Seed layer for lithium transfer and passivation

Abstract

Embodiments of the present disclosure generally relate to film stacks for electronic devices and to methods of forming film stacks including lithium anodes and pre-lithiated anodes for energy storage devices. The method includes forming a seed layer over a flexible support layer and depositing a lithium metal layer on the seed layer. The method also includes laminating the lithium metal layer to a flexible receiving substrate, and separating the lithium metal layer from the flexible support layer. The seed layer acts as a release layer for the lithium metal layer. At least a portion of the seed layer is transferred with the lithium metal layer to provide the lithium metal layer with passivation.

Description

SEED LAYER FOR LITHIUM TRANSFER AND PASSIVATIONBACKGROUNDField

[0001] Implementations of the present disclosure generally relate to film stacks for electronic devices and methods of forming film stacks.Description of the Related Art

[0002] High-capacity electrochemical energy storage devices, such as lithium-ion (Li-ion) batteries, are used in a growing number of applications, including portable electronics, medical, transportation, grid-connected large energy storage, renewable energy storage, and uninterruptible power supply (UPS).

[0003] Lithium metal layers play a vital role in the development of Li-ion batteries. Lithium is an alkali metal. Like the heavy element homologs of the first periodic table group, lithium is characterized by a strong reactivity with a variety of substances. Lithium reacts violently with water, alcohols and other substances that contain protic hydrogen, often resulting in ignition. Lithium is unstable in air and reacts with oxygen, nitrogen and carbon dioxide. As such, due to its strong reactivity properties, lithium is normally handled under an inert gas atmosphere (noble gases such as argon). As a result, lithium provides several challenges when it comes to processing, storage, and transportation.

[0004] Therefore, what is needed in the art is an improved method of transferring lithium metal layers for forming film stacks.SUMMARY

[0005] In an embodiment, a method for forming a seed layer over a flexible support layer is provided. The method includes depositing a lithium metal layer on the seed layer, laminating the lithium metal layer to a flexible receiving substrate, and separating the lithium metal layer from the flexible support layer to transfer the lithium metal layer to the receiving substrate. When the lithium metal layer is transferred, at least a portion of the seed layer is transferred with the lithium metal layer to the receiving substrate to provide the lithium metal layer with passivation.1SUBSTITUTE SHEET RULE 26

[0006] In another embodiment, a method for forming a film stack for an energy storage device is provided. The method includes disposing a flexible support layer in a vacuum environment and forming a seed layer over the flexible support layer. The seed layer comprises LiF, Li2CO3, Ag, Bi, Sn, Ag+LiF, Bi+LiF, Sn+LiF, AgF, CxFy, or a combination thereof. The method also includes depositing a lithium metal layer on the seed layer, laminating the lithium metal layer to a flexible receiving substrate, and transferring the lithium metal layer from the flexible support layer to the flexible receiving substrate to form the film stack. The seed layer assists in releasing the lithium metal layer from the flexible support layer, and at least a portion of the seed layer is transferred with the lithium metal layer to the flexible receiving substrate.

[0007] In a further embodiment, a film stack for an energy storage device is provided. The film stack includes a flexible receiving substrate, a lithium metal layer disposed on the flexible receiving substrate, and a seed layer disposed over at least a portion of the lithium metal layer. The seed layer provides the portion of the lithium metal layer disposed between the seed layer and the flexible receiving substrate with passivation. The lithium metal layer and the seed layer are also transferred to the flexible receiving substrate from a flexible support layer in which the seed layer acts as a release layer for separating the lithium metal layer from the flexible support layer.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to implementations, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary implementations and are therefore not to be considered limiting of its scope, and may admit to other equally effective implementations.

[0009] Figure 1 illustrates a flowchart showing selected operations of a method of forming an energy storage device in accordance with one or more implementations of the present disclosure.2SUBSTITUTE SHEET RULE 26

[0010] Figures 2A-2G illustrate views of various stages of manufacturing the energy storage device according to the method of Figure 1 , in accordance with one or more implementations of the present disclosure.

[0011] Figure 3 illustrates a flowchart showing selected operations of a method of forming an energy storage device, in accordance with one or more implementations of the present disclosure.

[0012] Figures 4A-4E illustrate views of various stages of manufacturing the energy storage device according to the method of Figure 3, in accordance with one or more implementations of the present disclosure.

[0013] Figure 5 illustrates a schematic view of manufacturing the energy storage device according to the method of Figure 3, in a lamination transfer apparatus, in accordance with one or more implementations of the present disclosure.

[0014] Figure 6 illustrates a schematic view of a flexible substrate coating apparatus, in accordance with one or more implementations of the present disclosure.

[0015] Figure 7 illustrates a schematic view of a lamination transfer apparatus, in accordance with one or more implementations of the present disclosure.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one implementation may be beneficially incorporated in other implementations without further recitation.DETAILED DESCRIPTION

[0017] The present disclosure generally relates to processes for transferring metal layers using release layers. In particular, implementations relate to methods using a deposited seed layer configured to act as a release layer and a surface passivation layer when forming anode film stacks.

[0018] Transferring lithium metal layers onto substrates is an important process in microfabrication of microelectronic devices and energy storage devices. Substrate independent direct transfer (SIDT) is a method for forming anode film stacks by transferring one or more layers including an alkali metal layer, for example, a lithium3SUBSTITUTE SHEET RULE 26metal layer, to a substrate stack, for example, a current collector in implementations where lithium metal functions as an anode or for pre-lithiating an anode material which is already formed on the current collector. The already formed anode material can include or be, but is not limited to, graphite, silicon, silicon graphite, silicon oxide graphite, silicon, or combinations thereof. The current collector can include or be metalized plastic, copper, or combinations thereof. In SIDT processes, lithium is formed over a flexible support layer stack composed of one or more materials such as a polymer substrate, for example, polyethylene terephthalate (PET), paper, or combinations thereof. The materials formed on the flexible support layer stack are directly transferred / laminated to a substrate stack. The substrate stack can include or be a current collector, a current collector having anode material formed thereover, a metallized plastic substrate, a separator, or a metallized plastic substrate having lithium formed thereover.

[0019] Conventional methods of transferring the materials formed on the flexible support layer stack often involve the use of a release layer formed between the alkali metal layer and the flexible support layer stack. The release layer enables transferring lithium and other materials off of the flexible support layer stack and onto the current collector or anode material if already present. Such conventional release layers are often pre-fabricated on the flexible support layer stack and vary in thickness, release pressure, particles, and pinholes. The varying and uncontrollable properties of the release layer can cause process variations during SIDT. As a result, following SIDT, materials such as trace amounts of the release layer can remain on a surface of the lithium of the formed film stack.

[0020] However, the release layer materials are often not compatible with end uses such as electrochemical devices. For example, the release layer chemistry may not be compatible with the end device (for example, a battery) and can instead impede ion or electronic transport. That is, the release layer chemistry can cause an increase in the cell impedance between the anode and separator interface which is generally undesirable as it can affect the overall cell performance of the battery. Additionally, unwanted reactions of the release layer with gases (for example, H2O, O2, N2, etc.) during handling, shipping, and subsequent integration can impact device integration.4SUBSTITUTE SHEET RULE 26

[0021] A method of depositing a seed layer for use as both a release layer in SIDT to transfer lithium metal layers as well as a surface passivation layer after the lithium metal layers are transferred is described below. The SIDT process of the disclosure is described in implementations of Figure 1. In one or more implementations, which can be combined with other implementations, the seed layer is deposited on the flexible support layer in a vacuum chamber prior to the forming of the lithium metal layers. The seed layer enables a release layer with consistent quality, engineered control, and tailored to act as a surface passivation layer when the anode film stack is formed. Depositing the seed layer in a vacuum also provides an engineering opportunity for the development of high quality pristine interface layers and the forming of the anode film stack all without breaking vacuum.

[0022] One or more implementations of the present disclosure also provide for improved interface control using vacuum deposition without breaking vacuum. The method can be incorporated in a roll-to-roll tool and used in a roll-to-roll process as described in implementations of Figure 3. Roll-to-roll manufacturing of interface layers provides a high volume manufacturing solution, which includes substrate independent deposition and transfer (SIDT) of a lithium anode film stack. High quality lithium metal can be deposited on the seed layer just before lamination transfer to preserve the highest quality materials in the film stack.

[0023] It is noted that while the particular substrate on which some implementations described herein can be practiced is not limited, it is particularly beneficial to practice the implementations on flexible substrates, including for example, web-based substrates, panels and discrete sheets. The flexible substrate can also be in the form of a foil, a film, or a thin plate.

[0024] It is also noted here that a flexible substrate or web as used within the implementations described herein can typically be characterized in that it is bendable. The term “web” can be synonymously used to the term “strip,” the term “flexible substrate,” or the term “flexible conductive substrate.” For example, the web as described in implementations herein can be a polymer material.

[0025] Figure 1 illustrates a flow chart of a method 100 of manufacturing an energy storage device in accordance with one or more implementations of the present disclosure. Figures 2A-2G are views of various stages of manufacturing the energy5SUBSTITUTE SHEET RULE 26storage according to the method 100 of Figure 1 . The method 100 describes forming a SIDT stack 255 on a flexible support layer 210 and then transferring the SIDT stack 255 to a receiving substrate 260 to form an anode film stack 265. Although Figures 2A-2G are described in relation to the method 100, it will be appreciated that the structures disclosed in Figures 2A-2G are not limited to the method 100, but instead may stand alone as structures independent of the method 100. Similarly, although the method 100 is described in relation to Figures 2A-2G, it will be appreciated that the method 100 is not limited to the structures disclosed in Figures 2A-2G but instead may stand alone independent of the structures disclosed in Figures 2A-2G.

[0026] It should be understood that Figures 2A-2G illustrate only partial schematic views of the energy storage device, and the energy storage device may contain any number of additional layer and / or additional materials common to energy storage devices, which are not shown for the sake of brevity. It should also be noted that although the method 100 illustrated in Figure 1 is described sequentially, other process sequences that include one or more operations that have been omitted and / or added, and / or have been rearranged in another desirable order, fall within the scope of the implementations of the disclosure provided herein.

[0027] Referring to Figure 2A, at operation 101 , the flexible support layer 210 of a flexible support layer stack 200 is provided. The flexible support layer 210 has a front side 21 Of (also referred to as a front surface) and a backside 210b (also referred to as a back surface) opposite the front side 21 Of. The flexible support layer 210 may comprise any suitable material that is compatible with the targeted processing conditions.

[0028] In some implementations, the flexible support layer includes a plurality of sub-layers. In one or more implementations, which can be combined with other implementations, the flexible support layer 210 can be or include, one or more sublayers selected from plastic, polymer materials, metallized plastic, metals, paper, multilayers thereof, or a combination thereof. Example of suitable polymer materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose tri-acetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof.6SUBSTITUTE SHEET RULE 26

[0029] In one or more implementations, which can be combined with other implementations, the flexible support layer 210 has a thickness in a range from about 1 micron to about 100 microns, or in a range from about 1 micron to about 100 microns, or in a range from about 10 microns to about 50 microns, or in a range from about 25 microns to about 50 microns.

[0030] Referring to Figure 2B, at operation 102, a seed layer 220 is formed over the flexible support layer 210. The seed layer 220 is formed on the front side 21 Of of the flexible support layer 210. The seed layer 220 has a front side 220f (also referred to as a front surface) and a backside 220b (also referred to as a back surface) opposite the front side 220f. In one or more implementations, the seed layer 220 is formed on the front side 21 Of of the flexible support layer 210 such that the backside 220b of the seed layer 220 contacts the front side 21 Of of the flexible support layer 210. In other implementations, the flexible support layer 210 may be pre-fabricated with a release layer disposed on the front side 21 Of. In such implementations, the seed layer 220 is formed over the release layer disposed on the flexible support layer 210.

[0031] The seed layer 220 may be or include any material suitable for both releasing the SIDT stack 255 from the flexible support layer 210 during the SIDT process, and providing a passivation layer for the SIDT stack 255 thereafter. Depositing the seed layer 220 on the flexible support layer 210 and the alkali metal layer (e.g., the lithium metal layer 250) thereafter to form the SIDT stack 255 advantageously provides custom control over the seed layer 220 used which can enable both improved manufacturing efficiency and improved electrochemistry performance of the SIDT stack 255 formed. For example, in some implementations, the alkali metal layer may be deposited directly in contact with the seed layer 220. The chemistry and reaction between the seed layer 220 and the subsequently deposited alkali metal layer may therefore be controlled such that the seed layer 220 or a reaction between the seed layer 220 and the layers of the SIDT stack 255 does not result in an ohmic layer that increases the cell impedance between the anode and separator interface.

[0032] In one or more implementations, the seed layer 220 as implemented to provide passivation to the alkali-metal layer (e.g., the lithium metal layer 250 in the SIDT stack 255) may be configured such that the electrochemistry between the seed7SUBSTITUTE SHEET RULE 26layer 220 and the lithium metal layer 250 deposited thereon improves the electrochemical performance of the SIDT stack in energy storage devices. For example, the seed layer 220 may be configured so as not to impede ion or electron transport in battery cell architecture thereby keeping the impedance of the anode film stack formed less than about 200 ohms / cm2. In some embodiments, the seed layer 220 keeps the impedance of the anode film stack formed between about 5 ohms / cm2and about 200 ohms / cm2.

[0033] In one or more implementations, which can be combined with other implementations herein, the seed layer 220 may be selected from LiF, Li2CO3, Ag, Bi, Sn, Ag+LiF, Bi+LiF, Sn+LiF, AgF, CxFy, or a combination thereof. The composition of the seed layer 220 may also be selected based on the specific battery chemistries and applications thereof the anode film stack to be formed is intended to be used with. In one or more implementations, which may be combined with other implementations, the material of the seed layer 220 may be selected and tailored based on the chemistry and reaction with the alkali metal layer to be deposited on the seed layer 220 and the specific battery chemistries and applications thereof the anode film stack to be formed is intended to be used with.

[0034] Any suitable process may be used to form the seed layer 220 on the front side of the flexible support layer 210. In some implementations, the seed layer 220 may be deposited using vapor deposition techniques, for example, sputtering, reactive sputtering, evaporation, physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enabled chemical vapor deposition (PECVD) or other similar vapor deposition processes. In one or more implementations, which can be combined with other implementations, the seed layer 220 is deposited using a mixed process gas of Ar and CO2. Forming the seed layer 220 via vapor deposition techniques advantageously enables and provides control to engineer the thickness, release pressure, particles, and pinholes in the seed layer 220, thereby ensuring consistent, predictable, and high-quality lithium transfer. For example, in one or more implementation, the depositing of the seed layer 220 via vapor deposition in a vacuum provides control over the flexible support layer 210 provided and the forming of the seed layer 220 thereover. Such control enables mitigating and reducing particles and pinhole defects that may otherwise be induced by the flexible support layer 210 when the seed layer 220 is being deposited.8SUBSTITUTE SHEET RULE 26

[0035] In one or more implementations, the polymer material of the flexible support layer 210 and / or the seed layer 220 is selected so that the SIDT stack 255 can be debonded from the flexible support layer 210 by pressure initiated lift off. In other implementations, the seed layer 220 may be configured to be debonded by laser initiated lift off. Without being bound by theory, it is believed that the seed layer 220 configured with a weak interlayer bonding enables ease of subsequently separating the seed layer 220 from the flexible support layer 210. In one or more implementations, the seed layer 220 may be configured with a release pressure between about .3 gram force / cm2and about 16 gram force / cm2.

[0036] The seed layer 220 may also be deposited under atmospheric conditions, near atmospheric conditions, or vacuum conditions. In one or more implementations, the seed layer 220 may be deposited using vacuum processes in vacuum environment such as a vacuum chamber. In one implementation, the seed layer 220 can be deposited in a vacuum environment between about 1 x 10’3mbar and about 1 x 10’6mbar, such as below about 1 x 10’2mbar or below about 1 x 10’4mbar. In some implementations, prior to operation 102, the flexible support layer 210 may be transferred into a vacuum coating system, for example, the flexible substrate coating apparatus 600 shown in Figure 6. The seed layer 220 may then be deposited under vacuum in a roll-to-roll deposition system using the flexible substrate coating apparatus 600.

[0037] In some implementations, the seed layer 220 may include a single layer of a material deposited on the flexible support layer 210 in which the seed layer 220 is capable of separating from the flexible support layer 210 during SIDT and act as a passivation layer thereafter. In others implementations, the seed layer 220 may comprise a plurality of sub-layers of different materials deposited on the flexible support layer 210. In such implementations, certain sub-layers of the seed layer 220 may be configured to separate from one another during SIDT to facilitate the release of the SIDT stack 255 from the flexible support layer 210. In such implementations, the sub-layer of the seed layer 220 transferred with the SIDT stack 255 may then act as the surface passivation layer for the SIDT stack 255 thereafter.

[0038] In one or more implementations, which can be combined with other implementations herein, the seed layer 220 has a thickness in a range from about 19SUBSTITUTE SHEET RULE 26nm to about 5,000 nm, such as about 10 nm to about 1000 nm, and about 100 nm to about 500 nm. In some implementations, the seed layer 220 includes a plurality of sub-layers, each layer having a thickness of about 50 nm or less. In one or more implementations, the thickness of the seed layer 220 may be tailored based on the release pressure desired for separating the SIDT stack 255 from the flexible support layer 210.

[0039] In one or more implementations, which can be combined with other implementations herein, the seed layer 220 can be patterned or selectively deposited to create localized lithium deposition areas for customized battery designs. Since the seed layer 220 functions as the release layer for separating the SIDT stack 255 from the flexible support layer 210 during SIDT, the seed layer 220 may be patterned or selectively deposited for local interface debonding to transfer a corresponding SIDT stack 255 to the receiving substrate 260. In one or more implementations, which may be combined with other implementations discussed herein, the seed layer 220 may therefore be patterned or selectively deposited on the flexible support layer 210 to transfer the lithium metal layer 250 on the receiving substrate 260.

[0040] Referring to Figure 2C, optionally at operation 103, a solid electrolyte layer 230 is formed over the seed layer 220. The solid electrolyte layer 230 has a front side 230f (also referred to as a front surface) and a backside 230b (also referred to as a back surface) opposite the front side 230f. In one or more implementations, the solid electrolyte layer 230 is deposited on the front side 220f of the seed layer 220 such that the backside 230b of the solid electrolyte layer 230 contacts the front side 220f of the seed layer 220. Any suitable process may be used to form the solid electrolyte layer 230 on the front side 220f of the seed layer 220. The solid electrolyte layer 230 may be deposited using non-vacuum coating techniques.

[0041] The solid electrolyte layer 230 may comprise any suitable material that is compatible with the targeted ion conducting. In some implementations, the solid electrolyte layer 230 can include or be a metal salt, such as lithium salt. The lithium salt can be one or more of LiPFe, LiAsFe, LiCFsSOs, LiN(CF3SO3)3, LiBFe, LiCICMBETTE electrolyte, or combinations thereof. The electrolyte can be in a gel or polymer matrix medium.10SUBSTITUTE SHEET RULE 26

[0042] In one or more implementations, the solid electrolyte layer 230 can be or include materials selected from fluorocarbons (PTFE, PVDF), LiF, Li2CO3, MgO, AIOx, AIHO2, RENiO3 (RE=rare earth), BN, BaTiO3, Li4Ti5O12, ZrO2, TiO2, silicon doped lithium tantalum phosphates, for example, Li(1 +x)Ta2P(1-x)SixO8, Li1.5Ta2P0.5Si0.5O8, lithium tantalum phosphates, for example, LiTa2PO8 (LTPO), Li2Ta2SiO8 (LTSO), Li0.34La0.56TiO3, lithium aluminum titanium phosphates, for example, Li1 ,3AI0.3Ti1 ,7(PO4)3 (LATP), lithium aluminum germanium phosphates, for example, Li1.3AI0.3Ge1.7(PO4)3 (LAGP), garnet Li7La3Zr2O12 (LLZO), or a combination thereof.

[0043] In one or more implementations, the solid electrolyte layer 230 may be formed using non-vacuum coating techniques. Suitable coating techniques include, but are not limited to, a slot-die coating process, a doctor-blade coating process, a three-dimensional (3D) printing process, or a combination thereof. In one or more alternative implementations, the solid electrolyte layer 230 may be formed using vacuum coating techniques. In some implementations, the solid electrolyte layer 230 may be deposited using the flexible substrate coating apparatus 600 shown in Figure 6.

[0044] Referring to Figure 2D, optionally at operation 104, one or more interface layers 240 are formed over the solid electrolyte layer 230. The interface layers 240 are disposed between the seed layer 220 and a lithium metal layer 250. The interface layers 240 can include or be at least one of an interface dielectric material, a plating and stripping enhancement layer, and a lithiophilic layer. The interface layers 240 may be deposited under vacuum. The interface layers 240 may be deposited under vacuum in a roll-to-roll deposition system, for example, the solid electrolyte layer 230 may be deposited using the flexible substrate coating apparatus 600 shown in Figure 6. The interface layers 240 may be deposited by vapor deposition techniques, for example, chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), such as thermal evaporation or sputtering.

[0045] The interface dielectric layer may be selected from AIOx, AIOOH, LiF, BaTiO3, ZrO2, TiO2, Li4Ti5O12, LiAIO2, AIF3, BiF3, AgFx, rare earth (RE) nickelates (RENiO3), or a combination thereof. RE can be a trivalent rare-earth. RE can be lanthanide. RE can be selected from La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Y, Lu, or a11SUBSTITUTE SHEET RULE 26combination thereof. RE can be selected from Sm, Nd, and Eu. The RE nickelates can be doped with ions. Suitable ions for doping include lithium ions, sodium ions, magensium ions, potassium ions, hydrogen ions, and aluminum ions. In one example, the RE nickelate is SmNiO3 doped with lithium ions. The plating and stripping enhancement layers may be or include alloys of metals or chalcogenides. The plating and stripping enhancement layers may be or include Ag, Bi, Sn, Si, Cu, alloys of metals or chalcogenides of Ag, Bi, Sn, Si, Cu, or a combination thereof. The lithiophilic layer may be or include at least one of: a metal including Al, Au, Ag, Bi, Pt, Zn, Si, Sn, Mg, In, Ga, or Cu, alloys thereof, or a metal oxide including Li4Ti5O12, RENiO3, AIOx, CuO, ZnO, CoO, or MnO.

[0046] In one or more implementations, which can be combined with other implementations, the one or more interface layers 240 include a dielectric layer. The dielectric layer can be lithium fluoride, aluminum oxide, aluminum hydroxide oxide, 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.

[0047] In one or more implementations, which can be combined with other implementations, the one or more interface layers 240 include a plating and stripping enhancement layer(s). The plating and stripping enhancement layer(s) can include a metallic layer. The metallic layer can be or include silver, bismuth, tin, copper, aluminum, silicon, or a combination thereof. The plating and stripping enhancement layer(s) can include a metallic layer. The metallic layer can be or include silver, bismuth, tin, copper, aluminum, silicon, indium, gallium, or a combination thereof. The plating and stripping enhancement layers may be selected from Ag, Bi, Sn, Si, Cu, Al, alloys of metals or chalcogenides of Ag, Bi, Sn, Si, or a combination thereof.

[0048] In one or more implementations, which can be combined with other implementations, the one or more interface layers 240 include a lithiophilic layer. The one lithiophilic layer may enable lateral growth of the subsequently deposited lithium metal layer 250. The lithiophilic layer may be or include a metal or a metal oxide. The lithiophilic layer may be or include at least one of: a metal including Al, Au, Ag, Bi, Pt, Zn, Si, Sn, Mg, In, Ga, or Cu, alloys thereof, or a metal oxide including Li4Ti5O12, RENiO3, AIOx, CuO, ZnO, CoO, or MnO. The lithiophilic layer may be deposited by12SUBSTITUTE SHEET RULE 26at least one process selected from the group of immersing, spin coating, dip coating, spray coating, doctor blade coating, solution casting, drop coating, PVD, and CVD.

[0049] In one or more implementations, which can be combined with other implementations, a passivation layer can optionally be included in the SIDT stack 255, such as by being formed prior to the deposition of the lithium metal layer 250. Forming a surface passivation in the SIDT stack 255 prior to the deposition of the lithium metal layer 250 provides the lithium metal layer 250 with immediate protection (e.g., by the surface passivation layer) after lamination transfer of the SIDT stack 255 to the receiving substrate 260. As discussed above, the seed layer 220 may be configured to act as a release layer for separating the SIDT stack 255 from the flexible support layer 210 in the lamination transfer of the lithium metal layer 250. At least a portion of the seed layer 220 is configured to transfer to the receiving substrate 260 with the SIDT stack 255 to provide passivation for the anode film stack 265 formed thereafter. The seed layer 220 described herein may therefore improve manufacturing efficiency by avoiding the need for the additional step of forming a passivation layer prior to depositing the lithium metal layer 250, while still offering the same benefit and advantageous by providing passivation for the anode film stack 265 to be formed.

[0050] Referring to Figure 2E, in operation 105, a lithium metal layer, for example the lithium metal layer 250 is formed over the front side 220f of the seed layer 220. The lithium metal layer 250 includes a front side 230f (also referred to as a front surface) and a backside 230b (also referred to as a back surface) opposite the front side 230f. In some implementations, where any of the solid electrolyte layer 230 and the one or more interface layers 240 are present, the lithium metal layer 250 may be formed directly on the underlying layers, for example, any of the solid electrolyte layer 230 and the one or more interface layers 240. In some implementations, where the solid electrolyte layer 230 and the one or more interface layers 240 are not present, the lithium metal layer 250 may be formed directly on the front side 220f of the seed layer 220.

[0051] The lithium metal layer 250 may be or include lithium. The lithium metal layer 250 may be deposited under vacuum. The lithium metal layer 250 may be deposited under vacuum in a roll-to-roll deposition system, for example, the flexible substrate coating apparatus 600 shown in Figure 6. In some implementations,13SUBSTITUTE SHEET RULE 26operations 102 - 105 may all be performed using the same flexible substrate coating apparatus 600 shown in Figure 6, thereby enabling the seed layer 220 and the SIDT stack 255 formed thereon to all be deposited on the flexible support layer 210 without breaking vacuum. The lithium metal layer 250 may be deposited via a physical vapor deposition process, for example, an evaporation process or a sputtering process. The evaporation process may be an electron beam evaporation process or a thermal evaporation process.

[0052] Referring to Figure 2E, the lithium metal layer 250 completes the flexible support layer stack 200. The seed layer 220, the solid electrolyte layer 230 (if present), the one or more interface layers 240 (if present), and the lithium metal layer 250 form the SIDT stack 255. In some implementations, the SIDT stack 255 may include only a portion of the seed layer 220.

[0053] The SIDT stacks 255 described herein are formed such that the lithium metal layer 250 is deposited last on the flexible support layer stack 200. Depositing the lithium layer last enables forming the SIDT stack 255 without damaging the lithium layer, which typically has a lower melting point relative to other materials that are formed in energy storage device. Conventional methods of forming energy storage devices include direct deposition of molten lithium onto the current collector in lithium metal anode formation or onto the anode material in pre-lithiation implementations. These methods further include maintaining the underlying substrate as the lithium metal layer 250 is formed to prevent damage to the lithium. In contrast, the flexible support layer stack 200 and methods described herein, enable forming the lithium metal layer 250 last prior to transferring the SIDT stack 255 to the receiving substrate 260 during operation 106.

[0054] In some implementations, which can be combined with other implementations, a passivation layer can optionally be included in the SIDT stack 255. In some implementations, the passivation layer includes a carbonate of the alkali metal in the alkali metal-containing layer (e.g., the lithium metal layer 250). In some implementations, which can be combined with other implementations, the alkali metalcontaining layer is a lithium metal layer, as in the lithium metal layer 250, and the passivation layer comprises lithium carbonate. The passivation layer can be formed by exposure of the lithium metal layer 250 to carbon dioxide. In some14SUBSTITUTE SHEET RULE 26implementations, the lithium metal layer 250 is exposed to carbon dioxide in the presence of heat. Without wishing to be bound by theory, it is believed that the carbon dioxide reacts with the lithium metal to form a thin layer of lithium carbonate on the exposed surface of the lithium metal layer 250. In some implementations, the carbonated lithium metal passivation layer, for example, the lithium carbonate passivation layer, can have a thickness ranging from about 50 nm to about 100 nm. The carbonated lithium passivation layer can serve as a protective layer for the lithium metal layer 250. For example, the carbonated lithium metal passivation layer can protect the lithium metal layer 250 from oxidation and damage during storage and shipping.

[0055] After operation 105 and prior to operation 105, the flexible support layer stack 200 including the SIDT stack 255 may be transferred from a vacuum coating system, for example, the flexible substrate coating apparatus 600 shown in Figure 6 to a lamination transfer apparatus, for example, the lamination transfer system 700 shown in Figure 7. The lamination transfer process may include applying the receiving substrate 260 to the front side 250f of the lithium metal layer 250 and removing the SIDT stack 255 from the flexible support layer 210 to form an anode film stack 265. As discussed above, removing the SIDT stack 255 from the flexible support layer 210 may comprise separating the seed layer 220 from the flexible support layer 210, or separating certain sub-layers of the seed layer 220.

[0056] Referring to Figure 2G, at operation 106, the SIDT stack 255 is transferred from the flexible support layer 210 to the receiving substrate 260 to form the anode film stack 265. As shown, operation 106 may include lamination transfer onto a current collector to form the anode film stack 265. In some implementations, where pre-l ithiation is involved, an anode material may already be formed over the receiving substrate 260 and the lithium metal layer 250 is transferred to the anode material formed over the receiving substrate 260. The receiving substrate 260 may be or include flexible film, such as a CPP film (i.e., a casting polypropylene film), an OPP film (i.e., an oriented polypropylene film), or a PET film (i.e., a polyethylene terephthalate film). Alternatively, the receiving substrate 260 may be a pre-coated paper, a polypropylene (PP) film, a PEN film, a polylactic acid (PLA) film, or a PVC film. The receiving substrate 260 can be or include one or more current collectors, the current collector can include aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni),15SUBSTITUTE SHEET RULE 26cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, alloys thereof, and a combination thereof. In various implementations, the receiving substrate 260 can be or includes copper or copper foil.

[0057] In one or more implementations, which can be combined with other implementations, during operation 106 the seed layer 220 is transferred or partially transferred with the SIDT stack 255 as is shown in Figure 2F. As discussed above, once transferred, the seed layer 220 also acts as a surface passivation layer for the anode film stack 265. The seed layer 220 can serve as a protective layer for the lithium metal layer 250. For example, the seed layer 220 can protect the lithium metal layer 250 from oxidation and damage during storage and shipping.

[0001] Referring to Figure 2G, at operation 107 the anode film stack 265 may optionally be combined with a separator 290, a cathode stack 285, or both the separator 290 and the cathode stack 285 to form an energy storage device 295. In some embodiments, the energy storage device 295, even though shown as a planar structure in Figure 2G may also be formed into a cylinder by rolling the stack of layers; furthermore, other cell configurations (e.g., prismatic cells, button cells, or stacked electrode cells) may be formed.

[0002] The separator 290 may include a microporous polymeric separator including a polyolefin, by way of a non-limiting example. The polyolefin may be a homopolymer (derived from a single monomer constituent) or a heteropolymer (derived from more than one monomer constituent), which may be either linear or branched. If a heteropolymer is derived from two monomer constituents, the polyolefin may assume any copolymer chain arrangement, including those of a block copolymer or a random copolymer. Similarly, if the polyolefin is a heteropolymer derived from more than two monomer constituents, it may likewise be a block copolymer or a random copolymer. In certain implementations, the polyolefin may be polyethylene (PE), polypropylene (PP), or a blend of PE and PP, or multi-layered structured porous films of PE and / or PP. Commercially available polyolefin porous membranes include CELGARD® 2500 (a monolayer polypropylene separator) and CELGARD® 2320 (a tri-layer polypropylene / polyethylene / polypropylene separator) available from Celgard LLC.16SUBSTITUTE SHEET RULE 26

[0003] In one or more implementations, which can be combined with other implementations the cathode stack 285 includes a cathode current collector 280 and cathode material 270. The cathode current collector 280 may be or include any of the flexible films described and aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), tin (Sn), silicon (Si), manganese (Mn), magnesium (Mg), alloys thereof, and combinations thereof. The cathode current collector 280 may be or include any of aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), tin (Sn), silicon (Si), manganese (Mn), magnesium (Mg), alloys thereof, and combinations thereof. In some implementations, the cathode current collector 280 may be or include aluminum.

[0004] The cathode material 270 may be or include any suitable cathode material. The cathode material 270 or cathode may be or include any material compatible with the anode and may include an intercalation compound, an insertion compound, or an electrochemically active polymer. Suitable intercalation materials include, for example, sulfur, lithium-containing metal oxides, M0S2, FeS2, MnO2, TS2, NbSes, LiCoO2, LiNiC>2, LiMnC , LiMn2O4, VeO and V2O5. Suitable polymers include, for example, polyacetylene, polypyrrole, polyaniline, and polythiophene. In some implementations, the cathode material 270 includes a polymer binder material as described herein. The cathode material 270 or cathode may be or include a layered oxide, such as lithium cobalt oxide, an olivine, such as lithium iron phosphate, or a spinel, such as lithium manganese oxide. Examples of lithium-containing oxides may be layered, such as lithium cobalt oxide (LiCoC ), or mixed metal oxides, such as LiNixCoi-2xMnO2, LiNiMnCoO2 (“NMC”), LiNio.5Mn1.5O4, Li(Nio.8Coo.i5Alo.o5)02, LiMn2O4, and doped lithium rich layered-layered materials, wherein x is zero or a nonzero number. Examples of phosphates may be or include iron olivine (LiFePO4) and it is variants (such as LiFe(i-x)MgxPO4), LiMoPCM, LiCoPO4, LiNiPCM, Li3V2(PO4)3, LiVOPO4, LiMP2O?, or LiFei.sP2O7, wherein x is zero or a non-zero number. Examples of fluorophosphates may be or include LiVPCUF, LiAIPCUF, LisV(PO4)2G2 LisCr(PO4)2G2 Li2CoPO4F, or Li2NiPO4F. Example of silicates may be or include Li2GeSiO4, Li2MnSiO4, or Li2VOSiO4. Examples of non-lithium compounds may be or include NasV2(PO4)2G3.

[0005] Figure 3 illustrates a flow chart of a method 300 for manufacturing an energy storage device in accordance with one or more implementations of the present17SUBSTITUTE SHEET RULE 26disclosure. Figures 4A-4F illustrate views of various stages of manufacturing the energy storage device according to the method 300 of Figure 3. Although Figures 4A- 4E are described in relation to the method 300, it will be appreciated that the structures disclosed in Figures 4A-4E are not limited to the method 300, but instead may stand alone as structures independent of the method 300. Similarly, although the method 300 is described in relation to Figures 4A-4E, it will be appreciated that the method 300 is not limited to the structures disclosed in Figures 4A-4E but instead may stand alone independent of the structures disclosed in Figures 4A-4E.

[0006] It should be understood that Figures 4A-4E illustrate only partial schematic views of the energy storage device, and the energy storage device may contain any number of additional layer and / or additional materials common to energy storage devices, which are not shown for the sake of brevity. It should also be noted that although the method 300 illustrated in Figure 3 is described sequentially, other process sequences that include one or more operations that have been omitted and / or added, and / or have been rearranged in another desirable order, fall within the scope of the implementations of the disclosure provided herein.

[0007] Referring to Figure 4A, at operation 301 , a flexible support layer stack 400 is provided. The flexible support layer stack 400 includes at least a flexible support layer 410, a seed layer 420, and a lithium metal layer 430. The flexible support layer 410, the seed layer 420, and the lithium metal layer 430 corresponds with the flexible support layer 210, the seed layer 220, and the lithium metal layer 250 as described herein with respect to method 100. The seed layer 420 may be disposed over the flexible support layer 410 as described in operation 102. The lithium metal layer 430 may be disposed over the seed layer 420 as described in operation 105.

[0008] After operation 301 , the flexible support layer stack 400 having the lithium metal layer 430 or a SIDT stack 435 formed thereon may be transferred from a vacuum coating system, for example, the flexible substrate coating apparatus 600 shown in Figure 6 to a lamination transfer apparatus, for example, the lamination transfer system 700 shown in Figure 7. The lamination transfer process may include applying the receiving substrate to a front side 430f of the lithium metal layer 430 and removing the flexible support layer 410 from the SIDT stack 435 to form an anode film stack 465.18SUBSTITUTE SHEET RULE 26

[0009] In one or more implementations, which can be combined with other implementations, optionally, at operation 302, the flexible support layer stack 400 having the lithium metal layer 430 formed thereon is exposed to a pre-heat process prior to the lamination process at operation 303. As shown in Figure 4B, the pre-heat process can include exposing the lithium metal layer 430 to thermal energy, for example, a thermal energy 438 provided by an IR lamp source. In some implementations, where the lithium metal layer 430 is a thicker layer, pre-heating the lithium metal layer 430 can facilitate or accelerate the lamination process. In some implementations, the pre-heat temperature can be in a range between about 30 degrees Celsius and about 200 degrees Celsius. In some implementations, the preheat time can be between about 1 second and about 90 seconds. However, the preheat time may vary based on the speed the receiving substrate 440 and the flexible support layer 410 are conveyed through the lamination transfer system 700. For example, in some implementations, the receiving substrate 440 and the flexible support layer 410 may be conveyed through the lamination transfer system 700 between about 0.2 meters / min and about 25 meters / min, such as between about 0.5 meters / min and about 10 meter / min.

[0010] Referring to Figure 4C, at operation 303, the lithium metal layer 430 is laminated to a receiving substrate 440. The receiving substrate 440 can include one or more layers. In some implementations, for example, for a lithium metal anode device, the receiving substrate 440 can include a current collector. In some implementations, for example, for a pre-lithiation process, the receiving substrate 440 can include an anode material formed over a current collector. In yet other implementations, the receiving substrate 440 can be or include a separator and / or a cathode stack, for example, the separator 290 and the cathode stack 285 as shown in Figure 2G.

[0011] In one or more implementations, which can be combined with other implementations, the receiving substrate 440 includes a web-based substrate, for example, the current collector can be a web-based substrate. Any suitable current collector may be used. The current collector can include or be, but is not limited to, aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, metallized plastic, paper, stainless steel, metal mesh, metal foils, or a combination thereof. Any suitable anode material19SUBSTITUTE SHEET RULE 26may be used. The anode material can include or be, but is not limited to, graphite, silicon, silicon graphite, silicon oxide graphite, silicon, or combinations thereof.

[0012] During the lamination process of operation 303, the lithium metal layer 430 is contacted to the receiving substrate 440. For example, the front side 430f of the lithium metal layer 430 is contacted to a surface of the receiving substrate 440 as shown in Figure 4C. In some implementations, where the receiving substrate 440 only includes a current collector, the front side 430f of the lithium metal layer 430 is contacted to a surface of the current collector. In some implementations, where the receiving substrate 440 includes the anode material, the front side 430f of the lithium metal layer 430 is contacted to a surface of the anode material to pre-l ithiate the anode material.

[0013] In some implementations, operations 302 and 303 may occur simultaneously, sequentially, or partially overlap.

[0014] Referring to Figure 4D, optionally, at operation 304, pressure is applied to one or more of the receiving substrate 440 and the flexible support layer stack 200 having the lithium metal layer 430 formed thereon to laminate the receiving substrate 440 to the lithium metal layer 430. In some implementations, where the method 300 is performed in a roll-to-roll tool, web tension is sufficient to laminate the lithium metal layer 430 to the receiving substrate 440 and additional pressure is not needed. In some implementations, where additional pressure is used to laminate the lithium metal layer 430 to the receiving substrate 440, the lamination process includes pressing the lithium metal layer 430 to the receiving substrate 440 with a magnitude of pressure sufficient to attach the lithium metal layer 430 to the receiving substrate 440 without damaging the lithium metal layer 430. In other words, the pressure is such that the lithium metal layer 430 is not mechanically destroyed or degraded, such as by cracking or crushing.

[0015] Pressure may be applied using any suitable techniques. In one or more implementations, pressure is applied via a calendering process. The calendering process may include using a pair of calendering rollers 442a, 442b as is shown in Figure 4D. For example, pressure may be applied to the backside 410b of the flexible support layer 410 and a backside 440b of the receiving substrate 440. In one or more other implementations, pressure is applied by a vacuum source. In one or more other20SUBSTITUTE SHEET RULE 26implementations, the pressure is external pressure. In one or more implementations, the pair of calendering rollers 442a, 442b may also be heated.

[0016] In some implementations, operations 303 and 304 may occur simultaneously, sequentially, or partially overlap.

[0017] Referring to Figure 4E, at operation 305, the flexible support layer 410 is separated from the SIDT stack 435 to form the anode film stack 465 on the receiving substrate 440. Upon removal of the flexible support layer 410, the lithium metal layer 430 is disposed between at least a portion of the seed layer 420 on one end of the anode film stack 465, and the receiving substrate 440 on an opposite end of the anode film stack 465. The seed layer 420 or portion of the seed layer 420 disposed at the end of the anode film stack 465 may then also function as a surface passivation layer for the lithium metal layer 430 disposed between the seed layer 420 and the receiving substrate 440. The surface passivation layer may include the seed layer 420 or certain sub-layers of the seed layer 420.

[0018] At operation 306, the anode film stack 465 can be integrated with a separator, a cathode stack, or both the separator and the cathode stack as described above in operation 107 and shown in Figure 2G and to form the energy storage device.

[0019] Figure 5 illustrates a schematic view of a transfer system 500 for manufacturing the energy storage device according to the method of Figure 3 in a roll- to-roll tool and used in a roll-to-roll process using for example, the lamination transfer system 700 shown in Figure 7. In one or more implementations, which can be combined with other implementations, the lamination transfer process of operations 303 and 305 may comprise transferring lithium metal layers 530, 532 from separate SIDT stacks to opposite sides of the flexible receiving substrate 540. SIDT stacks including lithium metal layers 530, 532 and seed layers 520, 522 disposed on flexible support layers 510, 512, respectively, may each be provided as discussed in operation 301.

[0020] The transfer system 500 includes a first flexible carrier supply hub 515 and a second flexible carrier supply hub 525. A supply roll 511 of the flexible support layer 510 is positioned on the first flexible carrier supply hub 515. The supply roll 511 can include the lithium metal layer 530 and the seed layer 520 formed on the flexible21SUBSTITUTE SHEET RULE 26support layer 510. A supply roll 521 of the flexible support layer 512 is positioned on the second flexible carrier supply hub 525. The supply roll 511 can include the lithium metal layer 532 and the seed layer 522 formed on the flexible support layer 512.

[0021] The transfer system 500 also includes a flexible receiving substrate supply hub 535. A supply roll 531 of the flexible receiving substrate 540 is positioned on the flexible receiving substrate supply hub 535. The supply roll 511 and supply roll 521 are conveyed through the calendering units 550 such that the lithium metal layer 530 on the flexible support layer 510 faces the upper surface 540U of the flexible receiving substrate 540, and the lithium metal layer 532 on the flexible support layer 512 faces the lower surface 540L of the flexible receiving substrate 540.

[0022] The transfer system 500 further includes the calendering unit 550. The calendering unit 550 includes one or more calendering rollers, for example, the first calender roller 551 and the second calender roller 582. The flexible support layer 510, the flexible support layer 512, and the flexible receiving substrate 540 are arranged to be conveyed along a path that extends between through the calendering unit 550. The flexible receiving substrate 540 is positioned between the flexible support layer 510 and the flexible support layer 512 when the flexible support layer 510, the flexible support layer 512, and the flexible substrate stack 1540 are conveyed between the first calender roller 551 and the second calender roller 582. The first and second calender rollers 551 , 582 exert a high amount of pressure on the flexible support layers 510, 512 and the flexible receiving substrate 540 that causes the SIDT stacks on each of the flexible support layers 510, 512 to be transferred to the flexible receiving substrate 540. In some implementations, first and second calender rollers 551 , 582 may also be heated to facilitate laminating and transfer of the lithium metal layers 530, 532. Thereafter, tension is applied to the flexible support layers 510, 512 by first and second calender rollers 582, 584 to peel each of the flexible support layers 510, 512 away from the flexible receiving substrate 540 and form a film stack 560.

[0023] The transfer system 500 includes a first flexible carrier pickup hub 516 and a second flexible carrier pickup hub 526. A pickup roll 512 of the flexible support layer 510 is positioned on the first flexible carrier pickup hub 516. A pickup roll 522 of the second flexible carrier 412 is positioned on the second flexible carrier pickup hub 526. The lithium metal layer 530 and the seed layer 520 are no longer on the flexible22SUBSTITUTE SHEET RULE 26support layer 510 when the flexible support layer 510 is wound onto the first flexible carrier pickup hub 516 as the lithium metal layer 530 and the seed layer 520 previously on the first flexible carrier 110 are transferred onto the flexible receiving substrate 540 by the calendering rollers 551 , 582. Likewise, the lithium metal layer 532 and the seed layer 522 are no longer on the flexible support layer 512 when the flexible support layer 512 is wound onto the second flexible carrier pickup hub 526 because the lithium metal layer 532 and the seed layer 522 previously on the flexible support layer 512 are also transferred onto the flexible receiving substrate 540 by the calendering rollers 551 , 582. In some implementations, rollers 582, 584 may alternatively be configured as pick-up hubs with corresponding pick-up rolls to recapture or reclaim the flexible support layers 510, 512.

[0024] The transfer system 500 includes a flexible substrate stack pickup hub 570. A pickup roll 562 of the flexible receiving substrate 540 is positioned on the flexible substrate stack pickup hub 570. The flexible receiving substrate 540 includes the film stack 560 in which the lithium metal layer 530 is disposed between the seed layer 520 the upper surface 540U of the flexible receiving substrate 540, and the lithium metal layer 532 is disposed between the seed layer 522 and the lower surface 540L of the flexible receiving substrate 540. Seed layers 520, 522 in film stack 560 may act as surface passivation layers for the lithium metal layers 530, 532. The film stack 560 may then be conveyed to the flexible substrate pickup roll 570.

[0025] The transfer system 500 further includes a plurality of rollers 581-584. In some implementations, each of the rollers 581 -584 can be passive rollers. The rollers 581-584 can assist in applying proper tension to and assist in changing the direction of the flexible support layers 510, 512 and the flexible receiving substrate 540 during the movement of each of the flexible support layers 510, 512 and the flexible receiving substrate 540 through the different portions of the transfer system 500. Some of the rollers 581 -584 can also assist in moving the flexible support layers 510, 512 closer to or further away from the flexible receiving substrate 540. For example, the first roller 581 can assist in bringing the flexible support layers 510, 512 into contact with the flexible receiving substrate 540 before the flexible support layers 510, 512 and the flexible receiving substrate 540 are conveyed through the calendering unit 550. Additionally, the second and third calender rollers 582, 583 provide a location at which tension can be applied to the flexible support layers 510, 512 to peel the flexible23SUBSTITUTE SHEET RULE 26support layers 510, 512 away from the flexible receiving substrate 540. In some implementations, one or more of the rollers 581-584 can instead be a bar, such as metal bar, that can apply tension to the carrier or flexible substrate during the movement of the carrier or flexible substrate.

[0026] The transfer system 500 can further include a housing 517 disposed around an interior volume 508. The housing 517 can be used to maintain a separate environment in the interior volume 508 relative to the environment surrounding the transfer system 500. For example, the interior volume 508 can have different concentrations of gases as well as a different temperature and / or pressure relative to the environment surrounding the transfer system 500.

[0027] Figure 6 illustrates a schematic view of a flexible substrate coating apparatus 600 for forming at least a portion of the anode film stack described in accordance with one or more implementations of the present disclosure. The flexible substrate coating apparatus 600 may be a roll-to-roll coating system. The flexible substrate coating apparatus 600 may be used to perform portions of the methods 100 and 300 described herein that may be performed using vacuum deposition.

[0028] The flexible substrate coating apparatus 600 may be a SMARTWEB®, manufactured by Applied Materials, adapted for manufacturing lithium anode devices according to the implementations described herein. According to some implementations, the flexible substrate coating apparatus 600 can be used for manufacturing lithium anodes or pre-lithiated anodes, and particularly for portions of SIDT stacks 255 containing lithium films. The flexible substrate coating apparatus 600 is constituted as a roll-to-roll system including an unwinding module 602, a processing module 604 and a winding module 606. In one or more implementations, the processing module 604 comprises a plurality of processing modules or chambers 610, 620, 630 and 640 arranged in sequence, each configured to perform one processing operation to the continuous sheet of material 650 or web of material, for example, the flexible support layer 210 or the flexible support layer stack 200. In one or more implementations, as depicted in FIG. 6, the processing chambers 610-640 are radially disposed about a coating drum 655. Arrangements other than radial are contemplated. For example, in another implementation, the processing chambers may be positioned in a linear configuration.24SUBSTITUTE SHEET RULE 26

[0029] In one implementation, the processing chambers 610-640 are stand-alone modular processing chambers wherein each modular processing chamber is structurally separated from the other modular processing chambers. Therefore, each of the stand-alone modular processing chambers, can be arranged, rearranged, replaced, or maintained independently without affecting each other. Although four processing chambers 610-640 are shown, it should be understood that any number of processing chambers may be included in the flexible substrate coating apparatus 600.

[0030] The processing chambers 610-640 may include any suitable structure, configuration, arrangement, and / or components that enable the flexible substrate coating apparatus 600 to deposit portions of the SIDT stack according to implementations of the present disclosure. For example, but not limited to, the processing chambers may include suitable deposition systems including coating sources, power sources, individual pressure controls, deposition control systems, and temperature control. According to typical implementations, the chambers are provided with individual gas supplies. The chambers are typically separated from each other for providing a good gas separation. The flexible substrate coating apparatus 600 according to implementations described herein is not limited in the number of deposition chambers. For example, but not limited to, flexible substrate coating apparatus 600 may include 3, 6, or 12 processing chambers.

[0031] The processing chambers 610-640 typically include one or more deposition units 612, 622, 632, and 642. Generally, the one or more deposition units as described herein can be selected from the group of a CVD source, an ALD source, a PECVD source, and a PVD source. The one or more deposition units can include an evaporation source, a sputter source, such as, a magnetron sputter source, a DC sputter source, an AC sputter source, a pulsed sputter source, a radio frequency (RF) sputtering source, or a middle frequency (MF) sputtering source. The one or more deposition units can include an evaporation source. In one implementation, the evaporation source is a thermal evaporation source or an electron beam evaporation source. In one implementation, the evaporation source is a lithium (Li) source. Further, the evaporation source may also be an alloy of two or more metals. The material to be deposited (e.g., lithium) can be provided in a crucible. The lithium can,25SUBSTITUTE SHEET RULE 26for example, be evaporated by thermal evaporation techniques or by electron beam evaporation techniques.

[0032] In some implementations, one or some of the chambers may be configured for performing deposition by other methods, such as, but not limited to, chemical vapor deposition, atomic layer deposition or pulsed laser deposition. In some implementations, one or some of the chambers may be configured for performing a plasma treatment process, such as a plasma oxidation or plasma nitridation process.

[0033] In one or more implementations, the processing chambers 610-640 are configured to process both sides of the continuous sheet of material 650. Although the flexible substrate coating apparatus 600 is configured to process the continuous sheet of material 650, which is horizontally oriented, the flexible substrate coating apparatus 600 may be configured to process substrates positioned in different orientations, for example, the continuous sheet of material 650 may be vertically oriented. In one or more implementations, the continuous sheet of material 650 is a flexible support layer, for example, the flexible support layer stack 200 as described herein. In one or more implementations, the continuous sheet of material 650 includes a PET substrate and optionally a release layer.

[0034] In one or more implementations, the flexible substrate coating apparatus 600 comprises a transfer mechanism 652. The transfer mechanism 652 may include any transfer mechanism capable of moving the continuous sheet of material 650 through the processing region of the processing chambers 610-640. The transfer mechanism 652 may include a common transport architecture. The common transport architecture may include a reel-to-reel system with a common take-up reel 654 positioned in the winding module 606, the coating drum 655 positioned in the processing module 604, and a feed reel 656 positioned in the unwinding module 602. The take-up reel 654, the coating drum 655, and the feed reel 656 may be individually heated. The take-up reel 654, the coating drum 655, and the feed reel 656 may be individually heated using an internal heat source positioned within each reel or an external heat source. The common transport architecture may further comprise one or more auxiliary transfer reels 653a, 653b positioned between the take-up reel 654, the coating drum 655, and the feed reel 656. Although the flexible substrate coating apparatus 600 is depicted as having a single processing region, in one or more26SUBSTITUTE SHEET RULE 26implementations, it may be advantageous to have separated or discrete processing regions for each individual processing chamber 610-640. For implementations having discrete processing regions, modules, or chambers, the common transport architecture may be a reel-to-reel system where each chamber or processing region has an individual take-up-reel and feed reel and one or more optional intermediate transfer reels positioned between the take-up reel and the feed reel.

[0035] The flexible substrate coating apparatus 600 may include the feed reel 656 and the take-up reel 654 for moving the continuous sheet of material 650 through the different processing chambers 610-640. In one or more implementations, which can be combined with other implementations, each of the processing chamber can be configured to deposit portions of the SIDT stack 255. In one implementation, the first processing chamber 610 and the second processing chamber 620 are each configured to deposit one or more of the seed layer 220, protective layers, and / or SEI layers. The third processing chamber 630 and the fourth processing chamber 640 are configured to deposit a portion of an alkali metal-containing film, for example, the lithium metal layer 250.

[0036] In one implementation, processing chambers 630 and 640 are configured for depositing a thin film of lithium metal on the continuous sheet of material 650. Any suitable lithium deposition process for depositing thin films of lithium metal may be used to deposit the thin film of lithium metal. Deposition of the thin film of lithium metal may be by PVD processes, such as evaporation. The chambers for depositing the thin film of lithium metal may include a PVD system, such as an electron-beam evaporator, a thermal evaporator, or a lamination system.

[0037] In operation, the continuous sheet of material 650 is unwound from the feed reel 656 as indicated by the substrate movement direction shown by arrow 608. The continuous sheet of material 650 may be guided via one or more auxiliary transfer reels 653a, 653b. It is also possible that the continuous sheet of material 650 is guided by one or more substrate guide control units (not shown) that shall control the proper run of the flexible substrate, for instance, by fine adjusting the orientation of the flexible substrate.

[0038] After uncoiling from the feed reel 656 and running over the auxiliary transfer reel 653a, the continuous sheet of material 650 is then moved through the deposition27SUBSTITUTE SHEET RULE 26areas provided at the coating drum 655 and corresponding to positions of the deposition units 612, 622, 632, and 642. During operation, the coating drum 655 rotates around axis 651 such that the flexible substrate moves in the direction of arrow 608.

[0039] Figure 7 illustrates a schematic side view of a lamination transfer system 700 in accordance with one or more implementations of the present disclosure. The lamination transfer system 700 includes equipment for transferring SIDT stacks, for example, the SIDT stacks 255, including lithium metal layers on a flexible support layer 710, for example, the flexible support layer stack 200, and a second flexible support layer 720, for example the flexible support layer stack 200, to each side of a flexible receiving substrate 730, for example, the receiving substrate 260, so that the receiving substrate 260 with the lithium metal layer 250 can be used as an electrode (e.g., anode) or a pre-lithiated electrode in a lithium-ion battery. The lamination transfer system 700 may include a pre-heating unit (not shown) for pre-heating the SIDT stacks 255 on the flexible support layers 710, 720 prior to transfer to the flexible receiving substrate 730. The lamination transfer system 700 can further include a calendering unit 740 to transfer the SIDT stacks 255 on the flexible support layers 710, 720 to the flexible receiving substrate 730.

[0040] The lamination transfer system 700 includes a first flexible support layer supply hub 715. A supply roll 711 of the first flexible support layer 710 is positioned on the first flexible support layer supply hub 715. In some implementations, the first flexible support layer 710 can be formed of a polymer material, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), metallized plastic, or combinations thereof. A SIDT stack including a lithium metal layer (not shown in Figure 7) is positioned on the lower side 710L of the first flexible support layer 710, so that this lithium metal layer faces an upper surface 730U of the flexible receiving substrate 730 as the first flexible support layer 710 and the flexible receiving substrate 730 are conveyed through the calendering unit 740. The upper surface 730U of the flexible receiving substrate 730 is on an opposite side relative to a lower surface 730L of the flexible receiving substrate 730. The upper surface 730U is also referred to as the first surface or the first side of the flexible receiving substrate 730 while the lower surface is also referred to as the second surface or the second side of the flexible receiving substrate 730.28SUBSTITUTE SHEET RULE 26

[0041] The lamination transfer system 700 includes a second flexible support layer supply hub 725. A supply roll 721 of the second flexible support layer 720 is positioned on the second flexible support layer supply hub 725. In some implementations, the second flexible support layer 720 can be formed of a same material (e.g., PET) as the first flexible support layer 710. A SIDT stack including a lithium metal layer (not shown in Figure 7), for example, any of the SIDT stack 255 is positioned on the upper side 720U of the second flexible support layer 720, so that this lithium metal layer faces the lower surface 730L of the flexible receiving substrate 730 as the second flexible support layer 720 and the flexible receiving substrate 730 are conveyed through the calendering unit 740.

[0042] The lamination transfer system 700 includes a flexible substrate supply hub 735. A supply roll 731 of the flexible receiving substrate 730 is positioned on the flexible substrate supply hub 735. In some implementations, the flexible receiving substrate 730 can be formed of one or more of copper, graphite, silicon, silicon graphite, silicon oxide graphite, silicon, metalized plastic, or other materials.

[0043] The lamination transfer system 700 further includes the calendering unit 740. The calendering unit 740 includes a first calender roller 741 and a second calender roller 742. The first flexible support layer 710, the second flexible support layer 720, and the flexible receiving substrate 730 are arranged to be conveyed along a path that extends between the first calender roller 741 and the second calender roller 742. The flexible receiving substrate 730 is positioned between the first flexible support layer 710 and the second flexible support layer 720 when the first flexible support layer 710, the second flexible support layer 720, and the flexible receiving substrate 730 are conveyed between the first calender roller 741 and the second calender roller 742. The calender rollers 741 , 742 exert a high amount of pressure on the flexible support layers 710, 720 and the flexible receiving substrate 730 that causes the SIDT stack 255 including the lithium metal layer 250 and at least a portion of the seed layer 220 formed on each of the flexible support layers 710, 720 to be transferred to the flexible receiving substrate 730.

[0044] The lamination transfer system 700 includes a first flexible support layer pickup hub 716. A pickup roll 712 of the first flexible support layer 710 is positioned on the first flexible support layer pickup hub 716. The SIDT stack 255 is no longer on29SUBSTITUTE SHEET RULE 26the first flexible support layer 710 when the first flexible support layer 710 is wound onto the first flexible support layer pickup hub 716 because the SIDT stack 255 previously on the first flexible support layer 710 is transferred onto the flexible receiving substrate 730 by the calendering unit 740.

[0045] The lamination transfer system 700 includes a second flexible support layer pickup hub 726. A pickup roll 722 of the second flexible support layer 720 is positioned on the second flexible support layer pickup hub 726. The SIDT stack 255 is no longer on the second flexible support layer 720 when the second flexible support layer 720 is wound onto the second flexible support layer pickup hub 726 because the SIDT stack 255 previously on the second flexible support layer 720 is transferred onto the flexible receiving substrate 730 by the calendering unit 740.

[0046] The lamination transfer system 700 includes a flexible substrate pickup hub 736. A pickup roll 732 of the flexible receiving substrate 730 is positioned on the flexible substrate pickup hub 736. The flexible receiving substrate 730 includes a SIDT stack on each of the upper surface 730U and the lower surface 730L of the flexible receiving substrate 730. The SIDT stacks are transferred from the respective flexible support layers 710, 720 onto the flexible receiving substrate 730 by the calendering unit 740.

[0047] The lamination transfer system 700 further includes a plurality of rollers 781 - 788. In some implementations, each of the rollers 781 -788 can be passive rollers. The rollers 781 -788 can assist in applying proper tension to and assist in changing the direction of the flexible support layers 710, 720 and the flexible receiving substrate 730 during the movement of each of the flexible support layers 710, 720 and the flexible receiving substrate 730 through the different portions of the lamination transfer system 700. Some of the rollers 781 -788 can also assist in moving the flexible support layers 710, 720 closer to or further away from the flexible receiving substrate 730. For example, the second and third rollers 782, 783 assist in bringing the flexible support layers 710, 720 into contact with the flexible receiving substrate 730 before the flexible support layers 710, 720 and the flexible receiving substrate 730 are conveyed through the calendering unit 740. Additionally, the fourth and fifth rollers 784, 785 provide a location at which tension can be applied to the flexible support layers 710, 720 to peel the flexible support layers 710, 720 away from the flexible receiving substrate 730.30SUBSTITUTE SHEET RULE 26Upon separating the flexible support layers 710, 720 from the flexible receiving substrate 730, sixth and seventh rollers 786, 787 in turn route the flexible support layers 710, 720 toward the corresponding flexible support layer pickup hubs 716, 726 which may be used for re-capturing or reclaiming the flexible support layers 710, 720. In some implementations, one or more of the rollers 781 -788 can instead be a bar, such as metal bar, that can apply tension during the movement of the flexible support layer or flexible substrate.

[0048] The lamination transfer system 700 can further include actuators (not shown) configured to rotate each of the hubs 715, 716, 725, 726, 735, 736, so that the flexible support layers 710, 720 and the flexible receiving substrate 730 can be conveyed from the corresponding supply hub 715, 725, 735, through the calendering unit 740, and to the corresponding pickup hubs 716, 726, 736. The lamination transfer system 700 can further include one or more actuators (not shown) to rotate the calender rollers 741 , 742 of the calendering unit 740. The rotational speed of the actuators can be adjusted to control the speed at which the flexible receiving substrate 730 and flexible support layers 710, 720 are conveyed through the lamination transfer system 700.

[0049] In the lamination transfer system 700, the flexible receiving substrate 730 is conveyed along a path from the supply roll 731 that is supported by the supply hub 735, past the first roller 781 , between the second and third rollers 782, 783, between the calender rollers 741 , 742, between the fourth and fifth rollers 784, 785, past the eighth roller 788, and to the pickup roll 732 around the pickup hub 736. The pickup hub 736 is configured to rotate and assist in conveying the flexible substrate along the path after the flexible receiving substrate 730 passes between the first calender roller 741 and the second calender roller 742. Similarly, the pickup hubs 716, 726 are configured to rotate and assist in conveying the flexible support layers along paths between the first and second supply hubs 715, 725 and the first and second support layer pickup hubs 716, 726.

[0050] The lamination transfer system 700 can also include a controller 705 for controlling processes performed by the lamination transfer system 700. The controller 705 can be any type of controller used in an industrial setting, such as a programmable logic controller (PLC). The controller 705 includes a processor 707, a memory 706,31SUBSTITUTE SHEET RULE 26and input / output (I / O) circuits 708. The controller 705 can further include one or more of the following components (not shown), such as one or more power supplies, clocks, communication components (e.g., network interface card), and user interfaces typically found in controllers for semiconductor equipment.

[0051] The memory 706 can include non-transitory memory. The non-transitory memory can be used to store the programs and settings described below. The memory 706 can include one or more readily available types of memory, such as read only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM).

[0052] The processor 707 is configured to execute various programs stored in the memory 706, such as a program configured to execute the methods 100 and 300 described herein. During execution of these programs, the controller 705 can communicate to I / O devices through the I / O circuits 708. For example, during execution of these programs and communication through the I / O circuits 708, the controller 705 can control outputs (e.g., the actuators connected to the different hubs and the calendering unit 740). The memory 706 can further include various operational settings used to control the lamination transfer system 700. For example, the settings can include speed settings for the actuators connected to the hubs.

[0053] In summation, the present disclosure provides a method of transferring a lithium metal layer using a seed layer formed on a flexible support layer as a release layer for transferring to a receiving substrate. Use of the seed layer provides control over the thickness, chemistry, quality, and release pressure of the release layer needed for separating the lithium metal layer from the flexible support layer. Upon separating the lithium metal layers from the flexible support layer, at least a portion of the seed layer is also transferred to the receiving substrate to act as a surface passivation layer for the lithium metal layers transferred to the receiving substrate. Use of the seed layer may therefore provide a simple, effective, and controllable method for achieving high-performance lithium transfer processes for forming anode film stacks or pre-l ith iat ion . The anode film stack formed can act as an anode structure for an energy storage device. In addition to also acting as a surface passivation layer32SUBSTITUTE SHEET RULE 26for the transferred lithium metal layers, the seed layer described herein may be configured and engineered to keep the impedance between the anode structure formed and separator interface low, such as less than about 200 ohms / cm2The materials of the seed layer may also be tailored and selected for cost effectiveness and the chemistries of the flexible support layer and / or the specific battery chemistries and applications thereof the lithium metal layer is intended to be used with.

[0054] While the foregoing is directed to implementations of the present disclosure, other and further implementations of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.33SUBSTITUTE SHEET RULE 26

Claims

What is claimed is:1 . A method for transferring a lithium metal layer, comprising: forming a seed layer over a flexible support layer; depositing a lithium metal layer on the seed layer; laminating the lithium metal layer to a flexible receiving substrate; and separating the lithium metal layer from the flexible support layer to transfer the lithium metal layer to the receiving substrate, wherein at least a portion of the seed layer is transferred with the lithium metal layer to the receiving substrate to provide the lithium metal layer with passivation.

2. The method of claim 1 , wherein the seed layer is formed on the flexible support layer by sputtering, reactive sputtering, evaporation, PVD, CVD, PECVD or other vapor deposition processes.

3. The method of claim 1 , wherein the seed layer and the lithium metal layer are both formed in a vacuum environment without breaking vacuum.

4. The method of claim 1 , wherein the flexible support layer comprises polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose tri-acetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof.

5. The method of claim 1 , wherein the seed layer comprises Li F, Li2CO3, Ag, Bi, Sn, Ag+LiF, Bi+LiF, Sn+LiF, AgF, CxFy, or a combination thereof.

6. The method of claim 1 , wherein the seed layer has a thickness between about 1 nm and about 5,000 nm.

7. The method of claim 1 , wherein the portion of the seed layer transferred to the receiving substrate acts as a surface passivation layer for the lithium metal layer.

8. The method of claim 1 , wherein transferring the lithium metal layer comprises applying a release pressure between about .3 gram force / cm2 and about 16 gram force / cm2 to separate the flexible support layer from the lithium metal layer.34SUBSTITUTE SHEET RULE 269. The method of claim 1 , wherein the seed layer comprises a plurality of sublayers, and transferring the lithium metal layer from the flexible support layer comprises separating the sub-layers of the seed layer.

10. The method of claim 1 , wherein the receiving substrate comprises one or more current collectors made of aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, alloys thereof, or a combination thereof.

11. A method for forming a film stack for an energy storage device, comprising: disposing a flexible support layer in a vacuum environment; forming a seed layer over the flexible support layer, the seed layer comprising LiF, Li2CO3, Ag, Bi, Sn, Ag+LiF, Bi+LiF, Sn+LiF, AgF, CxFy, or a combination thereof; depositing a lithium metal layer on the seed layer, the seed layer for releasing the lithium metal layer from the flexible support layer; laminating the lithium metal layer to a flexible receiving substrate, the flexible receiving comprising one or more current collectors made of aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, alloys thereof, or a combination thereof; and transferring the lithium metal layer from the flexible support layer to the flexible receiving substrate to form the film stack, wherein at least a portion of the seed layer is transferred with the lithium metal layer to the flexible receiving substrate.

12. The method of claim 11 , wherein the flexible support layer comprises polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose tri-acetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof.

13. The method of claim 11 , wherein the seed layer has a thickness between about 1 nm and about 5,000 nm.

14. The method of claim 11 , further comprising pre-heating the lithium layer and the seed layer on the flexible support layer to a temperature between about 3035SUBSTITUTE SHEET RULE 26degrees Celsius and about 200 degrees Celsius before laminating the lithium metal layer to the flexible receiving substrate.

15. A film stack for an energy storage device, comprising: a flexible receiving substrate; a lithium metal layer disposed on the flexible receiving substrate; and a seed layer disposed over at least a portion of the lithium metal layer, the seed layer for providing the portion of the lithium metal layer disposed between the seed layer and the flexible receiving substrate with passivation, wherein the lithium metal layer and the seed layer are transferred to the flexible receiving substrate from a flexible support layer with the seed layer acting as a release layer for separating the lithium metal layer from the flexible support layer.

16. The film stack of claim 20, wherein the seed layer comprises LiF, Li2CO3, Ag, Bi, Sn, Ag+LiF, Bi+LiF, Sn+LiF, AgF, CxFy, or a combination thereof.

17. The film stack of claim 15, wherein the seed layer has a thickness between about 1 nm and about 5,000 nm.

18. The film stack of claim 15, wherein the seed layer acts as a surface passivation layer for the lithium metal layer.

19. The film stack of claim 15, wherein an impedance of the film stack is less than about 200 ohms / cm2.

20. The film stack of claim 15, wherein the flexible receiving substrate comprises one or more current collectors made of aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, clad materials, alloys thereof, or a combination thereof.36SUBSTITUTE SHEET RULE 26

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