Solid-state lithium-ion batteries

Abstract

A lithium-ion battery cell includes an anode including a porous lithium storage layer disposed over an anode current collector and a modification layer provided on the lithium storage layer. The cell further includes a cathode having a cathode active material layer in electrical contact with a cathode current collector and a lithium-ion-containing solid-state electrolyte (SSE) that is interposed between the lithium storage layer and the cathode active material. The lithium storage layer includes at least 40 atomic % 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 a sidewall. The modification layer is disposed on the upper surface and at least partially along the sidewall.

Description

SOLID-STATE LITHIUM-ION BATTERIESCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 615.911 filed December 29. 2023, entitled ‘‘SOLID-STATE LITHIUM-ION BATTERIES”, the entire contents of which is incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

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

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

[0004] The expansion and contraction of silicon-containing anodes pose additional challenges for making solid-state battery cells.

[0005] Despite research into various approaches, batteries based primarily on silicon, particularly those using solid-state electrolytes, have yet to make a large market impact due to unresolved problems.BRIEF SUMMARY

[0006] There remains a desire for solid-state lithium-ion batteries based on silicon anodes that are easy to manufacture, safer, robust to handling, high in charge capacity, amenable to fast charging, and have good cycle life.

[0007] In accordance with an embodiment of this disclosure, a lithium-ion battery cell includes an anode including a porous lithium storage layer disposed over an anode current collector and a modification layer provided on the lithium storage layer. The cell further includes a cathode having a cathode active material layer in electrical contact with acathode current collector and a lithium-ion-containing solid-state electrolyte (SSE) that is interposed between the lithium storage layer and the cathode active material. The lithium storage layer includes at least 40 atomic % 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 a sidewall. The modification layer is disposed on the upper surface and at least partially along the sidewall.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 A is a cross-sectional view of a non-limiting example of an anode.

[0009] FIG. IB is a cross-sectional view corresponding to the dashed circle B of FIG.1A.

[0010] FIG. 1C is a cross-sectional view of a non-limiting example of a lithium-ion batten' (LIB) cell.

[0011] FIG. ID is a cross-sectional view corresponding to the dashed circle D of FIG. 1C.

[0012] FIG. IE a is top view of a non-limiting example of a segmented lithium storage layer.DETAILED DESCRIPTION

[0013] It is to be understood that the drawings are for purposes of illustrating the concepts of the disclosure and may not be to scale. Terms like '‘overlaying”, “over” or the like include, but do not necessarily require, direct contact (unless such direct contact is noted or clearly required for functionality). Herein, an “average” may represent a mean, median, or mode, and an “average thickness” may be based on at least three measurements. Additional details of certain embodiments of the present application may be found in U.S. Patent Application Publication No. 2019 / 0267631, U.S. Patent Application Publication No. 2020 / 0411851, U.S. 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 Number WO2023 / 113813, U.S. PatentApplication Publication No. 2022 / 0344627, PCT International Publication Number WO2023 / 129408. PCT International Publication Number WO2023 / 239599. PCT International Publication number WO2024 / 058845, PCT International Publication number WO2024 / 173383, and PCT International Publication number WO2024 / 173390, the entire contents of which are incorporated herein by reference for all uses.

[0014] Lithium-ion batteries (LIBs) of the present disclosure may include an anode, a cathode and a solid-state electrolyte ("SSE") interposed between the anode and the cathode. The anode includes a lithium storage layer that may in some cases include a plurality of lithium storage layer segments. In some cases, such segments may be silicon- containing lithium storage segments. In some preferred cases, the SSE may be based on a solid sulfide material. As discussed elsewhere, the lithium storage layer, e g., a silicon- containing lithium storage layer, may in some cases include a modification layer on the surface of the lithium storage layer and interposed between the SSE and the lithium storage layer. In some examples, 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 nevertheless changes the surface properties of the lithium storage layer as discussed elsewhere herein.

[0015] FIG. 1 A is a cross-sectional schematic of anon-limiting example of an anode 100. Anode 100 includes a segmented lithium storage layer 107 including a plurality of lithium storage layer segments, 107-1, 107-2, 107-3, and 107-4, defined by gaps or discontinuities 117. In some examples, the discontinuities may extend through some or all of the lithium storage layer in an average direction approximately orthogonal to the current collector surface, e.g., within 30° of orthogonal. In an SEM cross-section, a discontinuity may appear as a crack or fissure between segments. Although illustrated as straight lines, discontinuities 117 may be appear as crooked lines. A complete discontinuity may be when there is no physical contact between adjacent segments. In some examples, a segment may partially be in physical contact with an adjacent segment, but the connectivity may be weaker along the discontinuity' than the lithium storage material connectivity within a segment. That is, the discontinuity may be partial. Partial discontinuities may include some bndging regions corresponding to where lithium storage layer material connects one segment to another. Partial physical contact may include spaced apart segments having less than 50%, 40%, 30%, 20%, or 10% of the thickness of the segment in physical contact. Anode 100 includes a current collector 101 which mayinclude an electrically conductive layer 103 and optionally a surface layer 105 interposed between the electrically conductive layer 103 and the segmented lithium storage layer 107.

[0016] The segments of the segmented lithium storage layer may be characterized by an average lateral width LW and average thickness T. Referring again to FIG. 1 A as an example, lithium storage layer segment 107-3 along this x-y plane has a lateral width LW. An average lateral width LW for this segment may correspond to the mean of at least 2 measurements along the x-axis from one end of the segment to the other, made at different z-axis positions. Similarly, an average thickness T for this segment may correspond to the mean of at least 2 measurements along the z-axis from the current collector to the top of lithium storage layer (or, if present, to the top of the modification layer 108), made at different x-axis positions.

[0017] Anode 100 having lithium storage layer segments may in some cases be formed directly upon PVD or CVD (preferably PECVD) deposition of the lithium storage layer material. For example, the properties of the current collector may induce such segmentation. For example, the presence of grooves, ridges, dendrites, patterned surface layer, may readily cause some discontinuities during PVD or CVD deposition. The deposition conditions may also affect development of such discontinuities. In some examples, the lithium storage layer may include silicon, germanium, tin, or alloys thereof. In some examples the lithium storage layer is a silicon-containing lithium storage layer including at least 40 atomic % silicon, alternatively at least 80 atomic % silicon or even at least 90 atomic % silicon. The lithium storage layer segments are porous and preferably include porous silicon (including micropores and / or nanopores).

[0018] FIG. IB approximately corresponds to the dashed circle B of FIG. 1 A. The lithium storage layer may further include a modification layer at its surface that may also extend at least partway down / into any discontinuities if present. For example, modification layer 108-1 and 108-2 (which may be referred to herein collectively as modification layer 108) is shown provided over lithium storage layer segments 107-1 and 107-2, both on the segment upper surfaces (parallel to x-axis) and also along their edges (parallel to z-axis) corresponding to discontinuity 117. Although shown as separated in this cross-sectional schematic, the modification layers 108-1 and 108-2 may in some cases bridge and merge together. Although shown as substantially continuous, the modification layer may be patchy or discontinuous. Although shown as a single layer, the modification layer mayinclude multiple layers having different chemical compositions or a gradient structure where the chemical composition changes as a function of depth.

[0019] A modification layer is conductive to lithium ions but has low electrical conductivity. Such properties may reduce the decomposition of the SSE at or near the interface with the anode and / or limit the thickness of the solid electrolyte interface (SEI) that can build up between the anode and the SSE during operation of the LIB cell. In some examples, the lithium-ion conductivity of a modification layer is at least 10’9S / cm, alternatively at least IO’8S / cm, alternatively at least 10‘7S / cm, alternatively at least 10'6S / cm.

[0020] FIG. 1C is a cross-sectional view of an LIB cell according to some examples. Cell 165 includes anode 100, a cathode 140, and a solid-state electrolyte C‘SSE"’) 130 disposed between the anode and the cathode. Anode 100 may be as described with respect to FIG. 1 A. Cathode 140 may include a cathode current collector 143 and a cathode active material layer 147 disposed in contact with the cathode current collector facing the lithium storage layer 107. The solid-state electrolyte includes lithium ions and is described in more detail elsewhere herein. In some preferred examples, the SSE is a solid sulfide. FIG. ID approximately corresponds to the dashed circle D of FIG. 1C to illustrate the interface of the SSE 130 with anode 100, in particular, the modification layer (108-1, 108-2) interposed between the SSE and the lithium storage layer (segments 107-1, 107-2). In this embodiment, SSE 130 does not extend substantially into discontinuity 117. The degree to which the SSE extends into the discontinuities depends on many factors including, but not limited to, dimensions of the discontinuities and the viscosity of the SSE upon application. In particular, it can be difficult for many inorganic SSE materials (such as solid sulfides) to extend into the discontinuities, especially discontinuities having narrow width.

[0021] Materials, methods, and properties relating to the modification layer are discussed elsewhere herein, but it is noted that the process used to make it may, with respect to the underlying lithium storage layer material, include additive, transformative, or subtractive steps, or even a combination thereof. Although the discussion below uses silicon as an example, the same concepts may be applied to other lithium storage materials such as germanium, tin. and / or indium. In some preferred cases, the lithium storage layer is substantially free of carbon-based binders, graphitic carbon, graphene, graphene oxide, reduced graphene oxide, carbon black and conductive carbon.

[0022] An additive process may deposit a new material onto the silicon. Such new material may be the modification layer or a precursor thereto. A few non-limiting examples may include sputtering, evaporative deposition, CVD (which may be PECVD or iCVD), atomic layer deposition (ALD), spatial ALD (S-ALS), molecular layer deposition (MLD), ion-beam deposition, spray coating, dip coating, roll coating, doctor blade coating, inkjet printing, flexographic printing, gravure printing, or some other deposition method.

[0023] A transformative process may involve a chemical reaction where a portion of the silicon originally provided as part of the lithium storage layer becomes part of the modification layer. It may include reactions to transform some of the silicon near the surface to a silicon dioxide (beyond the native oxide that may be present by simple air oxidation at room temperature), a silicon nitride, a silicon oxynitride, a silicate or another silicon-containing compound. In such a transformative process, silicon is no longer in a zero valent oxidation state. In some cases, some or all of the silicon may be in in its (IV) oxidation state, but in other cases, some or all may be in an intermediate oxidation state. In some cases, the transformative process involves treatment of the lithium storage layer with a reactive gas optionally at elevated temperatures. Alternatively, the process may involve contact of the lithium storage layer with a reactive liquid, solution, or mixture, optionally at elevated temperatures. In some cases, the process may involve contact with a treatment plasma including, or formed from, a plasma treatment gas. The plasma treatment gas may in some cases include hydrogen, nitrogen, oxygen, argon, a fluorocarbon or other fluorine- containing molecule, a halogen-containing molecule, a boron-containing molecule, a carbon-containing molecule, a phosphorous -containing molecule, a sulfur-containing molecule, or an oxygen-containing molecule, or any combination thereof. Note that a ‘‘treatment plasma” is for treating the lithium storage layer material after most or all of the lithium storage layer material has been formed. As such, a plasma treatment gas generally does not include substantial amounts of anode active material precursor gases (e.g., silane). For example, if used at all, an anode active material precursor gas constitutes less than 10%, alternatively less than 5%, or even less than 1%, wherein the % may refer to a molar percentage of all gases, or alternatively, to the volumetric rate of addition in mL / min of gases to the plasma chamber. There is no particular limitation on the type of plasma equipment used to generate a treatment plasma, but a treatment plasma is generally gaseous and formed by exposing the plasma treatment gas to energy7of some type (e.g., electrical, electromagnetic, or the like) capable of ionizing the plasma treatment gas.Depending on the particular system, a treatment plasma may be at about atmospheric pressure (e.g.. 80 - 120 kPa), reduced pressure (less than 80 kPa), or elevated pressure (greater than 120 kPa).

[0024] A subtractive process involves removal of some of the lithium storage layer material near exposed surfaces, e.g., by plasma etching, ion milling, chemical etching, or some other etching method. With plasma etching, the plasma treatment gas may in some cases include hydrogen, nitrogen, oxygen, argon, a fluorocarbon or other fluorine- containing molecule, a halogen-containing molecule, a boron-containing molecule, a carbon-containing molecule, a phosphorous -containing molecule, a sulfur-containing molecule, or an oxygen-containing molecule, or any combination thereof. In some cases, the plasma treatment gas may include a tetrafluoromethane or some other fluorinated or perfluorinated carbon-containing material, optionally in combination with oxygen. Chemical etching may in some cases include a mixture of aqueous hydrogen fluoride and silver nitrate, or alternatively an alkaline solution (e.g., of KOH), organic etching agents (e.g., choline), or hydrogen sulfide gas.

[0025] 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 may be modified. For example, the surface roughness may increase. Alternatively, or in addition, the surface energy' (hydrophobicity) may increase or decrease. For example, the surface of the treated lithium storage material may include a monolayer or sub-monolayer of chemical functional groups. Such functional groups may. in some non-limiting examples, include a hydroxyl (-OH) moiety, a hydroperoxy moiety (- OOH), a halo moiety (e.g., -F, -Cl, -Br, or -I), a carbon-containing moiety (such as an alkyl, an alkenyl, a carboxyl, or the like), a nitrogen-containing moiety' (such as an amine, an imine, an amide, an azo, or the like), a sulfur-containing moiety (such as a sulfydryl, a sulfide, a disulfide, a sulfonate, or the like), a phosphorous-containing moiety (such as a phosphino, a phosphono, a phosphate, or the like), a boron-containing moiety (a borono, a borino, a borinate, or the like), or a siloxane-containing moiety'. Such a treated lithium storage layer may be referred to as having a chemically-modified surface. For convenience, a chemically-modified surface is included herein as a type of modification layer.

[0026] Depending on the treatment, a surface region of the lithium storage material may also react to form the modification layer. Alternatively, or in addition, a modification layer may be provided over the etched lithium storage layer by a transformative process and / or an additive process. A subtractive process may in some cases also increase the surface roughness of the lithium storage layer which may increase adhesion of the SSE, increase effective surface area of contact with the SSE, provide additional access to internal porosity for further modification, or any combination. Alternatively, subtractive process may be planarizing to create a more flat silicon surface that may improve lamination of the SSE.

[0027] In some cases, the modification layer may modify the surface properties of the lithium storage layer. For example, silicon is known in the semiconductor field to have a variety of surface states. Without being bound by theory, the authors believe that the surface state can affect electrochemical reduction of lithium ions to lithium metal, the alloying rate of the lithium metal into the silicon, or lithium-ion diffusion in the SEI or SSE adjacent to the silicon, or a combination thereof.

[0028] In some examples, the modification layer lowers the overpotential for lithium- ion reduction and / or increases the alloying rate of lithium metal into the silicon. In some examples, the modification layer may enhance lithium-ion conduction from the SSE to the silicon as compared to a lithium storage layer without the modification layer. For example, “vertical” Li-ion conductivity may be enhanced corresponding to Li-ion diffusion in a direction approximately normal to a silicon surface covered by the modification layer. Alternatively, or in addition, “lateral” Li-ion conductivity may be enhanced corresponding to Li-ion diffusion in a direction approximately parallel to a silicon surface covered by the modification layer. Lateral Li-ion conductivity enhancement may be particularly useful to promote diffusion of lithium ions into discontinuities so that lithiation and delithiation of the anode is not solely through its top surface (as in FIG. ID). Enhanced lateral Li-ion conductivity may in some cases increase the effective surface area of the silicon to allow faster charging / discharging.

[0029] In some cases, the modification layer has a multilayer structure where the modification sublayer in contact with the silicon lowers the overpotential for lithium-ion reduction and / or increases the alloying rate of lithium metal into the silicon, while themodification sublayer adjacent the SSE enhance lithium-ion conduction from the SSE to the silicon (vertically or laterally).

[0030] In some examples, the modification layer promotes adhesion, coating, or lamination of the SSE to the anode which may result in better cell performance or reduced manufacturing costs.

[0031] In some examples, the modification layer protects the silicon surface from coming into direct contact with contaminants or degradation products from the SSE such as sulfides, free thiosulfate, or the like. In some cases, the modification layer is sacrificial in nature.

[0032] In some examples, forming a modification layer modifies the surface states at the silicon / modification layer interface (interface states). For example, there may be fewer electron-poor defects (e.g., from hydrogen atoms) at or near the silicon surface. Similarly, there may be more electron-rich defects (e.g., from oxygen, nitrogen). This may result in faster or longer distance lithium-ion diffusion.

[0033] In some cases, a modification layer may include an oxide, nitride, or oxynitride of silicon. In some examples, the modification layer may include metal oxides, metal nitrides, or metal oxynitrides, e.g., those containing aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel, or tin, or mixtures thereof. The metal oxide, metal nitride or metal oxynitride may include other components such as phosphorous or silicon. In some cases, zinc oxide may scavenge sulfide ion that may be unintentionally released from the SSE to reduce unwanted interactions with the silicon. In some examples, a modification layer may include an inorganic-organic hybrid structure having alternating sublayers of metal oxide and bridging organic materials such as so-called "nietalcone” materials (e.g., zincone, titanicone, alucone, or zircone). The modification layer may include a lithium-containing material such as lithium phosphorous oxynitride (LIPON), lithium phosphate, lithium aluminum oxide, or LixSiyAhOs (where x and y are not zero). The thickness of a modification layer may in some cases be as low as a single monolayer. The thickness of a modification layer may in some cases be in a range of 0.2 - 0.3, 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 ranges thereof, or even in some cases thicker than 100 nm. In some cases, a modification too thin, e.g., below about 0.2 or 0.3 nm, may not provide the desired benefits as described above. In some cases, amodification layer that is too thick, e.g., above 100 nm, may cause unwanted problems such as increased resistance or slower charge / discharge rates. The particular range depends in part upon the modification layer and the desired performance features of the LIB cell.

[0034] FIG. IE a is top view of a non-limiting example of a segmented lithium storage layer 107’ including a plurality lithium storage segments 107-x’ and where the dark lines 106 represent the segment spaces. For clarity, other lithium-ion batter}’ components are not shown. In some examples, segment spaces may account for 0.01 - 5% of the anode surface area, alternatively 5 - 10%, 10 - 15%, 15 - 20%, 20 - 25%, 25 - 30%, 30 - 35%, or 35 - 40% of the surface area, or any combination of ranges thereof.

[0035] FIG. IE illustrates a generally random pattern of lithium storage segments. In some other embodiments (not illustrated), the pattern may be more uniform, geometric, or even partially or fully predetermined.

[0036] In some examples, for the majority of lithium storage segments within at least one 1 mm by 1 mm area of the anode, a ratio of the average lateral width LW of a lithium storage layer segment to the average thickness T of the lithium storage layer segment, e.g., the ratio of LW / T may be at least 0.3. In some examples, such ratio of LW / T may be less than 50. In some examples, the ratio of or LW / T may be in a 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 combinations of ranges thereof, or even higher than 50. In some cases, a ratio of LW / T that is too low, e.g. less than 0.3, may result in a lithium storage layer that has less physical durability or potentially has less lithium storage capacity. In some cases, a ratio of LW / T that is too high, e.g., greater than 50 may result in segments that are more prone to pulverize and detach from the current collector. The particular range depends in part on other aspects of the lithium storage layer and the desired performance features of the LIB cell.

[0037] Lithium storage layer segments may in some cases have a spacing S measured in a dimension parallel to the current collector) in a 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 - 300nm, 300 - 500 nm, 500 - 700 nm, 700 nm - 1 pm, 1 - 2 pm. 2 - 3 pm, 3 - 5 pm, 5 - 7 pm, 7 - 10 pm, 10 - 12 pm, 12 - 15 pm. 15 - 20 pm, or any combination of ranges thereof. S may optionally be measured at the midpoint of the average thickness T of the lithium storage layer, or alternatively, at a position about T / 5 down from the lithium storage surface. S may optionally correspond to an average of at least 2 measurements, e.g., spacings between at least 3 segments along a linear cross-section. In some cases, e.g., when measured across a 1 mm cross-section distance of the anode, the sum of individual spaces S may account for a total of 0.01 - 5% of the cross-section distance, alternatively 5 - 10%, 10 - 15%, 15 - 20%, 20 - 25%, 25 - 30%, 30 - 35%, or 35 - 40% of the crosssection distance, or any combination of ranges thereof.

[0038] Further, it should be appreciated that anodes and cathodes are often coated on both sides of their respective current collector with their respective battery-active material (e.g., a lithium storage layer for the anode and cathode active material for the cathode). Although the figures illustrate single-sided anode and cathode structures, similar teachings can be applied to anodes and cathodes coated on both sides of their respective current collectors.

[0039] While the modification layer has been discussed with respect to the top surface of the lithium storage layer and sidewalls of lithium storage layer segments formed by discontinuities, the disclosed materials and methods may also be used to form modification layer types of materials within a lithium storage layer segment (“internal modification layer”). For example, the porous lithium storage layer (e.g., silicon) may include sufficient random narrow pathways (nano-pathways) to allow modification internally on silicon-containing “walls” or features defining the nano-pathways and pores. This may create an interconnected internal 3D network for lithium-ion transport to allow improved performance by enhancing lithium-ion diffusion into the silicon segment itself by leveraging lateral Li-ion conductivity. In some cases, lithium ions diffuse through interface states between the silicon and, e.g., a silicon oxide-based internal modification layer such as SiCL. Alternatively, a metal oxide or another modification layer material described herein may be used as an internal modification layer. Such internal modification layer may, for example, be provided by treatment of the anode with a gas, plasma, or liquid that contains the desired internal modification layer material or precursor. In some cases, ALD may be used. In some cases, an internal modification layer may not extendfully through the silicon, e.g., it may be more prevalent near the silicon surface and less so (or absent) near the current collector.

[0040] The total and diffuse reflectance properties of the anode can be measured by well-known conventional methods. The total reflectance (Rt) is the sum of the specular reflectance (Rs) and diffuse reflectance (Rd). Measurement of reflectance at 550 nm provides a convenient metric. It has been found that, in some cases, anodes falling within certain reflectance metrics provide surprisingly superior compatibility in solid state cells. In some cases, the anode may have a total reflectance in a range of 8% to 30% (alternatively 9% to 22%) and a ratio of total to diffuse reflectance ratio of less than 1.05 (alternatively 1.03 or less), wherein the total reflectance and diffuse reflectance are measured at 550 nm at a side of the anode having the lithium storage layer. Without being bound by theory, it may be that at a total reflectance of less than 8% may suggest the presence of undesirable nanostructures which may result in anodes that are not robust to handling during cell build. At total reflectance higher than 30% may indicate that the surface of the lithium storage layer is too smooth, or alternatively has a non-ideal chemical composition or physical structure, that leads to poor adherence in the cell, especially those using solid-state electrolytes. Having a total-to-diffuse ratio of less than 1.05 may indicate sufficient roughness at the lithium storage layer surface for making good contact with the SSE. In some cases, the treatments and / or modification layer discussed herein may provide the anode with the noted reflectance. In some cases, the deposition conditions of the silicon alone may be sufficient to produce an anode with the noted reflectance properties without necessarily requiring a post treatment or modification layer.

[0041] Anode

[0042] Current Collector

[0043] In some examples, the current collector or the electrically conductive layer may be characterized by a tensile strength Rm or a yield strength Re. In some cases, the tensile and yield strength properties of the cunent collector are dependent primarily on the electrically conductive layer, which in some examples, may be thicker than the optional surface layer. If the tensile strength is too high or too low, it may in some cases be difficult to handle in manufacturing such as in roll-to-roll processes. During electrochemical cycling of the anode, deformation of the anode may occur if the tensile strength is too low,or alternatively, adhesion of the lithium storage layer may be compromised if the tensile strength is too high.

[0044] Deformation of the anode is not necessarily a problem for all products, and such deformation may sometimes only occur at higher capacities, e.g., higher loadings of lithium storage layer material. For such products, the current collector or electrically conductive layer may in some cases be characterized by a tensile strength Rmin a range of 100 - 150 MPa. alternatively 150 - 200 MPa, alternatively 200 - 250 MPa, alternatively250 - 300 MPa, alternatively 300 - 350 MPa, alternatively 350 - 400 MPa, alternatively400 - 500 MPa, alternatively 500 - 600 MPa, alternatively 600 - 700 MPa, alternatively700 - 800 MPa, alternatively 800 - 900 MPa, alternatively 900 - 1000 MPa, alternatively1000 - 1200 MPa, alternatively 1200 - 1500 MPa, or any combination of ranges thereof.

[0045] In some examples, significant anode deformation should be avoided, but low battery capacities may not be acceptable. For example, in some cases when the anode includes 7 pm or more of amorphous silicon and / or the electrochemical cycling capacity is 1.5 mAh / cm2or greater, a current collector or electrically conductive layer may be selected that is characterized by a tensile strength Rmof 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 may be in a 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 ranges thereof. In some examples, the current collector or electrically conductive layer may have a tensile strength of greater than 1500 MPa. In some examples, the current collector or electrically conductive layer is in the form of a foil having a tensile strength of greater than 600 MPa and an average thickness in a range of 4 - 8 pm, alternatively 8 - 10 pm, alternatively 10 - 14 pm, alternatively 14 - 18 pm, alternatively 18 - 20 pm, alternatively 20 - 25 pm, alternatively 25 - 30 pm, alternatively 30 - 40 pm, alternatively 40 - 50 pm, or any combination of ranges thereof.

[0046] In some examples the electrically conductive layer may have a conductivity of at least 103S / m, or alternatively at least 106S / m, or alternatively at least 107S / m, and mayinclude inorganic or organic conductive materials or a combination thereof. For anodes having low capacity and / or where there are no concerns regarding anode deformation during use, a wide variety of conductive materials may be used as the electrically conductive layer.

[0047] In some examples, the electrically conductive layer includes a metallic material, e.g., titanium (and its alloys), nickel (and its alloys), copper (and its alloys), or stainless steel. In some examples, even metals that may normally react or alloy with lithium, e.g., tin or aluminum, may be suitable if the surface layer is sufficiently protective. In some examples, the electrically conductive layer may include a multilayer structure, e.g., include multiple layers of metal. In some examples, the electrically conductive layer may be a clad foil. In some examples, the electrically conductive layer includes an electrically conductive carbon, such as carbon black, carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, and graphite. In some examples the electrically conductive layer may be in the form of a foil, a mesh, a fiber, a fabric, or sheet of conductive material. Herein, a ‘‘mesh” includes any electrically conductive structure having openings such as found in interwoven wires, foam structures, foils with an array of holes, or the like. In some examples, the electrically conductive layer may include multiple layers of different electrically conductive materials. The electrically conductive layer may be in the form of a layer deposited onto an insulating substrate (e.g., a polymer sheet or ceramic substrate coated with a conductive material, including but not limited to, nickel or copper, optionally on both sides). In some examples, the electrically conductive layer includes a mesh or sheet of electrically conductive carbon, including but not limited to, those formed from bundled carbon nanotubes or nanofibers, or carbon fiber or fabric.

[0048] When higher tensile strength is desirable, e.g., where Rmis greater than 450 MPa, alternatively greater than 500 MPa. alternatively greater than 550 MPa, or alternatively greater than 600 MPa. the electrically conductive layer may include nickel (and certain alloys), or certain copper alloys, such as brass (an alloy primarily of copper and zinc), bronze (an alloy primarily of copper and tin), CuMgAgP (an alloy primarily of copper, magnesium, silver, and phosphorous), CuFe2P (an alloy primarily of copper, iron, and phosphorous), CuNi3Si (an alloy primarily of copper, nickel, and silicon), CuCrZr (an alloy primarily of copper, chromium, and zirconium), and CuCrSiTi (an alloy primarily of copper, chromium, silicon, and titanium). The nomenclature for the metal alloys is not the stoichiometric molecular formula used in chemi stry but rather the nomenclature used bythose of ordinary' skill in the alloy arts. For example, CuNi3Si does not mean there are three atoms of nickel and one atom of silicon for each atom of copper. In some examples these nickel- or copper-based higher tensile electrically conductive layers may include roll-formed nickel or copper alloy foils.

[0049] Alternatively, a mesh or sheet of electrically conductive carbon, including but not limited to, those formed from bundled carbon nanotubes or nanofibers, may in some cases provide for higher tensile strength electrically conductive layers. In some examples, an electrically conductive metal interlayer may be interposed between the electrically conductive carbon and the surface layer.

[0050] In some examples, any of the above-mentioned electrically conductive layers (low or high tensile strength) may act as a primary electrically conductive layer and further include an electrically conductive interlayer, e.g.. a metal interlayer, disposed between the primary electrically conductive layer and the surface layer. For example, an electrically conductive layer may be similar to those described in PCT International Publication Number W02022 / 005999, which is incorporated by reference herein in its entirety for all purposes.

[0051] The metal interlayer may be applied by, e.g., by sputtering, vapor deposition, electrolytic plating, or electroless plating, or any convenient method. The metal interlayer generally has an average thickness of less than 50% of the average thickness of the total electrically conductive layer, e.g., the combined thickness of primary' electrically conductive layer and metal interlay er(s). In some examples, the surface layer may form more uniformly over, or adhere better to. the metal interlayer than to the primary electrically conductive layer.

[0052] General surface roughness

[0053] In some examples, the current collector may be characterized as having a surface roughness. In some examples, and for example top surface of the modification layer 108 of the lithium storage layer 107 may have a lower surface roughness than the surface roughness of current collector 101. Herein, surface roughness comparisons and measurements may be made using the Roughness Average (Ra), RMS Roughness (Rq), Maximum Profile Peak Height roughness (Rp), Average Maximum Height of the Profile (Rz), or Peak Density (Pc). In some examples, the current collector may be characterized as having both a surface roughness Rz> 2.5 pm and a surface roughness Ra> 0.25 pm. Insome examples, Rzis in a range of 2.5 - 3.0 pm, alternatively 3.0 - 3.5 pm, alternatively3.5 - 4.0 pm, alternatively 4.0 - 4.5 pm, alternatively 4.5 - 5.0 pm, alternatively 5.0 - 5.5 pm, alternatively 5.5 - 6.0 pm, alternatively 6.0 - 6.5 pm, alternatively 6.5 - 7.0 pm, alternatively 7.0 - 8.0 pm, alternatively 8.0 - 9.0 pm, alternatively 9.0 to 10 pm, 10 to 12 pm, 12 to 14 pm or any combination of ranges thereof. In some examples, Ra is in a range of 0.25 - 0.30 pm, alternatively 0.30 - 0.35 pm, alternatively 0.35 - 0.40 pm, alternatively 0.40 - 0.45 pm. alternatively 0.45 - 0.50 pm, alternatively 0.50 - 0.55 pm, alternatively0.55 - 0.60 pm, alternatively 0.60 - 0.65 pm, alternatively 0.65 - 0.70 pm, alternatively0.70 - 0.80 pm, alternatively 0.80 - 0.90 pm, alternatively 0.90 - 1.0 pm, alternatively 1.0- 1.2 pm, alternatively 1.2 - 1.4 pm, or any combination of ranges thereof.

[0054] In some examples, some or most of the surface roughness of the current collector may be imparted by the electrically conductive layer and / or a metal interlayer.Alternatively, some or most of the surface roughness of the current collector may be imparted by the surface layer. Alternatively, some combination of the electrically conductive layer, metal interlayer, and surface layer may contribute substantially to the surface roughness.

[0055] In some examples, the electrically conductive layer may include roughening features, e.g., electrodeposited roughening features, to increase surface roughness. In some examples, the electrodeposited roughening features may include copper features. Current collector roughening features may in some cases take the form of nodules, hemispheroids, nanopillars, dendrites, or the like. In some cases, roughening features may be characterized by a height H extending from the electrically conductive layer and a maximum width. In some examples, roughening feature may be characterized by a height H in a range of about 0.1 pm to 0.2 pm, alternatively 0.2 pm to 0.4 pm, alternatively 0.4 pm to 0.6 pm, alternatively 0.6 pm to 0.8 pm, alternatively 0.8 pm to 1.0 pm, 1.0 pm to1.5 pm, alternatively 1.5 pm to 2 pm, alternatively 2 pm to 3 pm, alternatively 3 pm to 4 pm, alternatively 4 pm to 5 pm, or any combination of ranges thereof. In some examples, roughening features may be characterized by a maximum width W in a range of about 0. 1 pm to 0.2 pm, alternatively 0.2 pm to 0.4 pm, alternatively 0.4 pm to 0.6 pm, alternatively 0.6 pm to 0.8 pm, alternatively 0.8 pm to 1.0 pm, 1.0 pm to 1.5 pm. alternatively 1.5 pm to 2 pm, alternatively 2 pm to 3 pm, or any combination of ranges thereof. In some cases, roughening features may be characterized by an aspect ratio H / W in a range of about 0.8 to 1.0, alternatively 1.0 to 1.5, alternatively 1.5 to 2.0, alternatively2.0 to 2.5, alternatively 2.5 to 3, alternatively 3 to 4, alternatively 4 to 5, alternatively 5 to 6, alternatively 6 to 8. alternatively 6 to 10. or any combination of ranges thereof. In some examples, an average 10 pm by 10 pm surface of the electrically 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, alternatively at least 10.

[0056] Alternatively, or in combination with the roughening features, the electrically conductive layer may undergo another electrochemical, chemical, or physical treatment to impart a desired surface roughness prior to formation of the surface layer.

[0057] In some examples, roughening of the electrically conductive layer may include, for example, physical abrasion (such as sandpaper, sand blasting, polishing, or the like), ablation (such as by laser ablation), embossing, stamping, casting, imprinting, chemical treatments, electrochemical treatments, or thermal treatments. In some cases, such roughening may be used to form one or more of the roughening features described above, e.g., nodular features, nanopillar features, broad roughness features, pitted features or the like. In some cases, roughening features may be random, or alternatively, may be patterned.

[0058] Surface layer

[0059] In some examples, a surface layer may provide a chemical composition that promotes formation of an adherent lithium storage layer, such as a lithium storage layer deposited by a CVD or PVD process, particularly at commercially useful loadings or thicknesses of the lithium storage layer. In some cases, deposition onto an electrically conductive layer alone may be insufficient to provide even initial adhesion such that the lithium storage layer material readily brushes or peels off. Even when there is satisfactory initial adherence, it may be insufficient during electrochemical formation and cycling. Some non-limiting examples of surface layers are discussed below. In some cases, a surface layer may include two or more distinct surface sublayers having different chemical compositions. In some cases, a surface layer or even a surface sublayer may include a mixture of different surface layer materials.

[0060] The thickness of a surface layer may be as low as a monolayer in some examples. In some examples, the thickness of the surface layer is in a range of 0. 0.0002 pm to 0.0005 pm. alternatively 0.0005 pm to 0.001 pm, alternatively 0.001 pm to 0.005pm, alternatively 0.002 pm to 0.005 pm, alternatively, 0.005 pm to 0.01 pm, alternatively 0.01 pm to 0.02 pm, alternatively 0.02 pm to 0.03 pm. alternatively 0.03 jun to 0.05 pm, alternatively 0.05 pm to 0. 1 pm, alternatively 0. 1 pm to 0.2 pm, alternatively 0.2 pm to 0.5 pm. alternatively 0.5 pm to 1 pm. alternatively 1 jam to 2 pm. alternatively 2 pm to 5 pm or any combination of ranges thereof.

[0061] In some examples, the surface layer or sublayer may include a metal-oxygen compound. In some cases, a metal-oxygen compound may include a metal oxide or metal hydroxide, e.g., a transition metal oxide or a transition metal hydroxide. In some cases, a metal-oxygen compound may include an oxometallate, e.g., a transition oxometallate. In some examples, a surface layer may include a silicon compound including or derived from a siloxane, a silane (e.g., a silane-containing compound), a silazane, or a reaction product thereof. Herein, a “silicon compound7’ does not include simple elemental silicon such as amorphous silicon. These materials are described in more detail below. In some examples, a surface layer may include a silicate compound. In some examples, a surface layer may include a metal silicide, e.g., a transition metal silicide. In some examples, a surface layer may include a metal chalcogenide such as a metal sulfide, e.g., a transition metal sulfide.

[0062] Lithium Storage Layer / Lithium Storage Layer Segments

[0063] The following discussion may be applicable to either the lithium storage layer segments or to a non-segmented lithium storage layer (or both). For convenience either embodiment is simply referred to as a lithium storage layer in this section. In some examples, the lithium storage layer may be a porous material capable of reversibly incorporating lithium, e.g., continuous porous lithium storage layer. In some examples, the lithium storage layer includes silicon, germanium, antimony, tin, or a mixture of two or more of these elements. In some examples, the lithium storage layer is substantially amorphous. In some examples, a lithium storage layer includes substantially amorphous silicon. Such substantially amorphous storage layers may include a small amount (e.g., less than 20 atomic %) of crystalline material dispersed therein. The lithium storage layer may include dopants such as hydrogen, boron, phosphorous, sulfur, fluorine, aluminum, gallium, indium, arsenic, antimony, yttrium, scandium, bismuth, nitrogen, or metallic elements, or any combination. In some cases, the lithium storage layer includes silicon doped with B (e.g., where B doping may optionally be in a range of 1015- 1022cm’3). Al. Ga, In, Sc, or Y, or any combination. Without being bound by theory, such doping maylower energetic barriers related to electron transport and lithiation. In some examples the lithium storage layer may include porous substantially amorphous hydrogenated silicon (a- Si:H), having, e.g., a hydrogen content of from 0.1 to 20 atomic %, or alternatively higher. In some examples, the lithium storage layer may include methylated amorphous silicon. Note that, unless referring specifically to hydrogen content, any atomic % metric used herein for a lithium storage material or layer refers to atoms other than hydrogen.

[0064] In some examples, the lithium storage layer, e.g.. a continuous porous lithium storage layer, may include at least 40 atomic % silicon, germanium or a combination thereof, alternatively at least 50 atomic %, alternatively at least 60 atomic %, alternatively at least 70 atomic %, alternatively, at least 80 atomic %, alternatively at least 90 atomic %. In some examples, a lithium storage layer, e.g.. a continuous porous lithium storage layer, may include 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 prelithiated anodes as discussed below, the lithium content is excluded from this atomic % characterization.

[0065] In some examples, a lithium storage layer, e g., a continuous porous lithium storage layer, is substantially free (e.g., the lithium storage layer includes less than 1 % by weight, alternatively less than 0.5 % by weight, alternatively less than 0.3% by weight, alternatively less than 0.1% by weight, alternatively less than 0.01% by weight) of carbonbased binders, graphitic carbon, graphene, graphene oxide, reduced graphene oxide, carbon black and conductive carbon. A few non-limiting examples of carbon-based binders may include organic polymers such as those based on styrene butadiene rubber, poly vinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, carboxymethyl cellulose, or polyacrylonitrile.

[0066] The lithium storage layer, e.g., a continuous porous lithium storage layer, may include voids or interstices (pores), which may be random or non-uniform with respect to size, shape, and distribution. Pores may sometimes collectively form random nanopathways within the lithium storage layer that may extend to the surface. In some cases, this porosity may be tuned (e.g., by adjusting deposition conditions) to produce an appropriate surface area for reaction to form interface states or an “internal” modificationlayer (analogous to the modification layer discussed elsewhere) that rapidly transport lithium ions into the bulk of the porous lithium storage layer. In some examples, the effective or specific surface area of the lithium storage layer (e.g., as measured by BET) may be between 2 - 10 m2 / g, alternatively 6 - 10 m2 / g, alternatively 10 - 20 m2 / g, alternatively 20 - 50 m2 / g, alternatively 50 - 100 m2 / g. Such porosity generally does not result in, or result from, the formation of any recognizable high aspect ratio lithium storage nanostructures such as nanowires, nanopillars, or the like. In some examples, the pores may be poly disperse. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, may be characterized as nanoporous. In some examples the lithium storage layer, e.g., a continuous porous lithium storage layer, has an average density in a range of 1.0 - 1.1 g / cm3, alternatively 1.1 - 1.2 g / cm3, alternatively 1.2 - 1.3 g / cm3, alternatively 1.3 - 1.4 g / cm3, alternatively 1.4 - 1.5 g / cm3, alternatively 1.5 - 1.6 g / cm3, alternatively 1.6 - 1.7 g / cm3, alternatively 1.7 - 1.8 g / cm3, alternatively 1.8 - 1.9 g / cm3, alternatively 1.9 - 2.0 g / cm3, alternatively 2.0 - 2.1 g / cm3, alternatively 2.1 - 2.2 g / cm3. alternatively 2.2 - 2.25 g / cm3. alternatively 2.25 - 2.29 g / cm3, or any combination of ranges thereof, and includes 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 a density of less than 2.3 g / cm3is evidence of the porous nature of a-Si containing lithium storage layers.

[0067] In some examples, the majority of active material (e.g., silicon, germanium or alloys thereof) of the lithium storage layer, e.g., a continuous porous lithium storage layer, has substantial lateral connectivity across portions of the current collector creating, such connectivity extending around random pores and interstices. In some examples, the porous lithium storage layer may be described as a matrix of interconnected silicon, germanium or alloys thereof, with random pores and interstices embedded therein. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, may in a cross- sectional view have a sponge-like form. It should be noted that the lithium storage layer, e.g.. a continuous porous lithium storage layer, does not necessarily extend across the entire anode without any lateral breaks and may include random discontinuities or cracks and still be considered continuous. In some examples, such discontinuities may occur more frequently on rough current collector surfaces. In some examples, the lithium storagelayer, e.g., a continuous porous lithium storage layer, may in a cross-sectional view have abutting columns of active material such as silicon. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, may include a matrix of connected nanoparticle aggregates. In some examples, the lithium storage layer may include a mixture of amorphous and crystalline silicon, e.g., nano-crystalline silicon having an average grain size of less than about 100 nm, alternatively less than about 50 nm, 20 nm, 10 nm, or 5 nm. In some cases, the lithium storage layer may include up to 30 atomic % nano-crystalline silicon relative to all silicon in the lithium storage layer.

[0068] In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, includes a substoichiometric oxide of silicon (SiOx), germanium (GeOx) or tin (SnOx) wherein the ratio of oxygen atoms to silicon, germanium or tin atoms is less than 2: 1, e.g., x < 2. alternatively less than 1: 1. e.g., x < 1. In some examples, x is in a 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 ranges thereof.

[0069] In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, includes a substoichiometric nitride of silicon (SiNy), germanium (GeNy) or tin (SnNy) wherein the ratio of nitrogen atoms to silicon, germanium or tin atoms is less than 1.25: 1, e.g., y < 1.25. In some examples, y is in a 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 ranges thereof. Lithium storage layer having a substoichiometric nitride of silicon may also be referred to as nitrogen-doped silicon or a silicon-nitrogen alloy.

[0070] In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, includes a substoichiometric oxynitride of silicon (SiOxNy), germanium (GeOxNy), or tin (SnOxNy) wherein the ratio of total oxygen and nitrogen atoms to silicon, germanium or tin atoms is less than 1 : 1, e.g., (x + y) < 1. In some examples, (x + y) is in a 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 ranges thereof.

[0071] In some examples, the above sub-stoichiometric oxides, nitrides or oxynitrides are provided by a CVD process, including but not limited to. a PECVD process. The oxygen and nitrogen may be provided uniformly within the continuous porous lithiumstorage layer, or alternatively the oxygen or nitrogen content may be varied as a function of storage layer thickness.

[0072] CVD

[0073] CVD generally involves flowing a precursor gas. a gasified liquid in terms of direct liquid injection CVD or gases and liquids into a chamber containing one or more objects, typically heated, to be coated. Chemical reactions may occur on and near the hot surfaces, resulting in the deposition of a thin film on the surface. This is accompanied by the production of chemical by-products that are exhausted out of the chamber along with unreacted precursor gases. As would be expected with the large variety of materials deposited and the wide range of applications, there are many variants of CVD that may be used to form the lithium storage layer, the surface layer or sublayer, a supplemental layer (see below) or other layers. It may be done in hot-wall reactors or cold-wall reactors, at sub-torr total pressures to above-atmospheric pressures, with and without carrier gases, and at temperatures ty pically ranging from 100 - 1600 °C in some examples. There are also a variety7of enhanced CVD processes, which involve the use of plasmas, ions, photons, lasers, hot filaments, or combustion reactions to increase deposition rates and / or lower deposition temperatures. Various process conditions may be used to control the deposition, including but not limited to, temperature, precursor material, gas flow rate, pressure, substrate voltage bias (if applicable), and plasma energy (if applicable).

[0074] As mentioned, a lithium storage layer such as a continuous porous lithium storage layer, e.g., a layer of silicon or germanium or both, may be provided by plasma- enhanced chemical vapor deposition (PECVD). Relative to conventional CVD, deposition by PECVD can often be done at lower temperatures and higher rates, which can be advantageous for higher manufacturing throughput. In some examples, the PECVD is used to deposit a substantially amorphous silicon layer (optionally doped) over the surface layer. In some examples, PECVD is used to deposit a substantially amorphous continuous porous silicon layer over the surface layer.

[0075] In PECVD processes, according to various implementations, a plasma may be generated in a chamber in which the substrate is disposed or upstream of the chamber and fed into the chamber. Various ty pes of plasmas may be used including, but not limited to, capacitively-coupled plasmas, inductively-coupled plasmas, and conductive coupled plasmas. Any appropriate plasma source may be used, including DC, AC, RF, VHF,combinatorial PECVD and microwave sources may be used. In some examples, magnetron assisted RF PECVD may be used.

[0076] PECVD process conditions (temperatures, pressures, precursor gases, carrier gasses, dopant gases, flow rates, energies, and the like) can vary according to the particular process and tool used, as is well known in the art.

[0077] In some implementations, the PECVD process is an expanding thermal plasma chemical vapor deposition (ETP -PECVD) process. In such a process, a plasma generating gas is passed through a direct current arc plasma generator to form a plasma, with a web or other substrate including the current collector optionally in an adjoining vacuum chamber. A silicon source gas is injected into the plasma, with radicals generated. The plasma is expanded via a diverging nozzle and injected into the vacuum chamber and toward the substrate. An example of a plasma generating gas is argon (Ar). In some examples, the ionized argon species in the plasma collide with silicon source molecules to form radical species of the silicon source, resulting in deposition onto the current collector. Example ranges for voltages and currents for the DC plasma source are 60 to 80 volts and 40 to 70 amperes, respectively.

[0078] Any appropriate silicon source may be used to deposit silicon. In some examples, the silicon source may be a silane-based precursor gas including, but not limited to. silane (SiEU), di chlorosilane (EhSiCh), monochlorosilane (EESiCl), trichlorosilane (HSiCh), silicon tetrachloride (SiCU), disilane, tetrafluorosilane, triethylsilane, and diethylsilane. Depending on the gas(es) used, the silicon layer may be formed by decomposition or reaction with another compound, such as by hydrogen reduction. In some examples, the gases may include a silicon source such as silane, a noble gas such as helium, argon, neon, or xenon, optionally one or more dopant gases, and substantially no hydrogen. In some examples, the gases may include argon, silane, and hydrogen, and optionally some dopant gases. In some examples the gas flow ratio of argon relative to the combined gas flows for silane and hydrogen is at least 3.0, alternatively at least 4.0. In some examples, the gas flow ratio of argon relative to the combined gas flows for silane and hydrogen is in a range of 3 - 5, alternatively 5 - 10, alternatively 10 - 15, alternatively 15 - 20, or any combination of ranges thereof. In some examples, the gas flow ratio of hydrogen gas to silane is in a 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 of ranges thereof. Insome examples, higher porosity silicon may be formed and / or the rate of silicon deposition may be increased when the gas flow ratio of silane relative to the combined gas flows of silane and hydrogen increases. In some examples a dopant gas is borane or phosphine, which may be optionally mixed with a carrier gas. In some examples, the gas flow ratio of dopant gas (e.g., borane or phosphine) to silicon source gas (e.g., silane) is in a 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 ranges thereof. Such gas flow ratios described above may refer to the relative gas flow, e.g., in standard cubic centimeters per minute (SCCM). In some examples, the PECVD deposition conditions and gases may be changed over the course of the deposition.

[0079] In some examples, the temperature at the current collector during at least a portion of the time of PECVD deposition is in a range 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 ranges thereof. In some examples, the temperature may vary during the time of PECVD deposition. For example, the temperature during early times of the PECVD may be higher than at later times. Alternatively, the temperature during later times of the PECVD may be higher than at earlier times.

[0080] The thickness or mass per unit area of the lithium storage layer, e.g., a continuous porous lithium storage layer, depends on the storage material, desired charge capacity7and other operational and lifetime considerations. Increasing the thickness typically provides more capacity. If the lithium storage layer becomes too thick, electrical resistance may increase and the stability may decrease. In some examples, the anode may be characterized as having an active silicon areal density of at least 0.2 mg / cm2, alternatively at least 0.5 mg / cm2, alternatively at least 1.0 mg / cm2, alternatively at least 1.5 mg / cm2. alternatively at least 3 mg / cm2, alternatively at least 5 mg / cm2. In some examples, the lithium storage structure may be characterized as having an active silicon areal density’ in a range of 0.2 - 0.5 mg / cm2, alternatively in a range of 0.5 - 1.0 mg / cm2, alternatively in a range of 1.0 - 1.5 mg / cm2, alternatively in a range of 1.5 - 2 mg / cm2, alternatively in a range of 2 - 3 mg / cm2, alternatively in a range of 3 - 5 mg / cm2, alternatively in a range of 5 - 10 mg / cm2. alternatively in a range of 10 - 15 mg / cm2, alternatively in a range of 15 - 20 mg / cm2, or any’ combination of ranges thereof. “Active silicon” refers to the silicon inelectrical communication with the current collector that is available for reversible lithium storage at the beginning of cell cycling, e.g., after anode electrochemical formation. “Areal density” refers to the surface area of the electrically conductive layer over which active silicon is provided. In some examples, not all of the silicon content is active silicon, e.g., some may be tied up in the form of non-active silicides or may be electrically isolated from the current collector.

[0081] In some examples the lithium storage layer, e.g., a continuous porous lithium storage layer, has an average thickness of at least 0.5 pm, alternatively at least 1 pm, alternatively at least 2.5 pm, alternatively at least 5 pm, alternatively at least 6.5 pm. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, has an average thickness in a range of about 0.5 pm to about 50 pm. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, comprises at least 80 atomic % amorphous silicon and / or has a thickness in a range of 1 - 1.5 pm, alternatively 1.5 - 2.0 pm, alternatively 2.0 - 2.5 pm, alternatively 2.5 - 3.0 pm, alternatively 3.0 - 3.5 pm, alternatively 3.5 - 4.0 pm, alternatively 4.0 - 4.5 pm, alternatively 4.5 - 5.0 pm, alternatively 5.0 - 5.5 pm, alternatively 5.5 - 6.0 pm, alternatively 6.0 - 6.5 pm, alternatively 6.5 - 7.0 pm, alternatively 7.0 - 8.0 pm, alternatively 8.0 - 9.0 pm, alternatively 9.0 - 10 pm, alternatively 10 - 15 pm, alternatively 15 - 20 pm, alternatively 20 - 25 pm, alternatively 25 - 30 pm, alternatively 30 - 40 pm. alternatively 40 - 50 pm, or any combination of ranges thereof.

[0082] In some examples, rather than depositing the lithium storage material by CVD or PECVD, it may be formed by a physical vapor deposition (PVD) process such as by sputtering. Although the deposition rates of sputtering are typically lower than PECVD, sputtering may be suitable for some applications, e.g., those that require relatively lower loadings of the active material such as silicon. For example, in some examples, a lithium storage layer, e.g., a continuous porous lithium storage layer, formed by a sputtering process may have a thickness of less than about 15 pm, alternatively less than about 10 pm, alternatively less than 7 pm, alternatively less than 5 pm, alternatively less than 3 pm.

[0083] Other anode features

[0084] The anode may optionally include various additional layers and features. The current collector may include one or more features to ensure that a reliable electrical connection can be made in the energy storage device.

[0085] In some examples, the lithium storage layer may be at least partially prelithiated prior to a first electrochemical cycle after battery assembly, or alternatively prior to battery assembly. That is, some lithium may be incorporated into the lithium storage layer to form a lithiated storage layer even prior to a 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. In some examples, the lithiated storage layer may include lithium in a range of 1% to 5% of the theoretical lithium storage capacity of the lithium storage layer, 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%, or any combination of ranges thereof.

[0086] In some examples prelithiation may include depositing lithium metal over the lithium storage layer, e.g., a continuous porous lithium storage layer, alternatively between one or more lithium storage sublayers, or both, e g., by evaporation, e-beam or sputtering. Alternatively, prelithiation may include contacting the anode with a reductive lithium organic compound, e.g., lithium naphthalene, n-butyl lithium or the like. In some examples, prelithiation may include incorporating lithium by electrochemical reduction of lithium ion in prelithiation solution. In some examples, prelithiation may include a thermal treatment to aid the diffusion of lithium into the lithium storage layer.

[0087] In some examples the anode may be thermally treated prior to battery assembly. In some examples, thermally treating the anode may improve adhesion of the various layers or electrical conductivity, e.g., by inducing migration of metal from the current collector or atoms from the optional supplemental layer into the lithium storage layer.

[0088] In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, includes 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 %, alternatively at least 1 atomic %. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, includes less than about 10 atomic % of one or more transition metals, alternatively less than 5 atomic %, alternative less than 2 atomic %. alternatively less than 1 atomic %. alternatively less than 0.5 atomic %. alternatively less than 3 atomic %. In some examples, the lithium storage layer, e.g., acontinuous porous lithium storage layer, may include one or more transition metals in an atomic % range of 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 ranges thereof. In some examples, the aforementioned ranges of atomic % the transition metal(s) may correspond to a cross-sectional area of the lithium storage layer of at least 1 pm2, which may be measured, e.g., by energy dispersive x-ray spectroscopy (EDS). In some examples, the transition metal atomic % values above may represent the atomic % of one transition metal or alternatively may correspond to the combined atomic % when there is mixture of transition metals. 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 examples, there is a gradient where the concentration of the transition metal in portions of the lithium storage layer near the current collector is higher than portions further from the current collector. In some examples, the lithium storage layer, e.g., a continuous porous lithium storage layer, may include a transition metal that is the same as a transition metal found in the electrically conductive layer or the surface layer transition metallate. In some cases, the one or more transition metals may be provided in the lithium storage layer by thermal treatments to cause migration of the metal into the lithium storage layer, but other methods may be used, such as co-deposition of the lithium storage material and the metal.

[0089] In some examples, thermally treating the anode may be done in a controlled environment having a low oxygen and water (e.g., less than 10 ppm or partial pressure of less than 0.1 Torr, alternatively less than 0.01 Torr content to prevent degradation). In some examples, anode thermal treatment may be carried out using an oven, infrared heating elements, contact with a hot plate or exposure to a flash lamp. The anode thermal treatment temperature and time depend on the materials of the anode. In some examples, anode thermal treatment includes heating the anode to a temperature of at least 50 °C, optionally in a range of 50 °C to 950 °C, alternatively 100 °C to 250 °C, alternatively 250 °C to 350 °C, alternatively 350 °C to 450 °C, alternatively 450 °C to 550 °C, alternatively 550 °C to 650 °C. alternatively 650 °C to 750 °C. alternatively 750 °C to 850 °C. alternatively 850 °C to 950 °C, or a combination of these ranges. In some examples, the thermal treatment may be applied for a time period of 0. 1 to 120 minutes.

[0090] In some examples one or more processing steps described above may be performed using roll-to-roll methods wherein the electrically conductive layer or current collector is in the form of a rolled film, e.g., a roll of metal foil, mesh or fabric.

[0091] SSE

[0092] An SSE material may in some cases be applied to the anode surface by, e.g., extrusion, a coating process (e.g., gravure, slot die, spray, dip coat, inkjet, flexographic, rod, or blade coating methods), lamination of a preformed SSE film, optionally provided on a donor sheet, or some other method. After application, there may in some cases include a heating step (drying, annealing, sintering, or the like). The present anode, which in some preferred embodiments is typically substantially free of binder, is highly compatible with such application methods. Such anodes can tolerate a wide range of solvents and temperatures. In some cases, the SSE material may be first applied to cathode and later contacted with the anode during cell construction. Alternatively, the SSE may be a fee standing film concurrently laminated to the anode and cathode during cell construction. Regardless of the method, in some cases, contacting the SSE to the anode may optionally involve dry and / or anaerobic conditions.

[0093] The solid-state electrolyte includes a source of mobile lithium ions that diffuse between the anode and the cathode (to the anode during charging and away from the anode during discharging). The three main families of SSE are solid polymer electrolytes (SPEs), solid inorganic electrolytes (SIEs), and hybrid SSE which uses both SPE and SIE materials. In some cases, the source of lithium ion may include a lithium salt, which may be in the form of a small molecule (e.g., LiTSFI. LiPFg or any other lithium salt described below) suspended or dissolved in a SSE matrix. In some cases, a SPE material may include an anionic functional group that may act as the lithium salt counterion. The SSE may optionally include plasticizers, rheology control agents, or even a small amount of organic solvent(s).

[0094] A few non-limiting examples of polymeric materials that may be used in the SSE composition include poly(ethylene oxide) (PEO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(trimethylene carbonate), diester- based polymers. PVdF-based polymers, polycaprolactone, and their derivatives or copolymers, which may be used alone or in combination. The polymer of the SSE may in some cases be cross-linked or branched. The polymer may be a block copolymer. Apolymer SSE may be fully amorphous or include some crystallinity'. The polymer may include anionic functional groups.

[0095] A few non-limiting classes of SIE material that may be used in the SSE composition include b-aluminas, LISICONs, thio-LISICONs, NASICONs, perovskites, antiperovskites, garnets, complex hydrides, and solid sulfides.

[0096] A few non-limiting classes of solid sulfides include ceramic sulfides, glass sulfides, and glass-ceramic sulfides. Glass sulfides show minimal long-range order that is identified by the lack of peaks in the pattern resulting from x-ray diffraction (XRD) measurements. Glass-ceramic sulfides include some glass structural regions and some regions wi th long range order that is identified by characteristic peaks in the pattern resulting from XRD measurements. Ceramic sulfides, also known as crystalline sulfides, are composed of regions that have long range order that is identified by characteristic peaks in the pattern resulting from XRD measurements. Non-limiting examples of ceramic sulfides include argyrodites, silicon thiophosphates, and silicon halide thiophosphates. Exemplary', but non-limiting, solid sulfides comprise a thiophosphate (PS4) that may be identified by a characteristic feature in the pattern resulting from measurement with either infrared spectroscopy or Raman spectroscopy. Some additional examples of solid sulfides may' include LiePSsCl, LGPS materials such as LiioGeP2Si2, and LPS materials such as LiyPsSn.

[0097] In some examples, under battery' operating conditions, the SSE may have a lithium-ion conductivity’ in a range of 0.001 mS / cm to 0.01 mS / cm, alternatively in a range of 0.01 mS / cm to 0. 1 mS / cm, alternatively in a range of 0. 1 mS / cm to 1.0 mS / cm, alternatively higher than 1 mS / cm.

[0098] In some examples, the solid-state electrolyte includes a material reversibly transformable from a low flowability state to a high flowability' state and back to a low flowability state. In some cases, this cycle may be available only once and such systems may be referred to as "singly reversible”. For example, an SSE in a first low flowability state may have a first chemical composition or morphology. After the high flowability' state excursion, the SSE may revert to a second low flowability' state and have a second chemical composition or morphology different from the first. For example, the SSE may undergo a polymerization or cross-linking reaction during or after the high flowabilitystate to form the second low flowability state that is no longer as readily transformable to ahigh flowability state. In some other embodiments, the cycle may be repeatable two or more times (“multiply reversible”). In some cases, the low flowability state may correspond to a glassy state or a solid state. In some examples, a high flowability state may correspond to a liquid state. In some examples, a transformation from a low to high flowabili state may approximately correspond to an SSE material’s melting point, or alternatively, to a SSE material’s glass transition temperature (Tg). In some examples, transformation from a low flowability state to a high flowability state may be accomplished by application of energy to the precursor cell so that the temperature of the SSE in the precursor cell is raised to Ti where transformation can occur. The energy' may be applied, for example, by placing the precursor cell in an oven or on a hot plate, exposure to a flash lamp, wrapping the cell in a heating coil, resistive heating of a precursor cell component, micro wave exposure, or some other method. Ti is generally above room temperature. In some examples, Ti may be at least 40 °C, alternatively, at least 50 °C, 60 °C, 80 °C. 100 °C, 125 °C, 150 °C, 175 °C, or 200 °C. In some examples, Ti may be in a range of 40 - 60 °C, alternatively in a range 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 of ranges thereof. In some examples, compression may be applied to the precursor cell (between the anode and cathode) while the SSE is in the high flowability state. Such compression may include a force of greater than 1 bar, alternatively greater than 1.5 bar, 2 bar, 3 bar, 4 bar, 5 bar, 7 bar, or 10 bar. In some cases, the compression is in a 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 of ranges thereof.

[0099] In some examples, a high flowability state may be characterized by a viscosity7lower than 1 MPa-sec, 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, the high flowability' state may be characterized by a viscosity in a range of 0.001 - 0.01 Pa-sec, 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 ranges thereof.

[0100] A low flowability state has a higher viscosity than a high flowability state by’ at least a factor of l. lx, alternatively by at least 1.5x, 2x, 5x, lOx, 20x, 50x, lOOx, 200x,500x, lOOOx, 104x, or 105x. In some examples, a low flowability state may have a viscosity’ of at least 100 Pa-sec. alternatively at least Ik Pa-sec, alternatively at least 10k Pa-sec, alternatively at least 100 kPa-sec, alternatively at least 1 MPa-sec.

[0101] Transformation from the high flowability state to the low flowability state may include active cooling to T2 (or below), e.g., using chillers, heat pumps, or the like to remove heat from the cell. Alternatively, passive cooling may be used where radiative cooling occurs, e.g., when room temperature is at or below T2. In some cases, T2 is less than Ti, e.g., T2 may be 1 - 5 °C lower than Ti, or alternatively 5 - 10 °C lower, 10 - 20 °C lower, 20 - 30 °C lower, 30 - 40 °C low er, 40 - 50 °C lower, 50 - 75 °C lower, 75 - 100 °C lower. 100 - 150 °C lower, or any combination of ranges thereof, or even more than 150°C lower.

[0102] Cathode

[0103] Positive electrode (cathode) active materials include, but are not limited to, lithium metal oxides or compounds (e.g., LiCoCh, LiFePC>4, LiMnCh, LiNiCh, LiMn2O4, LiCoP04, LiNixCoyMnz02, LiNixCoyAlzCh, LiFe2(SO4)s, or Li2FeSiO4), carbon fluoride, metal fluorides such as iron fluoride (FeR). metal oxide, sulfur, selenium and combinations thereof. Cathode active materials may operate, e.g., by intercalation, conversion, or a combination. Cathode active materials may in some cases be mixed with one or more binders and coated to form the cathode. In some cases, the cathode may include polymeric, SIE, or hybrid SSE materials like any of those described elsewhere, and which may be the same as or different than the material used in the SSE layer between the anode and cathode. In some cases, a solid electrolyte used in the cathode may be different than the SSE layer, e.g., it may have lower flowability than the SSE layer.Cathode active materials are typically provided on. or in electrical communication with, an electrically conductive cathode current collector.

[0104] The cathode may optionally be oversized relative to the anode to provide additional lithium inventory'. The additional lithium inventory’ can be electrochemically transferred to the anode and retained in the anode during subsequent battery operation in order to increase the electronic conductivity of the anode.

[0105] Battery Format

[0106] In some examples, batteries can be formed into multilayer stacks of anodes and cathodes, e.g.. as in a pouch cell, a coin cell, or some prismatic cells. Alternatively, anode / cathode stacks can be formed into a so-called jelly-roll and used in a cylindrical cells or some prismatic cells. Such structures are provided into an appropriate housing having desired electrical contacts. A cell may sometimes include a compression system that applies a compressive force between the anode and the cathode. This may sometimes improve cycle life. Such compression system may optionally apply a variable force. A compression system may, for example, include a linear or non-linear spring (or some other component that operates on similar principles).

[0107] Separator

[0108] Although not usually necessary when using an SSE, the battery' may optionally further include a current separator between the anode and cathode. The current separator allows lithium ions to flow between the anode and cathode but prevents direct electrical contact, e.g., when the SSE is in a state of high flowability7. Current separators are ty pically made in the form of a porous sheet of electrically insulative material. In some cases, separators are single layer or multilayer polymer sheets (e.g., based on polyolefins, PET, or PVDF). Separators may alternatively include glass materials, ceramic materials, a ceramic material embedded in a polymer, a polymer coated with a ceramic, or some other composite or multilayer structure, e.g., to provide higher mechanical and thermal stability7. In some cases, a separator may have >30% porosity7, low ionic resistivity7, a thickness of ~ 10 to 50 pm and high bulk puncture strengths.

[0109] Lithium salts

[0110] As mentioned, some SSEs may include one or more lithium salts. A SSE may include one or more of the following non-limiting examples: LiPFe, LiBF4, LiCICU, LiAsF6, LIN(CF3SO2)2, LiN(C2F5SO2)2, LiCF3SO3, LiC(CF3SO2)3, LiPF4(CF3)2, LiPF3(C2Fs)3, LiPF3(CF3)3, LiPF3(iso-C3F7)3, LiPFstiso-QF?). lithium salts having cyclic alkyl groups (e.g.. (CF2)2(SO2)2xLi and (CF2)3(SO2)2xLi), LiFSI (lithium bis(fluorosulfonyl)imide), LiTDI (lithium 4,5-dicyano-2-(trifluoromethyl)imidazole), and combinations thereof. In some examples, the effective concentration of lithium ion in the SSE may be at least 0.3 M, alternatively at least 0.7 M, alternatively at least 1 M, alternatively at least 1.5 M.

[0111] In some examples, the SSE may include a relatively small amount of organic solvent, e.g., for increasing lithium-ion conductivity or simply as a vehicle for adding lithium salts. In some examples, the weight % of solvent 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%. If used at all, some non-limiting examples of non-aqueous solvents suitable for some lithium ion cells include the following: cyclic carbonates (e.g., ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), butylene carbonate (BC) and vinylethylene carbonate (VEC)), vinylene carbonate (VC), lactones (e g., gammabutyrolactone (GBL), gamma-valerolactone (GVL) and alpha-angelica lactone (AGL)), linear carbonates (e.g., dimethyl carbonate (DMC), methyl ethyl carbonate (MEC, also commonly abbreviated 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-di oxane, 1,2- dimethoxyethane (DME), 1,2-di ethoxy ethane and 1,2-dibutoxy ethane), nitriles (e.g., acetonitrile and adiponitrile) linear esters (e.g., methyl propionate, methyl pivalate, butyl pivalate and octyl pivalate), amides (e.g.. dimethyl formamide), organic phosphates (e.g.. trimethyl phosphate and trioctyl phosphate), organic compounds containing an S=O group (e.g., dimethyl sulfone and divinyl sulfone), and combinations thereof.

[0112] In some examples, electrochemical cycling conditions may be set to utilize only a portion of the theoretical charge / discharge capacity of silicon (3600 mAh / g). In some examples, electrochemical charging / discharging cycles may 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 - 2000 mAh / g, alternatively 2000 - 2200 mAh / g, alternatively 2200 - 2400 mAh / g, alternatively 2400 - 2600 mAh / g. alternatively 2600 - 2800 mAh / g, alternatively 2800 - 3000 mAh / g, alternatively 3000 - 3200 mAh / g, alternatively 3200 - 3400 mAh / g, or any combination of ranges thereof.

[0113] Enumerated EmbodimentsEnumerated embodiment 1. A lithium-ion battery' cell including: an anode including a porous lithium storage layer disposed over an anode current collector and a modification layer provided on the lithium storage layer. wherein:i) the lithium storage layer includes at least 40 atomic % silicon, tin, germanium, or a combination thereof; ii) the lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments each having an upper surface and a sidewall; and iii) the modification layer is disposed on the upper surface and at least partially along the sidewall; a cathode including a cathode active material layer in electrical contact with a cathode current collector; and a lithium-ion-containing solid-state electrolyte (SSE) that is interposed between the lithium storage layer and the cathode active material layer.Enumerated embodiment 2. The cell of enumerated embodiment 1. wherein the modification layer enhances lithium-ion conduction between the SSE and the lithium storage layer segments.Enumerated embodiment 3. The cell according to any of the preceding enumerated embodiments, wherein the modification layer lowers the overpotential for lithium-ion reduction, increases the alloying rate of lithium metal into the silicon, or both.Enumerated embodiment 4. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes electron-rich domains that optionally include oxygen.Enumerated embodiment 5. The cell according to any of the preceding enumerated embodiments, wherein the lithium storage layer includes at least 80 atomic % amorphous silicon.Enumerated embodiment 6. The cell according to any of the preceding enumerated embodiments, wherein the lithium storage layer is substantially free of carbon-based binders and conductive carbon.Enumerated embodiment 7. The cell according to any of the preceding enumerated embodiments, wherein the modification layer has a multilayer or gradient structure.Enumerated embodiment 8. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes a silicon oxide, silicon nitride, or silicon oxynitride.Enumerated embodiment 9. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes a silicate.Enumerated embodiment 10. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes a metal oxide.Enumerated embodiment 11. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes titania, alumina, zirconia, zinc oxide, or nickel oxide.Enumerated embodiment 12. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes titanicone. alucone, zircone, or zincone.Enumerated embodiment 13. The cell according to any of the preceding enumerated embodiments, wherein the modification layer includes lithium phosphate, lithium aluminum oxide, LixSiyAhCh, or lithium phosphorus oxynitride (LiPON).Enumerated embodiment 14. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a solid polymer electrolyte.Enumerated embodiment 15. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a solid inorganic electrolyte.Enumerated embodiment 16. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a solid sulfide electrolyte.Enumerated embodiment 17. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a lithium argyrodite solid electrolyte.Enumerated embodiment 18. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a lithium silicon sulfide solid electrolyte.Enumerated embodiment 19. The cell according to any of the preceding enumerated embodiments, wherein the SSE includes a lithium silicon sulfide halide solid electrolyte.Enumerated embodiment 20. The cell according to any of the preceding enumerated embodiments, wherein the modification layer is formed at least in part by an additive process.Enumerated embodiment 21. The cell according to any of the preceding enumerated embodiments, wherein the modification layer is formed at least in part by a transformative process.Enumerated embodiment 22. The cell according to any of the preceding enumerated embodiments, wherein the modification layer is formed at least in part by a subtractive process.Enumerated embodiment 23. The cell according to any of enumerated embodiments 1 - 22, further including a compression system that applies a compressive force between the anode and cathode.Enumerated embodiment 24. The cell according to any of the preceding enumerated embodiments, wherein the lithium storage layer includes a substoichiometric nitride of silicon.Enumerated embodiment 25. The cell of enumerated embodiment 24, wherein the ratio of nitrogen to silicon is in a range of 0.02 to 0.5, optionally in a range of 0.1 to 0.5.Enumerated embodiment 26. The cell according to any of the preceding enumerated embodiments, wherein the modification layer is formed at least in part by exposure of lithium storage material to a treatment plasma including, or formed from, a fluorinated or perfluorinated carbon-containing material.Enumerated embodiment 27. The cell of enumerated embodiment 26, wherein the modification layer includes a fluorine-containing compound.Enumerated embodiment 28. The cell according to any of the preceding enumerated embodiments, wherein the modification layer comprises a metal nitride or metal oxynitride, optionally wherein the metal of the metal nitride or metal oxynitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel, or tin, or a combination thereof.Enumerated embodiment 29. The cell according to any of the preceding enumerated embodiments, wherein surfaces of at least some internal pores of the lithium storage layer include an internal modification layer.Enumerated embodiment 30. The cell of enumerated embodiment 29, wherein the internal modification layer includes a metal oxide or a silicon oxide.Enumerated embodiment 31. The cell according to any of the preceding enumerated embodiments, wherein the cathode includes a lithium metal oxide, wherein the metal includes cobalt, nickel, manganese, or any combination thereof.Enumerated embodiment 32. An anode for a lithium-ion battery, the anode including a porous lithium storage layer disposed over an anode cunent collector, wherein: i) the lithium storage layer includes at least 40 atomic % silicon, tin, germanium, or a combination thereof; ii) the lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments each having an upper surface and a sidewall; andiii) the anode has total reflectance in a range of 8% to 30% and a ratio of total to diffuse reflectance ratio of less than 1.05, wherein the total reflectance and diffuse reflectance are measured at 550 nm at a side of the anode having the lithium storage layer.Enumerated embodiment 33. The anode of enumerated embodiment 32, wherein the total reflectance is in a range of 9% to 22% and the ratio of total to diffuse reflectance is 1.03 or less.Enumerated embodiment 34. The anode according to any enumerated embodiment 32 - 33, wherein the lithium storage layer includes a substoichiometric nitride of silicon.Enumerated embodiment 35. The anode of enumerated embodiment 34, wherein the ratio of nitrogen to silicon is in a range of 0.02 to 0.5, optionally in a range of 0.1 to 0.5.Enumerated embodiment 36. The anode according to any of enumerated embodiments 32 - 35, wherein the lithium storage layer includes at least 80 atomic % amorphous silicon.Enumerated embodiment 37. The anode according to any of enumerated embodiments 32 - 36, wherein the lithium storage layer is substantially free of carbonbased binders and conductive carbon.Enumerated embodiment 38. An anode for a lithium-ion battery, the anode including a porous lithium storage layer disposed over an anode cunent collector, wherein: i) the lithium storage layer includes at least 40 atomic % silicon, tin, germanium, or a combination thereof; ii) the lithium storage layer includes discontinuities defining a plurality7of lithium storage layer segments each having an upper surface and a sidewall; and iii) a modification layer provided on the lithium storage layer, wherein the modification layer is disposed on the upper surface and at least partially along the sidewall.Enumerated embodiment 39. The anode of enumerated embodiment 38, wherein the modification layer lowers the overpotential for lithium-ion reduction, increases the alloying rate of lithium metal into the silicon, or both.Enumerated embodiment 40. The anode of enumerated embodiment 38 or 39, wherein the modification layer includes electron-rich domains that optionally include oxygen.Enumerated embodiment 41. The anode according to any of enumerated embodiments 38 - 40, wherein the lithium storage layer includes at least 80 atomic % amorphous silicon.Enumerated embodiment 42. The anode according to any of enumerated embodiments 38 - 41, wherein the lithium storage layer is substantially free of carbonbased binders and conductive carbon.Enumerated embodiment 43. The anode according to any of enumerated embodiments 38 - 42, wherein the modification layer has a multilayer or gradient structure.Enumerated embodiment 44. The anode according to any of enumerated embodiments 38 - 43, wherein the modification layer includes a silicon oxide, silicon nitride, or silicon oxynitride.Enumerated embodiment 45. The anode according to any of enumerated embodiments 38 - 44, wherein the modification layer includes a silicate.Enumerated embodiment 46. The anode according to any of enumerated embodiments 38 - 45, wherein the modification layer includes a metal oxide.Enumerated embodiment 47. The anode according to any of enumerated embodiments 38 - 46, wherein the modification layer includes titania, alumina, zirconia, zinc oxide, or nickel oxide.Enumerated embodiment 48. The anode according to any of enumerated embodiments 38 - 47, wherein the modification layer comprises a metal nitride or metal oxynitride, optionally wherein the metal of the metal nitride or metal oxynitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel, or tin, or a combination thereof. Enumerated embodiment 49. The anode according to any of enumerated embodiments 38 - 48, wherein the modification layer includes titanicone, alucone, zircone, or zincone.Enumerated embodiment 50. The anode according to any of enumerated embodiments 38 - 49, wherein the modification layer includes lithium phosphate, lithium aluminum oxide, LixSiyA12O3, or lithium phosphorus oxynitride (LiPON).Enumerated embodiment 51. The anode according to any of enumerated embodiments 38 - 50, wherein the anode has total reflectance in a range of 8% to 30% and a ratio of total to diffuse reflectance ratio of less than 1.05, wherein the total reflectance and diffuse reflectance are measured at 550 nm at a side of the anode having the lithium storage layer.Enumerated embodiment 52. The anode of enumerated embodiment 51, wherein the total reflectance is in a range of 9% to 22% and the ratio of total to diffuse reflectance is 1.03 or less.Enumerated embodiment 53. The anode according to any of enumerated embodiments 38 - 52, wherein the lithium storage layer includes a substoichiometric nitride of silicon.Enumerated embodiment 54. The anode of enumerated embodiment 53. wherein the ratio of nitrogen to silicon is in a range of 0.02 to 0.5, optionally in a range of 0. 1 to 0.5.Enumerated embodiment 55. The anode according to any of enumerated embodiments 38 - 54, wherein the modification layer is formed at least in part by exposure of the lithium storage layer to a treatment plasma including, or formed from, a plasma treatment gas, wherein the plasma treatment gas includes hydrogen, nitrogen, a fluorocarbon or other halogen-containing molecule, a boron-containing molecule, a carbon-containing molecule, a phosphorous-containing molecule, a sulfur-containing molecule, or an oxy gen-containing molecule, or any combination thereof..Enumerated embodiment 56. The anode of enumerated embodiment 55, wherein the modification layer includes a fluorine-containing compound.Enumerated embodiment 57. The anode according to any of enumerated embodiments 38 - 56, wherein the modification layer includes one or more functional groups attached to the lithium storage layer at the upper surface and at least partially along the sidewall, optionally wherein at least one functional group includes a hydroxyl moiety, a halo moiety, a carbon-containing moiety7, a nitrogen-containing moiety7, a sulfur- containing moiety, a phosphorous-containing moiety, or a boron-containing moiety.Enumerated embodiment 58. The anode according to any of enumerated embodiments 38 - 57, wherein surfaces of at least some internal pores of the lithium storage layer include an internal modification layer.Enumerated embodiment 59. The anode of enumerated embodiment 58, wherein the internal modification layer includes a metal oxide or a silicon oxide.Enumerated embodiment 60. A lithium-ion battery7cell including the anode according to any of enumerated embodiments 32 - 59, a cathode, and an electrolyte disposed between the anode and the cathode.Enumerated embodiment 61. The lithium-ion battery cell of enumerated embodiment 60, wherein the electrolyte includes a liquid electrolyte.Enumerated embodiment 62. The lithium-ion battery cell of enumerated embodiment 60 or 61, wherein the electrolyte includes a solid-state electrolyte.Enumerated embodiment 63. A method of making an anode for lithium-ion battery cell, the method including: depositing a silicon-containing porous lithium storage layer onto a current collector by a PVD or CVD process, wherein the lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments each having an upper surface and a sidewall; and treating the upper surface and at least some of the sidewall to form a modification layer thereon.Enumerated embodiment 64. The method of enumerated embodiment 63, wherein the treating includes exposing the lithium storage layer to a treatment plasma including, or formed from, a plasma treatment gas.Enumerated embodiment 65. The method of enumerated embodiment 64, wherein the plasma treatment gas includes hydrogen, nitrogen, a fluorocarbon or other halogencontaining molecule, a boron-containing molecule, a carbon-containing molecule, a phosphorous-containing molecule, a sulfur-containing molecule, or an oxy gen-containing molecule, or any combination thereof.Enumerated embodiment 66. The method according to any of enumerated embodiments 63 - 65, wherein the modification layer includes one or more functional groups attached to the lithium storage layer at the upper surface and at least partially along the sidewall.Enumerated embodiment 67. The method of enumerated embodiment 66, wherein at least one functional group includes a hydroxyl moiety, a halo moiety, a carbon- containing moiety, a nitrogen-containing moiety, a sulfur-containing moiety, a phosphorous-containing moiety, or a boron-containing moiety.Enumerated embodiment 68. The method according to any of enumerated embodiments 63 - 67, wherein the modification layer is continuous across each lithium storage layer segment.Enumerated embodiment 69. The method according to any of enumerated embodiments 63 - 68, wherein the modification layer has a multilayer or gradient structure.Enumerated embodiment 70. The method according to any of enumerated embodiments 63 - 69, wherein the modification layer includes a silicon oxide, silicon nitride, or silicon oxynitride.Enumerated embodiment 71. The method according to any of enumerated embodiments 63 - 70, wherein the modification layer includes a silicate.Enumerated embodiment 72. The method according to any of enumerated embodiments 63 - 71, wherein the modification layer includes a metal oxide.Enumerated embodiment 73. The method according to any of enumerated embodiments 63 - 72, wherein the modification layer includes titania, alumina, zirconia, zinc oxide, or nickel oxide.Enumerated embodiment 74. The method according to any of enumerated embodiments 63 - 73, wherein the modification layer comprises a metal nitride or metal oxynitride, optionally wherein the metal of the metal nitride or metal oxynitride includes aluminum, titanium, vanadium, zirconium, hafnium, zinc, nickel, or tin, or a combination thereof.Enumerated embodiment 75. The method according to any of enumerated embodiments 63 - 74, wherein the modification layer includes titanicone, alucone, zircone, or zincone.Enumerated embodiment 76. The method according to any of enumerated embodiments 63 - 75, wherein the modification layer includes lithium phosphate, lithium aluminum oxide, LixSiyAhCh. or lithium phosphorus oxynitride (LiPON).Enumerated embodiment 77. The method according to any of enumerated embodiments 63 - 76, wherein the treating includes an additive process.Enumerated embodiment 78. The method according to any of enumerated embodiments 63 - 77, wherein the treating includes a transformative process.Enumerated embodiment 79. The method according to any of enumerated embodiments 63 - 78, wherein the includes a subtractive process.Enumerated embodiment 80. The method according to any of enumerated embodiments 63 - 79, wherein depositing the silicon-containing porous lithium storage layer includes PECVD.Enumerated embodiment 81. A method of making an anode for lithium-ion battery cell, the method including: depositing a silicon-containing porous lithium storage layer onto a current collector by a PVD or CVD process, wherein the lithium storage layer includes discontinuitiesdefining a plurality of lithium storage layer segments each having an upper surface and a sidewall; and treating the upper surface and at least some of the sidewall with a treatment plasma including a plasma treatment gas that does not include a silicon precursor gas.Enumerated embodiment 81. The cell according to any of enumerated embodiments 1 to 31, wherein spaces between the plurality of lithium storage layer segments are 0.01 - 5%, 5 - 10%, 10 - 15%. 15 - 20%, 20 - 25%. 25 - 30%, 30 - 35%, 35 - 40% of the anode surface area, or any combination of ranges thereof.Enumerated embodiment 82. The cell according to any of enumerated embodiments 1 to 31 and 81, wherein the plurality of lithium storage layer segments defines spacings in a 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 nm - 1 pm, 1 - 2 pm, 2 - 3 pm, 3 - 5 pm, 5 - 7 pm, 7 - 10 pm, 10 - 12 pm, 12 - 15 pm, 15 - 20 pm, or any combination of ranges thereof.

[0114] The specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of the invention. However, other embodiments of the invention may be directed to specific embodiments relating to each individual aspect, or specific combinations of these individual aspects.

[0115] The above description of example embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above.

[0116] In the preceding description, for the purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. It will be apparent to one skilled in the art. however, that certain embodiments may be practiced without some of these details, or with additional details.

[0117] Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present invention. Additionally, details of any specific embodiment may not always be present in variations of that embodiment or may be added to other embodiments.

[0118] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0119] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a method” includes a plurality of such methods and reference to “the anode” includes reference to one or more anodes and equivalents thereof know n to those skilled in the art, and so forth. The invention has now- been described in detail for the purposes of clarity’ and understanding. However, it will be appreciated that certain changes and modifications may be practiced within the scope of the appended claims.

[0120] All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes. None is admitted to be prior art.

Claims

We claim:

1. A lithium-ion battery cell comprising: an anode comprising a porous lithium storage layer disposed over an anode current collector and a modification layer provided on the lithium storage layer, wherein: i) the lithium storage layer comprises at least 40 atomic % silicon, tin, germanium, or a combination thereof; ii) the lithium storage layer includes discontinuities defining a plurality of lithium storage layer segments each having an upper surface and a sidewall; and iii) the modification layer is disposed on the upper surface and at least partially along the sidewall; a cathode comprising a cathode active material layer in electrical contact with a cathode current collector; and a lithium-ion-containing solid-state electrolyte (SSE) that is interposed between the lithium storage layer and the cathode active material layer.

2. The cell of claim 1, wherein the modification layer has a multilayer or gradient structure.

3. The cell of claim 1, wherein the modification layer comprises a silicon oxide, silicon nitride, or silicon oxynitride.

4. The cell of claim 1, wherein the modification layer comprises a silicate.

5. The cell of claim 1, wherein the modification layer comprises a metal oxide.

6. The cell of claim 1, wherein the modification layer comprises titania, alumina, zirconia, zinc oxide, or nickel oxide.

7. The cell of claim 1, wherein the modification layer comprises titanicone, alucone, zircone, or zincone.

8. The cell of claim 1, wherein the modification layer comprises lithium phosphate, lithium aluminum oxide, LixSiyAhCh, or lithium phosphorus oxynitride (UPON).

9. The cell of claim 1, wherein the modification layer is formed at least in part by exposure of lithium storage material to a plasma comprising or formed from a fluorinated or perfluorinated carbon-containing material.

10. The cell of claim 9, wherein the modification layer comprises a fluorine- containing compound.

11. The cell of claim 1, wherein the modification layer is configured to enhance lithium-ion conduction between the SSE and the lithium storage layer segments.

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

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

14. The cell of claim 13, wherein the ratio of nitrogen to silicon is in a range of 0.02 to 0.5.

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

16. The cell of claim 1, wherein surfaces of at least some internal pores of the lithium storage layer comprise an internal modification layer.

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

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

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

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

21. The cell of claim 1, wherein the SSE comprises a lithium argyrodite solid electrolyte, a lithium silicon sulfide solid electrolyte, or a lithium silicon sulfide halide solid electrolyte.

22. The cell of claim 1, wherein the cathode comprises a lithium metal oxide, wherein the metal includes cobalt, nickel, manganese, or any combination thereof.

23. The cell of claim 1, further comprising a compression system configured to apply a compressive force between the anode and cathode.

24. The cell of claim 1, wherein spaces between the plurality of lithium storage layer segments are 0.01% to 30% of the anode surface area.

25. The cell of claim 1, wherein the plurality of lithium storage layer segments defines spacings in a range of 0.2 nm to 5 pm.

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