Anodes for lithium-based energy storage devices, and methods for making the same

Abstract

SOLUTION: A method of making an anode for use in energy storage devices includes providing a current collector having an electrically conductive layer and a metal oxide layer overlaying the electrically conductive layer. A continuous porous lithium storage layer is deposited on the metal oxide layer by a CVD process. The anode is thermally treated after deposition of the continuous porous lithium storage layer is complete and prior to battery assembly. The thermal treatment includes heating the anode to a temperature in the range from 100°C to 600°C for a time period in the range from 0.1 minute to 120 minutes. The anode may be incorporated into a lithium ion battery along with a cathode. The cathode may include sulfur or selenium. An anode having at least two auxiliary layers is also described. A method for producing a prelithiated anode intended for use in a lithium-ion battery is contemplated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 886,177, filed August 13, 2019, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present disclosure relates to lithium-ion batteries and related energy storage devices. [Background technology]

[0003] Silicon has been proposed as a potential material for lithium-ion batteries to replace conventional carbon-based anodes, which have a limited storage capacity of approximately 370 mAh / g. Silicon readily alloys with lithium and has a much higher theoretical storage capacity (approximately 3600 to 4200 mAh / g at room temperature) than carbon-based anodes. However, the insertion and extraction of lithium into the silicon matrix causes significant volume expansion (>300%) and contraction. This can lead to rapid shattering of the silicon into small particles and electrical disconnection from the current collector.

[0004] The industry has recently turned to nanostructured or microstructured silicon, i.e., silicon in the form of spaced apart nanowires or microwires, tubes, pillars, particles, etc., to reduce the shattering problem. The theory is that making the structures nano-sized avoids crack propagation and spacing them apart allows more space for volume expansion, thereby allowing the silicon to absorb lithium with reduced stress and improved stability compared to, for example, a macroscopic layer of bulk silicon.

[0005] Despite research into structured silicon approaches, such batteries based solely on silicon have yet to achieve significant market impact due to unresolved issues. A key issue is the manufacturing complexity and investment required to form these anodes. For example, U.S. Patent Application Publication No. 20150325852 describes silicon fabricated by first growing a silicon-based non-conformal porous layer on a nanowire template by plasma-enhanced chemical vapor deposition (PECVD), followed by deposition of a denser conformal silicon layer using thermal chemical vapor deposition (CVD). The formation of silicon nanowires can be highly sensitive to small perturbations in deposition conditions, making quality control and reproducibility challenging. Other methods for forming nanostructured or microstructured silicon involve etching silicon wafers, which is time-consuming and wasteful. Furthermore, the connection between the silicon wire and the current collector is inherently fragile, and the structure is prone to breakage or wear when subjected to the stresses of handling required to fabricate batteries. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 20150325852 Summary of the Invention

[0007] There remains a need for anodes for lithium-based energy storage devices, such as Li-ion batteries, that are easy to manufacture, durable to handle, have high charge capacity, and are suitable for fast charging, e.g., at least 1 C. These and other needs are addressed by the embodiments described herein.

[0008] According to one embodiment of the present disclosure, a method for fabricating an anode for use in an energy storage device includes providing a current collector having a conductive layer and a metal oxide layer covering the conductive layer. The metal oxide layer has an average thickness of at least 0.01 μm. A continuous porous lithium storage layer is deposited on the metal oxide layer by a CVD process. The anode is heat-treated after deposition of the continuous porous lithium storage layer is complete and before assembly into a battery. The heat treatment includes heating the anode to a temperature ranging from 100°C to 600°C for a time ranging from 0.1 minutes to 120 minutes. The anode may be incorporated into a lithium-ion battery along with a cathode. The cathode may include sulfur or selenium, and the anode may be prelithiated.

[0009] According to one embodiment of the present disclosure, an anode for an energy storage device is provided, which includes a current collector having a metal oxide layer. A continuous porous lithium storage layer covers the metal oxide layer, and a first auxiliary layer covers the continuous porous lithium storage layer. The first auxiliary layer includes silicon nitride, silicon dioxide, or silicon oxynitride.

[0010] Another embodiment of the present disclosure provides an anode for an energy storage device, including a current collector having a metal oxide layer, a continuous porous lithium storage layer covering the metal oxide layer, a first auxiliary layer covering the continuous porous lithium storage layer, and a second auxiliary layer covering the first auxiliary layer. The first auxiliary layer includes silicon nitride, silicon dioxide, silicon oxynitride, or a first metal compound. The second auxiliary layer has a composition different from that of the first auxiliary layer and includes silicon dioxide, silicon nitride, silicon oxynitride, or a second metal compound. One of the first auxiliary layer or the second auxiliary layer includes titanium dioxide and has a thickness ranging from about 2 nm to about 50 nm.

[0011] According to another embodiment of the present disclosure, a method for making a prelithiated anode for use in a lithium-ion battery includes providing a current collector having a conductive layer and a metal oxide layer covering the conductive layer. The metal oxide layer has an average thickness of at least 0.01 μm. A continuous porous lithium storage layer is deposited on the metal oxide layer by a CVD process. Lithium is incorporated into the continuous porous lithium storage layer to form a lithiated storage layer prior to the first electrochemical cycle when the anode is assembled into a battery. The anode may be incorporated into a lithium-ion battery with a cathode. The cathode may include sulfur or selenium, and the anode may be prelithiated.

[0012] The present disclosure provides anodes for energy storage devices that can have one or more of at least the following advantages compared to conventional anodes: improved stability at rapid charge rates ≧1 C; higher all-surface charge capacity; higher charge capacity per gram of silicon; improved physical durability; simplified manufacturing process; and more reproducible manufacturing process. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 2] FIG. 1 is a cross-sectional view of a prior art anode. [Figure 3] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 4] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 5] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 6] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 7A] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 7B] 1 is a cross-sectional view of an anode according to some embodiments of the present disclosure. [Figure 8] FIG. 1 is a process flow diagram for preparing an anode according to certain embodiments of the present disclosure. [Figure 9A] FIG. 1 is a schematic diagram of an apparatus for roll-to-roll processing of anodes according to some embodiments of the present disclosure. [Figure 9B] FIG. 1 is a schematic diagram of an apparatus for roll-to-roll processing of anodes according to some embodiments of the present disclosure. [Figure 10] FIG. 1 is a cross-sectional view of a battery according to some embodiments of the present disclosure. [Figure 11] FIG. 10 shows cycling performance data for anodes according to some embodiments of the present disclosure. [Figure 12] FIG. 10 shows cycling performance data for anodes according to some embodiments of the present disclosure. [Figure 13] FIG. 10 shows cycling performance data for anodes according to some embodiments of the present disclosure. [Figure 14] FIG. 10 shows cycling performance data for anodes according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] It should be understood that the drawings are for purposes of illustrating the concepts of the disclosure and may not be to scale.

[0015] Anode Overview FIG. 1 is a cross-sectional view according to some embodiments of the present disclosure. Anode 100 includes a conductive current collector 101 and a continuous porous lithium storage layer 107. In this embodiment, conductive current collector 101 includes a metal oxide layer 105 disposed on a conductive layer 103, such as a conductive metal layer. Continuous porous lithium storage layer 107 is disposed on metal oxide layer 105. In some embodiments, the top of continuous porous lithium storage layer 107 corresponds to top surface 108 of anode 100. In some embodiments, continuous porous lithium storage layer 107 is in physical contact with the metal oxide layer. In some embodiments, the active material of the continuous porous lithium storage layer may partially extend into the metal oxide layer. In some embodiments, the continuous porous lithium storage layer includes a material capable of forming an electrochemically reversible alloy with lithium. In some embodiments, the continuous porous lithium storage layer includes silicon, germanium, tin, or an alloy thereof. In some embodiments, the continuous porous lithium storage layer includes at least 40 atomic % silicon, germanium, or a combination thereof. In some embodiments, the continuous porous lithium storage layer is provided by a chemical vapor deposition (CVD) process, including but not limited to hot wire CVD or plasma enhanced chemical vapor deposition (PECVD). In some embodiments, the CVD storage layer deposition process can reduce a portion of the metal oxide layer to metal.

[0016] In the present disclosure, the continuous porous lithium storage layer is substantially free of nanostructures, for example, in the form of spaced wires, pillars, tubes, or regular linear vertical channels extending through the lithium storage layer. Figure 2 shows a cross-sectional view of a prior art anode 170 including some non-limiting examples of nanostructures, such as nanowires 190, nanopillars 192, nanotubes 194, and nanochannels 196, disposed on a current collector 180. The term "nanostructure" herein generally refers to an active material structure (e.g., a structure of silicon, germanium, or alloys thereof) having at least one cross-sectional dimension less than about 2,000 nm, excluding dimensions generally perpendicular to the underlying substrate (e.g., layer thickness) and excluding dimensions caused by random pores and channels. Similarly, the terms "nanowire," "nanopillar," and "nanotube" refer to wires, pillars, and tubes, respectively, at least a portion of which has a diameter less than 2,000 nm. "High aspect ratio" nanostructures have an aspect ratio greater than 4:1, where the aspect ratio is generally the height or length of the feature (which may be measured along a feature axis aligned at an angle of 45 to 90 degrees relative to the underlying current collector surface) divided by the width of the feature (which may be measured approximately perpendicular to the feature axis). In some embodiments, a continuous porous lithium storage layer is considered "substantially free" of nanostructures if the anode has an average of fewer than 10 nanostructures per 1600 square microns (the number of nanostructures being the sum of the number of nanowires, nanopillars, and nanotubes in the same unit area, such as nanostructures with an aspect ratio of 4:1 or greater). Alternatively, there is an average of less than one such nanostructure per 1600 square micrometers. As discussed below, the current collector can have high surface roughness or the surface layer can include nanostructures, but these features are distinct from the continuous porous lithium storage layer.

[0017] In some embodiments, deposition conditions are selected in combination with the metal oxide such that the continuous, porous lithium storage layer is relatively smooth and provides an anode having a diffuse or total reflectance at 550 nm of at least 10%, or alternatively at least 20% (measured on the continuous, porous lithium storage layer side). In some embodiments, the anode can have a lower reflectance than those cited above, for example, by providing a current collector with a rough surface or by modifying the deposition conditions of the lithium storage layer.

[0018] The anode may be a continuous foil or sheet, but may alternatively be a mesh or have some other three-dimensional structure. In some embodiments, the anode is flexible.

[0019] 3, current collector 301 includes conductive layer 303 and metal oxide layers (305a, 305b) deposited on either side of conductive layer 303, with continuous porous lithium storage layers (307a, 307b) disposed on either side to form anode 300. Metal oxide layers 305a and 305b may be the same or different in terms of composition, thickness, porosity, or some other property. Similarly, continuous porous lithium storage layers 307a and 307b may be the same or different in terms of composition, thickness, porosity, or some other property.

[0020] In some embodiments, the current collector has a mesh structure, a representative cross section of which is shown in Figure 4. Current collector 401 includes a metal oxide layer 405 substantially surrounding an inner conductive core 403, e.g., a wire forming part of the mesh, with the core acting as the conductive layer. A continuous porous lithium storage layer 407 is provided on top of the metal oxide layer to form anode 400. The mesh can be formed from interwoven wires or ribbons of metal or conductive carbon and can be formed by patterning holes in a substrate, e.g., a metal or metal-coated sheet, or by any suitable method known in the art.

[0021] current collector The current collector (101, 301, 401) includes at least one metal oxide layer (105, 305, 405) and may further include a separate conductive layer (103, 303, 403). The metal oxide can be stoichiometric or non-stoichiometric. The metal oxide layer can include a mixture of metal oxides, a mixture of metals, or both, with uniform or non-uniformly distributed oxide stoichiometry. The separate conductive layer (103, 303, 403) is optional if the metal oxide layer (105, 305, 405) is sufficiently conductive to function as a current collector. In embodiments using a conductive layer, the metal oxide layer should be sufficiently conductive (e.g., at least semiconductive or non-insulating) to allow charge transfer between the conductive layer and the continuous porous lithium storage layer. The metal oxide layer may include dopants or regions of unoxidized metal that promote conductivity. In some embodiments, the conductive layer has a conductivity of at least 10 3 S / m, or at least 10 6 S / m, or at least 10 7 The material may have a conductivity of 0.05 S / m and may comprise inorganic or organic conductive materials or a combination thereof.

[0022] In some embodiments, the conductive layer comprises a metallic material, such as titanium (and its alloys), nickel (and its alloys), copper (and its alloys), or stainless steel. In some embodiments, the conductive layer comprises a conductive carbon, such as carbon black, carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, and graphite. In some embodiments, the conductive layer may be in the form of a foil or sheet of conductive material, or a layer deposited on an insulating substrate (e.g., a polymer sheet optionally coated on both sides with a conductive material such as nickel or copper).

[0023] In some embodiments, the metal oxide layer comprises a transition metal oxide, such as an oxide of nickel, titanium, or copper. In some embodiments, the metal oxide layer comprises an oxide of aluminum. In some embodiments, the metal oxide layer is a conductive doped oxide, including, but not limited to, indium-doped tin oxide (ITO) or aluminum-doped zinc oxide (AZO). In some embodiments, the metal oxide layer comprises an alkali metal oxide or an alkaline earth metal oxide. In some embodiments, the metal oxide layer comprises an oxide of lithium. As described above, the metal oxide layer may comprise a mixture of metals. For example, "nickel oxide" may optionally include other metals in addition to nickel. In some embodiments, the metal oxide layer comprises an oxide of an alkali metal or alkaline earth metal (e.g., lithium or sodium) along with an oxide of a transition metal (e.g., nickel or copper). In some embodiments, the metal oxide layer may contain a small amount of hydroxide, such that the ratio of oxygen atoms in the form of hydroxide to oxide is less than 0.25, respectively.

[0024] In some embodiments, the metal oxide layer has an average thickness of at least 0.005 μm, alternatively at least 0.01 μm, alternatively at least 0.02 μm, alternatively at least 0.05 μm, alternatively 0.1 μm, alternatively at least 0.2 μm, alternatively at least 0.5 μm. In some embodiments, the metal oxide layer has an average thickness ranging from about 0.005 μm to about 0.01 μm, alternatively from about 0.01 μm to about 0.02 μm, alternatively from about 0.02 μm to about 0.05 μm, alternatively from about 0.05 μm to about 0.1 μm, alternatively from about 0.1 μm to about 0.2 μm, alternatively from about 0.2 μm to about 0.5 μm, alternatively from about 0.5 μm to about 1 μm, alternatively from about 1 μm to about 2 μm, alternatively from about 2 μm to about 5 μm, alternatively from about 5 μm to about 1 μm, or any combination of contiguous ranges thereof.

[0025] The metal oxide layer can include a stoichiometric oxide, a non-stoichiometric oxide, or both. In some embodiments, the metal within the metal oxide layer can exist in multiple oxidation states. In some embodiments, the metal oxide layer can have an oxygen content gradient, where the atomic % of oxygen adjacent to the conductive layer is lower than the atomic % adjacent to the lithium storage layer.

[0026] In some embodiments, the metal oxide layer is formed directly by atomic layer deposition (ALD), CVD, evaporation, or sputtering. In some embodiments, the conductive layer is a metal layer 103, and the metal oxide layer is formed by oxidizing a portion of the conductive (metal) layer. For example, a metal can be thermally oxidized in the presence of oxygen, electrolytically oxidized, or chemically oxidized in an oxidizing liquid or gas medium to form a metal oxide layer.

[0027] In some embodiments, a metal oxide layer precursor composition can be coated or printed onto the conductive layer 103 and then processed to form the metal oxide layer 105. Some non-limiting examples of metal oxide precursor compositions include sol-gels (metal alkoxides), metal carbonates, metal acetates (including organic acetates), metal hydroxides, and metal oxide dispersions. The metal oxide precursor composition can be heat-treated to form the metal oxide layer. In some embodiments, room temperature can be a sufficient temperature to heat-treat the precursor. In some embodiments, the metal oxide precursor composition is heat-treated by exposure to a temperature of at least 50°C, alternatively in the range of 50°C to 150°C, alternatively in the range of 150°C to 250°C, alternatively in the range of 250°C to 350°C, alternatively in the range of 350°C to 450°C, or any combination of these ranges. The heat treatment time for forming a metal oxide layer from the precursor depends on many factors, but may range from about 0.1 minute to about 1 minute, alternatively from about 1 minute to about 5 minutes, alternatively from about 5 minutes to about 10 minutes, alternatively from about 10 minutes to about 30 minutes, alternatively from about 30 minutes to about 60 minutes, alternatively from about 60 minutes to about 90 minutes, alternatively from about 90 minutes to about 120 minutes, or any combination of consecutive ranges thereof. In some embodiments, the heat treatment may be carried out using an oven, an infrared heating element, contact with a heated surface (e.g., a hot plate), or exposure to a flash lamp. In some embodiments, the metal oxide precursor composition is treated to form the metal oxide by exposing it to a reduced pressure, e.g., to drive off solvents or volatile reaction products. The reduced pressure may be less than 100 Torr, alternatively from 0.1 to 100 Torr. The exposure time to reduced pressure can range from about 0.1 minutes to about 1 minute, alternatively from about 1 minute to about 5 minutes, alternatively from about 5 minutes to about 10 minutes, alternatively from about 10 minutes to about 30 minutes, alternatively from about 30 minutes to about 60 minutes, alternatively from about 60 minutes to about 90 minutes, alternatively from about 90 minutes to about 120 minutes, or any combination of consecutive ranges thereof. In some embodiments, both reduced pressure and heat treatment can be used.

[0028] In some embodiments, the metal oxide layer precursor composition comprises a metal, e.g., a metal-containing particle, that is treated with an oxidizing agent (e.g., as described above) under conditions that readily oxidize the oxide layer precursor but do not significantly oxidize the underlying conductive layer. The metal oxide precursor composition may comprise a metal that is the same as or different from the metal of the conductive layer. In some embodiments, multiple metal precursor compositions can be used to form patterns of different metal oxides or multilayer structures of different metal oxides.

[0029] In some embodiments, the conductive layer comprises a mesh or sheet of conductive carbon, including, but not limited to, those formed from bundled carbon nanotubes or nanofibers. In some embodiments, such carbon-based conductive layers can include a surface layer of a conductive metal, such as nickel, copper, zinc, or titanium. In some embodiments, the conductive metal surface layer can be applied by electrolytic or electroless plating. The metal surface layer can be partially or fully oxidized to form a corresponding metal oxide layer. In some embodiments, the porous metal oxide can have a density lower than that of the non-porous metal oxide. In some embodiments, the density of the porous metal oxide is in the range of 50% to 60%, alternatively 60% to 70%, alternatively 70% to 80%, alternatively 80% to 90%, alternatively 90% to 95%, alternatively 95% to 99% of the density of the non-porous metal oxide, or any combination of consecutive ranges thereof.

[0030] In some embodiments, the metal oxide is formed in or along the same chamber as the tool used to deposit the continuous, porous lithium storage layer. The doped metal oxide layer can be formed by adding a dopant or dopant precursor during the metal oxide formation step, or alternatively, by adding a dopant or dopant precursor to the surface of the conductive layer before the metal oxide layer formation step, or alternatively, by treating the metal oxide layer with a dopant or dopant precursor after the initial formation of the metal oxide layer. In some embodiments, the metal oxide layer itself can have some reversible or irreversible lithium storage capacity. In some embodiments, the reversible capacity of the metal oxide layer is lower than that of the continuous, porous lithium storage layer. In some embodiments, the metal oxide layer can be porous.

[0031] In some embodiments, the metal oxide may be provided in a pattern on the conductive layer, as disclosed in U.S. Patent Application No. 16 / 909,008, the entire contents of which are incorporated herein for all purposes.

[0032] In some embodiments, the metal oxide is formed by oxidizing the surface region of a metal substrate, e.g., by oxidizing a metal foil, such as nickel foil. The unoxidized portion of the metal foil acts as a conductive layer, while the oxidized portion corresponds to the metal oxide layer. This method is suitable for high-volume, low-cost production of current collectors. The oxidation conditions depend on the metal / metal surface, the target oxide thickness, and the desired oxide porosity. Unless otherwise specified, any reference to a specific metal includes alloys of that metal. For example, nickel foil can include pure nickel or any nickel alloy in which nickel is the primary component. In some embodiments, the alloy metal also oxidizes, and the nickel oxide formed from the alloy can include the corresponding metal oxide. In some embodiments, the current collector is formed by oxidizing a nickel substrate, e.g., nickel foil, in an air furnace at a temperature of at least 300°C, or at least 400°C, e.g., in the range of about 600°C to about 900°C, or higher. The hold time depends on the selected temperature and the desired thickness / porosity of the metal oxide layer. Typically, the oxidation hold time ranges from about 1 minute to about 2 hours, although shorter or longer times are contemplated. A surface pretreatment step can be applied to promote or control oxidation. Other metals, such as copper and titanium, may have other run hold times, temperatures, and pretreatments depending on their tendency to oxidize.

[0033] A current collector may have a conductive layer that includes two or more sublayers with different chemical compositions. For example, a current collector may include a metallic copper foil as a first conductive sublayer, a metallic nickel second conductive sublayer on the copper, and a layer of nickel oxide on the metallic nickel. As previously mentioned, the metallic copper and nickel may be in the form of an alloy. Similarly, a metal oxide layer may include two or more sublayers with different chemical compositions. For example, a current collector may include a metallic copper foil, a layer of copper oxide on the copper foil, and a layer of titanium dioxide on the copper oxide. Figure 5 shows a cross-sectional view of these embodiments. The anode 500 in Figure 5 includes a conductive current collector 501 having a metal oxide layer 505 on a conductive layer 503. The conductive layer 503 is divided into first and second conductive sublayers 503a and 503b, respectively, and the metal oxide layer 505 is divided into first and second metal oxide sublayers 505a and 505b, respectively. Formed on top of the second metal oxide sublayer 505b is a continuous porous lithium storage layer 507. Such a sublayer may be discontinuous or may take the form of a chemical composition gradient. In some embodiments, a gradient or transition region may exist between the conductive layer and the metal oxide layer.

[0034] In some embodiments (not shown), the conductive current collector precursor may initially have a conductive layer with a metal sublayer, such that the second metal sublayer on the surface is more easily oxidized than the underlying first metal sublayer. Under the oxidizing conditions used to form the current collector, only the second sublayer oxidizes (either in whole or in part). This allows for better control of the thickness of the metal oxide layer.

[0035] Continuous porous lithium storage layer The continuous porous lithium storage layer comprises a porous material capable of reversibly incorporating lithium. In some embodiments, the continuous porous lithium storage layer comprises silicon, germanium, or a mixture of both. In some embodiments, the continuous porous lithium storage layer comprises antimony or tin. In some embodiments, the continuous porous lithium storage layer is substantially amorphous. In some embodiments, the continuous porous lithium storage layer comprises substantially amorphous silicon. Such a substantially amorphous storage layer may contain a small amount (e.g., less than 20 atomic %) of crystalline material dispersed therein. The continuous porous lithium storage layer may also include dopants such as hydrogen, boron, phosphorus, sulfur, fluorine, aluminum, gallium, indium, arsenic, antimony, bismuth, nitrogen, or metallic elements. In some embodiments, the continuous porous lithium storage layer may comprise porous, substantially amorphous hydrogenated silicon (a-Si:H) having a hydrogen content of, for example, 0.1 to 20 atomic % or more. In some embodiments, the continuous porous lithium storage layer may also include methylated amorphous silicon. It should be noted that unless hydrogen content is specifically mentioned, the atomic % metrics used herein for lithium storage materials or layers refer to all atoms other than hydrogen.

[0036] In some embodiments, the continuous porous lithium storage layer comprises at least 40 atomic % silicon, germanium, or a combination thereof, alternatively at least 50 atomic %, alternatively at least 60 atomic %, alternatively at least 70 atomic %, alternatively at least 80 atomic %, alternatively at least 90 atomic %. In some embodiments, the continuous porous lithium storage layer comprises at least 40 atomic % silicon, alternatively at least 50 atomic %, alternatively at least 60 atomic %, alternatively at least 70 atomic %, alternatively at least 80 atomic %, alternatively at least 90 atomic %, alternatively at least 95 atomic %, alternatively at least 97 atomic %.

[0037] In some embodiments, the continuous porous lithium storage layer comprises less than 10 atomic %, alternatively less than 5 atomic %, alternatively less than 2 atomic %, alternatively less than 1 atomic %, alternatively less than 0.5 atomic % carbon. In some embodiments, the continuous porous lithium storage layer comprises less than 5% by weight, alternatively less than 1% by weight, of carbon-based binders, carbon nanotubes, graphitic carbon, graphene, graphene oxide, reduced graphene oxide, carbon black, and conductive carbon.

[0038] The continuous porous lithium storage layer contains voids or gaps (pores) that can be random or non-uniform in size, shape, and distribution. Such porosity does not result in or result from the formation of any recognizable nanostructures, such as nanowires, nanopillars, nanotubes, or nanochannels. In some embodiments, the pores are polydisperse. In some embodiments, when analyzed by SEM cross section, 90% of the pores larger than 100 nm in any dimension are smaller than about 5 μm, or smaller than about 3 μm, or smaller than about 2 μm in any dimension. In some embodiments, the continuous porous lithium storage layer may contain some pores that are smaller than 100 nm in any dimension, or smaller than 50 nm in any dimension, or smaller than 20 nm in any dimension. In some embodiments, the continuous porous lithium storage layer has a density of 1.0 to 1.1 g / cm. 3 , or 1.1 to 1.2 g / cm 3 , or 1.2 to 1.3 g / cm 3 , or 1.3 to 1.4 g / cm 3 , or 1.4 to 1.5 g / cm 3 , or 1.5 to 1.6 g / cm 3 , or 1.6 to 1.7 g / cm 3 , or 1.7 to 1.8 g / cm 3 , or 1.8 to 1.9 g / cm 3 , or 1.9 to 2.0 g / cm 3 , or 2.0 to 2.1 g / cm 3 , or 2.1 to 2.2 g / cm 3 , or 2.2 to 2.25 g / cm 3or any combination of continuous ranges thereof, and containing at least 40 atomic % silicon, alternatively at least 50 atomic % silicon, alternatively at least 60 atomic % silicon, alternatively at least 70 atomic % silicon, alternatively at least 80 atomic % silicon, alternatively at least 90 atomic % silicon, alternatively at least 95 atomic % silicon.

[0039] In some embodiments, the majority of the active material (e.g., silicon, germanium, or alloys thereof) of the continuous porous lithium storage layer has substantial lateral connectivity across a portion of the current collector, with such connectivity extending around the random pores and interstices (as described below). Referring again to FIG. 1 , in some embodiments, “substantial lateral connectivity” means that the active material at one point X of the continuous porous lithium storage layer 107 can be connected to the active material at a second point X′ of the layer over a linear lateral distance L that is at least as large as the thickness T of the continuous porous lithium storage layer, or a lateral distance at least twice the thickness, or a lateral distance at least three times the thickness. Although not shown, the total distance of the material connections, including the surrounding pores, may be longer than L. In some embodiments, the continuous porous lithium storage layer can be described as a matrix of interconnected silicon, germanium, or alloys thereof, embedded with random pores and interstices. In some embodiments, the continuous porous lithium storage layer has a sponge-like morphology. In some embodiments, at least prior to electrochemical formation, about 75% or more of the metal oxide layer surface is continuous with the continuous porous lithium storage layer. Note that the continuous porous lithium storage layer does not necessarily extend across the entire anode without any lateral breaks, but may include random discontinuities or cracks and still be considered continuous.

[0040] In some embodiments, the continuous porous lithium storage layer is made of silicon (SiO x ), germanium (GeO x ) or tin (SnO x), where the ratio of oxygen atoms to silicon, germanium, or tin atoms is less than 2:1, i.e., x<2, or less than 1:1, i.e., x<1. In some embodiments, x is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, alternatively 0.50 to 0.95, alternatively 0.95 to 1.25, alternatively 1.25 to 1.50, or any combination of consecutive ranges thereof.

[0041] In some embodiments, the continuous porous lithium storage layer is made of silicon (SiN y ), germanium (GeN y ) or tin (SnN y ), where the ratio of nitrogen atoms to silicon, germanium, or tin atoms is less than 1.25:1, i.e., y<1.25. In some embodiments, y is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, alternatively 0.50 to 0.95, alternatively 0.95 to 1.20, or any combination of consecutive ranges thereof.

[0042] In some embodiments, the continuous porous lithium storage layer is made of silicon (SiO ) with a ratio of total oxygen and nitrogen atoms to silicon, germanium, or tin atoms of less than 1:1, i.e., (x+y)<1. x N y ), germanium (GeO x N y ) or tin (SnO x N y In some embodiments, (x+y) is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, alternatively 0.50 to 0.95, or any combination of consecutive ranges thereof.

[0043] In some embodiments, the sub-stoichiometric oxide, nitride, or oxynitride is provided by a CVD process, including but not limited to a PECVD process. The oxygen and nitrogen may be uniformly provided within the continuous porous lithium storage layer, or the oxygen or nitrogen content may vary as a function of the thickness of the storage layer.

[0044] 6, anode 600 includes a continuous porous lithium storage layer 607 disposed on a current collector 601 including a metal oxide layer 605 and a conductive layer 603. In some embodiments, continuous porous lithium storage layer 607 includes multiple continuous porous lithium storage sublayers (607a and 607b) having different physical properties or chemical compositions and independently selected from any of the above embodiments. For example, lithium storage sublayer 607a can include amorphous silicon with a low oxygen content, and lithium storage sublayer 607b can include a silicon suboxide, SiO x where x ranges from 0.02 to 0.95. Alternatively, the compositions of 607a and 607b can be reversed. In another example, lithium storage sublayer 607a may include amorphous silicon with low germanium, and lithium storage sublayer 607b includes a higher atomic % germanium than 607a. In some embodiments, the lithium storage sublayers may have different amounts or types of dopants. In some other embodiments, lithium storage sublayers 607a and 607b have similar chemical compositions, but 607a has a higher density than 607b. These are just a few non-limiting examples. Many other combinations are possible. While two lithium storage sublayers are shown in FIG. 6, three or more sublayers may be used instead.

[0045] In some embodiments, the continuous porous lithium storage layer comprises a gradient in composition, density, or porosity, or a combination thereof, as a function of layer thickness. For example, the continuous porous lithium storage layer 107 may comprise amorphous silicon that is denser near the metal oxide layer 105 than near the top surface 108, or vice versa.

[0046] Additional lithium storage layer The generally planar nature of some embodiments of the present anode further allows for the simple coating of an additional lithium storage layer other than the continuous, porous lithium storage layer described herein. For example, a conventional carbon-based lithium ion battery slurry, which may optionally further include silicon particles, can be coated onto the continuous, porous lithium storage layer of the present disclosure to further enhance charge capacity. Coating methods can include curtain coating, slot coating, spin coating, inkjet coating, spray coating, or any other suitable method.

[0047] CVD CVD generally involves flowing a precursor gas, a gasified liquid in the case of direct liquid injection CVD, or a gas and liquid into a chamber typically containing one or more objects to be coated, which is heated. Chemical reactions occur at and near the hot surface, depositing a thin film on the surface. This is accompanied by the production of chemical by-products that are exhausted from the chamber along with unreacted precursor gas. As expected for the wide variety of deposited materials and wide range of applications, there are many variations of CVD that can be used to form lithium storage layers, metal oxide layers, auxiliary layers (see below), or other layers. This can be performed in some embodiments in hot-wall or cold-wall reactors, with or without a carrier gas, at total pressures from below torr to above atmospheric pressure, and at temperatures typically ranging from 100 to 1600 °C. There are also various modified CVD processes, including the use of plasma, ion, photon, laser, hot filament, or combustion reactions to increase deposition rate and / or reduce deposition temperature. Deposition can be controlled using various process conditions, including, but not limited to, temperature, precursor material, amount of gas flow, pressure, substrate voltage bias (if applicable), and plasma energy (if applicable).

[0048] As described above, a continuous porous lithium storage layer, such as a layer of silicon or germanium or both, can be provided by plasma enhanced chemical vapor deposition (PECVD). Compared to conventional CVD, deposition by PECVD is often performed at lower temperatures and higher rates, which can be advantageous for higher manufacturing throughput. In some embodiments, PECVD is used to deposit a substantially amorphous silicon layer (optionally doped) on a metal oxide layer. In some embodiments, PECVD is used to deposit a substantially amorphous continuous porous silicon layer on a metal oxide layer.

[0049] PECVD In a PECVD process, according to various embodiments, a plasma can be generated in or upstream of the chamber in which the substrate is located and delivered to the chamber. Various types of plasma can be used, including, but not limited to, capacitively coupled plasma, inductively coupled plasma, and conductively coupled plasma. Any suitable plasma source can be used, including DC, AC, RF, VHF, combinatorial PECVD, and microwave sources. Some non-limiting examples of useful PECVD tools include hollow cathode tube PECVD, magnetron confined PECVD, inductively coupled plasma chemical vapor deposition (ICP-PECVD, sometimes referred to as HDPECVD, ICP-CVD, or HDCVD), and expanding thermal plasma chemical vapor deposition (ETP-PECVD).

[0050] PECVD process conditions (temperature, pressure, precursor gases, carrier gases, dopant gases, flow rates, energy, etc.) can vary according to the particular process and tools used, as is well known in the art.

[0051] In some embodiments, the PECVD process is an expanding thermal plasma chemical vapor deposition (ETP-PECVD) process. In such a process, a plasma-generating gas is passed through a direct current arc plasma generator, optionally with a web or other substrate, including a current collector, in an adjacent vacuum chamber to form a plasma. A silicon source gas is injected into the plasma, generating radicals. The plasma is expanded through a branching nozzle and injected into the vacuum chamber toward the substrate. An example of a plasma-generating gas is argon (Ar). In some embodiments, ionized argon species in the plasma collide with silicon source molecules to form silicon source radical species, which are deposited on the current collector. Exemplary ranges for the voltage and current of the DC plasma source are 60-80 volts and 40-70 amperes, respectively.

[0052] Silicon can be deposited using any suitable silicon source, including silane (SiH), dichlorosilane (HSiCl), monochlorosilane (HSiCl), trichlorosilane (HSiCl), silicon tetrachloride (SiCl), and diethylsilane. Depending on the gas used, the silicon layer can be formed by decomposition or reaction with another compound, such as by hydrogen reduction. In some embodiments, the gas can include a silicon source such as silane, a noble gas such as helium, argon, neon, or xenon, optionally one or more dopant gases, and can be substantially free of hydrogen. In some embodiments, the gas can include argon, silane, and hydrogen, and optionally some dopant gases. In some embodiments, the ratio of the argon gas flow to the combined silane and hydrogen gas flow is at least 3.0, or alternatively at least 4.0. In some embodiments, the ratio of the argon gas flow to the combined silane and hydrogen gas flow is between 3 and 5, alternatively between 5 and 10, alternatively between 10 and 15, alternatively between 15 and 20, or any combination of consecutive ranges thereof. In some embodiments, the ratio of the hydrogen gas flow to the silane gas flow is between 0 and 0.1, alternatively between 0.1 and 0.2, alternatively between 0.2 and 0.5, alternatively between 0.5 and 1, alternatively between 1 and 2, alternatively between 2 and 5, or any combination of consecutive ranges thereof. In some embodiments, increasing the ratio of the silane gas flow to the combined silane and hydrogen gas flow may result in the formation of more porous silicon and / or an increased silicon deposition rate. In some embodiments, the dopant gas is borane or phosphine, optionally mixed with a carrier gas.In some embodiments, the ratio of the gas flow rates of the dopant gas (e.g., borane or phosphine) to the silicon source gas (e.g., silane) is within the range of 0.0001 to 0.0002, alternatively 0.0002 to 0.0005, alternatively 0.0005 to 0.001, alternatively 0.001 to 0.002, alternatively 0.002 to 0.005, alternatively 0.005 to 0.01, alternatively 0.01 to 0.02, alternatively 0.02 to 0.05, alternatively 0.05 to 0.10, or any combination of consecutive ranges thereof. Such gas flow rate ratios described above can refer to relative gas flow rates, for example, in standard cubic centimeters per minute (SCCM). In some embodiments, the PECVD deposition conditions and gases can be varied over the course of deposition.

[0053] In some embodiments, the temperature of the current collector during at least a portion of the PECVD deposition period is in the range of 100°C to 200°C, alternatively 200°C to 300°C, alternatively 300°C to 400°C, alternatively 400°C to 500°C, alternatively 500°C to 600°C, or any combination of consecutive ranges thereof. In some embodiments, the temperature can vary during the PECVD deposition period. For example, the temperature during the early periods of PECVD can be higher than the later periods. Alternatively, the temperature during the later periods of PECVD can be higher than the earlier periods.

[0054] The thickness or mass per unit area of ​​the continuous porous lithium storage layer depends on the storage material, the desired charge capacity, and other operational and life considerations. Increasing the thickness generally results in more capacity. If the continuous porous lithium storage layer becomes too thick, electrical resistance may increase and stability may decrease. In some embodiments, the anode has a mass of at least 0.5 mg / cm. 2 , or at least 1.0 mg / cm 2 , or at least 1.5 mg / cm 2 , or at least 3 mg / cm 2 , or at least 5 mg / cm 2In some embodiments, the lithium storage structure can be characterized as having an active silicon areal density of 0.5 to 1.5 mg / cm. 2 or 1.5-2 mg / cm 2 in the range of 2-3 mg / cm 2 in the range of 3-5 mg / cm 2 in the range of 5-10 mg / cm 2 range, or 10-15 mg / cm 2 range, or 15-20 mg / cm 2 or any combination of continuous ranges thereof. "Active silicon areal density" refers to the silicon in electrical communication with the current collector available for reversible lithium storage at the beginning of a cell cycle, e.g., after the anode "electrochemical formation" described below. The term "area" refers to the surface area of ​​the conductive layer on which the active silicon is provided. In some embodiments, not all of the silicon content is active silicon, i.e., some may be bound in the form of inactive silicide or electrically isolated from the current collector.

[0055] In some embodiments, the continuous porous lithium reservoir has an average thickness of at least 0.5 μm, alternatively at least 1 μm, alternatively at least 3 μm, alternatively at least 7 μm. In some embodiments, the continuous porous lithium reservoir has an average thickness ranging from about 0.5 μm to about 50 μm. In some embodiments, the continuous porous lithium reservoir comprises at least 85 atomic % amorphous silicon and has a thickness ranging from 0.5 to 1 μm, alternatively 1 to 2 μm, alternatively 2 to 4 μm, alternatively 4 to 7 μm, alternatively 7 to 10 μm, alternatively 10 to 15 μm, alternatively 15 to 20 μm, alternatively 20 to 25 μm, alternatively 25 to 30 μm, alternatively 30 to 40 μm, alternatively 40 to 50 μm, or any combination of consecutive ranges thereof.

[0056] In some embodiments, the continuous porous lithium storage layer contains silicon but does not contain substantial amounts of crystalline silicide, i.e., the presence of silicide is not readily detected by X-ray diffraction (XRD). Metal silicides, such as nickel silicide, are typically formed when silicon is deposited directly onto a metal, such as nickel foil, at higher temperatures. Metal silicides, such as nickel silicide, often have much lower lithium storage capacities than silicon itself. In some embodiments, the average atomic % of silicide-forming metal elements in the continuous porous lithium storage layer is less than 35%, alternatively less than 20%, alternatively less than 10%, or alternatively less than 5%. In some embodiments, the average atomic % of silicide-forming metal elements in the continuous porous lithium storage layer ranges from about 0.01% to about 10%, alternatively from about 0.05 to about 5%. In some embodiments, the atomic % of silicide-forming metal elements in the continuous porous lithium storage layer is higher closer to the current collector than further away from the current collector.

[0057] Other Anode Features In some embodiments, the anode may further include one or more auxiliary layers. As shown in FIG. 7A, auxiliary layer 750 is provided on the surface of continuous porous lithium storage layer 707, which covers current collector 701 including metal oxide layer 705 and conductive layer 703. In some embodiments, the auxiliary layer is a protective layer to enhance lifetime or physical durability. The auxiliary layer may be an oxide or nitride formed from the lithium storage material itself, such as silicon dioxide, silicon nitride, or silicon oxynitride in the case of silicon. The auxiliary layer may be deposited by, for example, ALD, CVD, PECVD, evaporation, sputtering, solution coating, inkjet, or any method compatible with the anode. In some embodiments, the auxiliary layer is deposited in the same CVD or PECVD apparatus as the continuous lithium storage layer. For example, a stoichiometric silicon dioxide or silicon nitride auxiliary layer is formed by introducing an oxygen- or nitrogen-containing gas (or both) with the silicon precursor gas used to form the continuous porous lithium storage layer. In some embodiments, the auxiliary layer may include boron nitride or silicon carbide. In some embodiments, the auxiliary layer 750 can include a metal compound, as described below.

[0058] As shown in FIG. 7B , in some embodiments, the anode includes a first auxiliary layer 750-1 and a second auxiliary layer 750-2 that cover the first auxiliary layer and have a different chemical composition than the first auxiliary layer. In some embodiments, the first auxiliary layer 750-1 can include silicon nitride, silicon dioxide, silicon oxynitride, or a first metal compound. The second auxiliary layer 750-2 has a different composition than the first auxiliary layer and can include silicon nitride, silicon dioxide, silicon oxynitride, or a second metal compound. In some embodiments, the second auxiliary layer can be in contact with the first auxiliary layer. In some embodiments, one or more additional auxiliary layers can be provided on the second auxiliary layer. In some embodiments with two or more auxiliary layers, each auxiliary layer is in contact with at least one other auxiliary layer.

[0059] In some embodiments, the first auxiliary layer 750-1 and any second or additional auxiliary layers may help stabilize the continuous porous lithium storage layer by providing a barrier against direct electrochemical reaction with the solvent or electrolyte, which could degrade the interface. The auxiliary layers should be reasonably conductive to lithium ions, allowing them to move in and out of the continuous porous lithium storage layer during charge and discharge. In some embodiments, the lithium ion conductivity of the auxiliary layers is at least 10 -9 S / cm, or at least 10 -8 S / cm, or at least 10 -7 S / cm, or at least 10 -6 S / cm. In some embodiments, the auxiliary layer acts as a solid electrolyte. In some embodiments, the auxiliary layer is less conductive than the lithium storage structure, so little or no electrochemical reduction of lithium ions to lithium metal occurs at the auxiliary layer / electrolyte interface. In addition to providing protection from electrochemical reactions, multiple auxiliary layer structures can provide excellent structural support. In some embodiments, expansion of the continuous porous lithium storage layer during lithiation can cause the auxiliary layer to flex and form cracks. However, crack propagation can be dispersed between layers to reduce direct exposure of the lithium storage structure to the bulk electrolyte. For example, cracks in the second auxiliary layer may not be aligned with those in the first auxiliary layer. Such an advantage would not occur if only one thick auxiliary layer were used. In one embodiment, the second auxiliary layer may be formed of a material that is more flexible than the first auxiliary layer.

[0060] In some embodiments, the auxiliary layer (first auxiliary layer, second auxiliary layer, or any additional auxiliary layer) can comprise silicon nitride, e.g., substantially stoichiometric silicon nitride having a nitrogen-to-silicon ratio in the range of 1.33 to 1.25. The auxiliary layer comprising silicon nitride can have an average thickness in the range of about 0.5 nm to 1 nm, alternatively 1 nm to 2 nm, alternatively 2 nm to 10 nm, alternatively 10 nm to 20 nm, alternatively 20 nm to 30 nm, alternatively 30 nm to 40 nm, alternatively 40 nm to 50 nm, or any combination of consecutive ranges thereof. Silicon nitride can be deposited by an atomic layer deposition (ALD) process or a CVD process. In some embodiments, the continuous porous lithium storage layer comprises silicon deposited by some type of CVD process, as described above, and finally, a nitrogen gas source is added to the CVD deposition chamber along with the silicon source.

[0061] In some embodiments, the auxiliary layer (first auxiliary layer, second auxiliary layer, or any additional auxiliary layer) can comprise silicon dioxide, e.g., substantially stoichiometric silicon dioxide having an oxygen to silicon ratio in the range of 2.0 to 1.9. The auxiliary layer comprising silicon dioxide can have an average thickness in the range of about 2 nm to 10 nm, alternatively 10 nm to 30 nm, alternatively 30 nm to 50 nm, alternatively 50 nm to 70 nm, alternatively 70 nm to 100 nm, alternatively 100 nm to 150 nm, alternatively 150 nm to 200 nm, or any combination of consecutive ranges thereof. The silicon dioxide can be deposited by an atomic layer deposition (ALD) process or a CVD process. In some embodiments, the continuous porous lithium storage layer comprises silicon deposited by any type of CVD process, as described above, and finally, an oxygen-containing gas source is added to the CVD deposition chamber along with the silicon source.

[0062] In some embodiments, the auxiliary layer (first auxiliary layer, second auxiliary layer, or any additional auxiliary layer) is a silicon oxynitride, such as a substantially stoichiometric silicon oxynitride (SiO x N y), where the sum of 0.5x and 0.75y is within the range of 1.00 to 0.95. The auxiliary layer including silicon nitride can have an average thickness in the range of about 0.5 nm to 1 nm, alternatively 1 nm to 2 nm, alternatively 2 nm to 10 nm, alternatively 10 nm to 20 nm, alternatively 20 nm to 30 nm, alternatively 30 nm to 40 nm, alternatively 40 nm to 50 nm, alternatively 50 nm to 70 nm, alternatively 70 nm to 100 nm, alternatively 100 nm to 150 nm, or any combination of consecutive ranges thereof. In some embodiments, the silicon oxynitride can be provided by a CVD process, including, but not limited to, a PECVD process. The oxygen and nitrogen can be uniformly provided within the continuous porous lithium storage layer, or the oxygen or nitrogen content can vary as a function of position (e.g., height) within the storage layer.

[0063] In some embodiments, the silicon nitride, silicon dioxide, or silicon oxynitride may be deposited by an atomic layer deposition (ALD) process or a CVD process. In some embodiments, the continuous porous lithium storage layer comprises silicon deposited by some type of CVD process as described above, and finally, a nitrogen and / or oxygen-containing gas source is added to the CVD deposition chamber along with the silicon source.

[0064] In some embodiments, the auxiliary layer (first auxiliary layer, second auxiliary layer, or any additional auxiliary layer) can comprise a metal oxide, metal nitride, or metal oxynitride, such as one containing aluminum, titanium, vanadium, zirconium, or tin, or a mixture thereof. In some embodiments, the auxiliary layer containing a metal oxide, metal nitride, or metal oxynitride can have an average thickness of less than about 100 nm, such as from about 0.5 nm to about 1 nm, or from about 1 nm to about 2 nm, or from 2 nm to 10 nm, or from 10 nm to 20 nm, or from 20 nm to 30 nm, or from 30 nm to 40 nm, or from 40 nm to 50 nm, or any combination of these continuous ranges. The metal oxide, metal nitride, or metal oxynitride can also contain other components or dopants, such as transition metals, phosphorus, or silicon.

[0065] In some embodiments, the metal compound can include a lithium-containing material such as lithium phosphorus nitrite (LIPON), lithium phosphate, lithium aluminum oxide, or lithium lanthanum titanate. In some embodiments, the thickness of the auxiliary layer including the lithium-containing material can be in the range of 0.5 nm to 200 nm, alternatively 1 nm to 10 nm, alternatively 10 nm to 20 nm, alternatively 20 nm to 30 nm, alternatively 30 nm to 40 nm, alternatively 40 nm to 50 nm, alternatively 50 nm to 100 nm, alternatively 100 nm to 200 nm, or any combination of consecutive ranges thereof.

[0066] In some embodiments, metal compounds may be deposited by processes including ALD, thermal evaporation, sputtering, or electron beam evaporation. ALD is a thin film deposition technique typically based on the sequential use of gas-phase chemical processes. Most ALD reactions typically use at least two chemicals, called precursors. These precursors react sequentially with the surface of the material in a self-limiting manner. Thin films are often conformally deposited by repeated exposure to different precursors. In addition to conventional ALD systems, so-called spatial ALD (SALD) methods and materials can be used, as described, for example, in U.S. Pat. No. 7,413,982, the entire contents of which are incorporated herein by reference for all purposes. In certain embodiments, SALD can be performed under ambient conditions and pressure and can have higher throughput than conventional ALD systems.

[0067] In some embodiments, the process for depositing the metal compound may include electroless deposition, contact with a solution, contact with a reactive gas, or electrochemical methods. In some embodiments, the metal compound can be formed by depositing a metal layer (including, but not limited to, thermal evaporation, CVD, sputtering, electron beam evaporation, electrochemical vapor deposition, or electroless deposition), followed by a treatment that converts the metal into the metal compound (including, but not limited to, contact with a reactive solution, contact with an oxidizing agent, contact with a reactive gas, or heat treatment).

[0068] The auxiliary layer can include an inorganic-organic hybrid structure with alternating layers of metal oxide and bridged organic material. These inorganic-organic hybrid structures are sometimes called "metal cones." Such structures can be fabricated using a combination of atomic layer deposition (ALD) to apply the metal compound and molecular layer deposition (MLD) to apply the organic compound. The organic bridge is typically a molecule with multiple functional groups. One group can react with the metal compound-containing layer, while the other group is available to react in a subsequent ALD step to attach new metal. A wide range of reactive organic functional groups can be used, including, but not limited to, hydroxy, carboxylic acid, amine, acid chloride, and anhydride. Nearly any metal compound suitable for ALD deposition can be used. Some non-limiting examples include ALD compounds for aluminum (e.g., trimethylaluminum), titanium (e.g., titanium tetrachloride), zinc (e.g., diethylzinc), and zirconium (tris(dimethylamino)cyclopentadienylzirconium). For the purposes of this disclosure, this alternating metal oxide / bridged organic sublayer structure is considered a single auxiliary layer of a metal cone. When the metal compound comprises aluminum, such a structure may be referred to as an alcone. Similarly, when the metal compound comprises zirconium, such a structure may be referred to as a zircon. Further examples of inorganic-organic hybrid structures that may be suitable as auxiliary layers can be found in U.S. Patent No. 9,376,455, as well as U.S. Patent Application Publication Nos. 2019 / 0044151 and 2015 / 0072119, the entire contents of which are incorporated herein by reference.

[0069] In some embodiments, the auxiliary layer having the metal cone can have a thickness in the range of 0.5 nm to 200 nm, alternatively 1 nm to 10 nm, alternatively 10 nm to 20 nm, alternatively 20 nm to 30 nm, alternatively 30 nm to 40 nm, alternatively 40 nm to 50 nm, alternatively 50 nm to 100 nm, alternatively 100 nm to 200 nm, or any combination of consecutive ranges thereof.

[0070] In some embodiments, the auxiliary layer (first, second, or additional auxiliary layer) can comprise boron nitride or silicon carbide and can have an average thickness of less than about 100 nm, for example, from about 0.5 nm to about 1 nm, alternatively from about 1 nm to about 2 nm, alternatively from 2 nm to 10 nm, alternatively from 10 nm to 20 nm, alternatively from 20 nm to 30 nm, alternatively from 30 nm to 40 nm, alternatively from 40 nm to 50 nm, or any combination of consecutive ranges thereof.

[0071] In some embodiments, the anode is at least partially prelithiated, i.e., the continuous porous lithium storage layer and / or metal oxide layer contains some lithium prior to battery assembly, i.e., before combining the anode with the cathode in a battery cell.

[0072] In some embodiments, lithium metal (or other lithiated material) is deposited on the metal oxide layer prior to depositing the continuous porous lithium storage layer. The lithium may be deposited, for example, by evaporation, e-beam, or sputtering. Some of the lithium may form lithium oxide. In embodiments where the metal oxide layer includes an oxide of a transition metal, such as copper or nickel, a mixed metal oxide may be formed. In some embodiments, depositing a lithium layer on the metal oxide can reduce first-cycle lithium loss during the electrochemical formation of the anode (described below).

[0073] In some embodiments, the lithium metal atomic to oxygen atomic loading ratio in the metal oxide layer is at least 0.02, alternatively in the range of 0.05 to 1.0. In some cases, the amount of lithium metal deposited corresponds to at least 1%, alternatively in the range of 2% to 10%, alternatively in the range of 10% to 30%, alternatively in the range of 30% to 50%, or any combination of these ranges, of the maximum lithium areal capacity of the continuous porous lithium storage layer.

[0074] In some embodiments, the continuous porous lithium storage layer may be at least partially prelithiated before the first electrochemical cycle after battery assembly, or alternatively, before battery assembly. That is, even before the first battery cycle, some lithium may be incorporated into the continuous porous lithium storage layer to form a lithiated storage layer. In some embodiments, the lithiated storage layer may be broken down into smaller structures, including, but not limited to, platelets, that remain electrochemically active and continue to reversibly store lithium. Note that the term "lithiated storage layer" simply means that at least a portion of the potential storage capacity of the lithium storage layer is filled, but not necessarily all of it. In some embodiments, the lithiated storage layer can contain lithium in the range of 1% to 10%, alternatively 10% to 20%, alternatively 20% to 30%, alternatively 30% to 40%, alternatively 40% to 50%, alternatively 50% to 60%, alternatively 60% to 70%, alternatively 70% to 80%, alternatively 80% to 90%, alternatively 90% to 100% of the theoretical lithium storage capacity of the continuous porous lithium storage layer, or any combination of contiguous ranges thereof. In some embodiments, the metal oxide layer may trap some of the lithium, and such trapping may need to be taken into account to achieve the desired lithium range in the lithiated storage layer.

[0075] In some embodiments, prelithiation can include depositing lithium metal onto the continuous porous lithium storage layer, or between one or more lithium storage sublayers, or both, for example by evaporation, electron beam, or sputtering. Alternatively, prelithiation can include contacting the anode with a reducible lithium organic compound, such as lithium naphthalene, n-butyllithium, or the like. In some embodiments, prelithiation can include incorporating lithium by electrochemical reduction of lithium ions in a prelithiation solution.

[0076] In some embodiments, one or more auxiliary layers (described above) may be formed on the continuous porous lithium storage layer prior to prelithiation. The auxiliary layer can be used to control the lithium uptake rate. Non-limiting examples of auxiliary layer materials include silicon nitride, metal oxides, metal nitrides, or metal oxynitrides.

[0077] In some embodiments, prelithiation involves physical contact of the continuous porous lithium storage layer with the lithiated material. The lithiated material may include a reducible lithium compound, lithium metal, or a stabilized lithium metal powder, any of which may be provided as a coating on a lithium transfer substrate. The lithium transfer substrate may include a metal (e.g., as a foil), a polymer, a ceramic, or some combination of such materials, optionally in a multilayer format. In some embodiments, such a lithiated material may be provided on at least one side of a current separator facing the anode, i.e., the current separator also serves as the lithium transfer substrate. Stabilized lithium metal powders ("SLMPs") typically have a phosphate, carbonate, or other coating on the lithium metal particles, as described, for example, in U.S. Pat. Nos. 8,377,236, 6,911,280, 5,567,474, 5,776,369, and 5,976,403, the entire contents of which are incorporated herein by reference. In some embodiments, SLMP may require physical pressure to break down the coating and allow lithium incorporation into the continuous, porous lithium storage layer. In some embodiments, pressure and / or heat may be applied to the other lithiated material to facilitate lithium migration into the continuous lithium storage layer, optionally through one or more auxiliary layers. In some embodiments, the pressure applied between the anode and the lithiated material may be at least 200 kPa, alternatively at least 1000 kPa, or alternatively at least 5000 kPa. Pressure may be applied, for example, by calendaring, pressure plates, or, in the case of a lithiated material coating on a current separator, by assembly into a battery with a confinement or other pressure mechanism.

[0078] In some embodiments, prelithiation involves heat-treating the continuous, porous lithium storage layer during lithium incorporation, after lithium incorporation, or both during and after. Heat-treating can aid in the incorporation of lithium into the continuous, porous lithium storage layer, for example, by promoting lithium diffusion. In some embodiments, heat-treating involves exposing the anode to a temperature ranging from 50°C to 100°C, alternatively from 100°C to 150°C, alternatively from 150°C to 200°C, alternatively from 200°C to 250°C, alternatively from 250°C to 300°C, or alternatively from 300°C to 350°C. In some embodiments, heat-treating can be performed under a controlled atmosphere, such as a vacuum or argon atmosphere, to avoid undesired reactions with oxygen, nitrogen, water, or other reactive gases.

[0079] In some embodiments, prelithiation can soften the continuous porous lithium storage layer, for example, due to the formation of a lithium-silicon alloy. This softening can cause problems in some processes, such as roll-to-roll processes, where the softened lithium storage layer begins to adhere to the roller or to itself during winding. In some embodiments, providing one or more auxiliary layers before or after prelithiation can substantially improve the structural integrity and processability of the anode. In some embodiments, the auxiliary layer can act as a harder interface with other surfaces, preventing or reducing contact between such surfaces and the softened lithium storage material.

[0080] In some embodiments, lithium metal can be deposited on the continuous, porous lithium storage layer, followed by the deposition of the lithium ion conducting layer. The anode may be heat-treated before the deposition of the lithium ion conducting layer, after the deposition of the lithium ion conducting layer, or both. In some embodiments, lithium metal is deposited directly on the continuous, porous lithium storage layer. In some embodiments, a sublayer, such as silicon nitride, is deposited on the continuous, porous lithium storage layer before the deposition of the lithium metal. In some embodiments, the lithium ion conducting layer can include a lithium-containing material, a metal oxide, or a metal cone. Some non-limiting examples of lithium ion conducting layer materials include lithium phosphate nitride (LIPON), lithium phosphate, lithium aluminum oxide, lithium lanthanum titanate, and alcone. The lithium ion conducting layer may include multiple sublayers of different materials, for example, selected from the list above.

[0081] In some embodiments, the anode may be treated with a reducing agent prior to final battery assembly. The reducing agent may have an electrochemical potential sufficient to reduce at least a portion of the metal oxide layer. The reducing agent may include inorganic hydrides, substituted or unsubstituted borohydrides, amine-boranes, or anionic organic aromatic compounds. In some embodiments, the reducing agent may be provided in a non-aqueous solvent that is not itself reduced by the reducing agent and is applied under controlled conditions with low oxygen and moisture.

[0082] While heat treatment is described above with respect to prelithiation and metal oxide precursors, in some embodiments, the anode may be heat-treated with or without a prelithiation step prior to battery assembly (after deposition of the continuous, porous lithium storage layer is complete, but before the anode is combined with the cathode in a battery cell). In some embodiments, heat-treating the anode can improve the adhesion or conductivity of various layers, for example, by inducing migration of atoms from the current collector (i.e., the metal oxide layer or the underlying conductive metal layer) or from any auxiliary layers into the continuous, porous lithium storage layer. In some embodiments, heat-treating the anode can be performed in a controlled environment, such as vacuum, argon, or nitrogen with low oxygen and water content (e.g., less than 100 ppm, or partial pressures less than 10 Torr, or less than 1 Torr, or less than 0.1 Torr, to prevent degradation). As used herein, "under vacuum" generally refers to reduced pressure conditions where the total pressure of all gases (e.g., in a vacuum oven) is less than 10 Torr. Due to equipment limitations, vacuum pressures are typically around 10 -8 Torr or greater. In some embodiments, the anodic heat treatment can be performed using an oven, a tube furnace, an infrared heating element, contact with a hot surface (e.g., a hot plate), or exposure to a flash lamp. The temperature and time of the anodic heat treatment depend on the anode material. In some embodiments, the anodic heat treatment comprises heating the anode to a temperature of at least 50°C, optionally between 50°C and 600°C, alternatively between 100°C and 250°C, alternatively between 250°C and 350°C, alternatively between 350°C and 450°C, alternatively between 450°C and 600°C, alternatively between 600°C and 700°C, alternatively between 700°C and 800°C, or any combination of successive ranges thereof. In some embodiments, the anode heat treatment time may be in the range of about 0.1 minutes to about 1 minute, alternatively about 1 minute to about 5 minutes, alternatively about 5 minutes to about 10 minutes, alternatively about 10 minutes to about 30 minutes, alternatively about 30 minutes to about 60 minutes, alternatively about 60 minutes to about 90 minutes, alternatively about 90 minutes to about 120 minutes, or any combination of consecutive ranges thereof.

[0083] As shown in FIG. 8, there are numerous process flow options for fabricating batteries incorporating the anodes of the present disclosure. All steps in FIG. 8 are described in more detail above, and FIG. 8 is not an exhaustive list of all possibilities. In some embodiments, at least steps 801, 805, and 817 are followed. In step 801, a metal oxide layer is formed on a conductive layer, e.g., a conductive metal layer such as a metal foil or metal mesh. In step 805, one or more continuous porous lithium storage layers are deposited on the metal oxide layer. In an alternative embodiment, prior to step 805, lithium metal (or other lithiated material) can be deposited on the metal oxide layer, as shown in step 803. In some cases, the anode formed in step 805 is ready for assembly into a battery in step 817.

[0084] In some embodiments, step 805 may be followed by a prelithiation step, e.g., step 807, in which lithium metal may be deposited on the continuous, porous lithium storage layer. In some cases, the anode from step 807 may be ready for assembly into a battery in step 817. In other embodiments, shown in step 811, one or more lithium ion conducting layers may be deposited on the product of step 807 prior to the battery assembly step 817.

[0085] In some embodiments, after step 805, one or more auxiliary layers may be deposited on the continuous porous lithium storage layer, as shown in step 809. In some cases, the anode from step 809 is ready for assembly into a battery in step 817. In other embodiments, a pre-lithiation step may be included, and lithium metal may be deposited on the auxiliary layer, as shown in step 813, for example. In some cases, the anode from step 813 is ready for assembly into a battery in step 817. In other embodiments, one or more lithium ion conducting layers may be deposited on the product of step 813 prior to battery assembly step 817.

[0086] 8, heat treatments or other treatments can be performed between any of the steps. Furthermore, as noted above, an additional lithium storage layer that is not a continuous, porous lithium storage layer can be coated after step 805. In some embodiments, one or more steps can be performed using a roll-to-roll coating method, where the conductive layer is in the form of a rolled film, e.g., a roll of metal foil.

[0087] In some cases, as shown in schematic Figure 9A, roll-to-roll processing may be performed within a particular step, and the apparatus 901 for such a step includes the processing hardware 903 necessary to deposit, form, or process the layers, along with, for example, a loading tool 905 for holding a roll of film 906 to be processed, and a winding tool 907 for rolling up the processed film 908 after the step is complete. To perform the next step, the processed roll may be transported to a processing apparatus 911 with its own processing hardware 913, loading tool 915, and winding tool 917. During transport, the roll may be kept in a controlled environment, e.g., low oxygen or low moisture, depending on the step.

[0088] In some cases, roll-to-roll processing can involve transferring a film processed in one step directly to the next step or apparatus, as shown schematically in FIG. 9B. Processing apparatus 921 is similar to apparatus 901 but does not include a reeling tool. Apparatus 921 includes a loading tool 925 for holding a roll of film 926 to be processed and appropriate processing hardware 923, e.g., for depositing, forming, or processing a layer. The processed film 928 from the first step moves to processing apparatus 931 to receive another processing step. Apparatus 931 includes appropriate processing hardware 933, e.g., for depositing, forming, or processing a layer, and a reeling tool 937 for rolling up the processed film 938 after the next step is completed. Although not shown, the processed film 938 may instead move to yet another processing apparatus without reeling. Also, while depicted as separate units, in some embodiments, apparatus 921 and apparatus 931 may share a common chamber. In some embodiments, a transition chamber or zone may be provided between apparatus 921 and 931 designed to prevent one process from contaminating another or to act as a film transport speed buffer when one process requires less time than another.

[0089] Various combinations of the above embodiments can be used together, depending on the compatibility of one device to interface with another. The shaping apparatus may further include a slitting station.

[0090] Battery Features The preceding discussion has primarily focused on the anode (negative electrode) of a lithium-ion battery (LIB). LIBs typically include a cathode (positive electrode), an electrolyte, and a separator (if a solid electrolyte is not used). As is well known, batteries can be formed into multilayer stacks of anodes and cathodes with intervening separators. Alternatively, a single anode / cathode stack can be formed into a so-called jelly roll. Such a structure is provided within a suitable housing with the desired electrical contacts.

[0091] In some embodiments, the battery may be configured with a confinement mechanism to limit battery expansion, as described, for example, in U.S. Patent Application Publication Nos. 2018 / 0145367 and 2018 / 0166735, the entire contents of which are incorporated herein by reference for all purposes. In some embodiments, physical pressure is applied between the anode and cathode using, for example, a tensioned spring or clip, a compressible film, or the like. The confinement, pressure, or both can help ensure that the anode remains in active contact with the current collector during formation and cycling, which can cause expansion and contraction of the continuous porous lithium storage layer. In some embodiments, a jellyroll battery design using a metal or other rigid cylindrical housing can provide effective confinement, pressure, or both.

[0092] FIG. 10 is a schematic cross-sectional view of a battery according to some embodiments of the present disclosure. The battery 790 includes a top plate 760, a bottom plate 762, an anode side plate 764, and a cathode side plate 766, which form part of a housing for a stack of anodes 700, cathodes 740, and an intervening separator 730. The anodes are attached to an anode bus 720 connected to an anode lead 722 extending through the anode side plate 764. The cathodes are attached to a cathode bus 750 connected to a cathode lead 752 extending through the cathode side plate 766. The battery 790 further includes an electrolyte 780 that fills the space and saturates the separator 730. An upper compression member 770 and a lower compression member 772 apply physical pressure (arrows) between the anode and cathode. The compression members may be compressible films made, for example, from a porous polymer or silicone. Alternatively, the compression members may include an array of compressible features made, for example, from a porous polymer or silicone. Alternatively, the compression members may include a spring or an array of springs. Alternatively, the compression members may correspond to two sides of a compression clip or clamp. In some embodiments, the separator may act as a compressible film. In some embodiments, the top and bottom plates may be made of a material and / or structured to resist deformation, thereby containing battery expansion.

[0093] Cathode Cathode (negative electrode) materials include lithium metal oxides or compounds (e.g., LiCoO2, LiFePO4, LiMnO2, LiNiO2, LiMn2O4, LiCoPO4, LiNi x Co y Mn z O2, LiNi X Co Y Al ZExamples of cathode active materials include, but are not limited to, O, LiFe(SO) or LiFeSiO, fluorocarbons, metal fluorides such as iron fluoride (FeF), metal oxides, sulfur, selenium, sulfur-selenium, and combinations thereof. The cathode active material is typically disposed on or in electrical communication with an electrically conductive cathode current collector.

[0094] In some embodiments, the prelithiated anodes of the present disclosure are used with cathodes containing sulfur, selenium, or both sulfur and selenium (collectively referred to herein as "chalcogen cathodes"). In some embodiments, the prelithiated anodes of the present disclosure can be paired with chalcogen cathodes having an active material layer, the active material layer comprising a carbon material and Se, Se, y S x , Te y S x , Te z Se y S x and a selected compound selected from the group consisting of x, y, and z, where x, y, and z are any value between 0 and 1, the sum of y and x is 1, and the sum of z, y, and x is 1, and the compound is impregnated into the carbon material, for example, as described in U.S. Patent Application Publication No. 2019 / 0097275, incorporated herein by reference for all purposes. The compound may be present in an amount of 9 to 90% by weight based on the total weight of the active material layer. In some embodiments, the chalcogenide cathode active material layer may further include conductive carbon nanotubes to improve overall conductivity and physical durability, allowing for faster charge and discharge. The presence of carbon nanotubes may also allow for thicker coatings with greater flexibility, thereby enabling higher capacity.

[0095] Chalcogenide cathodes are commonly paired with lithium metal anodes. However, lithium metal anodes are difficult to handle, prone to degradation, and may allow the formation of dangerous lithium dendrites that can result in catastrophic short circuits. In some embodiments, the prelithiated anodes of the present disclosure can achieve energy storage capacities comparable to those of pure lithium anodes, but are much easier to handle and less prone to forming lithium dendrites, making them more compatible with chalcogenide cathodes.

[0096] Current Separator Current separators allow ions to flow between the anode and cathode while preventing direct electrical contact. Such separators are typically porous sheets. Non-aqueous lithium-ion separators, particularly for small batteries, are typically monolayer or multilayer polymer sheets made of polyolefins. Most commonly, they are based on polyethylene or polypropylene, but polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF) can also be used. For example, the separator can have a porosity greater than 30%, low ionic resistivity, a thickness of about 10 to 50 μm, and high bulk puncture strength. Alternatively, the separator may comprise a glass material, a ceramic material, a ceramic material embedded in a polymer, a ceramic-coated polymer, or some other composite or multilayer structure, for example, to provide greater mechanical and thermal stability. As mentioned above, the separator can comprise a lithiated material, such as lithium metal, a reducible lithium compound, or an SLMP material, coated on at least the side facing the anode.

[0097] electrolyte The electrolyte in a lithium-ion battery can be liquid, solid, or gel. A typical liquid electrolyte contains one or more solvents and one or more salts, at least one of which contains lithium. During the first few charging cycles (sometimes called the formation cycle), the organic solvent and / or electrolyte can partially decompose on the negative electrode surface to form a solid-electrolyte-interface (SEI) layer. The SEI is generally electrically insulating but ionically conductive, allowing lithium ions to pass through. The SEI can reduce electrolyte decomposition during subsequent charging cycles.

[0098] Some non-limiting examples of non-aqueous solvents suitable for some lithium-ion batteries include the following: cyclic carbonates (e.g., ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), butylene carbonate (BC), and vinylethylene carbonate (VEC)), vinylene carbonate (VC), lactones (e.g., γ-butyrolactone (GBL), γ-valerolactone (GVL), and α-angelicalactone (AGL)), linear carbonates (e.g., dimethyl carbonate (DMC), methyl ethyl carbonate (MEC, commonly also abbreviated as EMC), diethyl carbonate (DEC), methyl propyl carbonate (MPC), dipropyl carbonate (DP), and methyl methyl ester carbonate (MME). C), methyl butyl carbonate (NBC), and dibutyl carbonate (DBC), ethers (e.g., tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, and 1,2-dibutoxyethane), nitriles (e.g., acetonitrile and adiponitrile), linear esters (e.g., methyl propionate, methyl pivalate, butyl pivalate, and octyl pivalate), amides (e.g., dimethylformamide), organic phosphates (e.g., trimethyl phosphate and trioctyl phosphate), organic compounds containing an S═O group (e.g., dimethyl sulfone and divinyl sulfone), and combinations thereof.

[0099] Combinations of non-aqueous liquid solvents can be used. These combinations include cyclic carbonate-linear carbonate, cyclic carbonate-lactone, cyclic carbonate-lactone-linear carbonate, cyclic carbonate-linear carbonate-lactone, cyclic carbonate-linear carbonate-ether, and cyclic carbonate-linear carbonate-linear ester. In some embodiments, a cyclic carbonate can be combined with a linear ester. Alternatively, a cyclic carbonate can be combined with a lactone and a linear ester. In some embodiments, the weight or volume ratio of the cyclic carbonate to the linear ester is in the range of 1:9 to 10:1, or 2:8 to 7:3.

[0100] Salts for liquid electrolytes include, but are not limited to, the following: LiPF, LiBF, LiClO, LiAsF, LiN(CFSO), LiN(CFSO), LiCFSO, LiC(CFSO), LiPF(CF), LiPF(CF), LiPF(CF), LiPF(iso-CF), LiPF(iso-CF), lithium salts having cyclic alkyl groups (e.g., (CF)(SO) 2x Li and (CF2)3(SO2) 2x Li), and combinations thereof. Common combinations include LiPF6 and LiBF4; LiPF6 and LiN(CF3SO2)2; LiBF4 and LiN(CF3SO2)2.

[0101] In some embodiments, the total concentration of salt in the liquid non-aqueous solvent (or solvent combination) is at least 0.3 M, alternatively at least 0.7 M. The upper concentration limit may be determined by solubility limits and operating temperature range. In some embodiments, the concentration of salt is about 2.5 M or less, alternatively about 1.5 M or less.

[0102] In some embodiments, the battery electrolyte comprises a non-aqueous ionic liquid and a lithium salt.

[0103] Solid electrolytes may be used without a separator, as they function as the separator itself. They are electrically insulating, ionically conductive, and electrochemically stable. Solid electrolyte configurations use a lithium-containing salt, which may be the same as the liquid electrolyte battery described above, but is held in a solid polymer composite rather than dissolved in an organic solvent. Examples of solid polymer electrolytes include ion-conducting polymers prepared from monomers containing atoms with lone pairs of electrons available for the lithium ions of the electrolyte salt to attach and migrate during conduction, such as polyvinylidene fluoride (PVDF) or copolymers of chlorides or their derivatives, poly(chlorotrifluoroethylene), poly(ethylene-chlorotrifluoroethylene), or poly(fluorinated ethylene propylene), polyethylene oxide (PEO) and oxymethylene-linked PEO, PEO-PPO-PEO crosslinked with trifunctional urethane, poly(bis(methoxy-ethoxy)-2-methyl-2-propanol), and poly(ethylene-propylene-2-methyl-2-propanol). The solid polymer electrolyte may be selected from the group consisting of methyl-ethoxide)-phosphazene (MEEP), triol-type PEO crosslinked with difunctional urethane, poly((oligo)oxyethylene) methacrylate-co-alkali metal methacrylate, polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polymethylacrylonitrile (PMAN), polysiloxanes and their copolymers and derivatives, acrylate-based polymers, other similar solvent-free polymers, combinations of the aforementioned polymers condensed or crosslinked to form different polymers, and physical mixtures of any of the aforementioned polymers. Other low-conductivity polymers that can be used in combination with the above polymers to improve the strength of thin laminates include polyester (PET), polypropylene (PP), polyethylene naphthalate (PEN), polyvinylidene fluoride (PVDF), polycarbonate (PC), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE). Such solid polymer electrolytes may further contain small amounts of organic solvents as listed above. The polymer electrolyte may be an ionic liquid polymer.Such polymer-based electrolytes can be coated using any number of conventional methods, such as curtain coating, slot coating, spin coating, inkjet coating, spray coating or other suitable methods.

[0104] Additives may be included in the electrolyte to perform various functions. For example, additives such as polymerizable compounds with unsaturated double bonds may be added to stabilize or modify the SEI. Certain amine or borate compounds can act as cathodic protectants. Lewis acids may be added to enhance the PF6 - Fluorine-containing anions such as ##STR1## can be stabilized. Safety protection agents include those for overcharge protection, such as anisole, or flame retardants, such as alkyl phosphates.

[0105] In some embodiments, the solid electrolyte may be vapor-deposited, solution-coated, fused-coated, or a combination thereof. Whether vapor-deposited or coated from a solution or melt, embodiments of the present disclosure offer advantages over nanostructured devices. With vapor-deposited solid electrolytes, the presently disclosed anodes do not suffer from the physical "shadowing" problem that nanostructured or microstructured devices do. Shadowing results in non-uniform electrolyte deposition. The anodes disclosed herein generally do not have high-aspect ratio structures, as discussed above, resulting in no or reduced shadowing effects. Vapor-deposited solid electrolytes can be uniformly and quickly deposited on the presently disclosed anodes without relying on slow atomic layer or other conformal coating methods. With solution- or fused-deposited solid electrolytes, the presently disclosed anodes may be more robust against stresses and shear forces induced by coating operations. High-aspect ratio nanostructures or microstructures are susceptible to damage from such forces.

[0106] In some embodiments, the original, uncycled anode may undergo structural or chemical changes during electrochemical charge / discharge, for example, from normal battery use or from a previous "electrochemical formation step." As known in the art, the electrochemical formation step is typically used to form the initial SEI layer and involves relatively mild conditions of low current and limited voltage. Modified anodes partially prepared from such electrochemical charge / discharge cycles may still have superior performance characteristics despite such structural and / or chemical changes compared to the original, uncycled anode. [Example]

[0107] For Anodes 1-10, current collectors with a metal oxide layer (nickel oxide) on a conductive metal layer (nickel) were prepared by placing nickel foil in a muffle furnace (heated air), holding the foil at 700 °C for 30 minutes, and then cooling to room temperature. The thickness of the metal oxide was approximately 0.7 to 1.2 microns.

[0108] Anode 1 (without auxiliary layer) The current collector was placed in a high-density plasma chemical vapor deposition tool (HDPECVD) using silane gas as the source of silicon and argon carrier gas. Approximately 0.8 mg / cm 2 Amorphous silicon was deposited on one side of the nickel foil with a total loading of 0.05 to form a continuous porous lithium storage layer with a thickness of about 4 μm.

[0109] Anode 2 (Si3N4 auxiliary layer) Anode 2 was prepared in the same manner as Anode 1, except that a nitrogen source was added to the silane / Ar gas mixture and a 30 nm substantially stoichiometric silicon nitride was deposited to form a sublayer on top of the continuous porous lithium reservoir layer (a-Si) before removal from the HDPECVD tool.

[0110] Anode 3 (Si3N4 / TiO2 auxiliary layer) Anode 3 was prepared in the same manner as Anode 1, except that before removal from the HDPECVD tool, a nitrogen source was added to the silane / Ar gas mixture and 15 nm of substantially stoichiometric silicon nitride was deposited to form a first sublayer on the continuous porous lithium reservoir layer (a-Si). The anode was then transferred to an ALD tool, and 6 nm of titanium dioxide was deposited on the first sublayer to form a second sublayer.

[0111] half battery Half-cells were constructed using a 1.27 cm diameter punch for each anode. Lithium metal served as a counter electrode, separated from the test anode using a Celgard™ separator. The electrolyte contained: a) 88 wt.% 1.0 M LiPF6 in a 3:7 EC:EMC (weight ratio); b) 10 wt.% FEC; and c) 2 wt.% VC. The anodes were first subjected to an electrochemical formation step. As known in the art, the electrochemical formation step is used to form an initial SEI layer. To avoid overstressing the anode, relatively gentle conditions of low current and / or limited voltage can be used. For example, the electrochemical formation can involve several cycles at a low C-rate ranging from C / 20 to C / 5. Silicon, when used in lithium-ion batteries, has a theoretical charge capacity of approximately 3600 mAh / g, but cycle life has been found to be significantly improved if only a portion of the total capacity is used. Unless otherwise specified, performance cycles were set to use approximately one-third of the total capacity, or approximately 1200 mAh / g ("Capacity Rating"). Unless otherwise specified, performance cycle protocols generally included a 3C charge and a C / 3 discharge to approximately 20% state of charge. A 10-minute rest was allowed between charge / discharge cycles.

[0112] A plot of discharge capacity as a function of cycle number is shown in Figure 11. All anodes have good cycle life, even under these rapid charge conditions (3C). Anode 1 lasted approximately 300 cycles before showing signs of fade. By adding an auxiliary layer, the cycle life of Anode 2 was extended to approximately 400 cycles before signs of fade (an increase of approximately 30%), with only a small loss of overall starting capacity (approximately 10%). Furthermore, when this occurred, the fade rate was substantially lower than that of Anode 1. By adding the first and second auxiliary layers, the cycle life of Anode 3 was extended to nearly 500 cycles before signs of fade (an increase of approximately 60% relative to Anode 1), with an even smaller loss of overall capacity (approximately 5%). Furthermore, when this occurred, the fade rate was substantially lower than that of Anode 1. The cycle lives of Anodes 1-3, along with those of other anodes, for cycling to 80% of their initial charge capacities are shown in Table 1 below.

[0113] Additional anodes were prepared and tested in half cells in the same manner as above.

[0114] Anode 4 (without auxiliary layer) Anode 4 was substantially the same as Anode 1. The continuous porous lithium storage layer was about 4 μm thick and about 1.8 to 2.0 g / cm 3 The amorphous silicon had a density in the range of 0.1 to 0.5.

[0115] Anode 5 (Si3N4 / Al2O3 auxiliary layer) Anode 5 was essentially the same as Anode 4, except that before removal from the HDPECVD tool, a nitrogen source was added to the silane / Ar gas mixture, and 15 nm of substantially stoichiometric silicon nitride was deposited to form a first auxiliary layer on the continuous porous lithium reservoir layer (a-Si). The anode was then transferred to an ALD tool, and 6 nm of aluminum oxide was deposited on the silicon nitride. Subsequent testing showed that this cell did not survive the electrochemical formation step. Therefore, in some embodiments, when using a silicon nitride first auxiliary layer, it may be preferable not to use aluminum oxide as a second auxiliary layer. Surprisingly, aluminum oxide did not perform well, and titanium dioxide appears to be a better second auxiliary layer in this case.

[0116] Anode 6 (TiO2 / Al2O3 auxiliary layer) Anode 6 was similar to Anode 4, except that multiple auxiliary layers were deposited by ALD. The first auxiliary layer comprised 10 nm of titanium dioxide, and the second auxiliary layer comprised 4 nm of aluminum oxide. As shown in Table 1 below, the cycle life is substantially improved over Anode 4, which does not have an auxiliary layer.

[0117] Anode 7 (Al2O3 / TiO2 auxiliary layer) Anode 6 was similar to Anode 4, except that multiple auxiliary layers were deposited by ALD. The first auxiliary layer comprised 10 nm of aluminum oxide, and the second auxiliary layer comprised 4 nm of titanium dioxide. As shown in Table 1, the cycle life was acceptable, but not as good as Anode 4, which had no auxiliary layers, and much lower than Anode 5, which had the opposite auxiliary layer structure. While there may be other reasons for using the structure of Anode 7, in some embodiments, when using multiple metal oxide auxiliary layers, it may be preferable not to use aluminum oxide as the first auxiliary layer. Surprisingly, aluminum oxide did not perform well, and titanium dioxide appears to be a better first auxiliary layer in this case.

[0118] Anode 8 (60 nm SiO2 auxiliary layer) Anode 8 was similar to Anode 4, except that prior to removal from the HDPECVD tool, oxygen gas was added to the silane / Ar gas mixture and a 60 nm substantially stoichiometric silicon dioxide was deposited to form a sublayer on top of the continuous porous lithium reservoir layer (a-Si). As shown in Table 1, silicon dioxide causes a decrease in surface charge capacity but can significantly improve cycle life. By increasing the capacity rating to 1600 mAh / g, the surface charge capacity can be restored similar to Anode 4, and cycle life is still extended.

[0119] Anode 9 (120 nm SiO2 auxiliary layer) Anode 9 was similar to Anode 8, except that 120 nm of substantially stoichiometric silicon dioxide was deposited. As shown in Table 1, silicon dioxide causes a decrease in surface charge capacity but can significantly improve cycle life. By increasing the capacity rating to 1600 mAh / g, the surface charge capacity can be restored to a similar level to Anode 4, and cycle life is still extended.

[0120] Anode 10 (SiOx lithium storage sublayer) Anode 10 was similar to Anode 4, except that prior to removal from the HDPECVD tool, oxygen gas was added to the gas mixture to deposit approximately 250 nm of substoichiometric silicon oxide to form a lithium storage sublayer on the amorphous silicon. While the stoichiometry of the SiOx sublayer is not known with certainty, the oxygen gas flow rate was set to only about 12% of the rate used to create substantially stoichiometric silicon dioxide. The total thickness and density of the combined a-Si and SiOx sublayers were approximately 4.5 μm and 2.1 g / cm, respectively. 3 As shown in Table 1, Anode 10 has an improved cycle life compared to Anode 4, which does not have an SiOx sublayer. Note that the cycle life in Table 1 is an average of two cycles.

[0121] [Table 1]

[0122] Anode 11 A different current collector was prepared for anode 11. Specifically, a 50 nm TiO2 (metal oxide) layer was deposited on a conductive commercial copper foil by ALD. Silicon was deposited on the TiO2 using an Oxford Plasmalabs System 100 PECVD tool operated at about 300 °C with about 225 W RF power for 50 minutes. The deposition gas was a mixture of silane and argon, along with a boron-containing dopant gas, with a gas flow ratio of about 1:11, respectively. Hydrogen gas was not used. The deposition gas was about 1.7 g / cm3. 3 An adherent boron-doped amorphous silicon film was deposited to a thickness of approximately 14 μm with a density of 0.01 μm.

[0123] Anodes 11A to 11E After silicon deposition, samples of anode 11 were transferred to a tube furnace under argon and heat treated for various times and temperatures to form anodes 11A-11E shown in Table 2 below.

[0124] Anodes 11 and 11A-11E were tested in half cells as described above, except that the cell punch size was reduced for greater charge capacity. At the end of the formation cycle, the total charge capacity was measured electrochemically along with the final formation cycle current efficiency. These data are also shown in Table 2.

[0125] [Table 2]

[0126] While all anodes have very high surface charge capacities, the data in Table 2 show that anode heat treatment appears to unlock some additional charge capacity when treated at 475°C or 575°C (approximately 8%-15% more than anode 11 without heat treatment). In lithium-ion batteries, such improvements are commercially important and can be used to increase the charge capacity of the cell, to reduce the weight and / or volume of the cell while maintaining the charge capacity of the cell, to extend cycle life by lowering the rated capacity while maintaining the total charge capacity of the cell, or some combination.

[0127] The performance of anodes 11 and 11A-11E under cycling conditions was tested at C / 3, 1C, and 3.2C charges (all C / 3 discharges) as previously described. The anodes were rated at approximately 1100 mAh / g capacity. At C / 3 and 1C charge schedules, the cells achieved a capacity of 2.0 mAh / cm. 2 The cell was cycled to a target initial surface charge capacity of 1.6 mAh / cm. The high charge rate 3.2C test was completed at a charge current of 3.2C with a total time limit of 15 minutes. This is a common fast charge test used in the industry (see Battery Test Manual for Electric Vehicles, Jon P. Christophersen, June 2015, INL / EXT-15-34184 Revision 3, page 5). When the cell completes the full constant current charge, it will achieve 3.2 x 0.25 or 80% of its rated capacity, in this case 1.6 mAh / cm. 2 The cells that reached the charge voltage limit before 15 minutes were charged both galvanostatically and potently. The latter portion of the charge resulted in the cells achieving less than 80% of their rated capacity. None of these anodes completed the cycle or reached 80% of their initial charge capacity (except for anode 11A, which did so at approximately 400 cycles), but the plots are shown in Figure 12 (C / 3 charge), Figure 13 (1C), and Figure 14 (3.2C). The test cells were not all started at the same time and are therefore at various stages of cycling.

[0128] Inspection of Figure 12 shows that there is still no substantial difference between the anodes at C / 3 charge.

[0129] Figure 13 reveals a degradation in the performance of anode 11 at cycles 25 to 60 relative to all of the other anodes. Anode 11 also appears to exhibit some cycle fade beginning at approximately cycle 225. Two heat-treated anodes, which at this writing had reached at least 230 cycles (11A at 276 cycles and 11B at 237 cycles), did not exhibit such fade. Thus, at charge rates faster than C / 3, the heat-treated anodes appear to exhibit improved cycle life.

[0130] FIG. 14 shows that the non-heat-treated anode 11 never reaches 80% state of charge at 3.2 C, i.e., 1.6 mAh / cm 2 Instead, the anode 11 is about 1.25 mAh / cm 2 The results show that the 15-minute constant current charge does not reach 80% state of charge for at least several cycles due to their more resistive characteristics. 2 The fact that the charge rates were close to the limiting capacity of 100 C indicates that the majority of their charging remained constant current. We hypothesize that the combination of a very fast charge of 3.2 C combined with a high-capacity silicon anode (for Anodes 1-10) may have introduced some resistance to electron flow or lithium diffusion. However, note that all of the heat-treated samples, Anodes 11A-11E, were much closer to the target charge capacity than the unheat-treated Anode 11. Therefore, it appears that anode heat treatment can be used to improve the fast-charging characteristics of anodes.

[0131] Despite industry support for micro- or nanostructured silicon or other lithium storage materials, the present disclosure has discovered that highly effective anodes can be formed without such features. While the present anodes have been described with reference to batteries, in some embodiments, the present anodes can be used in hybrid capacitor devices. Compared to comparable micro- or nanostructured anodes, the presently disclosed anodes can have one or more of at least the following unexpected advantages: comparable or improved stability at aggressive charge rates of ≥ 1 C, higher total surface charge capacity, higher gravimetric charge capacity, higher volumetric charge capacity, improved physical durability, simplified manufacturing processes, and / or more reproducible manufacturing processes.

[0132] Although the present anodes have been described with reference to batteries, in some embodiments, the present anodes can be used in hybrid lithium-ion capacitor devices. Some non-limiting representative embodiments are listed below. 1. An anode for an energy storage device, comprising: a current collector including a metal oxide layer; and An anode comprising a continuous porous lithium reservoir layer overlying a metal oxide layer. 2. The anode of embodiment 1, further comprising a first auxiliary layer covering the continuous porous lithium storage layer, the first auxiliary layer comprising silicon nitride, silicon dioxide, silicon oxynitride, or a first metal compound. 3. The anode of embodiment 2, wherein the first auxiliary layer comprises silicon nitride having a thickness in the range of about 2 nm to about 50 nm. 4. The anode of embodiment 2, wherein the first auxiliary layer comprises silicon dioxide and has a thickness ranging from about 10 nm to about 150 nm. 5. The anode of embodiment 2, wherein the first auxiliary layer comprises a first metal compound selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides, and has a thickness of about 2 nm to about 50 nm. 6. The anode of embodiment 5, wherein the first metal compound is a transition metal oxide. 7. The anode of embodiment 5, wherein the first metal compound is titanium dioxide. 8. The anode of any one of embodiments 2 to 7, further comprising a second auxiliary layer characterized by a composition different from the first auxiliary layer composition and comprising silicon dioxide, silicon nitride, silicon oxynitride, or a second metal compound. 9. The anode of embodiment 8, wherein the second metal compound comprises a metal oxide, a metal nitride, or a metal oxynitride, and the second auxiliary layer has a thickness in the range of about 2 nm to about 50 nm. 10. The anode of embodiment 9, wherein the first auxiliary layer comprises silicon nitride and the second auxiliary layer comprises titanium dioxide. 11. (i) the first substrate comprises substantially stoichiometric silicon nitride and has a thickness in the range of about 2 nm to about 50 nm; and (ii) the second auxiliary layer comprises titanium dioxide and has a thickness in the range of about 2 nm to about 20 nm; 11. An anode as described in embodiment 10. 12. The anode of embodiment 8, wherein the first auxiliary layer comprises titanium dioxide and has a thickness of about 2 nm to about 20 nm. 13. The anode of embodiment 12, wherein the second auxiliary layer comprises aluminum oxide having a thickness of about 2 nm to about 20 nm. 14. (i) The first auxiliary layer does not contain aluminum oxide; (ii) when the first auxiliary layer comprises substantially stoichiometric silicon nitride, the second auxiliary layer does not comprise aluminum oxide; 9. The anode of embodiment 8. 15. The anode of embodiment 8, wherein the second metal compound is a lithium-containing material. 16. The anode of embodiment 15, wherein the lithium-containing material comprises lithium phosphate nitride, lithium phosphate, lithium aluminum oxide, or lithium lanthanum titanate. 17. The anode of embodiment 8, wherein the second auxiliary layer comprises a metal cone. 18. The anode according to any one of embodiments 15 to 17, wherein the second auxiliary layer has a thickness in the range of about 5 nm to about 150 nm. 19. The anode of any one of embodiments 8 to 18, further comprising one or more additional auxiliary layers covering the first and second auxiliary layers, at least one of the additional layers comprising a metal oxide, a metal nitride, a metal oxynitride, a lithium-containing material, or a metal cone. 20. The anode of any one of embodiments 1-19, wherein the continuous porous lithium storage layer comprises a first lithium storage sublayer overlying the metal oxide layer and a second lithium storage sublayer overlying the first lithium storage sublayer, the first lithium storage sublayer being characterized by a different composition than the second lithium storage sublayer. 21. The anode of embodiment 20, wherein each lithium storage sublayer has a composition comprising silicon, germanium, or a combination thereof. 22. The anode of embodiment 20 or 21, wherein the first or second lithium storage sublayer comprises silicon and oxygen, and the ratio of oxygen to silicon is in the range of 0.02 to 0.95. 23. The anode of embodiment 20 or 21, wherein i) the second lithium storage sublayer comprises silicon and oxygen, and the ratio of oxygen to silicon is in the range of 0.02 to 0.95; ii) the first lithium storage sublayer comprises a higher atomic % of silicon and a lower atomic % of oxygen than the second lithium storage sublayer; and iii) the thickness of the second lithium storage sublayer is less than the thickness of the first lithium storage sublayer. 24. The anode of any one of embodiments 20-22, wherein the first or second lithium storage sublayer comprises silicon and nitrogen, and the ratio of nitrogen to silicon is in the range of 0.02 to 0.95. 25. The anode of any one of embodiments 20-22, wherein the first or second lithium storage sublayer comprises silicon, oxygen, and nitrogen, and the ratio of total oxygen and nitrogen atoms to silicon is within the range of 0.02 to 0.95. 26. A continuous porous lithium storage layer is i) silicon and oxygen, with the ratio of oxygen atoms to silicon atoms ranging from 0.02 to 0.95; ii) silicon and nitrogen, with the ratio of nitrogen atoms to silicon atoms ranging from 0.02 to 0.95; or iii) silicon, oxygen and nitrogen, wherein the ratio of the sum of oxygen atoms and nitrogen atoms to silicon atoms is within the range of 0.02 to 0.95; 20. The anode of any one of embodiments 1 to 19, comprising: 27. The anode of any one of embodiments 1-26, wherein the metal oxide layer comprises an oxide of an alkali metal or alkaline earth metal. 28. The anode of embodiment 27, wherein the metal oxide layer comprises an oxide of lithium. 29. The anode of any one of embodiments 1 to 28, wherein the metal oxide layer comprises an oxide of a transition metal. 30. The anode of embodiment 29, wherein the metal oxide layer comprises an oxide of nickel or an oxide of titanium. 31. The anode of any one of embodiments 1 to 30, wherein the metal oxide layer further comprises a metal hydroxide. 32. The anode of embodiment 31, wherein the metal oxide layer has a ratio of oxygen atoms in the form of hydroxide to oxide of less than 0.25. 33. The anode of any one of embodiments 1 to 32, wherein the metal oxide layer has an average thickness in the range of about 0.010 μm to about 1.0 μm. 34. The anode of any one of embodiments 1-33, wherein the continuous porous lithium storage layer has a total content of at least 40 atomic % silicon, germanium, or a combination thereof. 35. A continuous porous lithium storage layer has a capacity of approximately 1.1 g / cm 3 ~2.2g / cm 3 35. The anode of any one of embodiments 1-34, comprising at least 85 atomic % amorphous silicon having a density in the range of 36. The anode of any one of embodiments 1 to 35, wherein the continuous porous lithium storage layer has a thickness of at least 3 μm. 37. The anode of any one of embodiments 1 to 37, wherein the continuous porous lithium storage layer has a thickness in the range of about 7 μm to about 30 μm. 38. The anode of any one of embodiments 1 to 37, wherein the continuous porous lithium storage layer is substantially free of nanostructures. 39. The anode of any one of embodiments 1-38, wherein the continuous, porous lithium storage layer comprises less than 1% by weight of a carbon-based binder. 40. The anode of any one of embodiments 1-39, wherein the anode has a total reflectance measured at 550 nm at the top surface of the anode of at least 10%. 41. The anode of any one of embodiments 1 to 40, wherein the continuous porous lithium storage layer comprises metal from the metal oxide layer in an atomic percent range of about 0.05% to about 5%. 42. The anode of any one of embodiments 1-41, wherein the current collector further comprises a conductive layer, and the metal oxide layer is interposed between the conductive layer and the continuous porous lithium storage layer. 43. The anode of embodiment 42, wherein the conductive layer comprises stainless steel, titanium, nickel, copper, conductive carbon, or a combination thereof. 44. The anode of embodiment 43, wherein the continuous, porous lithium storage layer comprises metal from the conductive layer in an atomic percent range of about 0.05% to about 5%. 45. A battery comprising an anode according to any one of embodiments 1 to 44 and a cathode. 46. ​​The battery of embodiment 45, further comprising one or more compression members configured to apply pressure to the anode in a direction toward the cathode, or configured to apply pressure to the cathode in a direction toward the anode, or both. 47. The lithium-ion battery of embodiment 45 or 46, wherein the anode is prelithiated and the cathode comprises sulfur, selenium, or both sulfur and selenium. 48. The lithium-ion battery of embodiment 47, wherein the cathode further comprises a first carbon material. 49. A lithium-ion battery according to embodiment 48, wherein the cathode further comprises carbon nanotubes. 50. A method of making an anode for use in an energy storage device, comprising: providing a current collector comprising a conductive layer and a metal oxide layer overlying the conductive layer, the metal oxide layer having an average thickness of at least 0.01 μm; depositing a continuous porous lithium storage layer on the metal oxide layer by a CVD process; A method comprising: 51. The step of providing a current collector comprises: i) depositing a metal oxide precursor composition over a conductive layer to form a deposited metal oxide precursor composition; and ii) forming a metal oxide layer using the deposited metal oxide precursor composition; 51. The method of embodiment 50, comprising: 52. The method of embodiment 51, wherein the metal oxide precursor composition comprises a sol-gel, a metal carbonate, a metal acetate, a metal organic acetate, a metal hydroxide, a metal oxide dispersion, or a combination thereof. 53. The method of embodiment 52, wherein forming the metal oxide layer comprises heat-treating the deposited metal oxide precursor composition. 54. The method of embodiment 53, wherein the heat-treating step comprises exposing the deposited metal oxide precursor composition to a temperature in the range of 50°C to 250°C, optionally for a time in the range of 0.1 to 120 minutes. 55. The method of any of embodiments 51-54, wherein the step of forming a metal oxide layer comprises exposing the deposited metal oxide precursor composition to a pressure in the range of 0.1 to 100 torr, optionally for a time in the range of 0.1 to 120 minutes. 56. The method of embodiment 51, wherein the metal oxide precursor composition comprises metal-containing particles. 57. The method of embodiment 56, wherein the step of forming a metal oxide layer comprises oxidizing metal-containing particles. 58. The method of embodiment 57, wherein oxidizing comprises exposing the metal particles to an oxygen-containing gas or a solution comprising a chemical oxidant. 59. The method of any of embodiments 50-58, further comprising depositing lithium metal on the metal oxide layer before depositing the continuous porous lithium storage layer. 60. The method of embodiment 59, wherein the lithium metal is deposited by evaporation, electron beam, or sputtering. 61. The method of embodiment 59 or 60, wherein the ratio of deposited lithium metal atoms to oxygen atoms in the metal oxide layer is in the range of 0.05 to 1.0. 62. The method of any of embodiments 59-61, wherein the amount of deposited lithium metal is in the range of 2% to 50% of the maximum lithium areal capacity of the continuous porous lithium storage layer. 63. The method of any of embodiments 1-62, further comprising forming a lithiated storage layer by incorporating lithium into the continuous porous lithium storage layer prior to the first electrochemical cycle when the anode is assembled into an energy storage device. 64. The method of embodiment 63, wherein the lithium is incorporated prior to assembly of the energy storage device. 65. The method of embodiment 63 or 64, wherein incorporating lithium comprises depositing a lithiated material onto a continuous porous lithium storage layer. 66. The method of embodiment 65, wherein the lithiated material comprises a reducible lithium compound, lithium metal, or stabilized lithium metal powder. 67. The method of embodiment 65 or 66, further comprising applying heat or pressure to the anode during or after deposition of the lithiated material. 68. The method of embodiment 63 or 64, wherein the step of incorporating lithium comprises contacting the anode with a lithiated material provided as a coating on a lithium transfer substrate. 69. The method of embodiment 68, wherein the lithiated material comprises a reducible lithium compound, lithium metal, or stabilized lithium metal powder. 70. The method of embodiment 68 or 69, further comprising applying heat or pressure to the anode during or after contacting. 71. The method of any one of embodiments 68-70, wherein the lithium transfer substrate functions as a current separator in the assembled battery. 72. The method of embodiment 63 or 64, wherein the step of incorporating lithium comprises contacting the continuous porous lithium storage layer with a solution comprising a reducible lithium organic compound. 73. The method of embodiment 63 or 64, wherein lithium is incorporated electrochemically. 74. The method of any of embodiments 63-73, further comprising forming a sublayer on the continuous porous lithium storage layer before forming the lithiated storage layer. 75. The method of embodiment 74, wherein the auxiliary layer comprises silicon nitride, a metal oxide, a metal nitride, or a metal oxynitride. 76. The method of any of embodiments 63-75, further comprising heat treating the continuous porous lithium storage layer during incorporation, after incorporation, or both during and after incorporation. 77. The step of forming a lithiated storage layer comprises: (a) depositing a lithium metal layer on a continuous porous lithium storage layer; and (b) depositing a lithium metal layer followed by depositing a lithium ion conducting layer; 65. The method of embodiment 64, comprising: 78. The method of claim 77, further comprising the step of: i) applying heat to the anode between steps (a) and (b), ii) after step (b), or iii) during both (i) and (ii). 79. The method of embodiment 77 or 78, wherein the lithium ion conducting layer comprises at least one of a lithium-containing material, a metal oxide, or a metal cone. 80. The method of any of embodiments 77-79, wherein the lithium ion conducting layer comprises at least one of lithium phosphorus nitrite (LIPON), lithium phosphate, lithium aluminum oxide, lithium lanthanum titanate, alcone, or zirconium. 81. The method of any one of embodiments 50-80, further comprising treating the anode with a reducing agent before battery assembly. 82. The method of embodiment 81, wherein the reducing agent has an electrochemical potential sufficient to reduce at least a portion of the metal oxide layer. 83. The method of embodiment 81 or 82, wherein the reducing agent comprises an inorganic hydride, a substituted or unsubstituted borohydride, an amine-borane, or an anionic organic aromatic compound. 84. The method of any of embodiments 81-83, wherein treating the anode with a reducing agent comprises treating the anode with a non-aqueous solvent containing the reducing agent. 85. The method of any one of embodiments 50-84, further comprising heat treating the anode after depositing the continuous porous lithium storage layer and before battery assembly. 86. The method of embodiment 85, wherein the heat-treating step comprises heating the anode to a temperature in the range of 50°C to 600°C for a time in the range of 0.1 minutes to 120 minutes. 87. The method of embodiment 85 or 86, wherein the heat treating step is carried out in an environment having an oxygen and moisture pressure each less than 1 Torr. 88. The method of embodiment 85 or 86, wherein the heat treating step is carried out in an environment having oxygen and moisture pressures each less than 0.1 Torr. 89. The method of any of embodiments 85-88, wherein the heat-treating step comprises heating the anode to a temperature in the range of 350°C to 600°C for a time in the range of 0.1 minutes to 30 minutes. 90. The method of any one of embodiments 85-89, wherein the metal oxide layer comprises an oxide of nickel or an oxide of titanium. 91. The method of any one of embodiments 85-89, wherein the conductive layer comprises copper and the metal oxide layer comprises an oxide of titanium having a thickness in the range of 0.01 μm to 0.20 μm. 92. The method of any of embodiments 85-91, wherein the heat-treating step comprises moving the anode to an oven, exposing the anode to an IR radiation source, or contacting the anode with a heated surface. 93. The method of any one of embodiments 85-92, wherein the heat treating step increases the electrical conductivity of the continuous porous lithium storage layer. 94. The method of any one of embodiments 85-93, wherein the heat treating step increases the adhesion of the continuous porous lithium storage layer to the current collector. 95. The method of any one of embodiments 85-94, wherein the heat-treating step forms an anode in a lithium-ion battery cell that has a higher charge capacity than a comparable anode that does not undergo the heat-treating step. 96. The method of any one of embodiments 85-95, wherein the heat-treating step forms an anode in a lithium-ion battery cell that is capable of faster charging than a comparable anode that is not subjected to the heat-treating step. 97. The method of any one of embodiments 45-96, wherein the CVD process is a PECVD process. 98. The method of embodiment 97, wherein the continuous porous lithium storage layer comprises a total content of at least 40 atomic % silicon, germanium, or a combination thereof. 99. The continuous porous lithium storage layer has a density of approximately 1.1 g / cm 3 ~2.2g / cm 3 99. The method of embodiment 97 or 98, comprising at least 85 atomic % amorphous silicon having a density in the range of 100. The anode of any one of embodiments 50-99, wherein the continuous porous lithium storage layer has a thickness of at least 3 μm. 101. The anode of any one of embodiments 50-100, wherein the continuous porous lithium storage layer has a thickness in the range of about 7 μm to about 30 μm. 102. The method of any of embodiments 50-101, wherein the PECVD process comprises using silane gas and optionally hydrogen gas, and the ratio of hydrogen gas flow to silane gas flow is in the range of 0-2. 103. The method of any one of embodiments 50-102, wherein the PECVD process further comprises using a doping gas to dope the continuous porous lithium storage layer, and the ratio of the doping gas flow to the silane gas flow is in the range of 0.001 to 0.05. 104. The method of embodiment 103, wherein the doping gas is borane or phosphine. 105. The method of any of embodiments 97-104, wherein the PECVD process is an expanding thermal plasma PECVD process or a hollow cathode tube PECVD process. 106. The method of any one of embodiments 97-105, wherein the PECVD process further comprises heating the current collector to a temperature in the range of 200°C to 600°C during at least a portion of the process. 107. The method of any of embodiments 97-106, further comprising, after depositing at least 50% of the continuous porous lithium storage layer, adding an oxygen source, a nitrogen source, or both, to the silane gas to form a lithium storage sub-layer or auxiliary layer comprising silicon nitride, silicon oxide, or silicon oxynitride. 108. The method of embodiment 107, wherein an auxiliary layer comprising silicon dioxide is formed having a thickness in the range of about 10 nm to about 150 nm. 109. The method of embodiment 107, wherein a sublayer comprising substantially stoichiometric silicon nitride is formed having a thickness in the range of about 2 nm to about 50 nm. 110. The method of any of embodiments 50-109, further comprising depositing one or more auxiliary layers, each comprising an independently selected metal compound. 111. The method of embodiment 110, wherein the metal compound is a metal oxide, a metal nitride, a metal oxynitride, a lithium-containing material, or a metal cone. 112. The method of any one of embodiments 50-111, wherein one or more of the depositing or heat treating steps are performed using a roll-to-roll manufacturing method. 113. A lithium-ion battery comprising an anode made according to any of embodiments 50-112 and a cathode. 114. A lithium-ion battery according to embodiment 113, wherein the anode comprises a lithiated storage layer and the cathode comprises sulfur, selenium, or both sulfur and selenium. 115. The lithium-ion battery of embodiment 114, wherein the cathode further comprises carbon nanotubes. 116. The lithium-ion battery of embodiment 114 or 115, wherein the lithiated storage layer contains lithium in the range of 50% to 100% of the theoretical lithium storage capacity of the continuous porous lithium storage layer. 117. A lithium ion battery comprising an anode and a cathode, wherein the anode is prepared in part by subjecting a non-cycling anode to at least one electrochemical charge / discharge cycle, and the non-cycling anode comprises: i) the anode described in any of embodiments 1-41, or an anode made according to any of embodiments 50-112.

[0133] In the foregoing description, for purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that particular embodiments may be practiced without some of these details or with additional details.

[0134] While several embodiments have been described, those skilled in the art will recognize that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. Moreover, certain well-known processes and elements have not been described to avoid unnecessarily obscuring the invention. Furthermore, the details of any particular embodiment are not always present in variations of that embodiment, and may be added to other embodiments.

[0135] Where a range of values ​​is presented, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range is also specifically disclosed, unless the context clearly dictates otherwise. Each smaller range between any stated or intervening value in a stated range and any other stated or intervening value within that stated range is encompassed. The upper and lower limits of these smaller ranges may independently be included or excluded, and each range whose limits are included in either, neither, or both of the smaller ranges is also encompassed within the invention, subject to any specifically excluded limits in the stated range. Where a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0136] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "method" includes a plurality of such methods; reference to a "layer" includes a reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth. The present invention has been described in detail herein for purposes of clarity and understanding. However, it will be understood that certain changes and modifications can be practiced within the scope of the appended claims.

[0137] All publications, patents, and patent applications cited herein are incorporated by reference in their entirety for all purposes. None is admitted to be prior art.

Claims

1. 1. An anode for an energy storage device, comprising: a current collector including a metal oxide layer; a continuous porous lithium storage layer overlying the metal oxide layer; the continuous porous lithium storage layer comprises a substoichiometric nitride of silicon and a total silicon content of at least 40 atomic percent; anode.

2. the substoichiometric nitride of silicon has a ratio of nitrogen atoms to silicon atoms in the range of 0.02 to 1.20; The anode of claim 1 .

3. The substoichiometric nitride of silicon has a ratio of nitrogen atoms to silicon atoms in the range of 0.02 to 0.

95. The anode of claim 1 .

4. The substoichiometric nitride of silicon has a ratio of nitrogen atoms to silicon atoms in the range of 0.02 to 0.

50. The anode of claim 1 .

5. The substoichiometric nitride of silicon has a ratio of nitrogen atoms to silicon atoms in the range of 0.10 to 0.

50. The anode of claim 1 .

6. The substoichiometric nitride of silicon has a ratio of nitrogen atoms to silicon atoms in the range of 0.02 to 0.

10. The anode of claim 1 .

7. the current collector further comprises a conductive layer; the metal oxide layer is interposed between the conductive layer and the continuous porous lithium storage layer; The anode of claim 1 .

8. the conductive layer comprises copper, nickel, titanium, or stainless steel; 8. The anode of claim 7.

9. the metal oxide layer has an average thickness of at least 0.005 μm; The anode of claim 1 .

10. the metal oxide layer comprises a transition metal oxide; The anode of claim 1 .

11. the continuous porous lithium storage layer comprises a total silicon content of at least 60 atomic percent; The anode of claim 1 .

12. Further comprising a substoichiometric oxide of silicon, wherein the ratio of the sum of nitrogen atoms and oxygen atoms to silicon atoms is in the range of 0.02 to 0.95; The anode of claim 1 .

13. The amount of nitride is provided as a function of the thickness of the continuous porous lithium storage layer. The anode of claim 1 .

14. the continuous porous lithium storage layer is deposited by a PECVD process; The anode of claim 1 .

15. 10. A method for manufacturing a semiconductor device comprising the anode of claim 1 , Lithium-ion battery.

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