solid state batteries

Abstract

A solid-state battery is provided that includes a cathode, an anode, and a solid electrolyte. In one embodiment, the cathode, anode, and / or solid electrolyte are formed from a printable lithium composition comprising lithium metal powder, a polymeric binder compatible with the lithium metal powder, a rheology modifier compatible with the lithium metal powder, and a solvent compatible with the lithium metal powder and the polymeric binder. In another embodiment, lithium is deposited on the solid electrolyte by a printable lithium composition of lithium comprising lithium metal powder, a polymeric binder compatible with the lithium metal powder, a rheology modifier compatible with the lithium metal powder, and a solvent compatible with the lithium metal powder and the polymeric binder.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS The following application claims priority to U.S. Patent Application No. 16 / 359,707 (standard application), filed March 20, 2019, U.S. Patent Application No. 16 / 359,725 (standard application), filed March 20, 2019, U.S. Patent Application No. 16 / 359,733 (standard application), filed March 20, 2019, U.S. Provisional Patent Application No. 62 / 646,521 filed March 22, 2018, and U.S. Provisional Patent Application No. 62 / 691,819 filed June 29, 2018, the disclosures of which are incorporated by reference in their entireties.

[0002] The present invention relates to solid-state batteries that include printable lithium compositions. [Background technology]

[0003] Lithium and lithium-ion secondary or rechargeable batteries are found in certain applications such as mobile phones, camcorders, laptop computers, and more recently in high power applications such as electric and hybrid electric vehicles. In these applications, it is preferable for secondary batteries to have as high a specific capacity as possible, yet also provide safe operating conditions and good cyclability so that the high specific capacity is maintained upon subsequent recharge and discharge cycles.

[0004] Secondary batteries come in a variety of configurations, each of which includes a positive electrode (or cathode), a negative electrode (or anode), a separator separating the cathode and anode, and an electrolyte in electrochemical communication between the cathode and anode. For secondary lithium batteries, when the secondary battery is being discharged, i.e., used in a particular application, lithium ions migrate from the anode to the cathode through the electrolyte. During the discharge process, electrons are collected from the anode and sent to the cathode through an external circuit. When the secondary battery is being charged or recharged, lithium ions migrate from the cathode to the anode through the electrolyte.

[0005] Historically, secondary lithium batteries were manufactured using delithiated compounds with high specific capacities, such as TiS2, MoS2, MnO2, and V2O5, as cathode active materials. These cathode active materials were bonded to a lithium metal anode. When the secondary battery was discharged, lithium ions migrated from the lithium metal anode to the cathode through the electrolyte. Unfortunately, upon cycling, the lithium metal developed dendrites, which ultimately posed a dangerous threat to the battery. As a result, production of these types of secondary batteries ceased in the early 1990s in favor of lithium-ion batteries.

[0006] Lithium-ion batteries typically use lithium metal oxides, such as LiCoO2 or LiNiO2, as the cathode active material combined with an active anode material, such as a carbon-based material. It is recognized that there are other types of anodes based on silicon oxide, silicon particles, etc. In batteries utilizing a carbon-based anode system, the formation of lithium dendrites at the anode is substantially avoided, thereby making the battery safer. However, the amount of lithium determines the capacity of the battery, and all of the lithium is supplied by the cathode. This limits the choice of cathode active material, as the active material must contain removable lithium. Also, the formation of Li during charging and overcharging is a problem. x CoO2, Li xDelithiated versions of NiO2 are not stable, and in particular, these delithiated versions tend to react with the electrolyte and generate heat, raising safety concerns.

[0007] A new lithium-ion cell or battery is initially in a discharged state. During the first charge of a lithium-ion cell, lithium migrates from the cathode material to the anode active material. The lithium that migrates from the cathode to the anode reacts with the electrolyte material on the surface of the graphite anode, forming a passivation film on the anode. The passivation film formed on the graphite anode is the solid electrolyte interface (SEI). During subsequent discharges, the lithium consumed by the formation of the SEI is not returned to the cathode. This results in a lithium-ion cell with a reduced capacity compared to its initial charge capacity because some of the lithium was consumed by the formation of the SEI. The partial consumption of available lithium during the first cycle reduces the capacity of the lithium-ion cell. This phenomenon, called irreversible capacity, is known to consume approximately 10% to 20% or more of the capacity of a lithium-ion battery. Therefore, after the initial charge of a lithium-ion cell, the lithium-ion cell loses approximately 10% to 20% or more of its capacity.

[0008] One solution is to pre-lithiate the anode using stabilized lithium metal powder. For example, lithium powder can be stabilized by passivating the metal powder surface with carbon dioxide, as described in U.S. Patent Nos. 5,567,474, 5,776,369, and 5,976,403, the disclosures of which are incorporated herein by reference in their entireties. CO2-passivated lithium metal powder can only be used in low-moisture air for a limited period before the lithium metal content decreases due to reaction between the lithium metal and air. Another solution is to apply a coating such as fluorine, wax, phosphorus, or polymer to the lithium metal powder, as described in U.S. Patent Nos. 7,588,623, 8,021,496, 8,377,236, and U.S. Patent Publication No. 2017 / 0149052.

[0009] However, there is still a need for solid-state batteries with lithiated or prelithiated components to increase energy density and improve safety and manufacturability. Summary of the Invention [Problem to be solved by the invention]

[0010] To this end, the present invention provides solid-state batteries having one or more components that are prelithiated, i.e., lithiated with a printable lithium composition. Solid-state batteries containing printable lithium compositions offer increased energy density, improved safety, and manufacturability. [Means for solving the problem]

[0011] The printable lithium composition of the present invention includes a lithium metal powder, a polymer binder, the polymer binder being compatible with the lithium powder, and the rheology modifier being compatible with the lithium powder and the polymer binder. The printable lithium composition can include a solvent, the solvent being compatible with the lithium powder and compatible with (e.g., capable of forming a suspension or dissolving) the polymer binder. The solvent can be included as an ingredient during the initial preparation of the printable lithium composition, or can be added after the printable lithium composition is prepared. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a solid-state battery according to one embodiment of the present invention.

[0013] [Figure 2] 10 is a temperature and pressure profile for reactivity testing of SLMP / styrene butadiene / toluene printable lithium compositions.

[0014] [Figure 3] 10 is a plot showing the cycling performance of a pouch cell with a thin lithium film derived from printable lithium as the anode versus a pouch cell with a commercially available thin lithium foil. DETAILED DESCRIPTION OF THE INVENTION

[0015] The foregoing and other aspects of the present invention will now be explained in more detail with reference to the descriptions and methodologies provided herein. It is understood that the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0016] The terms used in the description of the present invention herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the present invention. When used in describing embodiments of the present invention and in the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Also, as used herein, "and / or" denotes and encompasses any and all possible combinations of one or more of the associated listed items.

[0017] When used herein to refer to measurable values ​​such as the amount of a compound, dosage, time, temperature, etc., the term "about" is intended to include variables of 20%, 10%, 5%, 1%, 0.5%, or even 0.1% of the specified amount. Unless otherwise defined, all terms, including technical and scientific terms, used in the description have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0018] As used herein, the terms "comprise", "comprises", "comprising", "include", "includes" and "including" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0019] As used herein, the term "consists essentially of" (and grammatical variations thereof) as applied to the compositions and methods of the present invention means that the composition / method may include additional components so long as the additional components do not materially alter the composition / method. The term "materially alter" as applied to a composition / method refers to an increase or decrease in the effectiveness of the composition / method by at least about 20% or more.

[0020] All patents, patent applications, and publications mentioned herein are incorporated by reference in their entirety. In the event of a conflict in terminology, the present specification will control.

[0021] Referring now to FIG. 1 , in accordance with one embodiment of the present invention, a solid-state battery 10 is provided that includes an anode 12, a cathode 14, and a solid electrolyte 16. The solid-state battery may further include an anode current collector 20 and a cathode current collector 22. The printable lithium composition is applied or deposited onto the current collector, electrode, and / or solid electrolyte of the solid-state battery. For example, the printable lithium composition can be used to form monolithic lithium metal anodes of various thicknesses and widths for use in solid-state batteries, including the solid-state batteries described in U.S. Pat. Nos. 8,252,438 and 9,893,379, which are incorporated herein by reference in their entireties. In yet another embodiment, the printable lithium composition can be applied or deposited to form a solid electrolyte for a solid-state battery and includes a combination of an ink composition and a polymeric or ceramic material to form the solid electrolyte. The printable lithium composition includes lithium metal powder, one or more polymeric binders, one or more rheology modifiers, and may further include a solvent or co-solvent.

[0022] The printable lithium composition can be applied to a current collector, electrode, or solid electrolyte by a variety of methods, including extrusion, coating, printing, painting, dipping, and spraying, as disclosed in U.S. Patent Application Publication No. __________ (Attorney Docket No. 073396.1183, filed concurrently herewith and incorporated by reference in its entirety). For example, an anode can be lithiated or prelithiated by printing the printable lithium composition onto the anode or current collector, which can form a thin lithium film of controlled thickness and width, or by coating the anode with the printable lithium composition.

[0023] In one embodiment, the printable lithium composition can be used for prelithiation of a solid electrolyte, as described in U.S. Patent No. 7,914,930, which is incorporated herein by reference in its entirety. An example of a solid-state secondary battery can include a positive electrode capable of electrochemically absorbing and desorbing lithium, a negative electrode capable of electrochemically absorbing and desorbing lithium, the negative electrode including an active material layer including an active material, the active material layer being supported on a current collector, and a non-aqueous electrolyte. The method includes contacting the printable lithium composition with a surface of the active material layer of the negative electrode, thereby reacting lithium with the active material of the negative electrode, and then combining the negative electrode with a positive electrode to form an electrode assembly.

[0024] As disclosed in U.S. Patent Application Publication No. __________ (Attorney Docket No. 073396.1116, filed concurrently herewith), which is incorporated by reference in its entirety, printable lithium compositions include lithium metal powder, a polymer binder, a rheology modifier, and may further include a solvent. The polymer binder may be compatible with the lithium metal powder. The rheology modifier may be compatible with the lithium metal powder and the polymer binder. The solvent may be compatible with the lithium metal powder and the polymer binder.

[0025] It may be in the form of a finely divided powder. Lithium metal powders typically have an average particle size of less than about 80 microns, often less than about 40 microns, and sometimes less than about 20 microns. The lithium metal powder may be stabilized lithium metal powder with low pyrophoricity (SLMP®), available from FMC. The lithium metal powder may also include a substantially continuous layer or coating of fluorine, wax, phosphorus, or a polymer, or a combination thereof (as disclosed in U.S. Pat. Nos. 5,567,474, 5,776,369, and 5,976,403). Lithium metal powders have significantly reduced reactivity with moisture and air.

[0026] Lithium metal powder can also be alloyed with metals. For example, lithium metal powder can be alloyed with Group I-VIII elements. Suitable elements from Group IB can include, for example, copper, silver, or gold. Suitable elements from Group IIB can include, for example, zinc, cadmium, or mercury. Suitable elements from Group IIA of the periodic table can include, for example, beryllium, magnesium, calcium, strontium, barium, and radium. Suitable elements from Group IIIA that can be used in the present invention can include, for example, boron, aluminum, gallium, indium, or thallium. Suitable elements from Group IVA that can be used in the present invention can include, for example, carbon, silicon, germanium, tin, or lead. Suitable elements from Group VA that can be used in the present invention can include, for example, nitrogen, phosphorus, or bismuth. Suitable elements from Group VIIIB can include, for example, nickel, palladium, or platinum.

[0027] The polymer binder is selected to be compatible with the lithium metal powder. "Compatible with" or "compatibility" means that the polymer binder does not react violently with the lithium metal powder to create a safety hazard. The lithium metal powder and the polymer binder can react to form a lithium-polymer composite, but such a composite must be stable at various temperatures. It is recognized that the amount (concentration) of lithium and polymer binder contributes to stability and reactivity. The polymer binder can have a molecular weight of about 1,000 to about 8,000,000, and often has a molecular weight of 2,000,000 to 5,000,000. Suitable polymer binders can include one or more of poly(ethylene oxide), polystyrene, polyisobutylene, natural rubber, butadiene rubber, styrene butadiene rubber, polyisoprene rubber, butyl rubber, hydrogenated nitrile butadiene rubber, epichlorohydrin rubber, acrylate rubber, silicon rubber, nitrile rubber, polyacrylic acid, polyvinylidene chloride, polyvinyl acetate, ethylene propylene diene termonomer, ethylene vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene terpolymer, polybutene. The binder can also be a wax.

[0028] The rheology modifier is selected to be compatible with the lithium metal powder and the polymer binder. The rheology modifier provides rheological properties such as viscosity. Depending on the selection of the rheology modifier, the rheology modifier may also provide conductivity, improved capacity, and / or improved stability / safety. To this end, the rheology modifier may be a combination of two or more compounds to provide different or additional properties. Exemplary rheology modifiers may include one or more of carbon black, carbon nanotubes, graphene, silicon nanotubes, graphite, hard carbon and mixtures, fumed silica, titanium dioxide, zirconium dioxide, and other Group IIA, IIIA, IVB, VB, and VIA elements / compounds, and mixtures or formulations thereof.

[0029] Solvents compatible with lithium can include acyclic hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, symmetrical ethers, asymmetrical ethers, cyclic ethers, alkanes, sulfones, mineral oils, and mixtures, blends, or cosolvents thereof. Examples of suitable acyclic and cyclic hydrocarbons include n-hexane, n-heptane, cyclohexane, and the like. Examples of suitable aromatic hydrocarbons include toluene, ethylbenzene, xylene, isopropylbenzene (cumene), and the like. Examples of suitable symmetrical, asymmetrical, and cyclic ethers include di-n-butyl ether, methyl t-butyl ether, tetrahydrofuran, glyme, and the like. Commercially available isoparaffinic synthetic hydrocarbon solvents with adjusted boiling ranges, such as Shell Sol® (Shell Chemicals) or Isopar® (Exxon), are also suitable.

[0030] The polymer binder and solvent are selected to be compatible with each other and with the lithium metal powder. Generally, the binder or solvent should not react with the lithium metal powder, or should be present in an amount such that any reaction is kept to a minimum and violent reactions are avoided. The binder and solvent should be compatible with each other at the temperatures at which the printable lithium composition will be made and used. Preferably, the solvent (or co-solvent) is sufficiently volatile to readily evaporate from the printable lithium composition (e.g., in slurry form) to provide for drying of the printable lithium composition (slurry) after application.

[0031] The components of the printable lithium composition can be mixed together as a slurry or paste to have a high concentration of solids. Thus, the slurry / paste can be in the form of a concentrate to which not all of the solvent is added prior to deposition or application. In one embodiment, the lithium metal powder should be uniformly suspended in the solvent so that, upon application or deposition, a substantially uniform distribution of lithium metal powder is deposited or applied. The dry lithium powder can be dispersed, such as by vigorous stirring or agitation, to apply high shear forces.

[0032] In another embodiment, a mixture of polymer binders, rheology modifiers, coating agents, and other potential additives for the lithium metal powder can be formed and introduced to contact the lithium droplets during dispersion at a temperature above the lithium melting point, or at a lower temperature after the lithium dispersion has cooled, as described in U.S. Pat. No. 7,588,623, the disclosure of which is incorporated by reference in its entirety. The lithium metal thus modified can be introduced in crystalline form or in solution in a selected solvent. It should be understood that different combinations of process parameters can be used to achieve specific coating and lithium powder properties for specific applications.

[0033] Conventional prelithiation (prelithiation) surface treatments require compositions with very low binder content and very high lithium content; see, for example, U.S. Pat. No. 9,649,688, the disclosure of which is incorporated by reference in its entirety. However, embodiments of printable lithium compositions according to the present invention can accommodate higher binder ratios, including up to 20 percent dry basis. Various properties of printable lithium compositions, such as viscosity and flow, can be modified by increasing the binder and modifier content up to 50% dry basis without losing the electrochemical activity of the lithium. Increasing the binder content facilitates flow during loading and printing of the printable lithium composition. For example, in one embodiment, the printable lithium composition comprises about 70% lithium metal powder and about 30% polymer binder and rheology modifier. In another embodiment, the printable lithium composition can comprise about 85% lithium metal powder and about 15% polymer binder and rheology modifier.

[0034] An important aspect of printable lithium compositions is the rheological stability of the suspension. Due to the low density of metallic lithium, 0.534 g / cc, it is difficult to prevent lithium powder separation from the solvent suspension. By selecting the lithium metal powder loading, the type and amount of polymer binder and conventional modifiers, viscosity and rheology can be tailored to produce stable suspensions of the present invention. Preferred embodiments do not exhibit separation for more than 90 days. This is consistent with the rheological stability of 1×10 4 cps~1×10 7 This can be achieved by designing a composition with a very high zero shear viscosity in the cps range, however, it is critical to the application process that the composition exhibits viscosity characteristics in the claimed range when exposed to shear.

[0035] The resulting printable lithium composition is preferably 10s -1The printable lithium compositions preferably have a viscosity of about 20 to about 20,000 cps, often about 100 to about 10,000 cps. At such viscosities, the printable lithium compositions are flowable suspensions or gels. The printable lithium compositions preferably have a longer shelf life at room temperature and are stable to metallic lithium loss at temperatures up to 60°C, often up to 120°C, and sometimes up to 180°C. The printable lithium compositions may separate somewhat over time, but can be resuspended with gentle agitation and / or heating.

[0036] In one embodiment, the printable lithium composition is solution-based and includes approximately 5-50 percent lithium metal powder, approximately 0.1-20 percent polymer binder, approximately 0.1-30 percent rheology modifier, and approximately 50-95 percent solvent. In one embodiment, the printable lithium composition is solution-based and includes approximately 15-25 percent lithium metal powder, approximately 0.3-0.6 percent polymer binder having a molecular weight of 4,700,000, approximately 0.5-0.9 percent rheology modifier, and approximately 75-85 percent solvent. Typically, the printable lithium composition is applied or deposited to a thickness of approximately 50 microns to 200 microns before pressing. After pressing, the thickness can be reduced to approximately 1-50 microns. Examples of pressing techniques are described, for example, in U.S. Patent Nos. 3,721,113 and 6,232,014, which are incorporated herein by reference in their entireties.

[0037] In one embodiment, the printable lithium composition is deposited or applied to an active anode material on a current collector, i.e., forming a prelithiated anode. Suitable active anode materials include graphite and other carbon-based materials, alloys such as tin / cobalt, tin / cobalt / carbon, and silicon-carbon, various silicon / tin-based composite compounds, germanium-based composites, titanium-based composites, and elemental silicon and germanium. The anode material can be a foil, mesh, or foam. Application can be by spraying, extruding, coating, printing, painting, dipping, and atomization, as described in co-filed and co-pending U.S. Patent Application Publication No. ____________ (Attorney Docket No. 073396.1183), which is incorporated herein by reference in its entirety.

[0038] In one embodiment, the active anode material and the printable lithium composition are provided together and extruded onto a current collector (e.g., copper, nickel, etc.). For example, the active anode material and the printable lithium composition can be mixed and co-extruded. Examples of active anode materials include graphite, graphite-SiO, graphite-SnO, SiO, hard carbon, and other lithium-ion battery and lithium-ion capacitor anode materials. In another embodiment, the active anode material and the printable lithium composition are co-extruded to form a layer of the printable lithium composition on the current collector. Deposition of the printable lithium composition, including the extrusion techniques described above, can include deposition in a variety of patterns (e.g., dots, stripes), thicknesses, widths, etc. For example, the printable lithium composition and the active anode material can be deposited as a series of stripes, as described in U.S. Patent Publication No. 2014 / 0186519, which is incorporated herein by reference in its entirety. The stripes form a 3D structure that expands the active anode material during lithiation. For example, silicon can expand 300-400% during lithiation. Such expansion potentially adversely affects the anode and its performance. By depositing printable lithium as thin stripes in the Y plane in an alternating pattern between silicon anode stripes, the silicon anode material can expand in the X plane, mitigating electrochemical polishing and loss of particle electrical contact. Thus, the printing method can provide a buffer for expansion. Another example in which printable lithium formulations are used to form anodes is coextrusion with a cathode and separator in layers to form solid-state batteries.

[0039] In one embodiment, a printable lithium composition can be used to prelithiate an anode, as described in U.S. Pat. No. 9,837,659, the entire contents of which are incorporated herein by reference. For example, this method includes depositing a layer of the printable lithium composition adjacent to the surface of a prefabricated / preformed anode. The prefabricated electrode includes an electroactive material. In certain variations, the printable lithium composition can be applied to a carrier / substrate via a deposition process. The carrier substrate onto which the printable lithium composition layer can be deposited can be selected from the group consisting of polymer films (e.g., polystyrene, polyethylene, polyethylene oxide, polyester, polypropylene, polypolytetrafluoroethylene), ceramic films, copper foil, nickel foil, or metal foams, by way of non-limiting example. Heat can then be applied to the printable lithium composition layer on the substrate or prefabricated anode. The printable lithium composition layer on the substrate or prefabricated anode can both be further compressed under pressure. The application of heat and, optionally, pressure, promotes lithium migration to the surface of the substrate or anode. In the case of transfer to a prefabricated anode, pressure and heat can result in mechanical lithiation, particularly if the prefabricated anode contains graphite. In this way, lithium migrates to the electrode and, due to favorable thermodynamics, becomes incorporated into the active material.

[0040] In further embodiments, at least a portion of the printable lithium composition can be provided to the anode active material prior to battery assembly. In other words, the anode can include a partially lithium-loaded silicon-based active material, the partially loaded active material having a selected degree of lithium loading, such as by intercalation / alloying.

[0041] In one embodiment, the printable lithium composition can be incorporated into a three-dimensional electrode structure, as described in U.S. Patent Application Publication No. 2018 / 0013126, which is incorporated herein by reference in its entirety. For example, the printable lithium composition can be incorporated into a three-dimensional porous anode, a porous current collector, or a porous polymer or ceramic film, and the printable lithium composition can be deposited therein.

[0042] In some embodiments, electrodes prelithiated with the printable lithium composition can be assembled into a cell with electrodes preloaded with lithium. A separator can be disposed between each electrode. Electrical current can be passed between the electrodes. For example, anodes prelithiated with the printable lithium composition of the present invention can be formed into secondary batteries as described in U.S. Pat. No. 6,706,447, the entire contents of which are incorporated herein by reference.

[0043] The cathode is typically formed from an active material bound to a carbonaceous material and a binder polymer. The active material used in the cathode is preferably a lithiated material. Preferably, delithiated materials such as MnO2, V2O5, MoS2, metal fluorides or mixtures thereof, sulfur, and sulfur composite materials can be used as the active material. However, lithiated materials that can be further lithiated, such as LiMn2O4 and LiMO2, where M is Ni, Co, or Mn, can also be used. Delithiated active materials are generally preferred because they have high specific capacity, low cost, a wide selection of cathode materials, and can provide increased energy and power in this configuration compared to conventional secondary batteries containing lithiated active materials.

[0044] example Example 1 10 g of styrene-butadiene rubber liquid (S-SBR Europrene Sol® 72613) was dissolved in 90 g of toluene (99% anhydrous, Sigma-Aldrich) by stirring at 21°C for 12 hours. 6 g of 10 wt% SBR (polymer binder) in toluene (solvent) was combined with 0.1 g of carbon black (Timcal Super P) (rheology modifier) ​​and 16 g of toluene and dispersed in a Thinky ARE 250 planetary mixer at 2000 rpm for 6 minutes. 9.3 g of stabilized lithium metal powder (SLMP®, Livent Corp.) with a 20-200 μm polymer coating and a d50 of 20 μm was added to this suspension and dispersed in the Thinky mixer at 1000 rpm for 3 minutes. The printable lithium was filtered through a 180 μm opening stainless steel mesh. The printable lithium suspension is then doctor-bladed onto a copper current collector to a wet thickness of 2 mil (approximately 50 μm). Figure 3 is a plot showing the cycling performance of a pouch cell with a thin lithium film derived from printable lithium versus a pouch cell with a commercially available thin lithium foil as the anode.

[0045] Example 2 10 g of ethylene propylene diene terpolymer (EPDM) (Dow Nordel IP 4725P) with a molecular weight of 135,000 was dissolved in 90 g of p-xylene (anhydrous 99%, Sigma Aldrich) by stirring at 21 °C for 12 hours. 6 g of 10 wt% EPDM (polymer binder) in p-xylene (solvent) was combined with 0.1 g of TiO (Evonik Industries) (rheology modifier) ​​and 16 g of toluene and dispersed in a Thinky ARE 250 planetary mixer at 2000 rpm for 6 minutes. 9.3 g of stabilized lithium metal powder (SLMP®, FMC Lithium Corp.) with a 20-200 μm polymer coating and a d50 of 20 μm was added to this suspension and dispersed in the Thinky mixer at 1000 rpm for 3 minutes. The printable lithium was then filtered through a 180 μm opening stainless steel mesh. The printable lithium composition is then doctor blade coated onto a copper current collector to a wet thickness of 2 mils (approximately 50 μm).

[0046] Shelf Life Stability Printable lithium compositions must be selected to ensure chemical stability over a long shelf life at room temperature and for shorter periods at elevated temperatures, such as during transportation and drying. The stability of printable lithium compositions was tested using calorimetry. 1.5 g of SLMP was added to a 10 ml Hastelloy ARC bomb sample container. 2.4 g of a 4% SBR binder solution was added to the container. The container was equipped with a 24 ohm resistive heater and thermocouple to monitor and control the sample temperature. The bomb sample was then loaded into a 350 ml containment vessel along with insulation. A Fauske Industries Advance Reactive Screening Systems Tool calorimeter was used to evaluate the compatibility of printable lithium solutions during a constant temperature ramp up to 190 °C. The temperature ramp rate was 2 °C / min, and the sample temperature was held at 190 °C for 60 minutes. The test was conducted under 200 psi argon pressure to prevent solvent boiling. FIG. 2 is a graph of temperature and pressure for reactivity testing of SLMP / styrene butadiene / toluene printable lithium compositions.

[0047] Printing performance The quality of a printable lithium composition with respect to printability is measured by several factors, such as flow constancy, which directly affects the ability to control the lithium loading onto the substrate or electrode surface. An effective way to measure flow is flow conductance, which is an expression of loading per square centimeter related to factors that control loading: pressure during extrusion and printer head speed. It can be most simply thought of as the inverse of flow resistance.

[0048] This display allows comparisons between prints with varying pressure and speed, and can alert us to nonlinear relationships between flow and pressure due to changes in flow conductance. These are important for scaling printable lithium loadings up or down depending on the needs of the anode or cathode. An ideal printable lithium composition would behave linearly with changes in extrusion pressure.

[0049] To test printability, the printable lithium composition was filtered through a 180 μm opening stainless steel mesh and loaded into a Nordson EFD 10 ml syringe. The syringe was loaded into a Nordson EFD HP4x syringe dispenser and attached to a slot-die printhead. The slot-die printhead was equipped with a 100 μm to 300 μm thick shim with channel openings designed to accommodate the loading of the printable lithium composition. The slot-die head was attached to a Loctite 300 series robot. The printhead speed was set to 200 mm / s, and the print pressure was 20 to 200 psi of argon, depending on the shim and channel design. The print length was 14 cm. In an example printing experiment, the printable lithium composition was printed 30 times from a single syringe with dispenser settings ranging from 80 psi to 200 psi. In this printing test experiment, the average flow conductance was

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[0050] Electrochemical Testing The effectiveness of prelithiating a printable lithium composition can be evaluated by printing the required amount of printable lithium onto the surface of a prefabricated electrode. The amount of prelithiated lithium is determined by testing the anode material in a half-cell format and calculating the lithium required to compensate for first-cycle losses due to SEI formation or other side reactions. To calculate the required amount of printable lithium, the lithium metal capacity of the composition must be known, which is approximately 3600 mAh / g on a dry lithium basis for the example composition.

[0051] The effect of prelithiation is tested using a graphite-SiO / NCA pouch cell. The graphite-SiO anode sheet formulation is synthetic graphite (90.06%) + SiO (4.74%) + carbon black (1.4%) + SBR / CMC (3.8%). The electrode capacity loading is 3.59 mAh / cm with a first cycle columbic efficiency (CE) of 87%. 2 Printable lithium is 0.15 mg / cm on the graphite-SiO anode. 2 The electrodes are dried at 80°C for 100 minutes and then laminated with a roller gap of approximately 75% of the electrode thickness. 7cm x 7cm electrodes are die-cut from the printable lithiated anode sheet. The cathode formulation is NCA (96%) + carbon black (2%) + PVdF (2%). The cathode is 6.8cm x 6.8cm and has a loading capacity of 3.37mAh / cm. 2The NCA cathode has a first cycle CE of 90%. The anode to cathode capacity ratio is 1.06, and the baseline first cycle CE for the entire cell is 77%. Single-layer pouch cells are assembled, and 1M LiPF6 / EC+DEC (1:1) is used as the electrolyte. The cells are preconditioned at 21°C for 12 hours, and then a formation cycle is performed at 40°C. The formation protocol is 0.1C charge to 4.2V, constant voltage to 0.01C, and 0.1C discharge to 2.8V. The described tests demonstrate a first cycle CE of 89%.

[0052] While the present approach has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those skilled in the art that other embodiments and examples may perform a similar function and / or achieve similar results, and all such equivalent embodiments and examples are within the spirit and scope of the present approach.

Claims

1. 1. A solid-state battery comprising a cathode, an anode, and a solid electrolyte, The anode is an active anode material; a printable lithium composition comprising lithium metal powder, a polymeric binder compatible with the lithium metal powder, a rheology modifier compatible with the lithium metal powder, and a solvent compatible with the lithium metal powder and the polymeric binder, on the active anode material on a current collector; A solid-state battery comprising: the printable lithium composition is solution-based; a) 5 to 25 wt. % of said lithium metal powder; b) 0.1 to 20% by weight of said polymer binder; c) 0.1 to 30 wt. % of said rheology modifier; d) 50 to 85% by weight of said solvent; The sum of components a) to d) is 100% by weight, The solvent is a non-polar solvent selected from the group consisting of acyclic hydrocarbons, cyclic hydrocarbons, and aromatic hydrocarbons. The solid-state battery.

2. 10. The solid-state battery of claim 1, wherein the active anode material is graphite, graphite-SiO, graphite-SnO, SiO, a tin / cobalt alloy, a tin / cobalt / carbon alloy, a silicon carbon alloy, a silicon / tin-based composite compound, a germanium-based composite, a titanium-based composite, elemental silicon, or germanium.

3. 3. The solid-state battery of claim 1 or 2, wherein the active anode material is coated with the printable lithium composition.

4. 4. The solid-state battery according to claim 1, wherein the lithium metal powder is a stabilized lithium metal powder.

5. 5. The solid-state battery of claim 1, wherein the rheology modifier is selected from the group consisting of carbonaceous materials, silicon-containing materials, tin-containing materials, Group IIA oxides, Group IIIA oxides, Group IVB oxides, Group VB oxides, and Group VIA oxides.

6. 6. The solid-state battery of claim 5, wherein the carbonaceous material is selected from the group consisting of carbon black, carbon nanotubes, graphite, hard carbon, and graphene.

7. 2. The solid-state battery of claim 1, wherein the polymer binder has a molecular weight of 1,000 to 8,000,000 and is selected from the group consisting of unsaturated elastomers, saturated elastomers, thermoplastics, polyacrylic acid, polyvinylidene chloride, and polyvinyl acetate.

8. 8. The solid-state battery of claim 7, wherein the unsaturated elastomer is selected from the group consisting of butadiene rubber, isobutylene, and styrene butadiene rubber.

9. 8. The solid state battery of claim 7, wherein the saturated elastomer is selected from the group consisting of ethylene propylene diene monomer rubber and ethylene vinyl acetate.

10. 8. The solid state battery of claim 7, wherein the thermoplastic material is selected from the group consisting of polystyrene, polyethylene, and polymers of ethylene oxide.

11. 11. The solid-state battery of claim 10, wherein the polymer of ethylene oxide is selected from the group consisting of poly(ethylene glycol) and poly(ethylene oxide).

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