Solid-state lithium-ion battery

Abstract

A lithium-ion battery cell includes a negative electrode including a porous lithium storage layer disposed on a negative current collector and a modification layer disposed on the lithium storage layer. The cell further includes a positive electrode having a positive active material layer in electrical contact with a positive current collector and a solid-state electrolyte (SSE) containing lithium ions interposed between the lithium storage layer and the positive active material. The lithium storage layer includes at least 40 atomic percent silicon, tin, germanium, or a combination thereof. The lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments each having an upper surface and sidewalls. The modification layer is disposed on the upper surfaces and at least partially along the sidewalls.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 615,911 entitled “Solid-state lithium-ion batteries”, filed on December 29, 2023, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] This disclosure relates to lithium-ion batteries and related energy storage devices. Background Technology

[0004] Silicon has been proposed for use in lithium-ion batteries to replace conventional carbon-based anodes, which have a storage capacity limited to ~370 mAh / g. Silicon readily alloys with lithium and exhibits a much higher theoretical storage capacity (~3600 mAh / g at room temperature) than carbon anodes. However, the insertion and extraction of lithium into the silicon matrix leads to significant volume expansion (>300%) and shrinkage. This causes the silicon to rapidly pulverize into small particles and become electrically disconnected from the current collector.

[0005] The expansion and contraction of silicon-containing anodes pose additional challenges to the manufacture of solid-state battery cells.

[0006] Despite the research into various approaches, silicon-based batteries, especially those using solid-state electrolytes, have not yet made a significant market impact due to unresolved issues. Summary of the Invention

[0007] Solid-state lithium-ion batteries based on silicon anodes that are still desirable are easy to manufacture, safer, more durable, have high charging capacity, are adaptable to fast charging, and have good cycle life.

[0008] According to embodiments of this disclosure, a lithium-ion battery cell includes a negative electrode comprising a porous lithium storage layer disposed on a negative electrode current collector and a modification layer disposed on the lithium storage layer. The cell further includes a positive electrode having a positive electrode active material layer in electrical contact with a positive electrode current collector and a lithium-ion-containing solid electrolyte (SSE) between the lithium storage layer and the positive electrode active material. The lithium storage layer comprises at least 40 atomic percent silicon, tin, germanium, or combinations thereof. The lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments, each having an upper surface and sidewalls. The modification layer is disposed on the upper surface and at least partially along the sidewalls. Attached Figure Description

[0009] Figure 1A This is a cross-sectional view of a non-limiting example of the negative electrode.

[0010] Figure 1B It corresponds to Figure 1A The cross-sectional view of the dashed circle B.

[0011] Figure 1C This is a cross-sectional view of a non-limiting example of a lithium-ion battery (LIB) cell.

[0012] Figure 1D It corresponds to Figure 1C The cross-sectional view of the dashed circle D.

[0013] Figure 1E This is a top view of a non-limiting example of a segmented lithium storage layer. Detailed Implementation

[0014] It should be understood that the accompanying drawings are for illustrative purposes and may not be to scale. Terms such as “cover” or “on top of” include, but do not necessarily require, direct contact (unless such direct contact is indicated or explicitly required for functionality). In this document, “average” may mean, median, or mode, and “average thickness” may be based on at least three measurements. Further details of certain embodiments of this application can be found in U.S. Patent Application Publication No. 2019 / 0267631, U.S. Patent Application Publication No. 2020 / 0411851, U.S. Patent Application Publication No. 2021 / 0050584, U.S. Patent Application Publication No. 2021 / 0057733, U.S. Patent Application Publication No. 2021 / 0057757, U.S. Patent Application Publication No. 2021 / 0057755, U.S. Patent Application Publication No. 2021 / 0066702, U.S. Patent Application Publication No. 2023 / 0343968, U.S. Patent Application Publication No. 2023 / 0142782, PCT International Publication No. WO2023 / 113813, and U.S. Patent Application Publication No. The contents of the following documents are found in 2022 / 0344627, PCT International Publication No. WO2023 / 129408, PCT International Publication No. WO2023 / 239599, PCT International Publication No. WO2024 / 058845, PCT International Publication No. WO2024 / 173383 and PCT International Publication No. WO2024 / 173390, and are incorporated herein by reference for all purposes.

[0015] The lithium-ion battery (LIB) disclosed herein may include a negative electrode, a positive electrode, and a solid electrolyte (“SSE”) between the negative and positive electrodes. The negative electrode includes a lithium storage layer, which in some cases may include multiple lithium storage layer segments. In some cases, such segments may be silicon-containing lithium storage segments. In some preferred embodiments, the SSE may be based on a solid sulfide material. As discussed elsewhere, in some cases, a lithium storage layer, such as a silicon-containing lithium storage layer, may be included as a modification layer on the surface of the lithium storage layer and between the SSE and the lithium storage layer. In some instances, the surface of the silicon-containing lithium storage layer may be modified by a treatment that may not necessarily form a continuous discrete layer, but still alter the surface properties of the lithium storage layer, as discussed elsewhere herein.

[0016] Figure 1A This is a schematic cross-sectional view of a non-limiting example of a negative electrode 100. The negative electrode 100 includes segmented lithium storage layers 107, comprising a plurality of lithium storage layer segments 107-1, 107-2, 107-3, and 107-4 defined by gaps or discontinuities 117. In some embodiments, the discontinuities may extend through some or all of the lithium storage layers in a direction generally orthogonal to the current collector surface, for example, within an orthogonal 30° range. In a SEM cross-section, the discontinuities may appear as cracks or fissures between the segments. Although shown as straight lines, the discontinuities 117 may appear as curved lines. A complete discontinuity may occur when there is no physical contact between adjacent segments. In some embodiments, a segment may have partial physical contact with adjacent segments, but the connectivity along the discontinuity may be weaker than the connectivity of the lithium storage material within the segment. That is, the discontinuity may be localized. Partial discontinuities may include bridging regions corresponding to locations where the lithium storage material connects one segment to another. Partial physical contact may include spaced segments having a segment thickness of less than 50%, 40%, 30%, 20%, or 10% physical contact. The negative electrode 100 includes a current collector 101, which may include a conductive layer 103 and a surface layer 105 optionally located between the conductive layer 103 and the segmented lithium storage layer 107.

[0017] The segmented lithium storage layer can be characterized by its average lateral width LW and average thickness T. (See again...) Figure 1A As an example, the lithium storage layer segment 107-3 along the xy plane has a lateral width LW. The average lateral width LW of this segment can correspond to the average of at least two measurements taken along the x-axis from one end of the segment to the other at different z-axis locations. Similarly, the average thickness T of this segment can correspond to the average of at least two measurements taken along the z-axis from the current collector to the top of the lithium storage layer (or, if present, to the top of the modified layer 108) at different x-axis locations.

[0018] In some cases, the negative electrode 100 having lithium storage layer segments can be formed directly during PVD or CVD (preferably PECVD) deposition of the lithium storage layer material. For example, the properties of the current collector can cause such segmentation. For example, the presence of grooves, ridges, dendrites, or patterned surface layers can easily lead to discontinuities during PVD or CVD deposition. Deposition conditions can also affect the development of such discontinuities. In some instances, the lithium storage layer may comprise silicon, germanium, tin, or alloys thereof. In some instances, the lithium storage layer is a silicon-containing lithium storage layer comprising at least 40 atomic percent silicon, alternatively at least 80 atomic percent silicon, or even at least 90 atomic percent silicon. The lithium storage layer segments are porous and preferably comprise porous silicon (including micropores and / or nanopores).

[0019] Figure 1B Roughly corresponding to Figure 1A The dashed circle B. The lithium storage layer may further include a modification layer on its surface, which may also extend downwards / extend to any discontinuity if present. For example, modification layers 108-1 and 108-2 (which may be collectively referred to herein as modification layer 108) are shown disposed on lithium storage layer segments 107-1 and 107-2, both on the upper surface of the segments (parallel to the x-axis) and also along their edges corresponding to discontinuities 117 (parallel to the z-axis). Although shown as separated in this cross-sectional schematic, in some cases, modification layers 108-1 and 108-2 may be bridged and merged together. Although shown as substantially continuous, the modification layers may be discrete or discontinuous. Although shown as a single layer, the modification layer may comprise multiple layers with different chemical compositions or gradient structures, wherein the chemical composition varies as a function of depth.

[0020] The modified layer is capable of conducting lithium ions but has low conductivity. This property can reduce the decomposition of the SSE at or near the interface with the negative electrode during LIB cell operation and / or limit the thickness of the solid electrolyte interface (SEI) that can be established between the negative electrode and the SSE. In some examples, the lithium-ion conductivity of the modified layer 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.

[0021] Figure 1C This is a cross-sectional view of a LIB cell based on some examples. Cell 165 includes a negative electrode 100, a positive electrode 140, and a solid electrolyte (“SSE”) 130 disposed between the negative and positive electrodes. The negative electrode 100 can be as described regarding... Figure 1AAs described. The positive electrode 140 may include a positive electrode current collector 143 and a positive electrode active material layer 147 configured to contact the positive electrode current collector with the lithium storage layer 107. The solid electrolyte includes lithium ions and is described in more detail elsewhere herein. In some preferred embodiments, the SSE is a solid sulfide. Figure 1D Roughly corresponding to Figure 1C The dashed circle D is used to illustrate the interface between SSE 130 and the negative electrode 100, particularly the modified layers (108-1, 108-2) between the SSE and the lithium storage layers (segments 107-1, 107-2). In this embodiment, SSE 130 substantially does not extend into the discontinuity 117. The extent to which SSE extends into the discontinuity depends on many factors, including but not limited to the size of the discontinuity and the viscosity of the SSE at the time of application. In particular, many inorganic SSE materials (such as solid sulfides) may be difficult to extend into the discontinuity, especially discontinuities with narrow widths.

[0022] The materials, methods, and properties related to the modified layer are discussed elsewhere in this document; however, it should be noted that the methods used to manufacture them, for the lithium storage layer materials described below, may include addition, conversion, or subtraction steps, or even combinations thereof. Although the discussion below uses silicon as an example, the same concepts can be applied to other lithium storage materials such as germanium, tin, and / or indium. In some preferred embodiments, the lithium storage layer is substantially free of carbon-based binders, graphitic carbon, graphene, graphene oxide, reduced graphene oxide, carbon black, and conductive carbon.

[0023] Addition methods can deposit new materials onto silicon. These new materials can be modified layers or precursors thereof. Some non-limiting examples may include sputtering, evaporation deposition, CVD (which can be PECVD or iCVD), atomic layer deposition (ALD), spatial ALD (S-ALS), molecular layer deposition (MLD), ion beam deposition, spraying, dip coating, roll coating, doctor blade coating, inkjet printing, flexographic printing, gravure printing, or some other deposition methods.

[0024] The conversion method may involve a chemical reaction in which a portion of the silicon initially provided as part of the lithium storage layer becomes part of the modified layer. This may include a reaction that converts some of the silicon near the surface into silicon dioxide (other than natural oxides that can exist at room temperature by simple air oxidation), silicon nitride, silicon oxynitride, silicates, or other silicon-containing compounds. In this conversion method, the silicon is no longer in a zero-valent oxidation state. In some cases, some or all of the silicon may be in its (IV) oxidation state, but in others, some or all may be in an intermediate oxidation state. In some cases, the conversion method involves optionally treating the lithium storage layer with a reactive gas at a high temperature. Alternatively, the method may involve optionally contacting the lithium storage layer with a reactive liquid, solution, or mixture at a high temperature. In some cases, the method may involve contacting the lithium storage layer with a plasma processing gas or a processing plasma formed from a plasma processing gas. In some cases, the plasma processing gas may include hydrogen, nitrogen, oxygen, argon, fluorocarbons or other fluorine-containing molecules, halogen-containing molecules, boron-containing molecules, carbon-containing molecules, phosphorus-containing molecules, sulfur-containing molecules, or oxygen-containing molecules, or any combination thereof. Note that "processing plasma" is used to process lithium storage material after most or all of the lithium storage material has been formed. Therefore, the plasma processing gas typically does not include a significant amount of negative electrode active material precursor gas (e.g., silane). For example, if used entirely, the negative electrode active material precursor gas constitutes less than 10%, alternatively less than 5%, or even less than 1%, where % can refer to the molar percentage of all gases, or alternatively, the volumetric flow rate of the gas added to the plasma chamber in mL / min. There are no particular limitations on the type of plasma device used to generate the processing plasma, but the processing plasma is typically gaseous and formed by exposing the plasma processing gas to some type of energy capable of ionizing the plasma processing gas (e.g., electrical or electromagnetic). Depending on the specific system, the processing plasma can be at approximately atmospheric pressure (e.g., 80–120 kPa), depressurized (less than 80 kPa), or high pressure (greater than 120 kPa).

[0025] Subtractive etching methods involve removing some lithium storage layer material near the exposed surface, for example by plasma etching, ion milling, chemical etching, or some other etching method. When using plasma etching, in some cases, the plasma processing gas may include hydrogen, nitrogen, oxygen, argon, fluorocarbons or other fluorine-containing molecules, halogen-containing molecules, boron-containing molecules, carbon-containing molecules, phosphorus-containing molecules, sulfur-containing molecules, or oxygen-containing molecules, or any combination thereof. In some cases, the plasma processing gas may include tetrafluoromethane or some other fluorinated or perfluorinated carbonaceous materials, optionally combined with oxygen. In some cases, chemical etching may include a mixture of aqueous hydrogen fluoride and silver nitrate, or alternatively may include an alkaline solution (e.g., KOH), an organic etchant (e.g., choline), or hydrogen sulfide gas.

[0026] Depending on the treatment, the surface of the lithium storage layer may not necessarily form a discrete, continuous layer, but the surface properties of the lithium storage material can be modified. For example, surface roughness can be increased. Alternatively or otherwise, surface energy (hydrophobicity) can be increased or decreased. For example, the surface of the treated lithium storage material may include monolayer or sub-monolayer chemical functional groups. In some non-limiting examples, such functional groups may include hydroxyl (-OH) moieties, hydroperoxy moieties (-OOH), halogen moieties (e.g., -F, -Cl, -Br, or -I), carbon-containing moieties (e.g., alkyl, alkenyl, or carboxyl groups), nitrogen-containing moieties (e.g., amines, imines, amides, or azo groups), sulfur-containing moieties (e.g., sulfidyl, sulfides, disulfides, or sulfonates), phosphorus-containing moieties (e.g., phosphinyl, phosphonyl, or phosphate groups), boron-containing moieties (borono, borino, or borinate groups), or siloxane moieties. Such a treated lithium storage layer may be referred to as having a chemically modified surface. For convenience, chemically modified surfaces are included as a type of modified layer in this paper.

[0027] Depending on the process, the surface regions of the lithium storage material can also be reacted to form a modified layer. Alternatively or additionally, the modified layer can be formed on the etched lithium storage layer by conversion and / or addition methods. In some cases, subtractive methods can also increase the surface roughness of the lithium storage layer, which can increase the adhesion of the SSE, increase the effective surface area in contact with the SSE, provide additional internal porosity channels for further modification, or any combination thereof. Alternatively, the subtractive method can be planarization to produce a flatter silicon surface that can improve the stacking of the SSE.

[0028] In some cases, the modified layer can alter the surface properties of the lithium storage layer. For example, silicon is known to have various surface states in the semiconductor field. Without being bound by theory, the authors propose that surface states can influence the electrochemical reduction of lithium ions to lithium metal, the alloying rate of lithium metal to silicon, or lithium ion diffusion in the SEI or SSE adjacent to silicon, or combinations thereof.

[0029] In some instances, the modified layer reduces the overpotential for lithium-ion reduction and / or increases the alloying rate of lithium metal into silicon. In some instances, the modified layer can enhance lithium-ion conduction from the silicon storage layer (SSE) to silicon compared to a lithium storage layer without a modified layer. For example, "vertical" lithium-ion conductivity can be enhanced corresponding to lithium-ion diffusion in a generally normal direction to the silicon surface covered by the modified layer. Alternatively or in addition, "lateral" lithium-ion conductivity can be enhanced corresponding to lithium-ion diffusion in a direction generally parallel to the silicon surface covered by the modified layer. Enhanced lateral lithium-ion conductivity is particularly useful for facilitating lithium-ion diffusion into discontinuities, so that lithiation and delithiation of the negative electrode are not limited to its top surface (e.g., ...). Figure 1D (As shown). In some cases, enhanced lateral lithium-ion conductivity can increase the effective surface area of ​​silicon to allow for faster charging / discharging.

[0030] In some cases, the modified layer has a multilayer structure, in which the modified sublayer in contact with silicon reduces the overpotential of lithium-ion reduction and / or increases the alloying rate of lithium metal into silicon, while the modified sublayer adjacent to the SSE enhances lithium-ion conduction (vertically or laterally) from the SSE to silicon.

[0031] In some instances, the modified layer promotes the adhesion, coating, or lamination of the SSE to the negative electrode, which can lead to better battery performance or reduced manufacturing costs.

[0032] In some instances, the modified layer protects the silicon surface from direct contact with contaminants or degradation products from SSE, such as sulfides or free thiosulfates. In other cases, the modified layer is inherently sacrificial.

[0033] In some instances, forming a modification layer alters the surface state (interface state) at the silicon / modification layer interface. For example, fewer electron-deficient defects (e.g., from hydrogen atoms) may exist at or near the silicon surface. Similarly, more electron-rich defects (e.g., from oxygen, nitrogen) may exist. This can lead to faster or longer-distance lithium-ion diffusion.

[0034] In some cases, the modified layer may include oxides, nitrides, or oxides of silicon. In some instances, the modified layer may include metal oxides, metal nitrides, or metal oxides of nitrides, such as those containing aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel, or tin, or mixtures thereof. Metal oxides, metal nitrides, or metal oxides of nitrides may include other components such as phosphorus or silicon. In some cases, zinc oxide can remove sulfide ions that may be unintentionally released from the SSE, reducing undesirable interactions with silicon. In some instances, the modified layer may include an inorganic-organic hybrid structure with alternating sublayers of metal oxides and bridging organic materials, such as so-called "metalcone" materials (e.g., zinc-based organic-inorganic hybrid films, titanium-based organic-inorganic hybrid films, aluminum-based organic-inorganic hybrid films, or zirconium-based organic-inorganic hybrid films). The modified layer may include lithium phosphorus oxynitride (LIPON), lithium phosphate, lithium aluminum oxide, or Li. x Si y Lithium-containing materials such as Al2O3 (where x and y are not zero) are used. In some cases, the thickness of the modified layer can be as low as a single monolayer. In other cases, the thickness of the modified layer can be in the range of 0.2-0.3 nm, alternatively 0.3-0.5 nm, alternatively 0.5-1.0 nm, 1-2 nm, 2-5 nm, 5-10 nm, 10-20 nm, 20-50 nm, 50-100 nm, or any combination of these ranges, or even thicker than 100 nm in some cases. In some cases, a modification that is too thin, such as below about 0.2 or 0.3 nm, may not provide the desired benefits as described above. In some cases, a modified layer that is too thick, such as above 100 nm, can lead to undesirable problems, such as increased resistance or slower charge / discharge rates. The specific range depends in part on the desired performance characteristics of the modified layer and the LIB cell.

[0035] Figure 1E This is a top view of a non-limiting example of a segmented lithium storage layer 107' comprising multiple lithium storage segments 107-x', wherein the dark line 106 indicates the segment space. Other lithium-ion battery components are not shown for clarity. In some examples, the segment space may occupy 0.01-5% of the negative electrode surface area, and alternatively 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35%, or 35-40% of the surface area, or any combination of these ranges.

[0036] Figure 1E The diagram shows a typical random pattern for lithium storage sections. In some other embodiments (not shown), the pattern may be more uniform, have a geometric shape, or even be partially or entirely predetermined.

[0037] In some instances, for most of the lithium storage segment within at least one 1mm × 1mm area of ​​the negative electrode, the ratio of the average lateral width LW of the lithium storage layer segment to the average thickness T of the lithium storage layer segment, for example, the LW / T ratio, can be at least 0.3. In some instances, this LW / T ratio can be less than 50. In some instances, the LW / T ratio can be in the range of 0.3-0.4, alternatively 0.4-0.5, alternatively 0.5-0.75, alternatively 0.75-1.0, alternatively 1.0-1.5, alternatively 1.5-2, alternatively 2-3, alternatively 3-4, alternatively 4-5, alternatively 5-7, alternatively 7-10, alternatively 10-15, alternatively 15-20, alternatively 20-25, alternatively 25-30, alternatively 30-40, alternatively 40-50, or any combination of these ranges, or even higher than 50. In some cases, an LW / T ratio that is too low, such as less than 0.3, can result in lower physical durability of the lithium storage layer or potentially smaller lithium storage capacity. In some cases, an LW / T ratio that is too high, such as greater than 50, can cause the segments to be more easily crushed and separated from the current collector. The specific range depends in part on other aspects of the lithium storage layer and the expected performance characteristics of the LIB cell.

[0038] In some cases, the lithium storage layer segments may have a spacing S measured in a dimension parallel to the current collector, wherein the spacing S is in the range of 0.2-0.5 nm, 0.5-1.0 nm, 1-2 nm, 2-5 nm, 5-10 nm, 10-20 nm, 20-50 nm, 50-100 nm, 100-200 nm, 200-300 nm, 300-500 nm, 500-700 nm, 700-1 μm, 1-2 μm, 2-3 μm, 3-5 μm, 5-7 μm, 7-10 μm, 10-12 μm, 12-15 μm, 15-20 μm, or any combination of such ranges. S may optionally be measured at the midpoint of the average thickness T of the lithium storage layer, or alternatively at a position approximately T / 5 downwards from the lithium storage surface. S may optionally correspond to the average of at least two measurements, such as the spacing between at least three segments along a linear cross section. In some cases, for example, when measured at a 1 mm cross section distance at the negative electrode, the sum of the individual spacings S may account for 0.01-5% of the total cross section distance, or alternatively 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35%, or 35-40% of the cross section distance, or any combination of their ranges.

[0039] Furthermore, it should be understood that the negative and positive electrodes are typically coated with their respective battery active materials (e.g., a lithium storage layer for the negative electrode and a positive electrode active material for the positive electrode) on both sides of their respective current collectors. Although the accompanying drawings show a single-sided negative and positive electrode structure, similar teachings can be applied to negative and positive electrodes coated on both sides of their respective current collectors.

[0040] While modification layers have been discussed concerning the top surface of lithium storage layers and the sidewalls of lithium storage layer segments formed by discontinuities, the disclosed materials and methods can also be used to form modification layer-type materials (“internal modification layers”) within lithium storage layer segments. For example, porous lithium storage layers (e.g., silicon) can include sufficiently random narrow paths (nanopaths) to allow for internal modification of the silicon-containing “walls” or features defining the nanopaths and pores. This can create an interconnected internal 3D network for lithium-ion transport, allowing for improved performance by fully utilizing lateral lithium-ion conductivity to enhance lithium-ion diffusion into the silicon segment itself. In some cases, lithium-ion diffusion occurs through the interfacial state between silicon and a silicon oxide-based internal modification layer, such as SiO2. Alternatively, metal oxides or other modification layer materials described herein can be used as internal modification layers. Such internal modification layers can be set, for example, by treating the negative electrode with a gas, plasma, or liquid containing the desired internal modification layer material or precursor. In some cases, an ALD (Alternating Layer Deposition) can be used. In some cases, the internal modification layer may not extend completely through the silicon; for example, it may be more prevalent near the silicon surface and less so (or absent) near the current collector.

[0041] The total reflectance and diffuse reflectance properties of the negative electrode can be measured using well-known conventional methods. Total reflectance (Rt) is the sum of specular reflectance (Rs) and diffuse reflectance (Rd). Measuring reflectance at 550 nm provides a convenient metric. It has been found that, in some cases, negative electrodes falling within certain reflectance metrics offer surprisingly excellent compatibility in solid-state batteries. In some cases, the negative electrode can have a total reflectance in the range of 8% to 30% (alternatively, 9% to 22%) and a total reflectance to diffuse reflectance ratio of less than 1.05 (alternatively, below 1.03), where the total reflectance and diffuse reflectance are measured at 550 nm on the side of the negative electrode with the lithium storage layer. Without being bound by theory, a total reflectance of less than 8% may indicate the presence of undesirable nanostructures, which could lead to a negative electrode that is not resistant to handling during battery construction. A total reflectance greater than 30% indicates that the surface of the lithium storage layer is too smooth, or alternatively, has a non-ideal chemical composition or physical structure, leading to poor adhesion in the battery, especially those using solid-state electrolytes. A total reflectance to diffuse reflectance ratio of less than 1.05 indicates sufficient roughness at the surface of the lithium storage layer for good contact with the SSE. In some cases, the treatments and / or modification layers discussed herein can provide the aforementioned reflectance to the negative electrode. In some cases, silicon deposition conditions alone may be sufficient to produce a negative electrode with the aforementioned reflective properties without the need for post-treatment or modification layers.

[0042] negative electrode

[0043] current collector

[0044] In some instances, the current collector or conductive layer can be characterized by its tensile strength Rm or yield strength Re. In some cases, the tensile and yield strength properties of the current collector depend primarily on the conductive layer, which in some instances can be thicker than the optional surface layer. If the tensile strength is too high or too low, it can become difficult to handle in some manufacturing processes, such as roll-to-roll methods. During the electrochemical cycling of the negative electrode, if the tensile strength is too low, deformation of the negative electrode may occur; alternatively, if the tensile strength is too high, the adhesion of the lithium storage layer may be impaired.

[0045] Negative electrode deformation is not a problem for all products, and it sometimes only occurs with higher capacity lithium storage layer materials, such as those with higher loads. For such products, in some cases, the current collector or conductive layer may be characterized by its tensile strength R. mWithin the range of 100-150 MPa, alternatively 150-200 MPa, alternatively 200-250 MPa, alternatively 250-300 MPa, alternatively 300-350 MPa, alternatively 350-400 MPa, alternatively 400-500 MPa, alternatively 500-600 MPa, alternatively 600-700 MPa, alternatively 700-800 MPa, alternatively 800-900 MPa, alternatively 900-1000 MPa, alternatively 1000-1200 MPa, alternatively 1200-1500 MPa, or any combination of these ranges.

[0046] In some cases, significant negative electrode deformation should be avoided, but low battery capacity would be unacceptable. For example, in some situations, when the negative electrode comprises amorphous silicon of 7 μm or more and / or the electrochemical cycle capacity is 1.5 mAh / cm³. 2 When the above is true, the characteristic of tensile strength R can be selected. m A current collector or conductive layer with a tensile strength greater than 450 MPa, alternatively greater than 500 MPa, alternatively greater than 550 MPa, or alternatively greater than 600 MPa. In such embodiments, the tensile strength can be in the range of about 450-500 MPa, alternatively 500-550 MPa, alternatively 550-600 MPa, alternatively 600-650 MPa, alternatively 650-700 MPa, alternatively 700-750 MPa, alternatively 750-800 MPa, alternatively 800-850 MPa, alternatively 850-900 MPa, alternatively 900-950 MPa, alternatively 950-1000 MPa, alternatively 1000-1200 MPa, alternatively 1200-1500 MPa, or any combination of these ranges. In some instances, the current collector or conductive layer may have a tensile strength greater than 1500 MPa. In some instances, the current collector or conductive layer is in the form of a foil having a tensile strength greater than 600 MPa and an average thickness in the range of 4-8 μm, alternatively 8-10 μm, alternatively 10-14 μm, alternatively 14-18 μm, alternatively 18 μm-20 μm, alternatively 20 μm-25 μm, alternatively 25 μm-30 μm, alternatively 30 μm-40 μm, alternatively 40 μm-50 μm, or any combination thereof.

[0047] In some instances, the conductive layer may have at least 10 3 S / m, or alternatively at least 10 6 S / m, or alternatively at least 10 7The conductivity is measured in S / m, and may include inorganic or organic conductive materials or combinations thereof. For negative electrodes with low capacity and / or where there are no concerns about negative electrode deformation during use, a wide range of conductive materials can be used as the conductive layer.

[0048] In some instances, the conductive layer comprises metallic materials such as titanium (and its alloys), nickel (and its alloys), copper (and its alloys), or stainless steel. In some instances, even metals such as tin or aluminum, which typically react with or alloy with lithium, may be suitable if the surface layer is sufficiently protective. In some instances, the conductive layer may comprise a multilayer structure, such as comprising multiple metals. In some instances, the conductive layer may be a foil. In some instances, the conductive layer comprises conductive carbon, such as carbon black, carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, and graphite. In some instances, the conductive layer may be in the form of a foil, mesh, fiber, fabric, or sheet of conductive material. Herein, “mesh” includes any conductive structure having openings such as those found in interwoven wires, foam structures, or foils with arrays of pores. In some instances, the conductive layer may comprise multiple layers of different conductive materials. The conductive layer may be in the form of a layer deposited on an insulating substrate (e.g., a polymer sheet or ceramic substrate optionally coated on both sides with conductive materials including, but not limited to, nickel or copper). In some instances, the conductive layer comprises a mesh or sheet of conductive carbon, including but not limited to those formed from bundles of carbon nanotubes or nanofibers or carbon fibers or fabrics.

[0049] When a higher tensile strength is desired, for example, where R m For pressures greater than 450 MPa, or alternatively greater than 500 MPa, 550 MPa, or 600 MPa, the conductive layer may include nickel (and certain alloys), or certain copper alloys such as brass (primarily an alloy of copper and zinc), bronze (primarily an alloy of copper and tin), CuMgAgP (primarily an alloy of copper, magnesium, silver, and phosphorus), CuFe2P (primarily an alloy of copper, iron, and phosphorus), CuNi3Si (primarily an alloy of copper, nickel, and silicon), CuCrZr (primarily an alloy of copper, chromium, and zirconium), and CuCrSiTi (primarily an alloy of copper, chromium, silicon, and titanium). The nomenclature of the metal alloys is not the stoichiometric formula used in chemistry, but rather the nomenclature used by those skilled in the art of alloying. For example, CuNi3Si does not imply three nickel atoms and one silicon atom for every copper atom. In some instances, these nickel-based or copper-based conductive layers with higher tensile strength may comprise rolled nickel or copper alloy foils.

[0050] Alternatively, conductive carbon meshes or sheets, including but not limited to those formed from bundles of carbon nanotubes or nanofibers, can in some cases provide conductive layers with higher tensile strength. In some instances, a conductive metal interlayer may be interposed between the conductive carbon and the surface layer.

[0051] In some instances, any of the aforementioned conductive layers (low tensile strength or high tensile strength) may be used as the primary conductive layer, and further include a conductive intermediate layer, such as a metallic intermediate layer, disposed between the primary conductive layer and the surface layer. For example, the conductive layer may be similar to those described in PCT International Publication No. WO2022 / 005999, which is incorporated herein by reference in its entirety for all purposes.

[0052] The metal interlayer can be applied by, for example, sputtering, vapor deposition, electroplating, electroless plating, or any convenient method. The average thickness of the metal interlayer is typically less than 50% of the average thickness of the total conductive layer, such as the combined thickness of the main conductive layer and the metal interlayer. In some instances, the surface layer can form more uniformly on or adhere better to the metal interlayer than the main conductive layer.

[0053] General surface roughness

[0054] In some instances, the current collector may be characterized by having a surface roughness. In some instances, and for example, the top surface of the modified layer 108 of the lithium storage layer 107, may have a lower surface roughness than that of the current collector 101. In this document, the average roughness (R0) can be used. a RMS roughness (R) q ), maximum profile peak height roughness (R p ), average maximum height of the profile (R) z ) or peak density (P c Surface roughness comparison and measurement are performed. In some instances, the current collector may be characterized by simultaneously having R... z Surface roughness ≥2.5μm and R a Surface roughness ≥0.25μm. In some instances, R... z Within the ranges of 2.5–3.0 μm, alternatively 3.0–3.5 μm, alternatively 3.5–4.0 μm, alternatively 4.0–4.5 μm, alternatively 4.5–5.0 μm, alternatively 5.0–5.5 μm, alternatively 5.5–6.0 μm, alternatively 6.0–6.5 μm, alternatively 6.5–7.0 μm, alternatively 7.0–8.0 μm, alternatively 8.0–9.0 μm, alternatively 9.0–10 μm, 10–12 μm, 12–14 μm, or any combination of these ranges. In some instances, Ra The range is 0.25-0.30 μm, alternatively 0.30-0.35 μm, alternatively 0.35-0.40 μm, alternatively 0.40-0.45 μm, alternatively 0.45-0.50 μm, alternatively 0.50-0.55 μm, alternatively 0.55-0.60 μm, alternatively 0.60-0.65 μm, alternatively 0.65-0.70 μm, alternatively 0.70-0.80 μm, alternatively 0.80-0.90 μm, alternatively 0.90-1.0 μm, alternatively 1.0-1.2 μm, alternatively 1.2-1.4 μm, or any combination of these ranges.

[0055] In some instances, some or most of the surface roughness of the current collector can be imparted by a conductive layer and / or a metallic interlayer. Alternatively, some or most of the surface roughness of the current collector can be imparted by a surface layer. Alternatively, some combinations of conductive layers, metallic interlayers, and surface layers can significantly contribute to the surface roughness.

[0056] In some instances, the conductive layer may include roughening features, such as electrodeposited roughening features, to increase surface roughness. In some instances, the electrodeposited roughening features may include copper features. In some cases, the current collector roughening features may take the form of nodules, hemispheres, nanopillars, or dendrites. In some cases, the roughening features may be characterized by a height H extending from the conductive layer and a maximum width. In some instances, the roughening features may be characterized by a height H ranging from about 0.1 μm to 0.2 μm, alternatively from 0.2 μm to 0.4 μm, alternatively from 0.4 μm to 0.6 μm, alternatively from 0.6 μm to 0.8 μm, alternatively from 0.8 μm to 1.0 μm, 1.0 μm to 1.5 μm, alternatively from 1.5 μm to 2 μm, alternatively from 2 μm to 3 μm, alternatively from 3 μm to 4 μm, alternatively from 4 μm to 5 μm, or any combination of these ranges. In some instances, the roughening feature may be characterized by a maximum width W ranging from approximately 0.1 μm to 0.2 μm, alternatively from 0.2 μm to 0.4 μm, alternatively from 0.4 μm to 0.6 μm, alternatively from 0.6 μm to 0.8 μm, alternatively from 0.8 μm to 1.0 μm, 1.0 μm to 1.5 μm, alternatively from 1.5 μm to 2 μm, alternatively from 2 μm to 3 μm, or any combination of these ranges. In some cases, the roughening feature may be characterized by an aspect ratio H / W ranging from approximately 0.8 to 1.0, alternatively from 1.0 to 1.5, alternatively from 1.5 to 2.0, alternatively from 2.0 to 2.5, alternatively from 2.5 to 3, alternatively from 3 to 4, alternatively from 4 to 5, alternatively from 5 to 6, alternatively from 6 to 8, alternatively from 6 to 10, or any combination of these ranges. In some instances, the average 10 μm × 10 μm surface of the conductive layer may include at least 3 roughening features, alternatively at least 4, alternatively at least 5, alternatively at least 6, alternatively at least 7, alternatively at least 8, alternatively at least 9, or alternatively at least 10.

[0057] Alternatively, or in combination with roughening features, the conductive layer may undergo other electrochemical, chemical, or physical treatments prior to the formation of the surface layer to impart the desired surface roughness.

[0058] In some instances, roughening of the conductive layer can include, for example, physical abrasion (such as sandpaper, sandblasting, or grinding), ablation (such as laser ablation), embossing, stamping, casting, imprinting, chemical treatment, electrochemical treatment, or thermal treatment. In some cases, this roughening can be used to form more than one of the above-mentioned roughening features, such as nodular features, nanopillar features, wide roughness features, or pit features. In some cases, the roughening features can be random, or alternatively, patterned.

[0059] Surface layer

[0060] In some instances, the surface layer can provide a chemical composition that promotes the formation of adhesive lithium storage layers, such as those deposited via CVD or PVD methods, particularly at the load or thickness of commercially useful lithium storage layers. In some cases, deposition solely onto the conductive layer may not be sufficient to provide uniform initial adhesion, making the lithium storage layer material easily brushed off or peeled off. Even when satisfactory initial adhesion exists, it may be insufficient during electrochemical formation and cycling. Some non-limiting examples of surface layers are discussed below. In some cases, the surface layer may comprise two or more distinct surface sublayers with different chemical compositions. In some cases, the surface layer, or even the surface sublayers, may comprise a mixture of different surface layer materials.

[0061] In some instances, the surface layer can be as thin as a single layer. In some instances, the thickness of the surface layer is in the range of 0.0002 μm to 0.0005 μm, alternatively 0.0005 μm to 0.001 μm, alternatively 0.001 μm to 0.005 μm, alternatively 0.002 μm to 0.005 μm, alternatively 0.005 μm to 0.01 μm, alternatively 0.01 μm to 0.02 μm, alternatively 0.02 μm to 0.03 μm, alternatively 0.03 μm to 0.05 μm, alternatively 0.05 μm to 0.1 μm, alternatively 0.1 μm to 0.2 μm, alternatively 0.2 μm to 0.5 μm, alternatively 0.5 μm to 1 μm, alternatively 1 μm to 2 μm, alternatively 2 μm to 5 μm, or any combination of these ranges.

[0062] In some instances, the surface layer or sublayer may include a metal-oxygen compound. In some cases, the metal-oxygen compound may include a metal oxide or metal hydroxide, such as a transition metal oxide or transition metal hydroxide. In some cases, the metal-oxygen compound may include a metal oxoate, such as a transition metal oxoate. In some instances, the surface layer may include a silicon compound comprising or derived from siloxanes, silanes (e.g., silane-containing compounds), silazanes, or their reaction products. In this document, "silicon compound" does not include simple elemental silicon, such as amorphous silicon. These materials are described in more detail below. In some instances, the surface layer may include a silicate compound. In some instances, the surface layer may include a metal silicide, such as a transition metal silicide. In some instances, the surface layer may include a metal chalcogenide, such as a metal sulfide, for example, a transition metal sulfide.

[0063] Lithium storage layer / lithium storage layer section

[0064] The following discussion can be applied to segmented or unsegmented lithium storage layers (or both). For convenience, in this section, any embodiment will be simply referred to as a lithium storage layer. In some instances, the lithium storage layer can be a porous material capable of reversibly binding lithium, such as a continuous porous lithium storage layer. In some instances, the lithium storage layer comprises silicon, germanium, antimony, tin, or a mixture of two or more of these elements. In some instances, the lithium storage layer is substantially amorphous. In some instances, the lithium storage layer comprises substantially amorphous silicon. Such substantially amorphous storage layers may include a small amount (e.g., less than 20 atoms) of crystalline material dispersed therein. The lithium storage layer may include dopants such as hydrogen, boron, phosphorus, sulfur, fluorine, aluminum, gallium, indium, arsenic, antimony, yttrium, scandium, bismuth, nitrogen, or metallic elements or any combination thereof. In some cases, the lithium storage layer includes doping with B (e.g., where the B doping may optionally be 10). 15 -10 22 cm -3 The lithium storage layer may contain silicon of the range of Al, Ga, In, Sc, or Y, or any combination thereof. Unbound by theory, this doping can lower the energy barrier associated with electron transport and lithiation. In some instances, the lithium storage layer may comprise porous, substantially amorphous hydride silicon (a-Si:H) with a hydrogen content of, for example, from 0.1 to 20 atomic percent or alternatively, higher. In some instances, the lithium storage layer may comprise methylated amorphous silicon. Note that unless specifically mentioned, any atomic percent metric used herein for lithium storage materials or layers refers to atoms other than hydrogen.

[0065] In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may comprise at least 40 atomic% silicon, germanium, or combinations thereof, alternatively at least 50 atomic%, alternatively at least 60 atomic%, alternatively at least 70 atomic%, alternatively at least 80 atomic%, or alternatively at least 90 atomic%. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may comprise 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%, alternatively at least 98%, or alternatively at least 99%. Note that in the case of the pre-lithiated anode discussed below, the lithium content is excluded from this atomic% characterization.

[0066] In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, is substantially free of (e.g., the lithium storage layer comprises less than 1 wt%, alternatively less than 0.5 wt%, alternatively less than 0.3 wt%, alternatively less than 0.1 wt%, alternatively less than 0.01 wt%) carbon-based binders, graphitic carbon, graphene, graphene oxide, reduced graphene oxide, carbon black, and conductive carbon. Some non-limiting examples of carbon-based binders may include organic polymers such as those based on styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, carboxymethyl cellulose, or polyacrylonitrile.

[0067] Lithium storage layers, such as continuous porous lithium storage layers, can include voids or gaps (pores) that can be random or non-uniform in size, shape, and distribution. These pores can sometimes co-form random nanopaths within the lithium storage layer that can extend to the surface. In some cases, this porosity can be tuned (e.g., by adjusting deposition conditions) to produce an appropriate surface area for the reaction to form an interfacial state or “internal” modified layer (similar to modified layers discussed elsewhere), which rapidly transports lithium ions into the bulk of the porous lithium storage layer. In some instances, the effective surface area or specific surface area of ​​the lithium storage layer (e.g., as measured by BET) can be 2–10 m². 2 / g, alternatives 6-10m 2 / g, 10-20m can be replaced 2 / g, 20-50m can be replaced 2 / g, 50-100m can be replaced 2The porosity is typically between 1.0 and 1.1 g / cm³. This porosity generally does not lead to the formation of any identifiable high-aspect-ratio lithium storage nanostructures such as nanowires or nanopillars, or such porosity is not generated by the formation of any identifiable high-aspect-ratio lithium storage nanostructures such as nanowires or nanopillars. In some instances, the pores can be polydisperse. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, can be characterized as nanoporous. In some instances, the average density of the lithium storage layer, such as a continuous porous lithium storage layer, is between 1.0 and 1.1 g / cm³. 3 Alternatives: 1.1-1.2 g / cm³ 3 Alternatives: 1.2-1.3 g / cm³ 3 Alternatives: 1.3-1.4 g / cm³ 3 Alternatives: 1.4-1.5 g / cm³ 3 Alternatives: 1.5-1.6 g / cm³ 3 Alternatives: 1.6-1.7 g / cm³ 3 Alternatives: 1.7-1.8 g / cm³ 3 Alternatives: 1.8-1.9 g / cm³ 3 Alternatives: 1.9-2.0 g / cm³ 3 Alternatives: 2.0-2.1 g / cm³ 3 Alternatives: 2.1-2.2 g / cm³ 3 Alternatives: 2.2-2.25 g / cm³ 3 Alternatives: 2.25-2.29 g / cm³ 3 Within the range of, or any combination thereof, and including at least 70 atomic% silicon, 80 atomic% silicon, alternatively at least 85 atomic% silicon, alternatively at least 90 atomic% silicon, alternatively at least 95 atomic% silicon, alternatively at least 97 atomic% silicon, alternatively at least 98 atomic% silicon, alternatively at least 99 atomic% silicon. Note that less than 2.3 g / cm³ 3 The density is evidence of the porous nature of the a-Si lithium storage layer.

[0068] In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, exhibits significant lateral connectivity of most of its active material (e.g., silicon, germanium, or alloys thereof) across portions of the current collector, resulting in this connectivity extending around random pores and gaps. In some instances, the porous lithium storage layer can be described as an interconnected matrix of silicon, germanium, or alloys thereof, with embedded random pores and gaps. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may have a sponge-like form in cross-sectional views. It should be noted that the lithium storage layer, such as a continuous porous lithium storage layer, does not necessarily extend through the entire negative electrode without any lateral breaks and may include random discontinuities or cracks, yet still be considered continuous. In some instances, such discontinuities may appear more frequently on rough current collector surfaces. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may have adjacent pillars of active material such as silicon in cross-sectional views. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may comprise a matrix of interconnected nanoparticle aggregates. In some instances, the lithium storage layer may comprise a mixture of amorphous and crystalline silicon, such as nanocrystalline silicon with an average grain size of less than about 100 nm, or alternatively less than about 50 nm, 20 nm, 10 nm, or 5 nm. In some cases, the lithium storage layer may comprise up to 30 atomic percent nanocrystalline silicon relative to all silicon in the lithium storage layer.

[0069] In some instances, lithium storage layers, such as continuous porous lithium storage layers, comprise substoichiometric oxides including silicon (SiO2). x ), germanium (GeO) x ) or tin (SnO) x The ratio of oxygen atoms to silicon, germanium, or tin atoms is less than 2:1, for example, x < 2, or alternatively less than 1:1, for example, x < 1. In some instances, x is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, or alternatively 0.50 to 0.95, alternatively 0.95 to 1.25, alternatively 1.25 to 1.50, or any combination of these ranges.

[0070] In some instances, lithium storage layers, such as continuous porous lithium storage layers, comprise substoichiometric nitrides including silicon (SiN). y ), germanium (GeN) y ) or tin (SnN) yThe ratio of nitrogen atoms to silicon, germanium, or tin atoms is less than 1.25:1, for example, y < 1.25. In some instances, y is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, or alternatively 0.50 to 0.95, alternatively 0.95 to 1.20, or any combination of these ranges. Lithium storage layers with substoichiometric silicon nitrides can also be referred to as nitrogen-doped silicon or silicon-nitrogen alloys.

[0071] In some instances, lithium storage layers, such as continuous porous lithium storage layers, comprise the following substoichiometric nitrides: silicon (SiO2). x N y ), germanium (GeO) x N y ) or tin (SnO) x N y (x+y) is a compound in which the ratio of total oxygen and nitrogen atoms to silicon, germanium, or tin atoms is less than 1:1, for example, (x+y)<1. In some instances, (x+y) is in the range of 0.02 to 0.95, alternatively 0.02 to 0.10, alternatively 0.10 to 0.50, or alternatively 0.50 to 0.95, or any combination of these ranges.

[0072] In some instances, the aforementioned substoichiometric oxides, substoichiometric nitrides, or substoichiometric nitrogen oxides are set using CVD methods, including but not limited to PECVD. Oxygen and nitrogen can be uniformly disposed within a continuous porous lithium storage layer, or alternatively, the oxygen or nitrogen content can vary as a function of the storage layer thickness.

[0073] CVD

[0074] CVD typically involves the influx of a precursor gas, a vaporized liquid (in the case of direct liquid injection CVD), or a gas and liquid mixture into a chamber containing one or more typically heated objects to be coated. Chemical reactions can occur on and near the hot surface, resulting in the deposition of a thin film on the surface. This is accompanied by the generation of chemical byproducts that exit the chamber along with unreacted precursor gases. As anticipated for the wide variety of deposited materials and broad range of applications, numerous variations of CVD exist that can be used to form lithium storage layers, surface or sublayers, supplementary layers (see below), or other layers. In some instances, it can be performed in hot-wall or cold-wall reactors, at total pressures from Yato to above atmospheric pressure, with or without a carrier gas, typically at temperatures ranging from 100–1600 °C. Several enhanced CVD methods also exist, involving the use of plasma, ions, photons, lasers, hot filaments, or combustion reactions to increase deposition rates and / or decrease deposition temperatures. Deposition can be controlled using various process conditions, including but not limited to temperature, precursor materials, gas flow rate, pressure, substrate bias (if applicable), and plasma energy (if applicable).

[0075] As described above, lithium storage layers, such as continuous porous lithium storage layers, such as silicon or germanium layers or both, can be formed by plasma-enhanced chemical vapor deposition (PECVD). Compared to conventional CVD, deposition via PECVD can typically be performed at lower temperatures and higher rates, which is advantageous for higher manufacturing yields. In some instances, PECVD is used to deposit substantially amorphous silicon layers (optionally doped) on surface layers. In some instances, PECVD is used to deposit substantially amorphous continuous porous silicon layers on surface layers.

[0076] In PECVD methods, depending on the implementation, plasma can be generated in a chamber containing a substrate, or plasma can be generated upstream of the chamber and fed into it. 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, combined PECVD, and microwave sources. In some instances, magnetron-assisted RF PECVD can be used.

[0077] PECVD process conditions (temperature, pressure, precursor gas, carrier gas, dopant gas, flow rate, and energy, etc.) can vary depending on the specific methods and tools used, as is known in the art.

[0078] In some embodiments, the PECVD method is an expanding thermal plasma chemical vapor deposition (ETP-PECVD) method. In such a method, a plasma-generating gas is passed through a DC arc plasma generator to form a plasma, which includes a current collector mesh or other substrate optionally in an adjacent vacuum chamber. A silicon source gas is injected into the plasma, generating free radicals. The plasma expands through an expanding nozzle and is injected into the vacuum chamber and directed to the substrate. An example of a plasma-generating gas is argon (Ar). In some instances, ionized argon in the plasma collides with silicon source molecules to form silicon source free radicals, resulting in deposition onto the current collector. Examples of DC plasma source voltage and current range from 60 to 80 volts and 40 to 70 amperes, respectively.

[0079] Silicon can be deposited using any suitable silicon source. In some instances, the silicon source can be a silane precursor gas, including but not limited to silane (SiH4), dichlorosilane (H2SiCl2), monochlorosilane (H3SiCl), trichlorosilane (HSiCl3), silicon tetrachloride (SiCl4), disilane, tetrafluorosilane, triethylsilane, and diethylsilane. Depending on the gas used, the silicon layer can be formed by decomposition or reaction with other compounds, such as by hydrogen reduction. In some instances, the gas can include a silicon source such as silane, a rare gas such as helium, argon, neon, or xenon, optionally one or more dopant gases, and substantially no hydrogen. In some instances, the gas can include argon, silane, and hydrogen, and optionally some dopant gases. In some instances, the gas flow rate ratio of argon to the combined gas flow rate of silane and hydrogen is at least 3.0, and alternatively at least 4.0. In some instances, the gas flow rate ratio of argon to the combined gas flow rate of silane and hydrogen is in the range of 3-5, alternatively 5-10, alternatively 10-15, alternatively 15-20, or any combination thereof. In some instances, the gas flow rate ratio of hydrogen to silane is in the range of 0-0.1, alternatively 0.1-0.2, alternatively 0.2-0.5, alternatively 0.5-1, alternatively 1-2, alternatively 2-5, or any combination thereof. In some instances, increasing the gas flow rate ratio of silane to the combined gas flow rate of silane and hydrogen can result in silicon with higher porosity and / or can increase the rate of silicon deposition. In some instances, the dopant gas is borane or phosphine, which may optionally be mixed with the carrier gas. In some instances, the gas flow rate ratio of dopant gas (e.g., borane or phosphine) to silicon source gas (e.g., silane) is in the range of 0.0001–0.0002, alternatively 0.0002–0.0005, alternatively 0.0005–0.001, alternatively 0.001–0.002, alternatively 0.002–0.005, alternatively 0.005–0.01, alternatively 0.01–0.02, alternatively 0.02–0.05, alternatively 0.05–0.10, or any combination of these ranges. Such gas flow rate ratios can refer to relative gas flow rates, such as standard cubic centimeters per minute (SCCM). In some instances, PECVD deposition conditions and gases can be changed during the deposition process.

[0080] In some instances, during at least a portion of the PECVD deposition process, the temperature at the current collector is within the ranges of 20°C to 50°C, 50°C to 100°C, alternatively 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 these ranges. In some instances, the temperature may vary during the PECVD deposition process. For example, the temperature during the earlier stages of the PECVD process may be higher than the temperature during later stages. Alternatively, the temperature during the later stages of the PECVD process may be higher than the temperature during the earlier stages.

[0081] The thickness or mass per unit area of ​​a lithium storage layer, such as a continuous porous lithium storage layer, depends on the storage material, the desired charge capacity, and other operational and lifetime considerations. Increasing thickness generally provides greater capacity. If the lithium storage layer becomes too thick, resistance increases and stability decreases. In some instances, the negative electrode may be characterized by an active silicon areal density of at least 0.2 mg / cm². 2 Alternatively, at least 0.5 mg / cm³ 2 Alternatively, at least 1.0 mg / cm³ 2 Alternatively, at least 1.5 mg / cm³ 2 Alternatively, at least 3 mg / cm³ 2 Alternatively, at least 5 mg / cm³ 2 In some instances, lithium storage structures are characterized by an active silicon areal density of 0.2-0.5 mg / cm³. 2 Within the range, alternatively at 0.5-1.0 mg / cm³. 2 Within the range, alternatively at 1.0-1.5 mg / cm³. 2 Within the range, alternatively at 1.5-2 mg / cm³ 2 Within the range, alternatively at 2-3 mg / cm 2 Within the range, alternatively at 3-5 mg / cm 2 Within the range, alternatively at 5-10 mg / cm³ 2 Within the range, alternatively at 10-15 mg / cm³ 2 Within the range, alternatively at 15-20 mg / cm³ 2 "Active silicon" refers to silicon that is electrically connected to the current collector and is available for reversible lithium storage at the start of a battery cycle, such as after the formation of the negative electrode electrochemistry. "Area density" refers to the surface area of ​​the conductive layer on which the active silicon is disposed. In some instances, not all silicon content is active silicon; for example, some may be bound in the form of inactive silicides or may be electrically isolated from the current collector.

[0082] In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, has an average thickness of at least 0.5 μm, alternatively at least 1 μm, alternatively at least 2.5 μm, alternatively at least 5 μm, or alternatively at least 6.5 μm. In some instances, the average thickness of the lithium storage layer, such as a continuous porous lithium storage layer, ranges from about 0.5 μm to about 50 μm. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, comprises at least 80 atomic percent amorphous silicon and / or has a thickness in the following ranges: 1-1.5 μm, alternatively 1.5-2.0 μm, alternatively 2.0-2.5 μm, alternatively 2.5-3.0 μm, alternatively 3.0-3.5 μm, alternatively 3.5-4.0 μm, alternatively 4.0-4.5 μm, alternatively 4.5-5.0 μm, or alternatively 5.0-5.5 μm. Alternatives are available in 5.5-6.0 μm, 6.0-6.5 μm, 6.5-7.0 μm, 7.0-8.0 μm, 8.0-9.0 μm, 9.0-10 μm, 10-15 μm, 15-20 μm, 20-25 μm, 25-30 μm, 30-40 μm, 40-50 μm, or any combination of these ranges.

[0083] In some instances, lithium storage materials can be formed using physical vapor deposition (PVD) methods, such as sputtering, instead of CVD or PECVD. Although the deposition rate of sputtering is generally lower than that of PECVD, sputtering can be suitable for applications requiring relatively low loading of active materials such as silicon. For example, in some instances, the thickness of lithium storage layers formed by sputtering methods, such as continuous porous lithium storage layers, can be less than about 15 μm, alternatively less than about 10 μm, alternatively less than 7 μm, alternatively less than 5 μm, or alternatively less than 3 μm.

[0084] Other negative electrode characteristics

[0085] The negative electrode may optionally include various additional layers and features. The current collector may include more than one feature to ensure a reliable electrical connection in the energy storage device.

[0086] In some instances, the lithium storage layer may be at least partially pre-lithiated before the first electrochemical cycle after battery assembly or alternatively before battery assembly. That is, some lithium may be incorporated into the lithium storage layer to form a lithiated storage layer even before the first battery cycle. Note that "lithiated storage layer" simply means that at least some of the potential storage capacity of the lithium storage layer is filled, but not necessarily all of it. In some instances, the lithiated storage layer may include lithium in the range of 1% to 5%, alternatively 5% to 10%, alternatively 10% to 15%, alternatively 15% 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 lithium storage layer, or any combination of these ranges.

[0087] In some instances, pre-lithiation may include, for example, depositing lithium metal on a lithium storage layer, such as a continuous porous lithium storage layer, or alternatively between one or more lithium storage sublayers, by evaporation, electron beam, or sputtering. Alternatively, pre-lithiation may include contacting the negative electrode with a reducing lithium organic compound, such as lithium naphthalene or lithium n-butyl. In some instances, pre-lithiation may include incorporating lithium by electrochemically reducing lithium ions in a pre-lithiation solution. In some instances, pre-lithiation may include thermal treatment to facilitate lithium diffusion into the lithium storage layer.

[0088] In some instances, the negative electrode can be heat-treated prior to battery assembly. In some instances, such as by inducing the migration of metals from the current collector or atoms from an optional supplementary layer into the lithium storage layer, heat-treated negative electrodes can improve the adhesion or conductivity of various layers.

[0089] In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, comprises at least 0.05 atomic% of one or more transition metals, alternatively at least 0.1 atomic%, alternatively at least 0.2 atomic%, alternatively at least 0.5 atomic%, or alternatively at least 1 atomic%. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, comprises less than about 10 atomic% of one or more transition metals, alternatively less than 5 atomic%, alternatively less than 2 atomic%, alternatively less than 1 atomic%, alternatively less than 0.5 atomic%, or alternatively less than 3 atomic%. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may comprise one or more transition metals within the following atomic percentage ranges: 0.05-0.1%, alternatively 0.1-0.2%, alternatively 0.2-0.5%, alternatively 0.5-1%, alternatively 1-2%, alternatively 2-3%, alternatively 3-5%, alternatively 5-7%, alternatively 7-10%, or any combination of these ranges. In some instances, the aforementioned atomic percentage range of the transition metal can correspond to at least 1 μm of lithium storage layer. 2 The cross-sectional area can be measured, for example, by energy-dispersive X-ray spectroscopy (EDS). In some instances, the aforementioned transition metal atomic percentage value may represent the atomic percentage of a single transition metal, or alternatively may correspond to a combined atomic percentage when a mixture of transition metals is present. Some non-limiting examples of transition metals that may be present in the lithium storage layer include copper, nickel, titanium, vanadium, and molybdenum. In some instances, the concentration of the transition metal present in the portion of the lithium storage layer near the current collector is higher than the gradient in the portion away from the current collector. In some instances, the lithium storage layer, such as a continuous porous lithium storage layer, may include the same transition metal found in the transition metal salts of the conductive layer or surface layer. In some cases, more than one transition metal can be provided in the lithium storage layer by heat treatment, thereby causing metal migration into the lithium storage layer; however, other methods, such as co-deposition of lithium storage materials and metals, can be used.

[0090] In some instances, the heat-treated negative electrode can be performed in a controlled environment with low levels of oxygen and water (e.g., less than 10 ppm or a partial pressure of less than 0.1 Torr, or alternatively less than 0.01 Torr to prevent degradation). In some instances, the negative electrode heat treatment can be performed using an oven, an infrared heating element, contact with a hot plate, or exposure to a flash lamp. The temperature and time of the negative electrode heat treatment depend on the material of the negative electrode. In some instances, the negative electrode heat treatment involves heating the negative electrode to a temperature range of at least 50°C, optionally from 50°C to 950°C, alternatively from 100°C to 250°C, alternatively from 250°C to 350°C, alternatively from 350°C to 450°C, alternatively from 450°C to 550°C, alternatively from 550°C to 650°C, alternatively from 650°C to 750°C, alternatively from 750°C to 850°C, alternatively from 850°C to 950°C, or a combination of these ranges. In some instances, heat treatment can be applied for periods ranging from 0.1 to 120 minutes.

[0091] In some instances, a roll-to-roll method can be used to perform one or more of the above processing steps, wherein the conductive layer or current collector is in the form of a rolled film, such as a roll of metal foil, mesh, or fabric.

[0092] SSE

[0093] In some cases, the SSE material can be applied to the negative electrode surface by, for example, extrusion, coating methods (e.g., gravure printing, slot die coating, spraying, dip coating, inkjet printing, flexographic printing, bar coating, or doctor blade coating), lamination of pre-formed SSE films, optionally placed on a donor sheet, or some other method. In some cases, a heating step (drying, annealing, or sintering, etc.) may be included after application. The negative electrode of the present invention, which is generally substantially binder-free in some preferred embodiments, is highly compatible with such application methods. Such negative electrodes can withstand a wide range of solvents and temperatures. In some cases, the SSE material can be applied to the positive electrode first and then contacted with the negative electrode during battery construction. Alternatively, the SSE can be a self-standing film laminated to both the negative and positive electrodes simultaneously during battery construction. Regardless of the method, in some cases, contacting the SSE with the negative electrode may optionally involve drying and / or anaerobic conditions.

[0094] Solid-state electrolytes (SSEs) comprise mobile lithium-ion sources that diffuse between the negative and positive electrodes (diffused to the negative electrode during charging and away from the negative electrode during discharging). The three main families of SSEs are solid polymer electrolytes (SPEs), solid inorganic electrolytes (SIEs), and hybrid SSEs using both SPE and SIE materials. In some cases, the lithium-ion source may comprise a lithium salt, which may be in the form of small molecules (e.g., LiTSFI, LiPF6, or any other lithium salt described below) suspended or dissolved in the SSE matrix. In some cases, the SPE material may comprise anionic functional groups that can act as counterions to the lithium salt. SSEs may optionally include plasticizers, rheology control agents, or even small amounts of organic solvents.

[0095] Non-limiting examples of polymeric materials that can be used in SSE compositions include poly(ethylene oxide) (PEO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(trimethylene carbonate), diester polymers, PVdF polymers, polycaprolactone, and their derivatives or copolymers, which can be used alone or in combination. In some cases, the polymer of the SSE can be crosslinked or branched. The polymer can be a block copolymer. The polymeric SSE can be completely amorphous or include some degree of crystallinity. The polymer can include anionic functional groups.

[0096] Some non-limiting classes of SIE materials that can be used in SSE compositions include b-alumina, LISICON, thio-LISICON, NASICON, perovskite, anti-perovskite, garnet, complex hydrides, and solid sulfides.

[0097] Some non-limiting categories of solid sulfides include ceramic sulfides, glassy sulfides, and glass-ceramic sulfides. Glassy sulfides exhibit minimal long-range order, which is identified by the lack of peaks in patterns produced by x-ray diffraction (XRD) measurements. Glass-ceramic sulfides comprise regions of glassy structure and regions of long-range order, which are identified by characteristic peaks in patterns produced by XRD measurements. Ceramic sulfides, also known as crystalline sulfides, consist of regions of long-range order, which are identified by characteristic peaks in patterns produced by XRD measurements. Non-limiting examples of ceramic sulfides include argillium sulfide, silicon thiophosphate, and silicon thiophosphate halide. Exemplary but non-limiting solid sulfides comprise thiophosphate (PS4), which can be identified by characteristic features in patterns produced by infrared or Raman spectroscopy. Some other examples of solid sulfides may include Li6PS5Cl, such as Li 10 GeP2S 12 LGPS materials and such as Li7P3S 11 LPS materials, etc.

[0098] In some instances, under battery operating conditions, the lithium-ion conductivity of the SSE can be in the range of 0.001 mS / cm to 0.01 mS / cm, alternatively in the range of 0.01 mS / cm to 0.1 mS / cm, alternatively in the range of 0.1 mS / cm to 1.0 mS / cm, and alternatively above 1 mS / cm.

[0099] In some instances, the solid electrolyte comprises a material that reversibly transitions from a low-fluidity state to a high-fluidity state and back to a low-fluidity state. In some cases, this cycle may be used only once, and such systems may be referred to as “single-cycle reversible.” For example, the SSE in a first low-fluidity state may have a first chemical composition or morphology. After a high-fluidity state transition, the SSE may revert to a second low-fluidity state and have a second chemical composition or morphology different from the first. For example, the SSE may undergo polymerization or crosslinking reactions during or after the high-fluidity state, thereby forming a second low-fluidity state that is no longer readily transitioning to a high-fluidity state. In some other embodiments, the cycle may be repeated more than twice (“multiple-cycle reversible”). In some cases, the low-fluidity state may correspond to a glassy state or a solid state. In some instances, the high-fluidity state may correspond to a liquid state. In some instances, the transition from a low-fluidity state to a high-fluidity state may correspond approximately to the melting point of the SSE material, or alternatively, to the glass transition temperature (Tg) of the SSE material. In some instances, the transition from a low-fluidity state to a high-fluidity state can be achieved by applying energy to the precursor cell, raising the temperature of the SSE within the precursor cell to T1, where the transition can occur. This energy can be applied, for example, by placing the precursor cell in an oven or on a hot plate, exposing it to a flash lamp, wrapping the cell in a heating coil, resistively heating the precursor cell components, microwave exposure, or other methods. T1 is typically above room temperature. In some instances, T1 can be at least 40°C, and alternatively at least 50°C, 60°C, 80°C, 100°C, 125°C, 150°C, 175°C, or 200°C. In some instances, T1 can be in the range of 40-60°C, or alternatively in the ranges of 60-80°C, 80-100°C, 100-125°C, 125-150°C, 150-175°C, 175-200°C, 200-225°C, 225-250°C, or any combination thereof. In some instances, compression can be applied to the precursor cell (between the negative and positive electrodes) while the SSE is in a highly fluid state. This compression can include a force greater than 1 bar, or alternatively greater than 1.5 bar, 2 bar, 3 bar, 4 bar, 5 bar, 7 bar, or 10 bar. In some cases, compression is performed within the range of 1.1-1.5 bar, 1.5-2 bar, 2-3 bar, 3-4 bar, 4-5 bar, 5-7 bar, 7-10 bar, 10-15 bar, 15-20 bar, 20-30 bar, 30-50 bar, 50-75 bar, 75-100 bar, or any combination thereof.

[0100] In some instances, a high-flowability state may be characterized by a viscosity of less than 1 MPa-sec, or alternatively less than 500 kPa-sec, 200 kPa-sec, 100 kPa-sec, 50 kPa-sec, 20 kPa-sec, 10 kPa-sec, 5 kPa-sec, 2 kPa-sec, 1 kPa-sec, 500 Pa-sec, 200 Pa-sec, 100 Pa-sec, 50 Pa-sec, 20 Pa-sec, 10 Pa-sec, 5 Pa-sec, 2 Pa-sec, 1 Pa-sec, 0.5 Pa-sec, 0.2 Pa-sec, or 0.1 Pa-sec. In some cases, a high-flowability state can be characterized by a viscosity in the range of 0.001-0.01 Pa-sec, or alternatively 0.01-0.1 Pa-sec, 0.1-1 Pa-sec, 1-10 Pa-sec, 10-100 Pa-sec, 100-1000 Pa-sec, 1-10 kPa-sec, 10-100 kPa-sec, 100-500 kPa-sec, or any combination of these ranges.

[0101] The low liquidity state has at least 1.1 times higher liquidity than the high liquidity state, and can be alternatively valued at least 1.5 times, 2 times, 5 times, 10 times, 20 times, 50 times, 100 times, 200 times, 500 times, 1000 times, and 10 times higher liquidity. 4 × or 10 5 × times the viscosity. In some instances, the low-flowability state may have a viscosity of at least 100 Pa-sec, alternatively at least 1 kPa-sec, alternatively at least 10 kPa-sec, alternatively at least 100 kPa-sec, or alternatively at least 1 MPa-sec.

[0102] The transition from a high-fluidity state to a low-fluidity state can include active cooling to T2 (or below), for example, using a cooler or heat pump, thereby removing heat from the battery. Alternatively, in cases where radiative cooling occurs, such as when the room temperature is equal to or below T2, passive cooling can be used. In some cases, T2 is less than T1; for example, T2 may be 1-5°C lower than T1, or alternatively, 5-10°C lower, 10-20°C lower, 20-30°C lower, 30-40°C lower, 40-50°C lower, 50-75°C lower, 75-100°C lower, 100-150°C lower, or any combination of these ranges, or even more than 150°C lower.

[0103] positive electrode

[0104] Positive electrode (positive electrode) active materials include, but are not limited to, 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 Z O2, LiFe2(SO4)3 or Li2FeSiO4), fluorinated carbon, metal fluorides such as iron fluoride (FeF3), metal oxides, sulfur, selenium, and combinations thereof. The positive electrode active material can be manipulated, for example, by intercalation, conversion, or combination. In some cases, the positive electrode active material can be mixed with and coated with more than one binder to form the positive electrode. In some cases, the positive electrode can include polymers, SIE, or mixed SSE materials, such as any materials described elsewhere, and it can be the same as or different from the material used in the SSE layer between the negative and positive electrodes. In some cases, the solid electrolyte used in the positive electrode can be different from the SSE layer; for example, it can have lower fluidity than the SSE layer. The positive electrode active material is typically disposed on or electrically connected to a conductive positive electrode current collector.

[0105] The positive electrode can optionally be larger in size relative to the negative electrode to provide additional lithium stock. This additional lithium stock can be electrochemically transferred to the negative electrode and retained therein during subsequent battery operation to increase the conductivity of the negative electrode.

[0106] Battery form

[0107] In some instances, the battery can be formed as a multi-layered stack of negative and positive electrodes, such as in pouch cells, button cells, or some prismatic cells. Alternatively, the negative / positive electrode stack can be formed as a so-called jelly-roll battery and used in cylindrical cells or some prismatic cells. This structure is set into a suitable housing with the desired electrical contacts. The battery may sometimes include a compression system that applies compressive force between the negative and positive electrodes. This can sometimes improve cycle life. This compression system may optionally apply a variable force. The compression system may, for example, include linear or non-linear springs (or some other components operating on a similar principle).

[0108] diaphragm

[0109] While not typically necessary when using a surface-sealable separator (SSE), the battery may optionally include a current separator between the negative and positive electrodes. The current separator allows lithium ions to flow between the negative and positive electrodes but prevents direct electrical contact, for example, when the SSE is in a high-flow state. Current separators are typically made in the form of porous sheets of electrically insulating materials. In some cases, the separator is a single-layer or multi-layer polymer sheet (e.g., based on polyolefins, PET, or PVDF). For example, the separator may alternatively include glass materials, ceramic materials, ceramic materials embedded in a polymer, ceramic-coated polymers, or some other composite or multilayer structures to provide greater mechanical and thermal stability. In some cases, the separator may have a porosity >30%, low ionic resistivity, a thickness of ~10 μm to 50 μm, and high bulk puncture strength.

[0110] lithium salts

[0111] As described above, some SSEs may include more than one lithium salt. SSEs may include more than one of the following non-limiting examples: LiPF6, LiBF4, LiClO4, LiAsF6, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiCF3SO3, LiC(CF3SO2)3, LiPF4(CF3)2, LiPF3(C2F5)3, LiPF3(CF3)3, LiPF3(iso-C3F7)3, LiPF5(iso-C3F7), and lithium salts having cyclic alkyl groups (e.g., (CF2)2(SO2)). 2x Li and (CF2)3(SO2) 2x Li), LiFSI (lithium bis(fluorosulfonyl)imide), LiTDI (lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium), and combinations thereof. In some instances, the effective concentration of lithium ions in the SSE may be at least 0.3 M, alternatively at least 0.7 M, alternatively at least 1 M, or alternatively at least 1.5 M.

[0112] In some instances, the SSE may include a relatively small amount of organic solvent, for example, to increase lithium-ion conductivity or simply as a carrier for adding lithium salts. In some instances, the solvent weight percentage relative to other components of the SSE may be less than 10%, alternatively less than 5%, 2%, 1%, 0.5%, 0.2%, or 0.1%. Some non-limiting examples of non-aqueous solvents suitable for some lithium-ion batteries, if used entirely, include the following: cyclic carbonates (e.g., ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), butyl carbonate (BC), and vinyl ethylene carbonate (VEC)), vinylene carbonate (VC); lactones (e.g., γ-butyrolactone (GBL), γ-valerolactone (GVL), and α-angelicrolactone (AGL)); linear carbonates (e.g., dimethyl carbonate (DMC), ethyl methyl carbonate (MEC, often also abbreviated as EMC), diethyl carbonate (DEC), methyl propyl carbonate (MPC)). Dipropyl carbonate (DPC), 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 neopentanoate, butyl neopentanoate, and octyl neopentanoate); amides (e.g., dimethylformamide); organophosphates (e.g., trimethyl phosphate and trioctyl phosphate); organic compounds containing an S=O group (e.g., dimethyl sulfone and divinyl sulfone) and combinations thereof.

[0113] In some instances, electrochemical cycling conditions can be set to utilize only a portion of the theoretical charge / discharge capacity of silicon (3600 mAh / g). In some instances, electrochemical charge / discharge cycles can be set to utilize 400-600 mAh / g, alternatively 600-800 mAh / g, alternatively 800-1000 mAh / g, alternatively 1000-1200 mAh / g, alternatively 1200-1400 mAh / g, alternatively 1400-1600 mAh / g, alternatively 1600-1800 mAh / g, alternatively 1800 mAh / g. -2000mAh / g, alternatively 2000-2200mAh / g, alternatively 2200-2400mAh / g, alternatively 2400-2600mAh / g, alternatively 2600-2800mAh / g, alternatively 2800-3000mAh / g, alternatively 3000-3200mAh / g, alternatively 3200-3400mAh / g, or any combination of their ranges.

[0114] List of implementation plans

[0115] Example 1. A lithium-ion battery cell comprising:

[0116] The negative electrode comprises a porous lithium storage layer disposed on a negative electrode current collector and a modification layer disposed on the lithium storage layer.

[0117] in:

[0118] i) The lithium storage layer contains at least 40 atomic percent silicon, tin, germanium, or a combination thereof;

[0119] ii) The lithium storage layer includes discontinuities defining multiple lithium storage layer segments, each having an upper surface and sidewalls; and

[0120] iii) The modified layer is disposed on the upper surface and at least partially along the sidewalls;

[0121] The positive electrode includes a layer of positive electrode active material in electrical contact with the positive electrode current collector; and

[0122] A lithium-ion solid electrolyte (SSE) is located between a lithium storage layer and a positive electrode active material layer.

[0123] Example 2. The unit according to example 1, wherein the modified layer enhances lithium-ion conduction between the SSE and the lithium storage layer segment.

[0124] Scheme 3. The unit according to any one of the foregoing listed embodiments, wherein the modified layer reduces the overpotential of lithium ion reduction, increases the alloying rate of lithium metal into silicon, or both.

[0125] Example 4. The unit according to any one of the foregoing examples, wherein the modified layer includes, optionally, an electron-rich domain of oxygen.

[0126] 5. The unit according to any one of the foregoing listed embodiments, wherein the lithium storage layer comprises at least 80 atomic% amorphous silicon.

[0127] 6. The unit according to any one of the foregoing listed embodiments, wherein the lithium storage layer is substantially free of carbon-based binders and conductive carbon.

[0128] 7. The unit according to any one of the foregoing listed embodiments, wherein the modified layer has a multilayer or gradient structure.

[0129] 8. The unit according to any one of the foregoing listed embodiments, wherein the modified layer comprises silicon oxide, silicon nitride, or silicon oxynitride.

[0130] 9. The unit according to any one of the foregoing listed embodiments, wherein the modified layer comprises silicate.

[0131] 10. The unit according to any one of the foregoing listed embodiments, wherein the modified layer comprises a metal oxide.

[0132] 11. The unit according to any one of the foregoing listed embodiments, wherein the modified layer comprises titanium oxide, aluminum oxide, zirconium oxide, zinc oxide or nickel oxide.

[0133] 12. The unit according to any one of the aforementioned embodiments, wherein the modified layer comprises a titanium-based organic-inorganic hybrid film, an aluminum-based organic-inorganic hybrid film, a zirconium-based organic-inorganic hybrid film, or a zinc-based organic-inorganic hybrid film.

[0134] Scheme 13. The unit according to any one of the foregoing listed schemes, wherein the modified layer comprises lithium phosphate, lithium aluminum oxide, Li x Si y Al2O3 or lithium phosphorus oxynitrate (LiPON).

[0135] Example 14. The unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a solid polymer electrolyte.

[0136] 15. A unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a solid inorganic electrolyte.

[0137] Scheme 16. A unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a solid sulfide electrolyte.

[0138] Scheme 17. The unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a sulfur-silver-germanium-lithium solid electrolyte.

[0139] 18. A unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a lithium silicon sulfide solid electrolyte.

[0140] 19. A unit according to any one of the foregoing listed embodiments, wherein the SSE comprises a lithium silicon sulfide solid electrolyte.

[0141] 20. The unit according to any one of the foregoing listed embodiments, wherein the modified layer is formed at least in part by an addition method.

[0142] 21. The unit according to any one of the aforementioned listed embodiments, wherein the modified layer is formed at least in part by a conversion method.

[0143] 22. The unit according to any one of the foregoing listed embodiments, wherein the modified layer is formed at least in part by a subtractive method.

[0144] 23. The unit according to any one of the listed embodiments 1-22 further includes a compression system that applies a compressive force between the negative and positive electrodes.

[0145] 24. The unit according to any one of the foregoing listed embodiments, wherein the lithium storage layer comprises a substoichiometric silicon nitride.

[0146] Example 25. The unit according to example 24, wherein the ratio of nitrogen to silicon is in the range of 0.02 to 0.5, optionally in the range of 0.1 to 0.5.

[0147] Example 26. The unit according to any one of the foregoing examples, wherein the modified layer is formed at least in part by exposing the lithium storage material to a processing plasma comprising a fluorinated or perfluorinated carbon material, or a material formed of a fluorinated or perfluorinated carbon material.

[0148] Example 27. The unit according to example 26, wherein the modified layer comprises a fluorinated compound.

[0149] Example 28. The unit according to any one of the foregoing examples, wherein the modified layer comprises a metal nitride or a metal nitride, optionally wherein the metal of the metal nitride or metal nitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel or tin or combinations thereof.

[0150] Example 29. The unit according to any one of the foregoing examples, wherein the surface of at least some of the internal pores of the lithium storage layer includes an internal modification layer.

[0151] Example 30. The unit according to example 29, wherein the internal modification layer comprises a metal oxide or silicon oxide.

[0152] 31. The unit according to any one of the foregoing listed embodiments, wherein the positive electrode comprises a lithium metal oxide, wherein the metal comprises cobalt, nickel, manganese or any combination thereof.

[0153] Example 32. A negative electrode for a lithium-ion battery, the negative electrode comprising a porous lithium storage layer disposed on a negative electrode current collector, wherein:

[0154] i) The lithium storage layer contains at least 40 atomic percent silicon, tin, germanium, or a combination thereof;

[0155] ii) The lithium storage layer includes discontinuities defining multiple lithium storage layer segments, each having an upper surface and sidewalls; and

[0156] iii) The negative electrode has a total reflectance in the range of 8% to 30% and a total reflectance to diffuse reflectance ratio of less than 1.05, wherein the total reflectance and diffuse reflectance are measured at 550 nm on the side of the negative electrode with the lithium storage layer.

[0157] Example 33. The negative electrode according to example 32, wherein the total reflectivity is in the range of 9% to 22%, and the ratio of total reflectivity to diffuse reflectivity is less than 1.03.

[0158] Scheme 34. The negative electrode according to any one of the listed embodiments 32-33, wherein the lithium storage layer comprises a substoichiometric silicon nitride.

[0159] Example 35. The negative electrode according to example 34, wherein the ratio of nitrogen to silicon is in the range of 0.02 to 0.5, optionally in the range of 0.1 to 0.5.

[0160] Scheme 36. The negative electrode according to any one of the listed embodiments 32-35, wherein the lithium storage layer comprises at least 80 atomic% amorphous silicon.

[0161] Scheme 37. The negative electrode according to any one of the listed embodiments 32-36, wherein the lithium storage layer is substantially free of carbon-based binder and conductive carbon.

[0162] Example 38. A negative electrode for a lithium-ion battery, the negative electrode comprising a porous lithium storage layer disposed on a negative electrode current collector, wherein:

[0163] i) The lithium storage layer contains at least 40 atomic percent silicon, tin, germanium, or a combination thereof;

[0164] ii) The lithium storage layer includes discontinuities defining multiple lithium storage layer segments, each having an upper surface and sidewalls; and

[0165] iii) A modified layer is disposed on the lithium storage layer, wherein the modified layer is disposed on the upper surface and at least partially along the sidewall.

[0166] Example 39. The negative electrode according to example 38, wherein the modified layer reduces the overpotential of lithium ion reduction, increases the alloying rate of lithium metal into silicon, or both.

[0167] Example 40. The negative electrode according to example 38 or 39, wherein the modified layer includes an electron-rich domain optionally containing oxygen.

[0168] Example 41. The negative electrode according to any one of examples 38-40, wherein the lithium storage layer comprises at least 80 atomic% amorphous silicon.

[0169] Scheme 42. The negative electrode according to any one of the listed embodiments 38-41, wherein the lithium storage layer is substantially free of carbon-based binder and conductive carbon.

[0170] Scheme 43. The negative electrode according to any one of the listed schemes 38-42, wherein the modified layer has a multilayer or gradient structure.

[0171] Scheme 44. The negative electrode according to any one of the listed embodiments 38-43, wherein the modified layer comprises silicon oxide, silicon nitride or silicon oxynitride.

[0172] 45. The negative electrode according to any one of the listed embodiments 38-44, wherein the modified layer comprises silicate.

[0173] Scheme 46. The negative electrode according to any one of the listed embodiments 38-45, wherein the modified layer comprises a metal oxide.

[0174] Scheme 47. The negative electrode according to any one of the listed schemes 38-46, wherein the modified layer comprises titanium oxide, aluminum oxide, zirconium oxide, zinc oxide or nickel oxide.

[0175] Example 48. The negative electrode according to any one of examples 38-47, wherein the modified layer comprises a metal nitride or a metal nitride, optionally wherein the metal of the metal nitride or metal nitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel or tin or combinations thereof.

[0176] Scheme 49. The negative electrode according to any one of the listed schemes 38-48, wherein the modified layer comprises a titanium-based organic-inorganic hybrid film, an aluminum-based organic-inorganic hybrid film, a zirconium-based organic-inorganic hybrid film, or a zinc-based organic-inorganic hybrid film.

[0177] Example 50. The negative electrode according to any one of examples 38-49, wherein the modified layer comprises lithium phosphate, lithium aluminum oxide, LixSiyAl2O3 or lithium phosphorus oxynitride (LiPON).

[0178] 51. The negative electrode according to any one of the listed embodiments 38-50, wherein the negative electrode has a total reflectance in the range of 8% to 30% and a total reflectance to diffuse reflectance ratio of less than 1.05, wherein the total reflectance and diffuse reflectance are measured at 550 nm on the side of the negative electrode having the lithium storage layer.

[0179] Example 52. The negative electrode according to example 51, wherein the total reflectivity is in the range of 9% to 22%, and the ratio of total reflectivity to diffuse reflectivity is less than 1.03.

[0180] Example 53. The negative electrode according to any one of examples 38-52, wherein the lithium storage layer comprises a substoichiometric silicon nitride.

[0181] Example 54. The negative electrode according to example 53, wherein the ratio of nitrogen to silicon is in the range of 0.02 to 0.5, optionally in the range of 0.1 to 0.5.

[0182] Example 55. The negative electrode according to any one of examples 38-54, wherein the modified layer is formed at least in part by exposing the lithium storage layer to a plasma processing gas or a processing plasma formed by the plasma processing gas, wherein the plasma processing gas includes hydrogen, nitrogen, fluorocarbons or other halogen-containing molecules, boron-containing molecules, carbon-containing molecules, phosphorus-containing molecules, sulfur-containing molecules or oxygen-containing molecules or any combination thereof.

[0183] Example 56. The negative electrode according to example 55, wherein the modified layer comprises a fluorine-containing compound.

[0184] Example 57. The negative electrode according to any one of the examples 38-56, wherein the modified layer includes one or more functional groups attached to the lithium storage layer at the upper surface and at least partially along the sidewalls, optionally wherein at least one functional group includes a hydroxyl moiety, a halogen moiety, a carbon-containing moiety, a nitrogen-containing moiety, a sulfur-containing moiety, a phosphorus-containing moiety, or a boron-containing moiety.

[0185] Example 58. The negative electrode according to any one of the examples 38-57, wherein the surface of at least some of the internal pores of the lithium storage layer includes an internal modification layer.

[0186] Example 59. The negative electrode according to example 58, wherein the internal modification layer comprises a metal oxide or silicon oxide.

[0187] Example 60. A lithium-ion battery cell comprising a negative electrode, a positive electrode, and an electrolyte disposed between the negative electrode and the positive electrode, according to any one of examples 32-59.

[0188] Example 61. The lithium-ion battery cell according to example 60, wherein the electrolyte comprises a liquid electrolyte.

[0189] Example 62. The lithium-ion battery cell according to example 60 or 61, wherein the electrolyte comprises a solid electrolyte.

[0190] Example 63. A method for manufacturing a negative electrode for a lithium-ion battery cell, the method comprising:

[0191] A silicon-containing porous lithium storage layer is deposited onto a current collector using PVD or CVD methods, wherein the lithium storage layer includes discontinuous portions defining multiple lithium storage layer segments, each having an upper surface and sidewalls; and

[0192] The upper surface and at least some of the sidewalls are treated to form a modified layer thereon.

[0193] Example 64. The method according to example 63, wherein the processing includes exposing the lithium storage layer to a plasma processing gas or a processing plasma formed by the plasma processing gas.

[0194] Example 65. The method according to example 64, wherein the plasma treatment gas includes hydrogen, nitrogen, fluorocarbons or other halogen-containing molecules, boron-containing molecules, carbon-containing molecules, phosphorus-containing molecules, sulfur-containing molecules or oxygen-containing molecules or any combination thereof.

[0195] Scheme 66. The method according to any one of the schemes 63-65, wherein the modified layer includes one or more functional groups attached to the lithium storage layer at the upper surface and at least partially along the sidewalls.

[0196] Example 67. The method according to example 66, wherein at least one functional group includes a hydroxyl moiety, a halogen moiety, a carbon-containing moiety, a nitrogen-containing moiety, a sulfur-containing moiety, a phosphorus-containing moiety, or a boron-containing moiety.

[0197] Scheme 68. The method according to any one of the listed schemes 63-67, wherein the modified layer is continuous over each lithium storage layer segment.

[0198] Scheme 69. The method according to any one of the schemes 63-68, wherein the modified layer has a multilayer or gradient structure.

[0199] 70. The method according to any one of the listed embodiments 63-69, wherein the modified layer comprises silicon oxide, silicon nitride, or silicon oxynitride.

[0200] 71. The method according to any one of the listed embodiments 63-70, wherein the modified layer comprises a silicate.

[0201] 72. The method according to any one of the listed embodiments 63-71, wherein the modified layer comprises a metal oxide.

[0202] Scheme 73. The method according to any one of the listed embodiments 63-72, wherein the modified layer comprises titanium oxide, aluminum oxide, zirconium oxide, zinc oxide or nickel oxide.

[0203] Example 74. The method according to any one of examples 63-73, wherein the modified layer comprises a metal nitride or a metal nitride, optionally wherein the metal of the metal nitride or metal nitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel or tin or combinations thereof.

[0204] 75. The method according to any one of the listed embodiments 63-74, wherein the modified layer comprises a titanium-based organic-inorganic hybrid film, an aluminum-based organic-inorganic hybrid film, a zirconium-based organic-inorganic hybrid film, or a zinc-based organic-inorganic hybrid film.

[0205] Scheme 76. The method according to any one of the listed embodiments 63-75, wherein the modified layer comprises lithium phosphate, lithium aluminum oxide, Li x Si y Al2O3 or lithium phosphorus oxynitrate (LiPON).

[0206] 77. The method according to any one of the listed embodiments 63-76, wherein the processing includes an additive method.

[0207] 78. The method according to any one of the listed embodiments 63-77, wherein the processing includes a transformation method.

[0208] 79. The method according to any one of the listed embodiments 63-78, including a reduction method.

[0209] 80. The method according to any one of the listed embodiments 63-79, wherein the deposition of the silicon-containing porous lithium storage layer includes PECVD.

[0210] Example 81. A method for manufacturing a negative electrode for a lithium-ion battery cell, the method comprising:

[0211] A silicon-containing porous lithium storage layer is deposited onto a current collector using PVD or CVD methods, wherein the lithium storage layer includes discontinuous portions defining multiple lithium storage layer segments, each having an upper surface and sidewalls; and

[0212] The upper surface and at least some sidewalls are treated with a processing plasma, which includes a plasma processing gas that does not contain silicon precursor gas.

[0213] 81. The unit according to any one of the listed embodiments 1-31, wherein the space between the plurality of lithium storage layer segments is 0.01-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35%, 35-40% of the negative electrode surface area or any combination thereof.

[0214] 82. A unit according to any one of the listed embodiments 1-31 and 81, wherein a plurality of lithium storage layer segments are defined by a spacing within the following ranges: 0.2-0.5 nm, 0.5-1.0 nm, 1-2 nm, 2-5 nm, 5-10 nm, 10-20 nm, 20-50 nm, 50-100 nm, 100-200 nm, 200-300 nm, 300-500 nm, 500-700 nm, 700 nm-1 μm, 1-2 μm, 2-3 μm, 3-5 μm, 5-7 μm, 7-10 μm, 10-12 μm, 12-15 μm, 15-20 μm, or any combination of such ranges.

[0215] The specific details of a particular embodiment can be combined in any suitable manner without departing from the spirit and scope of the embodiments of the invention. However, other embodiments of the invention may relate to specific embodiments associated with each individual aspect or a particular combination of these individual aspects.

[0216] For purposes of illustration and description, the foregoing description of exemplary embodiments of the invention has been presented. It is not intended to be exhaustive or to limit the invention to the precise forms described, and many modifications and variations are possible in accordance with the foregoing teachings.

[0217] In the foregoing description, numerous details have been set forth for illustrative purposes to provide an understanding of various embodiments of the present technology. However, it will be apparent to those skilled in the art that certain embodiments can be practiced without some of these details or with additional details.

[0218] Several embodiments have been described, and those skilled in the art will recognize that various modifications, alternative constructions, and equivalents can be used without departing from the spirit of the invention. Furthermore, to avoid unnecessarily obscuring the invention, many well-known methods and elements have not been described. Additionally, details of any particular embodiment may not always be present in variations of that embodiment, or may be added to other embodiments.

[0219] Where a range of values ​​is provided, it should be understood that, unless the context explicitly specifies otherwise, each intermediate value between the upper and lower limits of the range is also specifically disclosed, up to one-tenth of the unit of the lower limit. This encompasses each smaller range between any stated value or intermediate value in the range and any other stated value or intermediate value in the range. The upper and lower limits of these smaller ranges may be independently included in or excluded from the range, and each range that includes any limit value, excludes any limit value, or includes two limit values ​​is also covered within the invention, subject to any specifically excluded limit value within the range. Where the range includes one or both limit values, ranges that exclude any one or both of the included limit values ​​are also included.

[0220] As used herein and in the appended claims, unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” include plural references. Thus, for example, a reference to “a method” includes multiple such methods, and a reference to “negative electrode” includes a reference to more than one negative electrode and its equivalents known to those skilled in the art, and so on. The invention has now been described in detail for purposes of clarity and understanding. However, it should be understood that certain changes and modifications may be practiced within the scope of the appended claims.

[0221] For all purposes, all publications, patents, and patent applications cited herein are incorporated herein in their entirety by reference. None are considered prior art.

Claims

1. A lithium-ion battery cell, comprising: The negative electrode comprises a porous lithium storage layer disposed on a negative electrode current collector and a modification layer disposed on the lithium storage layer. in: i) The lithium storage layer comprises at least 40 atomic percent silicon, tin, germanium, or a combination thereof; ii) The lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments, each of which has an upper surface and a sidewall; and iii) The modified layer is disposed on the upper surface and at least partially along the sidewall; The positive electrode contains a layer of positive electrode active material that is in electrical contact with the positive electrode current collector; and A lithium-ion-containing solid electrolyte (SSE) is situated between the lithium storage layer and the positive electrode active material layer.

2. The unit according to claim 1, wherein the modified layer has a multilayer or gradient structure.

3. The unit according to claim 1, wherein the modified layer comprises silicon oxide, silicon nitride, or silicon oxynitride.

4. The unit according to claim 1, wherein the modified layer comprises silicate.

5. The unit according to claim 1, wherein the modified layer comprises a metal oxide.

6. The unit according to claim 1, wherein the modified layer comprises titanium oxide, aluminum oxide, zirconium oxide, zinc oxide or nickel oxide.

7. The unit according to claim 1, wherein the modified layer comprises a titanium-based organic-inorganic hybrid film, an aluminum-based organic-inorganic hybrid film, a zirconium-based organic-inorganic hybrid film, or a zinc-based organic-inorganic hybrid film.

8. The unit according to claim 1, wherein the modified layer comprises lithium phosphate, lithium aluminum oxide, and Li. x Si y Al2O3 or lithium phosphorus oxynitrate (LiPON).

9. The unit of claim 1, wherein the modified layer is formed at least in part by exposing the lithium storage material to a plasma comprising a fluorinated or perfluorinated carbon material or formed of a fluorinated or perfluorinated carbon material.

10. The unit according to claim 9, wherein the modified layer comprises a fluorine-containing compound.

11. The unit of claim 1, wherein the modified layer is configured to enhance lithium-ion conduction between the SSE and the lithium storage layer segment.

12. The unit of claim 1, wherein the lithium storage layer comprises at least 80 atomic percent amorphous silicon.

13. The unit of claim 1, wherein the lithium storage layer comprises a silicon substoichiometric nitride.

14. The unit according to claim 13, wherein the ratio of nitrogen to silicon is in the range of 0.02 to 0.

5.

15. The unit of claim 1, wherein the lithium storage layer is substantially free of carbon-based binders and conductive carbon.

16. The unit of claim 1, wherein the surface of at least some of the internal pores of the lithium storage layer comprises an internal modification layer.

17. The unit of claim 16, wherein the internal modified layer comprises a metal oxide or silicon oxide.

18. The unit of claim 1, wherein the SSE comprises a solid polymer electrolyte.

19. The unit of claim 1, wherein the SSE comprises a solid inorganic electrolyte.

20. The unit of claim 1, wherein the SSE comprises a solid sulfide electrolyte.

21. The unit according to claim 1, wherein the SSE comprises a lithium-silver-germanium solid electrolyte, a lithium-silicon sulfide solid electrolyte, or a lithium-silicon sulfide solid electrolyte.

22. The unit of claim 1, wherein the positive electrode comprises a lithium metal oxide, wherein the metal comprises cobalt, nickel, manganese or any combination thereof.

23. The unit of claim 1, further comprising a compression system configured to apply a compressive force between the negative electrode and the positive electrode.

24. The unit according to claim 1, wherein the space between the plurality of lithium storage layer segments is 0.01% to 30% of the negative electrode surface area.

25. The unit of claim 1, wherein the plurality of lithium storage layer segments are defined with a spacing in the range of 0.2 nm to 5 μm.

Images