Battery electrode current collectors

Abstract

The device may include a battery electrode comprising a substrate having one or more polymeric materials and a layer disposed on the substrate. The layer may include one or more conductive materials, have a thickness of 12 micrometers or less, and have a porosity of at least 5% by volume. Furthermore, the electrode layer, including the seed layer, may comprise a multiplicity of fused nanoparticles. The electrode layer may also comprise a lithium metal layer disposed on the multiplicity of fused nanoparticles. The electrode layer may be formed by producing a seed layer comprising nanoparticles on a polymeric current collector layer. The formulation for forming the seed layer may include nanoparticles having ligands, which may then be removed using one or more thermal treatments and / or one or more chemical treatment processes. The seed layer is electrically conductive and may function as a current collector when disposed on the polymeric substrate.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application claims priority to U.S. Provisional Application No. 63 / 377,319, filed September 27, 2022, and U.S. Provisional Application No. 63 / 505,896, filed June 2, 2023, the contents of both applications being incorporated herein by reference.

[0002] (Technical field) FIELD OF THE DISCLOSURE Embodiments of the present disclosure generally relate to electrode compositions and methods for making same in lithium-ion batteries. [Background technology]

[0003] Lithium-ion batteries (LIBs) can be used in a variety of applications, including portable electronics, electric vehicles, and electric aircraft. State-of-the-art LIBs have limited cell-level energy density due to the low specific energy of their lithium-containing active materials, namely, graphite anodes and metal oxide or metal phosphate cathodes. Improving the energy density of LIBs could lead to their widespread use and increased viability as an energy source.

[0004] One way to improve the energy density of LIBs is to replace the standard graphite anode with one composed of Li metal. Li metal has a specific capacity of approximately 3860 mAh / g, more than 10 times that of graphite. Furthermore, the potential at which Li metal deposits on the current collector from a typical Li battery electrolyte (0 V vs. Li / Li + , -3.04V vs. Standard Hydrogen Electrode (SHE)) is also improved compared to graphite. Graphite is typically 0.005 to 0.5V vs. Li / Li + The combination of these two properties gives Li metal anodes improved energy density compared to graphite anodes.

[0005] Furthermore, secondary lithium-ion battery electrodes require at least two components: (1) an active material that reversibly stores and releases lithium ions, and (2) a conductive current collector in intimate contact with the active material to facilitate the electron transport necessary for the active material to reversibly intercalate or alloy with lithium at an appropriate rate. For a material to function solely as a current collector and not as an active material, it must be electrically conductive within the voltage range of interest without alloying or intercalating with lithium. A limited number of materials meet this criterion, including copper, nickel, titanium, and iron on the anode side. Copper, in particular, is widely used as a negative electrode current collector in lithium-ion batteries due to its high conductivity, ductility, abundance, and minimal reaction with lithium.

[0006] The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate certain embodiments and, together with the description herein, serve to explain certain principles of the methods, systems, and devices disclosed herein. The description herein is better understood when read in conjunction with the accompanying drawings, which are set forth by way of example and not by way of limitation. The accompanying drawings are set forth by way of example, not by way of limitation, and should be understood to refer to the same elements throughout the drawings unless the context requires otherwise. It should also be understood that some or all of the drawings are schematic representations for illustrative purposes and do not necessarily represent the actual relative size or position of the elements depicted. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a flow diagram of an exemplary process for manufacturing a porous current collector layer for a lithium-ion battery, in accordance with one or more examples. [Figure 2] In accordance with one or more examples, a device is shown that includes an active material layer disposed on a porous current collector layer of a lithium ion battery composed of spherical conductive particles. [Figure 3] In accordance with one or more examples, a device is provided that includes active material particles contained in a layer that is also comprised of spherical conductive particles for a lithium ion battery. [Figure 4] 1 illustrates, in accordance with one or more examples, a device including an active material layer disposed on a porous current collector layer of a lithium ion battery composed of conductive nanowires. [Figure 5] In accordance with one or more examples, a device is shown that includes active material particles contained in a layer that is also composed of conductive nanowires. [Figure 6] In accordance with one or more examples, a device is provided that includes a porous current collector layer for a lithium ion battery composed of spherical conductive particles and an active material layer disposed on a porous polymer substrate. [Figure 7] FIG. 1 is a diagram of a process for producing a nanoparticle seed layer on the surface of a current collector layer. [Figure 8] FIG. 1 illustrates an example process for producing a lithium metal coated substrate. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following is a simplified summary of one or more embodiments of the present disclosure in order to provide a basic understanding of these embodiments. This summary is not an exhaustive overview of all contemplated embodiments, nor is it intended to identify key or critical elements of all embodiments or to delineate the scope of some or all embodiments.

[0009] The disclosed methods and compositions are described for lithium-ion battery electrodes. The methods and compositions disclosed herein enable lithium-ion batteries with significantly higher gravimetric energy densities than the state-of-the-art without compromising other key battery performance metrics. The disclosed methods are commercially and technically more amenable to mass-production lithium-ion battery (LIB) manufacturing than other methods for producing lithium-ion battery electrodes and metallized polymer current collectors. The disclosed compositions are commercially and technically more amenable to mass-production lithium-ion battery (LIB) manufacturing than other compositions for lithium-ion battery electrodes and metallized polymer current collectors. Furthermore, the present invention relates to a seed layer deposited on a current collector layer that increases the surface area available for lithium deposition while minimizing the thickness of the lithium-ion battery electrode. In some instances, the seed layer itself also functions as the current collector.

[0010] In one or more examples, the device includes a battery electrode including a substrate including one or more polymeric materials and a layer disposed on the polymeric substrate, the layer including one or more conductive materials, having a thickness of 12 micrometers or less, and having a porosity of at least 5% by volume.

[0011] In one or more additional examples, a method includes providing a substrate for a battery electrode, the substrate including one or more polymeric materials. The method also includes forming a layer on the substrate, the layer including one or more conductive materials, having a thickness of 12 micrometers or less, and having a porosity of at least 5% by volume.

[0012] In one or more further examples, the formulation includes one or more solvents, first particles comprised of one or more conductive materials, and second particles comprised of one or more electrode active materials.

[0013] In yet another example, a seed layer for a Li metal anode can be produced that includes nanoparticles. The seed layer can be formed on a current collector layer, and Li metal can be deposited on the seed layer. The seed layer can have some porosity. In various examples, the seed layer can be formed from nanoparticles that have ligands attached to them, and the ligands can then be removed using one or more thermal treatment processes and / or one or more chemical treatment processes. In at least some examples, the seed layer can comprise nanoparticles that are formed in situ during decomposition of a molecular precursor. The nanoparticles in the seed layer can exist as nanoparticle clusters composed of fused groups of nanoparticles. Lithium metal can be deposited on the seed layer to create an anode for a battery cell.

[0014] In various examples, a method of fabricating a substrate comprising a nanostructured seed layer on one or more surfaces of a current collector may include preparing an ink comprising a solution comprising at least ligand-functionalized nanoparticles and a solvent, applying a thin wet film of the ink to a current collector using a solution-phase thin film coating process, drying the thin wet film to produce a thin dry film of the ligand-functionalized nanoparticles, and performing one or more thermal and / or chemical treatments on the thin dry film, thereby fabricating a substrate comprising a free-standing porous nanostructured seed layer on one or more surfaces of the current collector.

[0015] In one or more examples, a method for fabricating a substrate with a nanostructured seed layer on one or more surfaces of a current collector can include preparing an ink comprising a solution comprising at least one or more molecular precursors and a solvent. Additionally, a solution-phase thin-film coating process can be used to apply a thin wet film of the ink to the current collector. The current collector can comprise a polymeric material such as polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate. In one or more additional examples, the current collector can comprise a polymeric material such as polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate in addition to a metal such as copper, titanium, nickel, or stainless steel. In one or more further examples, the current collector can be composed entirely of a polymeric material such as polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate. In at least some examples, the nanostructured seed layer deposited on the current collector can be electrically conductive and provide current-carrying capability. The thin wet film can be subjected to one or more thermal and / or chemical treatments to produce a substrate with a free-standing porous nanostructured seed layer on at least one surface of the current collector or polymer substrate. The molecular precursor can include an organometallic compound.

[0016] Additionally, the seed layer can be formed from a formulation including a solvent, a plurality of nanoparticles disposed in the solvent, the plurality of nanoparticles having one or more dimensions from about 0.5 nanometers to about 500 nanometers, and one or more ligands attached to individual nanoparticles of the plurality of nanoparticles. The one or more ligands can have a molecular weight of 20 Daltons (Da) to 10 kDa. The formulation can be characterized as an ink that is deposited onto a current collector layer of a battery cell.

[0017] Additionally, a method for making a lithium metal coated substrate can include providing a substrate with a nanoparticle seed layer on one or more surfaces of a current collector, and electrodepositing lithium onto the nanoparticle seed layer of the substrate to form the lithium metal coated substrate.

[0018] In one or more embodiments, a battery may include a housing and one or more battery cells disposed within the housing, each of the one or more battery cells including an electrode layer including (i) a seed layer composed of a multitude of fused nanoparticles and (ii) a lithium metal layer disposed on the multitude of fused nanoparticles, one or more separator layers, and one or more electrolyte layers including an electrolyte.

[0019] Attempts to widely adopt Li metal as an anode material have been hampered by several challenges. The primary challenge is that the morphology of the Li metal deposited on the anode current collector during battery charging is typically highly heterogeneous, consisting of tree-like structures ("dendrites") or other irregular shapes that tend to delaminate from the rest of the lithium metal anode during repeated battery cycling. This depleted lithium eventually becomes electrochemically inactive and no longer contributes to battery capacity. In some instances, the Li metal dendrites can grow sufficiently large to penetrate the polymer separator between the anode and cathode, causing an electrical short circuit with the cathode. In such cases, the Joule heat generated by the energy released by the electrical short circuit is often sufficient to cause the battery cell to enter uncontrollable thermal runaway and start a fire.

[0020] A detrimental consequence associated with nonuniform lithium metal deposition is the continuous formation and decomposition of parasitic surface degradation products at the lithium metal-electrolyte interface, commonly referred to as the solid electrolyte interphase (SEI). SEI formation results from the thermodynamic instability of typical electrolyte solvents at battery operating voltages. Particularly at the anode, reduction reactions dominate, leading to first cleavage of electrolyte solvent molecules, then bonding with nearby Li ions, ultimately resulting in the precipitation of insoluble, irreversible Li-containing compounds. Similar to isolated Li metal, SEI compounds are also electrochemically inactive and contribute to capacity fade. In state-of-the-art LIBs, SEI forms on the surface of graphite anodes during the first few charging cycles, but its electrically insulating properties significantly suppress its formation during subsequent cycles. In graphite anodes, the relatively small volume change (approximately 10%) upon lithiation / delithiation, combined with the stability of the host graphite lattice itself, allows the SEI at the anode-electrolyte interface to remain largely intact throughout the cycle life of the LIB. However, the deposition of lithium metal is unpredictable and non-uniform, resulting in large changes in the volume of the SEI on the lithium metal surface with each charge-discharge cycle, leading to rapid breakdown of the SEI.

[0021] Furthermore, a practical drawback of lithium metal anodes is that lithium metal deposition affects the overall cell geometry. At the beginning of a LIB's life, all available lithium is stored in the cathode. In lithium metal anode battery cell designs, the initial anode is a bare foil current collector. Then, during the first charge of the battery, lithium is transported from the cathode through the electrolyte to the current collector surface, where it is electrodeposited as a lithium metal layer. During this process, the volume of the cathode material changes only slightly, but the deposited lithium metal contributes to an additional thickness of several microns per anode-cathode pair. For example, for a cathode with an areal capacity of approximately 3 mAh / cm2, assuming a bulk density of lithium metal, the lithium metal thickness at full charge would be approximately 15 μm. However, in most cases, the lithium metal thickness actually exceeds this value due to the non-uniform and low-density morphology of lithium metal, as mentioned above. Therefore, in a battery cell consisting of multiple stacked anode-cathode pairs, the overall battery cell thickness can increase by tens to hundreds of microns during the charging process. Given that typical battery cell housings are not designed with sufficient volume to accommodate such an increase in thickness, lithium metal deposition presents a practical barrier.

[0022] The morphology of electrodeposited lithium metal is highly dependent on the current density during deposition. For example, at deposition current densities of approximately 0.1 mA / cm2, lithium metal can be deposited relatively uniformly laterally, but at current densities above 1 mA / cm2, dendritic growth begins. When a Li metal anode is combined with a cathode with an areal capacity of greater than 3 mAh / cm2, a charge current density of 0.1 mA / cm2 corresponds to a C / 30 charge rate, which is 1 / 120th of the minimum fast charge rate of 4C required for EVs. Furthermore, electrodeposited Li metal layers with a 4C fast charge rate are typically achieved when a moderate compressive stress is applied to the entire cell stack. A support structure rigid enough to withstand this pressure significantly increases the mass, reducing the specific energy gain from using a lithium metal anode. Furthermore, the application of this pressure increases costs and reduces the economic viability of lithium metal anodes.

[0023] One way to promote lateral growth while maintaining a relatively low Li metal electrodeposition current density is to increase the effective surface area of ​​the current collector. For example, a highly textured current collector can have an effective surface area that is orders of magnitude larger than the planar surface area. Such a current collector can be used when the effective current density is within an acceptable range for lateral growth of Li metal (e.g., 0.1 mA / cm). 2 (less than 1000 kJ / cm2) to support high charge rates from cathodes with planar capacities in excess of 3 mAh / cm2.

[0024] Furthermore, by providing a stable, volume-unchanging scaffold onto which a thin layer of Li metal is plated, the textured 3D current collector effectively eliminates the problem of cell expansion during each charging cycle.

[0025] To date, research into developing textured current collectors for lithium metal deposition has primarily focused on porous metal "foams." Such structures are typically fabricated by etching solid, planar metal foils to form highly porous textured microstructures or by coating foams of other materials (e.g., carbon) with a thin metal layer. While such metal foams have shown some success in suppressing dendrite growth during Li metal deposition, they do not provide the most efficient or optimal structures. While such foams typically have high porosity, their relatively large average pore size still results in low effective surface area as a function of foam thickness. Ultimately, these foams themselves tend to be several dozen to several hundred microns thick, significantly reducing the effective volumetric energy density of the resulting battery cell. Furthermore, foam fabrication adds a new step to the battery manufacturing process and can often be a costly technique (e.g., when the foams are produced by high-temperature pyrolysis processes).

[0026] In addition to ultimately leaving insufficient surface area for lithium deposition, the thickness of the lithium metal layer on all surfaces within the foam can exceed several hundred nanometers upon full charge. Such repeated volume changes of the lithium metal layer can still cause any nascent SEI formed on the lithium metal surface during previous cycles to collapse, thereby exposing fresh lithium metal surface for new SEI formation during each cycle. This results in accelerated capacity fade and reduced coulombic efficiency.

[0027] Nanoparticles of various materials and shapes (e.g., rod-shaped, spherical, wire-shaped) have excellent surface-to-mass and surface-to-volume ratios. Therefore, three-dimensional nanoparticle structures, compared to metal foam structures, can provide a relatively high-surface-area substrate suitable for relatively uniform lateral lithium metal deposition. Such structures essentially provide a "seed layer" for lithium metal deposition that can be deposited on a separate, planar current collector, while also providing a low-resistance electrical connection to the current collector itself. The nanoparticles used to construct such seed layers can be metallic (i.e., have low bulk electrical resistivity) and can be packed with a fairly high packing density within the seed layer, while maintaining sufficient void volume between particles to ensure space for lithium metal deposition and a self-limiting SEI. As a result, the seed layer structures described herein can maximize the surface area available for lithium deposition while minimizing the thickness of the seed layer structure. The seed layer structure also provides a minimum pore volume to accommodate the growth of the lithium metal layer and associated SEI, while simultaneously minimizing the thickness required for the lithium metal layer at full charge to prevent SEI collapse due to volumetric growth of the lithium metal layer.

[0028] Application of nanoparticles to the current collector surface can be achieved by preparing a stable colloidal suspension in a solvent, where the nanoparticles are surface-modified with appropriate ligands, essentially creating a nanoparticle "ink." Such inks can be tailored to high nanoparticle solids contents without sacrificing colloidal stability. In some instances, the ink can comprise appropriate molecular precursors, which, upon post-treatment, produce a porous, thin, solid film comprising the nanoparticles. Once a suitable ink is formed, it can be applied to the current collector surface using coating techniques used to apply solutions or slurries to flat substrates, such as spray coating or slot-die coating. In various instances, applying the ink to the current collector surface can be accomplished using techniques used to apply graphite active material to anode current collectors in existing LIB processes, such as slot-die slurry casting. As a result, from a manufacturing perspective, existing graphite slot-die coating processes can be repurposed to deposit colloidal nanoparticle inks or molecular precursor inks instead of graphite slurries. The nanoparticle-based seed layer described herein has distinct advantages over other textured 3D current collectors because the deposition of the nanoparticle seed layer can be performed using existing standard LIB manufacturing equipment. Meanwhile, the application of foam-based nanostructures or microstructures adds additional functionality to existing systems used in the fabrication of lithium-ion batteries, including graphite-coated electrodes.

[0029] Ligands, which functionalize the surface of nanoparticles and allow them to disperse in a solvent as a colloidal solution, also play another important role in the formation of the nanoparticle seed layer: they act as pore-forming species. When nanoparticle ink is applied to the surface of a current collector, a "wet" film consisting of ligand-functionalized nanoparticles and residual solvent remains immediately after application. Once the solvent evaporates, a "dry" film consisting of a stack of ligand-functionalized nanoparticles remains. This dry film can then be subjected to a moderate heat treatment, which can cause the nanoparticles to bond or "neck," i.e., form small sintered interparticle connections. This necking is possible because the surface ligands are typically very unstable on the nanoparticle surface. At the same time, the nanoparticles can also form small sintered connections with the underlying current collector. Once the nanoparticles form sintered connections with each other and with the underlying current collector, they form a mechanically stable matrix. The ligands can then be removed by another heat or chemical treatment, leaving behind voids. After removal of the ligands, a porous, free-standing nanoparticle matrix (the "seed layer") remains on top of the current collector, which can be used as a substrate for lithium metal deposition.

[0030] Additionally, in one or more examples, the nanoparticles may be fused and sintered to themselves and the underlying current collector to form a porous, free-standing nanoparticle matrix. In at least some examples, the nanoparticle matrix may be formed from nanoparticles produced from an ink containing molecular precursors.

[0031] The drawback of using copper as a current collector in lithium-ion batteries is its mass density of approximately 9 g / cm 3 The mass density of copper can reduce the gravimetric energy density of a battery when it is used as a current collector in place of a less dense material. Therefore, any lithium-ion battery design that can reduce the amount of copper required or replace copper with another material with similar physical properties and a lower mass density would provide an advantage in cell-level gravimetric energy density compared to the state-of-the-art. However, copper-like materials with the properties required for lithium-ion battery current collectors are typically less abundant than copper and too costly to be used on a large scale.

[0032] Currently, the minimum amount of copper that can be used as an anode current collector in lithium-ion batteries is determined by the minimum thickness at which copper can be easily processed into foil while remaining a practical substrate for active material deposition. Although copper can be processed into foils as thin as about 6 microns, further reductions in thickness impair its processability using state-of-the-art "roll-to-roll" equipment.

[0033] One way to further reduce the copper content in lithium-ion batteries is to deposit copper as a thin film of less than 6 microns on a low-density substrate such as a polymer, which may create a lightweight composite copper-polymer current collector that can be used in place of a high-density current collector composed entirely or mostly of copper foil. The use of a composite copper-polymer current collector may take advantage of the high electrical conductivity of copper and the low mass density of an appropriately selected polymer.

[0034] Metallized polymer substrates are particularly popular in food packaging applications, where the metal film enhances moisture and light barrier properties, thereby reducing the rate of spoilage of the packaged food. Examples of metallized polymer packaging materials include thin aluminum films deposited onto polyethylene or polypropylene substrates using a roll-to-roll vacuum deposition process.

[0035] In such applications, the thickness of deposited aluminum films ranges from single digit angstroms to tens of nanometers. This thickness provides sufficient barrier properties, desirable for food packaging applications. However, when used as battery current collectors, copper or aluminum films are typically hundreds of nanometers to several microns thick to ensure the electrical and thermal conductivity required for typical battery operation. Depositing such thick metal layers onto polymer substrates at high rates using vacuum deposition methods is particularly challenging because the impinging metal flux imposes a significant thermal load on the polymer substrate. This high thermal load typically raises the temperature of the polymer above its glass transition temperature, even when active cooling is simultaneously applied to the deposition zone. As a result, evaporation and similar high-energy physical vapor deposition methods (e.g., sputtering) are not particularly suitable for producing metallized polymer current collectors for battery applications.

[0036] Therefore, there is a need for new battery electrode designs and more feasible current collector manufacturing methods that allow metals such as copper and aluminum to be applied in the required amounts to the surface of polymer films without damaging them, so that the resulting composite metal-polymer substrates can be used as lightweight current collectors in lithium-ion batteries.

[0037] When applied to polymer substrates for food packaging, metal thin films are free of defects and pinholes that inhibit microbial growth due to moisture and light penetration. Consequently, vacuum deposition is particularly suitable for such film deposition, as the high mobility of surface adatoms during the deposition process allows for the realization of high-density thin films. Current collectors for lithium-ion batteries, on the other hand, do not require high film density. Instead, they possess sufficient electrical and thermal conductivity for battery operation. Therefore, metal films with much lower density or even porous structures may be suitable for use as current collectors for lithium-ion batteries, as long as they have sufficient electrical and thermal conductivity.

[0038] One method for depositing thick metal films onto polymer substrates quickly and with minimal thermal load is to deposit a film of a colloidal suspension of metal particles (i.e., a metal particle "ink") onto the polymer substrate using solution-phase thin-film deposition techniques such as slot-die coating or spray coating. The solvent is then evaporated from the ink, leaving behind a film of metal particles. Such metal particle films can be deposited to a thickness of tens of microns in a single pass.

[0039] Such ink-based approaches to producing conductive thin films typically produce films with significant porosity, but as mentioned above, as long as the porous material has sufficient electrical and thermal conductivity, it can be used as a current collector in lithium-ion batteries.

[0040] While some existing techniques involve fabricating porous metal films on polymer substrates via solution-phase coating of metal nanoparticle inks and using porous metal-polymer composite substrates as current collectors for lithium metal anodes, the embodiments described herein describe the use of composite substrates as current collectors for a variety of battery chemistries.

[0041] Furthermore, ink-based current collector deposition processes feature the ability to directly mix an ink containing current collector metal particles into an active material slurry. This active material / metal ink composite slurry can then be co-cast onto a substrate, such as a polymer film. In various examples, both the cathode and anode active materials are first formulated into a slurry containing a binder, conductive additive, and solvent, which is then cast onto the surface of a current collector foil using a slot-die deposition method to create a battery electrode. Therefore, by directly mixing the metal ink into the electrode active material slurry, both inks can be applied to a given substrate in a single deposition step, thereby eliminating the need for a separate metal ink deposition step to form the current collector. This approach is particularly advantageous when the total mass fraction of the metal ink required is low relative to the active material content, or when the overall electrode thickness is thin (e.g., for high-energy-density active materials).

[0042] The ink-based current collector fabrication method offers the added advantage of allowing for fine-tuning of the porosity and composition of the final metal layer. For example, increasing porosity can further reduce the overall metal mass of the current collector, thereby further reducing cell weight, and mechanical properties such as intrinsic stress in the metal layer film can be tailored in porous films in ways not possible with dense vapor-deposited thin films. Similarly, current collector inks composed primarily of metal components can also contain additives, such as binders or conductive additives, to further improve the mechanical and electrical properties of the current collector. For example, additives such as binders can improve the flexibility and adhesion of the metal layer and improve the roll-to-roll processability of the composite current collector. On the other hand, dense vapor-deposited metal films are composed solely of the target metal and have limited ability to incorporate secondary or tertiary components into the film. Binders can also be incorporated to improve adhesion between the current collector and the active material deposited thereon.

[0043] Another advantage of porous metal layers within current collectors is their ability to accommodate the volumetric expansion of the active material during cell operation. Anode active materials, such as silicone, are known to expand in volume by approximately 300% upon full lithiation. To accommodate this expansion, other cell components often shrink accordingly. As a result, unwanted pores in the microporous separator between the anode and cathode often become blocked, inhibiting ionic conduction through the electrolyte. By introducing porosity into the current collector, cells can be engineered to preferentially shrink in the current collector, so that electrolyte removal does not adversely affect cell performance.

[0044] Introducing porosity into the underlying polymer substrate is also an advantageous approach. The technology of introducing pores with various pore volumes, porosities, and pore sizes into polymer membranes is well established in many industries and applications, such as polymer membranes and battery separators. In the case of metal-polymer composite current collectors, the porous polymer substrate can also be engineered to preferentially accommodate the volume expansion of the active material, thereby enabling cell designs in which the total cell thickness remains constant during cycling, even when active materials such as silicone are used.

[0045] Finally, ink-based deposition of metal films onto polymer substrates imposes a much lower thermal load on the underlying polymer than vacuum deposition of the same amount of metal. As a result, ink-based deposition processes significantly broaden the range of polymer compositions, including polymers with low glass transition temperatures (e.g., glass transition temperatures below 100°C). Examples include polyethylene, polyethylene glycol, polyester, polyethylene terephthalate, polypropylene, acrylates, and polyvinyl chloride. Polymers with intermediate glass transition temperatures (e.g., glass transition temperatures above 100°C and below 200°C), such as polyimides and aromatic polyamides, can also be used.

[0046] In some examples, the formation of a metal film can result from the controlled decomposition of reagents within an ink deposited on a polymer substrate. In these embodiments, the ink can be composed of a mixture of dissolved chemical reagents (such as a metal salt solution) rather than a preformed colloidal suspension of metal particles. After applying such an ink to a polymer substrate, the substrate undergoes additional thermal and / or chemical treatments to decompose the ink into a film composed of porous metal. In some embodiments, the ink can include not only a solution of metal salts but also metal particles.

[0047] The ability to precisely tailor the resistivity of the metal layer in metal-polymer current collectors also provides unique safety benefits to the resulting batteries, such as reduced current density during short circuits. The primary cause of thermal runaway in lithium-ion batteries is an internal short circuit resulting from direct electrical contact between the anode and cathode. In such an event, the cell rapidly discharges through the short circuit, raising the cell temperature locally to the point of ignition. The magnitude of the current flowing during a short circuit in a lithium-ion battery is directly related to the resistivity of the current collector. That is, the thicker and more conductive the current collector, the higher the short-circuit current. Copper foil, typically processed to a minimum of 6 microns, does not provide sufficient resistance to substantially limit the current density during a short circuit. Reducing the copper thickness below 6 microns can reduce the short-circuit current density and prevent cell temperatures from rising high enough to cause thermal runaway. Unlike metal foil current collectors, metal-polymer composite current collectors allow for such low copper content.

[0048] When a lithium-ion battery short circuit occurs due to penetration of the cell casing by an external object (such as a nail), the primary limiting factor in short-circuit current density is the contact resistance between the external object and the current collector. Again, a porous current collector has fewer contact points between the current collector and the external object compared to a dense current collector, thereby increasing the contact resistance between the external object and the current collector and reducing the short-circuit current density.

[0049] Additionally, if the battery is heated to temperatures above recommended safety limits (e.g., due to a short circuit or excessive external heating), the metal-polymer current collector may have additional safety features to prevent further heating. For example, the metal or polymer layers within the metal-polymer current collector may have a high coefficient of thermal expansion ("high T"). c "), resulting in a high T c The material can break the sintered connections in the metal layers, thereby mitigating the short circuit current in the event of a short circuit. Examples of such high Tc materials include polymers such as polyethylene, polypropylene, polystyrene, and polyvinyl chloride. Each of these materials has a 50x10-6 K -1 Alternatively, the additive may melt or sublime at a threshold temperature in a manner that similarly inhibits electrical conduction between metal particles within the metal layer. Low-melting-point additives include polymers such as ethylene vinyl acetate, polyvinyl alcohol, and polycaprolactone. Each of these materials has a lower melting point than standard polyethylene / polypropylene separators (below 100-120°C), offering the advantage of interrupting the conductive pathway within the current collector before the separator melts and causes a short circuit between the anode and cathode. Other potential low-melting-point additives include polymers such as silicone and polyurethane. An example of an additive that sublimes at low temperatures is naphthalene, which can similarly inhibit the conductive pathway of the current collector during a thermal event. Notably, these additives are more easily incorporated into the metal layer when the metal is deposited as an ink, since the additive can be easily mixed into the ink, whereas it is likely impossible to incorporate these materials into the deposited metal. These additives are also more easily incorporated into metal inks than into base polymers. Another example of a material that can be added as an additive to metal inks is a flame retardant. Examples of flame retardant molecules include other inorganic molecules such as ammonium polyphosphate, ammonium sulfate, or sodium borate, as well as organic molecules such as melamine and pentaerythritol.

[0050] In at least some embodiments, in the case of thermal cycling, the melting point and / or T between the metal and the underlying polymer can be significantly different, even when the metal layer does not contain other additives. c The mismatch can create enough membrane stress to break the sintered connections between the metal particles. When the sintered connections between the metal particles break, the cell enters an "open circuit" state, which prevents further Joule heating from the short circuit current.

[0051] In at least some instances, the polymer substrate may be pretreated prior to deposition of the metal or metal active material ink to improve ink adhesion and / or wetting. Examples of pretreatment processes include ultraviolet (UV)-ozone, corona discharge, atmospheric pressure plasma, or chemical pretreatments such as rinsing with acidic or basic solutions or similar primers or etchants.

[0052] In one or more examples, the coated metal-polymer or coated metal-active material-polymer composite may be subjected to a post-deposition treatment ("post-treatment"). Such treatments may be used, for example, to aid sintering or improve electrical connections between metal particles. Examples include one or more heat treatments in various ambient atmospheres, such as nitrogen, oxygen, hydrogen, ozone, and / or mixtures thereof. Non-convective examples include optical flash sintering, spark plasma sintering, ultrasonic sintering, or microwave sintering.

[0053] In various examples, the adhesion between the metal layer or metal active material layer and the underlying polymer substrate can be improved by depositing a sealing film on the surface of the composite. Such a sealing film can be deposited using a solution-phase method. In at least some examples, solution-phase techniques used to deposit a sealing film on a polymer substrate can include those described in U.S. Pat. No. 10,985,360, which is incorporated herein by reference in its entirety. Such a sealing film can have a primarily inorganic or organic composition. In one or more examples, the sealing film can be a composite film comprising an inorganic layer and an organic layer. Examples include organic coatings (polyamides, polyimides, polyethylene glycols) and inorganic coatings (metal oxides, metal phosphates, metal sulfates). In at least some examples, the sealing film can also prevent parasitic electrochemical side reactions from occurring at the interface between the metal or metal active material and the electrolyte during battery operation.

[0054] The embodiments described herein relate to methods, processes, formulations, techniques, systems, and devices related to the deposition of current collector layers in lithium-ion battery electrodes. The embodiments described herein address shortcomings of previously practiced techniques for the deposition of lithium onto current collector layers and the use of copper and other metals as current collector materials.

[0055] FIG. 1 illustrates a flow diagram of an exemplary process 100 for manufacturing a porous current collector layer for a lithium-ion battery, according to one or more examples. The process 100 may include, in operation 102, providing a substrate for a battery electrode, such as a lithium-ion battery electrode. In one or more examples, the substrate may be included in an anode of a lithium-ion battery. Furthermore, the substrate may be formed into at least one of a sheet or a foil. In at least some examples, the substrate may be configured to be processed using a roll-to-roll conveying apparatus.

[0056] In one or more examples, the substrate can comprise one or more polymeric materials. In various examples, the one or more polymeric materials can have a glass transition temperature of 50° C. or less, 80° C. or less, 100° C. or less, 120° C. or less, 150° C. or less, 180° C. or less, about 200° C. or less, about 210° C. or less, about 220° C. or less, about 230° C. or less, about 240° C. or less, about 250° C. or less, about 260° C. or less, about 270° C. or less, about 280° C. or less, about 290° C. or less, about 300° C. or less, about 325° C. or less, or about 350° C. or less. For example, the one or more polymeric materials may have a glass transition temperature of about 50° C. to about 350° C., about 80° C. to about 250° C., about 100° C. to about 200° C., about 200° C. to about 300° C., about 200° C. to about 240° C., about 260° C. to about 300° C., or about 230° C. to about 270° C. In one or more illustrative examples, the one or more polymeric materials may include at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyether ether ketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate.

[0057] In at least some examples, the substrate can have some degree of porosity. Illustratively, the substrate can comprise at least about 5% by volume pores, at least about 10% by volume pores, at least about 15% by volume pores, at least about 20% by volume pores, or at least about 25% by volume pores. Furthermore, the substrate can comprise no more than about 65% by volume pores, no more than about 60% by volume pores, no more than about 55% by volume pores, no more than about 50% by volume pores, no more than about 45% by volume pores, or no more than about 40% by volume pores. In one or more illustrative examples, the substrate can have between about 5% by volume and about 65% by volume pores, between about 5% by volume and about 60% by volume pores, between about 10% by volume and about 55% by volume pores, between about 15% by volume and about 50% by volume pores, or between about 20% by volume and about 45% by volume pores. In various examples, the pores can be spherical. Further, the pores may have a diameter of about 1 nanometer (nm) to about 500 nm, about 10 nm to about 400 nm, about 50 nm to about 250 nm, about 100 nm to about 200 nm, about 200 nm to about 400 nm, or about 1 nm to about 100 nm. 50 may have:

[0058] Prior to performing additional treatment operations, one or more surfaces of the substrate may be pretreated. For example, the substrate may be subjected to one or more pretreatment operations that may improve the adhesion of one or more substances deposited on the substrate. Additionally, the one or more pretreatment operations may improve the wettability of one or more substances deposited on the substrate. In one or more examples, the substrate may be subjected to one or more pretreatment operations that may improve at least one of the adhesion or wettability of one or more inks deposited on the substrate. In one or more illustrative examples, the one or more pretreatment processes applied to the substrate may include an ultraviolet (UV) ozone treatment that includes exposing the substrate to an ozone-generating UV source. In one or more additional illustrative examples, the one or more pretreatment processes applied to the substrate may include a corona discharge. In one or more further illustrative examples, the one or more pretreatment processes may include an atmospheric pressure plasma treatment. In still other illustrative examples, the one or more pretreatment processes may include one or more chemical pretreatments, such as rinsing one or more surfaces of the substrate with one or more solutions. In at least some examples, the one or more solutions may include at least one of an acidic solution, a basic solution, a primer, or an etching solution. In various examples, the one or more pretreatment processes may be carried out in an environment having a temperature of about 15° C. to about 35° C. and a pressure of about 95 kilopascals (kPa) to about 110 kPa.

[0059] In operation 104, the process 100 may include forming a layer including one or more conductive materials on a substrate. In various examples, the one or more conductive materials may include at least one of copper, copper alloy, aluminum, aluminum alloy, titanium, titanium alloy, nickel, nickel alloy, or stainless steel. Additionally, the one or more conductive materials may be comprised of particles having a spherical morphology. In these circumstances, the layer may have a diameter of about 10 nm to about 100 nm, about 10 nm to about 50 nm, about 20 nm to about 60 nm, about 30 nm to about 70 nm, about 40 nm to about 80 nm, or about 50 nm to about 90 nm. 50Furthermore, the one or more conductive materials may be comprised of particles having a nanowire morphology. In one or more illustrative examples, the one or more conductive material particles having a nanowire morphology may have a length of about 1 micrometer to about 100 micrometers, about 5 micrometers to about 50 micrometers, about 10 micrometers to about 40 micrometers, about 30 micrometers to about 70 micrometers, or about 60 micrometers to about 100 micrometers. Furthermore, the one or more conductive material particles having a nanowire morphology may have a diameter of about 10 nm to about 200 nm, about 20 nm to about 150 nm, about 30 nm to about 100 nm, about 20 nm to about 50 nm, about 50 nm to about 100 nm, or about 75 nm to about 150 nm.

[0060] Additionally, the layer may have a thickness of about 20 micrometers or less, about 18 micrometers or less, about 15 micrometers or less, about 10 micrometers or less, about 8 micrometers or less, or about 5 micrometers or less. In one or more illustrative examples, the layer may have a thickness of about 1 micrometer to about 20 micrometers, about 2 micrometers to about 18 micrometers, about 3 micrometers to about 15 micrometers, about 2 micrometers to about 10 micrometers, about 5 micrometers to about 12 micrometers, or about 10 micrometers to about 20 micrometers.

[0061] Additionally, the layer may have a porosity measurement of at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50% by volume. In various examples, the layer may have between about 5% and about 60% by volume pores, between about 10% and about 50% by volume pores, between about 15% and about 40% by volume pores, between about 5% and about 30% by volume pores, between about 30% and about 60% by volume pores, or between about 25% and about 50% by volume pores. In one or more examples, the pores in the layer may have diameters of 25 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, or 5 nm or less. In one or more illustrative examples, the pores in the layer may have a diameter of about 0.5 nm to about 25 nm, about 1 nm to about 20 nm, about 2 nm to about 15 nm, about 5 nm to about 20 nm, about 1 nm to about 10 nm, or about 10 nm to about 20 nm.

[0062] The layer may be formed on the substrate by performing one or more solution-phase coating processes. In one or more examples, the layer may be formed on the substrate by performing at least one of a slot-die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip-coating process. In one or more illustrative examples, the layer may be formed on the substrate by depositing a formulation characterized as an ink onto the substrate. The ink may include first particles composed of one or more conductive materials and one or more solvents. The one or more solvents may include one or more organic solvents. In various examples, the one or more solvents may include at least one of isopropyl alcohol, ethanol, methanol, tert-butanol, 1-butanol, 2-amino-2-methyl-1-propanol, amino-2-propanol, 2-methoxyethanol, ethylene glycol, dipropylene glycol monomethyl ether, diethylene glycol methyl ether, benzyl alcohol, pyridine, tetrahydrofuran (THF), hexane, toluene, or water.

[0063] In at least some examples, one or more heat treatments can be performed after depositing the ink on a substrate. The one or more heat treatments can be performed at temperatures of about 325°C or less, about 300°C or less, about 275°C or less, about 250°C or less, or about 225°C or less. For example, the one or more heat treatments can be performed at temperatures of about 75°C to about 325°C, about 100°C to about 200°C, about 150°C to about 250°C, or about 200°C to about 300°C. In various examples, the one or more heat treatments are performed in an environment containing one or more gases consisting of at least one of nitrogen, oxygen, hydrogen, ozone, or argon. In one or more illustrated examples, the one or more gases can be ionized.

[0064] In one or more examples, the layer can include one or more additional components that can be part of a battery electrode. For example, the layer can also include one or more electrode active materials. In various examples, the one or more electrode active materials can correspond to materials used in the anode of a lithium-ion battery. In one or more illustrative examples, the one or more electrode active materials can be selected from graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO2, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z, LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. Additionally, the layer may include one or more binder materials for binding the one or more electrode active materials with the one or more conductive materials. The one or more binder materials may include at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate. Furthermore, the layer may include one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles. When the layer includes one or more additional components, the ink used to form the layer may include first particles comprising one or more conductive materials, as well as at least one of second particles corresponding to the one or more electrode active materials, third particles corresponding to the one or more binder materials, or fourth particles corresponding to the one or more conductive additives. In this way, the current collector material and the electrode active material can be combined into a single layer formed on the polymer substrate.

[0065] Optionally, process 100 may include forming an additional layer in operation 106, the additional layer comprising one or more electrode active materials on the substrate. In these embodiments, the initial layer formed on the substrate comprising one or more conductive materials may comprise a current collector layer, and the additional layer may comprise an electrode active material layer. The active material layer may include one or more electrode active materials and, optionally, at least one of one or more bonding materials or one or more conductive materials similar to or identical to those described above in connection with the bonded current collector and active material layer. By way of example, the one or more additional electrode active materials may comprise one or more electrodes corresponding to the anode of a lithium-ion battery, and may include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al zO2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. Additionally, the active material layer may include at least one of one or more binder materials including at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, or one or more conductive additives including at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0066] In one or more examples, the active material layer can be formed on the current collector layer by performing an additional solution-phase coating process, including at least one of a slot-die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip-coating process. In various examples, the active material layer can be formed on the current collector layer by depositing an additional ink on the current collector layer. The additional ink can include one or more solvents and particles comprising one or more electrode active materials, particles comprising one or more binder materials, and / or particles comprising one or more conductive additives. The one or more solvents can include at least one of isopropyl alcohol, ethanol, methanol, tert-butanol, 1-butanol, 2-amino-2-methyl-1-propanol, amino-2-propanol, 2-methoxyethanol, ethylene glycol, dipropylene glycol monomethyl ether, diethylene glycol methyl ether, n-methylpyrrolidone, benzyl alcohol, pyridine, tetrahydrofuran (THF), hexane, toluene, or water. In one or more exemplary embodiments, the active material binder may include at least one of PVDF, polyacrylic acid, carboxymethyl cellulose, or styrene butadiene rubber. In one or more additional exemplary embodiments, the active material conductive additive may include at least one of carbon black or carbon nanotubes. Deposition of the additional ink onto the current collector layer may be followed by one or more heat treatments performed at temperatures of about 325°C or less, about 300°C or less, about 275°C or less, about 250°C or less, or about 225°C or less. Additionally, the one or more additional heat treatments may be performed in one or more gases that can be ionized. In one or more illustrated examples, the one or more gases may include at least one of nitrogen, oxygen, hydrogen, or argon.

[0067] Furthermore, a sealing film may be deposited on at least one of the one or more conductive materials or composite conductive material-active material composites comprising one or more conductive materials and one or more electrode active materials. The sealing film may improve adhesion of the conductive particles, active material particles, or conductive particle-active material composites to at least one substrate. In one or more examples, the sealing film may include at least one of one or more organic materials or one or more inorganic materials. In one or more additional examples, the sealing film may include a composite film including multiple layers, including one or more first layers comprising one or more organic materials and one or more second layers comprising one or more inorganic materials. In at least some examples, the sealing film may include alternating layers of organic and inorganic materials. In one or more illustrative examples, the sealing film may include polyamide, polyimide, polyethylene glycol, one or more metal oxides, one or more metal phosphates, one or more metal sulfates, one or more metal cones, or one or more combinations thereof. In various examples, the sealing film may reduce or prevent electrochemical side reactions between the conductive materials and / or the conductive material-active material composites and the electrolyte present in the battery. The encapsulating thin film can have a thickness of about 1 nm to about 1000 nm, about 10 nm to about 500 nm, about 50 nm to about 250 nm, about 10 nm to about 100 nm, or about 100 nm to about 500 nm.

[0068] In at least some examples, the sealing film can be formed using one or more solution-phase techniques. For example, the sealing film can be formed by exposing at least one of one or more conductive materials or conductive material-active material composites formed on a substrate to one or more solutions. Illustratively, the sealing film can be formed by at least one of dipping, spraying, slot-die coating, bath coating, or gravure roller coating. In one or more illustrative examples, the sealing film can be formed using a roll-to-roll conveying apparatus in which a substrate having one or more layers comprising at least one of one or more conductive materials or one or more conductive material-active material composites is immersed in one or more reaction chambers. In various examples, the polymer substrate can be formed as a continuous or semi-continuous sheet. After forming one or more layers comprising at least one of one or more conductive materials or one or more conductive material-active material composites, the conveying apparatus can convey the sheet to one or more reaction chambers containing one or more solutions containing at least some of the components of the sealing film. In one or more examples, the transport device may immerse a substrate having one or more conductive materials or conductive material-active material composites deposited thereon into multiple reaction chambers where one or more layers of a sealing thin film are formed in each reaction chamber.

[0069] In various examples, one or more post-deposition treatments may be performed after depositing one or more layers on a substrate. For example, one or more post-deposition treatments may be performed after depositing one or more layers including one or more conductive materials on a substrate. In one or more additional examples, one or more post-deposition treatments may be performed after forming one or more composite metal active material layers on a substrate. In at least some examples, the one or more post-deposition treatments may improve electrical connections between metal particles deposited on the substrate. Illustratively, the one or more post-deposition treatments may induce and / or promote sintering between metal particles deposited on the substrate. In one or more examples, the one or more post-deposition treatments may include one or more heat treatments. In one or more illustrated examples, the one or more post-deposition treatments may include at least one of optical flash sintering, spark plasma sintering, ultrasonic sintering, or microwave sintering.

[0070] Additionally, at least one of the layers deposited in operation 104 or the additional layers in operation 106 may include additives that enhance the safety of the battery. For example, at least one of the layers or additional layers may include one or more flame retardants and / or one or more thermal management additives that may reduce or prevent overheating of the lithium-ion battery. In one or more illustrative examples, at least one of the layers or additional layers may include one or more flame retardant additives selected from at least one of other inorganic molecules, such as ammonium polyphosphate, ammonium sulfate, sodium borate, or organic molecules, such as melamine and pentaerythritol. In one or more additional illustrative examples, at least one of the layers or additional layers may include at least 30×10 -6 K -1 , at least 40 x 10 -6 K -1 , at least 50 x 10 -6 K -1 , at least 60 x 10 -6 K -1 , at least 70 x 10 -6 K -1 , at least 80 x 10 -6 K -1 , at least 90 x 10 -6 K -1 , or at least 100×10 -6 K -1 In various examples, at least one of the layers or additional layers may include one or more first thermal management additives comprised of one or more polymeric materials. By way of example, at least one of the layers or additional layers may include at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, or polyvinyl chloride.

[0071] At least one of the layers or additional layers may include one or more second thermal management additives having a melting point of 130°C or less, 120°C or less, 110°C or less, 100°C or less, or 90°C or less. In various examples, the one or more second thermal management additives may interrupt conductive paths in current collectors of lithium-ion batteries. For example, at least one of the layers or additional layers may include one or more second thermal management additives composed of one or more polymeric materials or foams having a melting point lower than that of polyethylene, polypropylene, or a combination thereof. By way of example, at least one of the layers or additional layers may include one or more second thermal management additives composed of at least one of ethylene vinyl acetate, polyvinyl alcohol, polycaprolactone, silicone, polyurethane, or naphthalene. The one or more second thermal management additives may also include one or more materials that sublimate at temperatures of 130°C or less, 120°C or less, 110°C or less, 100°C or less, or 90°C or less. In one or more further illustrative examples, the one or more second thermal management additives may include naphthalene.

[0072] By forming a porous current collector layer or a porous layer combining current collector particles and electrode active material particles, lithium ion batteries can be produced that have advantages over existing lithium ion batteries. For example, by reducing the amount of copper present in the current collector layer, the lithium ion batteries described herein can increase the gravimetric energy density relative to existing lithium ion batteries while providing sufficient electrical conductivity to facilitate the transport of lithium ions between the electrodes of the lithium ion battery. Furthermore, by increasing the porosity of at least one of the current collector layer or the combined current collector and electrode active material layer, the effects of expansion of the active material that occurs during use of the lithium ion battery can be reduced. That is, by increasing the porosity of the current collector layer and / or electrode active material of the lithium ion batteries described herein, lithium ion transport between the electrodes can be improved compared to existing lithium ion batteries, where expansion of the electrode active material more restricts lithium ion transport.

[0073] 2 illustrates a device 200 including a substrate 202, a porous current collector layer 204, and an electrode active material layer 206 disposed on the current collector layer 204, which is comprised of spherical conductive particles 208, according to one or more examples. In one or more examples, the device 200 may comprise a lithium-ion battery. Furthermore, the substrate 202 may include at least one of a sheet or foil comprised of one or more polymeric materials, including at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyetheretherketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate. Furthermore, the spherical conductive particles 208 may comprise at least one of copper, aluminum, titanium, nickel, or stainless steel. The current collector layer 204 may have pores 210 comprising at least 5% by volume of the current collector layer 204.

[0074] The electrode active material layer 206 can include anode active material particles 212, binder particles 214, and conductive additive particles 216. The anode active material particles 212 can be selected from graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. The binder material 214 may comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, and the conductive additive particles 216 may comprise at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0075] 3 shows a device 300 including a substrate 302 and a layer 304 comprised of spherical conductive particles 306 and electrode active material particles 308, according to one or more examples. In one or more examples, device 300 may include a lithium-ion battery. Additionally, substrate 302 may include at least one of a sheet or foil comprised of one or more polymeric materials including at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyether ether ketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate.

[0076] Layer 304 may combine a current collector and an electrode active material layer. The spherical conductive particles 306 may comprise at least one of copper, aluminum, titanium, nickel, or stainless steel. In addition, the electrode active material particles 308 may be graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. Layer 304 may also include a binder material 310 that may comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, and conductive additive particles 312 that may comprise at least one of carbon black particles, carbon nanotubes, or graphite particles. In various examples, layer 304 may have pores 314 that comprise at least 5% by volume of layer 304.

[0077] FIG. 4 illustrates a device 400 including a substrate 402, a porous current collector layer 404, and an electrode active material layer 406 composed of conductive nanowires 408 disposed on the current collector layer 404, according to one or more examples. In one or more examples, the device 400 may include a lithium-ion battery. Furthermore, the substrate 402 may include at least one of a sheet or foil composed of one or more polymeric materials including at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyether ether ketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate. Furthermore, the spherical conductive particles 408 may comprise at least one of copper, aluminum, titanium, nickel, or stainless steel. The current collector layer 404 may have pores 410 comprising at least 5% by volume of the current collector layer 404.

[0078] The electrode active material layer 406 can include anode active material particles 412, binder particles 414, and conductive additive particles 416. The anode active material particles 412 can be selected from graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. The binder material 414 may comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, and the conductive additive particles 416 may comprise at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0079] 5 shows a device 500 including a substrate 502 and a layer 504 comprised of conductive nanowires 506 and electrode active material particles 508, according to one or more examples. In one or more examples, device 500 may include a lithium-ion battery. Additionally, substrate 502 may include at least one of a sheet or foil comprised of one or more polymeric materials including at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyetheretherketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate.

[0080] Layer 504 may combine a current collector and an electrode active material layer. The spherical conductive particles 506 may comprise at least one of copper, aluminum, titanium, nickel, or stainless steel. In addition, the electrode active material particles 508 may be graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. Layer 504 may also include a binder material 510 that may comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, and conductive additive particles 512 that may comprise at least one of carbon black particles, carbon nanotubes, or graphite particles. In various examples, layer 504 may have pores 514 that comprise at least 5% by volume of layer 504.

[0081] FIG. 6 illustrates a device 600 including a porous substrate 602, a porous current collector layer 604, and an electrode active material layer 606 comprised of spherical conductive particles 608 disposed on the current collector layer 604, according to one or more examples. In one or more examples, the device 600 may include a lithium-ion battery. Furthermore, the substrate 602 may include at least one of a sheet or foil comprised of one or more polymeric materials including at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyetheretherketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate. In various examples, the substrate 602 may have pores 610 comprising at least 5% by volume of the substrate 602. Furthermore, the spherical conductive particles 608 may comprise at least one of copper, aluminum, titanium, nickel, or stainless steel. The current collector layer 604 may have pores 612 comprising at least 5% by volume of the current collector layer 604.

[0082] The electrode active material layer 606 can include anode active material particles 614, binder particles 616, and conductive additive particles 618. The anode active material particles 614 can be selected from graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z, LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiVO5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients. The binder material 616 may comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate, and the conductive additive particles 618 may comprise at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0083] FIG. 7 is a diagram of a process 700 for forming a nanoparticle seed layer on a surface of a current collector layer. The process 700 may include an operation 702 of applying an ink 704 to a surface 706 of a current collector layer 708. In one or more illustrative examples, the ink 704 may be applied to the surface 706 of the current collector layer 708 by a solution-phase thin-film coating process. In one or more illustrative examples, the solution-phase coating process may include at least one of a slot-die coating process, a spray coating process, an aerosol coating process, a gravure coating process, a comma coating process, or a dip coating process. The current collector layer 708 may comprise a metallic material. For example, the current collector 708 may comprise at least one of copper, a copper alloy, aluminum, an aluminum alloy, titanium, a titanium alloy, nickel, a nickel alloy, or stainless steel. In one or more additional examples, the current collector layer 708 may comprise one or more polymeric materials. In various examples, current collector 708 may comprise at least one of polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate. In one or more further examples, current collector layer 708 may be composed solely of one or more polymeric materials. In yet other examples, current collector layer 708 may include one or more metallic materials laminated onto one or more polymeric materials. In one or more illustrative examples, current collector layer 708 may comprise a foil.

[0084] The ink 704 may include a plurality of nanoparticles 710. One or more ligands 712 may be attached to each nanoparticle 710. Each combination of nanoparticles 710 and one or more ligands 712 may result in a ligand-functionalized nanoparticle 714 disposed within the ink 704. The ink 704 may also include a solvent in which the nanoparticles 710 are dispersed. In one or more examples, the ink 704 may be applied to both sides of the current collector layer 708. In one or more additional examples, the ink 704 may be applied to one side of the current collector layer 708. In at least some examples, the ink 704 may include one or more conductive materials and one or more polymeric materials. The one or more conductive materials may include one or more metallic materials. The one or more polymeric materials may impart adhesive and / or cohesive properties to the ink 704.

[0085] Important design parameters for the ink 704 can include the nanoparticle material, size, and shape, as well as the composition and size of the nanoparticle surface functionalizing ligands. Additionally, the solids content of the nanoparticles 710 and associated ligands 712 within the ink 704 is also an important variable. For example, the size of the nanoparticles 710 can vary from 0.5 nanometers (nm) to 500 nm, 0.5 nm to 100 nm, 100 nm to 250 nm, 50 nm to 300 nm, 250 nm to 500 nm, 200 nm to 400 nm, or 300 nm to 500 nm for spherical nanoparticles. The size of the ligands 712 may be characterized in terms of molecular weight, and may range, for example, from 20 Da to 10 kDa, 10 Da to 1 kDa, 100 Da to 500 Da, 500 Da to 1500 Da, 1 kDa to 10 kDa, 5 kDa to 10 kDa, 1 kDa to 5 kDa, 2 kDa to 6 kDa, 3 kDa to 7 kDa, or 4 kDa to 8 kDa. The solids content of the ink 704 may range, for example, from 1% to 90%, where the solids content is defined as the sum of the mass of the nanoparticles 710 and the ligands 712 divided by the mass of the solvent. In one or more illustrative examples, the solids content may be 1% to 10%, 5% to 20%, 15% to 30%, 25% to 40%, 30% to 50%, 40% to 60%, 50% to 70%, 60% to 80%, 70% to 90%, 85% to 95%, or 90% to 99%.

[0086] In one or more examples, the ligands 712 may act as ion conductors, providing ionic conductivity in an electrolyte-like manner and therefore may not need to be removed from the "dried" film by techniques such as burning or dissolving. In various examples, the ligands 712 may include molecules with chelating groups that aid in the dispersion of the nanoparticles 710 in the solvent of the ink 704.

[0087] The nanoparticles 710 can include one or more metallic materials. The one or more metallic materials can be 1×10 -12The nanoparticles 710 may have a bulk resistivity of between 1 ohm-cm and 1 ohm-cm. Additionally, the nanoparticles 710 may include one or more semiconductor materials. The one or more semiconductor materials may have a bulk resistivity of between 1 ohm-cm and 1000 ohm-cm. In one or more further examples, the nanoparticles 710 may include one or more insulating materials. The one or more insulating materials may have a bulk resistivity of between 1000 ohm-cm and 10 -13 The nanoparticles 710 may have a bulk resistivity of ohm-cm. In one or more illustrative examples, the bulk resistivity may be measured at a temperature of 20°C to 30°C. In various examples, the nanoparticles 710 may not be metallic in nature, but may be semiconducting or electrically insulating. In one or more illustrative examples, the nanoparticles 710 may be characterized as being sufficiently conductive to avoid introducing excessive direct current (DC) internal resistance during operation of a battery comprising the nanoparticles 710. Despite the nanoparticles 710 being semiconducting or insulators, excessive DC current may not be present. In one or more examples, a battery in which the nanoparticles 710 are disposed may rely on the conductivity of the battery's lithium metal layer to ensure good power capacity, rather than relying on the conductivity of the nanoparticles 710. Semiconducting or insulating nanoparticles 710 may also be modified to have metallic properties through subsequent heat and / or chemical treatments applied to the final seed layer of nanoparticles 710, or through coating with a very thin metal layer. In various examples, the nanoparticles 710 may be made conductive by electroless plating with one or more metals.

[0088] In one or more examples, nanoparticles 710 of two different compositions can comprise a seed layer. For example, a first nanoparticle having a first composition can be used to provide structural integrity to the seed layer, while a second nanoparticle having a second composition can be used to provide sites for the catalytically controlled nucleation of Li metal. In one or more examples, nanoparticles 710 are “core-shell” nanoparticles, meaning that nanoparticles 710 can include two different materials. Illustratively, nanoparticles 710 can include an inner core composed of one or more first materials and an outer shell composed of one or more second materials disposed therearound. In these cases, the core can provide structural integrity to the seed layer, and the shell can provide sites for the catalytically controlled nucleation of Li metal. In one or more additional examples, nanoparticles 710 can have a spherical shape. Illustratively, nanoparticles 710 can have a multifaceted polyhedral shape.

[0089] The nanoparticles 710 can have dimensions of 1 Angstrom to 100 nm, 100 Angstroms to 100 nm, 100 Angstroms to 1 nm, 1 nm to 100 nm, 10 nm to 100 nm, 10 nm to 50 nm, or 50 nm to 100 nm. If the nanoparticles 710 have a spherical shape, the nanoparticles 710 can have a diameter of 1 Angstrom to 100 nm, 100 Angstroms to 100 nm, 100 Angstroms to 1 nm, 1 nm to 100 nm, 10 nm to 100 nm, 10 nm to 50 nm, or 50 nm to 100 nm.

[0090] The ink 704 may also include various additives. The additives may include one or more organic molecules. For example, the additives may be included in the ink 704 to further modify the porosity and packing density of the nanoparticles 710 in the seed layer. By way of example, the additives may include rheology modifiers or porosity modifiers.

[0091] The additive may not provide surface functionalization of the nanoparticles 710, as provided by the ligands 712. The additive may modify the porosity within the final seed layer. The additive is selected so as not to impair the colloidal stability of the ink 704 and may be easily removed from a film formed from the ink 704 by moderate thermal and / or chemical treatment. An example additive may include a polymer that promotes uniform self-assembly of the nanoparticles in a thin film, but may be relatively easily removed by burning or dissolving. In one or more additional examples, an additive may be introduced into the ink 704 to alter the rheological properties of the ink 704 and to improve coating of the ink 704 onto the surface 706 of the current collector layer 708 via one or more solution-phase coating techniques.

[0092] Process 700 may also include, in operation 716, performing one or more drying processes to remove at least a portion of the solvent included in ink 704 and produce a film 718. Film 718 may include ligand-functionalized nanoparticles 714.

[0093] After the drying process is performed in operation 716, one or more additional thermal treatment processes, one or more chemical treatment processes, or one or more thermal treatment processes and one or more chemical treatment processes may be performed. The one or more thermal treatments may include one or more thermal treatments. In one or more additional examples, the one or more thermal treatments may include non-convective heat treatments. In one or more illustrative examples, the non-convective heat treatments may include at least one of laser sintering, microwave sintering, or light flash sintering. Important variables associated with the thermal treatment process and / or chemical treatment process may include the heat treatment temperature and the ambient gas composition within the heat treatment chamber.

[0094] Further, in operation 720, process 700 may include performing at least one of a first thermal treatment process or a first chemical treatment process on film 718. In one or more examples, the first thermal treatment process and / or the first chemical treatment process may be performed in a chamber of the system used to generate the nanoparticle seed layer. In one or more examples, the first thermal treatment process may be performed at a temperature and duration sufficient to promote necking between nanoparticles without significantly reducing the overall surface area of ​​the nanoparticles through recrystallization. For example, the first thermal treatment process may be performed at a temperature between about 30°C and 650°C, 30°C and 100°C, 100°C and 300°C, 200°C and 500°C, 300°C and 650°C, 100°C and 200°C, 200°C and 300°C, 300°C and 400°C, 400°C and 500°C, or 500°C and 650°C. The first heat treatment may also be performed in an ambient environment that promotes necking of the nanoparticles without dramatically changing the composition of the nanoparticles. That is, the first heat treatment process may be performed in an environment that minimizes potential oxidation of the ligand-functionalized nanoparticles 710. In one or more illustrated examples, the first heat treatment may be performed in an environment comprised of nitrogen, oxygen, hydrogen, argon, or a combination thereof. Additionally, one or more gases may be ionized.

[0095] The first chemical treatment can include exposing the substrate to a bath containing a solution comprising the residual cleaning solvent and at least one chemical reagent. The bath can be heated to a temperature of 30° C. to 300° C. Additionally, the solution can remove residual organic molecules in the nanostructure seed layer via a dissolution or depolymerization mechanism.

[0096] Performing at least one of a first thermal treatment process or a first chemical treatment process can produce a modified film 722 that includes a number of intermediate nanoparticle clusters 724. Each intermediate nanoparticle cluster 724 can include a number of nanoparticles 710 that have fused together as a result of the first thermal treatment process and / or the first chemical treatment process. Each intermediate nanoparticle cluster 724 can also include a number of ligands 712 attached to fused groups of the nanoparticles 710. In various examples, at least one of the first thermal treatment process or the first chemical treatment process can alter at least one of the shape, volume, or area of ​​the nanoparticles 710, causing the nanoparticles 710 to fuse together to form the intermediate nanoparticle cluster 724.

[0097] In operation 726, process 700 may include performing at least one of a second thermal treatment process or a second chemical treatment process. The second thermal treatment process and / or the second thermal treatment process may produce a seed layer 728. The seed layer 728 may comprise a multiplicity of fused nanoparticles 730. Additionally, the seed layer 728 may be electrically conductive and may function as a current collector when disposed on a polymer substrate.

[0098] In various examples, a second heat treatment process and / or a second chemical treatment process can remove the ligands 712 from the intermediate nanoparticle clusters 724, producing fused nanoparticles 730. The seed layer can have a porosity of 1% to 99% by volume pores, 1% to 25% by volume pores, 5% to 20% by volume pores, 10% to 30% by volume pores, 20% to 30% by volume pores, 30% to 40% by volume pores, 40% to 50% by volume pores, 25% to 50% by volume pores, 50% to 75% by volume pores, 50% to 60% by volume pores, 60% to 70% by volume pores, 70% to 80% by volume pores, 80% to 90% by volume pores, or 90% to 99% by volume pores.

[0099] In one or more examples, at least a portion of the pores of the seed layer 728 can be filled with a solid electrolyte. In various examples, the pores of the seed layer 728 can be filled using liquid infiltration. The solid electrolyte can include a solid polymer electrolyte. In one or more illustrative examples, the solid polymer electrolyte can comprise polyethylene oxide. In one or more additional illustrative examples, the solid electrolyte can include a solid polymer electrolyte, one or both of which are Li + Li7La3Zr2O, which contributes to ionic conductivity 12 In one or more exemplary embodiments, the solid electrolyte may comprise a composite solid electrolyte including a polymer and an inorganic filler, such as polyethylene oxide mixed with Li. In one or more exemplary embodiments, the solid electrolyte may comprise a solid inorganic electrolyte. The solid inorganic electrolyte may comprise Li w La x M y O 12 (M is Nb, Ta, or Zr), Li x MP y S z (M is Ge or Sn), Li w Al x M y (PO4)3 (M is Ge or Ti), Li x Ti y M z (PO4)3 (where M is Cr, Ga, Fe, Sc, In, Lu, Y, or La), or Na x Zr2Si y PO 12where x, y, and z represent stoichiometric coefficients in all cases. In one or more further examples, the electrolyte may be composed of a solid polymer electrolyte. The solid polymer electrolyte may comprise one or more polymers of polyethylene oxide (PEO), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), poly(ethylene glycol) dimethacrylate (PEGDMA), or polyvinylpyrrolidone (PVP). Such polymers, when combined with a lithium salt such as LiClO4, LiPF6, or LiNO3, can yield a solid polymer electrolyte thin film. In one or more illustrative examples, the solid electrolyte may comprise a lithium-containing salt and an organic solvent. The organic solvent may comprise one or more molecules of ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane. Additionally, the organic solvent may comprise an ionic liquid, such as a salt containing a quaternary phosphorus or nitrogen cation, such as 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium. In one or more examples, the lithium-containing salt may comprise one or more of the following molecules: lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide.

[0100] In one or more examples, the surface of seed layer 728 may be further stabilized by applying a thin film nanolayer composed of a material different from the material of seed layer 728. Such a material may be described as an "artificial solid electrolyte interphase (SEI)." The artificial SEI serves to mitigate the formation of an electrochemically generated SEI during operation of any battery cell that includes seed layer 728. In various examples, the artificial SEI may be applied to the surface of seed layer 728 using a solution deposition method. In one or more illustrative examples, the artificial SEI may be applied to the surface of seed layer 728 according to one or more embodiments described in U.S. Patent Application No. 16 / 244,024, which is incorporated herein by reference in its entirety.

[0101] The second heat treatment process may differ from the first heat treatment process with respect to treatment conditions, such as the treatment environment and treatment temperature. In one or more additional examples, the second heat treatment process and the first heat treatment process may be performed under the same or similar conditions. In one or more examples, the fused nanoparticles 730 may include sintered interparticle bonds. In various examples, the fused nanoparticles 730 may be introduced using a non-convective heat treatment, such as laser sintering, microwave sintering, or light flash sintering. In various examples, the second chemical treatment process may differ from the second chemical treatment process. Furthermore, the second chemical treatment process and the first chemical treatment process may be performed under the same or similar conditions. In various examples, at least one of the second heat treatment process or the second chemical treatment process may be optional.

[0102] Further, in one or more examples, ligand-free nanoparticles may be applied to the current collector to help inhibit oxidation of the metal nanoparticles. In such cases, a metalorganic decomposition ink may be applied to the current collector. The ink may include a solvent. In one or more illustrative examples, the ink applied to the current collector may include a metalorganic ink. The ink may include at least one of a solvent or a porogen. In various examples, the ink may include one or more additives for stabilizing the ink. The ink may include metalorganic nanoparticles that are precursors used to form the nanostructured seed layer. In at least some examples, at least one of one or more thermal treatments or one or more chemical treatments may be applied to fuse the metalorganic precursors contained in the ink to the underlying current collector and itself to form the nanostructured seed layer. In various examples, the one or more thermal treatments may include a non-convective heat treatment technique, such as laser sintering, microwave sintering, or optical flash sintering. The one or more thermal treatments may be performed at a temperature of about 50°C to about 500°C for about 1 minute to about 6 hours. The one or more thermal treatments and / or the one or more chemical treatments may be performed in an inert atmosphere. The inert atmosphere may be performed in a reducing atmosphere containing an inert gas such as argon and / or nitrogen. The final product may include a metal nanoparticle film that serves as a seed layer for depositing a metal layer on a current collector substrate having a nanostructured seed layer. In this manner, fused nanoparticles 730 may be produced using a process different from that using ligand-functionalized nanoparticles.

[0103] FIG. 8 shows an exemplary process 800 for manufacturing a lithium metal coated substrate. Process 800 may include providing a substrate 802 including a current collector layer 708 and a seed layer 728 including fused nanoparticles 730. At 804, process 800 may include depositing lithium (Li) metal on substrate 802. Depositing Li metal on substrate 802 may produce a lithium metal coated substrate 806. Lithium metal coated substrate 806 may include fused nanoparticles 730 and a Li metal layer 808 disposed thereon. Deposition of Li metal on substrate 802 may be performed using an electrodeposition process. The electrodeposition process may be carried out in an electrodeposition bath. The electrodeposition bath may include an electrolyte, a lithium-containing salt, and a counter electrode. The electrolyte may include a lithium-containing salt and an organic solvent. The counter electrode may include lithium metal.

[0104] The organic solvent may comprise one or more molecules of ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane. Additionally, the organic solvent may comprise an ionic liquid, such as a salt containing a quaternary phosphorus or nitrogen cation, such as 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium. In one or more examples, the lithium-containing salt may comprise one or more molecules of lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide.

[0105] In one or more examples, the lithium metal layer 808 may be an initial pre-deposition layer. In various examples, the lithium metal may be electrodeposited onto the substrate 802 in a bath containing lithium metal or other suitable counter electrode and a lithium salt. The bath may also include one or more electrolytes, such as an ionic liquid. In one or more illustrative examples, a solid electrolyte interphase (SEI) 8710 may be formed on the Li metal layer 708. Advantages of performing a pre-deposition process may include the following: (a) Introducing a large amount of lithium metal into the substrate 802 prior to forming the battery cell can provide a "reservoir" of excess lithium to compensate for lithium consumed to form the SEI 810 (or due to other parasitic losses) during battery operation. (b) By pre-generating the SEI 810 on the pre-deposited Li metal layer 808, the formation of the SEI 810 can be eliminated to some extent during cell operation. In one or more embodiments, the pre-deposition process performed in operation 804 may be carried out using a roll-to-roll electrodeposition bath apparatus.

[0106] Process 800 may also include, in operation 812, forming a battery cell 814 including lithium metal coated substrate 806. In one or more examples, lithium metal coated substrate 806 may constitute an electrode of battery cell 814. In one or more illustrative examples, lithium metal coated substrate 806 may constitute an anode of battery cell 814. Battery cell 814 may be one of multiple battery cells included in a battery. The average thickness of lithium metal layer 808 when the battery is in a fully charged state ranges from 1 angstrom to 10,000 nm. In various examples, the average thickness of lithium metal layer 808 may increase upon charging of the battery relative to the initial thickness of lithium metal layer 808 on lithium metal coated substrate 806.

[0107] Batteries can be a power source used in a variety of implementations. For example, batteries can be a power source used in consumer electronic devices such as smartphones, laptop computing devices, wearable computing devices, tablet computing devices, handheld gaming consoles, and / or desktop computing devices. Furthermore, batteries can be a power source for electric vehicles. In one or more examples, batteries can also be a power source for other vehicles, such as aircraft and unmanned aerial vehicles. Batteries can also provide energy storage as part of a power grid that provides power to buildings, municipalities, and the like.

[0108] The battery cell 814 may include a housing 816. The housing 816 may be composed of one or more metallic materials. The housing 816 may also be composed of one or more polymeric materials. Multiple layers may be disposed within the housing 816. For example, one or more separator layers may be disposed within the housing 816. Additionally, one or more electrolyte layers may be disposed within the housing 816. Furthermore, multiple electrode layers may be disposed within the housing 816. For example, multiple anode layers and multiple cathode layers may be disposed within the housing 816.

[0109] In one or more exemplary embodiments, a first separator layer 818 may be disposed within the housing 816. Additionally, a first electrolyte layer 820 may be disposed within the housing 816. Additionally, a first electrode layer 822 may be disposed within the housing 816. In the illustrative example of FIG. 8 , the lithium metal coated substrate 806 may include a first electrode layer 822. In addition to the second separator layer 826, a second electrolyte layer 824 may be disposed within the housing 816. In various examples, the housing 816 may include a third electrolyte layer 828 and a second electrode layer 830. In one or more examples, the housing 816 may also include a fourth electrolyte layer 832. In one or more examples, the first electrode layer 822 may correspond to an anode layer, and the second electrode layer 830 may correspond to a cathode layer. In one or more additional examples, the first electrode layer 822 may correspond to a cathode layer, and the second electrode layer 830 may correspond to an anode layer. When the first electrode layer 822 comprises an anode layer, the second electrode layer 830 may comprise a LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiV2O5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients.

[0110] 8 shows an arrangement of layers of battery cell 814, additional embodiments may have a different number and arrangement of layers arranged within housing 816 of battery cell 814. Additionally, additional layers not shown in the illustrative example of FIG.

[0111] Below is a numbered, non-limiting list of aspects of the present subject matter.

[0112] Embodiment 1. A device comprising: a battery electrode comprising: a substrate having one or more polymeric materials; and a layer disposed on the substrate, wherein the layer comprises one or more conductive materials, has a thickness of 12 micrometers or less, and has a porosity measurement of at least 5% by volume.

[0113] Embodiment 2. The device of embodiment 1, wherein the one or more conductive materials include at least one of copper, aluminum, titanium, nickel, or stainless steel.

[0114] Embodiment 3. The device of embodiment 1 or 2, wherein the one or more polymeric materials have a glass transition temperature of 250° C. or less.

[0115] Embodiment 4. The device of any one of embodiments 1 to 3, wherein the one or more polymeric materials include at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyetheretherketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate.

[0116] Embodiment 5. The device of any one of embodiments 1 to 4, wherein the one or more conductive materials are formed as a multiplicity of particles having a spherical morphology.

[0117] Embodiment 6. The device of any one of embodiments 1 to 5, wherein the one or more conductive materials are formed as a multitude of particles having a nanowire morphology.

[0118] Embodiment 7. The device of any one of embodiments 1 to 6, wherein the layer comprises one or more electrode active materials.

[0119] Embodiment 8. The one or more electrode active materials correspond to the anode and include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO2, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co yAl z O2, LiMn x Ni y O z 8. The device of embodiment 7, comprising at least one of LiFePO, LiMnPO, LiNiPO, LiCoPO, LiV, O, sulfur, or LiCoO, wherein x, y, and z are stoichiometric coefficients.

[0120] Embodiment 9. The device of embodiment 7, wherein the layer comprises one or more binding materials for binding one or more electrode active materials with one or more conductive materials.

[0121] Embodiment 10. The device of embodiment 9, wherein the one or more binding materials comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate.

[0122] Embodiment 11. The device of embodiment 9 or 10, wherein the layer includes one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0123] Embodiment 12. The device of any one of embodiments 1 to 6, wherein the layer is a current collector layer, and the battery electrode includes an active material layer comprising one or more electrode active materials.

[0124] Embodiment 13. The one or more electrode active materials correspond to an anode and include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO2, Si, Sn, lithium metal, LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z, LiMnO 2 , LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , LiV 2 O 5 , sulfur, or LiCoO 2 , wherein x, y, and z are stoichiometric coefficients.

[0125] Embodiment 14. The device of embodiment 12, wherein the active material layer comprises one or more bonding materials for bonding the one or more electrode active materials with the one or more conductive materials.

[0126] Embodiment 15. The device of embodiment 14, wherein the one or more binding materials comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate.

[0127] Embodiment 16. The device of embodiment 14 or 15, wherein the active material layer includes one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0128] Embodiment 17. The device of any one of embodiments 1 to 16, wherein the substrate is formed into a first sheet and the layer disposed on the substrate is formed into a second sheet disposed on the first sheet.

[0129] Embodiment 18. The device of any one of embodiments 1 to 17, wherein the battery electrode is included in a lithium ion battery.

[0130] Embodiment 19. The device of any one of embodiments 1 to 18, wherein the layer comprises pores having diameters of 10 nanometers or less.

[0131] Embodiment 20. The device of any one of embodiments 1 to 19, wherein the substrate has a porosity of at least 5% by volume.

[0132] Embodiment 21. The device of any one of embodiments 1 to 20, wherein the thin encapsulating layer is formed over one or more conductive materials.

[0133] Embodiment 22. The device of any one of embodiments 1 to 21, wherein the layer comprises one or more flame retardant additives consisting of at least one of ammonium polyphosphate, ammonium sulfate, sodium borate, melamine, or pentaerythritol.

[0134] Embodiment 23. The device of any one of embodiments 1 to 22, wherein the layer comprises one or more first thermal management additives comprised of at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, or polyvinyl chloride.

[0135] Embodiment 24. The device of any one of embodiments 1 to 23, wherein the layer comprises one or more second thermal management additives comprised of at least one of ethylene vinyl acetate, polyvinyl alcohol, polycaprolactone, silicone, polyurethane, or naphthalene.

[0136] Aspect 25. A method comprising: preparing a substrate for a battery electrode, the substrate comprising one or more polymeric materials; and forming a layer on the substrate, the layer comprising one or more conductive materials, having a thickness of 12 micrometers or less, and having a porosity of at least 5% by volume.

[0137] Aspect 26. The method of aspect 25, wherein the step of forming a layer on the substrate comprises depositing an ink on the substrate.

[0138] Aspect 27. The method of aspect 26, comprising a step of subjecting the ink to one or more heat treatments after the ink has been deposited on the substrate, wherein the one or more heat treatments are carried out at a temperature of about 250°C or less.

[0139] Embodiment 28. The method of embodiment 27, wherein the one or more heat treatments are carried out in an environment comprising one or more gases including at least one of nitrogen, oxygen, hydrogen, or argon.

[0140] Embodiment 29. The method of embodiment 28, wherein the one or more gases are ionized.

[0141] Embodiment 30. The method of any one of embodiments 25 to 29, comprising performing a solution phase coating process to form the layer on the substrate.

[0142] Embodiment 31. The method of embodiment 30, wherein the solution phase coating process comprises at least one of a slot die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip coating process.

[0143] Embodiment 32. The method of any one of embodiments 26 to 31, wherein the ink comprises first particles composed of one or more conductive materials and one or more solvents.

[0144] Embodiment 33. The method of embodiment 32, wherein the one or more solvents comprise one or more organic solvents.

[0145] Embodiment 34. The method of embodiment 32 or 33, wherein the one or more solvents comprise at least one of isopropyl alcohol, ethanol, methanol, tert-butanol, 1-butanol, 2-amino-2-methyl-1-propanol, amino-2-propanol, 2-methoxyethanol, ethylene glycol, dipropylene glycol monomethyl ether, diethylene glycol methyl ether, benzyl alcohol, pyridine, tetrahydrofuran (THF), hexane, toluene, or water.

[0146] Embodiment 35. The method of any one of embodiments 32 to 34, wherein the ink comprises second particles comprising one or more electrode active materials.

[0147] Embodiment 36. The one or more electrode active materials correspond to an anode and include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO2, Si, Sn, lithium metal, LiNi xMn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiV2O5, sulfur, or LiCoO2, where x, y, and z are stoichiometric coefficients.

[0148] Embodiment 37. The method of embodiment 35 or 36, wherein the ink comprises one or more binding materials for binding the one or more electrode active materials with the one or more conductive materials.

[0149] Embodiment 38. The method of embodiment 37, wherein the one or more binding materials comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate.

[0150] Embodiment 39. The method of any one of embodiments 36 to 38, wherein the ink includes one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0151] Embodiment 40. The method of any one of embodiments 35 to 39, wherein the ink comprises one or more flame retardant additives consisting of at least one of ammonium polyphosphate, ammonium sulfate, sodium borate, melamine, or pentaerythritol.

[0152] Embodiment 41. The method of any one of embodiments 35 to 40, wherein the layer comprises one or more first thermal management additives comprised of at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, or polyvinyl chloride.

[0153] Embodiment 42. The method of any one of embodiments 35 to 41, wherein the layer comprises one or more second thermal management additives comprised of at least one of ethylene vinyl acetate, polyvinyl alcohol, polycaprolactone, silicone, polyurethane, or naphthalene.

[0154] Embodiment 43. The method of any one of embodiments 26 to 34, wherein the layer is a current collector, and the method includes forming an active material layer on the current collector layer, the active material layer comprising an active material of a battery electrode.

[0155] Embodiment 44. The method of embodiment 43, wherein the step of forming an active material layer on the current collector layer includes depositing additional ink on the current collector layer.

[0156] Aspect 45. The method of aspect 44, comprising a step of subjecting the additional ink to one or more additional heat treatments after the additional ink has been deposited on the current collector, wherein the one or more additional heat treatments are performed at a temperature of about 250°C or less.

[0157] Embodiment 46. The method of embodiment 45, wherein the one or more additional heat treatments are performed in an environment containing one or more gases including at least one of nitrogen, oxygen, hydrogen, ozone, or argon.

[0158] Embodiment 47. The method of embodiment 46, wherein the one or more gases are ionized.

[0159] Embodiment 48. The method of embodiment 43-47, comprising performing an additional solution phase coating process to form an active material layer on the current collector layer.

[0160] Embodiment 49. The method of embodiment 48, wherein the additional solution phase coating process comprises at least one of a slot die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip coating process.

[0161] Aspect 50. A method described in any one of aspects 25 to 49, comprising a step of performing one or more pretreatment processes on the substrate before forming a layer on the substrate, wherein the one or more pretreatment processes include at least one of ultraviolet light, ozone, corona discharge, atmospheric pressure plasma, or applying one or more chemical solutions to the substrate.

[0162] Aspect 51. A method according to any one of aspects 25 to 50, comprising a step of subjecting at least one of the one or more conductive materials or one or more conductive material-active electrode material composites disposed on the substrate to one or more heat treatments, wherein the one or more heat treatments comprise at least one of light flash sintering, spark plasma sintering, ultrasonic sintering, or microwave sintering.

[0163] Embodiment 52. A formulation comprising one or more solvents, first particles comprised of one or more conductive materials, and second particles comprised of one or more electrode active materials.

[0164] Embodiment 53. The formulation of embodiment 52, wherein the one or more conductive materials include at least one of copper, aluminum, titanium, nickel, or stainless steel.

[0165] Embodiment 54. The formulation of embodiment 52 or 53, wherein the one or more solvents comprise at least one of isopropyl alcohol, ethanol, methanol, tert-butanol, 1-butanol, 2-amino-2-methyl-1-propanol, amino-2-propanol, 2-methoxyethanol, ethylene glycol, dipropylene glycol monomethyl ether, diethylene glycol methyl ether, benzyl alcohol, pyridine, tetrahydrofuran (THF), hexane, toluene, or water.

[0166] Embodiment 55. The one or more electrode active materials correspond to an anode and include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO2, Si, Sn, lithium metal, LiNi x Mn yCo z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiV2O5, sulfur, or LiCoO2, and x, y, and z are stoichiometric coefficients.

[0167] Embodiment 56. The formulation of any one of embodiments 52 to 55, comprising third particles comprising one or more binding materials for binding the one or more electrode active materials with the one or more conductive materials.

[0168] Embodiment 57. The formulation of embodiment 56, wherein the one or more bonding materials include at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, poly(acrylic acid), poly(methyl methacrylate), polyvinyl alcohol, or polypropylene carbonate.

[0169] Embodiment 58. The formulation of any one of embodiments 52 to 57, comprising fourth particles comprising one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles.

[0170] Embodiment 59. The formulation of any one of embodiments 52 to 58, comprising an ink having first particles and second particles.

[0171] Embodiment 60. The formulation of any one of embodiments 52 to 59, comprising one or more flame retardant additives consisting of at least one of ammonium polyphosphate, ammonium sulfate, sodium borate, melamine, or pentaerythritol.

[0172] Embodiment 61. The formulation of any one of embodiments 52 to 60, comprising one or more first thermal management additives comprised of at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, or polyvinyl chloride.

[0173] Embodiment 62. The formulation of any one of embodiments 52 to 61, comprising one or more second thermal management additives comprised of at least one of ethylene vinyl acetate, polyvinyl alcohol, polycaprolactone, silicone, polyurethane, or naphthalene.

[0174] Embodiment 63. A method for producing a substrate comprising a nanostructured seed layer on one or more surfaces of a current collector, the method may include: preparing an ink comprising a solution comprising at least ligand-functionalized nanoparticles and a solvent; applying a thin wet film of the ink to a current collector using a solution-phase thin film coating process; drying the thin wet film to produce a thin dry film of the ligand-functionalized nanoparticles, wherein the current collector comprises one or more polymeric materials; and performing one or more thermal and / or chemical treatments on the thin dry film, thereby producing a substrate comprising a free-standing porous nanostructured seed layer on one or more surfaces of the current collector.

[0175] Embodiment 64. The method of embodiment 63, wherein the nanoparticles are composed of a metal.

[0176] 65. Metal is 1x10 -12 65. The method of embodiment 64, wherein the bulk resistivity is between ohm-cm and 1 ohm-cm.

[0177] Embodiment 66. The method of any one of embodiments 63 to 65, wherein the nanoparticles are composed of a semiconductor.

[0178] Embodiment 67. The method of embodiment 66, wherein the semiconductor has a bulk resistivity of 1 ohm-cm to 1000 ohm-cm.

[0179] Embodiment 68. The method of any one of embodiments 63 to 67, wherein the nanoparticles are composed of an insulator.

[0180] 69. The insulator has a resistance of 1000 ohm-cm to 1x10 13 69. The method of embodiment 68, having a bulk resistivity of ohm-cm.

[0181] Embodiment 70. The method of any one of embodiments 63 to 69, wherein the nanoparticles have a spherical shape.

[0182] Embodiment 71 The method of any one of embodiments 63 to 70, wherein the nanoparticles have a multifaceted polyhedral shape.

[0183] Embodiment 72. The method of embodiment 71, wherein the nanoparticles have a diameter of 1 angstrom to 100 nm.

[0184] Embodiment 73. The method of embodiment 72, wherein any dimension of the polyhedral shape of the nanoparticle has a length between 1 angstrom and 100 nm.

[0185] Embodiment 74. The method of any one of embodiments 63 to 73, wherein the ligand is a molecule comprising a chelating group that coordinates to the surface of the nanoparticle and a solubilizing group that allows the nanoparticle to be dispersed in a solvent.

[0186] Embodiment 75. The method of any one of embodiments 63 to 74, comprising adding an organic molecule to the ink in step (a).

[0187] Embodiment 76. The method of any one of embodiments 63 to 75, wherein the dried film in step (c) is subjected to one or more heat treatments in a temperature range of 30 to 650°C.

[0188] Embodiment 77. The method of embodiment 76, wherein the one or more heat treatments are carried out in an ambient atmosphere containing a gas composed of nitrogen, oxygen, hydrogen, argon, or a combination thereof.

[0189] Embodiment 78. The method of embodiment 77, wherein the one or more gases are ionized.

[0190] Embodiment 79. The method of any one of embodiments 63 to 78, wherein the solution phase coating process is a slot die, spray, aerosol, bath, gravure, comma, or dip coating process.

[0191] Embodiment 80. The method of any one of embodiments 63 to 79, wherein the ink further comprises a rheology modifier or a porosity modifier.

[0192] Embodiment 81. The method of any one of embodiments 63 to 80, wherein the porosity of the nanostructured seed layer ranges from 1% to 99%.

[0193] Embodiment 82. The method of any one of embodiments 63 to 81, wherein the one or more chemical treatments include exposing the substrate to a bath containing a solution comprising residual cleaning solvent and at least one chemical reagent.

[0194] Embodiment 83. The method of embodiment 82, wherein the bath is heated to a temperature of 30°C to 300°C.

[0195] Embodiment 84. The method of embodiment 82, wherein the solution removes residual organic molecules in the nanostructure seed layer via a dissolution or depolymerization mechanism.

[0196] Embodiment 85. The method of any one of embodiments 63 to 84, wherein at least some of the pores of the nanostructured seed layer are backfilled with a solid electrolyte.

[0197] Embodiment 86. The method of embodiment 85, wherein the solid electrolyte comprises a solid polymer electrolyte.

[0198] Embodiment 87. The method of embodiment 86, wherein the solid polymer electrolyte comprises polyethylene oxide.

[0199] Embodiment 88. The method of embodiment 86, wherein the solid polymer electrolyte comprises one or more polymers of polyethylene oxide (PEO), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), poly(ethylene glycol) dimethacrylate (PEGDMA), or polyvinylpyrrolidone (PVP).

[0200] Embodiment 89. The method of embodiment 85, wherein the solid electrolyte comprises a composite solid electrolyte comprising a polymer and an inorganic filler.

[0201] Embodiment 90. At least one of the polymer or inorganic filler is Li + 90. The method of embodiment 89, wherein the method contributes to ionic conduction.

[0202] Aspect 91. The solid electrolyte is Li7La3Zr2O 12 86. The method of embodiment 85, comprising mixing polyethylene oxide.

[0203] Embodiment 92. The method of embodiment 85, wherein the solid electrolyte comprises a solid inorganic electrolyte.

[0204] Aspect 93. The solid inorganic electrolyte is Li w La x M y O 12 (M is Nb, Ta, or Zr), Li x MP y S z (M is Ge or Sn), Li w Al x M y (PO4)3 (M is Ge or Ti), Li x Ti y M z (PO4)3 (where M is Cr, Ga, Fe, Sc, In, Lu, Y, or La), or Na x Zr2Si y PO 12 93. The method of embodiment 92, comprising one or more of:

[0205] Embodiment 94. The method of embodiment 85, wherein the solid electrolyte comprises a lithium-containing salt and an organic solvent.

[0206] Embodiment 95. The method of embodiment 94, wherein the organic solvent comprises at least one of ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane.

[0207] Aspect 96. The method of aspect 94, wherein the organic solvent comprises an ionic liquid.

[0208] Embodiment 97. The method of embodiment 96, wherein the ionic liquid comprises a quaternary phosphorus or nitrogen cation.

[0209] Embodiment 98. The method of embodiment 97, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium.

[0210] Embodiment 99. The method of embodiment 95, wherein the lithium-containing salt comprises at least one of lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide.

[0211] Embodiment 100. The method of any one of embodiments 63 to 99, wherein the current collector comprises a foil.

[0212] Embodiment 101. The method of any one of embodiments 63 to 100, wherein the nanostructured seed layer is made conductive by electroless plating with one or more metals.

[0213] Embodiment 102. The method of any one of embodiments 63 to 101, wherein the non-convective heat treatment is performed in addition to or instead of a thermal or chemical treatment.

[0214] Aspect 103. The method of aspect 102, wherein the non-convective heat treatment comprises laser sintering, microwave sintering, or light flash sintering.

[0215] Embodiment 104. The method of any one of embodiments 63 to 103, wherein the seed layer is composed of at least two different types of nanoparticles, and the at least two different nanoparticles are composed of different materials.

[0216] Embodiment 105. The method of any one of embodiments 63 to 104, wherein the seed layer is composed of core-shell nanoparticles, the core being composed of one material and the shell being composed of a different material.

[0217] Embodiment 106. The method of any one of embodiments 63 to 105, comprising forming an artificial solid electrolyte interfacial layer on at least a portion of the seed layer.

[0218] Embodiment 107. The method of embodiment 106, wherein the artificial solid electrolyte interfacial layer comprises one or more monolayers.

[0219] Embodiment 108. The method of embodiment 106 or 107, wherein the artificial solid electrolyte interface layer comprises a metallic material.

[0220] Embodiment 109. The method of any one of embodiments 106 to 108, wherein the artificial solid electrolyte interface layer comprises a polymer material.

[0221] Embodiment 110. The method of any one of embodiments 63 to 109, wherein the one or more polymeric materials comprise at least one of polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate.

[0222] Embodiment 111. The method of any one of embodiments 63 to 110, wherein the one or more polymeric materials comprise one or more metals.

[0223] Embodiment 112. The method of embodiment 111, wherein the one or more metals comprise at least one of copper, titanium, nickel, or stainless steel.

[0224] Embodiment 113. The method of any one of embodiments 63 to 110, wherein the current collector is composed entirely of one or more polymeric materials.

[0225] Embodiment 114. The method of any one of embodiments 63 to 113, wherein the nanostructured seed layer deposited on the current collector is electrically conductive.

[0226] Embodiment 115. A method for producing a lithium metal coated substrate, comprising: providing a substrate comprising a nanoparticle seed layer on one or more surfaces of a current collector; and electrodepositing lithium onto the nanoparticle seed layer of the substrate to form the lithium metal coated substrate.

[0227] Embodiment 116. The method of embodiment 115, wherein the substrate comprising a nanoparticle seed layer on one or more surfaces of a current collector is produced by the method of any of embodiments 63 to 114.

[0228] Embodiment 117. The method of embodiment 115, wherein the electrodeposition occurs in an electrodeposition bath comprising an electrolyte, a lithium-containing salt, and a counter electrode.

[0229] Embodiment 118. The method of embodiment 117, wherein the electrolyte is composed of a lithium-containing salt and an organic solvent.

[0230] Embodiment 119. The method of embodiment 118, wherein the organic solvent comprises one or more of the following molecules: ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane.

[0231] Embodiment 120. The method of embodiment 118 or 119, wherein the lithium-containing salt comprises one or more of a molecule of lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide.

[0232] Embodiment 121. The method of embodiment 118, wherein the organic solvent comprises an ionic liquid, such as a salt containing a quaternary phosphorus or nitrogen cation, such as 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium.

[0233] Embodiment 122. The method of embodiment 115, wherein the method is performed before assembling the lithium metal-coated substrate with a cathode, an electrolyte, a separator, and a housing to form a battery.

[0234] Embodiment 123. The method of embodiment 122, wherein the average thickness of the lithium metal on the nanostructured seed layer when the battery is in a fully charged state is in the range of 1 Angstrom to 1000 nm.

[0235] Aspect 124. The cathode is LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO2, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, LiV2O5, sulfur, or LiCoO2, and x, y, and z are stoichiometric coefficients.

[0236] Embodiment 125. The method of any one of embodiments 115 to 124, wherein the nanoparticle seed layer is produced according to the method of any one of embodiments 63 to 114.

[0237] Embodiment 126. A battery comprising a lithium metal-coated substrate manufactured by the method of any one of embodiments 63 to 114.

[0238] Embodiment 127. The battery of embodiment 126, wherein the average thickness of the lithium metal on the nanostructured seed layer when the battery is in a fully charged state is in the range of 1 Angstrom to 1000 nm.

[0239] Embodiment 128. The cathode further comprises LiNi x Mn y Co z O2, LiNi x Co y Al z O2, LiMn x Ni y O z , LiMnO 2 , LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , LiV 2 O 5 , sulfur, or LiCoO 2 , and x, y, and z are stoichiometric coefficients.

[0240] Embodiment 129. A substrate comprising a nanostructured seed layer on one or more surfaces of a current collector.

[0241] Embodiment 130. The substrate of embodiment 129, produced by the method of any one of embodiments 63 to 114.

[0242] Embodiment 131. A battery comprising: a housing; and one or more battery cells disposed within the housing, each of the one or more battery cells comprising: (i) an electrode layer including a seed layer composed of a multitude of fused nanoparticles; and (ii) a lithium metal layer disposed on the multitude of fused nanoparticles; one or more separator layers; and one or more electrolyte layers including an electrolyte.

[0243] Embodiment 132. The substrate of embodiment 131, wherein the seed layer comprises a plurality of pores, at least a portion of which are filled with additional electrolyte.

[0244] Embodiment 133. The battery of embodiment 132, wherein the additional electrolyte is composed of a lithium-containing salt and an organic solvent.

[0245] Embodiment 134. The battery of embodiment 132, wherein the organic solvent comprises one or more of the following molecules: ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane.

[0246] Embodiment 135. The battery of embodiment 132, wherein the lithium-containing salt comprises one or more of a lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide molecule.

[0247] Embodiment 136. The battery of embodiment 132, wherein the organic solvent comprises an ionic liquid.

[0248] Embodiment 137. The battery of embodiment 136, wherein the ionic liquid comprises a quaternary phosphorus or nitrogen cation.

[0249] Embodiment 138. The battery of embodiment 137, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium.

[0250] Aspect 139. The additional solid inorganic electrolyte is Li w La x M y O 12 (M is Nb, Ta, or Zr), Li x MP y S z (M is Ge or Sn), Li w Al x M y (PO4)3 (M is Ge or Ti), Li x Ti y M z(PO4)3 (where M is Cr, Ga, Fe, Sc, In, Lu, Y, or La), or Na x Zr2Si y PO 12 wherein x, y, and z represent stoichiometric coefficients.

[0251] Embodiment 140. The battery of embodiment 132, wherein the additional solid polymer electrolyte is composed of one or more polymers of polyethylene oxide (PEO), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), poly(ethylene glycol) dimethacrylate (PEGDMA), or polyvinylpyrrolidone (PVP). Such polymers, when combined with a lithium salt, such as LiClO4, LiPF6, or LiNO3, can provide a solid polymer electrolyte thin film.

[0252] Embodiment 141. The battery of embodiment 132, wherein the additional solid electrolyte comprises a composite solid electrolyte comprising a polymer and an inorganic filler.

[0253] Embodiment 142. At least one of the polymer or inorganic filler is Li + 142. The battery of embodiment 141, wherein the battery contributes to ionic conduction.

[0254] Aspect 143. The additional solid electrolyte is Li7La3Zr2O 12 134. The battery of embodiment 133, comprising a polyethylene oxide mixed therewith.

[0255] Embodiment 144. A formulation comprising: a solvent; a plurality of nanoparticles disposed in the solvent, wherein the plurality of nanoparticles have one or more dimensions from about 0.5 nanometers to about 500 nanometers; and one or more ligands attached to individual nanoparticles of the plurality of nanoparticles, wherein the one or more ligands have a molecular weight from 20 Daltons (Da) to 10 kDa.

[0256] Embodiment 145. The formulation of embodiment 144, wherein the one or more ligands functionalize the surface of at least a portion of the plurality of nanoparticles.

[0257] Embodiment 146. The formulation of embodiment 144 or 145, wherein the one or more ligands comprise an ionically conductive material.

[0258] Embodiment 147. The combination according to any one of embodiments 144 to 146, wherein the one or more ligands comprise a molecule having a chelating group.

[0259] Embodiment 148. The formulation of any one of embodiments 144 to 147, wherein at least a portion of the plurality of nanoparticles is composed of one or more metallic materials.

[0260] Embodiment 149. The formulation of any one of embodiments 144 to 148, wherein at least a portion of the plurality of nanoparticles is composed of one or more semiconductor materials.

[0261] Embodiment 150. The formulation of embodiments 144 to 147, wherein at least a portion of the plurality of nanoparticles are composed of one or more insulating materials.

[0262] Embodiment 151. The formulation of any one of embodiments 144 to 150, wherein the plurality of nanoparticles avoids introducing excessive DC resistance during operation of a battery comprising the plurality of nanoparticles.

[0263] Embodiment 152. The formulation of embodiments 144 to 151, wherein the plurality of nanoparticles comprises a first plurality of nanoparticles having a first composition and a second plurality of nanoparticles having a second composition.

[0264] Embodiment 153. The formulation of embodiment 152, wherein at least a portion of the plurality of nanoparticles have a core-shell shape having an inner core comprised of one or more first materials and an outer shell disposed around the inner core comprised of one or more second materials.

[0265] Embodiment 154. The formulation of any one of embodiments 144 to 153, comprising one or more additives.

[0266] Embodiment 155. The formulation of embodiment 154, wherein the one or more additives include one or more rheology modifiers or one or more porosity modifiers.

[0267] Embodiment 156. The formulation of any one of embodiments 144 to 155, wherein the solids content is about 1% to 90%, and the solids content is a ratio of the mass of the plurality of nanoparticles and the mass of the one or more ligands to the mass of the solvent.

[0268] Embodiment 157. The formulation of any one of embodiments 144 to 156, wherein the formulation is characterized as an ink.

[0269] Embodiment 158. A method for producing a substrate comprising a nanostructured seed layer on one or more surfaces of a current collector, the method comprising: preparing an ink comprising a solution comprising at least one or more molecular precursors and a solvent; depositing a thin wet film of the ink that can be applied to a current collector, the current collector comprising one or more polymeric materials; and performing at least one of one or more thermal treatments or one or more chemical treatments on the thin wet film to produce a substrate comprising a free-standing porous nanostructured seed layer on one or more surfaces of the current collector.

[0270] Embodiment 159. The method of embodiment 158, wherein the one or more molecular precursors comprise one or more organometallic nanoparticles.

[0271] Embodiment 160. The method of embodiment 159, wherein the ink is applied to the current collector using a solution-phase thin film coating process.

[0272] Embodiment 161. The method of any one of embodiments 158 to 160, wherein at least some of the pores of the nanostructured seed layer are backfilled with a solid electrolyte.

[0273] Embodiment 162. The method of embodiment 161, wherein the solid electrolyte comprises a solid polymer electrolyte.

[0274] Embodiment 163. The method of embodiment 162, wherein the solid polymer electrolyte comprises polyethylene oxide.

[0275] Embodiment 164. The method of embodiment 162, wherein the solid polymer electrolyte comprises one or more polymers of polyethylene oxide (PEO), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), poly(ethylene glycol) dimethacrylate (PEGDMA), or polyvinylpyrrolidone (PVP).

[0276] Embodiment 165. The method of embodiment 161, wherein the solid electrolyte comprises a composite solid electrolyte comprising a polymer and an inorganic filler.

[0277] Embodiment 166. At least one of the polymer or inorganic filler is Li + 166. The method of embodiment 165, wherein the method contributes to ionic conduction.

[0278] Aspect 167. The solid electrolyte is Li7La3Zr2O 12 162. The method of embodiment 161, comprising mixing polyethylene oxide.

[0279] Embodiment 168. The method of embodiment 161, wherein the solid electrolyte comprises a solid inorganic electrolyte.

[0280] 169. The solid inorganic electrolyte is Li w La x M y O 12 (M is Nb, Ta, or Zr), Li x MP y S z (M is Ge or Sn), Li w Al x M y (PO4)3 (M is Ge or Ti), Li x Ti y M z (PO4)3 (where M is Cr, Ga, Fe, Sc, In, Lu, Y, or La), or Na x Zr2Si y PO 12169. The method of embodiment 168, comprising one or more of:

[0281] Embodiment 170. The method of embodiment 161, wherein the solid electrolyte comprises a lithium-containing salt and an organic solvent.

[0282] Embodiment 171. The method of embodiment 170, wherein the organic solvent comprises at least one of ethylene carbonate, ethyl methyl carbonate, propylene carbonate, glyme, diglyme, dioxolane, vinylene carbonate, propane sultone, diethyl carbonate, dimethyl carbonate, or sulfolane.

[0283] Embodiment 172. The method of embodiment 170, wherein the organic solvent comprises an ionic liquid.

[0284] Embodiment 173. The method of embodiment 172, wherein the ionic liquid comprises a quaternary phosphorus or nitrogen cation.

[0285] Embodiment 174. The method of embodiment 173, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium or 1-butyl-1-methylpyrrolidinium.

[0286] Embodiment 175. The method of embodiment 170, wherein the lithium-containing salt comprises at least one of lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), or lithium bis(fluorosulfonyl)imide.

[0287] Embodiment 176. The method of any one of embodiments 158 to 175, wherein the current collector comprises a foil.

[0288] Embodiment 177. The method of any one of embodiments 158 to 176, wherein the nanostructure seed layer is made conductive by electroless plating with one or more metals.

[0289] Embodiment 178. The method of any one of embodiments 158 to 177, wherein the non-convective heat treatment is performed in addition to or instead of the thermal or chemical treatment.

[0290] Aspect 179. The method of aspect 178, wherein the non-convective heat treatment comprises laser sintering, microwave sintering, or light flash sintering.

[0291] Embodiment 180. The method of any one of embodiments 158 to 179, wherein the seed layer is composed of at least two different types of nanoparticles, and the at least two different nanoparticles are composed of different materials.

[0292] Embodiment 181. The method of any one of embodiments 158 to 179, wherein the seed layer is composed of core-shell nanoparticles, the core being composed of one material and the shell being composed of a different material.

[0293] Embodiment 182. The method of any one of embodiments 158 to 181, comprising forming an artificial solid electrolyte interfacial layer on at least a portion of the seed layer.

[0294] Embodiment 183. The method of embodiment 182, wherein the artificial solid electrolyte interfacial layer comprises one or more monolayers.

[0295] Embodiment 184. The method of embodiment 182 or 183, wherein the artificial solid electrolyte interface layer comprises a metallic material.

[0296] Embodiment 185. The method of any one of embodiments 182 to 184, wherein the artificial solid electrolyte interface layer comprises a polymer material.

[0297] Embodiment 186. The method of any one of embodiments 158 to 185, wherein the ink comprises a metal organic precursor.

[0298] Embodiment 187. The method of embodiment 159, wherein the one or more nanoparticles are composed of a metal.

[0299] Aspect 188. Metal is 1x10-12 188. The method of embodiment 187, wherein the bulk resistivity is between ohm-cm and 1 ohm-cm.

[0300] Embodiment 189. The method of embodiment 159, wherein the one or more nanoparticles are composed of a semiconductor.

[0301] Embodiment 190. The method of embodiment 189, wherein the semiconductor has a bulk resistivity of 1 ohm-cm to 1000 ohm-cm.

[0302] Embodiment 191. The method of embodiment 159, wherein the one or more nanoparticles are composed of an insulator.

[0303] Aspect 192. The insulator has a resistance of 1000 ohm-cm to 1x10 13 192. The method of embodiment 191, having a bulk resistivity of ohm-cm.

[0304] Embodiment 193. The method of any one of embodiments 159 to 192, wherein the one or more nanoparticles have a spherical shape.

[0305] Embodiment 194. The method of any one of embodiments 159 to 193, wherein the one or more nanoparticles have a multifaceted polyhedral shape.

[0306] Embodiment 195. The method of embodiment 194, wherein the one or more nanoparticles have a diameter between 1 angstrom and 100 nm.

[0307] Embodiment 196. The method of embodiment 195, wherein any dimension of the polyhedral shape of the nanoparticle has a length between 1 angstrom and 100 nm.

[0308] Embodiment 197. The method of any one of embodiments 158 to 196, comprising adding an organic molecule to the ink.

[0309] Embodiment 198. The method of any one of embodiments 158 to 197, wherein the dried film is subjected to one or more heat treatments in the temperature range of 30 to 650°C.

[0310] Embodiment 199. The method of embodiment 198, wherein the one or more heat treatments are carried out in an ambient atmosphere containing a gas composed of nitrogen, oxygen, hydrogen, argon, or a combination thereof.

[0311] Embodiment 200. The method of embodiment 199, wherein the one or more gases are ionized.

[0312] Embodiment 201. The method of any one of embodiments 158 to 200, wherein the solution phase coating process is a slot die, spray, aerosol, bath, gravure, comma, or dip coating process.

[0313] Embodiment 202. The method of any one of embodiments 158 to 201, wherein the ink further comprises a rheology modifier or a porosity modifier.

[0314] Embodiment 203. The method of any one of embodiments 158 to 202, wherein the porosity of the nanostructured seed layer ranges from 1% to 99%.

[0315] Embodiment 204. The method of any one of embodiments 158 to 203, wherein the one or more chemical treatments include exposing the substrate to a bath containing a solution comprising residual cleaning solvent and at least one chemical reagent.

[0316] Embodiment 205. The method of embodiment 204, wherein the bath is heated to a temperature of 30°C to 300°C.

[0317] Embodiment 206. The method of embodiment 205, wherein the solution removes residual organic molecules in the nanostructure seed layer via a dissolution or depolymerization mechanism.

[0318] Embodiment 207. The method of any one of embodiments 158 to 206, wherein the one or more polymeric materials comprise at least one of polyethylene, polypropylene, polyimide, polyetheretherketone, polyester, polyamide, or polyethylene naphthalate.

[0319] Embodiment 208. The method of any one of embodiments 158 to 207, wherein the one or more polymeric materials comprise one or more metals.

[0320] Embodiment 209. The method of embodiment 208, wherein the one or more metals comprise at least one of copper, titanium, nickel, or stainless steel.

[0321] Embodiment 210. The method of any one of embodiments 158 to 207, wherein the current collector is composed entirely of one or more polymeric materials.

[0322] Embodiment 211. The method of any one of embodiments 158 to 210, wherein the nanostructured seed layer deposited on the current collector is electrically conductive. [Example]

[0323] To illustrate the effectiveness of the nanoparticle seed layer, the following example is provided. (a) Nanoparticles of 2 nm diameter comprising spherical metallic materials are functionalized with suitable ligands and dispersed in a suitable solvent such as THF along with pore-generating and rheology-modifying additives to form a nanoparticle ink. (b) The ink is cast onto a foil current collector and the residual solvent is allowed to evaporate at room temperature, leaving a “dry” film of ligand-functionalized nanoparticles. (c) Successive thermal treatments, with or without chemical treatments such as ligand dissolution, are performed to convert the "dried" film into a free-standing nanoparticle matrix "seed layer" composed of necked nanoparticles remaining on top of the foil current collector. The ligands, additives, ink rheology, and other ink design parameters are selected so that the final seed layer, after all thermal and chemical treatments, is composed of approximately 30% by volume nanoparticles and approximately 70% by volume open space (porosity). The effective thickness (including porosity) of the seed layer at this composition is approximately 32 μm. 1 cm of planar foil of the seed layer 2 The total pore volume per -9 m 3 1cm of flat foil 2 The effective volume occupied by the seed layer (including porosity) per-9 m 3 is. (d) A “pre-deposition” process is then performed on the seed layer and current collector (collectively “substrate”) to uniformly deposit an approximately 0.5 Å thick Li metal layer on the nanoparticle surface from an electrodeposition bath comprising a combination of Li metal, Li salt, and electrolyte. (e) Next, the substrate is heated to a temperature of 3 mAh / cm 2 The seed layer is then combined with a cathode, a suitable electrolyte, a separator, and a housing to create a battery cell, in which the substrate acts as the negative electrode. Upon assembly, the electrolyte fills the pores in the seed layer, creating diffusion paths for Li-ions throughout the seed layer. (f) Cell is 3mAh / cm 2 At this charge state, the thickness of the lithium metal layer on all nanoparticle surfaces increases from 0.5 Å to 4.5 Å. (g) The effective volume of lithium metal added to the nanoparticle surface is 1 cm of planar foil area. 2 Approximately 1.6x10 -9 m 3 , which is the available pore volume in the structure of 2.2x10 -9 m 3 / cm 2 This allows for ample space for the lithium metal to occupy. The residual porosity after Li deposition is 2 Approximately 0.6x10 per -9 m 3 This corresponds to about 19% of the total volume occupied by the seed layer. The porosity of the final thin film can be determined by techniques such as the Brunauer-Emmett-Teller (BET) theory. This is slightly lower than the porosity of state-of-the-art graphite anodes (about 25%). This residual volume is thought to be occupied by the electrolyte and SEI.

[0324] In the above example, by limiting the growth of the lithium metal layer to the range of 0.5 Å to 4.5 Å, the pre-formed SEI is not subjected to excessive mechanical stress and is therefore more likely to remain intact. For example, typical 1-10 micron graphite particles used in state-of-the-art LIB anodes expand by tens to hundreds of nanometers during lithiation, with little or no adverse effect on the SEI.

[0325] In the above example, the spherical nanoparticles can be replaced with nanoparticles of different shapes, such as faceted polyhedra or nanorods with high aspect ratios. Other faceted polyhedra (e.g., tetrahedra) are known to have higher surface area-to-volume ratios than spheres. Furthermore, by appropriately tailoring the shape of the nanoparticles, optimized seed layer structures can be achieved to achieve high porosity, high surface area-to-seed layer volume, and high mechanical strength.

[0326] In the above example, the resulting thickness occupied by the nanoparticle seed layer (i.e., including the porosity) is approximately 32 microns, which is approximately twice the minimum thickness that the same amount of lithium in the above example could theoretically occupy if deposited as a continuous film at bulk density. However, as noted above, a Li metal film electrodeposited on a planar current collector during practical battery operation will have a much lower bulk density than the Li metal due to its non-uniform dendritic structure. Furthermore, a 32 micron thick anode layer will have a capacity of 3 mAh / cm. 2 This represents a significant improvement in volumetric capacity compared to comparable state-of-the-art graphite layers combined with cathodes, such graphite layers typically exceeding 80 microns in thickness.

[0327] In the above example, the nanoparticles are "monodisperse," i.e., they all have a diameter of 2 nm. In another embodiment, the nanoparticles are "polydisperse," i.e., they have a range of diameters. In yet another embodiment, the nanoparticles are polydisperse and not spherical, spanning a range of dimensions specific to the shape of the nanoparticles. Such polydispersity may further optimize the seed layer for high porosity, high surface area relative to the total volume of the seed layer, and high mechanical strength.

[0328] In one or more additional embodiments, to tailor the microstructure and porosity of the seed layer, nanoparticles of various sizes are applied in multiple sequential layers instead of a single layer. In such embodiments, some layers may be composed of larger nanoparticles and some layers may be composed of smaller nanoparticles. For example, the smaller nanoparticles may have a size distribution with a D50 of 1 nm, while the larger nanoparticles may have a size distribution with a D50 of 5 nm.

[0329] In one or more instances, the structure of the nanoparticle seed layer may be such that it leaves enough porosity for lithium metal growth, but insufficient space to support high liquid electrolyte penetration coupled with high levels of SEI growth. However, it is known that in state-of-the-art graphite anodes, a few nanometers of SEI grown on the graphite surface barely increases the cell impedance. Thus, even if the majority of the porosity in the nanoparticle seed layer is occupied by the SEI, the diffusion of Li ions through the SEI is sufficiently high that it does not necessarily adversely affect the cell's power performance.

[0330] In various examples, the nanoparticle seed layer can be filled with a certain amount of solid polymer electrolyte, such as polyethylene oxide (PEO), to enhance ionic conductivity. In one or more embodiments, the solid polymer electrolyte maintains high ionic conductivity within the pores of the seed layer while preventing excessive SEI growth, which often occurs with liquid electrolytes. Furthermore, the solid polymer electrolyte has sufficient elasticity to easily accommodate the growth of a 0.5-4.5 angstrom Li metal layer, as in the example above. The solid polymer electrolyte filled within the nanoparticle seed layer can improve the mechanical strength of the seed layer and also function as a physical barrier against atmospheric contaminants. For example, if the nanoparticle seed layer is composed of a metal that is easily oxidized in the atmosphere, the solid polymer electrolyte layer can function as a physical protective barrier against oxidation, which can reduce the electrical conductivity of the seed layer. In various examples, the filled solid electrolyte can be composed of a solid inorganic electrolyte. The solid inorganic electrolyte can be Liw La x M y O 12 (M is Nb, Ta, or Zr), Li x MP y S z (M is Ge or Sn), Li w Al x M y (PO4)3 (M is Ge or Ti), Li x Ti y M z (PO4)3 (where M is Cr, Ga, Fe, Sc, In, Lu, Y, or La), or Na x Zr2Si y PO 12 where x, y, and z represent stoichiometric coefficients. In various examples, the filled solid electrolyte may be composed of a solid polymer electrolyte. The solid polymer electrolyte may comprise one or more polymers of polyethylene oxide (PEO), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), poly(ethylene glycol) dimethacrylate (PEGDMA), or polyvinylpyrrolidone (PVP). Such polymers, when combined with lithium salts such as LiClO4, LiPF6, or LiNO3, can yield solid polymer electrolyte thin films.

[0331] While specific configurations have been described, the configurations described herein are intended in all respects to be possible configurations, not limiting, and therefore the scope is not limited to the specific configurations described. Unless otherwise expressly stated, methods described herein are not intended to be construed as requiring that their steps be performed in a particular order. Thus, where a method claim does not actually recite the order in which its steps are to be performed, or where the claim or specification does not specifically state that the steps are limited to a particular order, no order is intended to be inferred in any respect. This also applies to any implicit basis for interpretation, such as logical considerations regarding the arrangement or operational flow of steps, the plain meaning derived from grammatical structure or punctuation, or the number or type of components described in the specification.

[0332] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of the present invention. Other configurations will be apparent to those skilled in the art from consideration of the specification and practice described herein. It is intended that the specification and described configurations be considered exemplary only, with a true scope and spirit being indicated by the appended claims.

Claims

1. A device, a substrate having one or more polymeric materials; a layer disposed on the substrate, the layer comprising one or more conductive materials, the layer having a thickness of 12 micrometers or less, and a porosity of at least 5% by volume; 12. The device comprising: a battery electrode including:

2. The device of claim 1 , wherein the one or more conductive materials include at least one of copper, aluminum, titanium, nickel, or stainless steel.

3. The device of claim 1 , wherein the one or more polymeric materials have a glass transition temperature of 250° C. or less.

4. 10. The device of claim 1, wherein the one or more polymeric materials comprise at least one of polyethylene, polyethylene glycol, polypropylene, polyimide, polyetheretherketone, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polyacrylate, or polyethylene naphthalate.

5. The device of claim 1 , wherein the one or more conductive materials are formed as a multiplicity of particles having a spherical morphology.

6. The device of claim 1 , wherein the one or more conductive materials are formed as a multitude of particles having a nanowire morphology.

7. The device of claim 1 , wherein the layer comprises one or more electrode active materials.

8. The one or more electrode active materials correspond to the anode and include graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, and SnO. ２ , Si, Sn, lithium metal, LiNi ｘ Mn ｙ Co ｚ O ２ , LiNi ｘ Co ｙ Al ｚ O ２ , LiMn ｘ Ni ｙ O ｚ , LiMnO ２ , LiFePO ４ , LiMnPO ４ , LiNiPO ４ , LiCoPO ４ , LiV ２ O ５ , sulfur, or LiCoO ２ 8. The device of claim 7, comprising at least one of: x, y, and z are stoichiometric coefficients.

9. 8. The device of claim 7, wherein the layer comprises one or more bonding materials for bonding one or more electrode active materials with one or more conductive materials.

10. 10. The device of claim 9, wherein the one or more bonding materials comprise at least one of polyvinylidene fluoride, polyamideimide, polyethylene oxide, polyimide, polyacrylic acid, polymethyl methacrylate, polyvinyl alcohol, or polypropylene carbonate.

11. 10. The device of claim 9, wherein the layer includes one or more conductive additives comprising at least one of carbon black particles, carbon nanotubes, or graphite particles.

12. 10. The device of claim 1, wherein the layer is a current collector layer and the battery electrode includes an active material layer comprising one or more electrode active materials.

13. The device of claim 1 , wherein the layer comprises pores having diameters of 10 nanometers or less.

14. The device of claim 1 , wherein the substrate has a porosity of at least 5% by volume.

15. The device of claim 1 , wherein a thin encapsulating layer is formed over the one or more conductive materials.

16. 10. The device of claim 1, wherein the layer includes one or more flame retardant additives comprised of at least one of ammonium polyphosphate, ammonium sulfate, sodium borate, melamine, or pentaerythritol.

17. 10. The device of claim 1, wherein the layer comprises one or more first thermal management additives comprised of at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, or polyvinyl chloride.

18. 10. The device of claim 1, wherein the layer includes one or more second thermal management additives comprised of at least one of ethylene vinyl acetate, polyvinyl alcohol, polycaprolactone, silicone, polyurethane, or naphthalene.

19. providing a substrate for a battery electrode, the substrate comprising one or more polymeric materials; forming a layer on the substrate, the layer comprising one or more conductive materials, having a thickness of 12 micrometers or less, and having a porosity of at least 5% by volume; A method comprising:

20. 20. The method of claim 19, wherein forming a layer on the substrate comprises depositing an ink on the substrate.

21. 21. The method of claim 20, comprising subjecting the ink to one or more heat treatments after the ink is deposited on the substrate, wherein the one or more heat treatments are performed at a temperature of about 250° C. or less.

22. performing a solution phase coating process to form the layer on the substrate; 20. The method of claim 19, wherein the solution phase coating process comprises at least one of a slot die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip coating process.

23. The method of claim 20 , wherein the ink comprises first particles composed of one or more conductive materials and one or more solvents.

24. 24. The method of claim 23, wherein the one or more solvents comprise at least one of isopropyl alcohol, ethanol, methanol, tert-butanol, 1-butanol, 2-amino-2-methyl-1-propanol, amino-2-propanol, 2-methoxyethanol, ethylene glycol, dipropylene glycol monomethyl ether, diethylene glycol methyl ether, benzyl alcohol, pyridine, tetrahydrofuran (THF), hexane, toluene, or water.

25. 24. The method of claim 23, wherein the ink includes second particles comprising one or more electrode active materials.

26. the layer is a current collector layer, and the method comprises:

21. The method of claim 20, comprising forming an active material layer on the current collector layer, the active material layer comprising an active material of a battery electrode.

27. 27. The method of claim 26, wherein forming the active material layer on the current collector layer comprises depositing additional ink on the current collector layer.

28. 30. The method of claim 27, comprising applying one or more additional heat treatments to the additional ink after it is deposited on the current collector layer, wherein the one or more additional heat treatments are performed at a temperature of about 250° C. or less.

29. 30. The method of claim 28, comprising performing an additional solution phase coating process to form the active material layer on the current collector layer, the additional solution phase coating process comprising at least one of a slot die process, a spray process, an aerosol process, a bath process, a gravure coating process, a comma coating process, or a dip coating process.

30. 20. The method of claim 19, comprising: subjecting the substrate to one or more pretreatment processes prior to forming the layer on the substrate, the one or more pretreatment processes comprising at least one of ultraviolet light ozone, corona discharge, atmospheric pressure plasma, or applying one or more chemical solutions to the substrate.

31. 20. The method of claim 19, comprising subjecting at least one of the one or more conductive materials or one or more conductive material-active electrode material composites disposed on the substrate to one or more heat treatments, wherein the one or more heat treatments comprise at least one of optical flash sintering, spark plasma sintering, ultrasonic sintering, or microwave sintering.

32. one or more solvents; first particles composed of one or more conductive materials; second particles composed of one or more electrode active materials; A blend that includes:

33. 33. The formulation of claim 32, wherein the one or more conductive materials comprise at least one of copper, aluminum, titanium, nickel, or stainless steel.

34. 33. The formulation of claim 32, comprising an ink having the first particles and the second particles.

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