Silicon anode multilayer body for an electrochemical cell

Abstract

In this specification, a negative electrode, i.e., an anode, for an electrochemical cell having two or more layers is provided. By each layer containing an anode active material having a different concentration, it is possible to provide an improvement in electrical and physical qualities with respect to a single-layer anode.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application is a related application of U.S. Patent Application No. 63 / 389,701, entitled "Silicon Anode Multilayer for Electrochemical Cells", filed on July 15, 2022, and claims priority under 35 U.S.C. § 119(e) to that patent application, the entire content of which is incorporated herein by reference for all purposes.

[0002] The various embodiments described herein relate to primary and secondary electrochemical cells containing solid electrolytes, the field of electrodes and electrode materials, and the corresponding methods for manufacturing and using them.

Background Art

[0003] Lithium - based rechargeable batteries are widely used for powering various modern forms of electronic devices and can serve as power sources for hybrid cars and fully electric vehicles. In conventional lithium - based rechargeable batteries, typically, carbon - based anodes are used for storing lithium ions. In these anodes, lithium ions are stored by intercalation between the planes of carbon atoms that make up the graphite particles. Carbon - based anodes have been customized to achieve acceptable performance in modern lithium - ion batteries. However, carbon - based anodes are approaching saturation in terms of their lithium - ion storage.

[0004] As an alternative to carbon - based anodes, alloy - type anodes can be mentioned. In alloy - type anodes, instead of intercalation between carbon sheets in graphite particles, alloying of lithium ions with the anode active material occurs. These materials can have a lithium - ion storage capacity up to 10 times (×10) greater than that of graphite anodes. Typical alloy - type anodes include silicon, tin, and aluminum, as well as more specialized materials such as germanium and gold. These alloy materials have their own advantages and disadvantages, such as cost, specific capacity, processability, and voltage penalty.

[0005] One of the problems to be addressed in such systems is the volume change associated with the alloying of lithium and the active material. For example, depending on the system, a volume change of nearly 400% can occur. The volume change can cause difficulties at the macro and micro levels. At the macro level, there may be a need to accommodate swollen cells in the battery pack, and at the micro level, crack formation may occur due to the continuous expansion and contraction of the active region. In that case, the particles within the active region may lose their electrical connection with the surrounding matrix, and there may also be an undesirable side reaction between the new surface of the particles and the battery electrolyte.

[0006] Silicon (Si) is an example of an alloy-type anode material, which theoretically can store more than 10 times the amount of lithium ions than graphite, has a moderate voltage penalty, and is abundant and inexpensive in bulk form. Unfortunately, in conventional liquid electrolyte lithium-ion cells, the large volume change of the silicon-lithium alloy (e.g., 400%) has hindered the efforts to adopt silicon for the anode. Crack formation occurs during the expansion and contraction of the material, and the newly exposed crack surface reacts to form a new solid electrolyte interphase, which consumes the electrolyte and the lithium supply in the cell. Therefore, the cell may lose a part of its capacity during each cycle and may ultimately lose its function after a few cycles.

[0007] There are not many solutions to solve the problem of volume expansion. The most common solution is simply to reduce the amount of active material in the anode, as a result, the volume expansion and contraction are reduced. However, this also leads to a decrease in the performance of the electrochemical cell, such as a reduction in the capacity of the cell. Liquid electrolytes have also been used to maintain the contact between the anode and the electrolyte, but solid electrolytes are generally safer and have higher thermal stability than liquid electrolytes. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] There is a need for an anode that provides improved cell performance and maintains interfacial contact with the electrolyte layer.

Means for Solving the Problem

[0009] In this specification, an anode assembly is provided. This assembly includes a first anode layer, and the first anode layer is operably in contact with a second anode layer. The first anode layer and the second anode layer each include an anode active material, a binder, a conductive additive, and optionally a solid electrolyte material. In some embodiments, the second anode layer includes a solid electrolyte material. The weight percentages of the anode active material, binder, conductive additive, and / or solid electrolyte material in the first anode layer are different from the amounts in the second anode layer. In an exemplary embodiment, the first anode layer is in direct contact with the second anode layer.

[0010] In some embodiments, the anode active material is present in the first anode layer in an amount of about 50 wt% or more of the first anode layer. In some embodiments, the anode active material is present in the second anode layer in an amount of about 20 wt% to about 70 wt% of the second anode layer.

[0011] In some embodiments, the anode active material of the first anode layer is an inorganic material. In some aspects, the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof. In an exemplary embodiment, the inorganic material is silicon, a silicon alloy, or a combination thereof. In a further exemplary embodiment, the silicon or silicon alloy has a particle size of less than about 1 micrometer.

[0012] In some embodiments, the anode active material of the second anode layer is an inorganic material. In some aspects, the inorganic material is selected from the group consisting of silicon, silicon alloy, tin, tin alloy, germanium, germanium alloy, and combinations thereof. In an exemplary embodiment, the inorganic material is silicon, silicon alloy, or a combination thereof. In a further exemplary embodiment, the silicon or silicon alloy has a particle size of about 1 micrometer. In yet a further exemplary embodiment, the anode active material in the first anode layer is the same as the anode active material in the second anode layer. In yet a further exemplary embodiment, the anode active material in the first anode layer is different from the anode active material in the second anode layer.

[0013] In some embodiments, the conductive additive of the first anode layer includes a carbon-based conductive additive. In some aspects, the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0014] In some embodiments, the conductive additive of the second anode layer includes a carbon-based conductive additive. In some aspects, the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0015] In some embodiments, the second anode layer further includes a tackifier. In some aspects, the tackifier includes a hydrocarbon resin.

[0016] In some embodiments, the second layer further includes a plasticizer. In some aspects, the plasticizer is dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

[0017] In some embodiments, the solid electrolyte material of the first layer is a sulfide electrolyte, an oxide electrolyte, an oxysulfide electrolyte, or a halide electrolyte. In some aspects, the particle size of the solid electrolyte material of the first layer is about 1 micrometer. In some embodiments, the first anode layer substantially does not contain the solid electrolyte material, for example, it contains no more than about 5 wt% of the first anode layer, or no more than about 1 wt% of the first anode layer. In some aspects, the first anode layer may be lacking in the solid electrolyte material.

[0018] In some embodiments, the solid electrolyte material of the second layer is a sulfide electrolyte, an oxide electrolyte, an oxysulfide electrolyte, or a halide electrolyte. In some aspects, the particle size of the solid electrolyte material of the second layer is about 1 micrometer.

[0019] In some embodiments, the first anode layer has a thickness of about 70 micrometers before densification. In some additional embodiments, the second anode layer has a thickness of about 50 micrometers before densification. In some aspects, the first anode layer has a thickness that is about 40% greater than the thickness of the second anode layer.

[0020] In some embodiments, a stack pressure of about 1500 psi or less is applied to the assembly. In some embodiments, the first anode layer includes vertical cracks. In an exemplary embodiment, the first anode layer includes vertical cracks as shown in FIG. 2. In some embodiments, the first anode layer includes vertical cracks, while the second anode layer does not include vertical cracks. In some exemplary embodiments, the second anode layer does not exhibit crack formation after the first cell cycle.

[0021] In some embodiments, the first anode layer has a porosity of about 25% to about 50%. In some additional embodiments, the second anode layer has a porosity of about 10% to about 50%.

[0022] In some preferred embodiments, the anode active material contains silicon in an amount of about 50 wt% to 98 wt% of the first anode layer, and the anode active material contains silicon in an amount of about 20 wt% to about 50 wt% of the second anode layer. In some embodiments, the anode active material contains silicon in an amount of about 50 wt% to about 70 wt% of the first anode layer, or more preferably in an amount of about 60 wt% to about 70 wt% of the first anode layer. In yet further embodiments, the anode active material contains silicon in an amount of about 20 wt% to about 40 wt% of the second anode layer, or more preferably in an amount of about 30 wt% of the second anode layer.

[0023] In some embodiments, the assembly is in contact with a current collector. In some embodiments, the assembly is in contact with a separator layer.

[0024] In some embodiments, the assembly includes a third anode layer. The third anode layer includes an anode active material, a binder, a conductive additive, and a solid electrolyte material. The amounts of the anode active material, binder, conductive additive, and / or solid electrolyte material in the third anode layer may be different from those in the first anode layer or the second anode layer.

[0025] Further provided herein is an assembly including a two-layer anode. The two-layer anode includes a first anode layer and a second anode layer. The first anode layer includes a first anode active material that is present in an amount of at least about 50 wt% of the first layer in the first layer, a first binder, a first conductive additive, and optionally a first solid electrolyte material. The second anode layer includes a second anode active material that is present in an amount of about 20 wt% to about 50 wt% of the second layer in the second layer, a second binder, a second conductive additive, and a second solid electrolyte material. In some exemplary embodiments, the first anode active material is the same as the second anode active material. In some additional exemplary embodiments, the first anode active material is different from the second anode active material.

[0026] In some embodiments, the first anode active material is an inorganic material. In some aspects, the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof. In a preferred embodiment, the inorganic material is silicon, a silicon alloy, or a combination thereof. In a more preferred embodiment, the silicon or silicon alloy has a particle size of less than about 1 micrometer.

[0027] In some embodiments, the second anode active material is an inorganic material. In some aspects, the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof. In a preferred embodiment, the inorganic material is silicon, a silicon alloy, or a combination thereof. In a further preferred embodiment, the silicon or silicon alloy has a particle size of about 1 micrometer.

[0028] In some embodiments, the first conductive additive includes a carbon-based conductive additive. In some aspects, the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0029] In some embodiments, the second conductive additive includes a carbon-based conductive additive. In some aspects, the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0030] In some embodiments, the second anode layer further includes a tackifier. In some aspects, the tackifier includes a hydrocarbon resin.

[0031] In some embodiments, the second anode layer further includes a plasticizer. In some aspects, the plasticizer is dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

[0032] In some embodiments, the first solid electrolyte material is a sulfide electrolyte, an oxide electrolyte, an oxysulfide electrolyte, or a halide electrolyte. In some aspects, the particle size of the first solid electrolyte material is about 1 micrometer. In some embodiments, the second solid electrolyte material is a sulfide electrolyte, an oxide electrolyte, an oxysulfide electrolyte, or a halide electrolyte. In some aspects, the particle size of the second solid electrolyte material is about 1 micrometer. In some embodiments, the first anode layer substantially does not include a solid electrolyte material, for example, it contains no more than about 5 wt% of the first anode layer, or no more than about 1 wt% of the first anode layer. In some aspects, the first anode layer may be lacking in the solid electrolyte material.

[0033] In some embodiments, the first anode layer has a thickness of about 70 micrometers before densification. In some embodiments, the second anode layer has a thickness of about 50 micrometers before densification. In an exemplary embodiment, the first anode layer has a thickness that is about 40% greater than the thickness of the second anode layer.

[0034] In some embodiments, a stack pressure of about 1500 psi or less is applied to the assembly. In some embodiments, the second anode layer does not exhibit crack formation after the first cell cycle.

[0035] In some embodiments, the first anode layer has a porosity of about 25% to about 50%. In some embodiments, the second layer has a porosity of about 10% to about 50%.

[0036] In an exemplary embodiment, the first anode active material contains silicon in an amount of about 50 wt% to 98 wt% of the first anode layer, and the second anode active material contains silicon in an amount of about 20 wt% to about 50 wt% of the second anode layer. In a preferred embodiment, the first anode active material contains silicon in an amount of about 50 wt% to about 70 wt%, or more preferably about 60 wt% to about 70 wt% of the first anode layer. In a preferred embodiment, the second anode active material contains silicon in an amount of about 20 wt% to about 40 wt%, or more preferably about 30 wt% of the second layer.

[0037] In some embodiments, the anode bilayer is in contact with the current collector. In some embodiments, the anode bilayer is in contact with the separator layer.

[0038] In some embodiments, the first anode layer includes vertical cracks. In some further embodiments, the first anode layer includes vertical cracks, but the second anode layer does not include vertical cracks. In an exemplary embodiment, the first anode layer includes vertical cracks as shown in FIG. 2.

[0039] Furthermore, the present specification provides an anode structure. The solid anode structure includes a first anode layer and a second anode layer. The first anode layer includes an active material containing silicon in an amount of about 60 wt% or more of the first layer, a first binder in an amount of about 7 wt% or less of the first layer, a first conductive additive in an amount of about 5 wt% or less of the first layer, and a first solid electrolyte material in an amount of about 23 wt% or less of the first layer. The second layer includes a second anode active material containing silicon in an amount of about 30 wt% of the second layer, a second binder in an amount of about 6 wt% of the second layer, a second conductive additive in an amount of about 5 wt% of the second layer, a second solid electrolyte material in an amount of about 45 wt% or less of the second layer, a plasticizer in an amount of about 4 wt% of the second layer, and a tackifier in an amount of about 10 wt% of the second layer.

[0040] Furthermore, the present specification provides an anode structure. The solid anode structure includes a first anode layer and a second anode layer. The first anode layer includes an active material containing silicon in an amount of about 60 wt% or more of the first layer, a first binder in an amount of about 7 wt% or less of the first layer, a first conductive additive in an amount of about 5 wt% or less of the first layer, and a first solid electrolyte material in an amount of about 23 wt% or less of the first layer. The second layer includes a second anode active material containing silicon in an amount of about 30 wt% of the second layer, a second binder in an amount of about 6 wt% of the second layer, a second conductive additive in an amount of about 5 wt% of the second layer, a second solid electrolyte material in an amount of about 45 wt% or less of the second layer, a plasticizer in an amount of about 4 wt% of the second layer, and a tackifier in an amount of about 10 wt% of the second layer.

[0041] Further, the present specification provides an anode assembly. The anode assembly includes a first anode layer and a second anode layer. The first anode layer includes an anode active material in an amount of about 60 wt% or more of the first layer, a first binder in an amount of about 0 wt% to about 20 wt% of the first layer, and a first solid electrolyte material in an amount of about 20 wt% to about 30 wt% of the first layer. The second layer includes a second anode active material in an amount of about 20 wt% to about 70 wt% of the second layer, a second binder in an amount of about 10 wt% or less of the second layer, and a second solid electrolyte material in an amount of about 45 wt% or less of the second layer.

[0042] Further, the present specification provides an electrochemical cell including the two-layer anode of the present disclosure, a separator layer, and a cathode layer. The electrolyte within the layers of the electrochemical cell may be solid, semi-solid (e.g., gel), and / or liquid. In certain embodiments, the anode layer may be a solid anode layer.

[0043] In some embodiments, the electrochemical cell further includes a first current collector disposed adjacent to the two-layer anode. In some aspects, the first current collector includes copper, nickel, or stainless steel.

[0044] In some embodiments, the electrochemical cell has a higher specific discharge capacity compared to an electrochemical cell with a single-layer anode. In some embodiments, the discharge capacity of the cell is stable over a greater number of cycles compared to an electrochemical cell with a single-layer anode. In an exemplary embodiment, the discharge capacity of the cell is stable for at least 100 cycles.

[0045] In some embodiments, the electrochemical cell has a lower internal resistance compared to an electrochemical cell with a single-layer anode.

[0046] In some embodiments, when the electrochemical cell is cycled at a stack pressure of less than 1500 psi, the bilayer anode does not separate from the separator layer.

[0047] In some embodiments, the bilayer anode has better surface contact with the separator layer compared to an electrochemical cell comprising a monolayer anode. In some embodiments, the surface contact between the bilayer anode and the separator layer is determined by SEM imaging. In some embodiments, there is less void space present between the bilayer anode and the separator layer compared to an electrochemical cell comprising a monolayer anode.

[0048] Further provided herein is a method of manufacturing a bilayer anode structure. The method includes: a) mixing an anode active material, at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one tackifier, optionally at least one plasticizer, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate; d) casting the second anode layer slurry onto the first anode layer slurry; and e) drying the first anode layer slurry and the second anode layer slurry to form an anode bilayer.

[0049] Furthermore, the present specification provides a method for manufacturing a two-layer anode structure. The method includes: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode layer slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one tackifier, optionally at least one plasticizer, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate and drying the first anode layer slurry; and d) casting the second anode layer slurry onto the first anode layer slurry and drying the second anode layer slurry.

[0050] Furthermore, the present specification provides an electrochemical cell including the two-layer anode of the present disclosure, a separator layer, and a cathode layer.

Brief Description of the Drawings

[0051] The present disclosure can be understood by referring to the following detailed description in conjunction with the drawings briefly described below. Note that for clarity of explanation, certain elements in the drawings may not be illustrated to scale.

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Mode for Carrying Out the Invention

[0052] In the following description, specific details are provided to give a complete understanding of various embodiments of the present disclosure. Reading and understanding this specification, the claims, and the drawings, those skilled in the art will understand that among the embodiments, there are some that can be implemented without adhering to some of the specific details described herein. Further, to avoid making the present disclosure unclear, some of the well-known methods, processes, devices, and systems used in various embodiments described herein are not disclosed in detail.

[0053] In this specification, an anode bilayer including a first anode layer is provided, where the first anode layer is operably in contact with a second anode layer. The first anode layer and the second anode layer each independently include an anode active material, a binder, a conductive additive, and optionally a solid electrolyte material. The amounts of the anode active material, binder, conductive additive, and / or solid electrolyte material in the first anode layer are different from the amounts of the anode active material, binder, conductive additive, and / or solid electrolyte material in the second anode layer.

[0054] Also in this specification, a structure including an anode bilayer including a first layer and a second layer is provided. The first layer includes a first anode active material, a first binder, a first conductive additive, and optionally a first solid electrolyte material. The first anode active material is present in the first layer in an amount of about 50% by weight or more of the first layer. The second layer includes a second anode active material, a second binder, a second conductive additive, and a second solid electrolyte material. The second anode active material is present in the second layer in an amount of about 50% by weight or more of the second layer. The first anode active material and the second anode active material may be the same anode active material or different ones. The first binder and the second binder may be the same binder or different ones. The first conductive additive and the second conductive additive may be the same conductive additive or different ones. The first solid electrolyte material and the second electrolyte material may be the same solid electrolyte material or different ones.

[0055] Within the scope of the spirit of the present disclosure, the term "first anode active material" should be understood to be able to refer to a single anode active material or two or more anode active materials. That is, the notations "first" or "second" should not be construed as limiting the anode active material being referred to to a single species. Further, terms such as "the anode active material" or "anode active material" should be construed to also refer to the first anode active material and / or the second anode active material. Similarly, references to "the anode layer" should be construed to include references to the first anode layer and / or the second anode layer.

[0056] FIG. 1 shows an electrochemical cell provided with the anode bilayer of the present disclosure. The first anode layer 100 can be in contact with the anode current collector 110. The second anode layer 102 can be in contact with the separator layer 104 (also referred to as the electrolyte layer). The first anode layer 100 and the second anode layer 102 can be in direct contact with each other. The separator layer 104 can be in contact with the cathode layer 106. The cathode layer 106 can be in contact with the cathode current collector 108.

[0057] Each anode layer contains an anode active material. The anode active material is preferably an inorganic material. The anode active material can include one or more inorganic materials, for example, silicon (Si), silicon alloy (e.g., Li x Si), tin (Sn), tin alloy, germanium (Ge), germanium alloy, graphite, Li4Ti5O 12 (LTO), or other known anode active materials, and combinations thereof. In a preferred embodiment, the anode active material contains silicon.

[0058] The silicon or silicon alloy in the first anode layer can have an average particle size of less than about 1 micrometer. As used herein, "silicon" refers to silicon metal or its alloy unless otherwise specified. The average particle size of silicon (i.e., D 50) can be described using methods well-known in the art. In some embodiments, the silicon can have an average particle size of less than 500 nm, less than 450 nm, less than 400 nm, less than 350 nm, less than 300 nm, less than 250 nm, less than 200 nm, less than 150 nm, or less than 100 nm. In some examples, the silicon has an average particle size of about 100 nm. In an exemplary embodiment, the silicon has an average particle size of about 50 nm to about 150 nm. In some additional embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 100 nm, about 100 nm to about 150 nm, about 150 nm to about 200 nm, about 200 nm to about 300 nm, about 300 nm to about 400 nm, about 400 nm to about 500 nm, about 500 nm to about 600 nm, about 600 nm to about 700 nm, about 700 nm to about 800 nm, about 800 nm to about 900 nm, or about 900 nm to about 1000 nm. In still further embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 150 nm, about 50 nm to about 200 nm, about 50 nm to about 300 nm, about 50 nm to about 400 nm, about 50 nm to about 500 nm, about 50 nm to about 600 nm, about 50 nm to about 700 nm, about 50 nm to about 800 nm, about 50 nm to about 900 nm, or about 50 nm to about 1000 nm.

[0059] The silicon or silicon alloy in the first anode layer can have an average particle size of about 1 micrometer. In some embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 100 nm, about 100 nm to about 150 nm, about 150 nm to about 200 nm, about 200 nm to about 300 nm, about 300 nm to about 400 nm, about 400 nm to about 500 nm, about 500 nm to about 600 nm, about 600 nm to about 700 nm, about 700 nm to about 800 nm, about 800 nm to about 900 nm, about 900 nm to about 1 micrometer, about 1 micrometer to about 2 micrometers, about 2 micrometers to about 3 micrometers, about 3 micrometers to about 4 micrometers, or about 4 micrometers to about 5 micrometers. Still further, in some embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 150 nm, about 50 nm to about 200 nm, about 50 nm to about 300 nm, about 50 nm to about 400 nm, about 50 nm to about 500 nm, about 50 nm to about 600 nm, about 50 nm to about 700 nm, about 50 nm to about 800 nm, about 50 nm to about 900 nm, about 50 nm to about 1 micrometer, about 50 nm to about 2 micrometers, about 50 nm to about 3 micrometers, about 50 nm to about 4 micrometers, about 50 nm to about 5 micrometers, about 100 nm to about 5 micrometers, about 150 nm to about 5 micrometers, about 200 nm to about 5 micrometers, about 300 nm to about 5 micrometers, about 400 nm to about 5 micrometers, about 500 nm to about 5 micrometers, about 600 nm to about 5 micrometers, about 700 nm to about 5 micrometers, about 800 nm to about 5 micrometers, about 900 nm to about 5 micrometers, about 1 micrometer to about 5 micrometers, about 2 micrometers to about 5 micrometers, or about 3 micrometers to about 5 micrometers.

[0060] The silicon or silicon alloy in the second anode layer can have an average particle size of less than about 1 micrometer. The average particle size of silicon (i.e., D 50) can be described using methods well known in the art. In some embodiments, the silicon can have an average particle size of less than 500 nm, less than 450 nm, less than 400 nm, less than 350 nm, less than 300 nm, less than 250 nm, less than 200 nm, less than 150 nm, or less than 100 nm. In some examples, the silicon has an average particle size of about 100 nm. In an exemplary embodiment, the silicon has an average particle size of about 50 nm to about 150 nm. In some additional embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 100 nm, about 100 nm to about 150 nm, about 150 nm to about 200 nm, about 200 nm to about 300 nm, about 300 nm to about 400 nm, about 400 nm to about 500 nm, about 500 nm to about 600 nm, about 600 nm to about 700 nm, about 700 nm to about 800 nm, about 800 nm to about 900 nm, or about 900 nm to about 1000 nm. In still further embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 150 nm, about 50 nm to about 200 nm, about 50 nm to about 300 nm, about 50 nm to about 400 nm, about 50 nm to about 500 nm, about 50 nm to about 600 nm, about 50 nm to about 700 nm, about 50 nm to about 800 nm, about 50 nm to about 900 nm, or about 50 nm to about 1000 nm.

[0061] The silicon or silicon alloy in the second anode layer can have an average particle size of about 1 micrometer. In some embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 100 nm, about 100 nm to about 150 nm, about 150 nm to about 200 nm, about 200 nm to about 300 nm, about 300 nm to about 400 nm, about 400 nm to about 500 nm, about 500 nm to about 600 nm, about 600 nm to about 700 nm, about 700 nm to about 800 nm, about 800 nm to about 900 nm, about 900 nm to about 1 micrometer, about 1 micrometer to about 2 micrometers, about 2 micrometers to about 3 micrometers, about 3 micrometers to about 4 micrometers, or about 4 micrometers to about 5 micrometers. In still further embodiments, the silicon or silicon alloy can have an average particle size of about 50 nm to about 150 nm, about 50 nm to about 200 nm, about 50 nm to about 300 nm, about 50 nm to about 400 nm, about 50 nm to about 500 nm, about 50 nm to about 600 nm, about 50 nm to about 700 nm, about 50 nm to about 800 nm, about 50 nm to about 900 nm, about 50 nm to about 1 micrometer, about 50 nm to about 2 micrometers, about 50 nm to about 3 micrometers, about 50 nm to about 4 micrometers, about 50 nm to about 5 micrometers, about 100 nm to about 5 micrometers, about 150 nm to about 5 micrometers, about 200 nm to about 5 micrometers, about 300 nm to about 5 micrometers, about 400 nm to about 5 micrometers, about 500 nm to about 5 micrometers, about 600 nm to about 5 micrometers, about 700 nm to about 5 micrometers, about 800 nm to about 5 micrometers, about 900 nm to about 5 micrometers, about 1 micrometer to about 5 micrometers, about 2 micrometers to about 5 micrometers, or about 3 micrometers to about 5 micrometers.

[0062] The anode active material can be present in an amount of about 40% by weight or more in the first anode layer. In some embodiments, the anode active material can be present in the first anode layer in an amount of about 35% to about 85% by weight, about 40% to about 85% by weight, about 40% to about 80% by weight, about 40% to about 75% by weight, about 40% to about 70% by weight, about 40% to about 65% by weight, about 40% to about 60% by weight, about 40% to about 55% by weight, or about 40% to about 50% by weight. In some additional embodiments, the anode active material can be present in the first anode layer in an amount of about 50% by weight or more. In some examples, the anode active material is present in the first anode layer in an amount of about 50% to about 60% by weight. In some additional embodiments, the anode active material can be present in the first anode layer in an amount of about 40% to about 50% by weight, about 50% to about 60% by weight, about 60% to about 70% by weight, about 70% to about 80% by weight, or about 80% to about 85% by weight.

[0063] The anode active material can be present in the second anode layer in an amount of about 20% to about 70% of the second anode layer. In some embodiments, the anode active material can be present in the second anode layer in an amount of about 20% to about 70% by weight, about 20% to about 65% by weight, about 20% to about 60% by weight, about 20% to about 55% by weight, about 20% to about 50% by weight, about 20% to about 45% by weight, about 20% to about 40% by weight, about 20% to about 35% by weight, about 20% to about 30% by weight, about 25% to about 50% by weight, about 25% to about 45% by weight, about 25% to about 40% by weight, about 25% to about 35% by weight, about 30% to about 50% by weight, about 30% to about 45% by weight, about 30% to about 40% by weight, about 35% to about 50% by weight, about 35% to about 45% by weight, or about 40% to about 50% by weight. In some additional embodiments, the anode active material can be present in the second anode layer in an amount of about 20% to about 25% by weight, about 25% to about 30% by weight, about 30% to about 35% by weight, about 35% to about 40% by weight, about 40% to about 45% by weight, or about 45% to about 50% by weight.

[0064] In some embodiments, the assembly includes a third anode layer. The third anode layer may be disposed adjacent to the second anode layer and, if a separator layer is present, may be disposed adjacent to the separator layer.

[0065] The anode active material can be present in the third anode layer in an amount of about 10 wt% to about 90 wt% of the third layer. The third anode layer may be disposed adjacent to the second anode layer and, if a separator layer is present, may be disposed adjacent to the separator layer. In some aspects, the anode active material is present in the third anode layer in an amount of about 10 wt% to about 20 wt%, about 10 wt% to about 30 wt%, about 10 wt% to about 40 wt%, about 10 wt% to about 50 wt%, about 10 wt% to about 60 wt%, about 10 wt% to about 70 wt%, about 10 wt% to about 80 wt%, about 20 wt% to about 90 wt%, about 30 wt% to about 90 wt%, about 40 wt% to about 90 wt%, about 50 wt% to about 90 wt%, about 60 wt% to about 90 wt%, about 70 wt% to about 90 wt%, or about 80 wt% to about 90 wt%.

[0066] In some embodiments, the assembly can further include a fourth anode layer, a fifth anode layer, a sixth anode layer, ··· or an nth layer.

[0067] In another embodiment, the anode active material in any anode layer, for example, the first anode layer, the second anode layer, the third anode layer ··· and the nth anode layer, can be present in an amount of about 5 wt% to about 99 wt% of the anode layer. For example, the anode active material can be present in an amount of about 5 wt% to about 10 wt%, about 5 wt% to about 20 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 50 wt%, about 5 wt% to about 60 wt%, about 5 wt% to about 70 wt%, about 5 wt% to about 80 wt%, about 5 wt% to about 90 wt%, about 5 wt% to about 95 wt%, about 10 wt% to about 99 wt%, about 20 wt% to about 99 wt%, about 30 wt% to about 99 wt%, about 40 wt% to about 99 wt%, about 50 wt% to about 99 wt%, about 60 wt% to about 99 wt%, about 70 wt% to about 99 wt%, about 80 wt% to about 99 wt%, about 90 wt% to about 99 wt%, or about 95 wt% to about 99 wt% in any anode layer. In other examples, the anode active material can be present in an amount of about 5 wt% to about 10 wt%, about 10 wt% to about 20 wt%, about 20 wt% to about 30 wt%, about 30 wt% to about 40 wt%, about 40 wt% to about 50 wt%, about 50 wt% to about 60 wt%, about 60 wt% to about 70 wt%, about 70 wt% to about 80 wt%, about 80 wt% to about 90 wt%, about 90 wt% to about 95 wt%, or about 95 wt% to about 99 wt% in any anode layer.

[0068] Generally, each anode layer contains a conductive additive. The conductive additive helps to evenly distribute the charge density throughout the anode. Examples of the conductive additive can include metal powders, fibers, filaments, or any other material known to conduct electrons. The conductive additive can include carbon-based conductive additives such as carbon fibers, graphite, graphene, carbon black, conductive carbon, amorphous carbon, vapor-grown carbon fibers (VGCF), carbon nanotubes, carbon nanowires, activated carbon, and combinations thereof.

[0069] In some embodiments, the conductive additive can be present in the anode layer in an amount of about 0 wt% to about 15 wt% of the anode layer. In some aspects, the conductive additive can be present in the anode layer in an amount of about 0 wt% to about 10 wt%, or about 0 wt% to about 5 wt% of the anode layer. In some additional aspects, the conductive additive can be present in the anode layer in an amount of about 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or about 15 wt% of the anode layer. In an exemplary embodiment, the conductive additive is present in the anode layer in an amount of about 0 wt% to about 5 wt% of the anode layer.

[0070] In some embodiments, the average particle size of the conductive additive can be from about 5 nm to about 100 nm. In some aspects, the average particle size of the conductive additive can be from about 5 nm to about 10 nm, from about 5 nm to about 20 nm, from about 5 nm to about 30 nm, from about 5 nm to about 40 nm, from about 5 nm to about 50 nm, from about 5 nm to about 60 nm, from about 5 nm to about 70 nm, from about 5 nm to about 80 nm, from about 5 nm to about 90 nm, from about 10 nm to about 100 nm, from about 20 nm to about 100 nm, from about 30 nm to about 100 nm, from about 40 nm to about 100 nm, from about 50 nm to about 100 nm, from about 60 nm to about 100 nm, from about 70 nm to about 100 nm, from about 80 nm to about 100 nm, from about 90 nm to about 100 nm, from about 10 nm to about 50 nm, or from about 20 nm to about 40 nm. In some examples, the conductive additive can have a particle size of about 30 nm.

[0071] In some additional embodiments, the average particle size of the conductive additive may be up to about 7 micrometers, including about 0.1 micrometer, about 0.5 micrometer, about 1 micrometer, about 1.5 micrometers, about 2 micrometers, about 2.5 micrometers, about 3 micrometers, about 3.5 micrometers, about 4 micrometers, about 4.5 micrometers, about 5 micrometers, about 5.5 micrometers, about 6 micrometers, about 6.5 micrometers, or about 7 micrometers. In one particular example, the conductive additive is graphite having an average particle size of about 6 micrometers.

[0072] Either one or both of the anode layers may contain a solid electrolyte material. The solid electrolyte material, together with the conductive additive, helps to uniformly distribute the charge density throughout the anode. One or more solid electrolyte materials can include oxides, oxysulfides, sulfides, halides, nitrides, or any other solid electrolytes known in the art. In some preferred embodiments, one or more solid electrolyte materials can include a sulfide solid electrolyte material, i.e., a solid electrolyte having at least one sulfur component. In some embodiments, one or more solid electrolytes can include a combination of one or more materials, e.g., Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2 S -P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-S-SiS2-LiCl, Li2S-S-SiS2-B2S3-LiI, Li2S-S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers and Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-S-SiS2-Li3PO4, and Li2S-S-SiS2-Li x MO y(Here, x and y are positive numbers, and M is P, Si, Ge, B, Al, Ga, or In) can be included. The halide solid electrolyte can have a structure Li-M-X, where M is a metal element and X is a halogen. These can be represented by the general formula Li α M 4+ β N 3+ (1-β) X Ω Y (6-Ω) where 0 ≦ β ≦ 1; 0 ≦ Ω ≦ 6; α = 6 - [(β * 4) + (1 - β) * 3]; X and Y are halogens, for example, F, Cl, Br, I; M is an element with an oxidation number of 4+, such as Ti, Zr, Hf, and Rf; N is an element with an oxidation number of 3+, such as Ga, In, and Tl, Sc, Y, Fe, Ru, Os, Er. Examples of halide electrolytes include Li2ZrCl6, Li3InCl6, Li 2.25 Hf 0.75 Fe 0.25 Cl4Br2.

[0073] In some embodiments, the first anode layer may not substantially contain a solid electrolyte material. Without wishing to be bound by theory, it is believed that by reducing the amount of solid electrolyte material in the first anode layer, corrosion in the current collector is reduced, especially when the current collector contains copper. As used herein, "substantially free of solid electrolyte" means that the solid electrolyte is present in an amount of about 5 wt% or less of the first anode layer in the first anode layer. For example, the solid electrolyte material that a first anode layer substantially free of solid electrolyte material may contain is 5 wt% or less, 4 wt% or less, 3 wt% or less, 2 wt% or less, 1 wt% or less, 0.5 wt% or less, 0.1 wt% or less, 0.05 wt% or less, or 0.01 wt% or less of the first anode layer. In some additional embodiments, the first anode layer may be lacking in solid electrolyte material.

[0074] In other embodiments, the anode layer can include a semi-solid electrolyte or a liquid electrolyte.

[0075] In another embodiment, the solid electrolyte material is one or more of Li3PS4, Li4P2S6, Li7P3S 11 , Li 10 GeP2S 12 , Li 10 SnP2S 12 . In a further embodiment, the solid electrolyte may be one or more of Li6PS5Cl, Li6PS5Br, Li6PS5I, and may also be represented by the formula Li 7-y PS 6-y X y , where "X" represents at least one halogen and / or at least one pseudohalogen, 0 < y ≦ 2.0, the halogen may be one or more of F, Cl, Br, I, and the pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN. In yet another embodiment, the solid electrolyte material is represented by the formula Li 8-y-z P2S 9-y-z X y W z (where "X" and "W" represent at least one halogen and / or at least one pseudohalogen, 0 ≦ y ≦ 1 and 0 ≦ z ≦ 1), the halogen may be one or more of F, Cl, Br, I, and the pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN).

[0076] In some embodiments, the solid electrolyte material can be present in the anode layer in an amount of about 0 wt% to about 70 wt% of the anode layer. For example, the solid electrolyte can be present in the anode layer in an amount of about 0 wt% to about 10 wt%, about 0 wt% to about 20 wt%, about 0 wt% to about 30 wt%, about 0 wt% to about 40 wt%, about 0 wt% to about 50 wt%, about 0 wt% to about 60 wt%, about 10 wt% to about 70 wt%, about 20 wt% to about 70 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 70 wt%, about 50 wt% to about 70 wt%, or about 60 wt% to about 70 wt%. In some embodiments, the solid electrolyte material can be present in the anode layer in an amount of about 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, or about 70 wt% of the anode layer. In a preferred embodiment, the solid electrolyte material is present in an amount of about 20 wt% to about 30 wt% of the anode layer.

[0077] In some additional embodiments, the solid electrolyte material can be present in the anode layer in an amount less than about 60 wt% of the anode layer. For example, the solid electrolyte can be present in the anode layer in an amount less than about 55 wt% of the anode layer, less than about 50 wt% of the anode layer, less than about 45 wt% of the anode layer, less than about 40 wt% of the anode layer, less than about 35 wt% of the anode layer, less than about 30 wt% of the anode layer, less than about 25 wt% of the anode layer, less than about 20 wt% of the anode layer, less than about 15 wt% of the anode layer, less than about 10 wt% of the anode layer, or less than about 5 wt% of the anode layer. In a preferred embodiment, the solid electrolyte material is present in an amount less than about 25 wt% of the anode layer.

[0078] The solid electrolyte material can have an average particle size of about 0.5 to about 2 micrometers. In some embodiments, the solid electrolyte material can have a particle size of about 0.5 micrometer to about 0.75 micrometer, about 0.75 micrometer to about 1 micrometer, about 1 micrometer to about 1.25 micrometer, about 1.25 micrometer to about 1.5 micrometer, about 1.5 micrometer to about 1.75 micrometer, or about 1.75 micrometer to about 2 micrometers. In a preferred embodiment, the solid electrolyte material has a particle size of about 1 micrometer.

[0079] Generally, the anode layer includes a binder. The binder aids in the adhesion of the first anode layer to the current collector and the adhesion of the second anode layer to the first anode layer and the separator layer. The binder also forms a flexible matrix when mixed with the solid electrolyte material. Further, the binder enables the suspension of the anode active material and the conductive additive in the electrolyte matrix, thereby enabling the electrode layer to maintain interparticle contact during the expansion and contraction of the anode active material.

[0080] In some embodiments, the binder can include a fluororesin having vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), and derivatives thereof as structural units. In some additional embodiments, the binder can include homopolymers such as polyvinylidene fluoride (PVdF), polyhexafluoropropylene (PHFP), and polytetrafluoroethylene (PTFE), and binary copolymers such as a copolymer of VdF and HFP, such as a poly(vinylidene fluoride - hexafluoropropylene) copolymer (PVdF - HFP). In another embodiment, the binder can be one or more of thermoplastic elastomers such as, but not limited to, styrene - butadiene rubber (SBR), styrene - butadiene - styrene block copolymer (SBS), styrene - isoprene block copolymer (SIS), styrene - ethylene - butylene - styrene block copolymer (SEBS), polyacrylonitrile (PAN), nitrile - butadiene rubber (NBR), polybutadiene, polyisoprene, poly(methacrylate) nitrile - butadiene rubber (PMMA - NBR). In other embodiments, examples of the binder can include cellulose - based binders such as carboxymethyl cellulose (CMC). In further embodiments, the binder can be one or more of styrene - based thermoplastic resins such as, but not limited to, styrene - butadiene rubber (SBR), styrene - butadiene - styrene block copolymer (SBS), styrene - isoprene block copolymer (SIS), polystyrene (PS), or styrene - ethylene - butylene - styrene block copolymer (SEBS). In other embodiments, the binder can include one or more of styrene - butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations or derivatives thereof.

[0081] In yet another embodiment, the binder may be one or more of acrylic resins such as, but not limited to, polymethyl (meth)acrylate, polyethyl (meth)acrylate, polyisopropyl (meth)acrylate, polyisobutyl (meth)acrylate, polybutyl (meth)acrylate, etc. In yet another embodiment, the binder may be one or more of polycondensates such as, but not limited to, polyurea, polyamide paper, polyimide, polyester, etc. In yet a further embodiment, the binder may be one or more of nitrile rubbers such as, but not limited to, acrylonitrile-butadiene rubber (ABR), polystyrene-nitrile-butadiene rubber (PS-NBR), and mixtures thereof.

[0082] In a preferred embodiment, the binder can include a styrene block copolymer or a styrenic thermoplastic resin. In some embodiments, the binder can be present in the anode layer in an amount of about 0% to about 20% by weight of the anode layer. For example, the binder can be present in the anode layer in an amount of about 0% to about 5%, about 0% to about 10%, about 0% to about 15%, about 5% to about 20%, about 10% to about 20%, or about 15% to about 20%. In an exemplary embodiment, the binder is present in the anode layer in an amount of about 4% to about 5% by weight.

[0083] The anode layer can contain a tackifier. The tackifier increases the tackiness of the anode layer, i.e., the rate of formation of the adhesive bond. Generally, examples of tackifiers include hydrocarbon resins such as hydrogenated aromatic resins, aromatic resins, terpene resins, modified terpene resins, aliphatic resins, alicyclic resins, hydrogenated hydrocarbon resins, and combinations thereof. Such resins and their methods of obtaining and manufacturing are generally known in the art. Preferably, the tackifier and the binder are miscible, i.e., have similar solubility parameters. Without wishing to be bound by theory, when the tackifier and the binder are miscible, this mixture has a lower modulus of elasticity and a higher glass transition temperature compared to immiscible binders and tackifiers. In a preferred embodiment, the tackifier is a hydrogenated aromatic resin. In a preferred embodiment, only the second anode layer contains a tackifier, i.e., there is no tackifier in the first anode layer.

[0084] The tackifier can have a softening point of about 20°C to about 150°C. The tackifier can have a molecular weight of about 300 g / mol to about 10,000 g / mol. The tackifier can have a density of about 0.75 kg / L to about 1.25 kg / L. The tackifier can have a glass transition temperature of about -30°C to about 150°C.

[0085] The tackifier can be present in an amount of about 0 wt% to about 15 wt% of the anode layer. In some embodiments, the tackifier can be present in an amount of about 0 wt% to about 5 wt% of the anode layer, about 0 wt% to about 10 wt% of the anode layer, about 5 wt% to about 10 wt% of the anode layer, or about 10 wt% to about 15 wt% of the anode layer. In an exemplary embodiment, the tackifier is present in an amount of about 10 wt% of the anode layer.

[0086] The anode layer can contain a plasticizer. The plasticizer increases the flexibility of the anode layer, thereby making it less likely for damage and crack formation to occur during volume expansion and contraction. Examples of plasticizers include phthalates, sebacates, adipates, and other esters. Examples of phthalates include dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dipentyl phthalate, dihexyl phthalate, diheptyl phthalate, dioctyl phthalate, dinonyl phthalate, didecyl phthalate, diundecyl phthalate, didodecyl phthalate, and other phthalates, as well as isomers or derivatives thereof. Examples of sebacates include dimethyl sebacate, diethyl sebacate, dipropyl sebacate, dibutyl sebacate, dipentyl sebacate, dihexyl sebacate, diheptyl sebacate, dioctyl sebacate, dinonyl sebacate, didecyl sebacate, diundecyl sebacate, didodecyl sebacate, and other sebacates, as well as isomers or derivatives thereof. Examples of adipates include dimethyl adipate, diethyl adipate, dipropyl adipate, dibutyl adipate, dipentyl adipate, dihexyl adipate, diheptyl adipate, dioctyl adipate, dinonyl adipate, didecyl adipate, diundecyl adipate, didodecyl adipate, and other adipates, as well as isomers or derivatives thereof. In certain embodiments, examples of plasticizers can include dioctyl phthalate, dibutyl sebacate, mineral oil, or other plasticizers known in the art, or combinations thereof. In a preferred embodiment, only the second anode layer contains a plasticizer, i.e., there is no plasticizer present in the first anode layer.

[0087] The plasticizer can be present in the anode layer in an amount of about 0 wt% to about 8 wt% of the anode layer. In some embodiments, the plasticizer can be present in the anode layer in an amount of about 0 wt% to about 2 wt%, about 0 wt% to about 4 wt%, about 0 wt% to about 6 wt%, about 2 wt% to about 4 wt%, about 2 wt% to about 6 wt%, about 2 wt% to about 8 wt%, about 4 wt% to about 6 wt%, about 4 wt% to about 8 wt%, or about 6 wt% to about 8 wt% of the anode layer. In an exemplary embodiment, the plasticizer is present in the anode layer in an amount of about 4 wt% of the anode layer.

[0088] The anode layer structure can be densified using densification methods known to those skilled in the art, such as calendering, linear pressing, and the like.

[0089] Before densification and before drying (i.e., removal of the solvent), the first anode layer can have a thickness of about 50 micrometers to about 100 micrometers. In some embodiments, the first anode layer can have a thickness of about 50 micrometers to about 60 micrometers, about 50 micrometers to about 70 micrometers, about 50 micrometers to about 80 micrometers, about 50 micrometers to about 90 micrometers, about 60 micrometers to about 70 micrometers, about 60 micrometers to about 80 micrometers, about 60 micrometers to about 90 micrometers, about 60 micrometers to about 100 micrometers, about 70 micrometers to about 80 micrometers, about 70 micrometers to about 90 micrometers, about 70 micrometers to about 100 micrometers, about 80 micrometers to about 90 micrometers, about 80 micrometers to about 100 micrometers, or about 90 micrometers to about 100 micrometers before densification and before drying. In a preferred embodiment, the structure can have a thickness of about 70 micrometers before densification and before drying.

[0090] Before densification and after drying, the first anode layer can have a thickness of from about 15 micrometers to about 50 micrometers. In some embodiments, the first anode layer can have a thickness of from about 15 micrometers to about 20 micrometers, from about 20 micrometers to about 30 micrometers, from about 30 micrometers to about 40 micrometers, from about 40 micrometers to about 50 micrometers, from about 15 micrometers to about 30 micrometers, from about 15 micrometers to about 40 micrometers, from about 20 micrometers to about 50 micrometers, from about 30 micrometers to about 50 micrometers, or from about 40 micrometers to about 50 micrometers before densification and after drying.

[0091] Before densification and before drying, the second anode layer can have a thickness of from about 20 micrometers to about 70 micrometers. In some embodiments, the second anode layer can have a thickness of from about 20 micrometers to about 30 micrometers, from about 20 micrometers to about 40 micrometers, from about 20 micrometers to about 50 micrometers, from about 20 micrometers to about 60 micrometers, from about 30 micrometers to about 40 micrometers, from about 30 micrometers to about 50 micrometers, from about 30 micrometers to about 60 micrometers, from about 30 micrometers to about 70 micrometers, from about 40 micrometers to about 50 micrometers, from about 40 micrometers to about 60 micrometers, from about 40 micrometers to about 70 micrometers, from about 50 micrometers to about 60 micrometers, from about 50 micrometers to about 70 micrometers, or from about 60 micrometers to about 70 micrometers before densification and before drying. In a preferred embodiment, the second anode layer can have a thickness of about 50 micrometers before densification and before drying.

[0092] Before densification and after drying, the first anode layer can have a thickness of from about 15 micrometers to about 50 micrometers. In some embodiments, the first anode layer can have a thickness of from about 15 micrometers to about 20 micrometers, from about 20 micrometers to about 30 micrometers, from about 30 micrometers to about 40 micrometers, from about 40 micrometers to about 50 micrometers, from about 15 micrometers to about 30 micrometers, from about 15 micrometers to about 40 micrometers, from about 20 micrometers to about 50 micrometers, from about 30 micrometers to about 50 micrometers, or from about 40 micrometers to about 50 micrometers before densification and after drying.

[0093] Generally, the thickness of the first anode layer can be made greater than the thickness of the second anode layer. In some embodiments, the thickness of the first anode layer can be about 10% greater than the thickness of the second anode layer, about 20% greater than the thickness of the second anode layer, about 30% greater than the thickness of the second anode layer, about 40% greater than the thickness of the second anode layer, about 50% greater than the thickness of the second anode layer, about 60% greater than the thickness of the second anode layer, or about 70% greater than the thickness of the second anode layer. In an exemplary embodiment, the thickness of the first anode layer is about 40% greater than the thickness of the second anode layer.

[0094] A stack pressure of about 3000 psi or less can be applied to the structure. In some embodiments, the stack pressure can be about 3000 psi or less, about 2500 psi or less, about 2000 psi or less, about 1500 psi or less, about 1000 psi or less, about 750 psi or less, about 500 psi or less, or about 250 psi or less. In an exemplary embodiment, a stack pressure of about 1500 psi or less is applied to the structure. In some additional embodiments, the stack pressure applied to the structure can be about 100 psi to about 250 psi, about 100 psi to about 500 psi, about 100 psi to about 750 psi, about 100 psi to about 1000 psi, about 100 psi to about 1500 psi, about 100 psi to about 2000 psi, about 100 psi to about 2500 psi, about 100 psi to about 3000 psi, about 250 psi to about 3000 psi, about 500 psi to about 3000 psi, about 750 psi to about 3000 psi, about 1000 psi to about 3000 psi, about 1500 psi to about 3000 psi, about 2000 psi to about 3000 psi, about 2500 psi to about 3000 psi, about 250 psi to about 2500 psi, about 750 psi to about 2000 psi, or about 1000 psi to about 2000 psi.

[0095] After an initial cell cycle or a series of conditioning cycles, the assembly may form vertical cracks. As used herein, a "vertical" crack refers to a crack that is substantially perpendicular to the interface between the anode and an adjacent anode current collector and has little or no branching within the crack. In some embodiments, the crack can be positioned at an angle of 90° ± about 25° with respect to the anode current collector. For example, the crack can be positioned at an angle of about 65° to about 115°, about 70° to about 110°, about 80° to about 100°, about 85° to about 95°, about 80° to about 90°, about 85° to about 90°, about 90° to about 100°, or about 90° to about 95°. In some additional examples, the crack can be positioned at an angle of about 65°, about 66°, about 67°, about 68°, about 69°, about 70°, about 71°, about 72°, about 73°, about 74°, about 75°, about 76°, about 77°, about 78°, about 79°, about 80°, about 81°, about 82°, about 83°, about 84°, about 85°, about 86°, about 87°, about 88°, about 89°, about 90°, about 91°, about 92°, about 93°, about 94°, about 95°, about 96°, about 97°, about 98°, about 99°, about 100°, about 101°, about 102°, about 103°, about 104°, about 105°, about 106°, about 107°, about 108°, about 109°, about 110°, about 111°, about 112°, about 113°, about 114°, or about 115° with respect to the anode current collector. In some additional embodiments, the crack may be orthogonal to the anode current collector.

[0096] Figure 2 shows an electrochemical cell comprising the anode bilayer of the present disclosure. The first anode layer 100 includes a plurality of vertical cracks 112. The cracks can occur during the initial cell cycle of the electrochemical cell or during a series of conditioning cycles.

[0097] The first anode layer can include vertical cracks. In an exemplary embodiment, the first anode layer can have cracks as shown in Figure 2. The second anode layer can include vertical cracks.

[0098] In some examples, the second anode layer can have cracks that are smaller and / or less prominent than those of the first anode layer. In some examples, the second anode layer may not have cracks.

[0099] The first anode layer can have a density of about 1.0 g / cm 3 ~ about 2.0 g / cm 3 In some embodiments, the first anode layer is about 1.0 g / cm 3~ about 1.1 g / cm 3 about 1.1 g / cm 3 ~ about 1.2 g / cm 3 about 1.2 g / cm 3 ~ about 1.3 g / cm 3 about 1.3 g / cm 3 ~ about 1.4 g / cm 3 about 1.4 g / cm 3 ~ about 1.5 g / cm 3 about 1.5 g / cm 3 ~ about 1.6 g / cm 3 about 1.6 g / cm 3 ~ about 1.7 g / cm 3 about 1.7 g / cm 3 ~ about 1.8 g / cm 3 about 1.8 g / cm 3 ~ about 1.9 g / cm 3 about 1.9 g / cm 3 ~ about 2.0 g / cm 3 about 1.0 g / cm 3 ~ about 1.2 g / cm 3 about 1.0 g / cm 3 ~ about 1.3 g / cm 3 about 1.0 g / cm 3 ~ about 1.4 g / cm 3 about 1.0 g / cm 3~ about 1.5 g / cm 3 about 1.0 g / cm 3 ~ about 1.6 g / cm 3 about 1.0 g / cm 3 ~ about 1.7 g / cm 3 about 1.0 g / cm 3 ~ about 1.8 g / cm 3 about 1.0 g / cm 3~about 1.9 g / cm 3 、about 1.1 g / cm 3 ~about 2.0 g / cm 3 、about 1.2 g / cm 3 ~about 2.0 g / cm 3 、about 1.3 g / cm 3 ~about 2.0 g / cm 3 、about 1.4 g / cm 3 ~about 2.0 g / cm 3 、about 1.5 g / cm 3 ~about 2.0 g / cm 3 、about 1.6 g / cm 3 ~about 2.0 g / cm 3 、about 1.7 g / cm 3 ~about 2.0 g / cm 3 、about 1.8 g / cm 3 ~about 2.0 g / cm 3 、or about 1.9 g / cm 3 ~about 2.0 g / cm 3 and can have a density of.

[0100] The density of the second anode layer may be the same as or higher than the density of the first anode layer. The second anode layer can have a density of about 1.0 g / cm 3 ~about 2.0 g / cm 3 In some embodiments, the second anode layer has a density of about 1.0 g / cm 3~ about 1.1 g / cm 3 、about 1.1 g / cm 3 ~about 1.2 g / cm 3 、about 1.2 g / cm 3 ~about 1.3 g / cm 3 、about 1.3 g / cm 3 ~about 1.4 g / cm 3 、about 1.4 g / cm 3 ~about 1.5 g / cm 3 、about 1.5 g / cm 3 ~about 1.6 g / cm 3 、about 1.6 g / cm 3 ~about 1.7 g / cm 3 、about 1.7 g / cm 3 ~about 1.8 g / cm 3 、about 1.8 g / cm 3 ~about 1.9 g / cm3 , about 1.9 g / cm 3 to about 2.0 g / cm 3 , about 1.0 g / cm 3 to about 1.2 g / cm 3 , about 1.0 g / cm 3 to about 1.3 g / cm 3 , about 1.0 g / cm 3 to about 1.4 g / cm 3 , about 1.0 g / cm 3~ about 1.5 g / cm 3 , about 1.0 g / cm 3 to about 1.6 g / cm 3 , about 1.0 g / cm 3 to about 1.7 g / cm 3 , about 1.0 g / cm 3 to about 1.8 g / cm 3 , about 1.0 g / cm 3 to about 1.9 g / cm 3 , about 1.1 g / cm 3 to about 2.0 g / cm 3 , about 1.2 g / cm 3 to about 2.0 g / cm 3 , about 1.3 g / cm 3 to about 2.0 g / cm 3 , about 1.4 g / cm 3 to about 2.0 g / cm 3 , about 1.5 g / cm 3 to about 2.0 g / cm 3 , about 1.6 g / cm 3 to about 2.0 g / cm 3 , about 1.7 g / cm 3 to about 2.0 g / cm 3 , about 1.8 g / cm 3 to about 2.0 g / cm 3 , or about 1.9 g / cm 3 to about 2.0 g / cm 3 and can have a density of.

[0101] Any other anode layer (e.g., the third anode layer, the fourth anode layer, etc.) can have a density of about 1.0 g / cm 3 to about 2.0 g / cm 3 and can have a density of. In some embodiments, the anode layer is about 1.0 g / cm 3~Approximately 1.1 g / cm 3 、 approximately 1.1 g / cm 3 ~ approximately 1.2 g / cm 3 、 approximately 1.2 g / cm 3 ~ approximately 1.3 g / cm 3 、 approximately 1.3 g / cm 3 ~ approximately 1.4 g / cm 3 、 approximately 1.4 g / cm 3 ~ approximately 1.5 g / cm 3 、 approximately 1.5 g / cm 3 ~ approximately 1.6 g / cm 3 、 approximately 1.6 g / cm 3 ~ approximately 1.7 g / cm 3 、 approximately 1.7 g / cm 3 ~ approximately 1.8 g / cm 3 、 approximately 1.8 g / cm 3 ~ approximately 1.9 g / cm 3 、 approximately 1.9 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.2 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.3 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.4 g / cm 3 、 approximately 1.0 g / cm 3~ approximately 1.5 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.6 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.7 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.8 g / cm 3 、 approximately 1.0 g / cm 3 ~ approximately 1.9 g / cm 3 、 approximately 1.1 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.2 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.3 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.4 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.5 g / cm 3 ~ approximately 2.0 g / cm 3 、 approximately 1.6 g / cm3 ~ about 2.0 g / cm 3 、 about 1.7 g / cm 3 ~ about 2.0 g / cm 3 、 about 1.8 g / cm 3 ~ about 2.0 g / cm 3 、 or about 1.9 g / cm 3 ~ about 2.0 g / cm 3 and can have a density of.

[0102] The first anode layer can have a porosity of about 25% to about 50%. Methods for measuring porosity are generally known in the art. In some embodiments, the first anode layer is about 25% to about 30%, about 25% to about 35%, about 25% to about 40%, about 25% to about 45%, about 30% to about 35%, about 30% to about 40%, about 30% to about 45%, about 30% to about 50%, about 35% to about 40%, about 35% to about 45%, about 35% to about 50%, about 40% to about 45%, about 40% to about 50%, or about 45% to about 50% porosity. In an exemplary embodiment, the first anode layer has a porosity of about 40%.

[0103] The second anode layer can have a porosity of from about 10% to about 50%. Generally, the second anode layer has a lower porosity than the first anode layer because there is less expansion and contraction in the second anode layer. In some embodiments, the second anode layer has a porosity of about 10% to about 15%, about 10% to about 20%, about 10% to about 25%, about 10% to about 30%, about 10% to about 35%, about 10% to about 40%, about 10% to about 45%, about 15% to about 20%, about 15% to about 25%, about 15% to about 30%, about 15% to about 35%, about 15% to about 40%, about 15% to about 45%, about 15% to about 50%, about 20% to about 25%, about 20% to about 30%, about 20% to about 35%, about 20% to about 40%, about 20% to about 45%, about 20% to about 50%, about 25% to about 30%, about 25% to about 35%, about 25% to about 40%, about 25% to about 45%, about 30% to about 35%, about 30% to about 40%, about 30% to about 45%, about 30% to about 50%, about 35% to about 40%, about 35% to about 45%, about 35% to about 50%, about 40% to about 45%, about 40% to about 50%, or about 45% to about 50%.

[0104] The anode layer may be a solid anode layer.

[0105] In the exemplary electrochemical cell shown in FIG. 1, the first anode layer 100 includes silicon in an amount of about 60 wt%, a styrenic thermoplastic resin in an amount of about 7 wt%, a carbon-based conductive additive in an amount of about 5 wt%, and a sulfide solid electrolyte in an amount of about 28 wt%. The second anode layer 102 includes silicon in an amount of about 30 wt%, a carbon-based conductive additive in an amount of about 5 wt%, a styrenic thermoplastic resin in an amount of about 7 wt%, and a sulfide solid electrolyte in an amount of about 58 wt%.

[0106] In the exemplary electrochemical cell shown in FIG. 2, the first anode layer 100 includes silicon in an amount of about 60% by weight, a styrenic thermoplastic resin in an amount of about 7% by weight, and a solid electrolyte in an amount of about 33% by weight. The second anode layer 102 includes silicon in an amount of about 30% by weight, a carbon-based conductive additive in an amount of about 5% by weight, a sulfide solid electrolyte material in an amount of about 45% by weight, and a total amount of about 20% by weight of a styrenic thermoplastic resin, a plasticizer, and a tackifier.

[0107] Furthermore, provided herein is an electrochemical cell comprising the anode bilayer structure of the present disclosure. Referring to FIG. 1, the electrochemical cell includes an anode bilayer of the present disclosure, the anode bilayer including a first anode layer 100 and a second anode layer 102, a separator layer 104, and a cathode layer 106. The electrochemical cell may further include a cathode current collector 108 and an anode current collector 110.

[0108] The cathode layer 106 can include a cathode active material such as nickel-manganese-cobalt (''NMC''), which can be Li(Ni a Co b Mn c )O2 (0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1) or for example NMC 111 (LiNi 0.33 Mn 0.33 Co 0.33 O2), NMC 433 (LiNi 0.4 Mn 0.3 Co 0.3 O2), NMC 532 (LiNi 0.5 Mn 0.3 Co 0. 2O2), NMC 622 (LiNi 0.6 Mn 0.2 Co 0.2 O2), NMC 811 (LiNi 0.8 Mn 0.1 Co 0.1 O2) or combinations thereof. In another embodiment, the cathode active material is, for example, but not limited to, V2O5, V6O 13, MoO3, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1-Y Co Y O2, LiCo 1-Y Mn Y O2, LiNi 1-Y Mn Y O2 (0 ≦ Y < 1), Li(Ni a Co b Mn c )O4 (0 < a < 2, 0 < b < 2, 0 < c < 2, a + b + c = 2), LiMn 2-Z Ni Z O4, LiMn 2-Z Co Z O4 (0 < Z < 2), LiCoPO4, LiFePO4, CuO, Li(Ni a Co b Al c )O2 (0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1), or one or more of coated or uncoated metal oxides such as combinations thereof. In yet another embodiment, the cathode active material can include, but is not limited to, for example, titanium sulfide (TiS2), molybdenum sulfide (MoS2), iron sulfide (FeS, FeS2), copper sulfide (CuS), and nickel sulfide (Ni3S2), or combinations thereof, of coated or uncoated metal sulfides. In still further embodiments, the cathode active material can include elemental sulfur (S). In additional embodiments, the cathode active material can include, but is not limited to, for example, lithium fluoride (LiF), sodium fluoride (NaF), calcium fluoride (CaF2), magnesium fluoride (MgF2), nickel(II) fluoride (NiF2), iron(III) fluoride (FeF3), vanadium(III) fluoride (VF3), cobalt(III) fluoride (CoF3), chromium(III) fluoride (CrF3), manganese(III) fluoride (MnF3), aluminum fluoride (AlF3), and zirconium(IV) fluoride (ZrF4), or combinations thereof, of fluoride cathode active materials.

[0109] The cathode layer 106 can further include one or more conductive additives. Examples of the conductive additive can include metal powder, fiber, filament, or any other material known to conduct electrons. In some embodiments, the one or more conductive additives can include one or more conductive carbon materials such as carbon fiber, graphite, graphene, carbon black, conductive carbon, amorphous carbon, VGCF, and carbon nanotubes. In some embodiments, the conductive additive can be present in the cathode layer 106 in an amount of about 1% to about 10%.

[0110] The cathode layer 106 can further include one or more solid electrolytes. The one or more solid electrolytes can include oxides, oxysulfides, sulfides, halides, nitrides, or any other solid electrolyte known in the art. In some preferred embodiments, the one or more solid electrolytes can include sulfide solid electrolytes. In some embodiments, the solid electrolyte includes a combination of one or more materials, for example, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-S-SiS2-LiCl, Li2S-S-SiS2-B2S3-LiI, Li2S-S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers and Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-S-SiS2-Li3PO4, and Li2S-S-SiS2-Li x MO y (where x and y are positive numbers and M is P, Si, Ge, B, Al, Ga or In). In another embodiment, the solid electrolyte is Li3PS4, Li4P2S6, Li7P3S 11 、Li 10 GeP2S 12 、Li 10 SnP2S 12It may be one or more of them. In a further embodiment, the solid electrolyte may be one or more of Li6PS5Cl, Li6PS5Br, Li6PS5I, and may also be of the formula Li 7-y PS 6-y X y where "X" represents at least one halogen and / or at least one pseudohalogen, 0 < y ≦ 2.0, at least one halogen may be one or more of F, Cl, Br, I, and at least one pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN. In yet another embodiment, the solid electrolyte is of the formula Li 8-y-z P2S 9-y-z X y W z (where "X" and "W" represent at least one halogen element and pseudohalogen, where 0 ≦ y ≦ 1 and 0 ≦ z ≦ 1), the halogen may be one or more of F, Cl, Br, I, and the pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN. In some embodiments, the solid electrolyte can be present in the cathode layer 106 in an amount of about 5% to about 20%. The halide solid electrolyte can have a structure Li-M-X, where M is a metal element and X is a halogen. These can be represented by the general formula Li α M 4+ β N 3+ (1-β) X Ω Y (6-Ω) where 0 ≦ β ≦ 1; 0 ≦ Ω ≦ 6; α = 6 - [(β * 4) + (1 - β) * 3]; X and Y are halogens, for example, F, Cl, Br, I; M is an element with an oxidation number of 4+, such as Ti, Zr, Hf, and Rf; N is an element with an oxidation number of 3+, such as Ga, In, and Tl, Sc, Y, Fe, Ru, Os, Er. Examples of halide electrolytes include Li2ZrCl6, Li3InCl6, Li 2.25 Hf 0.75 Fe 0.25 Cl4Br2.

[0111] In other embodiments, the cathode layer can include a semi-solid electrolyte or a liquid electrolyte.

[0112] The cathode layer 106 can further include one or more binders. In some embodiments, examples of the binder can include fluororesins containing vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), and their derivatives as structural units. Specific examples thereof can include homopolymers such as polyvinylidene fluoride (PVdF), polyhexafluoropropylene (PHFP), and polytetrafluoroethylene (PTFE), and binary copolymers such as a copolymer of VdF and HFP, such as poly(vinylidene fluoride - hexafluoropropylene) copolymer (PVdF - HFP). In another embodiment, the binder is not limited thereto, and for example, one or more of thermoplastic elastomers such as styrene - butadiene rubber (SBR), styrene - butadiene - styrene copolymer (SBS), styrene - isoprene block copolymer (SIS), styrene - ethylene - butylene - styrene (SEBS), polyacrylonitrile (PAN), nitrile - butadiene rubber (NBR), polybutadiene, polyisoprene, poly(methacrylate) nitrile - butadiene rubber (PMMA - NBR) may be used. In yet another embodiment, the binder is not limited thereto, and for example, one or more of acrylic resins such as polymethyl (meth)acrylate, polyethyl (meth)acrylate, polyisopropyl (meth)acrylate, polyisobutyl (meth)acrylate, polybutyl (meth)acrylate may be used. In still another embodiment, the binder is not limited thereto, and for example, one or more of polycondensates such as polyurea, polyamide paper, polyimide, polyester may be used. In other embodiments, examples of the binder can include cellulose - based binders such as carboxymethyl cellulose (CMC). In still yet another embodiment, the binder is not limited thereto, and for example, one or more of nitrile rubbers such as acrylonitrile - butadiene rubber (ABR), polystyrene nitrile - butadiene rubber (PS - NBR), and their mixtures may be used.In a further embodiment, the binder may be one or more of styrenic thermoplastic resins such as, but not limited to, styrene-butadiene rubber (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene block copolymer (SIS), or styrene-ethylene-butylene-styrene block copolymer (SEBS). In other embodiments, the binder may comprise one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations thereof, or derivatives thereof.

[0113] In some embodiments, the binder can include one or more rheology-modifying components. In some preferred embodiments, when the binder includes one or more rheology-modifying components, the binder further includes one or more additional binders or polymers other than the rheology-modifying components. In some aspects, the binder can be present in the cathode layer 106 in an amount of about 0% to about 5%.

[0114] The separator layer 104 (also referred to herein as the "electrolyte layer") can include one or more solid electrolytes. The one or more solid electrolytes can include oxides, oxysulfides, sulfides, halides, nitrides, or any other solid electrolytes known in the art. In some preferred embodiments, the one or more solid electrolytes can include sulfide solid electrolytes. In some aspects, the one or more sulfide solid electrolytes can include a combination of one or more materials, for example, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-S-SiS2-LiCl, Li2S-S-SiS2-B2S3-LiI, Li2S-S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m Sn (Here, m and n are positive numbers, and Z is Ge, Zn, or Ga), Li2S - GeS2, Li2S - S - SiS2 - Li3PO4, and Li2S - S - SiS2 - Li x MO y (Here, x and y are positive numbers, and M is P, Si, Ge, B, Al, Ga, or In) can be included. In some embodiments, one or more solid electrolyte materials are Li3PS4, Li4P2S6, Li7P3S 11 , Li 10 GeP2S 12 , Li 10 SnP2S 12 may be. In another embodiment, one or more solid electrolyte materials may be Li6PS5Cl, Li6PS5Br, Li6PS5I, and may also be represented by the formula Li 7-y PS 6-y X y , where "X" represents at least one halogen and / or at least one pseudohalogen, 0 < y ≦ 2.0, the halogen may be one or more of F, Cl, Br, I, and the pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN. In another embodiment, one or more solid electrolyte materials may be represented by the formula Li 8-y-z P2S 9-y-z X y W z (where "X" and "W" represent at least one halogen and / or at least one pseudohalogen, 0 ≦ y ≦ 1 and 0 ≦ z ≦ 1), the halogen may be one or more of F, Cl, Br, I, and the pseudohalogen may be one or more of N, NH, NH2, NO, NO2, BF4, BH4, AlH4, CN, and SCN. The halide solid electrolyte can have a structure Li - M - X, where M is a metal element and X is a halogen. These are of the general formula Li α M 4+ β N 3+ (1-β) X Ω Y (6-Ω)It can be represented by, where 0 ≤ β ≤ 1; 0 ≤ Ω ≤ 6; α = 6 - [(β * 4) + (1 - β) * 3]; X and Y are halogens, for example, F, Cl, Br, I; M is an element with an oxidation number of 4+, such as Ti, Zr, Hf, and Rf; N is an element with an oxidation number of 3+, such as Ga, In, and Tl, Sc, Y, Fe, Ru, Os, Er. Examples of halide electrolytes include Li2ZrCl6, Li3InCl6, Li 2.25 Hf 0.75 Fe 0.25 Cl4Br2 can be mentioned.

[0115] In other embodiments, the separator layer can include a semi-solid electrolyte or a liquid electrolyte.

[0116] The separator layer 104 can further include one or more binders. In some embodiments, examples of the binder can include fluororesins containing vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), and their derivatives as structural units. Specific examples thereof can include homopolymers, such as polyvinylidene fluoride (PVdF), polyhexafluoropropylene (PHFP), and polytetrafluoroethylene (PTFE), and binary copolymers, such as a copolymer of VdF and HFP, such as poly(vinylidene fluoride - hexafluoropropylene) copolymer (PVdF - HFP), etc. In another embodiment, the binder can be one or more of thermoplastic elastomers such as, but not limited to, styrene - butadiene rubber (SBR), styrene - butadiene - styrene copolymer (SBS), styrene - isoprene block copolymer (SIS), styrene - ethylene - butylene - styrene (SEBS), polyacrylonitrile (PAN), nitrile - butadiene rubber (NBR), polybutadiene, polyisoprene, poly(methacrylate) nitrile - butadiene rubber (PMMA - NBR), etc. In yet another embodiment, the binder can be one or more of acrylic resins such as, but not limited to, polymethyl (meth)acrylate, polyethyl (meth)acrylate, polyisopropyl (meth)acrylate, polyisobutyl (meth)acrylate, polybutyl (meth)acrylate, etc. In still another embodiment, the binder can be one or more of polycondensates such as, but not limited to, polyurea, polyamide paper, polyimide, polyester, etc. In still further one embodiment, the binder can be one or more of nitrile rubbers such as, but not limited to, acrylonitrile - butadiene rubber (ABR), polystyrene nitrile - butadiene rubber (PS - NBR), and their mixtures, etc. In some embodiments, the binder can include one or more rheology - modifying components.In some preferred embodiments, when the binder contains one or more rheology-modifying components, the binder further contains one or more additional binders or polymers other than the rheology-modifying components. In some aspects, the binder can be present in the separator layer 104 in an amount of about 0 wt% to about 20 wt%.

[0117] In some embodiments, the separator layer 104 can have a thickness of about 10 to 40 μm. In some aspects, the separator layer 104 can have a thickness of about 10 μm to about 20 μm, about 10 μm to about 30 μm, about 20 μm to about 30 μm, about 20 μm to about 40 μm, or about 30 μm to about 40 μm. In some additional aspects, the separator layer 104 can have a thickness of about 10 μm, about 11 μm, about 12 μm, about 13 μm, about 14 μm, about 15 μm, about 16 μm, about 17 μm, about 18 μm, about 19 μm, about 20 μm, about 21 μm, about 22 μm, about 23 μm, about 24 μm, about 25 μm, about 26 μm, about 27 μm, about 28 μm, about 29 μm, about 30 μm, about 31 μm, about 32 μm, about 33 μm, about 34 μm, about 35 μm, about 36 μm, about 37 μm, about 38 μm, about 39 μm, or about 40 μm.

[0118] The cathode current collector 108 is disposed adjacent to the cathode layer 106, and the anode current collector 110 is disposed adjacent to the first anode layer 100. The cathode current collector 108 and the anode current collector 110 can include one or more of copper, nickel, titanium, stainless steel, magnesium, iron, zinc, indium, germanium, silver, platinum, or gold. In some embodiments, the cathode current collector 108 or the anode current collector 110 can have a thickness of about 5 μm to about 10 μm. In a preferred embodiment, the cathode current collector 108 includes aluminum, nickel and / or steel. In an additional preferred embodiment, the anode current collector 110 includes copper.

[0119] The electrochemical cell is capable of cyclic operation under the application of a stack pressure up to 3000 psi. In some embodiments, the stack pressure may be about 3000 psi or less, about 2500 psi or less, about 2000 psi or less, about 1500 psi or less, about 1000 psi or less, about 750 psi or less, about 500 psi or less, or about 250 psi or less. In an exemplary embodiment, a stack pressure of about 1500 psi or less is applied to the assembly. In some additional embodiments, the stack pressure applied to the assembly may be from about 100 psi to about 250 psi, from about 100 psi to about 500 psi, from about 100 psi to about 750 psi, from about 100 psi to about 1000 psi, from about 100 psi to about 1500 psi, from about 100 psi to about 2000 psi, from about 100 psi to about 2500 psi, from about 100 psi to about 3000 psi, from about 250 psi to about 3000 psi, from about 500 psi to about 3000 psi, from about 750 psi to about 3000 psi, from about 1000 psi to about 3000 psi, from about 1500 psi to about 3000 psi, from about 2000 psi to about 3000 psi, from about 2500 psi to about 3000 psi, from about 250 psi to about 2500 psi, from about 750 psi to about 2000 psi, or from about 1000 psi to about 2000 psi.

[0120] The electrochemical cell is capable of cyclic operation at a temperature from about 10°C to about 50°C. In some embodiments, the electrochemical cell is capable of cyclic operation at a temperature from about 10°C to about 20°C, from about 10°C to about 30°C, from about 10°C to about 40°C, from about 10°C to about 50°C, from about 20°C to about 30°C, from about 20°C to about 40°C, from about 20°C to about 50°C, from about 30°C to about 40°C, from about 30°C to about 50°C, or from about 40°C to about 50°C. For example, the electrochemical cell is capable of cyclic operation at a temperature of about 10°C, about 15°C, about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, or about 50°C.

[0121] Generally, when a relatively high stack pressure is applied during the first cell cycle, the electrochemical cell can have a greater capacity retention rate compared to an electrochemical cell with a relatively low stack pressure applied during the first cell cycle. Without wishing to be bound by theory, the increase in stack pressure improves the contact between particles and layers, reduces resistance, and promotes the formation of vertical cracks. However, if the stack pressure is excessively high, there is a risk of the cell short-circuiting.

[0122] Generally, the capacity retention rate of the electrochemical cell of the present disclosure can be increased compared to an electrochemical cell having a single-layer anode. The capacity retention rate is an index indicating the capacity of the electrochemical cell after cycle operation as a percentage of the initial capacity of the electrochemical cell. The capacity retention rate of the electrochemical cell of the present disclosure can be up to about 99.9%. For example, the capacity retention rate of the electrochemical cell can be about 99.9%, about 99.5%, about 99%, about 95%, about 90%, about 85%, about 80%, about 99.9% to about 99.5%, about 99.9% to about 95%, about 99.9% to about 90%, about 99.9% to about 85%, about 99.9% to about 80%. Further, the capacity retention rate of the electrochemical cell can be at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 99%, at least about 99.5%, or at least about 99.9%. The capacity retention rate can be at least 80% after about 100 cycles, 200 cycles, 300 cycles, 400 cycles, 500 cycles, 600 cycles, 700 cycles, 800 cycles, or after more than 800 cycles.

[0123] Furthermore, the discharge capacity of the electrochemical cell of the present disclosure can be stable over a greater number of cycles compared to an electrochemical cell having a single-layer anode. As used herein, a "stable" electrochemical cell is a cell having a discharge capacity of 80% or more of the discharge capacity of the electrochemical cell after the first full cycle. As a non-limiting example, an electrochemical cell having a discharge capacity of 100 mAh after the first cycle is considered stable if the discharge capacity of the cell is 80 mAh or more after 100 cycles. For example, the electrochemical cell can have a stable discharge capacity over at least 100 cycles, at least 150 cycles, at least 200 cycles, at least 250 cycles, at least 300 cycles, at least 400 cycles, at least 500 cycles, at least 600 cycles, at least 700 cycles, or at least 800 cycles.

[0124] The electrochemical cell of the present disclosure can have a lower internal resistance compared to an electrochemical cell having a single-layer anode.

[0125] When an electrochemical cell having a single-layer anode is cycled, the anode layer tends to separate from the separator layer due to the expansion and contraction of the anode. In the electrochemical cell of the present disclosure, when the cell is cycled at a stack pressure of less than 1500 psi, the bilayer anode does not separate from the separator layer.

[0126] Furthermore, since the expansion and contraction of the bilayer anode are reduced, the bilayer anode has better surface contact with the separator layer compared to an electrochemical cell having a single-layer anode. Therefore, the void space existing between the bilayer anode and the separator layer can be reduced compared to an electrochemical cell having a single-layer anode. The surface contact with the separator layer can be determined by SEM imaging.

[0127] Also provided herein is a method for manufacturing a two-layer anode for use in a solid electrochemical cell. The method can include: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one tackifier, optionally at least one plasticizer, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate; d) casting the second anode layer slurry onto the first anode layer slurry; and e) drying the first anode layer slurry and the second anode layer slurry to form an anode bilayer. In some embodiments, there may be an intermediate drying step including drying the first layer slurry before step d). In steps a) and b), the components for forming the slurry can be mixed in any order or sequence. As a non-limiting example, it is also possible to add the solvent after mixing the anode active material, at least one solid electrolyte material, and at least one binder material to form a slurry. Also, as another non-limiting example, it is possible to sequentially add the anode active material, at least one solid electrolyte material, and at least one binder material while mixing them into the solvent.

[0128] In an alternative embodiment, the method can include: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one tackifier, optionally at least one plasticizer, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate and drying the first anode layer slurry; and d) casting the second anode layer slurry onto the first anode layer slurry and drying the second anode layer slurry.

[0129] In some embodiments, the solvent can be selected from one of, but not limited to, aprotic hydrocarbons, esters, ethers, or nitriles. In another aspect, the aprotic hydrocarbon can be selected from one of, but not limited to, xylene, toluene, benzene, methylbenzene, hexane, heptane, octane, alkane, isoparaffinic hydrocarbons, or combinations thereof. In another aspect, the ester can be selected from one of, but not limited to, butyl butyrate, isobutyl isobutyrate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, or combinations thereof. In another aspect, the ether can be selected from one of, but not limited to, diethyl ether, dibutyl ether, benzyl ether, or combinations thereof. In another aspect, the nitrile can be selected from one of, but not limited to, acetonitrile, propionitrile, butyronitrile, pyrrolidine, or combinations thereof. The solvent used for forming the first layer slurry may be the same as or different from the solvent used for forming the second layer slurry.

[0130] By densifying the anode bilayer after drying the anode bilayer on a substrate, the density of the anode bilayer can be increased. The method of densification is well known to those skilled in the art. In a preferred embodiment, densification is achieved by calendaring or by linear pressing, such as linear pressing with a linear press. In some embodiments, the temperature during densification can be from about 80 °C to about 140 °C. It will be understood that the density of the anode layer depends on the formulation of the anode layer and the conditions of densification. Without wishing to be bound by theory, an increase in the density of the anode bilayer results in a decrease in the porosity of the anode bilayer, thereby improving the contact between particles and reducing the resistance of the anode bilayer.

[0131] Exemplary embodiments Embodiment 1: An anode structure, the anode structure comprising: A first anode layer The first anode layer is operably in contact with a second anode layer, and the first anode layer and the second anode layer each comprise An anode active material, A binder And The second anode layer further comprises a solid electrolyte material, The first anode layer optionally comprises a solid electrolyte material, An anode structure.

[0132] Embodiment 2: The anode structure according to Embodiment 1, wherein the anode active material is present in an amount of about 50% by weight or more of the first layer in the first layer.

[0133] Embodiment 3: The anode structure according to Embodiment 1 or 2, wherein the anode active material is present in an amount of about 20% to about 70% by weight of the second anode layer in the second anode layer.

[0134] Embodiment 4: The anode structure according to any one of Embodiments 1 to 3, wherein the anode active material of the first anode layer comprises an inorganic material.

[0135] Embodiment 5: The anode structure according to Embodiment 4, wherein the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof.

[0136] Embodiment 6: The anode structure according to Embodiment 5, wherein the inorganic material is silicon, a silicon alloy, or a combination thereof.

[0137] Embodiment 7: The anode structure according to any one of Embodiments 1 to 6, wherein the first anode layer comprises about 5% or less of a solid electrolyte material.

[0138] Embodiment 8: The anode structure according to any one of Embodiments 1 to 7, wherein the first anode layer contains a solid electrolyte material of about 1% or less.

[0139] Embodiment 9: The anode structure according to any one of Embodiments 1 to 8, wherein the first anode layer does not contain a solid electrolyte material.

[0140] Embodiment 10: The anode structure according to any one of Embodiments 1 to 9, wherein the solid electrolyte material includes a sulfide-based solid electrolyte material.

[0141] Embodiment 11: The anode structure according to any one of Embodiments 1 to 10, wherein the binder in the first anode layer is different from the binder in the second anode layer.

[0142] Embodiment 12: The anode structure according to any one of Embodiments 1 to 11, wherein the binder includes one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations thereof, or derivatives thereof.

[0143] Embodiment 13: The anode structure according to any one of Embodiments 1 to 12, further including a current collector that is operably in contact with the first anode layer.

[0144] Embodiment 14: The anode structure according to any one of Embodiments 1 to 13, wherein the first anode layer or the second anode layer further contains a carbon-based conductive additive.

[0145] Embodiment 15: The anode structure according to claim 14, wherein the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0146] Embodiment 16: The anode structure according to claim 1, wherein the second anode layer further contains a tackifier.

[0147] Embodiment 17: The anode structure according to claim 16, wherein the adhesion - imparting agent contains a hydrocarbon resin.

[0148] Embodiment 18: The anode structure according to claim 1, wherein the second anode layer further contains a plasticizer.

[0149] Embodiment 19: The anode structure according to claim 18, wherein the plasticizer contains dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

[0150] Embodiment 20: The anode structure further includes a third anode layer, and the third anode layer contains an anode active material, a binder, a conductive additive, and a solid electrolyte material and, the amounts in weight % of the anode active material, binder, conductive additive and / or solid electrolyte material in the third anode layer are different from the amounts in the first anode layer and the second anode layer. The anode structure according to claim 1.

[0151] Embodiment 21: A method for manufacturing the anode structure according to claim 1, comprising: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode layer slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate; d) casting the second anode layer slurry onto the first anode layer slurry; and e) drying the first anode layer slurry and the second anode layer slurry to form an anode structure The method comprising.

[0152] Embodiment 22: The method according to claim 21, wherein the mixing in step a) includes mixing an anode active material, at least one solid electrolyte material, and at least one binder material, and substantially excluding the solid electrolyte material when mixing.

[0153] Embodiment 23: The method according to claim 21 or 22, wherein at least one solid electrolyte material is not included in the mixing in step a).

[0154] Embodiment 24: A method for manufacturing the anode assembly according to claim 1, comprising: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode layer slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one plasticizer, optionally at least one tackifier, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate and drying the first anode layer slurry; d) casting the second anode layer slurry onto the first anode layer slurry and drying the second anode layer slurry The method comprising.

[0155] Embodiment 25: An assembly including a solid two-layer anode, wherein the two-layer anode includes: A first anode layer, wherein the first anode layer includes: A first anode active material, which is present in an amount of about 50% by weight or more of the first anode layer in the first anode layer, a first anode active material, A first binder, A first conductive additive And is included, the first anode layer; A second anode layer, wherein the second anode layer includes: A second anode active material, where the second anode active material is present in the second anode layer in an amount of about 20 wt% to about 70 wt% of the second anode layer, the second anode active material, and a second binder, and a second conductive additive, and a solid electrolyte material be included, the second anode layer A structure including

[0156] Embodiment 26: The structure according to claim 25, wherein the first anode layer substantially does not contain a solid electrolyte material.

[0157] Embodiment 27: The structure according to claim 25, wherein the first anode layer lacks a solid electrolyte material.

[0158] Embodiment 28: The structure according to claim 25, wherein the anode active material is present in the first layer in an amount of about 50 wt% or more of the first layer.

[0159] Embodiment 29: The structure according to claim 25, wherein the anode active material is present in the second anode layer in an amount of about 20 wt% to about 50 wt% of the second anode layer.

[0160] Embodiment 30: The structure according to claim 25, wherein the anode active material of the first anode layer contains an inorganic material.

[0161] Embodiment 31: The structure according to claim 30, wherein the inorganic material is selected from the group consisting of silicon, silicon alloy, tin, tin alloy, germanium, germanium alloy, and combinations thereof.

[0162] Embodiment 32: The structure according to claim 31, wherein the inorganic material is silicon, silicon alloy, or a combination thereof.

[0163] Embodiment 33: The structure according to claim 25, wherein the first anode layer contains about 5% or less of a solid electrolyte material.

[0164] Embodiment 34: The structure according to claim 25, wherein the first anode layer contains a solid electrolyte material of about 1% or less.

[0165] Embodiment 35: The structure according to claim 25, wherein the solid electrolyte material includes a sulfide-based solid electrolyte material.

[0166] Embodiment 36: The structure according to claim 25, wherein the binder in the first anode layer is different from the binder in the second anode layer.

[0167] Embodiment 37: The structure according to claim 25, wherein the binder includes one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations thereof, or derivatives thereof.

[0168] Embodiment 38: The structure according to claim 25, further comprising a current collector in operable contact with the first anode layer.

[0169] Embodiment 39: The structure according to claim 25, wherein the first anode layer or the second anode layer further contains a carbon-based conductive additive.

[0170] Embodiment 40: The structure according to claim 39, wherein the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

[0171] Embodiment 41: The structure according to claim 25, wherein the second anode layer further contains a tackifier.

[0172] Embodiment 42: The structure according to claim 41, wherein the tackifier includes a hydrocarbon resin.

[0173] Embodiment 43: The structure according to claim 25, wherein the second anode layer further contains a plasticizer.

[0174] Embodiment 44: The structure according to claim 43, wherein the plasticizer comprises dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

[0175] Embodiment 45: A structure comprising a solid bilayer anode, wherein the bilayer anode is a first anode layer, and the first anode layer contains a first anode active material in an amount of about 60 wt% or more of the first anode layer, contains a first solid electrolyte material in an amount of about 20 wt% to about 30 wt% of the first anode layer, contains a first binder in an amount of about 0 wt% to about 20 wt% of the first anode layer, and the first anode layer; is a second anode layer, and the second anode layer contains a second anode active material in an amount of about 20 wt% to about 70 wt% of the second anode layer, contains a second solid electrolyte material in an amount of about 45 wt% or less of the second anode layer, contains a second binder in an amount of about 10 wt% or less of the second anode layer, and the second anode layer and the structure.

[0176] Embodiment 46: An electrochemical cell, wherein the electrochemical cell comprises a bilayer anode, a separator layer, and a cathode layer and the bilayer anode comprises a first anode layer, the first anode layer being operably in contact with the second anode layer, and the first anode layer and the second anode layer each comprise an anode active material, a binder and the second anode layer further comprises a solid electrolyte material, and the first anode layer optionally comprises a solid electrolyte material. The electrochemical cell.

[0177] Embodiment 47: The electrochemical cell according to claim 46, further comprising a first current collector operably contacting the first anode layer of the bilayer anode.

[0178] Embodiment 48: The structure according to claim 46, wherein the first anode layer substantially does not contain a solid electrolyte material.

[0179] Embodiment 49: The structure according to claim 46, wherein the first anode layer lacks a solid electrolyte material.

[0180] Those skilled in the art will understand that by implementing the above method for forming the anode bilayer, it is possible to form an anode structure having three or more layers by repeating the above steps.

[0181] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In the practice or testing of the subject matter of this disclosure, any methods and materials similar or equivalent to those described herein can be used, but the preferred methods and materials are described. For the purposes of this disclosure, the following terms are defined below.

[0182] Concentrations, amounts, and other numerical data may be presented or expressed herein in a range format. Such a range format is used merely for convenience and brevity, and in such a range format, not only the numerical values explicitly listed as the limits of the range but also any individual numerical values or sub-ranges subsumed within that range should be construed flexibly as if each numerical value and sub-range were explicitly listed. As an example, a numerical range of "about 2 to about 50" should be construed to include not only the explicitly listed values of 2 to 50 but also all individual values and sub-ranges within the indicated range. Thus, included within this numerical range are individual numerical values such as, for example, 2, 2.4, 3, 3.7, 4, 5.5, 10, 10.1, 14, 15, 15.98, 20, 20.13, 23, 25.06, 30, 35.1, 38.0, 40, 44, 44.6, 45, 48, and sub-ranges such as, for example, 1 to 3, 2 to 4, 5 to 10, 5 to 20, 5 to 25, 5 to 30, 5 to 35, 5 to 40, 5 to 50, 2 to 10, 2 to 20, 2 to 30, 2 to 40, 2 to 50, etc. The same principle applies to ranges where only one numerical value is listed as the minimum or maximum value. Further, such an interpretation should apply regardless of the magnitude of the range or property described.

[0183] The term "about" is self-evident to those of ordinary skill in the art and may vary to some extent depending on the context in which the term is used. When used herein in reference to measurable values such as amounts, durations, etc., the term "about" means that variations of ±10%, such as ±5%, ±1%, and ±0.1% of a particular value are included when such variations are appropriate for the practice of the disclosed method.

[0184] In the present disclosure, terms such as "comprises," "comprising," "containing," and "having" can have the meanings ascribed to such terms in U.S. patent law, can mean "includes," "including," etc., and are generally interpreted as open-ended terms. The terms "consisting of" or "consists of" are closed terms, and such terms include only the components, structures, steps, etc. specifically listed in connection with such terms and those in accordance with U.S. patent law. "Consisting essentially of" or "consists essentially of" generally has the meaning ascribed to such terms by U.S. patent law. In particular, such terms are generally closed terms, but with the exception that the inclusion of additional items, materials, components, steps, or elements that do not materially affect the basic and novel characteristics or functions of the items used in connection therewith is permitted. For example, trace elements present in a composition that do not affect the nature or characteristics of the composition are permitted under the phrase "consisting essentially of" even if not explicitly listed in the list of items following such term. In this specification, when an open-ended term such as "comprising" or "including" is used, support should be provided directly as if explicitly stated not only for the phrase "consisting essentially of" but also for the phrase "consisting of," and vice versa should be understood to be the case.

Example

[0185] For purposes of illustration and to describe certain embodiments of the present disclosure, examples are set forth below. However, the claims are not limited in any way by the examples set forth herein. Various modifications and variations to the disclosed embodiments will be apparent to those skilled in the art, and such modifications and variations, which are not limited to but include modifications and variations to the chemical structures, substituents, derivatives, formulations, or methods of the present disclosure, can be made without departing from the spirit of the present disclosure and the scope of the appended claims. The definitions of the variable portions of the structures within the schemes herein are equivalent to those at the corresponding positions in the formulas presented herein.

[0186] Example 1: Cycle operation data of a two-layer anode (without tackifier or plasticizer) Four electrochemical cells were fabricated. Two of these electrochemical cells had a single anode layer, and two of these electrochemical cells had the anode bilayer of the present disclosure. The separator layer and cathode layer of each of these four cells were identical. The compositions of the anode layers of these four electrochemical cells are shown in Table 1 below. The styrenic thermoplastic resin and sulfide-based solid electrolyte (SSE) were the same for all electrochemical cells. All percentages are by weight.

Table 1

[0187] These cells were cycled at 29 °C under a stack pressure of 300 psi. The cycle operation data are shown in FIGS. 3A - 3D. The data for Cell No. 1 are shown as open squares (□), the data for Cell No. 2 are shown as diamonds (◇), the data for Cell No. 3 are shown as open circles (○), and the data for Cell No. 4 are shown as filled circles (●). From this data, it was found that the cells with the anode bilayer were stable over more than 100 cycles.

[0188] Example 2: Cycle operation data of a two-layer anode (cell containing tackifier and plasticizer) An electrochemical cell equipped with a two-layer anode and an electrochemical cell equipped with a single-layer anode were fabricated. Three electrochemical cells equipped with a two-layer anode were fabricated, and two electrochemical cells equipped with a single-layer anode were fabricated. The two-layer anode contained a plasticizer and a tackifier in the second anode layer, and the single-layer anode also contained a plasticizer and a tackifier. The plasticizer contained mineral oil. The tackifier contained a hydrocarbon resin. The styrenic thermoplastic resin and the sulfide-based solid electrolyte (SSE) were the same for all the electrochemical cells. The composition of the anode layer of each cell is shown in Table 2 below. All percentages are by weight percentage.

Table 2

[0189] The cycle operation data of these cells are shown in FIGS. 4A to 4C. The two-layer anode is indicated by a filled circle (●), and the single-layer anode is indicated by an open circle (○). The cell equipped with a two-layer anode having a high concentration of styrenic thermoplastic resin, plasticizer, and tackifier at the separator interface had a better capacity retention rate than the cell equipped with a single layer having a styrenic thermoplastic resin, plasticizer, and tackifier. From this data, it was found that when the tackifier and / or plasticizer existed alone, the performance of the anode did not improve. The two-layer structure of the anode provides an improvement in the performance of the electrochemical cell.

[0190] Example 3: Cycle operation data of a two-layer anode (effects of tackifier and plasticizer in a two-layer anode) An electrochemical cell with a two-layer anode was fabricated. Three cells contained a tackifier and a plasticizer in the second anode layer, while three cells contained neither the tackifier nor the plasticizer. The composition of the anode layer of each cell is shown in Table 3 below. The cells were charged over 3 hours, discharged over 3 hours in the first 3 cycles, then charged over 5 hours, and discharged over 5 hours in the remaining cycles. All percentages are weight percentages. [Table 3]

[0191] The cycle operation data of these cells are shown in FIGS. 5A to 5D. The two-layer anode containing the plasticizer and the tackifier is indicated by a solid circle (●), while the two-layer anode having neither the plasticizer nor the tackifier is indicated by an open circle (○). The cells having a high concentration of styrene-based thermoplastic resin, plasticizer, and tackifier at the interface with the separator had a better capacity retention rate compared to the cells equipped with a two-layer anode having only the styrene-based thermoplastic resin.

[0192] Example 4: Cycle operation data of a three-layer anode An electrochemical cell with a three-layer anode of the present disclosure was fabricated. The composition of the anode layer of each cell is shown in Table 4. All percentages are weight percentages. [Table 4]

[0193] Figures 6A to 6D show the cycle operation data of each cell. The data of Cell 1 and Cell 2 are shown as filled circles (●), and the data of Cell 3 and Cell 4 are shown as open circles (○). The cells were cycled at 45 °C, a stack pressure of 300 psi, and in a voltage range of 2.5 to 4.2 V. The cells were charged over 10 hours, discharged over 10 hours for the first 3 cycles, then charged over 5 hours, and discharged over 5 hours for the remaining cycles. From this data, it was found that the discharge capacity of the cells with a three-layer anode decreased more rapidly, but the discharge resistance of the cells with a three-layer anode was significantly lower.

[0194] Example 5: Cycle operation data of a two-layer anode with an uncoated current collector An electrochemical cell was fabricated with a single-layer anode containing 50 wt% silicon and a carbon-coated copper current collector. Also, an electrochemical cell with a two-layer anode was fabricated. The first layer of the two-layer anode (i.e., the layer adjacent to the current collector) contained 80 wt% silicon. The second layer of the two-layer anode contained 40 wt% silicon. Overall, the proportion of silicon in the two-layer anode was the same as that in the single-layer anode. These cells had a current collector containing uncoated copper. The composition of each cell is shown in Table 5.

Table 5

[0195] Figure 7 shows the cycle operation data of each cell. The cells were cycled at 45 °C, a stack pressure of 300 psi, and in a voltage range of 2.5 to 4.2 V. The cells were charged over 10 hours, discharged over 10 hours for the first 3 cycles, then charged over 5 hours, and discharged over 5 hours for the remaining cycles. As is apparent from Figure 7, the cells with a two-layer anode had a more stable cell capacity retention rate over a longer number of cycles compared to the cells with a single-layer anode.

[0196] The above-described features and the features claimed below can be combined in various ways without departing from the technical scope of this specification. Therefore, it should be noted that the matters included in the above description or shown in the attached drawings are illustrative and should not be construed as having a limiting intention. The above-described embodiments are not intended to limit the technical scope of the present invention, but should be regarded as examples of the present invention. In addition to the foregoing embodiments of the present invention, it will be apparent from a consideration of the detailed description and the attached drawings that there are other embodiments of the present invention. Therefore, many combinations, alternative forms, variations, and modifications of the foregoing embodiments of the present invention are included in the technical scope of the present invention even if not explicitly described herein. The following claims are intended to embrace all the comprehensive and specific features described herein, as well as all descriptions of the technical scope of the methods and systems of the present invention, which would be said to be included in the technical scope as a matter of language.

Claims

1. An anode structure, wherein the anode structure comprises a first anode layer and the first anode layer is operably in contact with a second anode layer, and each of the first anode layer and the second anode layer comprises an anode active material and a binder , the second anode layer further comprises a solid electrolyte material and the first anode layer optionally comprises a solid electrolyte material An anode structure.

2. The anode structure according to claim 1, wherein the anode active material is present in the first layer in an amount of about 50 wt% or more of the first layer.

3. The anode structure according to claim 1, wherein the anode active material is present in the second anode layer in an amount of about 20 wt% to about 50 wt% of the second anode layer.

4. The anode structure according to claim 1, wherein the anode active material of the first anode layer comprises an inorganic material.

5. The anode structure according to claim 4, wherein the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof.

6. The anode structure according to claim 5, wherein the inorganic material is silicon, a silicon alloy, or a combination thereof.

7. The anode structure according to claim 1, wherein the first anode layer comprises about 5% or less of a solid electrolyte material.

8. The anode structure according to claim 1, wherein the first anode layer comprises about 1% or less of a solid electrolyte material.

9. The anode structure according to claim 1, wherein the first anode layer does not comprise a solid electrolyte material.

10. The anode structure according to claim 1, wherein the solid electrolyte material comprises a sulfide-based solid electrolyte material.

11. The anode structure according to claim 1, wherein the binder of the first anode layer is different from the binder in the second anode layer.

12. The anode structure according to claim 1, wherein the binder comprises one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations or derivatives thereof.

13. The anode structure according to claim 1, further comprising a current collector that is operably in contact with the first anode layer.

14. The anode structure according to claim 1, wherein the first anode layer or the second anode layer further contains a carbon-based conductive additive.

15. The anode structure according to claim 14, wherein the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

16. The anode structure according to claim 1, wherein the second anode layer further contains a tackifier.

17. The anode structure according to claim 16, wherein the tackifier contains a hydrocarbon resin.

18. The anode structure according to claim 1, wherein the second anode layer further contains a plasticizer.

19. The anode structure according to claim 18, wherein the plasticizer contains dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

20. The anode structure further includes a third anode layer, and the third anode layer contains an anode active material, a binder, a conductive additive, and a solid electrolyte material and, the amounts in weight % of the anode active material, binder, conductive additive, and / or solid electrolyte material in the third anode layer are different from the amounts in the first anode layer and the second anode layer. The anode structure according to claim 1.

21. A method for manufacturing the anode structure according to claim 1, comprising: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode layer slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, optionally at least one plasticizer, optionally at least one tackifier, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate; d) casting the second anode layer slurry onto the first anode layer slurry; and e) drying the first anode layer slurry and the second anode layer slurry to form an anode structure. The method includes the above steps.

22. The method according to claim 21, wherein the mixing in step a) includes mixing an anode active material, at least one solid electrolyte material, and at least one binder material, and substantially excluding the solid electrolyte material when mixing.

23. The method according to claim 21, wherein the mixing in step a) does not include at least one solid electrolyte material.

24. A method for manufacturing the anode assembly according to claim 1, comprising: a) mixing an anode active material, optionally at least one solid electrolyte material, at least one binder material, and a solvent to form a first anode layer slurry; b) mixing an anode active material, at least one solid electrolyte material, at least one binder material, and a solvent to form a second anode layer slurry; c) casting the first anode layer slurry onto a substrate and drying the first anode layer slurry; d) casting the second anode layer slurry onto the first anode layer slurry and drying the second anode layer slurry A method comprising.

25. An assembly comprising a solid two-layer anode, wherein the two-layer anode comprises: A first anode layer, wherein the first anode layer comprises: A first anode active material, wherein the first anode active material is present in an amount of about 50% by weight or more of the first anode layer in the first anode layer, a first anode active material; A first binder; A first conductive additive A first anode layer, which is to be included; A second anode layer, wherein the second anode layer comprises: A second anode active material, wherein the second anode active material is present in an amount of about 20% to about 70% by weight of the second anode layer in the second anode layer, a second anode active material; A second binder; A second conductive additive; A solid electrolyte material A second anode layer, which is to be included; An assembly comprising.

26. The assembly according to claim 25, wherein the first anode layer substantially does not contain a solid electrolyte material.

27. The assembly according to claim 25, wherein the first anode layer lacks a solid electrolyte material.

28. The assembly according to claim 25, wherein the anode active material is present in an amount of about 50% by weight or more of the first layer in the first layer.

29. The structure according to claim 25, wherein the anode active material is present in the second anode layer in an amount of about 20 wt% to about 50 wt% of the second anode layer.

30. The structure according to claim 25, wherein the anode active material of the first anode layer comprises an inorganic material.

31. The structure according to claim 30, wherein the inorganic material is selected from the group consisting of silicon, silicon alloys, tin, tin alloys, germanium, germanium alloys, and combinations thereof.

32. The structure according to claim 31, wherein the inorganic material is silicon, a silicon alloy, or a combination thereof.

33. The structure according to claim 25, wherein the first anode layer comprises a solid electrolyte material of about 5% or less.

34. The structure according to claim 25, wherein the first anode layer comprises a solid electrolyte material of about 1% or less.

35. The structure according to claim 25, wherein the solid electrolyte material comprises a sulfide-based solid electrolyte material.

36. The structure according to claim 25, wherein the binder of the first anode layer is different from the binder in the second anode layer.

37. The structure according to claim 25, wherein the binder comprises one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), or combinations thereof, or derivatives thereof.

38. The structure according to claim 25, further comprising a current collector operably contacting the first anode layer.

39. The structure according to claim 25, wherein the first anode layer or the second anode layer further comprises a carbon-based conductive additive.

40. The structure according to claim 39, wherein the carbon-based conductive additive is selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, carbon nanowires, vapor-grown carbon fibers, activated carbon, and combinations thereof.

41. The structure according to claim 25, wherein the second anode layer further comprises a tackifier.

42. The structure according to claim 41, wherein the tackifier comprises a hydrocarbon resin.

43. The structure according to claim 25, wherein the second anode layer further comprises a plasticizer.

44. The structure according to claim 43, wherein the plasticizer comprises dioctyl phthalate, dibutyl sebacate, mineral oil, or a combination thereof.

45. A structure including a solid bilayer anode, wherein the bilayer anode is a first anode layer, and the first anode layer contains a first anode active material in an amount of about 60 wt% or more of the first anode layer, contains a first solid electrolyte material in an amount of about 20 wt% to about 30 wt% of the first anode layer, contains a first binder in an amount of about 0 wt% to about 20 wt% of the first anode layer, a first anode layer; is a second anode layer, and the second anode layer contains a second anode active material in an amount of about 20 wt% to about 70 wt% of the second anode layer, contains a second solid electrolyte material in an amount of about 45 wt% or less of the second anode layer, contains a second binder in an amount of about 10 wt% or less of the second anode layer, a second anode layer and a structure containing the same.

46. An electrochemical cell, wherein the electrochemical cell comprises a bilayer anode, a separator layer, and a cathode layer wherein the bilayer anode includes a first anode layer, the first anode layer is operably in contact with a second anode layer, and the first anode layer and the second anode layer each include an anode active material, a binder and the second anode layer further includes a solid electrolyte material, wherein the first anode layer optionally includes a solid electrolyte material, an electrochemical cell.

47. The electrochemical cell according to claim 46, further comprising a first current collector operably in contact with the first anode layer of the bilayer anode.

48. The structure according to claim 46, wherein the first anode layer substantially does not contain a solid electrolyte material.

49. The structure according to claim 46, wherein the first anode layer lacks a solid electrolyte material. ​

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