Release layers for alkali metals on plastic substrates

Abstract

An alkali metal-containing film stack for an energy storage device is provided. The alkali metal-containing film stack can be a lithium film stack having a flexible support layer and a release layer disposed on the flexible support layer, the release layer being separable from the flexible support layer. The release layer includes one or more nanosheets (e.g., two-dimensional materials). An alkali metal-containing layer (e.g., a lithium layer) is disposed on the release layer.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE

[0001] Embodiments of the present disclosure generally relate to electrode coatings and methods for coating electrodes.

[0002] 2. Description of Related Art

[0002] Lithium (Li)-ion batteries have played a key role in the development of current generations of mobile devices, microelectronics, and electric vehicles. A typical Li-ion battery consists of a positive electrode (cathode), a negative electrode (anode), an ion-conducting electrolyte, a porous separator membrane (electrical insulator) between the two electrodes to physically separate the electrodes, and a package.

[0003]

[0003] Lithium batteries typically contain graphite materials as anodes. The use of graphite can result in lower capacity compared to the use of silicon-blend graphite. Currently, the industry is transitioning from graphite-based anodes to silicon-blend graphite to increase energy cell density. Silicon-blend graphite anodes can exhibit first-cycle irreversible capacity loss (IRC). The specific energy and energy density of lithium-ion batteries are significantly reduced due to the loss of active lithium during first-cycle charging, where approximately 5 to 20 percent of the lithium from the cathode is consumed by solid electrolyte interphase formation ("SEI") in the anode.

[0004]

[0004] Prelithiation of anodes prior to the first cycle charge is a common strategy to compensate for active lithium loss. Furthermore, prelithiation provides other performance and reliability benefits to lithium-ion battery performance. For example, prelithiation can reduce the impedance of lithium-ion batteries, thereby improving their rate capability. Additionally, for silicon-based anodes, prelithiation can mitigate silicon cracking and shattering by pre-expanding the silicon and increasing the anode's mechanical stability.

[0005]

[0005] During prelithiation, current processes can release lithium into the environment. Therefore, there is a need for a process and protective layer added to the lithium surface that is stable to lithium at high temperatures and prevents lithium exposure to the environment.

[0006] overview

[0006] In one aspect, an alkali metal-containing film stack for an energy storage device is provided. The alkali metal-containing film stack includes a flexible support layer. A release layer is disposed on the flexible support layer and is separable from the flexible support layer. The release layer includes one or more nanosheets. An alkali metal-containing layer is disposed on the release layer.

[0007]

[0007] Embodiments may include one or more of the following: The film stack further includes an electrolyte-containing layer disposed between the release layer and the alkali metal-containing layer. The alkali metal-containing layer includes lithium. The film stack includes one or more additional film layers disposed between the flexible support layer and the alkali metal-containing layer, each of the one or more additional film layers having a melting point higher than a melting point of the alkali metal-containing layer. The flexible support layer includes a material selected from the group consisting of polyethylene terephthalate (PET), paper, and combinations thereof. The one or more nanosheets are selected from the group consisting of titanium disulfide (TiS2), tungsten disulfide (WS2), molybdenum disulfide (MoS2), boron nitride (BN), aluminum oxide hydroxide (AlHO2), MoO3, graphene, fluorocarbon (CF x The two-dimensional material is selected from the group consisting of: tungsten carbide, carbon nitride, layered double hydroxides, derivatives thereof, and combinations thereof. The alkali metal-containing layer is adhered to the anode. The release layer has a thickness of about 1 nm to about 500 nm. An energy storage device comprising an anode and a film stack disposed on the anode.

[0008] In another aspect, a method of making a storage device is provided. The method includes disposing a release layer on a flexible support layer. The release layer includes one or more nanosheets. The method includes evaporating an alkali metal onto the release layer and transferring the release layer and alkali metal to a substrate to form an energy storage device.

[0009]

[0009] Embodiments may include one or more of the following: the one or more nanosheets comprise a two-dimensional material, and the two-dimensional material is transferred to the flexible support layer by coating a roller with a powder comprising the two-dimensional material while the flexible support layer is conveyed over the surface of one or more rollers, and pressing the roller against the flexible support layer to transfer the powder from the roller to the flexible support layer; the one or more nanosheets comprise a two-dimensional material, and the two-dimensional material is transferred to the flexible support layer by pressing a solid comprising the two-dimensional material against the flexible support layer as the flexible layer is conveyed over the surface of the one or more rollers; pressing the solid comprises applying a spring tension to the solid in a direction perpendicular to the surface of the flexible support layer; the one or more nanosheets are deposited by chemical vapor deposition, atomic layer deposition, molecular layer deposition, physical vapor deposition, or a combination thereof; the method further comprises depositing an electrolyte-containing layer over the release layer. Plastic substrates can be activated using corona or plasma surface treatments for good adhesion of 2D materials.

[0010] In yet another aspect, a method of making an energy storage device is provided. The method includes disposing a release layer on a flexible support layer. The release layer includes a two-dimensional material. The method includes evaporating lithium onto the release layer to form a lithium layer. The method includes transferring the release layer and the lithium layer to a substrate to form the energy storage device.

[0011]

[0011] Embodiments may include one or more of the following: the release layer and the lithium layer are deposited in the same process chamber; the release layer is transferred onto the flexible support layer in a first chamber, and the lithium layer is deposited on the release layer in a second chamber; the method further includes depositing an electrolyte-containing layer on the release layer, where the electrolyte-containing layer is deposited in the first chamber or the second chamber; the release layer is transferred onto the flexible support layer in the first chamber, and the lithium layer is deposited on the release layer in the first chamber.

[0012] In another aspect, a non-transitory computer-readable medium stores instructions that, when executed by a processor, cause a process to perform the operations of the apparatus and / or method described above. [Brief explanation of the drawings]

[0013]

[0013] So that the features previously mentioned in this disclosure can be understood in detail, a more particular description of the disclosure briefly summarized above can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and therefore should not be considered limiting of the scope thereof, as other equally effective embodiments may be recognized. [Figure 1] 1A-1C show schematic cross-sectional views of lithium-containing film stacks according to some embodiments described herein. [Figure 2] 1A-1C show schematic cross-sectional views of lithium-containing film stacks having solid electrolyte layers according to some embodiments described herein. [Figure 3] 1 shows a schematic cross-sectional view of a deposition system according to some embodiments described herein. [Figure 4] 1 shows a schematic cross-sectional view of a deposition system according to some embodiments described herein. [Figure 5] 1 shows a schematic cross-sectional view of a two-dimensional material deposition apparatus according to some embodiments described herein. [Figure 6] 1 shows a schematic cross-sectional view of a two-dimensional material deposition apparatus according to some embodiments described herein. [Figure 7] 1 illustrates a system for transferring one or more layers of a film stack to a substrate according to some embodiments described herein. [Figure 8] FIG. 1 illustrates a block flow diagram of a process for forming an energy storage device according to some embodiments described herein.

[0014]

[0022] To facilitate understanding, the same reference numerals have been used, wherever possible, to designate identical elements common to the figures, and it is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0015] Detailed Description

[0023] Energy storage devices, such as lithium-ion batteries, typically include a positive electrode (e.g., a cathode) and a negative electrode (e.g., an anode) separated by multiple layers. All-solid-state batteries also typically include a positive electrode and a negative electrode and an ion-conducting material disposed therebetween. A solid electrolyte interfacial (SEI) layer is typically formed in situ during the formation cycle on the anode and cathode material surfaces. The SEI aids in the long-cycle performance of the cell.

[0016]

[0024] Substrate independent direct transfer (SIDT) is a method for forming lithium metal anodes and pre-lithiated anodes in energy storage devices to improve the life cycle of batteries. These anodes can include, but are not limited to, graphite, silicon, silicon graphite, silicon oxide graphite, silicon, metallized plastic, and copper. In the SIDT process, lithium is first deposited on a support layer composed of one or more materials (e.g., polyethylene terephthalate (PET), paper, or a combination thereof). The material on the support layer is transferred directly to the anode for pre-lithiation or to a current collector to form a lithium metal anode on the current collector. A release layer allows the lithium and other materials to be released from the support layer and transferred onto the anode.

[0017]

[0025] Conventional exfoliation layers remain on the support layer after transferring the lithium and other layers. This reduces the ability to reuse the support layer in a subsequent SIDT process. This also exposes the transferred lithium on the anode, which can affect device stability, especially at high temperatures. The apparatus and methods described herein enable the exfoliation layer to be transferred to the anode along with the lithium layer, where it acts as a protective layer on the lithium during transfer.

[0018]

[0026] FIG. 1 shows a schematic cross-sectional view of one embodiment of a SIDT film stack 100. SIDT film stack 100 includes a support layer 110, a release layer 120, and an alkali metal-containing layer 130 (e.g., a lithium-containing layer). In some embodiments, release layer 120 includes one or more nanosheets, e.g., one or more two-dimensional (2D) materials. In some embodiments, release layer 120 has a thickness of about 1 nm to about 500 nm, e.g., about 10 nm to about 300 nm, e.g., about 50 to about 200 nm. In some embodiments, release layer 120 includes multiple sublayers, each having a thickness of about 5 nm or less.

[0019]

[0027] As used herein, a "2D material" refers to an atomically thin crystalline solid with a single or a few layered structures. In some embodiments, the 2D materials herein have intralayer covalent bonds and interlayer van der Waals bonds. In some embodiments, the 2D materials may have properties selected from the group consisting of high carrier mobility, superconductivity, mechanical flexibility, high thermal conductivity, high optical and UV absorption, peel strength on silicone of about 3 to about 100 grams force / inch, weak interlayer bonds, and combinations thereof. Peel strength can be measured using a 25 mm wide TESA 7475 test tape at a peel angle of 180° and a peel rate of 300 mm / min (3M method). Without being bound by theory, it is believed that selecting a 2D material with weak interlayer bonds allows for easier subsequent peeling of the release layer from the support layer. In some embodiments, each layer of the SIDT stack 100 may have a melting temperature higher than the melting temperature of the alkali metal-containing layer.

[0020]

[0028] In some embodiments, each layer can have a melting point that is equal to each additional layer and / or that decreases with each additional layer, such that the support layer 110 has the highest melting point, the release layer has a lower melting point than the support layer, and the alkali metal-containing layer has the lowest melting point. In some embodiments, the two-dimensional material can be titanium disulfide (TiS), tungsten disulfide (WS), molybdenum disulfide (MoS), boron nitride (BN), aluminum oxide hydroxide (AlHO), MoO, graphene, fluorocarbon (CF), or other suitable materials. x ), carbon nitride, layered double hydroxides, derivatives thereof, and combinations thereof. In some embodiments, the 2D material comprises a metal nitride, a metal sulfide, a metal hydroxide, a carbon-containing material, derivatives thereof, or combinations thereof.

[0021]

[0029] In some embodiments (which can be combined with other embodiments), support layer 110 can be or include one or more layers selected from plastic, polymeric material, metallized plastic, metal, paper, multilayers thereof, or combinations thereof. Examples of suitable polymeric materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose triacetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonate (PC), multilayers thereof, or combinations thereof. In some embodiments (which can be combined with other embodiments), support layer 110 is a flexible support layer, such as a web-based substrate.

[0022]

[0030] FIG. 2 shows a schematic cross-sectional view of a SIDT film stack 200. The SIDT film stack 200 includes a support layer 210, a release layer 220, a solid electrolyte-containing layer 240, and an alkali metal-containing layer 230 (e.g., a lithium layer). The SIDT film stack 200 can be formed and transferred onto a substrate similar to the SIDT film stack 100 of FIG. 1. The solid electrolyte-containing layer 240 is between the release layer 220 and the alkali metal-containing layer 230. In some embodiments, the electrolyte is a metal salt, such as a lithium salt. Lithium salts include LiPF, LiAsF, LiCF, LiN(CF), LiN(CF), LiBF, Li-borohydride (Li(CB), Li(H ... 10 )-0.3Li(CB 11 H 12)), LiClO4BETT electrolyte, or a combination thereof. The electrolyte may be present in a gel or polymer matrix medium. Other additional layers are also contemplated to be disposed between the release layer 220 and the alkali metal-containing layer 230. In some embodiments (which may be combined with other embodiments), a dielectric layer 250 may optionally be included in the SIDT film stack 200. The dielectric layer 250 may be lithium fluoride, aluminum oxide, aluminum oxide hydroxide, boron nitride, carbon nitride, titanium oxide, lithium titanium oxide, zirconium oxide, tantalum oxide, barium titanate, lithium zirconium oxide, molybdenum oxide, silicon oxide, lithium silicon oxide, or a combination thereof. In some embodiments (which may be combined with other embodiments), a metal layer 260 may optionally be included in the SIDT film stack 200. The metal layer 260 may include silver, copper, aluminum, silicon, or a combination thereof. In some embodiments (which can be combined with other embodiments), a passivation layer 270 may optionally be included in the SIDT film stack 200. In some embodiments, the passivation layer 270 includes an alkali metal carbonate in the alkali metal-containing layer 230. In some embodiments (which can be combined with other embodiments), the alkali metal-containing layer 230 is a lithium layer, and the passivation layer 270 includes lithium carbonate. The passivation layer 270 may be formed by exposing the alkali metal-containing layer 230 to carbon dioxide. In some embodiments, the alkali metal-containing layer 230 is exposed to carbon dioxide in the presence of heat to form a passivation layer containing a carbonated alkali metal. Without being bound by theory, it is believed that the carbon dioxide reacts with the alkali metal to form a thin layer of alkali metal carbonate on the exposed surface of the alkali metal-containing layer 230. In some embodiments, the passivation layer 270 (e.g., a lithium carbonate passivation layer) may have a thickness ranging from about 50 nm to about 100 nm. The passivation layer 270 may serve as a protective layer for the underlying alkali-metal-containing layer 230 .For example, passivation layer 270 can protect the underlying alkali-metal-containing layer 230 from oxidation and damage during storage and transportation.

[0023]

[0031] The SIDT film stacks described herein are formed such that an alkali metal-containing layer (e.g., a lithium layer) is deposited last on the SIDT film stack. Depositing the lithium layer last allows the film stack to be formed without damaging the lithium layer, which typically has a lower melting point than other materials formed in the energy storage device. Conventional methods for forming energy storage devices include depositing lithium directly on the anode. These methods also include maintaining the underlying substrate as the lithium layer is formed to prevent lithium damage. In contrast, the SIDT film stacks and methods described herein allow the alkali metal-containing layer 230 (e.g., a lithium layer) to be formed last before transferring the entire SIDT film stack to the substrate.

[0024]

[0032] 3 shows a schematic diagram of a deposition system viewed along the axis of rotation of a drum 310. The drum 310 is rotatable about the axis of rotation. The deposition system is suitable for forming the SIDT film stacks described herein, according to some embodiments. A deposition system for coating a web substrate guided over a rotatable coating drum is referred to herein as a roll-to-roll (R2R) deposition system. Here, the web substrate is the support layer 110.

[0025]

[0033] In some embodiments, the support layer 110 is continuously transported through the deposition system along rollers (not shown) at either end of the system that store the film stack by a combination of guide wheels 360 and drum 310. The support layer 110 is transported along the deposition system against the curved substrate support surface of the drum 310. The guide wheels 360 maintain the support layer 110 tightly against the drum 310, which causes the support layer 110 to lie flat against the drum 310 and to be substantially free of folds or wrinkles on the support layer 110 as the flexible support layer is wound onto the drum 310.

[0026]

[0034] Vaporized 2D material can be deposited onto a flexible support layer from first vapor distribution assembly 300A as the substrate is transported relative to the surface of drum 310. Multiple nozzles 321 of first vapor distribution assembly 300A are aimed at curved drum surface 311, and a deposition system is configured to move support layer 110 on curved drum surface 311 past first vapor distribution assembly 300A. The nozzles are positioned a distance D away from support layer 110. In some embodiments, the flexible support layer is continuously transported along the drum, thereby continuously depositing vaporized 2D material onto support layer 110.

[0027]

[0035] Material can be delivered from an evaporation crucible 330 to a vapor distributor 320 for vaporizing the material. The vapor distributor 320 includes multiple nozzles 321 for directing evaporated material in the evaporation crucible toward the support layer 110 to form a coating (e.g., a release layer) on the support layer 110. The evaporation crucible 330 is in fluid communication with the vapor distributor 320 via a conduit 350. In some embodiments, the conduit 350 is a linear connecting tube or passage. In some embodiments, the vapor distributor 320 is a vapor distribution showerhead having multiple nozzles arranged in a one- or two-dimensional pattern for directing the evaporated material toward the support layer 110. During evaporation, the vapor distributor 320 is typically at a second temperature higher than the first temperature inside the evaporation crucible 330 to prevent condensation of material on the interior wall surfaces of the vapor distributor.

[0028]

[0036] In some embodiments, several vapor distribution assemblies 300A-300C as described herein may be sequentially positioned circumferentially around a rotatable coating drum 310 so that the substrate 110 can be subsequently coated by several evaporation sources. Different coating materials can be deposited on the substrate 110, or a single thicker coating layer of the same coating material can be deposited on the substrate 110 by the evaporation sources.

[0029]

[0037] The vapor distribution assemblies 300A-300C can be arranged in any order to form one or more layers on the support layer 110 of the SIDT film stack. In some embodiments, the first vapor distribution assembly 300A is configured to deposit a release layer on the support layer 110. The second vapor distribution assembly 300B is configured to deposit a solid electrolyte-containing layer on the release layer. In some embodiments, the third vapor distribution assembly 300C is configured to deposit a lithium layer on the release layer or the electrolyte-containing layer. Each vapor distribution assembly can define a coating window on the curved drum surface 311 that extends over an angular range (a) of 10° to 45°.

[0030]

[0038] In some embodiments (which may be combined with other embodiments described herein), the deposition apparatus further includes an edge exclusion shield 340 extending from at least one or more deposition assemblies 300A-C toward the curved drum surface 311. The edge exclusion shield may include an edge exclusion portion 331 for masking areas of the substrate that are not to be coated, such as for masking lateral edge areas of the support layer that are to be kept free of coating material. For example, the edge exclusion portion 331 may be configured to mask two opposing lateral edges of the support layer.

[0031]

[0039] The edge exclusion portion 331 may extend in the circumferential direction T along the curved drum surface 311 of the drum 310, following the curvature of the curved drum surface 311. In this way, the gap width D between the curved drum surface 311 and the edge exclusion portion 331 can be kept small (e.g., 2 mm or less) and substantially constant along the circumferential direction T, thereby improving edge exclusion accuracy and allowing sharp, well-defined coating layer edges to be deposited on the substrate.

[0032]

[0040] As used herein, the "circumferential direction T" may be understood as the direction along the circumference of the drum 310 that corresponds to the direction of movement of the curved drum surface 311 as the rotatable drum rotates about its axis. The circumferential direction T corresponds to the direction of substrate transport as the substrate moves past the evaporation source on the curved drum surface 311. In some embodiments, the drum 310 may have a diameter ranging from about 300 mm to about 1400 mm, or larger.

[0033]

[0041] In some embodiments, the entire SIDT film stack is formed in a single process chamber. Alternatively, one or more layers of the SIDT film stack are deposited in a first process chamber 410, and one or more layers of the SIDT film stack are deposited in one or more additional process chambers (e.g., a second process chamber 420). The first process chamber 410 and / or the second process chamber 420 can each be a vapor deposition system, such as the vapor deposition system described in connection with FIG. 3. In some embodiments (e.g., the system shown in FIG. 4), the first process chamber 410 includes a single evaporation source 402, and the second process chamber 420 includes one or more vapor distribution assemblies 400A, 400B, 400C, and 400D. The evaporation source 402 and one or more vapor distribution assemblies 400A-400D can be any of the evaporation assemblies 300A-300C, as shown in FIG. 3. In some embodiments, the first process chamber includes a mechanical system for transferring the release layer. Examples of mechanical systems useful for transferring the release layer are shown and described in connection with Figures 5 and 6.

[0034]

[0042] 5 illustrates a mechanical transfer system 500 for transferring a release layer to a support layer. The mechanical transfer system 500 includes a feed assembly 510, e.g., a funnel-shaped feed assembly configured to receive granular material 570 and transfer the granular material 570 to an outer surface of a first roller 530A. The first roller 530A can be actuated by a second rotating roller 530B. In some embodiments, the surface of the first roller 530A includes an adhesive to hold the granular material 570 on the surface of the first roller 530A prior to transferring the granular material 570. In some embodiments, a blade 520 is coupled to the feed assembly 510 and configured to contact the top layer of granular material 570 on the first roller 530A at a uniform thickness.

[0035]

[0043] The substrate 550 from roll 564 is continuously fed between two rollers (first roller 530A and pivot roller 560) onto roll 562. Before transferring the substrate 550 through the first roller 530A and pivot roller 560, the substrate 550 is exposed to a plasma or corona treatment 540, which sterilizes the substrate 550. The substrate 550 is then continuously fed through the first roller 530A and pivot roller 560. The granular material 570 adheres to the surface of the first roller 530A and is pressed against the substrate 550 as it moves through the first roller 530A and pivot roller 560. The granular material 570 is transferred from the first roller 530A onto the substrate 550, forming a release layer on the substrate 550. The support layer 550 with the release layer can be transferred or continuously conveyed to a deposition chamber where other layers can be deposited onto the support layer 550 and / or the release layer. Other mechanical methods of transferring two-dimensional materials are also contemplated.

[0036]

[0044] FIG. 6 shows an alternative mechanical transfer system 600 for mechanically transferring a release layer onto a support layer 650. The support layer 650 is fed from a roll 642 to a roll 644. Between rolls 642 and 644, the support layer 650 is conveyed between a block of solid 2D material 620 and a roller 630. In some embodiments, the support layer 650 is exposed to a plasma or corona treatment 640, which sterilizes the support layer 650 before transferring the 2D material thereon. The block of solid 2D material 620 is held against the support layer 650 by applying a force normal to the surface of the support layer 650. In some embodiments, the force is provided by a spring 610 such that a constant force is maintained on the block of 2D material 620 toward the support layer 650. As the block of solid 2D material 620 is held against the support layer 650, a layer of 2D material is transferred from the block of 2D material 620 to the support layer 650, forming a release layer on the support layer. The support layer 650 with the release layer can be transferred or transported to a deposition chamber where other layers can be deposited thereon.

[0037]

[0045] Once the SIDT film stack is fully formed, a portion or layer of the SIDT film stack can be transferred to a substrate to form an energy storage device. In some embodiments, the SIDT film stack can include a polyethylene terephthalate (PET) layer, a release layer, a dielectric layer, a metal layer, a lithium or lithium alloy layer, and a surface passivation layer. The dielectric layer can include lithium fluoride, aluminum oxide, aluminum oxide hydroxide, boron nitride, carbon nitride, titanium oxide, lithium titanium oxide, zirconium oxide, tantalum oxide, barium titanate, lithium zirconium oxide, molybdenum oxide, silicon oxide, lithium silicon oxide, and combinations thereof. The metal layer can include silver, copper, aluminum, silicon, or combinations thereof. In some embodiments, the SIDT film stack is laminated and calendered before transfer.

[0038]

[0046] A system 700 for transferring layers from a SIDT film stack 706 to a substrate 708 is shown in Figure 7. The SIDT film stack 706 and substrate 708 may be conveyed together between two rollers 702, 704. In some embodiments, the support layer of the SIDT film stack interfaces with the surface of roller 702, and the lithium layer of the SIDT film stack interfaces with the substrate 708. Rollers 702, 704 (e.g., stainless steel rollers) may be heated to a temperature that allows the release layer, lithium layer, and other layers to be transferred from the support layer to the substrate and pressed together.

[0039]

[0047] FIG. 8 shows a process flow diagram of a method 800 for forming an energy storage device. The method 800 includes, in operation 802, disposing a release layer on a flexible support layer. The release layer can be deposited or mechanically transferred onto the support layer using one or more of the systems described herein. The release layer includes one or more nanosheets. The one or more nanosheets include a two-dimensional material. In some embodiments, the one or more nanosheets are deposited by chemical vapor deposition, atomic layer deposition, molecular layer deposition, physical vapor deposition, or a combination thereof. In some embodiments, the flexible support layer is conveyed over one or more rollers while the 2D material is transferred to the flexible support layer by coating the roller with the granular 2D material and pressing the roller against the flexible support layer to transfer the powder from the roller to the flexible support layer.

[0040]

[0048] In operation 804, an additional layer can be included on the release layer, for example, by evaporating an alkali metal onto the release layer. In some embodiments, an ion-conducting electrolyte-containing layer is formed on the release layer before transferring the alkali metal to the release layer. The alkali metal can be lithium, which is useful for use in energy storage devices. In some embodiments, the metal (e.g., lithium) is evaporated in an evaporation crucible (e.g., any of the evaporation crucibles described herein). The evaporation crucible is heated to a temperature of about 500°C or higher, for example, from about 600°C to about 1200°C, for example, from about 700°C to about 1000°C.

[0041]

[0049] In operation 806, the release layer and alkali metal layer are transferred to a substrate to form an energy storage device, for example, using the system 700 described in FIG. 7. The substrate can be a flexible substrate such as a CPP film (i.e., cast polypropylene film), an OPP film (i.e., oriented polypropylene film), or a PET film (i.e., polyethylene terephthalate film). Alternatively, the flexible substrate can be precoated paper, a polypropylene (PP) film, a PEN film, a polylactic acid (PLA) film, or a PVC film. The substrate can further include one or more current collectors, which can include aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, alloys thereof, and combinations thereof.

[0042]

[0050] In some embodiments, at least one of the current collectors is perforated. In one embodiment, at least one of the current collectors comprises a polymer substrate (e.g., polyethylene terephthalate (“PET”)) coated with a metallic material. In one embodiment, the anode current collector is a polymer substrate (e.g., a PET film) coated with copper. In another embodiment, the anode current collector is a multi-metal layer on a polymer substrate. The multi-metal layer can be copper, chromium, nickel, a combination of alloys thereof, or any combination thereof. In one embodiment, the anode current collector is a multi-layer structure comprising a copper-nickel clad material. In one embodiment, the multi-layer structure comprises a first layer of nickel or chromium, a second layer of copper formed on the first layer, and a third layer comprising nickel, chromium, or both formed on the second layer. In one embodiment, the anode current collector is nickel-coated copper. In one embodiment, the anode current collector is graphite-coated copper. Additionally, the current collector can be of any form factor (eg, metal foil, sheet, or plate), shape, and micro / macro structure.

[0043]

[0051] In some embodiments, the thickness of the anode is from about 10 μm to about 200 μm (e.g., from about 1 μm to about 100 μm, from about 10 μm to about 30 μm, from about 20 μm to about 30 μm, from about 1 μm to about 20 μm, or from about 50 μm to about 100 μm).

[0044]

[0052] The embodiments of the present disclosure described above have many advantages, including the following: The methods and SIDT film stacks described herein enable the formation of lithium-containing film stacks that can be transferred to anodes for use in energy storage devices. When the layers of the SIDT film stack are transferred, the release layer is transferred along with the lithium layer, protecting the lithium layer. However, the present disclosure does not require that every advantageous feature and every benefit be incorporated into every embodiment of the present disclosure.

[0045]

[0053] In the Abstract, as well as in the specification and claims, and in the accompanying drawings, reference is made to particular features (including method operations) of the present disclosure. It should be understood that the disclosure herein includes all possible combinations of such particular features. For example, if a particular feature is disclosed in the context of a particular aspect, embodiment, embodiment, or example of the present disclosure, or a particular claim, that feature can also be used in the present disclosure generally, to the extent possible in combination with and / or in the context of other particular aspects and embodiments of the present disclosure.

[0046]

[0054] The term "comprises" and its grammatical equivalents are used herein to mean that other elements, ingredients, operations, etc. are optionally present. For example, an article "comprising" (or "which comprises") elements A, B, and C can consist of elements A, B, and C (i.e., include only elements A, B, and C), or it can include not only elements A, B, and C, but also one or more other elements. Furthermore, whenever a element, component, or group of elements is preceded by the transitional phrase "comprising" or its grammatical equivalent, it is understood that the same composition or group of elements may also be preceded by the transitional phrase "consisting essentially of," "consisting of," "selected from the group consisting of," or "is," and vice versa.

[0047]

[0055] When reference is made herein to a method including two or more specified operations, the specified operations may be performed in any order, or simultaneously (unless the context excludes this possibility), and the method may include one or more other operations performed before any of the specified operations, between two of the specified operations, or after all of the specified operations (unless the context excludes this possibility).

[0048]

[0056] While the forgoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope, which scope is defined by the following claims.

Claims

1. 1. An alkali metal-containing film stack for an energy storage device, comprising: flexible support layer, a release layer disposed on and separable from the flexible support layer, the release layer comprising one or more nanosheets; and an alkali metal-containing layer disposed on the release layer; 1. A film stack comprising:

2. The film stack of claim 1 , further comprising an electrolyte-containing layer disposed between the release layer and the alkali metal-containing layer.

3. The film stack of claim 1 , wherein the alkali metal-containing layer comprises lithium.

4. 10. The film stack of claim 1, wherein the film stack includes one or more additional film layers disposed between the flexible support layer and the alkali metal-containing layer, the one or more additional film layers each having a melting point higher than the melting point of the alkali metal-containing layer.

5. 10. The film stack of claim 1, wherein the flexible support layer comprises a material selected from the group consisting of polyethylene terephthalate (PET), paper, and combinations thereof.

6. The one or more nanosheets are titanium disulfide (TiS ２ ), tungsten disulfide (WS ２ ), molybdenum disulfide (MoS ２ ), boron nitride (BN), aluminum oxide hydroxide (AlHO ２ ), MoO ３ 10. The film stack of claim 1, comprising a two-dimensional material selected from the group consisting of: graphene, carbon nitride, layered double hydroxides, derivatives thereof, and combinations thereof.

7. The film stack of claim 1 , wherein the alkali metal-containing layer is adhesive to an anode.

8. 10. The film stack of claim 1, wherein the release layer has a thickness of from about 1 nm to about 500 nm.

9. An energy storage device comprising an anode and the film stack of claim 1 disposed on the anode.

10. 1. A method of making an energy storage device, comprising: disposing a release layer comprising one or more nanosheets on a flexible support layer; evaporating an alkali metal onto the release layer; and transferring the release layer and the alkali metal to a substrate to form an energy storage device; A method comprising:

11. 11. The method of claim 10, wherein the one or more nanosheets comprise a two-dimensional material, and the two-dimensional material is transferred to the flexible support layer by coating a roller with a powder comprising the two-dimensional material while the flexible support layer is being conveyed over the surface of one or more rollers, and pressing the roller against the flexible support layer to transfer the powder from the roller to the flexible support layer.

12. 11. The method of claim 10, wherein the one or more nanosheets comprise a two-dimensional material, and the two-dimensional material is transferred to the flexible support layer by pressing a solid comprising the two-dimensional material against the flexible support layer as the flexible layer is conveyed over the surface of one or more rollers.

13. The method of claim 12 , wherein compressing the solid body comprises applying a spring tension force to the solid body in a direction perpendicular to a surface of the flexible support layer.

14. 11. The method of claim 10, wherein the one or more nanosheets are deposited by chemical vapor deposition, atomic layer deposition, molecular layer deposition, physical vapor deposition, or a combination thereof.

15. The method of claim 10 further comprising depositing an electrolyte-containing layer over the release layer.

16. 1. A method of making an energy storage device, comprising: disposing a release layer comprising a two-dimensional material on the flexible support layer; evaporating lithium onto the release layer to form a lithium layer; and transferring the release layer and the lithium layer to a substrate to form an energy storage device; A method comprising:

17. 17. The method of claim 16, wherein the exfoliation layer and the lithium layer are deposited in the same process chamber.

18. 17. The method of claim 16, wherein the release layer is transferred onto the flexible support layer in a first chamber and the lithium layer is deposited onto the release layer in a second chamber.

19. 20. The method of claim 18, further comprising depositing an electrolyte-containing layer over the release layer, wherein the electrolyte-containing layer is deposited in the first chamber or the second chamber.

20. 17. The method of claim 16, wherein the release layer is transferred onto the flexible support layer in a first chamber and the lithium layer is deposited onto the release layer in the first chamber.

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