Composite films and methods of making and using thereof

Abstract

Disclosed herein are composite films as well as methods of making and using thereof.

Description

[0001] Attorney Docket No. 10034-409 WO 1

[0002] GT Ref.: 2025-051 Composite Films and Methods of Making and Using Thereof

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims benefit of priority of U.S. Provisional Application No. 63 / 729,940, filed December 9, 2024, which is hereby incorporated herein by reference in its entirety.

[0004] BACKGROUND

[0005] Lithium-ion batteries are widely used in consumer electronics, electric vehicles, industrial energy-storage systems, and other applications due to their high energy density, long cycle life, and favorable performance characteristics. A typical lithium-ion cell includes a negative electrode, a positive electrode, a separator, and an electrolyte that enables the reversible intercalation and de-intercalation of lithium ions during charge and discharge. Although lithium-ion technology has become well established, continued improvements in safety, energy density, power capability, lifespan, and manufacturing efficiency remain important. Conventional electrode materials, separators, electrolytes, and other cell components can suffer from limitations such as thermal instability, limited cycling durability, insufficient ionic conductivity, or mechanical degradation under demanding operating conditions. As the performance requirements for lithium-ion batteries increase, there is a need for improved components and materials that address these shortcomings and enable higher-performance, more reliable, and safer battery systems.

[0006] SUMMARY

[0007] To address the challenges of increasing energy and power densities in rechargeable batteries, films comprising silver nanoparticles ( AgNPs) and carbon particles on a current collector were developed through a scalable and rapid photochemical / photothermal method. The composite films can be used as lithium (Li) host materials for Li metal batteries (LMBs), including liquid electrolyte based LMBs and all-solid-state LMBs (ASSLMBs), and even anode-free LMBs. By utilizing an ultraviolet (UV) laser system based photochemical process, this innovative approach directly fabricates AgNPs-carbon (AgC) Attorney Docket No. 10034-409 WO 1

[0008] GT Ref.: 2025-051

[0009] composite films on the current collector, addressing issues such as low Coulombic efficiency (CE) and dendritic Li growth. Furthermore, this technique facilitates the precise control over the size of AgNPs and graphiticity of carbon. When the carbon is highly graphitized, it promotes the formation of a carbon encapsulation around AgNPs, significantly enhancing the stability of the structures throughout cyclic Li plating and stripping processes. Moreover, this engineered processing technique has potential for the direct fabrication of various metal NPs or multi-metal alloys with controlled structures of carbon structures on the current collectors. This flexibility in material choice and structural control further enhances the performance and stability of LMBs, making this method a promising solution for advancing rechargeable battery technology.

[0010] DESCRIPTION OF DRAWINGS

[0011] Figure 1. A direct and scalable UV-laser-based manufacturing process for AgC Li host or interlayer structures. The schematic drawing illustrates a mass-producible Li anode host processing technology. The inset photo shows that the area of the slurry, both before and after exposure to laser irradiation, turns into a deep black color.

[0012] Figure 2. A direct and scalable UV-laser-based manufacturing process for AgC Li host or interlayer structures on a stainless current collector. The photographs illustrate the transformation of a) the slurry on the stainless steel foil current collector and b) the backside upon exposure to laser irradiation. The laser energy was adjusted across the foil as follows: 1) 3 μJ, 2) 2 μJ, 3) 1 μJ, and 4) 0.5 μJ. These adjustments correspond to the numbers showcased in images a) and b). c) A photograph of an extensive area of the slurry on the stainless steel foil current collector that has been subjected to laser treatment.

[0013] Figure 3. AgNPs size control by lasing speed. TEM Analysis of AgC Composite Morphology. Each composite was created using a consistent laser energy setting of 6 μJ and a spot diameter of 35 μm, with varied laser speeds of 100 mm / s (left), 500 mm / s (middle), and 1000 mm / s (right), respectively.

[0014] Figure 4. Carbon and AgNPs Morphological Structure Control by Lasing Energy. SEM (first row) and TEM (second row) analyses of AgC Composite Morphology. The laser irradiation parameters were consistently applied across all samples, featuring a speed of 100 mm / s and a spot diameter of 35 pm, with varied laser energy at 0.25 μJ (left), 0.5 μJ (middle), and 1 μJ (right). Attorney Docket No. 10034-409 WO 1

[0015] GT Ref.: 2025-051

[0016] Figure 5. Carbon and AgNPs Morphological Structure Control by Lasing Energy. SEM and EDX analysis of AgC composite morphology. The laser irradiation parameters were consistently applied across all samples, featuring a speed of 100 mm / s and a spot diameter of 35 μm, with varied laser energy at 0.25 μJ (left), 0.5 μJ (middle), and 1 μJ (right).

[0017] Figure 6. Carbon Structural Control by Lasing Energy. Raman spectroscopy analysis of AgC composites under various laser irradiation conditions of a fixed speed of 100 mm / s and a spot diameter of 35 pm with varied laser energy of 0.25 μJ, 0.5 μJ, and 1 μJ.

[0018] Figure 7. Carbon Encapsulated AgNPs. HR-TEM Characterization of AgC Composites.

[0019] Figure 8. AgNPs compositional control by precursor slurry design. TEM analysis of AgC composite across varying Ag content. The Ag precursor concentration in the slurry, was adjusted to 0.5, 5, 15, and 25 wt.%.

[0020] Figures 9A-9D. Electrochemical performance of half cells and full cells with AgC composite fabricated from different Ag precursor concentration in the slurry, adjusted to 0.5, 5, 15, and 25 wt.%. C. E. versus cycle number of Li||AgC composites cell under different conditions: (9A) 1 mA / cm2and 1 mAh / cm2(9B) 5 mA / cm2and 1 mAh / cm2(9C) 5 mA / cm2and 3 mAh / cm2. (9D) Cycling stability of LiFePO4 (LFP)||Li-plated AgC Composites.

[0021] Figure 10. Electrochemical performance of half cells with commercialized alternatives to assess the impact of carbon encapsulation on the electrochemical performance and stability of AgNPs within the composites. C. E. versus cycle number of LillAgC composites cell under 5 mA / cm2and 1 mAh / cm2.

[0022] Figure 11. Comparative SEM analyses of Laser-induced AgC and Conventional AgC composite morphology before and after half cell test.

[0023] DETAILED DESCRIPTION

[0024] The present invention can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present articles, systems, and / or methods are disclosed and described, it is to be understood that this invention is not limited to the specific or Attorney Docket No. 10034-409 WO 1

[0025] GT Ref.: 2025-051

[0026] exemplary aspects of articles, systems, and / or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0027] The following description of the invention is provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those of ordinary skill in the pertinent art will recognize that many modifications and adaptations to the present invention are possible and may even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is again provided as illustrative of the principles of the present invention and not in limitation thereof.

[0028] Definitions

[0029] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate aspects, can also be provided in combination in a single aspect. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single aspect, can also be provided separately or in any suitable subcombination.

[0030] As used in the description and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0031] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0032] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. As used in the specification and in the claims, the term “comprising” can include the aspects “consisting of’ and “consisting essentially of.” Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In this specification and in the claims, which follow, reference will be made to a number of terms that shall be defined herein. Attorney Docket No. 10034-409 WO 1

[0033] GT Ref.: 2025-051

[0034] For the terms "for example" and "such as," and grammatical equivalences thereof, the phrase "and without limitation" is understood to follow unless explicitly stated otherwise.

[0035] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used. Further, ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value.

[0036] Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint. Unless stated otherwise, the term “about” means within 5% (e.g., within 2% or 1%) of the particular value modified by the term “about.”

[0037] Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, 6 and any whole and partial increments therebetween. This applies regardless of the breadth of the range.

[0038] It will be understood that, although the terms "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or a section. Thus, a first element, Attorney Docket No. 10034-409 WO 1

[0039] GT Ref.: 2025-051

[0040] component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

[0041] As used lierein, the term "substantially" means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance generally, typically, or approximately occurs.

[0042] As used herein, the term “substantially,” in, for example, the context “substantially identical” or “substantially similar” refers to a method or a system, or a component that is at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or about 100% by similar to the method, system, or the component it is compared to.

[0043] “Nanoparticle”, as used herein, refers to any entity having a diameter of less than 1 micron (pm). Typically, particles have a greatest dimension (e.g., diameter) of 1000 nm or less. In some embodiments, particles have a diameter of 300 nm or less. In some embodiments, nanoparticles have a diameter of 200 nm or less. In some embodiments, nanoparticles have a diameter of 100 nm or less.

[0044] “Mean particle size,” as used herein, generally refers to the statistical mean particle size (diameter) of the particles in a population of particles. The diameter of an essentially spherical particle may be referred to as the physical or hydrodynamic diameter. The diameter of a non-spherical particle may refer preferentially to the hydrodynamic diameter. As used herein, the diameter of a non-spherical particle may refer to the largest linear distance between two points on the surface of the particle. Mean particle size can be measured using methods known in the art, such as dynamic light scattering or electron microscopy.

[0045] “Monodisperse” and “homogeneous size distribution,” are used interchangeably herein and describe a plurality of liposomal nanoparticles or microparticles where the particles have the same or nearly the same diameter or aerodynamic diameter. As used herein, a monodisperse distribution refers to particle distributions in which 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 86, 88, 89, 90, 91, 92, 93, 94, 95% or greater of the distribution lies within 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or 10% of the mass median diameter or aerodynamic diameter. Attorney Docket No. 10034-409 WO 1

[0046] GT Ref.: 2025-051

[0047] While aspects of the present invention can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only, and one of ordinary skill in the art will understand that each aspect of the present invention can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0048] The present invention may be understood more readily by reference to the following detailed description of various aspects of the invention and the examples included therein and to the Figures and their previous and following description.

[0049] Provided herein methods of fabricating a composite film comprising a population of metal particles dispersed within a carbonaceous matrix. These methods can comprise; preparing a mixture comprising a metal particle precursor and a carbon material dissolved or dispersed in a solvent; depositing a film of the mixture on a substrate; and irradiating the film with light under conditions effective to reduce the metal particle precursor, thereby forming the population of metal particles dispersed within the carbonaceous matrix.

[0050] In some embodiments, the metal particles comprise lithiophilic metal particles. Lithiophilic metal particles include metallic particles that exhibit favorable wetting, nucleation, or interfacial affinity for lithium, such that the particles promote uniform lithium deposition, improved lithium transport, or stable lithium-metal interfaces within a battery component. Lithiophilic behavior may arise from the intrinsic surface energy of the metal, the formation of lithium-rich alloys, or the ability of the metal surface to chemically or electrochemically interact with lithium under operating conditions. Examples of lithiophilic metal particles include, for example, nanoparticles comprising aluminum, gold, silver, magnesium, zinc, tin, indium, gallium, antimony, bismuth, cobalt, manganese, zinc, copper, and alloys or mixtures thereof, as well as metals capable of forming lithium alloys such as silicon, germanium, and lead. Compositions comprising lithiophilic metal particles may be particularly suitable for use in lithium ion batteries. Attorney Docket No. 10034-409 WO 1

[0051] GT Ref.: 2025-051

[0052] In some embodiments, the metal particles comprise silver particles, cobalt particles, manganese oxide particles, tin particles, zinc particles, copper particles, copper oxide particles, zinc oxide particles, tin oxide particles, or silicon dioxide particles. In some embodiments, the metal particles comprise silver particles, cobalt particles, tin particles, zinc particles, copper particles, particles comprising a lithiophilic alloy, or a combination thereof. In certain embodiments, the metal particles comprise silver particles.

[0053] In some embodiments, the metal particles comprise sodiophilic metal particles. Sodiophilic metal particles include metal particles that exhibit a favorable thermodynamic or kinetic interaction with metallic sodium, sodium ions, or sodium-containing species. In the context of sodium-based electrochemical cells, such particles promote wetting, nucleation, and uniform deposition of sodium on or within an electrode structure.

[0054] Sodiophilic metal particles may lower the nucleation overpotential for sodium plating, improve interfacial stability, enhance current distribution, or facilitate formation of a stable solid-electrolyte interphase. Examples of sodiophilic metal particles include metals that readily alloy with sodium or otherwise demonstrate strong interfacial affinity for sodium. Non-limiting examples of sodiophilic metal particles include tin (Sn), antimony (Sb), bismuth (Bi), aluminum (Al), indium (In), lead (Pb), and magnesium (Mg), as well as alloys or intermetallics thereof. Compositions comprising sodiophilic metal particles may be particularly suitable for use in sodium ion batteries.

[0055] In some embodiments, the metal particles comprise zincopliilic metal particles. Zincophilic metal particles include metal particles that exhibit a favorable interfacial interaction with metallic zinc or zinc ions, such that they promote nucleation, wetting, and uniform deposition of zinc in electrochemical cells. These particles may reduce the nucleation overpotential for zinc plating, improve current distribution, stabilize the zinc-electrolyte interface, and suppress dendritic growth in aqueous or non-aqueous zinc-based batteries. Zincopliilic behavior may arise from the ability of the metal to alloy with zinc, to form stable interfacial phases with zinc species, or to present a surface chemistry that promotes zinc adsorption and deposition. Non-limiting examples of zincophilic metal particles include silver (Ag), copper (Cu), gold (Au), nickel (Ni), indium (In), tin (Sn), bismuth (Bi), and their alloys or intermetallic compounds. Compositions comprising zincophilic metal particles may be particularly suitable for use in zinc ion batteries.

[0056] In some embodiments, the population of metal particles exhibits a monodisperse particle size distribution. Attorney Docket No. 10034-409 WO 1

[0057] GT Ref.: 2025-051

[0058] In some embodiments, the population of metal particles comprise nanoparticles. In some embodiments, the population of metal nanoparticles exhibit an average particle size, as measured by scanning electron microscopy (SEM), of at least 1 nm (e.g., at least 5 nm, at least 10 nm, at least 15 nm, at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm, at least 40 nm, at least 45 nm, at least 50 nm, at least 55 nm, at least 60 nm, at least 65 nm, at least 70 nm, at least 75 nm, at least 80 nm, at least 85 nm, at least 90 nm, at least 95 nm, at least 100 nm, at least 150 nm, at least 200 nm, at least 250 nm, at least 300 nm, at least 350 nm, at least 400 nm, at least 450 nm, at least 500 nm, at least 550 nm, at least 600 nm, at least 650 nm, at least 700 nm, at least 750 nm, at least 800 nm, at least 850 nm, at least 900 nm, or at least 950 nm). In some embodiments, the population of metal nanoparticles exhibit an average particle size, as measured by scanning electron microscopy (SEM), of less than 1 micron (e.g., 950 nm or less, 900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, 400 nm or less, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, 95 nm or less, 90 nm or less, 85 nm or less, 80 nm or less, 75 nm or less, 70 nm or less, 65 nm or less, 60 nm or less, 55 nm or less, 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, or at least 5 nm).

[0059] The population of metal nanoparticles exhibit an average particle size ranging from any of the minimum values described above to any of the maximum values described above. For example, population of metal nanoparticles can exhibit an average particle size, as measured by SEM, of from 1 nm to less than 1 micron (e.g., from 1 nm to 500 nm, from 1 nm to 250 nm, from 1 nm to 150 nm, from 1 nm to 100 nm, or from 1 nm to 80 nm, from 5 nm to less than 1 micron, from 5 nm to 500 nm, from 5 nm to 250 nm, from 5 nm to 150 nm, from 5 nm to 100 nm, or from 5 nm to 80 nm, from 25 nm to 500 nm, from 25 nm to 250 nm, from 25 nm to 150 nm, from 25 nm to 100 nm, or from 25 nm to 80 nm, from 50 nm to 500 nm, from 50 nm to 250 nm, from 50 nm to 150 nm, from 50 nm to 100 nm, or from 50 nm to 80 nm).

[0060] In some embodiments, the metal particle precursor comprises a metal coordination complex. By way of example, in some embodiments when the metal particles comprise silver particles, the metal particle precursor comprises Ag(acac)2.

[0061] The carbon material can comprise any suitable material or combination of carbonaceous materials. By way of example, in some embodiments, the carbon material can Attorney Docket No. 10034-409 WO 1

[0062] GT Ref.: 2025-051

[0063] comprise graphite, carbon fibers, carbon black (e.g., amorphous carbon black), mesoporous carbon, microporous carbon, carbon nanotubes (including single-walled and multi-walled nanotubes), carbon nanofibers, carbon nanospheres, carbon onions, graphene and graphene-derived materials (such as reduced graphene oxide), hard carbon, soft carbon, carbon aerogels, carbon xerogels, pitch-derived carbon, and coke-derived carbon. In certain embodiments, the carbon material comprises graphite, carbon fibers, amorphous carbon black, or a combination thereof.

[0064] In some embodiments, the mixture further comprises a binder. In some embodiments, the binder comprises polyethylene, polypropylene, polytetrafluoroethylene (PTFE), Polyvinylidene fluoride (PVDF), styrene butadiene rubber, a tetrafluoroethylene hexafluoro ethylenic copolymer, a tetrafluoroethylene hexafluoropropylene copolymer (FEP), a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene resin (PCTFE), a propylene- tetrafluoroethylene copolymer, an ethylene-chlorotrifluoroethylene copolymer (ECTFE), an ethylene-acrylic acid copolymer, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyvinyl alcohol (PVA), a copolymer thereof, or a blend thereof. In some embodiments, the binder comprises a water soluble polymer such as styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyvinyl alcohol (PVA), a copolymer thereof, or a blend thereof. In certain embodiments, the binder comprises polyvinylidene fluoride (PVDF).

[0065] In some embodiments, the mixture comprises a slurry.

[0066] In some embodiments, the solvent comprises N-methyl-2-pyrrolidone.

[0067] In some embodiments, the substrate comprises a current collector, such as a copper current collector or a stainless steel current collector.

[0068] In some embodiments, the method further comprises drying the film prior to irradiating the film with light. This can comprise allowing the solvent to evaporate, heating the film, flowing a gas (e.g., air) over the film, applying a vacuum over the film, or a combination thereof.

[0069] Irradiating the film with light can comprise directing light of varying wavelengths on the film. In some examples, the light can have a wavelength in the infrared (IR), visible, and / or ultraviolet (UV) regions of the electromagnetic spectrum.

[0070] In some embodiments, irradiating the film with light comprises impinging a laser beam on the film. In some embodiments, the light comprises light having a wavelength in Attorney Docket No. 10034-409 WO 1

[0071] GT Ref.: 2025-051

[0072] the infrared (IR), visible, and / or ultraviolet (UV) regions of the electromagnetic spectrum. In certain embodiments, the light comprises light having a wavelength in the UV region of the electromagnetic spectrum.

[0073] In some embodiments, irradiating the film with light comprises directing a UV laser beam on a surface of the film. In some embodiments, the method further comprises altering the laser energy, laser fluence, laser speed, or a combination thereof to control the size of the metal particles, the nature of the carbonaceous matrix, or a combination thereof.

[0074] In some embodiments, the carbonaceous matrix comprises graphite. In some embodiments, the graphite at least partially encapsulates the metal particles.

[0075] Also provided herein are composite films prepared by the methods described herein. In some embodiments, the composite films can have a thickness of from 2.5 microns to 25 microns, such as about 10 microns. In some embodiments, these composites films can be used as current collectors for use in fabricating an electrodes.

[0076] Accordingly, also provided herein are electrodes (e.g., anodes) comprising these current collectors. In some embodiments, the electrode can further comprise Li metal plated on the current collector. In some embodiments, the current collector enhances the uniformity and / or density of the lithium plating.

[0077] Also provided herein are electrochemical cells (e.g., lithium metal batteries, all-solid-state battery (ASSB), all-solid-state LMBs (ASSLMBs), lithium ion batteries, sodium ion batteries, zinc ion batteries, etc.)) comprising an electrode described herein. In some embodiments, the current collector (and by extension the electrode) enhances the cyclic stability of the electrochemical cell.

[0078] In certain examples, the electrochemical cell comprises a Li-based electrochemical cell (e.g., a lithium metal battery or lithium ion battery), and the metal particles present in the composite film comprises lithiophilic metal particles. In certain examples, the electrochemical cell comprises a Na-based electrochemical cell (e.g., a sodium ion battery), and the metal particles present in the composite film comprises sodiophilic metal particles. In certain examples, the electrochemical cell comprises a Zn-based electrochemical cell (e.g., a zinc ion battery), and the metal particles present in the composite film comprises zincophilic metal particles.

[0079] Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified. Attorney Docket No. 10034-409 WO 1

[0080] GT Ref.: 2025-051

[0081] EXAMPLES

[0082] The invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of non-critical parameters which can be changed or modified to yield essentially the same results.

[0083] Example 1. Scalable Laser Processing of Direct Fabrication of Silver Nanoparticles (AgNPs)-Carbon (AgC) Composites Films on Current Collectors for Lithium Metal Batteries (LMBs)

[0084] Summary

[0085] To enhance the efficiency and reduce production costs of LMBs — in the case of liquid electrolyte-based LMBs, ASSLMBs, and anode-free LMBs ---described herein are scalable and rapid photochemical / photothermal techniques that can be used to create composite Li host films directly on a current collector. While AgC composites have shown significant progress in ensuring even Li metal deposition, thereby extending cycle life and enhancing energy density, their production is often limited by high energy consumption and lengthy processing times.

[0086] Our method seeks to address these challenges by employing a fast, scalable UV-laser-based photochemical process to produce composite films that facilitate direct Li metal deposition onto the current collector. Traditional methods for creating AgC composites involve chemically or thermally reducing AgNPs, followed by a purification process, mixing with carbon to form a slurry, and then applying this mixture to the current collector. In contrast, our approach involves mixing an Ag precursor with carbon materials to create a slurry that is directly applied to the current collector. Subsequent UV light exposure induces the reduction of Ag, forming nanoparticles and synthesizing the composite material with carbon. This technique allows for the adjustment of AgNPs content based on the slurry composition and the modification of the AgNPs' size and the carbon's graphiticity through the UV exposure conditions. Additionally, the graphitized carbon can encapsulate AgNPs, enhancing cyclic stability and potentially improving adhesion with solid electrolytes when applied to ASSLMBs, due to its high surface area.

[0087] In tackling the complex challenges associated with the material and processing engineering of AgC -based composites, further to replace AgNPs with other metal or metal Attorney Docket No. 10034-409 WO 1

[0088] GT Ref.: 2025-051

[0089] alloy NPs, we aim to develop a technology that streamlines the creation of sophisticated composites. This includes embedding AgNPs within a range of carbon matrices, from amorphous to graphitic structures. Our approach not only demonstrates the successful integration of carbon encapsulated AgNPs within the composites but also ensures the stability of these structures during cyclic Li plating and stripping processes. To achieve our goals, we have outlined the following four strategic objectives:

[0090] 1. Direct Synthesis of AgC Composites onto Current Collectors.

[0091] 2. Morphological and Material Properties Analysis: Investigations to understand how variations in the processing conditions affect the morphological and material properties of AgC.

[0092] 3. Control of Ag Content and Its Correlation with Electrochemical Performance:

[0093] Experiment with slurry composition to adjust the amount of Ag content within the composites, aiming for optimal performance.

[0094] 4. Investigation of the Effects of Carbon Encapsulation of AgNPs within the composites: Conduct comparative experiments with commercialized alternatives to assess the impact of carbon encapsulation on the electrochemical performance and stability of AgNPs within the composites.

[0095] The successful implementation of this processing technique has the potential to revolutionize the manufacturing landscape for anode hosts and interlayers. By potentially reducing energy requirements and production time, this technique not only aims to streamline the manufacturing process but also to enhance the performance and safety of LMBs. Specifically, it seeks to promote more uniform Li deposition — a critical factor in improving battery performance. Through this innovative approach, we are poised to advance Li battery technology, pushing it towards greater viability and sustainability for widespread application.

[0096] Introduction

[0097] Li metal stands out as the ideal anode material for high-energy-density ASSBs in EVs, offering advantages over the conventional graphite anode with its higher theoretical capacity and lower electrochemical potential. Nonetheless, issues like low C. E. and volumetric expansion due to Li dendrite growth present significant safety and cycle life challenges. To address these concerns, an innovative structure of an interlayer on the current collector featuring lithiophilic nanoparticles and a carbon composite has been devised. This approach Attorney Docket No. 10034-409 WO 1

[0098] GT Ref.: 2025-051

[0099] minimizes the use of excess Li, potentially boosting the energy density of LMBs significantly and reducing costs by lessening the reliance on Li.

[0100] In particular, the AgC nanocomposite layer serving as the anode host is instrumental due to Ag's affinity with Li and its capacity to lower the nucleation energy for Li formation, thereby enabling uniform Li deposition on the current collector and enhancing the LMB's performance. Carbon is traditionally used as a protective layer or host for Li metal deposition and acts as a barrier to safeguard against reactions with solid electrolytes or to preserve AgNPs structures during cyclic Li deposition. Samsung's recent findings highlight that the AgC nanocomposite layer, placed between the solid electrolyte and current collector, allows ASSBs to attain prolonged cycle life and elevated energy density without the use of Li metal. Although AgC-based ASSBs have advanced in performance and safety, achieving commercial viability is contingent upon cost-effectiveness.

[0101] Given the challenges in the material and processing engineering of the AgC nanocomposite, a technology that allows for easy adjustment of the size and quantity of AgNPs, as well as the quality of carbon, with a fast and scalable manufacturing process, is needed. We aim to develop a technology utilizing laser processing that can effortlessly modify the materials and support mass production. Through this facile method, our final goal is to find the optimal material that can stably accommodate and release Li by controlling the quality of AgNPs and carbon.

[0102] Technical Approach

[0103] Described herein is a mass-producible Li anode host processing technology that allows for easy adjustment of the size and quantity of AgNPs, as well as the quality of carbon, with a fast and scalable UV-laser based manufacturing process. A goal is to ensure that AgNPs and carbon coexist in the most efficient way possible, serving as a stable and effective Li host.

[0104] Direct Synthesis of AgC Composites onto Current Collectors As Figure 1 shows, a slurry containing carbon black, PVDF (polyvinylidene fluoride), Ag(acac)₂ (silver acetylacetonate), and NMP (N-Methyl-2-pyrrolidone) is cast onto a copper or stainless steel foil current collector. Following this, the slurry-coated substrate is exposed to laser irradiation, resulting in the formation of an AgC composite; the area of the slurry exposed to laser irradiation turns into a deep black color.

[0105] The slurry on the stainless steel foil current collector was exposed to laser irradiation, where the treated areas manifest a transition to a deep black color (Figure 2). Attorney Docket No. 10034-409 WO 1

[0106] GT Ref.: 2025-051

[0107] The parameters for the laser irradiation process were uniformly set, with a speed of 100 mm / s, repetition rate of 250,000 Hz, and a spot diameter of 35 μm, while the laser energy was adjusted across different samples: 1) 3μJ, 2) 2 μJ, 3) 1 μJ, and 4) 0.5 μJ. These adjustments correspond to the variations showcased in Figure 2, panels a and b. When the lasing energy was above 2 pj, the stainless foil was damaged to from wrinkles, while there was no damage on the copper foil. Therefore, the laser energy below 2μJ, when further laser processing was carried out for slurry coated on the stainless steel. Figure 2, panel c depicts the extensive area of the slurry on the stainless steel foil current collector that has been subjected to laser treatment, highlighting the uniformity and scale of the process.

[0108] Morphological and Material Properties Analysis: Investigations to understand how variations in the processing conditions affect the morphological and material properties of AgC

[0109] The composition of the precursor slurry and the processing laser conditions were varied to investigate the morphological, compositional, and material properties of AgC. Figure 3 illustrates the morphological changes in AgC composites on copper current collectors analyzed through Transmission Electron Microscopy (TEM). Each composite was fabricated under uniform conditions: a laser energy setting of 6 μJ, a repetition rate of 250,000 Hz, and a spot diameter of 35 μm. However, the laser speed was varied to examine its impact on the structure of the composites, with speeds set at 100 mm / s, 500 mm / s, and 1000 mm / s, respectively. This progression demonstrates that a decrease in lasing speed increases the exposure duration on the AgC Composites, resulting in larger AgNPs with diameters of 80 nm at 100 mm / s, compared to 5–10 nm and 3–8 nm diameters at 500 mm / s and 1000 mm / s, respectively, highlighting distinct morphological differences due to fabrication speeds. However, the use of varying laser speeds led to inconsistencies in material uniformity, prompting subsequent experiments to fix the speed while adjusting laser energy.

[0110] Figure 4 presents a detailed examination of AgC Composites using both Scanning Electron Microscopy (SEM) (first row) and TEM (second row) imaging. The laser irradiation conditions remained constant across all samples, featuring a speed of 100 mm / s, a repetition rate of 250,000 Hz, and a spot diameter of 35 μm. The study varied the laser energy for each sample, set at 0.5 μJ (left), 1 μJ (middle), and 2 μJ (right), enabling a thorough comparison of how different energy levels affect the composites' microstructural and nanostructural characteristics. Increasing laser energy led to the graphitization of Attorney Docket No. 10034-409 WO 1

[0111] GT Ref.: 2025-051

[0112] carbon, forming graphene sheets. The formation of these graphene sheets, which enveloped the reducing AgNPs and prevented their agglomeration, facilitated the production of more uniform materials. Further SEM and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed that the creation of graphene layers effectively inhibited the clustering of small AgNPs (Figure 5).

[0113] Raman spectroscopy analysis, conducted with laser energies of 0.25 μJ, 0.5 μJ, and 1 μJ, revealed that the graphitic structures became more pronounced with increasing laser energy, as indicated by the sharper 2D peaks (Figure 6). This observation confirms the additional formation of graphitic structures. High-resolution TEM (HR-TEM) Characterization of AgC composites, especially those fabricated with a laser energy of 1 μJ, showed that graphitic carbon formed a shell structure around the Ag, clearly preventing the agglomeration of AgNPs (Figure 7). This structure provides further evidence of the effectiveness of the selected laser parameters in enhancing the uniformity and stability of the AgC composites.

[0114] Control of Ag Content and Its Correlation with Electrochemical Performance: Experiment with slurry composition to adjust the amount of Ag content within the composites, aiming for optimal performance. The subsequent analysis explored the influence of varying Ag precursor concentrations within the slurry on the morphology and electrochemical performance of AgC composites. The study focused on the impact of Ag concentration under controlled fabrication conditions, despite maintaining uniform laser parameters — energy at 2 μJ, spot diameter of 35 μm, and a constant speed of 100 mm / s. The variable of interest was the Ag precursor concentration in the slurry, adjusted to 0.5, 5, 15, and 25 wt.%. This systematic variation in Ag content provided a detailed comparison of how increasing amounts of Ag affect the structural characteristics of the composites. TEM imaging revealed the morphological evolution of the composites as a function of Ag content (Figure 8). Initially, up to a concentration of 15 wt.%, AgNPs with diameters less than 10 nm were well-dispersed, forming structured composites. However, at 25 wt.%, AgNPs larger than 10 nm were observed to agglomerate.

[0115] To investigate the electrochemical performance of half and full cells incorporating AgC composites with varied Ag precursor concentrations, experiments were conducted. A comparative analysis of the electrochemical behavior of half and full cells using AgC composites synthesized with Ag precursor concentrations of 0.5, 5, 15, and 25 wt.% showed Attorney Docket No. 10034-409 WO 1

[0116] GT Ref.: 2025-051

[0117] that at a current density of 1 mA / cm² and an areal capacity of 1 mAh / cm² in half-cell tests, there was no significant performance difference (Figure 9A). However, at 5 mA / cm2and 1 mAh / cm2or 5 mA / cm2and 3 mAh / cm2, cells with 15% Ag precursor concentration exhibited notably superior stability and performance (Figure 9B, 9C). This improvement is attributed to the optimal amount of lithiophilic Ag, which prevents AgNP agglomeration, thereby maximizing the accessible surface area for Li intake. Additionally, full cells were fabricated using anodes with 2 mAh / cm2Li plating and a LiFePO₄ (LFP) cathode with a capacity of 2.34 mAh / cm2to evaluate performance (Figure 9D). Similar to the half-cell tests, cells with 15 wt.% Ag precursor concentration demonstrated the highest capacity and cyclic stability. This finding indicates that the AgC composition at this concentration provides a stable structure for capturing and efficiently transferring Li to the cathode.

[0118] Investigation of the Effects of Carbon Encapsulation of AgNPs within the composites: Conduct comparative experiments with commercialized alternatives to assess the impact of carbon encapsulation on the electrochemical performance and stability of AgNPs within the composites

[0119] To explore the impact of graphitic carbon forming a shell structure around the AgNPs on the cyclic Li plating and stripping process, half-cell tests were conducted comparing commercial AgNPs and carbon composites with laser-induced AgC featuring carbon encapsulation of AgNPs. Both the laser-induced AgC and the commercial AgC composites had a final Ag content fixed at approximately 15 wt.%, with the commercial AgNPs being 10 nm in size. The laser-induced AgC demonstrated notably superior stability and performance in the half-cell tests (Figure 10). This enhancement in the laser-induced AgC can be attributed to the smaller size of AgNPs, which reduces the overpotential for Li plating-stripping nucleation and increases the specific surface area of lithiophilic sites. Furthermore, SEM analysis of the morphology of both laser-induced AgC and conventional AgC composites before and after 100 cycles of the half-cell test reveals that the carbon encapsulation effectively prevents AgNPs from agglomerating and moving within the composites (Figure 11). This contributes to enhanced electrochemical performance by maintaining the structural integrity and functional efficacy of the composites throughout the cycling process.

[0120] Impacts Attorney Docket No. 10034-409 WO 1

[0121] GT Ref.: 2025-051

[0122] Utilizing laser technology alongside the traditional slurry casting method to quickly and easily fabricate Li hosts or interlayer on current collectors presents an attractive approach that offers the potential to diversely manufacture composite material properties, suggesting possibilities for cost reduction in Li batteries. This technique especially showcases the ability to vary the quantity and size of AgNPs in AgC nanocomposites and to adjust the graphiticity of carbon. The technology facilitates the development of efficient Li hosts across liquid, polymer, and inorganic electrolytes. Consequently, it is anticipated that this method could significantly reduce or even eliminate the amount of Li in traditional LMB anodes, as well as processing costs. Furthermore, although we have only demonstrated composites of lithiophilic metal nanoparticles with Ag and bare carbon, we anticipate that this technology could be extended to engineer a broader variety of lithiophilic metal nanoparticles, such as tin, zinc, and iron, as well as lithiophilic alloy nanoparticles, in addition to further diversification in carbon engineering.

[0123] This innovative approach paves the way for further advancements in anode engineering to address the inherent challenges associated with LMBs. We expect this economical anode engineering strategy to play a crucial role in meeting global energy needs, from EVs to large-scale energy storage systems.

[0124] The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, which are intended as illustrations of a few aspects of the claims. Any compositions and methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Further, while only certain representative compounds, components, compositions, and method steps disclosed herein are specifically described, other combinations of the compounds, components, compositions, and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein or less, however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

[0125] The term “comprising” and variations thereof as used herein is used synonymously with the term “including” and variations thereof and are open, non-limiting terms. Although the terms “comprising” and “including” have been used herein to describe various Attorney Docket No. 10034-409 WO 1

[0126] GT Ref.: 2025-051

[0127] embodiments, the terms “consisting essentially of’ and “consisting of’ can be used in place of “comprising” and “including” to provide for more specific embodiments of the invention and are also disclosed. Other than where noted, all numbers expressing geometries, dimensions, and so forth used in the specification and claims are to be understood at the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, to be construed in light of the number of significant digits and ordinary rounding approaches.

[0128] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

Claims

Attorney Docket No. 10034-409WO1GT Ref.: 2025-051WHAT IS CLAIMED IS:

1. A method of fabricating a composite film comprising a population of metal particles dispersed within a carbonaceous matrix, the method comprising;preparing a mixture comprising a metal particle precursor and a carbon material dissolved or dispersed in a solvent;depositing a film of the mixture on a substrate; andirradiating the film with light under conditions effective to reduce the metal particle precursor, thereby forming the population of metal particles dispersed within the carbonaceous matrix.

2. The method of claim 1, wherein the metal particles comprise lithiophilic metal particles, sodiophilic metal particles, or zincophilic metal particles.

3. The method of any one of claims 1-2, wherein the metal particles comprise silver particles, cobalt particles, tin particles, zinc particles, copper particles, particles comprising a lithiophilic alloy, or a combination thereof.

4. The method of any one of claims 1-3, wherein the metal particles comprise silver particles5. The method of any one of claims 1-4, wherein the population of metal particles exhibits a monodisperse particle size distribution.

6. The method of any one of claims 1 -5, wherein the population of metal particles comprise nanoparticles.

7. The method of any one of claims 1-6, wherein the population of metal particles exhibits an average particle size of from 1 nm to 500 nm, as measured by electron microscopy.Attorney Docket No. 10034-409WO1GT Ref.: 2025-0518. The method of any one of claims 1-7, wherein the metal particle precursor comprises a metal coordination complex.

9. The method of any one of claims 1-8, wherein the metal particle precursor comprises Ag(acac)2.

10. The method of any one of claims 1-9, wherein the carbon material comprises graphite, carbon fibers, amorphous carbon black, or a combination thereof.

11. The method of any one of claims 1-10, wherein the mixture further comprises a binder.

12. The method of claim 11, wherein the binder comprises polyethylene, polypropylene, polytetrafluoroethylene (PTFE), Polyvinylidene fluoride (PVDF), styrene butadiene robber, a tetrafluoroethylene hexafluoro ethylenic copolymer, a tetrafluoroethylene hexafluoropropylene copolymer (FEP), a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene resin (PCTFE), a propylene- tetrafluoroethylene copolymer, an ethylene-chlorotrifluoroethylene copolymer (ECTFE), an ethylene-acrylic acid copolymer, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyvinyl alcohol (PVA), copolymers thereof, or blends thereof.

13. The method of claim 12, wherein the binder comprises polyvinylidene fluoride (PVDF).

14. The method of any one of claims 1-13, wherein the mixture comprises a slurry.

15. The method of any one of claims 1-14, wherein the solvent comprises N-methyl-2-pyrrolidone.

16. The method of any one of claims 1-15, wherein the substrate comprises a current collector, such as a copper current collector or a stainless steel current collector.Attorney Docket No. 10034-409WO1GT Ref.: 2025-05117. The method of any one of claims 1-16, wherein the method further comprises drying the film prior to irradiating the film with light.

18. The method of any one of claims 1-17, wherein irradiating the film with light comprises impinging a laser beam on the film.

19. The method of any one of claims 1-18, wherein the light comprises light having a wavelength in the infrared (IR) region of the electromagnetic spectrum, the visible region of the electromagnetic spectrum, the ultraviolet (UV) region of the electromagnetic spectrum, or a combination thereof.

20. The method of any one of claims 1-19, wherein irradiating the film with light comprises directing a UV laser beam on a surface of the film.

21. The method of claim 20, wherein the method further comprises altering the laser energy, laser fluence, laser speed, or a combination thereof to control the size of the metal particles, the nature of the carbonaceous matrix, or a combination thereof.

22. The method of any one of claims 1 -21, wherein the carbonaceous matrix comprises graphite.

23. The method of claim 22, wherein the graphite at least partially encapsulates the metal particles.

24. A composite film prepared by the method of any one of claims 1-23.

25. The composite film of claim 24, wherein the composite film has a thickness of from 2.5 microns to 25 microns, such as about 10 microns.Attorney Docket No. 10034-409WO1GT Ref.: 2025-05126. The composite film of claim 24 or 25, wherein the composite film Is disposed on a current collector, such as a copper current collector or a stainless steel current collector.

27. A current collector for use In fabricating an electrode comprising the composite defined by claim 26.

28. An electrode comprising the current collector of claim 27.

29. The electrode of claim 28, further comprising Li metal plated on the current collector.

30. An electrochemical cell comprising the electrode defined by claim 28 or claim 29.

31. The electrochemical cell of claim 30, wherein the electrochemical cell comprises a lithium metal battery, a lithium ion battery, a sodium ion battery, a sodium metal battery, a zinc ion battery, or a zinc metal battery.

32. The electrochemical cell of claim 30, wherein the electrochemical cell comprises an all- solid-state battery (ASSB), such as an all-solid-state LMBs (ASSLMBs).

33. The electrochemical cell of any one of claims 30-32, wherein the current collector enhances the cyclic stability of the electrochemical cell.

34. The electrode of claim 29, wherein the current collector enhances the uniformity and / or density of the lithium plating.

Images