Composite interlayer with high lithium salt concentration for lithium metal negative electrode of lithium ion circulating battery and manufacturing method thereof

Abstract

The present invention relates to a composite interlayer having a high lithium salt concentration for a lithium metal negative electrode of a lithium ion circulating battery and a method for manufacturing the same. A battery circulating lithium ions includes a lithium metal negative electrode, a positive electrode, a porous separator disposed between opposing facing surfaces of the lithium metal negative electrode and the positive electrode, and a composite interlayer disposed on the facing surfaces of the lithium metal negative electrode and between the lithium metal negative electrode and the porous separator. The composite intermediate layer includes a polymer matrix phase and a lithium salt dispersed phase embedded in the polymer matrix phase and dispersed throughout the polymer matrix phase. The lithium salt dispersed phase comprises greater than or equal to about 10% and less than or equal to about 50% by weight of the composite intermediate layer.

Description

Technical Field

[0001] The present disclosure relates to cycling lithium ion batteries, and more particularly to composite interlayers for lithium metal negative electrodes for cycling lithium ion batteries. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the present disclosure. To the extent that work currently named as inventors is described in this section, and aspects of the specification that may not have been otherwise identified as prior art at the time of filing, are not admitted, either explicitly or implicitly, as prior art to the present disclosure.

[0003] A battery pack that circulates lithium ions typically includes a positive electrode, a negative electrode separated from the positive electrode, and an ion-conductive electrolyte that provides a lithium ion conducting medium between the positive electrode and the negative electrode during discharge and charge of the battery pack. A polymer separator is typically disposed between the positive electrode and the negative electrode, which physically separates and electrically isolates the negative electrode and the positive electrode from each other while allowing lithium ions to pass through. The positive electrode and the negative electrode are typically disposed as thin layers on the surfaces of the respective positive electrode collector and the negative electrode collector.

[0004] Due to its high gravimetric and volumetric capacities (3860 mAh / g and 2061 mAh / cm 3 ) and its relatively low reduction potential (-3.04V vs standard hydrogen electrode), lithium metal is an ideal negative electrode material for batteries that cycle lithium ions. When lithium metal is used as a negative electrode material in a battery that cycles lithium ions, the lithium metal deposited on the surface of the negative electrode current collector may exhibit a moss-like or dendritic structure, which may reduce the cycle efficiency of the battery. In addition, due to the low reduction potential of lithium metal, undesirable side reactions may occur at the interface between the lithium metal negative electrode and the electrolyte, which may lead to the decomposition of the electrolyte and the consumption of active lithium. The large volume changes experienced by the lithium metal negative electrode during repeated cycles may exacerbate the above situation. Summary of the invention

[0005] A battery pack for circulating lithium ions includes a lithium metal negative electrode, a positive electrode, a porous separator and a composite intermediate layer according to one or more embodiments of the present disclosure. The positive electrode includes an electroactive positive electrode material and is separated from the lithium metal negative electrode. The lithium metal negative electrode and the positive electrode have opposite facing surfaces. The porous separator is disposed between the opposite facing surfaces of the lithium metal negative electrode and the positive electrode. The porous separator has a first side facing the lithium metal negative electrode and an opposite second side facing the positive electrode. The composite intermediate layer is disposed on the facing surface of the lithium metal negative electrode and between the lithium metal negative electrode and the porous separator. The composite intermediate layer comprises a polymer matrix phase and a lithium salt dispersed phase embedded in the polymer matrix phase and dispersed throughout the polymer matrix phase. The lithium salt dispersed phase accounts for greater than or equal to about 10% and less than or equal to about 50% by weight of the composite intermediate layer.

[0006] The polymer matrix phase may comprise at least one polymer selected from the group consisting of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), poly(acrylic acid) (PAA), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), poly(vinyl alcohol) (PVA) and polyvinyl pyrrolidone (PVP).

[0007] The lithium salt dispersed phase may include at least one lithium salt selected from lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTf), lithium bis(perfluoroethane)sulfonyl imide (LiBETI), lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide (LiDMSI) and cyclohexafluoropropane-1,1-bis(sulfonyl)imide (LiHPSI).

[0008] The battery pack may further include an electrolyte that wets the facing surface of the lithium metal negative electrode and penetrates the porous separator and the composite interlayer. The electrolyte may include an organic solvent and a lithium salt, wherein the concentration of the lithium salt in the electrolyte is less than the concentration of the lithium salt in the composite interlayer.

[0009] The electrolyte may have a lithium salt concentration of about 1 mol / L, and the composite interlayer may have a lithium salt concentration of greater than or equal to about 2 mol / dm 3 .

[0010] The lithium salt dispersed phase may be fixed in the polymer matrix phase of the composite interlayer so that the lithium salt dispersed phase is not released from the composite interlayer when the composite interlayer is infiltrated by the electrolyte.

[0011] The composite interlayer can extend from the facing surface of the lithium metal negative electrode to the first side of the porous separator. In such a case, the composite interlayer can have a thickness greater than or equal to about 5 microns and less than or equal to about 50 microns.

[0012] The porous separator can include a polyolefin and can have a thickness greater than or equal to about 5 microns and less than or equal to about 500 microns.

[0013] A battery pack for cycling lithium ions includes a lithium metal negative electrode, a positive electrode, a porous separator, a composite intermediate layer and an electrolyte according to one or more embodiments of the present disclosure. The positive electrode is separated from the lithium metal negative electrode and includes an electroactive positive electrode material. The lithium metal negative electrode and the positive electrode have opposite facing surfaces. The porous separator is disposed between the opposite facing surfaces of the lithium metal negative electrode and the positive electrode. The porous separator has a first side facing the lithium metal negative electrode and an opposite second side facing the positive electrode. The composite intermediate layer is disposed on the facing surface of the lithium metal negative electrode and between the lithium metal negative electrode and the porous separator. The composite intermediate layer comprises a polymer matrix phase and a lithium salt dispersed phase embedded in the polymer matrix phase and dispersed throughout the polymer matrix phase. The lithium salt dispersed phase accounts for greater than or equal to about 10% and less than or equal to about 50% by weight of the composite intermediate layer. The electrolyte wets the facing surface of the lithium metal negative electrode and penetrates the porous separator and the composite intermediate layer. The electrolyte comprises an organic solvent and a lithium salt. The lithium salt concentration in the electrolyte is less than the lithium salt concentration in the composite interlayer.

[0014] The polymer matrix phase may comprise poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP).

[0015] The lithium salt dispersed phase may include lithium bis(fluorosulfonyl)imide (LiFSI).

[0016] The electrolyte may have a lithium salt concentration of about 1 mol / L. The composite interlayer may have a lithium salt concentration of greater than or equal to about 2 mol / dm3.

[0017] The lithium salt dispersed phase may be fixed in the polymer matrix phase of the composite interlayer so that the lithium salt dispersed phase is not released from the composite interlayer when the composite interlayer is infiltrated by the electrolyte.

[0018] The composite interlayer can extend from the facing surface of the lithium metal negative electrode to the first side of the porous separator and can have a thickness greater than or equal to about 5 microns and less than or equal to about 50 microns.

[0019] A method for manufacturing a battery pack for cycling lithium ions is disclosed. In the method, a precursor comprising an organic solvent, a polymer in the organic solvent, and a lithium salt is prepared. The precursor is deposited on a substrate to form a precursor layer thereon. The organic solvent is then removed from the precursor layer to form a composite intermediate layer comprising a polymer and a lithium salt embedded in and dispersed throughout the polymer.

[0020] The lithium salt may comprise greater than or equal to about 3% and less than or equal to about 15% by weight of the precursor.The polymer may comprise greater than or equal to about 15% and less than or equal to about 70% by weight of the precursor.

[0021] The organic solvent may have a boiling point greater than or equal to about 80°C and less than about 180°C.

[0022] The organic solvent may include acetonitrile (ACN), N-methyl-2-pyrrolidone (NMP), methoxymethane (DME), dimethyl carbonate (DMC), dimethylformamide (DMF), or a combination thereof.

[0023] The substrate may be a lithium metal layer disposed on a metal current collector. In such a case, the method may further include assembling the composite intermediate layer into a battery pack.

[0024] The substrate may be made of plastic or glass. In such a case, the method may further include peeling the composite intermediate layer from the substrate, placing the composite intermediate layer on the surface of the lithium metal layer, and assembling the composite intermediate layer and the lithium metal layer into a battery pack.

[0025] The present invention discloses the following scheme:

[0026] Solution 1. A circulating lithium ion battery pack, the battery pack comprising:

[0027] Lithium metal negative electrode;

[0028] a positive electrode spaced apart from a negative lithium metal electrode, the positive electrode comprising an electroactive positive electrode material, the negative lithium metal electrode and the positive electrode having opposing facing surfaces;

[0029] a porous separator disposed between opposing facing surfaces of the lithium metal negative electrode and the positive electrode, the porous separator having a first side facing the lithium metal negative electrode and an opposite second side facing the positive electrode; and

[0030] A composite intermediate layer disposed on a facing surface of a lithium metal negative electrode and between the lithium metal negative electrode and a porous separator, the composite intermediate layer comprising:

[0031] a polymer matrix phase, and

[0032] A lithium salt dispersed phase is embedded in and dispersed throughout the polymer matrix phase, the lithium salt dispersed phase accounting for greater than or equal to about 10% and less than or equal to about 50% by weight of the composite interlayer.

[0033] Option 2. A battery pack according to Option 1, wherein the polymer matrix phase comprises at least one polymer selected from poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), poly(acrylic acid) (PAA), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), poly(vinyl alcohol) (PVA) and polyvinyl pyrrolidone (PVP).

[0034] Option 3. A battery according to Option 1, wherein the lithium salt dispersed phase comprises at least one lithium salt selected from lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTf), lithium bis(perfluoroethane)sulfonyl imide (LiBETI), lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide (LiDMSI) and cyclohexafluoropropane-1,1-bis(sulfonyl)imide (LiHPSI).

[0035] Solution 4. The battery pack according to Solution 1, further comprising:

[0036] An electrolyte wets the facing surface of the lithium metal negative electrode and penetrates the porous separator and the composite interlayer, the electrolyte comprising an organic solvent and a lithium salt, wherein the concentration of the lithium salt in the electrolyte is less than the concentration of the lithium salt in the composite interlayer.

[0037] Option 5. A battery pack according to Option 4, wherein the electrolyte has a lithium salt concentration of about 1 mol / L, and wherein the composite interlayer has a lithium salt concentration greater than or equal to about 2 mol / dm3.

[0038] Option 6. A battery according to Option 4, wherein the lithium salt dispersed phase is fixed in the polymer matrix phase of the composite interlayer so that the lithium salt dispersed phase is not released from the composite interlayer when the composite interlayer is penetrated by the electrolyte.

[0039] Option 7. A battery pack according to Option 1, wherein the composite intermediate layer extends from the facing surface of the lithium metal negative electrode to the first side of the porous separator, and wherein the composite intermediate layer has a thickness greater than or equal to about 5 microns and less than or equal to about 50 microns.

[0040] Option 8. The battery pack of Option 7, wherein the porous separator comprises a polyolefin and has a thickness greater than or equal to about 5 microns and less than or equal to about 500 microns.

[0041] Solution 9. A circulating lithium ion battery pack, the battery pack comprising:

[0042] Lithium metal negative electrode;

[0043] a positive electrode spaced apart from a negative lithium metal electrode, the positive electrode comprising an electroactive positive electrode material, the negative lithium metal electrode and the positive electrode having opposing facing surfaces;

[0044] a porous separator disposed between opposing facing surfaces of the lithium metal negative electrode and the positive electrode, the porous separator having a first side facing the lithium metal negative electrode and an opposite second side facing the positive electrode;

[0045] a composite interlayer disposed on a facing surface of a lithium metal negative electrode and between the lithium metal negative electrode and a porous separator, the composite interlayer comprising a polymer matrix phase and a lithium salt dispersed phase embedded in and dispersed throughout the polymer matrix phase, the lithium salt dispersed phase accounting for greater than or equal to about 10% and less than or equal to about 50% by weight of the composite interlayer; and

[0046] an electrolyte that wets the facing surface of the lithium metal negative electrode and penetrates the porous separator and the composite interlayer, the electrolyte comprising an organic solvent and a lithium salt,

[0047] The lithium salt concentration in the electrolyte is less than the lithium salt concentration in the composite intermediate layer.

[0048] Embodiment 10. The battery pack according to Embodiment 9, wherein the polymer matrix phase comprises poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP).

[0049] Embodiment 11. A battery according to Embodiment 9, wherein the lithium salt dispersed phase comprises lithium bis(fluorosulfonyl)imide (LiFSI).

[0050] Embodiment 12. A battery pack according to Embodiment 9, wherein the electrolyte has a lithium salt concentration of about 1 mol / L, and wherein the composite interlayer has a lithium salt concentration greater than or equal to about 2 mol / dm3.

[0051] Option 13. A battery pack according to Option 9, wherein the lithium salt dispersed phase is fixed in the polymer matrix phase of the composite interlayer so that the lithium salt dispersed phase is not released from the composite interlayer when the composite interlayer is penetrated by the electrolyte.

[0052] Option 14. A battery pack according to Option 9, wherein the composite intermediate layer extends from the facing surface of the lithium metal negative electrode to the first side of the porous separator, and wherein the composite intermediate layer has a thickness greater than or equal to about 5 microns and less than or equal to about 50 microns.

[0053] Solution 15. A method for manufacturing a cycling lithium-ion battery, the method comprising:

[0054] preparing a precursor comprising an organic solvent, a polymer in the organic solvent, and a lithium salt;

[0055] depositing the precursor on a substrate to form a precursor layer thereon; and

[0056] The organic solvent is removed from the precursor layer to form a composite interlayer comprising a polymer and a lithium salt embedded in and dispersed throughout the polymer.

[0057] Option 16. A method according to Option 15, wherein the lithium salt accounts for greater than or equal to about 3% and less than or equal to about 15% by weight of the precursor, and wherein the polymer accounts for greater than or equal to about 15% and less than or equal to about 70% by weight of the precursor.

[0058] Embodiment 17. The method according to Embodiment 15, wherein the organic solvent has a boiling point greater than or equal to about 80°C and less than about 180°C.

[0059] Scheme 18. The method according to Scheme 15, wherein the organic solvent comprises acetonitrile (ACN), N-methyl-2-pyrrolidone (NMP), methoxymethane (DME), dimethyl carbonate (DMC), dimethylformamide (DMF) or a combination thereof.

[0060] Option 19. A method according to Option 15, wherein the substrate is a lithium metal layer disposed on a metal current collector, and wherein the method further comprises assembling the composite intermediate layer into a battery pack.

[0061] Option 20. A method according to Option 15, wherein the substrate is made of plastic or glass, and wherein the method further includes peeling the composite intermediate layer from the substrate, placing the composite intermediate layer on the surface of the lithium metal layer, and assembling the composite intermediate layer and the lithium metal layer into a battery pack.

[0062] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0064] Figure 1 is a schematic perspective view of a motor vehicle powered by a battery pack including a plurality of battery modules.

[0065] Figure 2 yes Figure 1 Schematic cross-sectional view of a portion of one of the battery modules of FIG. 1 , the battery module including a plurality of cycling lithium-ion electrochemical cells or batteries.

[0066] Figure 3 is a schematic cross-sectional view of a battery stack for cycling lithium ions, the battery stack including a negative electrode, a positive electrode, a porous separator, a composite interlayer disposed between the negative electrode and the porous separator, and an electrolyte permeating the positive electrode, the porous separator, and the composite interlayer.

[0067] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0068] The composite intermediate layer of the present disclosure can be disposed on the facing surface of the lithium metal negative electrode of a battery pack that cycles lithium ions to improve its cycling stability. The composite intermediate layer is electrically insulating and ionically conductive and is configured to establish a locally high lithium salt concentration along the facing surface of the lithium metal negative electrode compared to the lithium salt concentration in the electrolyte, which may help prevent undesirable chemical reactions between the lithium metal negative electrode and the electrolyte and may inhibit the undesirable formation of lithium dendrites. The composite intermediate layer can establish a high lithium salt concentration along the facing surface of the lithium metal negative electrode without significantly increasing the total lithium salt concentration in the battery pack, which may otherwise increase the cost of the battery pack, without causing corrosion of the aluminum current collector and without increasing the viscosity of the electrolyte.

[0069] Figure 1 A motor vehicle 2 is depicted that is powered by an electric motor 4 that draws power from a battery pack 6 that includes one or more battery modules 8. The battery modules 8 may be electrically coupled together in a series and / or parallel arrangement to meet the capacity and power requirements required by the electric motor 4. The vehicle 2 may be a pure electric vehicle and may be powered entirely by the electric motor 4, or the vehicle 2 may be a hybrid vehicle and may be powered by the electric motor 4 and an internal combustion engine (not shown).

[0070] like Figure 2 As shown in , each battery module 8 includes one or more electrochemical cells or batteries 10 that circulate lithium ions. In practice, the batteries 10 in the battery module 8 are typically assembled as stacked layers, including a negative electrode layer 12, a negative electrode current collector 13, a positive electrode layer 14, a positive electrode current collector 15, and a separator layer 16. Each battery 10 is defined by a negative electrode layer 12 and a positive electrode layer 14 separated from each other by a separator layer 16. The negative electrode layer 12 is disposed on the negative electrode current collector 13 and is electrically connected to the negative electrode current collector 13, and the positive electrode layer 14 is disposed on the positive electrode current collector 15 and is electrically connected to the positive electrode current collector 15. As shown in FIG. Figure 2 As shown in , for efficiency, these layers can be stacked so that some of the negative electrode collectors and positive electrode collectors 13, 15 are double-sided and include negative electrode layers 12 or positive electrode layers 14 on both sides thereof. In this arrangement, adjacent negative electrode layers 12 and positive electrode layers 14 share a single negative electrode collector 13 or positive electrode collector 15.

[0071] Figure 3 An electrochemical cell or battery 20 of circulating lithium ions is depicted. The battery 20 can generate an electric current during discharge, which can be used to power a load device (e.g., an electric motor 4), and can be recharged by connection to a power source. Figure 1 and 2 1 , in aspect, the battery pack 20 may be used to supply power to the motor 4 of the motor vehicle 2. Additionally or alternatively, the battery pack 20 may be used in other transportation applications (e.g., motorcycles, boats, tractors, buses, motorbikes, mobile homes, campers, tanks, and aircraft), and may be used to power stationary and / or portable electronic devices, components, and devices used in a wide variety of other industries and applications, including industrial, residential and commercial buildings, consumer products, industrial equipment and machinery, agricultural or farm equipment, and heavy machinery (as non-limiting examples).

[0072] The battery pack 20 includes a negative electrode 22, a positive electrode 24 separated from the negative electrode 22, a composite intermediate layer 38, and an electrolyte 28. A separator 26 is disposed between a facing surface 40 of the negative electrode 22 and an opposite facing surface 42 of the positive electrode 24. The separator 26 has a first side 44 facing the negative electrode 22 and an opposite second side 46 facing away from the negative electrode 22 and facing the positive electrode 24. The negative electrode 22 is disposed on a negative electrode current collector 30, and the positive electrode 24 is disposed on a positive electrode current collector 32. In practice, the negative electrode current collector 30 and the positive electrode current collector 32 are electrically coupled to a power source or load 34 (e.g., a motor 12) via an external circuit 36.

[0073] The negative and positive electrodes 22, 24 are configured to establish an electrochemical potential difference between the negative and positive electrodes 22, 24 when the battery 20 is at least partially charged. During the discharge process of the battery 20, the electrochemical potential established between the negative and positive electrodes 22, 24 drives spontaneous reduction and oxidation (redox) reactions within the battery 20 and releases lithium ions and electrons at the negative electrode 22. The released lithium ions travel from the negative electrode 22 through the separator 26 and the electrolyte 28 to the positive electrode 24, while the electrons travel from the negative electrode 22 to the positive electrode 24 via the external circuit 36, which generates an electric current. After the negative electrode 22 has been partially or completely depleted of lithium, the battery 20 can be charged by connecting the negative and positive electrodes 22, 24 to a power source 34, which drives non-spontaneous redox reactions within the battery 20 and releases lithium ions and electrons from the positive electrode 24. The repeated discharge and charge of the battery pack 20 may be referred to herein as a "cycle," with a complete charge event followed by a complete discharge event being considered a complete cycle.

[0074] The negative electrode 22 is electrochemically active and is disposed on the main surface of the negative electrode current collector 30. The negative electrode 22 contains lithium (Li) and may be substantially composed of lithium or composed of lithium. For example, the negative electrode 22 may contain more than 97% lithium by weight, or optionally more than 99% lithium. The negative electrode 22 may be substantially free of elements or compounds that undergo a reversible redox reaction with lithium during operation of the battery pack 20. For example, the lithium metal negative electrode 22 may be substantially free of an intercalation host material (intercalation host material) formulated to undergo reversible insertion or embedding of lithium ions or an alloy material that can be electrochemically alloyed with lithium and form a composite phase. In addition, the negative electrode 22 may be substantially free of conversion materials or alloy materials that can be electrochemically alloyed with lithium and form a composite phase. Some examples of materials that may be intentionally excluded from the negative electrode 22 include carbon-based materials (e.g., graphite, activated carbon, carbon black, and graphene), silicon and silicon-based materials, tin oxide, aluminum, indium, zinc, cadmium, lead, germanium, tin, antimony, titanium oxide, lithium titanium oxide, lithium titanate, lithium oxide, metal oxides (e.g., iron oxide, cobalt oxide, manganese oxide, copper oxide, nickel oxide, chromium oxide, ruthenium oxide, and / or molybdenum oxide), metal phosphides, metal sulfides, and metal nitrides (e.g., phosphides, sulfides, and / or nitrides or iron, manganese, nickel, copper, and / or cobalt). The negative electrode 22 may be substantially free of polymer binders. Some examples of polymer binders that may be intentionally excluded from the negative electrode 22 include polyvinylidene fluoride (PVDF), ethylene propylene diene monomer (EPDM) rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), and polyacrylic acid.

[0075] The positive electrode 24 is configured to store and release lithium ions during the discharge and charge processes of the battery 20. The positive electrode 24 can be in the form of a continuous porous material layer disposed on the major surface of the positive electrode current collector 32. The positive electrode 24 includes an electrochemically active (electroactive) material (electroactive positive electrode material), a polymer binder, and an optional conductive material. In one aspect, the electroactive material of the positive electrode 24 can be a particulate material and the particles of the electroactive material of the positive electrode 24 can be blended with a polymer binder and an optional conductive material.

[0076] The electroactive material of the positive electrode 24 can store and release lithium ions by undergoing a reversible redox reaction with lithium. The electroactive material of the positive electrode 24 may include a material that can undergo lithium insertion and deinsertion, or a material that can undergo a conversion reaction with lithium. In the aspect where the electroactive material of the positive electrode 24 includes an intercalation host material that can undergo reversible insertion or insertion of lithium ions, the electroactive material of the positive electrode 24 may include a material of the formula LiMeO 2 The layered lithium transition metal oxide shown, formula LiMePO 4 The olivine-type lithium transition metal oxide shown in FIG. 3 Me 2 (PO 4 ) 3 The monoclinic lithium transition metal oxide shown, formula LiMe 2 O 4 The spinel lithium transition metal oxide shown in the formula LiMeSO 4 F and / or LiMePO 4 F or a combination thereof, wherein Me is a transition metal (e.g., Co, Ni, Mn, Fe, Al, V, or a combination thereof). In aspects where the electroactive material of the positive electrode 24 comprises a conversion material, the electroactive material of the positive electrode 24 may comprise sulfur, selenium, tellurium, iodine, a halide (e.g., a fluoride or a chloride), a sulfide, a selenide, a telluride, an iodide, a phosphide, a nitride, an oxide, an oxysulfide, an oxyfluoride, a sulfur fluoride, a sulfur-oxyfluoride, or lithium and / or a metal compound thereof (e.g., a compound of iron, manganese, nickel, copper, and / or cobalt). The electroactive material of the positive electrode 24 may account for greater than or equal to about 50%, optionally greater than or equal to about 60%, or optionally greater than or equal to about 70% and less than or equal to about 95%, optionally less than or equal to about 90%, or optionally less than or equal to about 80% by weight of the positive electrode 24.

[0077] The polymer binder is electrochemically inactive and may be included in the positive electrode 24 to provide structural integrity to the positive electrode 24 and / or to help the positive electrode 24 adhere to the main surface of the positive electrode current collector 32. Examples of polymer binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM) rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), nitrile rubber (NBR), styrene-butadiene rubber (SBR), styrene ethylene butylene styrene copolymer (SEBS), polyacrylates, alginates, polyacrylic acid, and combinations thereof. The polymer binder may account for greater than or equal to about 1%, or optionally greater than or equal to about 5% and less than or equal to about 10% by weight of the positive electrode 24.

[0078] The optional conductive material is electrochemically inactive and may be included in the positive electrode 24 to provide sufficient conductivity to the positive electrode 24 to support electron penetration therein. Examples of conductive materials include carbon-based materials, metals (e.g., nickel), and / or conductive polymers. Examples of conductive carbon-based materials include carbon black (CB) (e.g., acetylene black), graphite, graphene (e.g., graphene nanosheets, GNPs), graphene oxide, carbon nanotubes (CNTs), and / or carbon fibers (e.g., carbon nanofibers). Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, and / or polypyrrole. When included in the positive electrode 24, the optional conductive material may account for greater than 0%, optionally greater than or equal to about 1%, or optionally greater than or equal to about 5% and less than or equal to about 10% by weight of the positive electrode 24.

[0079] The separator 26 physically separates and electrically isolates the negative electrode 22 and the positive electrode 24 from each other while allowing lithium ions to pass through. The separator 26 has an open microporous structure and may include organic and / or inorganic materials. For example, the separator 26 may include a polymer or a combination of polymers. For example, the separator 26 may include one or more polyolefins, such as polyethylene (PE), polypropylene (PP), polyamide (PA), poly(tetrafluoroethylene) (PTFE), polyvinylidene fluoride (PVDF) and / or poly(vinyl chloride) (PVC). In one form, the separator 26 may include a laminate of polymers, such as a laminate of PE and PP. In one aspect, the separator 26 may include a ceramic coating (not shown) disposed on one or both sides thereof. In such a case, the ceramic coating may include aluminum oxide (Al 2 O 3 ) and / or silicon dioxide (SiO 2) particles. The separator 26 may have a thickness of greater than or equal to about 5 micrometers (μm), optionally greater than or equal to about 10 μm, or optionally greater than or equal to about 20 μm and less than or equal to about 500 μm, optionally less than or equal to about 200 μm, or optionally less than or equal to about 50 μm. The separator 26 may have a porosity of greater than or equal to about 20%, optionally greater than or equal to about 30% and less than or equal to about 80%, or optionally less than or equal to about 70%.

[0080] The electrolyte 28 is ionically conductive and provides a medium for conducting lithium ions between the negative electrode 22 and the positive electrode 24. The electrolyte 28 permeates the positive electrode 24, the separator 26, and the composite interlayer 38, and wets the facing surface 40 of the negative electrode 22. The electrolyte 28 includes an organic solvent and a lithium salt in the organic solvent.

[0081] The organic solvent of the electrolyte 28 may include a non-aqueous aprotic organic solvent. Non-limiting examples of non-aqueous aprotic organic solvents include cyclic carbonates (e.g., ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), and vinylene carbonate (VC)); linear carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)); aliphatic carboxylates (e.g., methyl formate, methyl acetate, methyl propionate); lactones (e.g., γ-butyrolactone, γ-valerolactone, and / or δ-valerolactone); nitriles (e.g., succinonitrile, glutaraldehyde, butylene carbonate ... nitriles and / or adiponitrile); sulfones (e.g., tetramethylene sulfone, ethyl methyl sulfone, vinyl sulfone, phenyl sulfone, 4-fluorophenyl sulfone, benzyl sulfone and / or cyclopentane sulfone); aliphatic ethers (e.g., triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dimethoxypropane, 1,2-dimethoxyethane, 1,2-diethoxyethane and / or ethoxymethoxyethane); cyclic ethers (e.g., 1,4-dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane); phosphates (e.g., triethyl phosphate and / or trimethyl phosphate); and combinations thereof. In aspects, the organic solvent may include a mixture of cyclic carbonates and linear carbonates. The organic solvent may account for greater than or equal to about 80%, or optionally greater than or equal to about 85%, and less than or equal to about 95%, or optionally less than or equal to about 90%, by weight of the electrolyte 28.

[0082] The lithium salt of the electrolyte 28 is soluble in an organic solvent and provides a path for lithium ions to pass through the electrolyte 28. The lithium salt may include an inorganic lithium salt, an organic lithium salt, or a combination thereof. Examples of inorganic lithium salts include lithium hexafluorophosphate (LiPF 6 ), lithium difluorophosphate (LiPO 2 F 2 ),

[0083] Lithium perchlorate (LiClO 4), lithium tetrachloroaluminate (LiAlCl 4 ), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF 4 ) lithium hexafluoroarsenate (LiAsF 6 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), Lithium Bis(trifluoromethane)sulfonyl imide (LiN(CF 3 SO 2 ) 2 ), Lithium Bis(FSO 2 ) 2 )(LiFSI), lithium tetraphenylborate (LiB(C 6 H 5 ) 4 ), lithium bis(oxalato)borate (LiB(C 2 O 4 ) 2 )(LiBOB), lithium difluoro(oxalato)borate (LiBF 2 (C 2 O 4 ))(LiDFOB) and combinations thereof. In one aspect, the lithium salt may include LiPF 6 The lithium salt may be dissolved in the organic solvent at a concentration of greater than or equal to about 0.5 moles / liter (mol / L or Molar) and less than or equal to about 1.5 Molar. In aspects, the lithium salt may be dissolved in the organic solvent at a concentration of about 1 Molar. The lithium salt may comprise greater than or equal to about 5%, optionally greater than or equal to about 10% and less than or equal to about 20%, or optionally less than or equal to about 15% by weight of the electrolyte 28.

[0084] The negative electrode current collector and the positive electrode current collector 30, 32 are conductive and provide electrical connections between the external circuit 36 ​​and their respective positive and negative electrodes 22, 24. In one aspect, the negative electrode current collector and the positive electrode current collector 30, 32 can be in the form of a non-porous metal foil, a perforated metal foil, a porous metal mesh, or a combination thereof. The negative electrode current collector 30 can be made of copper, nickel, or alloys thereof, stainless steel, or other suitable conductive materials. The positive electrode current collector 32 can be made of aluminum (Al) or another suitable conductive material.

[0085] The composite interlayer 38 is electrically insulating and ionically conductive and is configured to help prevent undesirable chemical reactions between the electrolyte 28 and the negative electrode 22 without hindering the flow of lithium ions between the electrolyte 28 and the negative electrode 22. The composite interlayer 38 has an open microporous structure and is disposed on the facing surface 40 of the negative electrode 22, between the first side 44 of the separator 26. The composite interlayer 38 may have a porosity greater than or equal to about 20%, optionally greater than or equal to about 30% and less than or equal to about 80%, or optionally less than or equal to about 70%. The composite interlayer 38 includes a polymer matrix phase and a lithium salt dispersed phase embedded in the polymer matrix phase of the composite interlayer 38 and substantially uniformly dispersed throughout the polymer matrix phase.

[0086] The polymer matrix phase is configured to provide good mechanical strength and flexibility to the composite interlayer 38 and to help retain, entrap or fix the lithium salt dispersed phase in the composite interlayer 38. The polymer matrix phase includes a polymer. For example, the polymer matrix phase may include poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly (ethylene oxide) (PEO), poly (acrylic acid) (PAA), poly (methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), poly (vinyl alcohol) (PVA), polyvinyl pyrrolidone (PVP) or a combination thereof. The polymer matrix phase may account for greater than or equal to about 50% and less than or equal to about 90% by weight of the composite interlayer 38.

[0087] The lithium salt dispersed phase contains a lithium salt and provides the composite interlayer 38 with a relatively high lithium salt concentration compared to the rest of the battery 20, such as the lithium salt concentration in the electrolyte 28. The lithium salt dispersed phase is entrapped or fixed in the polymer matrix phase of the composite interlayer 38 so that the lithium salt dispersed phase is not dissolved or released from the composite interlayer 38 when the composite interlayer 38 is penetrated by the electrolyte 28. The lithium salt of the lithium salt dispersed phase may include lithium bis(fluorosulfonyl)imide (LiN(FSO 2 ) 2 )(LiFSI), lithium trifluoromethanesulfonate (LiCF 3 SO 3 )(LiOTf), lithium bis(perfluoroethane)sulfonyl imide (Li(CF 3 CF 2 SO 2 ) 2 N) (LiBETI), lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide (LiDMSI), cyclohexafluoropropane-1,1-bis(sulfonyl)imide (LiHPSI), or a combination thereof. The lithium salt dispersed phase may include the same lithium salt as the lithium salt contained in the electrolyte 28 or a different lithium salt.

[0088] The lithium salt dispersed phase may comprise greater than or equal to about 10%, optionally greater than or equal to about 15%, optionally greater than or equal to about 20%, optionally greater than or equal to about 25%, optionally greater than or equal to about 30%, optionally greater than or equal to about 35%, optionally greater than or equal to about 40%, or optionally greater than or equal to about 45% and less than or equal to about 50% by weight of the composite interlayer 38. The lithium salt dispersed phase concentration in the composite interlayer 38 may be greater than or equal to about 1 mol / dm 3 ), optionally greater than or equal to about 1.5 mol / dm 3 , optionally greater than or equal to about 2 mol / dm 3 , optionally greater than or equal to about 2.5 mol / dm 3 , optionally greater than or equal to about 3 mol / dm 3 , optionally greater than or equal to about 3.5 mol / dm 3 , optionally greater than or equal to about 4 mol / dm 3 , or optionally greater than or equal to about 4.5 mol / dm 3 and less than or equal to about 10 mol / dm 3 .

[0089] The lithium salt dispersed phase in the composite interlayer 38 creates a locally high lithium salt concentration along the facing surface 40 of the negative electrode 22 compared to the lithium salt concentration in the electrolyte 28. In other words, the lithium salt concentration in the composite interlayer 38 is higher than the lithium salt concentration in the electrolyte 28. In turn, the lithium salt concentration in the composite interlayer 38 is also higher than the lithium salt concentration in the separator 26 that is infiltrated by the electrolyte 28. Without intending to be bound by theory, it is believed that creating a locally high lithium salt concentration along the facing surface 40 of the negative electrode 22 may increase the coordination of lithium ions (Li ions) in the electrolyte 28 along the facing surface 40 of the negative electrode 22. + ) thereby reducing the number of free organic solvent molecules in the electrolyte 28 that can be reduced at the negative electrode 22.

[0090] The composite interlayer 38 creates a mechanically robust interface between the negative electrode 22 and the electrolyte 28, which helps prevent undesirable reactions between the negative electrode 22 and the electrolyte 28 during repeated cycling of the battery 20. In addition, the interface established between the negative electrode 22 and the electrolyte 28 by the composite interlayer 38 can be maintained during repeated cycling of the battery 20 without causing undesirable consumption of the electrolyte 28 and / or undesirable consumption of active lithium in the battery 20, which can increase the cycle life of the battery 20. In addition, without intending to be bound by theory, it is believed that the composite interlayer 38 may help inhibit the formation of lithium dendrites on the facing surface 40 of the negative electrode 22, such as by creating a robust physical barrier to hinder the growth of lithium dendrites at or on the negative electrode 22. In addition, it is believed that the composite interlayer 38 may help promote uniform deposition of lithium metal on the negative electrode current collector 30.

[0091] method

[0092] The composite intermediate layer 38 may be manufactured by depositing a precursor solution on a substrate to form a precursor layer, and then drying the precursor layer.

[0093] The precursor solution may include an organic solvent, a polymer, and a lithium salt dissolved in the organic solvent. The polymer in the precursor solution may have a composition substantially the same as the polymer matrix phase in the composite interlayer 38, and may account for greater than or equal to about 15% and less than or equal to about 70% by weight of the precursor solution. The lithium salt in the precursor solution may have a composition substantially the same as the lithium salt dispersed phase in the composite interlayer 38, and may account for greater than or equal to about 3%, or optionally greater than or equal to about 5% and less than or equal to about 15%, or optionally less than or equal to about 10% by weight of the precursor solution. The organic solvent in the precursor solution may have a boiling point greater than or equal to about 80° C. and less than about 180° C. Examples of organic solvents having a boiling point in this range include acetonitrile (ACN), N-methyl-2-pyrrolidone (NMP), methoxymethane (DME), dimethyl carbonate (DMC), dimethylformamide (DMF), or a combination thereof. The organic solvent may comprise greater than or equal to about 20% and less than or equal to about 80% by weight of the precursor solution.

[0094] In one aspect, the substrate can be made of plastic or glass. For example, the substrate can be made of polyethylene terephthalate (PET). In other aspects, the substrate can include the same material as the negative electrode 22.

[0095] The precursor solution can be deposited on the substrate by any suitable method. For example, the precursor solution can be deposited on the substrate using a tape casting technique.

[0096] After forming the precursor layer on the substrate, the organic solvent is removed from the precursor layer to form the composite interlayer 38. The organic solvent can be removed from the precursor layer, for example, by evaporation. For example, the organic solvent can be removed from the precursor layer by heating the precursor layer at a temperature of about 60° C. for about 12 hours to evaporate the organic solvent therefrom.

[0097] In aspects where the substrate comprises the same material as the negative electrode 22, the substrate and composite interlayer 38 can be combined with other necessary components and assembled into the battery 20. In aspects where the substrate is made of plastic or glass, the composite interlayer 38 can be peeled from the substrate. The composite interlayer 38 is then placed or applied to the surface of the lithium metal layer and assembled into the battery 20, where the lithium metal layer can define the negative electrode 22.

[0098] The foregoing description is merely exemplary and is absolutely not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited thereto, because after studying the drawings, the specification and the following claims, other modifications will become apparent. It should be understood that one or more steps in the method may be implemented in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more features described with respect to any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and the mutual replacement of one or more embodiments is still within the scope of the present disclosure.

[0099] The terms used herein are intended to be limited only for the purpose of describing exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one" and "the" used herein are intended to also include plural forms. The terms "comprising", "including" and "having" are inclusive, and therefore specify the presence of specified features, elements, compositions, steps, integers, operations and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations. Although the open terms "comprising", "including" and "having" should be understood as non-limiting terms for describing and requesting the various embodiments described herein, in some aspects, these terms are understood as more restrictive and constraining terms, such as "consisting of..." or "consisting essentially of..." Therefore, for any given embodiment of a composition, material, component, element, ingredient, feature, integer, operation and / or method step, the present disclosure also clearly includes an embodiment consisting of or essentially consisting of these enumerated compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps. In the case of “consisting of,” the alternative embodiment does not include any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps, while in the case of “consisting essentially of,” such an embodiment does not include any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps that substantially affect the basic and novel characteristics, but may include any compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps that do not substantially affect the basic and novel characteristics in the embodiment.

[0100] Any method steps, methods, and operations described herein are not to be construed as necessarily requiring their performance in the order discussed or illustrated, unless expressly specified as an order of performance. It is also to be understood that additional or alternative steps may be used unless otherwise specified.

[0101] When a component, element, or layer is referred to as being "on," "engaged," "connected," or "coupled" to another element or layer, it may be directly on, directly engaged, connected, or coupled to, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). The term "and / or" as used herein includes a combination of one or more related enumerated items.

[0102] Although the terms first, second, third, etc. may be used in this article to describe various steps, elements, components, regions, layers and / or sections, unless otherwise specified, these steps, elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other ordinal terms do not imply order or sequence when used in this article. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section without departing from the teaching of exemplary embodiments.

[0103] For ease of description, spatially or temporally relative terms such as "front", "rear", "inside", "outside", "lower", "below", "lower", "upper", etc. may be used herein to describe the relationship of one element or component to another element or component as shown in the drawings. The spatially or temporally relative terms are intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the drawings.

[0104] Throughout this disclosure, numerical values ​​represent approximate measurements or range limits, and include slight deviations from given values ​​and embodiments that have approximately the listed values ​​as well as embodiments that have exactly the listed values. In addition to the examples provided at the end of the specific embodiments, all numerical values ​​of parameters (such as amounts or conditions) in this specification should be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. The numerical values ​​of the parameters in the attached claims should be understood to be modified by the term "about" only when the term "about" appears before the numerical value. "Approximately" means that the specified numerical value allows a certain slight imprecision (close to the accuracy of the value; approximately or reasonably close to the value; almost). If the imprecision provided by "approximately" is not understood in this ordinary sense in the art, "approximately" used herein at least refers to changes that may be caused by ordinary methods of measuring and using such parameters. For example, "approximately" may include changes of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects, optionally less than or equal to 0.1%. Additionally, disclosure of ranges includes disclosure of all values ​​within the entire range and further subdivided ranges, including endpoints and subranges given within those ranges.

[0105] As used herein, unless otherwise indicated, the terms "composition" and "material" are used interchangeably to refer generally to materials that contain at least a preferred chemical component, element, or compound, but may also contain additional elements, compounds, or substances, including trace impurities. An "X-based" composition or material generally refers to a composition or material in which "X" is the single largest component of the composition or material on a weight percent (%) basis. This can include compositions or materials having greater than 50% by weight of X, and can also include compositions or materials having less than 50% by weight of X, as long as X is the single largest component of the composition or material based on its total weight. When a composition or material is referred to as being "substantially free" of a substance, the composition or material may contain less than 5%, optionally less than 3%, optionally less than 1%, or optionally less than 0.1% by weight of the substance.

[0106] As used herein, the term "metal" may refer to a pure elemental metal, or to an alloy of an elemental metal and one or more other metals or nonmetallic elements, referred to as "alloying" elements. Alloying elements may be selected to impart certain desirable properties to the alloy that are not exhibited by the base metal element.

Claims

1. A battery pack for circulating lithium ions, the battery pack comprising: Lithium metal negative electrode; a positive electrode spaced apart from a negative lithium metal electrode, the positive electrode comprising an electroactive positive electrode material, the negative lithium metal electrode and the positive electrode having opposing facing surfaces; a porous separator disposed between opposing facing surfaces of the lithium metal negative electrode and the positive electrode, the porous separator having a first side facing the lithium metal negative electrode and an opposite second side facing the positive electrode; a composite interlayer disposed on a facing surface of a lithium metal negative electrode and between the lithium metal negative electrode and a porous separator, the composite interlayer comprising a polymer matrix phase and a lithium salt dispersed phase embedded in and dispersed throughout the polymer matrix phase, the lithium salt dispersed phase accounting for greater than or equal to about 10% and less than or equal to about 50% by weight of the composite interlayer; and an electrolyte that wets the facing surface of the lithium metal negative electrode and penetrates the porous separator and the composite interlayer, the electrolyte comprising an organic solvent and a lithium salt, The lithium salt concentration in the electrolyte is less than the lithium salt concentration in the composite intermediate layer.

2. The battery of claim 1, wherein the polymer matrix phase comprises at least one polymer selected from the group consisting of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), poly(acrylic acid) (PAA), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), poly(vinyl alcohol) (PVA) and polyvinyl pyrrolidone (PVP).

3. The battery of claim 1, wherein the polymer matrix phase comprises poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP).

4. The battery according to claim 1, wherein the lithium salt dispersed phase comprises at least one lithium salt selected from lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTf), lithium bis(perfluoroethane)sulfonyl imide (LiBETI), lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide (LiDMSI) and cyclohexafluoropropane-1,1-bis(sulfonyl)imide (LiHPSI). 5 . The battery of claim 1 , wherein the lithium salt dispersed phase comprises lithium bis(fluorosulfonyl)imide (LiFSI).

6. The battery of claim 1, wherein the electrolyte has a lithium salt concentration of about 1 mol / L, and wherein the composite interlayer has a lithium salt concentration greater than or equal to about 2 mol / dm3. 7 . The battery pack according to claim 1 , wherein the lithium salt dispersed phase is fixed in the polymer matrix phase of the composite interlayer so that the lithium salt dispersed phase is not released from the composite interlayer when the composite interlayer is penetrated by the electrolyte.

8. The battery of claim 1 , wherein the composite interlayer extends from a facing surface of the lithium metal negative electrode to a first side of the porous separator, and wherein the composite interlayer has a thickness greater than or equal to about 5 microns and less than or equal to about 50 microns.

9. The battery of claim 1, wherein the porous separator comprises a polyolefin and has a thickness of greater than or equal to about 5 microns and less than or equal to about 500 microns.

10. The battery of claim 1, wherein the lithium metal negative electrode comprises greater than 97% lithium by weight.

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