Compositions, devices, and methods of making and use thereof

Abstract

Disclosed herein are compositions, devices, and methods of making and use thereof. For example, disclosed herein are composite materials comprising a plurality of particles comprising silicon (Si) (e.g., a plurality of silicon particles); and a graphene; wherein the plurality of particles comprising silicon are dispersed substantially uniformly on the graphene. Also disclosed herein are electrodes and batteries comprising any of the composite materials disclosed herein.

Description

[0001] COMPOSITIONS, DEVICES, AND METHODS OF MAKING AND USE THEREOF

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to U.S. Provisional Application No.

[0004] 63 / 635,118, filed April 17, 2024, which is hereby incorporated herein by reference in its entirety.

[0005] BACKGROUND

[0006] The exhaustion of fossil fuels and global warming leads to a lot of research efforts to develop eco-friendly energy storage systems. Lithium-ion batteries (LIBs) have attracted considerable attention, due to their high energy density and capacity, high operating voltage, and long cycle life, among other excellent charge-discharge performance characteristics.

[0007] Among various electrode materials, silicon (Si) is a promising candidate as an electrode material for next-generation Lithium-ion batteries. However, Si anodes suffer from a variety of limitations. Compositions and devices with improved properties for use as anodes in lithium-ion batteries are needed. The compositions, methods, and devices discussed herein addresses these and other needs.

[0008] SUMMARY

[0009] In accordance with the purposes of the disclosed compositions, methods, and devices as embodied and broadly described herein, the disclosed subject matter relates to devices and methods of making and use thereof.

[0010] For example, disclosed herein are composite materials comprising a plurality of particles comprising silicon (Si) (e.g., a plurality of silicon particles); and a graphene; wherein the plurality of particles comprising silicon are dispersed substantially uniformly on the graphene.

[0011] In some examples, the plurality of particles comprising silicon have an average particle size of from 1 nanometers (nm) to 500 nanometers (nm). In some examples, the plurality of particles comprising silicon have an average particle size of from 1 nm to 100 nm.

[0012] In some examples, the graphene comprises graphene oxide.

[0013] In some examples, the graphene comprises reduced graphene oxide.

[0014] Also disclosed herein are electrodes and batteries comprising any of the composite materials disclosed herein.

[0015] For example, also disclosed herein are electrodes, such as anodes, comprising any of the composite materials disclosed herein. In some examples, the electrode is stable, fast charging, or a combination thereof.

[0016] In some examples, the electrode exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 20 cycles or more (e.g., 50 cycles or more, 100 cycles or more, or 150 cycles or more).

[0017] In some examples, the electrode exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C.

[0018] Also disclosed herein are electrochemical cells comprising any of the electrodes disclosed herein.

[0019] Also disclosed herein are devices, such as batteries, comprising any of the electrodes disclosed herein.

[0020] Also disclosed herein are batteries comprising any of the electrodes disclosed herein.

[0021] In some examples, the battery is a lithium-ion battery.

[0022] In some examples, the battery is rechargeable.

[0023] In some examples, the battery exhibits improved cycle life, improved stability, high-rate capabilities (e.g., fast-charging), improved performance, or a combination thereof.

[0024] In some examples, the battery exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 100 cycles or more (e.g., 150 cycles or more).

[0025] In some examples, the battery exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C.

[0026] Also disclosed herein are systems comprising one or more of any of the batteries disclosed herein. In some examples, the system is an energy storage system.

[0027] Also disclosed herein are articles comprising one or more of any of the batteries disclosed herein. In some examples, the article comprises a vehicle, an electronic device, or a combination thereof.

[0028] Also disclosed herein are methods of use of any of the composite materials disclosed herein, any of the electrodes disclosed herein, any of the electrochemical cells disclosed herein, any of the devices disclosed herein, any of the batteries disclosed herein, any of the systems disclosed herein, any of the articles disclosed herein, or a combination thereof.

[0029] Also disclosed herein are methods of making any of the composite materials disclosed herein.

[0030] In some examples, the method comprises: contacting a first dispersion with a second dispersion to form a mixture; the first dispersion comprising the plurality of silicon particles dispersed in a first solvent; the second dispersion comprising graphene dispersed in a second solvent; and hydrothermally treating the mixture to thereby form the composite material.

[0031] In some examples, the method further comprises forming the first dispersion by dispersing the plurality of silicon particles in the first solvent.

[0032] In some examples, the method further comprises forming the second dispersion by dispersing the graphene in the second solvent.

[0033] In some examples, the first solvent and the second solvent are the same or different.

[0034] In some examples, the first solvent and / or the second solvent is each independently an aqueous solvent.

[0035] In some examples, the method further comprises making the plurality of silicon particles. In some examples, the method further comprises making the graphene.

[0036] In some examples, the contacting and / or dispersing comprises agitation, such as sonication.

[0037] In some examples, hydrothermally treating the mixture comprises heating the mixture at a temperature (e.g., from 150-200°C, such as 180°C) for an amount of time (e.g., from 4-12 hours, such as 6 hours).

[0038] In some examples, the method further comprises additional processing after the hydrothermal treatment to form the composite material. In some examples, the additional processing comprises grinding and / or drying.

[0039] Additional advantages of the disclosed compositions, devices, and methods will be set forth in part in the description which follows, and in part will be obvious from the description. The advantages of the disclosed compositions, devices, and methods will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed devices and methods, as claimed.

[0040] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

[0041] BRIEF DESCRIPTION OF THE FIGURES

[0042] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects of the disclosure, and together with the description, serve to explain the principles of the disclosure. However, the present disclosure is not limited to the precise arrangements shown, and the drawings are not necessarily drawn to scale.

[0043] Figure 1. Schematic of the preparation of Si / G nanocomposite.

[0044] Figure 2A-Figure 2D. SEM images of (Figure 2A and Figure 2B) graphene (G) and (Figure 2C and Figure 2D) Si / G samples.

[0045] Figure 3. XRD patterns of G, Si, and Si / G samples.

[0046] Figure 4 A. XPS data: survey spectra.

[0047] Figure 4B. XPS data: deconvoluted Si 2p spectra.

[0048] Figure 4C. XPS data: deconvoluted O ls spectra of G and Si / G samples.

[0049] Figure 5A-Figure 5D. Cycling performance (Figure 5A and Figure 5B) and cycle tested (Figure 5C and Figure 5D) by adding a capacity-limited charging to 1500 mA h / g of G, Si, and Si / G samples in half-cells at 25 °C in the voltage range from 0.05 V to 1.0 Vvs.Li.

[0050] Figure 6A. Different rate capability (0.05 C, 1 C, 3 C, 5 C, 7 C, and 10 C) for fast charge of Si / G nanocomposite anode.

[0051] Figure 6B. Voltage profiles of Si anode in half-cells at 25 °C for fast charging in the voltage range from 0.05 V to 1.0 V.

[0052] Figure 6C. Voltage profiles of Si / G anode in half-cells at 25 °C for fast charging in the voltage range from 0.05 V to 1.0 V.

[0053] Figure 7A-Figure 7D. Charge and discharge profiles and corresponding dO / dF profiles of (Figure 7A and Figure 7B) Si, and (Figure 7C and Figure 7D) Si / G anodes in half-cells at 25 °C.

[0054] Figure 8A-Figure 8B. Nyquist plots of (Figure 8A) Si and (Figure 8B) Si / G anodes in half-cells at 4th, 50th, and 100thcycles at 25 °C.

[0055] DETAILED DESCRIPTION

[0056] The compositions, methods, and devices described herein may be understood more readily by reference to the following detailed description of specific aspects of the disclosed subject matter and the Examples included therein.

[0057] Before the present compositions, methods, and devices are disclosed and described, it is to be understood that the aspects described below are not limited to specific synthetic methods or specific reagents, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0058] Also, throughout this specification, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which the disclosed matter pertains. The references disclosed are also individually and specifically incorporated by reference herein for the material contained in them that is discussed in the sentence in which the reference is relied upon.

[0059] In this specification and in the claims that follow, reference will be made to a number of terms, which shall be defined to have the following meanings.

[0060] Throughout the description and claims of this specification the word “comprise” and other forms of the word, such as “comprising” and “comprises,” means including but not limited to, and is not intended to exclude, for example, other additives, components, integers, or steps.

[0061] As used in the description and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a composition” includes mixtures of two or more such compositions, reference to “an agent” includes mixtures of two or more such agents, reference to “the component” includes mixtures of two or more such components, and the like.

[0062] “Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0063] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. By “about” is meant within 5% of the value, e.g., within 4, 3, 2, or 1% of the value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0064] Values can be expressed herein as an “average” value. “Average” generally refers to the statistical mean value.

[0065] By “substantially” is meant within 5%, e.g., within 4%, 3%, 2%, or 1%.

[0066] “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0067] It is understood that throughout this specification the identifiers “first” and “second” are used solely to aid in distinguishing the various components and steps of the disclosed subject matter. The identifiers “first” and “second” are not intended to imply any particular order, amount, preference, or importance to the components or steps modified by these terms.

[0068] References in the specification and concluding claims to parts by weight of a particular element or component in a composition denotes the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight component Y, X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.

[0069] A weight percent (wt. %) of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included.

[0070] The term “or combinations thereof’ as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof’ is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CAB ABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0071] Compositions and Devices

[0072] Described herein are compositions and devices.

[0073] For example, described herein are composite materials comprising: a plurality of particles comprising silicon (Si) (e.g., a plurality of silicon particles); and a graphene; wherein the plurality of particles comprising silicon are dispersed substantially uniformly on the graphene.

[0074] The plurality of silicon particles can comprise particles of any shape desired for the specific application (e.g., a sphere, a rod, a quadrilateral, an ellipse, a triangle, a polygon, etc.). In some examples, the plurality of silicon particles can have an irregular shape, a regular shape, an isotropic shape, an anisotropic shape, or a combination thereof.

[0075] The plurality of silicon particles can have an average particle size. “Average particle size” and “mean particle size” are used interchangeably herein, and generally refer to the statistical mean particle size of the particles in a population of particles. For example, the average particle size for a plurality of particles with a substantially spherical shape can comprise the average diameter of the plurality of particles. For a particle with a substantially spherical shape, the diameter of a particle can refer, for example, to the hydrodynamic diameter. As used herein, the hydrodynamic diameter of a particle can refer to the largest linear distance between two points on the surface of the particle. For an anisotropic particle, the average particle size can refer to, for example, the average maximum dimension of the particle (e.g., the length of a rod shaped particle, the diagonal of a cube shape particle, the bisector of a triangular shaped particle, etc.). For an anisotropic particle, the average particle size can refer to, for example, the hydrodynamic size of the particle. Mean particle size can be measured using methods known in the art, such as evaluation by electron microscopy (e.g., scanning electron microscopy, transmission electron microscopy, or a combination thereof) and / or dynamic light scattering.

[0076] In some examples, the plurality of particles comprising silicon can have an average particle size of 1 nanometer (nm) or more (e.g., 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, 45 nm or more,

[0077] 50 nm or more, 55 nm or more, 60 nm or more, 65 nm or more, 70 nm or more, 75 nm or more,

[0078] 80 nm or more, 85 nm or more, 90 nm or more, 95 nm or more, 100 nm or more, 110 nm or more, 120 nm or more, 130 nm or more, 140 nm or more, 150 nm or more, 175 nm or more, 200 nm or more, 225 nm or more, 250 nm or more, 275 nm or more, 300 nm or more, 325 nm or more, 350 nm or more, 375 nm or more, 400 nm or more, 425 nm or more, or 450 nm or more). In some examples, the plurality of particles comprising silicon can have an average particle size of 500 nanometers (nm) or less (e.g., 475 nm or less, 450 nm or less, 425 nm or less, 400 nm or less, 375 nm or less, 350 nm or less, 325 nm or less, 300 nm or less, 275 nm or less, 250 nm or less, 225 nm or less, 200 nm or less, 175 nm or less, 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, 95 nm or less, 90 nm or less, 85 nm or less,

[0079] 80 nm or less, 75 nm or less, 70 nm or less, 65 nm or less, 60 nm or less, 55 nm or less, 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, or 5 nm or less). The average particle size of the plurality of silicon particle can range from any of the minimum values described above to any of the maximum values described above. For example, the plurality of silicon particles can have an average particle size of from 1 nanometers (nm) to 500 nanometers (nm) (e.g., from 1 to 250 nm, from 250 to 500 nm, from 1 to 100 nm, from 100 to 200 nm, from 200 to 300 nm, from 300 to 400 nm, from 400 to 500 nm, from 1 to 400 nm, from 1 to 300 nm, from 1 to 200 nm, from 1 to 50 nm, from 5 to 500 nm, from 25 to 500 nm, from 50 to 500 nm, from 100 to 500 nm, from 200 to 500 nm, from 300 to 500 nm, from 5 to 450 nm, or from 5 to 100 nm). In some examples, the plurality of silicon particles can have an average particle size of from 1 nm to 100 nm.

[0080] The graphene can comprise any suitable graphene consistent with the compositions, methods, and devices described herein. The graphene can, for example, comprise graphene oxide. In some examples, the graphene can comprise reduced graphene oxide.

[0081] Also disclosed herein are electrodes, such as anodes, comprising any of the composite materials disclosed herein. For example, the electrode can be stable, fast charging, or a combination thereof. In some examples, the electrode exhibits a capacity retention of 50% or more (e.g., 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more) for 20 cycles or more (e.g., 50 cycles or more, 100 cycles or more, or 150 cycles or more).

[0082] In some examples, the electrode exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C.

[0083] Also disclosed herein are electrochemical cells comprising any of the electrodes disclosed herein (e.g., comprising any of the composite materials disclosed herein). The electrochemical cell can further comprise other components, such as those known in the art for electrochemical cells (e.g., electrolyte, one or more additional electrodes, current collector, etc.).

[0084] Also disclosed herein are devices, such as batteries, comprising any of the electrodes disclosed herein (e.g., comprising any of the composite materials disclosed herein).

[0085] Also disclosed herein are batteries comprising any of the electrodes disclosed herein (e.g., comprising any of the composite materials disclosed herein). The battery can further comprise other components, such as those known in the art for batteries (e.g., electrolyte, one or more additional electrodes, current collector, etc.).

[0086] For example, the battery can be a lithium-ion battery. In some examples, the battery is rechargeable.

[0087] In some examples, the battery exhibits improved cycle life, improved stability, high-rate capabilities (e.g., fast-charging), improved performance, or a combination thereof.

[0088] In some examples, the battery exhibits a capacity retention of 50% or more (e.g., 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more) for 100 cycles or more (e.g., 150 cycles or more).

[0089] In some examples, the battery exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C.

[0090] Also disclosed herein are systems comprising one or more of any of the batteries disclosed herein. For example, the system can be an energy storage system.

[0091] Also disclosed herein are articles comprising one or more of any of the batteries disclosed herein. For example, the article can comprise a vehicle, an electronic device, or a combination thereof. Methods of Use

[0092] Also disclosed herein are methods of use of any of the compositions and / or devices disclosed herein.

[0093] For example, also disclosed herein are methods of use of any of the composite materials disclosed herein, any of the electrodes disclosed herein, any of the electrochemical cells disclosed herein, any of the devices disclosed herein, any of the batteries disclosed herein, any of the systems disclosed herein, any of the articles disclosed herein, or a combination thereof.

[0094] Methods of Making

[0095] Also disclosed herein are methods of making any of the compositions and / or devices disclosed herein.

[0096] For example, also disclosed herein are methods of making any of the composite materials disclosed herein. The methods can, for example, comprise contacting a first dispersion with a second dispersion to form a mixture; the first dispersion comprising the plurality of silicon particles dispersed in a first solvent; the second dispersion comprising graphene dispersed in a second solvent; and hydrothermally treating the mixture to thereby form the composite material.

[0097] In some examples, the methods can further comprise comprising forming the first dispersion by dispersing the plurality of silicon particles in the first solvent.

[0098] In some examples, the methods can further comprise forming the second dispersion by dispersing the graphene in the second solvent.

[0099] The first solvent and the second solvent can each independently comprise any suitable solvent, wherein the first solvent and the second solvent can be the same or different. The first solvent and the second solvent can, for example, each independently comprise water, ethylene glycol, polyethylene glycol, glycerol, alkane diol, ethanol, methanol, propanol, isopropanol, dimethyl sulfoxide (DMSO), acetonitrile, methylene chloride, or combinations thereof. In some examples, the first solvent and / or the second solvent comprises water (e.g., an aqueous solvent).

[0100] In some examples, the methods further comprise making the plurality of silicon particles.

[0101] In some examples, the methods further comprise making the graphene.

[0102] The contacting and / or dispersing can, for example, comprise agitation. Agitating can be accomplished, for example, by mechanical stirring, shaking, vortexing, sonication (e.g., bath sonication, probe sonication, ultrasonication), and the like, or combinations thereof. In some examples, contacting and / or dispersing can comprise sonication.

[0103] Hydrothermally treating the mixture can, for example, comprise heating the mixture at a temperature for an amount of time.

[0104] The temperature can, for example, be 150°C or more (e.g., 160°C or more, 170°C or more, 180°C or more, or 190°C or more). In some examples, the temperature can be 200°C or less (e.g., 190°C or less, 180°C or less, 170°C or less, or 160°C or less). The temperature can range from any of the minimum values described above to any of the maximum values described above. For example, the temperature can be from 150°C to 200°C (e.g., from 150°C to 175°C, from 175°C to 200°C, from 150°C to 160°C, from 160°C to 170°C, from 170°C to 180°C, from

[0105] 180°C to 190°C, from 190°C to 200°C, from 150°C to 190°C, from 150°C to 180°C, from

[0106] 150°C to 170°C, from 160°C to 200°C, from 170°C to 200°C, from 180°C to 200°C, from

[0107] 155°C to 195°C, from 160°C to 190°C, or from 170°C to 190°C).

[0108] The amount of time can, for example, be 4 hours or more (e.g., 5 hours or more, 6 hours or more, 7 hours or more, 8 hours or more, 9 hours or more, 10 hours or more, or 11 hours or more). In some examples, the amount of time can be 12 hours or less (e.g., 11 hours or less, 10 hours or less, 9 hours or less, 8 hours or less, 7 hours or less, 6 hours or less, or 5 hours or less). The amount of time can range from any of the minimum values described above to any of the maximum values described above. For example, the amount of time can be from 4 to 12 hours (e.g., from 4 to 8 hours, from 8 to 12 hours, from 4 to 6 hours, from 6 to 8 hours, from 8 to 10 hours, from 10 to 12 hours, from 4 to 10 hours, from 6 to 12 hours, from 8 to 12 hours, or from 5 to 11 hours).

[0109] In some examples, hydrothermally treating the mixture comprises heating the mixture at a temperature (e.g., from 150-200°C, such as 180°C) for an amount of time (e.g., from 4-12 hours, such as 6 hours). In some examples, hydrothermally treating the mixture comprises heating the mixture at a temperature from 150-200°C for an amount of time of from 4-12 hours. In some examples, hydrothermally treating the mixture comprises heating the mixture at a temperature of 180°C for an amount of time of 6 hours.

[0110] In some examples, the methods further comprise additional processing after the hydrothermal treatment to form the composite material. In some examples, the additional processing comprises grinding and / or drying.

[0111] A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

[0112] The examples below are intended to further illustrate certain aspects of the devices and methods described herein, and are not intended to limit the scope of the claims. EXAMPLES

[0113] The following examples are set forth below to illustrate the methods and results according to the disclosed subject matter. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative methods and results. These examples are not intended to exclude equivalents and variations of the present invention which are apparent to one skilled in the art.

[0114] Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. There are numerous variations and combinations of measurement conditions, e.g., component concentrations, temperatures, pressures and other measurement ranges and conditions that can be used to optimize the described process.

[0115] Example 1 - Chemically Modified Graphene and Silicon Composite Anodes for Fast- Charging Lithium-Ion Batteries

[0116] The exhaustion of fossil fuels and global warming leads to a lot of research efforts to develop eco-friendly energy storage systems. Lithium-ion batteries (LIBs) have attracted considerable attention, due to their high energy density and capacity, high operating voltage, and long cycle life, among other excellent charge-discharge performance characteristics.

[0117] Among various electrode materials, silicon (Si) is a promising candidate as an electrode material for next-generation Lithium-ion batteries due to its abundance (26.4% in earth crust), low cost, high theoretical gravimetric capacity of 4200 mA h / g (for Li uptake to the Li4.4Si stoichiometry), and low operating potential. However, the main problem of Si anodes is its significant volume expansion (e.g., -360%) during repeated charge-discharge cycles, resulting in unwanted particle pulverization and unstable solid-electrolyte interphase (SEI) layers at anodeelectrolyte interphase. The particle isolation of Si and reduced electrical contact between Si particles and / or between Si and a current collector degrade cycle life and increase cell impedance.

[0118] To address these issues, research is actively proceeding to prepare Si and carbon-based anode composites by blending Si particles with carbon nanostructures having high surface area and excellent electrical conductivity. Among the carbon-based materials, graphene, a two- dimensional hexagonal lattice structure composed of carbon atoms with sp2bonding is recognized potential anode materials for the next generation of Lithium-ion batteries to replace graphite due to high electrical conductivity, large surface area, and excellent mechanical and chemical stability. Recently, several papers reported that to effectively disperse Si particles and prevent the volume expansion of Si, Si / Graphene complexes as buffering materials for Lithium- ion batteries anodes, which lead to enhanced cycle life and performance.

[0119] Described herein is a Si and reduced graphene oxide (Si / G) nanocomposite with improved cycle life and high-rate capabilities (e.g., fast-charging) as anode materials for Lithium-ion batteries. The aqueous suspension of graphene oxide (GO) was produced by sonication of graphite oxide powder, which was produced using the Hummers method. While commercial Si nanopowder is not well dispersed in the aqueous solvent due to hydrophobic properties, GO is uniformly dispersed in water due to the hydrophilicity of abundant oxygen functional groups at the surface of GO. These two dispersions were mixed and hydrothermally treated at 180°C for 6 h to form Si / G nanocomposites, resulting in the uniform distribution of Si nanoparticles on reduced graphene oxide supports (Figure 1). During this hydrothermal process, some of oxygen functionalities of GO was removed forming reduced graphene oxide materials.

[0120] Scanning electron microscopy (SEM) images (Figure 2A-Figure 2D) of the prepared Si / G nanocomposites showed that the size of Si particles approximately < 100 nm are uniformly embedded between the wrinkled graphene supports.

[0121] In the X-ray diffraction (XRD) patterns (Figure 3), the main characteristic diffraction peaks of the Si / G nanocomposite at 28, 47, 56, 69, and 76° correspond to the crystalline Si nanoparticles (111), (220), (311), (400), and (331) planes, respectively. Additionally, the peak of G shows at 23°, corresponding to the interlayer spacing between graphene layers.

[0122] X-ray photoelectron spectroscopy (XPS) analysis (Figure 4A-Figure 4C) revealed surface information of Si / G nanocomposite. The survey spectra (Figure 4A) of Si / G nanocomposite suggests the presence of C, O, and Si elements with the intensity peak of O element reduced compared to C element, implying reduced graphene. On the other hand, Figure 4B shows the deconvoluted Si 2p spectrum of Si / G nanocomposites corresponding to metallic Si bonds at 99.7 eV of Si 2 / 23 / 2 and 100.4 eV of Si 2 >3 / I, silicon oxicarbide (Si-O-C) bond at 101.2 eV, and Si oxide bonds at 102.3, 103.7, 104.6, and 105.7 eV, respectively. From Figure 4C, deconvoluted O 15 spectrum of Si / G nanocomposite can be observed corresponding to C=O bond at 531.5 eV, Si-O-Si bond at 532. 9 eV, C-0 bond at 533.7 eV, and O-C=O bond at 534.5 eV.

[0123] The cycle performance and capacity retentions of the Si / G nanocomposite anode exhibited improved stability compared to the baseline Si anode at 150 cycles (Figure 5 A and Figure 5B). It can be seen that the capacity delivered after 100 cycles is 480.7 mA h / g for Si / G and 178.3 mA h / g for Si, which indicates that capacity retention of 65.5% for Si / G and 5.9% for Si, respectively.

[0124] To reduce anode degradation due to constant volume change, a specialized cycling protocol is used. The cycle performance applied to limited capacity protocol is presented in Figure 5C and Figure 5D, which show improved stability of Si / G nanocomposite anode compared to commercial Si anode. Si anode exhibited high initial capacity of 1417.5 mA h / g, but the specific capacities of Si anode declined dramatically after 20 cycles and poor stabilities from 50 to 300 cycles. Although the Si / G anode has a low initial capacity (550.4 mA h / g), it can be seen that the capacity is maintained up to 100 cycles. In addition, the limited charge applied capacity retention of Si / G anode, shows outstanding stability in the 100 cycles at 96.4%, while the Si anode only retained 10.3% of its original capacity. On the contrary, Si / G anode shows that up to 39.4% of its capacity is retained after 300 cycles.

[0125] Figure 6A displays the rate performance at various current densities for fast charge of Si / G nanocomposite anode. The currents applied were 0.05 C (0.2 A / g), 1 C (4 A / g), 3 C (6 A / g), and 5 C (21 A / g) for Si anode and 0.05 C (0.1 A / g), 1 C (2 A / g), 3 C (6 A / g), 5 C (9 A / g), 7 C (13 A / g), and 10 C (19 A / g) for Si / G anode. Si / G anode showed superior rate capabilities for fast charging (lithiation). In particular, the Si / G anode delivered high reversible capacities of 760.9. 581.3, 468.7, and 315.4 mA h / g, respectively, at 3 C, 5 C, 7 C, and 10 C-rates at 25 °C. By contrast, the capacity of Si anode decreased dramatically at 3 C, achieving only 10.1 mA h / g. The significant difference in fast charging performance between these two anodes suggests that graphene networks in Si / G anode provides fast electron and Li-ion transport pathways. Figure 6B and Figure 6C exhibits voltage profile plots at various current densities for Si and Si / G nanocomposite anodes during fast charging. It is shown that Si / G anode achieved better capacity from 3 C to 10 C when compared to Si anode.

[0126] Figure 7A-Figure 7D illustrates the voltage profiles and differential capacity (dO / d V) profiles for Si and Si / G anodes based on limited capacity cycling process. In Figure 7B, both electrodes exhibit similar lithiation d 2 / dK profiles at the 4th cycle. In both cases two notable peaks can be seen, representing the different stage of Si and Li alloying. However, as the cycle number increases for the Si anode, these two peaks gradually shift toward lower voltages and eventually disappear by the 50th cycle. This observation indicates that the lithiation process of Si anode is hindered as the cycle number increases, resulting in an overall decrease in capacity retention. Furthermore, a significant IR drop is evident in the lithiation voltage profile of the Si anode. The shifting of peaks and the increase in IR drop suggest that the Si anode experiences a significant increase in resistance, which led to decrease in capacity retention at higher cycle numbers. In contrast, Figure 7D shows that despite undergoing 50 cycles, the Si / G anode exhibits minimal changes to the voltage profile and d ) / dF curve. The relatively stable performance of Si / G anode indicates that the inclusion of graphene helped stabilized the large impedance growth of the Si anode over time.

[0127] This phenomenon is further supported by Figure 8A-Figure 8B, where the electrochemical impedance spectroscopy (EIS) Nyquist plot illustrates that Si / G anode experiences lower impedance growth overall compared to the Si anode after prolonged cycling.

[0128] EXEMPLARY ASPECTS

[0129] In view of the described compositions, devices, systems, and methods, herein below are described certain more particularly described aspects of the inventions. The particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0130] Example 1 : A composite material comprising: a plurality of particles comprising silicon (Si) (e.g., a plurality of silicon particles); and a graphene; wherein the plurality of particles comprising silicon are dispersed substantially uniformly on the graphene.

[0131] Example 2: The composite material of any example herein, particularly example 1, wherein the plurality of particles comprising silicon have an average particle size of from 1 nanometers (nm) to 500 nanometers (nm), such as from 1 nm to 100 nm.

[0132] Example 3 : The composite material of any example herein, particularly example 1 or example 2, wherein the graphene comprises graphene oxide.

[0133] Example 4: The composite material of any example herein, particularly examples 1-3, wherein the graphene comprises reduced graphene oxide.

[0134] Example 5: An electrode, such as an anode, comprising the composite material of any example herein, particularly examples 1-4.

[0135] Example 6: The electrode of any example herein, particularly example 5, wherein the electrode is stable, fast charging, or a combination thereof.

[0136] Example 7: The electrode of any example herein, particularly example 5 or example 6, wherein the electrode exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 20 cycles or more (e.g., 50 cycles or more, 100 cycles or more, or 150 cycles or more).

[0137] Example 8: The electrode of any example herein, particularly examples 5-7, wherein the electrode exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C. Example 9: An electrochemical cell comprising the electrode of any example herein, particularly examples 5-8.

[0138] Example 10: A device, such as a battery, comprising the electrode of any example herein, particularly examples 5-8.

[0139] Example 11 : A battery comprising the electrode of any example herein, particularly examples 5-8.

[0140] Example 12: The battery of any example herein, particularly example 11, wherein the battery is a lithium-ion battery.

[0141] Example 13: The battery of any example herein, particularly example 11 or example 12, wherein the battery is rechargeable.

[0142] Example 14: The battery of any example herein, particularly examples 11-13, wherein the battery exhibits improved cycle life, improved stability, high-rate capabilities (e.g., fastcharging), improved performance, or a combination thereof.

[0143] Example 15: The battery of any example herein, particularly examples 11-14, wherein the battery exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 100 cycles or more (e.g., 150 cycles or more).

[0144] Example 16: The battery of any example herein, particularly examples 11-15, wherein the battery exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3-10 C at 25°C.

[0145] Example 17: A system comprising one or more of the batteries of any example herein, particularly examples 11-16.

[0146] Example 18: The system of any example herein, particularly example 17, wherein the system is an energy storage system.

[0147] Example 19: An article comprising one or more of the batteries of any example herein, particularly examples 11-16.

[0148] Example 20: The article of any example herein, particularly example 19, wherein the article comprises a vehicle, an electronic device, or a combination thereof.

[0149] Example 21 : A method of use of the composite material of any example herein, particularly examples 1-4, the electrode of any example herein, particularly examples 5-8, the electrochemical cell of any example herein, particularly example 9, the device of any example herein, particularly example 10, the battery of any example herein, particularly examples 11-16, the system of any example herein, particularly examples 17-18, the article of any example herein, particularly examples 19-20, or a combination thereof.

[0150] Example 22: A method of making the composite material of any example herein, particularly examples 1-4.

[0151] Example 23 : The method of any example herein, particularly example 22, wherein the method comprises: contacting a first dispersion with a second dispersion to form a mixture; the first dispersion comprising the plurality of silicon particles dispersed in a first solvent; the second dispersion comprising graphene dispersed in a second solvent; and hydrothermally treating the mixture to thereby form the composite material.

[0152] Example 24: The method of any example herein, particularly example 23, further comprising forming the first dispersion by dispersing the plurality of silicon particles in the first solvent.

[0153] Example 25: The method of any example herein, particularly example 23 or example 24, further comprising forming the second dispersion by dispersing the graphene in the second solvent.

[0154] Example 26: The method of any example herein, particularly examples 23-25, wherein the first solvent and the second solvent are the same or different.

[0155] Example 27: The method of any example herein, particularly examples 23-26, wherein the first solvent and / or the second solvent is each independently an aqueous solvent.

[0156] Example 28: The method of any example herein, particularly examples 23-27, further comprising making the plurality of silicon particles.

[0157] Example 29: The method of any example herein, particularly examples 23-28, further comprising making the graphene.

[0158] Example 30: The method of any example herein, particularly examples 23-29, wherein the contacting and / or dispersing comprises agitation, such as sonication.

[0159] Example 31 : The method of any example herein, particularly examples 23-30, wherein hydrothermally treating the mixture comprises heating the mixture at a temperature (e.g., from 150-200°C, such as 180°C) for an amount of time (e.g., from 4-12 hours, such as 6 hours).

[0160] Example 32: The method of any example herein, particularly examples 23-31, further comprising additional processing after the hydrothermal treatment to form the composite material.

[0161] Example 33: The method of any example herein, particularly example 32, wherein the additional processing comprises grinding and / or drying. Other advantages which are obvious and which are inherent to the invention will be evident to one skilled in the art. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

[0162] The methods of the appended claims are not limited in scope by the specific methods described herein, which are intended as illustrations of a few aspects of the claims and any methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Further, while only certain representative method steps disclosed herein are specifically described, other combinations of the method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein or less, however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

Claims

CLAIMSWhat is claimed is:

1. A composite material comprising: a plurality of particles comprising silicon (Si) (e.g., a plurality of silicon particles); and a graphene; wherein the plurality of particles comprising silicon are dispersed substantially uniformly on the graphene.

2. The composite material of claim 1, wherein the plurality of particles comprising silicon have an average particle size of from 1 nanometers (nm) to 500 nanometers (nm), such as from 1 nm to 100 nm.

3. The composite material of claim 1 or claim 2, wherein the graphene comprises graphene oxide.

4. The composite material of any one of claims 1-3, wherein the graphene comprises reduced graphene oxide.

5. An electrode, such as an anode, comprising the composite material of any one of claims 1-4.

6. The electrode of claim 5, wherein the electrode is stable, fast charging, or a combination thereof.

7. The electrode of claim 5 or claim 6, wherein the electrode exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 20 cycles or more (e.g., 50 cycles or more, 100 cycles or more, or 150 cycles or more).

8. The electrode of any one of claims 5-7, wherein the electrode exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3- 10 C at 25°C.

9. An electrochemical cell comprising the electrode of any one of claims 5-8.

10. A device, such as a battery, comprising the electrode of any one of claims 5-8.

11. A battery comprising the electrode of any one of claims 5-8.

12. The battery of claim 11, wherein the battery is a lithium-ion battery.

13. The battery of claim 11 or claim 12, wherein the battery is rechargeable.

14. The battery of any one of claims 11-13, wherein the battery exhibits improved cycle life, improved stability, high-rate capabilities (e.g., fast-charging), improved performance, or a combination thereof.

15. The battery of any one of claims 11-14, wherein the battery exhibits a capacity retention of 50% or more (e.g., 60% or more, 70% or more, 80% or more, or 90% or more) for 100 cycles or more (e.g., 150 cycles or more).

16. The battery of any one of claims 11-15, wherein the battery exhibits a capacity rage of 250 mA h / g or more (e.g., 300 mA h / g or more, 350 mA h / g or more, 400 mA h / g or more, 450 mA h / g or more, 500 mA h / g or more, 550 mA h / g or more, 600 mA h / g or more, 650 mA h / g or more, 700 mA h / g or more, 750 mA h / g or more, or 800 mA h / g or more) at a current of from 3- 10 C at 25°C.

17. A system comprising one or more of the batteries of any one of claims 11-16.

18. The system of claim 17, wherein the system is an energy storage system.

19. An article comprising one or more of the batteries of any one of claims 11-16.

20. The article of claim 19, wherein the article comprises a vehicle, an electronic device, or a combination thereof.

21. A method of use of the composite material of any one of claims 1-4, the electrode of any one of claims 5-8, the electrochemical cell of claim 9, the device of claim 10, the battery of any one of claims 11-16, the system of claims 17-18, the article of claims 19-20, or a combination thereof.

22. A method of making the composite material of any one of claims 1-4.

23. The method of claim 22, wherein the method comprises: contacting a first dispersion with a second dispersion to form a mixture; the first dispersion comprising the plurality of silicon particles dispersed in a first solvent; the second dispersion comprising graphene dispersed in a second solvent; and hydrothermally treating the mixture to thereby form the composite material.

24. The method of claim 23, further comprising forming the first dispersion by dispersing the plurality of silicon particles in the first solvent.

25. The method of claim 23 or claim 24, further comprising forming the second dispersion by dispersing the graphene in the second solvent.

26. The method of any one of claims 23-25, wherein the first solvent and the second solvent are the same or different.

27. The method of any one of claims 23-26, wherein the first solvent and / or the second solvent is each independently an aqueous solvent.

28. The method of any one of claims 23-27, further comprising making the plurality of silicon particles.

29. The method of any one of claims 23-28, further comprising making the graphene.

30. The method of any one of claims 23-29, wherein the contacting and / or dispersing comprises agitation, such as sonication.

31. The method of any one of claims 23-30, wherein hydrothermally treating the mixture comprises heating the mixture at a temperature (e.g., from 150-200°C, such as 180°C) for an amount of time (e.g., from 4-12 hours, such as 6 hours).

32. The method of any one of claims 23-31, further comprising additional processing after the hydrothermal treatment to form the composite material.

33. The method of claim 32, wherein the additional processing comprises grinding and / or drying.

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