected from organic carbonates, ethers, lactones, sulfones, etc., and combinations thereof, such as EC, PC, DEC, DMC, EMC, 1,2-DME, or higher glyme ethers, THF, 2MeTHF, sulfolane, and combinations thereof. 1,3-Dioxolane can also be used as an anolyte solvent, especially, but not necessarily, to enhance the safety of batteries incorporating this structure, as described further below. When the anolyte solution is in the gel phase, a gelling agent such as polyvinylidene fluoride (PVdF) compound, hexafluoropropylene-vinylidene fluoride copolymer (PVdf-HFP), polyacrylonitrile compound, cross-linked polyether can be added Compounds, polyoxyalkylene compounds, polyoxyethylene compounds, combinations, etc., to form a gel from a solvent. Of course, suitable anolytes also include active metal salts, as in the case of lithium, for example LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSO ₃ CF ₃ or LiN(SO ₂ C ₂ F ₅ ) ₂ . An example of a suitable separator layer is 1M LiPF6 dissolved in propylene carbonate and impregnated in a Celgard microporous polymer membrane.

The protective construction according to the invention has numerous advantages. Especially battery structures incorporating this configuration are easier to manufacture. In one example, lithium metal is simply placed against a microporous separator impregnated with an organic liquid or gel electrolyte, which is next to a glass/glass-ceramic active metal ion conductor.

Additional advantages of non-aqueous interlayers are achieved when glass-ceramic is used. When heat treating amorphous glass of the type described in the OHARA Corporation patent cited above, the glass devitrifies, resulting in the formation of a glass-ceramic. However, such heat treatment can lead to the formation of surface roughness, which is difficult to coat by vapor deposition of inorganic protective interlayers such as LiPON, _Cu3N , etc. The use of a liquid (or gel) non-aqueous electrolyte interlayer can easily cover such a rough surface by conventional liquid flow, thereby eliminating the need for surface polishing and the like. In this sense, techniques such as "shrinkage" (described by Sony Corporation and Shott Glass (T. Kessler, H. Wegener, T. Togawa, M. Hayashi and T. Kakizaki, "Large Microsheet Glass for 40-in. Class PALC Displays", 1997, FMC2-3, downloaded from the Shott Glass website: http://www.schott.com/english, incorporated herein by reference)) to form thin glass layers (20-100 microns), and heat treat these The glass forms a glass-ceramic.

battery pack battery

Non-aqueous interlayer constructions are generally employed effectively in battery cells. For example, the electrochemical structure 100 of FIG. 1 can be paired with the cathode system 120 to form a battery 200, as shown in FIG. 2 . Cathode system 120 includes electronically conductive components, ionically conductive components, and electrochemically active components. Due to the isolation provided by the protective structure, the cathode system 120 can be of any desired composition, independent of the composition of the anode or anolyte. In particular, the cathodic system may incorporate components that would otherwise be strongly reactive with the anode active metal, such as aqueous materials, including water, aqueous catholyte and air, metal hydride electrodes and metal oxide electrodes.

In one embodiment, a Celgard separator will be placed against one side of the thin glass-ceramic, followed by a non-aqueous liquid or gel electrolyte, followed by a lithium electrode. On the other side of the glass-ceramic membrane, aggressive solvents such as aqueous electrolytes can be used. In this way, for example inexpensive Li/water or Li/air batteries can be constructed.

Batteries according to the invention can have very high capacities and specific energies. For example, batteries with capacities greater than 5, greater than 10, greater than 100, or even greater than 500 mAh/ ^cm2 are possible. As further described in the Examples below, a Li/water test cell of the invention with a Li anode about 3.35 mm thick was demonstrated to have a capacity of about 650 mAh/ ^cm2 . Based on this performance, it is presumed that the Li/air battery of the present invention exhibits a very high specific energy. For example, for a Li/air battery with a 3.3 mm thick Li anode, a stack thickness of 6 mm and an area of 45 ^cm2 , the specific energy is about 3400 Wh/l (4100 Wh/kg) unencapsulated and about 1000 Wh/kg when encapsulated. l (1200Wh/kg), assuming 70% package load.

Cathode system

As noted above, due to the isolation provided by the protective construction, the cathode system 120 of a battery cell according to the present invention may be of any desired composition, independent of the anode or anolyte composition. In particular, the cathode system may incorporate components that would otherwise be strongly reactive with the anode active metal, such as aqueous materials, including water, aqueous solutions and air, metal hydride electrodes and metal oxide electrodes.

The battery cells of the present invention may include, without limitation, water, aqueous solution, air electrodes, and metal hydride electrodes, as described in co-pending application Ser. For reference and for various purposes, as well as metal oxide electrodes, such as those used in conventional lithium-ion batteries.

The effective isolation between anode and cathode achieved by the protective interlayer configuration of the invention also enables great flexibility in the choice of cathode systems, especially aqueous systems as well as non-aqueous systems. Since the protected anode is completely separated from the catholyte, the compatibility of the catholyte with the anode is no longer an issue, and solvents and salts that are kinetically unstable to Li can be used.

For batteries using water as the electrochemically active cathode material, the porous electronically conductive support structure can provide the electronically conductive component of the cathode system. The aqueous electrolyte (catholyte) provides the ionophore for Li ion transport (conductivity) and the anions that bind Li. The electrochemically active component (water) and the ionically conductive component (aqueous catholyte) will be mixed into a single solution, although they are conceptually separate elements of the battery cell. Suitable catholytes for Li/water battery cells of the present invention include any aqueous electrolyte with suitable ionic conductivity. Suitable electrolytes may be acidic, such as strong acids such as HCl, _{H2SO4 , H3PO4} or weak acids such as acetic acid/lithium acetate; basic, such as LiOH; neutral, such as _seawater , LiCl, LiBr, LiI; or amphoteric, For example, NH ₄ Cl, NH ₄ Br, etc.

The suitability of seawater as an electrolyte enables battery cells with very high energy densities for marine applications. Before use, the cell structure consists of a protected anode and a porous electronically conductive support structure (the electronically conductive part of the cathode). When required, the cell is completed by submerging the cell in seawater which provides electrochemically active and ionically conductive components. Since the latter component is provided by seawater in the environment, it is not shipped as part of the battery cell (and thus does not need to be included in the battery energy density calculation) until it is used. Such cells are referred to as "open circuit" cells because no reaction products on the cathode side are contained. Therefore, this battery is a primary battery.

Secondary Li/water batteries are also possible according to the invention. As noted above, such cells are referred to as "closed-circuit" cells because the reaction products on the cathode side of the cell are contained on the cathode side, which serve to move Li across the protective membrane when a suitable recharging potential is applied to the cell. The ions return to recharge the anode.

As described above and further below, in another embodiment of the present invention, the ionomer coated on the porous catalytic electronically conductive support reduces or eliminates the need for ionic conductivity in the electrochemically active material.

The electrochemical reactions occurring in Li/water batteries are redox reactions in which the electrochemically active cathode material is reduced. In Li/water batteries, catalytic electron-conducting supports facilitate redox reactions. As mentioned above, but not limited thereto, in a Li/water battery, the battery reaction is considered to be:

Li+H ₂ O=LiOH+1/2H ₂

The half-cell reactions at the anode and cathode are considered to be:

Anode: Li＝Li ⁺ +e ^-

Cathode: e ^- +H ₂ O=OH ^- +1/2H ₂

Therefore, the catalyst of the Li/water cathode facilitates the electron transfer to water, generating hydrogen and hydroxide ions. A common inexpensive catalyst for this reaction is nickel metal; noble metals such as Pt, Pd, Ru, Au, etc. also work but are more expensive.

Batteries with protected Li anodes and aqueous electrolytes are also contemplated within the scope of the Li (or other active metal)/water batteries of the present invention, wherein the aqueous electrolyte is composed of water-soluble materials that can be used as active cathode materials (electrochemically active Components) gaseous and/or solid oxidant composition. The use of water-soluble compounds that are stronger oxidants than water can significantly increase battery energy in some applications compared to lithium/water batteries where electrochemical hydrogen evolution occurs at the cathode surface during the battery discharge reaction. Examples of such gaseous oxidants are _O2 , _SO2 and _NO2 . In addition, metal nitrites, _{especially NaNO2} and _KNO2 , and metal sulfites such as _Na2SO3 and _K2SO3 are stronger oxidizing agents than water and can be easily dissolved in large concentrations _. Another class of inorganic oxidizing agents that are soluble in water are lithium, sodium and potassium peroxides, and hydrogen peroxide _{H2O2 .}

It is especially advantageous to use hydrogen peroxide as oxidizing agent. There are at least two ways of using hydrogen peroxide in a battery cell according to the invention. First, the chemical decomposition of hydrogen peroxide on the cathode surface results in the generation of oxygen, which can be used as an active cathode material. The second, and perhaps more efficient method, is based on the direct electroreduction of hydrogen peroxide on the surface of the cathode. In principle, hydrogen peroxide can be reduced from alkaline or acidic solutions. The highest energy densities are obtained for cells utilizing hydrogen peroxide reduction in acidic solutions. In this case, the cell with Li anode yielded E ⁰ =4.82 V (standard conditions) compared to E ⁰ =3.05 V for the Li/water pair. However, due to the very high reactivity of the two acids and hydrogen peroxide towards unprotected Li, such cells are practically only achievable with protected Li anodes such as those according to the present invention.

For cells that use air as the electrochemically active cathode material, the electrochemically active components of air for these cells include moisture that provides water for the electrochemical reaction. The battery has an electronically conductive support structure electrically connected to the anode to allow electron transfer to reduce the air cathode active material. The electronically conductive support structure is typically porous to allow fluid (air) flow and is catalytic or treated with a catalyst to catalyze the reduction of the cathode active material. An aqueous electrolyte or ionomer with suitable ionic conductivity is also in contact with the electronically conductive support structure to allow ion transport within the electronically conductive support structure to complete the redox reaction.

An air cathode system includes an electronically conductive component (eg, a porous electronic conductor), an ionically conductive component having at least one aqueous component, and air as the electrochemically active component. It can be any suitable air electrode, including those commonly used in metal (eg Zn)/air cells or low temperature (eg PEM) fuel cells. Air cathodes used in metal/air batteries, especially Zn/air batteries, are described in many sources, including "Handbook of Batteries" (Linden and TBReddy, McGraw-Hill, NY, 3rd ed.), and typically consist of several layers , including air diffusion membranes, hydrophobic Teflon layers, catalyst layers, and metal electronically conductive components/current collectors, such as Ni sieves. The catalyst layer also includes an ionically conductive component/electrolyte which may be aqueous and/or ionomeric. A typical aqueous electrolyte consists of KOH dissolved in water. Typical ionolytic electrolytes consist of hydrated (water) Li ion-conducting polymers such as perfluorosulfonic acid polymer membranes (eg du Pont NAFION). Air diffusion membranes regulate air (oxygen) flow. The hydrophobic layer prevents the battery's electrolyte from penetrating into the air diffusion membrane. This layer usually contains carbon and Teflon particles. The catalyst layer typically contains high surface area carbon and a catalyst that accelerates oxygen reduction. In most commercial cathodes, metal oxides such as _MnO2 are used as catalysts for oxygen reduction. Alternative catalysts include metal macrocycles such as cobalt phthalocyanine, and highly dispersed noble metals such as platinum and platinum/ruthenium alloys. Since the air electrode structure is chemically isolated from the active metal electrode, the chemical composition of the air electrode is not limited by the possible reactivity with the anode active material. This allows the design of higher performance air electrodes using materials that would normally attack unprotected metal electrodes.

Another type of active metal/aqueous battery cell incorporating a protected anode and cathode system according to the invention is a lithium (or other active metal)/metal hydride cell. For example, a lithium anode protected with the non-aqueous interlayer configuration described herein can be discharged and charged in an aqueous solution suitable as an electrolyte in a lithium/metal hydride cell. A suitable electrolyte provides the source or protons. Examples include halide acids or acid salts, including aqueous solutions of chloride or bromide acids or salts such as HCl, HBr, _NH4Cl or _NH4Br .

In addition to the above systems containing water, air, etc., improved performance can be obtained by using cathode systems that combine conventional Li-ion battery cathodes and electrolytes, such as metal oxide cathodes (such as Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ and LiFePO ₄ ) and binary, ternary or multicomponent mixtures of alkyl carbonates, or their mixtures with ethers as solvents for Li metal salts (such as LiPF ₆ , LiAsF ₆ or LiBF ₄ ); or Li metal battery cathodes (e.g. elemental sulfur or polysulfides) and electrolytes consisting of organic carbonates, ethers, glymes, lactones, sulfones, sulfolanes, and combinations thereof, such as EC, PC, DEC, DMC , EMC, 1,2-DME, THF, 2MeTHF, and combinations thereof, as described, for example, in US Patent 6,376,123, incorporated herein by reference.

Furthermore, the catholyte solution can consist only of low viscosity solvents such as ethers like 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,3-dioxolane Cyclo(DIOX), 4-methyldioxolane (4-MeDIOX) or organic carbonates such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) or their mixture. Alternatively, ultra-low viscosity ester solvents or co-solvents such as methyl formate and methyl acetate, which are very reactive towards unprotected Li, can be used. Those skilled in the art are aware that ionic conductivity and diffusion rate are inversely proportional to viscosity such that, all other things being equal, cell performance increases as solvent viscosity decreases. The use of this catholyte solvent system significantly improves battery performance, especially discharge and charge characteristics at low temperatures.

Ionic liquids may also be used in the catholyte of the present invention. Ionic liquids are organic salts with melting points below 100°C, often even below room temperature. The most commonly used ionic liquids are imidazolium and pyridinium derivatives, but phosphonium or tetraalkylammonium compounds are also known. Ionic liquids have desirable properties of high ionic conductivity, high thermal stability, no measurable vapor pressure, and non-flammability. Representative ionic liquids are 1-ethyl-3-methylimidazolium tosylate (EMIM-Ts), 1-butyl-3-methylimidazolium octyl sulfate (BMIM-OctSO4), 1- Ethyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium tetrafluoroborate. Despite great interest in ionic liquids for electrochemical applications such as capacitors and batteries, they are unstable towards metallic lithium and lithiated carbon. However, the protected lithium anode described in the present invention is isolated from the direct chemical reaction, thus lithium metal batteries using ionic liquids can be used as an embodiment of the present invention. Such batteries should be particularly stable at high temperatures.

safety additives

As a safety measure, the non-aqueous interlayer construction may incorporate gelling/polymerizing agents that can lead to the formation of a water-impermeable polymer on the surface of the anode (eg, lithium) when in contact with a reactive electrolyte (eg, water). This safety measure serves to protect the construction's substantially impermeable layers (such as glass or glass-ceramic membranes) from cracking or otherwise becoming damaged and allowing aggressive catholyte to enter and reach the lithium electrode thereby increasing the Li anode and aqueous catholyte. Situations where strong reactions are possible.

By providing insoluble or little water soluble polymer monomers such as dioxolane (Diox) in the anolyte (e.g. in an amount of about 5-20% by volume) and in the catholyte with monomers Initiators such as protic acids prevent this reaction. Diox-based anolytes can be composed of organic carbonates (EC, PC, DEC, DMC, EMC), ethers (1,2-DME, THF, 2MeTHF, 1,3-dioxolane and some others) and mixtures thereof . Anolytes comprising dioxolane as the main solvent (e.g. 50-100% by volume) and Li salts, especially LiAsF ₆ , LiBF ₄ , LiSO ₃ CF ₃ , LiN(SO ₂ C ₂ F ₅ ) ₂ are particularly attractive . Diox is a good passivator for Li surfaces and good cycling data for Li metal have been obtained in Diox based electrolytes (see eg US Patent 5506068). In addition to its compatibility with Li metal, Diox combined with the aforementioned ionic salts forms a strongly conductive electrolyte. The corresponding aqueous catholyte comprises a Diox polymerization initiator capable of producing a Diox polymerization product (polydioxolane) which is insoluble or only slightly soluble in water.

If the membrane is damaged, the catholyte containing dissolved initiator is in direct contact with the Diox-based anolyte and polymerization of Diox occurs against the Li anode surface. Polydioxolane, a product of Diox polymerization, has high electrical resistance, so the battery stops working. Additionally, the formed polydioxolane layer serves as a barrier layer to prevent the reaction between the Li surface and the aqueous catholyte. Diox can be polymerized by protic acid dissolved in the catholyte. Furthermore, water-soluble Lewis acids, especially the benbenzoyl cation, can be used for this purpose.

Thus, improvements in cycleability and safety can be achieved by using a dioxolane (Diox)-based anolyte and a catholyte containing a Diox polymerization initiator.

Active Metal Ion and Alloy Anodes

The present invention relates to batteries and other electrochemical structures having an anode composed of an active metal as described above. A preferred active metal electrode consists of lithium (Li). Suitable anolytes for these structures and cells are described above.

The present invention also relates to electrochemical structures with active metal ion (eg lithium-carbon) or active metal alloy (eg Li-Sn) anodes. Some structures may initially have an uncharged active metal ion intercalation material (such as carbon) or an alloying metal (such as tin (Sn)) that is subsequently charged by the active metal or active metal ions. Although the present invention is applicable to various active metals, it is mainly described herein in conjunction with lithium as an example.

Carbon materials commonly used in conventional Li-ion batteries, especially petroleum coke and mesocarbon microsphere carbon, can be used as anode materials in Li-ion aqueous battery cells. Lithium alloys including one or more metals selected from Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, In, and Sb, preferably Al, Sn, or Si, can also be used as the lithium alloy of this battery. anode material. In a specific embodiment, the anode includes Li, Cu and Sn.

Anolytes of this structure can incorporate supporting salts, for example, dissolved in binary or ternary mixtures of non-aqueous solvents commonly used in conventional Li-ion batteries such as EC, PC, DEC, DMC, EMC, MA, MF LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiSO ₃ CF ₃ , LiN(CF ₃ SO ₂ ) ₂ or LiN(SO ₂ C ₂ F ₅ ) ₂ . Gel-polymer electrolytes can also be used, for example comprising one of the salts mentioned above, a polymer binder such as PVdF, PVdF-HFP copolymer, PAN or PEO, and a plasticizer (solvent) such as EC, PC, DEC, DMC , EMC, THF, 2MeTHF, 1,2-DME and their mixture electrolyte.

For cells using these anodes, suitable cathode structures can be added to the electrochemical structures on the other side of the protective construction. This configuration enables Li-ion type batteries using a large number of special cathodes such as air, water, metal hydrides or metal oxides. For Li-ion aqueous battery cells, for example, the aqueous catholyte may be alkaline, acidic, or neutral and contain Li cations. An example of a suitable aqueous catholyte is 2M LiCl, 1M HCl.

During the first charge of a battery with a lithium-carbon lithium alloy anode, Li cations are transferred from the catholyte through the protective structure (including the anolyte) to the anode surface, where the intercalation process occurs as in conventional Li-ion batteries. In one embodiment, the anode is chemically or electrochemically lithiated externally prior to cell assembly.

battery design

Electrochemical structures and battery cells according to the invention may have any suitable geometry. For example, considering the description provided herein of a structure or cell component obtained by stacking planar layers of the various components (anode, intermediate layer, cathode, etc.) of the structure or cell according to known battery cell fabrication techniques readily adapted to the present invention Flat geometric shapes. These stacked layers can be designed as prismatic structures or batteries.

Alternatively, the use of tubular glass or glass-ceramic electrolytes with non-aqueous interlayer configurations allows the construction of high surface area anodes with small sealing areas. In contrast to flat plate designs where the length of the seal increases with the surface area of the cell, tubular structures utilize end seals where the length of the tube can be increased to increase the surface area without changing the seal area. This allows the construction of high surface area Li/water and Li/air batteries that should have correspondingly high power densities.

The use of the non-aqueous midlayer construction of the present invention facilitates construction. Open-ended (with seals) or closed-ended glass or glass-ceramic (i.e., substantially water-impermeable active metal-ion-conducting solid electrolyte) tube sections filled with a non-aqueous organic electrolyte (anolyte or transfer electrolyte) as described above, such as for general use Electrolyte in lithium primary batteries. A lithium metal rod with a current collector surrounded by some type of physical membrane (eg semi-permeable polymer membrane such as Celgard, Tonin, polypropylene mesh, etc.) is inserted into the tube. Physically separate the lithium from the environment using a simple epoxy seal, glass-to-metal seal, or other suitable seal.

The protected anode was then inserted into the cylindrical air electrode to fabricate a cylindrical battery, as shown in Figure 3A. Alternatively, the anode array can be inserted into a prismatic air electrode, as shown in Figure 3B.

Li/water, Li/metal hydride or Li/metal oxide cells can also be constructed using this technology by replacing the air electrode with a suitable aqueous, metal hydride or metal oxide cathode system as described herein above.

In addition to the use of lithium metal rods or wires (in capillaries), the present invention is also useful for isolating rechargeable _LiCx anodes from aqueous or other corrosive environments. In this case, a suitable anolyte (transfer electrolyte) solvent is used in the tubular anode to form a passive film on the lithiated carbon electrode. This will allow the construction of high-surface-area Li-ion-type batteries using a large number of specialized cathodes such as air, water, metal hydrides, or metal oxides, such as shown in Figure 3.

Example

The following examples provide details illustrating the beneficial properties of Li metal and Li-ion aqueous battery cells according to the present invention. These examples are provided to illustrate and more clearly explain the content of the invention and are in no way intended to be limiting.

Embodiment 1: Li/seawater battery

A series of experiments were carried out in which a commercial ion-conducting glass-ceramic from OHARA Corporation was used as the membrane separating the aqueous catholyte from the non-aqueous anolyte. The battery structure is Li/non-aqueous electrolyte/glass-ceramic/aqueous electrolyte/Pt. A lithium foil with a thickness of 125 μm from Chemetall Foote was used as the anode. The thickness of the glass-ceramic plate is in the range of 0.3-0.48 mm. The glass-ceramic plate was secured within the electrochemical cell using two O-rings such that the glass-ceramic plate was exposed to the aqueous environment from one side and the non-aqueous environment from the other side. In this case, the aqueous electrolyte comprised artificial seawater prepared with 35 ppt "InstantOcean" from Aquarium Systems, Inc. The conductivity of seawater was measured to be 4.5×10 ^-2 S/cm. A microporous Celgard membrane placed on the other side of the glass-ceramic was filled with a non-aqueous electrolyte consisting of 1M _LiPF6 dissolved in propylene carbonate. The filling volume of the non-aqueous electrolyte is 0.25ml/ ^1cm2 of the lithium electrode surface. When the battery circuit is completed, hydrogen reduction is facilitated using a platinum counter electrode fully submerged in seawater catholyte. The potential of the Li anode in the cell was controlled using an Ag/AgCl reference electrode. The measured values were recalculated as potentials on the Standard Hydrogen Electrode (SHE) scale. The open circuit potential (OCP) that most closely corresponds to the thermodynamic potential difference between Li/Li ⁺ and H ₂ /H ⁺ in water was observed to be 3.05 volts ( FIG. 4 ). When the circuit is closed, hydrogen evolution is immediately observed at the Pt electrode, which is an indication of the anode and cathode electrode reactions in the cell, 2Li = 2Li ⁺ +2e ^- and 2H ⁺ +2e ^- = _H2 . The potential-time curves for Li anodic dissolution at ^a discharge rate of 0.3 mA/cm are provided in Figure 2. The results indicated a working cell with a stable discharge voltage. It should be emphasized that in all experiments using Li anodes in direct contact with seawater, Li utilization was very poor, at ^low This type of battery cannot be used at all at moderate current densities.

Example 2: Li/air battery

The cell structure was similar to that in the previous examples, but with the Pt electrode fully submerged in the electrolyte, this test cell had an air electrode fabricated for a commercial Zn/air cell. The aqueous electrolyte used was 1M LiOH. Li anode and non-aqueous electrolyte were the same as described in previous examples.

The open circuit potential of the cell was observed to be 3.2V. Figure 5 shows the discharge voltage-time curves when the discharge rate is 0.3 mA/cm ² . The cells exhibited a discharge voltage of 2.8-2.9V over 14 hours. This result indicates that good performance can be obtained for Li/air cells with a solid electrolyte membrane separating the aqueous catholyte and non-aqueous anolyte.

Example 3: Li-ion battery

In these experiments, a commercial ion-conducting glass-ceramic from OHARA Corporation was used as the membrane separating the aqueous catholyte from the non-aqueous anolyte. The battery structure is carbon/nonaqueous electrolyte/glass-ceramic plate/aqueous electrolyte/Pt. A commercial carbon electrode comprising synthetic graphite on a copper substrate similar to that commonly used in lithium-ion batteries was used as the anode. The thickness of the glass-ceramic plate is 0.3 mm. The glass-ceramic plate was secured within the electrochemical cell using two O-rings such that the glass-ceramic plate was exposed to the aqueous environment from one side and the non-aqueous environment from the other side. Aqueous electrolytes include 2M LiCl and 1M HCl. A two-layer microporous Celgard separator placed on the other side of the glass-ceramic was filled with a non-aqueous electrolyte consisting of 1M _LiPF6 dissolved in a mixture of ethylene carbonate and dimethyl carbonate (1:1 by volume). . A lithium wire reference electrode was placed between the two Celgard separators to control the potential of the carbon anode during cycling. A platinum mesh completely submerged in a 2M LiCl, 1M HCl solution was used as the battery cathode. The potential of the carbon electrode and the voltage drop across the glass-ceramic plate, and the potential of the Pt cathode during cycling were controlled using an Ag/AgCl reference electrode placed in the aqueous electrolyte. The open circuit voltage (OCV) of the cell was observed to be approximately 1 volt. A voltage difference of 3.2 volts was observed between the Li reference electrode and the Ag/AgCl reference electrode, which closely corresponded to the thermodynamic values. The cell was charged at 0.1 mA/ ^cm2 until the carbon electrode potential reached 5 mV against the Li reference electrode, and then charged at 0.05 mA/ ^cm2 using the same cut-off potential. The discharge rate is 0.1mA/cm ² , and the discharge cut-off potential of the carbon anode to the Li reference electrode is 1.8V. The data in Figure 6 demonstrate that cells with carbon-intercalated anodes and aqueous electrolytes containing Li cations can work reversibly. This is the first known example of using an aqueous solution instead of a solid lithiated oxide cathode as a Li ion source for carbon anode charging in a Li-ion battery.

Example 4: Performance of glass-ceramic protected thick Li anodes in aqueous electrolytes

Design tests were performed for experimental Li/water cells of various Li foil thicknesses in aqueous electrolytes. The cell shown in Figure 8 contained an anode compartment with a protected Li foil anode with an active area of ^2.0 cm on a Cu substrate. Li electrodes with a thickness of about 3.3-3.5 mm were fabricated from Li metal rods. The fabrication process includes extrusion and rolling of Li rods, followed by static extrusion of the resulting foil onto the surface of the Ni-mesh current collector using a hydraulic press. A die with a polypropylene body was used for the extrusion operation to avoid chemical reactions with the Li foil. A glass-ceramic membrane with a thickness of approximately 50 micrometers is secured within the electrochemical cell using two O-rings such that the glass-ceramic membrane is exposed from one side to the aqueous environment (catholyte) and from the other side to the non-aqueous Environment (anolyte). The anolyte provides a liquid intermediate layer between the anode and the surface of the glass-ceramic membrane.

The cells were filled with an aqueous catholyte of 4M _NH4Cl , which allowed the cathode to be buffered during cell storage and discharge. A microporous Celgard separator placed on the other side of the glass-ceramic membrane was filled with a non-aqueous anolyte consisting of 1 M _LiClO dissolved in propylene carbonate. The anode compartment is sealed against the aqueous solution so that only the protective glass-ceramic membrane is exposed to the aqueous environment, the reference electrode and the wire mesh counter electrode. The cell body made of borosilicate glass was filled with 100 ml of catholyte. A Ti mesh counter electrode was used as the cathode to promote hydrogen evolution (water reduction) during Li anode dissolution. The potential of the Li anode during discharge was controlled using an Ag/AgCl reference electrode placed close to the surface of the protective glass film. The measured values were recalculated as potentials on the Standard Hydrogen Electrode (SHE) scale. The cell is equipped with a vent to release the hydrogen gas generated at the cathode.

The potential-time curves of the continuous discharge of the battery are shown in FIG. 7 . The battery exhibited a very long discharge of almost 1400 hours at a closed circuit voltage of about 2.7-2.9V. The discharge capacity value obtained is very large, about 650 mAh/cm ² . Over 3.35 mm of Li was removed along the Li anode/aqueous electrolyte interface without damaging the 50 μm thick protective glass-ceramic membrane. The thickness of the Li foil used in this experiment was in the range of 3.35–3.40 mm. Post hoc analysis of the discharged Li anode confirmed that the full amount of Li was stripped from the Ni current collector at the end of cell discharge. This demonstrates that the Coulombic efficiency of the protected Li anode discharge is close to 100%.

The performance of Li/air prismatic cells was speculated using the obtained Li discharge capacity. In Fig. 9, the specific energy predictions for cells with varying protective Li thicknesses and the values for the gravimetric specific energy of cells with a glass protective anode with a Li thickness of 3.3 mm are shown. The figure also illustrates the cell configuration and shows the parameters used for the calculations. The cell size corresponds to the area of a business card (approximately 45 cm ² ) and a thickness of approximately 6 mm (including a 3.3 mm Li anode). This yields a very large supposed capacity of 90Wh. As can be seen from Figure 9, the experimentally obtained discharge capacity of the glass-protected anode allows the construction of Li/air cells with exceptionally high performance characteristics.

Another Embodiment - Li/Water Batteries and Hydrogen Generators for Fuel Cells

The use of a protective construction on an active metal electrode according to the invention allows the construction of the above-mentioned active metal/water battery with negligible corrosion current. Li/water batteries have a very high theoretical energy density of 8450 Wh/kg. The battery reaction is Li+H ₂ O=LiOH+1/2H ₂ . Although the hydrogen produced by the cell reaction is generally no longer used, it is used in this embodiment of the invention to fuel an ambient temperature fuel cell. The hydrogen produced can be delivered directly to the fuel cell or can be used to recharge the metal hydride alloy for later use in the fuel cell. At least one company, Millenium Cell " http://www.millenniumcell.com/news/tech.html " utilizes the reaction of sodium borohydride with water to produce hydrogen. However, this reaction requires the use of a catalyst, and the energy generated by the chemical reaction of _NaBH4 and water is lost as heat.

NaBH ₄ +2H ₂ O→4H ₂ +NaBO ₂

When combined with the fuel cell reaction H ₂ +O ₂ =H ₂ O, the fuel cell reaction is considered to be:

NaBH ₄ +2O ₂ →2H ₂ O+NaBO ₂

The energy density of this system can be calculated from the equivalents of _NaBH4 reactant (38/4 = 9.5 grams/equivalent). The gravimetric capacity of NaBH ₄ is 2820 mAh/g; since the cell voltage is about 1, the specific energy of this system is 2820 Wh/kg. If the energy density is calculated based on the final product _NaBO2 , the energy density is lower, about 1620Wh/kg.

In the case of a Li/water battery, hydrogen production proceeds by the electrochemical reaction believed to be described below:

Li+H ₂ O=LiOH+1/2H ₂

In this case, the energy of the chemical reaction is converted into electricity in the 3-volt battery, and then the hydrogen is converted into water in the fuel cell, the overall reaction is considered to be as follows:

Li+1/2H ₂ O+1/4O ₂ ＝LiOH

All of the chemical energy is theoretically converted into electrical energy. At a cell potential of about 3 V, the energy density based on a lithium anode is 3830 mAh/g and 11500 Wh/kg (4 times higher than _NaBH4 ). If the weight of water required for the reaction is included, the energy density is 5030Wh/kg. If the energy density is based on the weight of the discharge product LiOH, it is 3500 Wh/kg, or twice the energy density of the _NaBO2 system. This is comparable to previous concepts, which also considered the reaction of lithium metal with water to produce hydrogen. In that case, the energy density is reduced by a factor of 3 because most of the energy in the Li/ _H2O reaction is lost as heat, and the energy density is based on the cell potential of the _H2 / _O2 pair which is actually less than 1 (compared to Li/H ₂ O's 3 opposite). In this embodiment of the invention shown in Figure 10, the generation of hydrogen is also carefully controlled by the load on the Li/water cell, which has a long shelf life due to the protective film, and the hydrogen leaving the cell Has been humidified for _H2 /air fuel cells.

in conclusion

While the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the invention. In particular, although the invention has been described primarily with reference to lithium metal, alloys or intercalation anodes, the anode may consist of any active metal, especially other alkali metals such as sodium. It should be noted that there are many alternative ways of implementing the methods and compositions of the invention. Accordingly, the embodiments of the present invention are to be considered as illustrative rather than restrictive, and the invention is not limited to the details given herein.

All documents cited herein are incorporated by reference for all purposes.

Claims (82)

1. An electrochemical cell structure, comprising: an anode comprising a material selected from the group consisting of active metals, active metal ions, active metal alloying metals, and active metal intercalation materials; and An ionically conductive protective construction on the first surface of the anode, the construction comprising: an active metal ion conducting membrane layer comprising a semipermeable membrane impregnated with a liquid or gel phase non-aqueous anolyte, the membrane layer being chemically compatible with the active metal and contacting the anode, and A substantially water impermeable ionically conductive layer chemically compatible with the membrane layer and the aqueous environment and in contact with the membrane layer, wherein said substantially water impermeable ionically conductive layer comprises an active metal ion conductor selected from a glassy or amorphous state, a ceramic active metal ion conductor, and Materials in glass-ceramic active metal ion conductors. 2. The structure of claim 1, wherein the semipermeable membrane is a microporous polymer. 3. The structure of claim 2, wherein the anolyte is in the liquid phase. 4. The structure of claim 3, wherein the anolyte comprises a solvent selected from the group consisting of organic carbonates, ethers, esters, formates, lactones, sulfones, sulfolanes, and combinations thereof. 5. The structure of claim 4, wherein the anolyte comprises a solvent and a supporting salt, wherein the solvent is selected from the group consisting of EC, PC, DEC, DMC, EMC, THF, 2MeTHF, 1,2-DME or higher glyme, sulfolane , methyl formate, methyl acetate and their combinations, the supporting salt is selected from LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiSO ₃ CF ₃ , LiN(CF ₃ SO ₂ ) ₂ and LiN(SO ₂ C ₂ F ₅ ) ₂ . 6. The structure of claim 5, wherein the anolyte further comprises 1,3-dioxolane. 7. The structure of claim 2, wherein the anolyte is in a gel phase. 8. The structure of claim 7, wherein the anolyte comprises a gelling agent selected from the group consisting of PVdF, PVdF-HFP copolymers, PAN and PEO and mixtures thereof, a plasticizer and a Li salt; the plasticizer being selected from the group consisting of EC, PC, DEC, DMC, EMC, THF, 2MeTHF, 1,2-DME and their mixtures; Li salt selected from LiPF ₆ , LiBF _{4 , LiAsF 6 , LiClO 4 , LiSO 3 CF 3 , LiN (} CF ₃ SO ₂ ) ₂ and LiN(SO ₂ C ₂ F ₅ ) ₂ . 9. The structure of claim 1, wherein said active metal is an alkali metal. 10. The structure of claim 1, wherein the active metal is lithium or a lithium alloy. 11. The structure of claim 10, wherein the substantially water-impermeable ionically conductive layer has the following composition and comprises Li _1+x (M, Al, Ga) _x (Ge _1-y Ti _y ) _2-x (PO ₄ ) ₃ and/or Li _1+x+y Q _x Ti _2-x Si _y P _3-y O ₁₂ composed of ion-conducting glass-ceramics in the main crystal phase: composition: _{P2O5 26-55mol} % SiO ₂ 0-15mol% GeO ₂ +TiO ₂ 25-50mol% Of which GeO ₂ 0-50mol% TiO ₂ 0-50mol% ZrO ₂ 0-10mol% M ₂ O ₃ 0<10mol% Al ₂ O ₃ 0-15mol% _{Ga2O3 0-15mol} % _Li2O 3-25mol% Where X≤0.8 and 0≤Y≤1.0 in Li _1+x (M, Al, Ga) _x (Ge _1-y Ti _y ) _2-x (PO ₄ ) ₃ , M is selected from Nd, Sm, Eu, Elements of Gd, Tb, Dy, Ho, Er, Tm and Yb, Li _1+x+y Q _x Ti _2-x Si _y P _3-y O ₁₂ in 0<X≤0.4 and 0<Y≤0.6, Q It is Al or Ga. 12. The structure of claim 1, wherein the substantially water-impermeable ionically conductive layer has an ionic conductivity of at least ^10-5 S/cm. 13. The structure of claim 1, wherein the non-aqueous electrolyte separator layer has an ionic conductivity of at least ^10-5 S/cm. 14. The structure of claim 1, wherein the anode comprises an active metal. 15. The structure of claim 1, wherein the anode includes active metal ions. 16. The structure of claim 1, wherein the anode comprises an active metal alloying metal. 17. The structure of claim 16, wherein the active metal alloying metal is selected from the group consisting of Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, In and Sb. 18. The structure of claim 1, wherein the anode comprises an active metal intercalation material. 19. The structure of claim 18, wherein the active metal intercalation material comprises carbon. 20. A battery cell comprising: An electrochemical cell structure according to any preceding claim; and cathode structure. 21. The battery of claim 20, wherein the cathode structure comprises an electronically conductive component, an ionically conductive component, and an electrochemically active component, wherein at least one of the cathode structure components comprises an aqueous component. 22. The battery of claim 21, wherein the cathode structure comprises an electrochemically active component comprising water. 23. The cell of claim 22, wherein the aqueous electrochemically active component is water. 24. The cell of claim 23, wherein the aqueous electrochemically active component comprises a water-soluble oxidizing agent selected from the group consisting of gaseous, liquid, and solid oxidizing agents, and combinations thereof. 25. The battery of claim 24, wherein the water-soluble gaseous oxidant is selected from _O2 , _SO2 , and _NO2 , and the water-soluble solid _oxidizer is selected from _NaNO2 , _KNO2 , _{Na2SO3 ,} and _K2SO3 . 26. The battery of claim 24, wherein the water-soluble oxidizing agent is a peroxide. 27. The battery of claim 26, wherein the water-soluble oxidizing agent is hydrogen peroxide. 28. The battery of claim 21, wherein the ionically conductive member and the electrochemically active member are comprised of a water-based electrolyte. 29. The battery of claim 28, wherein the water-based electrolyte is selected from the group consisting of strong acid solutions, weak acid solutions, alkaline solutions, neutral solutions, amphoteric solutions, peroxide solutions, and combinations thereof. 30. The battery of claim ₂₈ , wherein the water-based electrolyte comprises a compound selected from the group consisting of HCl, _{H2SO4 , H3PO4} , acetic acid/lithium acetate, LiOH, seawater, LiCl, LiBr, LiI, _NH4Cl , _NH4Br , and Aqueous solutions of hydrogen peroxide and members of combinations thereof. 31. The battery of claim 30, wherein the water-based electrolyte is seawater. 32. The battery of claim 30, wherein the water-based electrolyte comprises seawater and hydrogen peroxide. 33. The battery of claim 30, wherein the water-based electrolyte comprises an acidic peroxide solution. 34. The battery of claim 30, wherein the hydrogen peroxide is dissolved in the water-based electrolyte flowing through the battery. 35. The battery of claim 21, wherein the electronically conductive member of the cathode structure is a porous catalytic support. 36. The battery of claim 35, wherein the porous catalytic electronically conductive support comprises nickel. 37. The battery of claim 35, wherein the porous catalytic electronically conductive support is treated with an ionomer. 38. The battery of claim 22, wherein the cathode structure electrochemically active material comprises air. 39. The battery of claim 38, wherein the air includes moisture. 40. The battery of claim 39, wherein the ionically conductive material comprises an aqueous composition. 41. The battery of claim 40, wherein the ionically conductive material further comprises an ionomer. 42. The battery of claim 41, wherein the ionically conductive material comprises a neutral or acidic water-based electrolyte. 43. The battery of claim 42, wherein the water-based electrolyte comprises LiCl. 44. The battery of claim 42, wherein the water-based electrolyte comprises one of _NH4Cl and HCl. 45. The battery of claim 21, wherein the cathode structure comprises an air diffusion membrane, a hydrophobic polymer layer, an oxygen reduction catalyst, an electrolyte, and an electronically conductive member/current collector. 46. The battery of claim 45, wherein the electronically conductive member/current collector comprises a porous nickel material. 47. The battery of claim 45, further comprising a separator disposed between the protective membrane and the cathode structure. 48. The cell of claim 21, wherein the electrochemically active component of the cathode structure comprises a metal hydride alloy. 49. The battery of claim 48, wherein the ionically conductive member of the cathode structure comprises a water-based electrolyte. 50. The battery of claim 49, wherein the water-based electrolyte is acidic. 51. The battery of claim 50, wherein the water-based electrolyte comprises a halide acid or an acid salt. 52. The battery of claim 51, wherein the water-based electrolyte comprises a chloride or bromide acid or acid salt. 53. The battery of claim 52, wherein the water-based electrolyte comprises one of HCl, HBr, _NH4Cl , and _NH4Br . 54. The battery of claim 53, wherein the metal hydride alloy comprises one of AB ₅ and AB ₂ alloys. 55. The battery of claim 20, wherein the battery is a primary battery. 56. The battery of claim 20, wherein the battery is a rechargeable battery. 57. The battery of claim 20, wherein the battery has a flat plate configuration. 58. The battery of claim 20, wherein the battery has a tubular configuration. 59. The battery of claim 21, wherein the active metal is lithium and the cathode structure includes an aqueous ionically conductive component and a transition metal oxide electrochemically active component. 60. The battery of claim 59, wherein the transition metal oxide is selected from the group consisting of NiOOH, AgO, iron oxide, lead oxide, and manganese oxide. 61. The cell of claim 20, wherein the anolyte further comprises a water-insoluble or sparingly water-soluble polymer monomer, and the catholyte of the cathode structure comprises a polymerization initiator for the monomer. 62. The battery of claim 61, wherein the monomer is 1,3-dioxolane. 63. The battery of claim 62, wherein the polymerization initiator comprises at least one of a protic acid and a water-soluble Lewis acid dissolved in the catholyte. 64. The battery of claim 63, wherein the polymerization initiator comprises a benzobenzoyl cation. 65. The battery of claim 20, wherein the cathode structure includes an ionically conductive member. 66. The battery of claim 65, wherein the ionically conductive member comprises a non-aqueous catholyte. 67. The battery of claim 66, wherein the catholyte comprises a material selected from the group consisting of organic liquids and ionic liquids. 68. The cell of claim 67, wherein the catholyte is a solution of a Li salt in an aprotic solvent selected from the group consisting of organic carbonates, ethers, lactones, sulfones, esters, formates, and combinations thereof. 69. The battery of claim 68, wherein the catholyte is selected from the group consisting of EC, PC, DEC, DMC, EMC, THF, 2MeTHF, 1,2-DME and higher glyme, 1,3-dioxolane, Sulfolane, methyl formate, methyl acetate and their combinations, the supporting salt is selected from LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiSO ₃ CF ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ and their combinations. 70. The battery of claim 69, further comprising a dissolved solid, liquid or gaseous oxidant selected from the group consisting of lithium polysulfide, _NO2 , _SO2 , _SOCl2 . 71. The cell of claim 66, wherein the catholyte comprises an ionic liquid selected from the group consisting of imidazolium derivatives, pyridinium derivatives, phosphonium compounds, and tetraalkylammonium compounds, and combinations thereof. 72. The battery of claim 71, wherein the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium tosylate (EMIM-Ts), 1-butyl-3-methylimidazolium octyl sulfate ( BMIM-OctSO4), 1-ethyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium tetrafluoroborate. 73. The battery of claim 20, wherein the battery has a discharge capacity greater than 10 mAh/ ^cm2 . 74. The battery of claim 73, wherein the battery has a discharge capacity greater than 100 mAh/ ^cm2 . 75. The battery of claim 74, wherein the battery has a discharge capacity greater than 500 mAh/ ^cm2 . 76. The battery of claim 30, wherein the anode is 3.35 mm thick Li, the battery is filled with a water-based electrolyte comprising _NH4Cl , and the battery has a discharge capacity of 650 mAh/ ^cm2 . 77. The battery of claim 38, wherein the battery has a 3.3 mm thick Li anode and an area of 45 ^cm2 , with an unencapsulated specific energy of 3400 Wh/l. 78. The battery of claim 77, wherein the battery has a packaged load of 70% and a packaged specific energy of 1000 Wh/l. 79. The cell of claim 23, further comprising a _PEMH2 / _O2 fuel cell that captures hydrogen released from the cathode structure during redox reactions of the battery cell. 80. A method of manufacturing a battery cell according to claim 20, comprising: The following parts are provided: active metal anode; cathode structure; and An ionically conductive protective construction on the first surface of the anode, the construction comprising: an active metal ion conducting membrane layer comprising a non-aqueous anolyte, the membrane layer being chemically compatible with the active metal and contacting the anode, and a substantially water-impermeable ionically conductive layer that is chemically compatible with, and in contact with, the separator layer and the cathode structure; and Assemble the above parts. 81. The method of claim 80, wherein the substantially water impermeable ionically conductive layer is tubular. 82. A method for stopping an electrochemical cell according to claim 20 in the event of structural damage, comprising providing in the anolyte a water-insoluble or slightly water-soluble polymer monomer, in the catholyte Provides a polymerization initiator for the monomer.

Images