Novel metal-silicon alloy-carbon composites, electrodes, and devices

Abstract

The present disclosure relates to particulate lithium-silicon alloy-carbon composite materials and processes for their manufacture, as well as corresponding devices and their corresponding manufacturing processes.

Description

[Technical field]

[0001] The present disclosure relates to novel composites containing metals, in particular, novel composites containing particles containing group 14 elements, e.g., carbon and silicon, where the silicon is composed of various domains, such as elemental silicon, silicon-metal alloys, and combinations thereof. Optionally, the composite may also contain domains of alloyed metals in non-alloyed form. The metals contained in the metal-silicon alloy domains may be aluminum, germanium, tin, lithium, or combinations thereof. In a preferred embodiment, the metal is lithium. These materials are produced by a novel process that results in the introduction of silicon, lithium-silicon alloys, and combinations thereof into the pores of the porous carbon scaffold particles. Optionally, the metals, particularly lithium, may contain non-alloyed domains, e.g., metal domains. The porous carbon scaffold particles may be produced from a variety of precursors, as known in the art. Such carbon precursors include, but are not limited to, cellulose, lignin, lignocellulosic materials, sugars and polyols, organic acids, phenolic compounds, crosslinkers, and amine compounds, and combinations thereof. The metal alloyed with silicon in the porous scaffold may be provided in metallic form. Alternatively, a metal salt or other metal-containing species may serve as a precursor for the metal in the metal-silicon alloy-carbon composite. Suitable porous scaffolds include, but are not limited to, porous carbon scaffolds, such as carbons having a pore volume of micropores (less than 2 nm), mesopores (2-50 nm), and / or macropores (greater than 50 nm). [Background technology]

[0002] Lithium is a potentially useful anode material due to its high specific capacity (3900 mAh / g), low redox potential (-3.04 V), and ability to provide the entire battery lithium supply, for example enabling battery chemistries with lithium-free cathode materials. However, lithium metal anodes have not yet reached practical application due to their low coulombic efficiency (CE) and the growth of lithium dendrites during lithium dissolution / precipitation. Such lithium striping and plating degradation reduces battery performance, resulting in limited cycle life and creating serious safety concerns that prevent the practical application of batteries using lithium metal anodes.

[0003] To address these issues, there has been limited progress in "pre-lithiation," also referred to in some literature as "pre-doping of lithium ions," to achieve the addition of lithium to the active lithium content of lithium-ion batteries (LIBs) prior to the operation of the battery cell (F Holtstiege, P Barmann, R Nolle, M Winter, and T Placke, "Pre-Lithiation Strategies for Rechargeable Energy Storage Technologies: Concepts, Promises and Challenges," Batteries 2018, 4(1), 4). Such approaches can provide limited improvements, for example, in increasing reversible capacity and, consequently, higher gravimetric or volumetric energy density. It is important to note in the field that pre-lithiation is supported on devices, particularly anode electrodes that include silicon-containing anode active materials. Despite some progress, significant hurdles remain for the commercial deployment of pre-lithiation in terms of rising battery costs and increasing complexity of battery manufacturing, thus making the scale-up of pre-lithiation to battery manufacturing difficult. Fundamentally, electrode-level prelithiation presents commercialization hurdles in that it would require battery manufacturers to scale up and install additional capital equipment.

[0004] The present disclosure solves these problems by providing alloying metals, particularly lithium, into particles that include silicon and porous carbon scaffolds. The particles are particulate; in a preferred embodiment, the resulting lithium-silicon alloy-carbon composite particles are stable under ambient conditions or, alternatively, under conditions already practiced for commercial electrode (e.g., cathode) and battery manufacturing. Thus, the novel lithium-silicon alloy-carbon composite particulate material disclosed herein can be dropped into existing commercial processes, thus providing easy scale-up and adoption into existing electrode and battery manufacturing lines to facilitate commercial utility. Summary of the Invention

[0005] The present disclosure relates to novel metal-group 14 composite material compositions and methods of making same, as well as electrodes and batteries comprising same. The metal-group 14 composite material may be a metal-silicon-carbon composite, such as a metal-silicon alloy-carbon composite material, such as a lithium-silicon alloy-carbon composite material. The material may be a particulate, such as produced by the creation of a porous carbon scaffold particle, followed by impregnation of silicon, followed by impregnation of a metal, particularly lithium, into one or more pores of the porous carbon scaffold particle. For purposes of the present disclosure, impregnation of lithium may be achieved by a variety of approaches, including, but not limited to, melt intrusion, electrochemical deposition, electroreduction, chemical reduction, lithium evaporation, or combinations thereof. In certain embodiments, the lithium is present in the form of an alloy with silicon located within one or more pores of the porous carbon scaffold. In some embodiments, the metal-group 14 composite particle may include an outer layer composed of carbon or other inorganic species. In some embodiments, the metal-lithium alloy-carbon composite is produced by heat treatment of a mixture of carbon and lithium precursor materials.

[0006] The impregnated lithium domain size can vary, for example, the impregnated lithium domains can reflect the size of the silicon located within the pores of the porous carbon scaffold, and can range from, for example, 0.5 nm, or 0.5 nm to 1 nm, or less than 1 nm, or 1 nm to 2 nm, or less than 2 nm, or 2 nm to 4 nm, or less than 4 nm, or less than 5 nm, or less than 10 nm, or 2 nm to 50 nm, or less than 50 nm, or more than 50 nm, or combinations thereof. The porous carbon scaffold can be a particulate porous carbon, with an average particle size ranging from 100 nm to 100 μm.

[0007] An important advantage of impregnating lithium into silicon within the pores of a porous carbon scaffold is that carbon provides nucleation sites for impregnating lithium, as well as defining the maximum particle shape and size.An additional advantage of impregnating lithium into silicon within the pores of a porous carbon scaffold is that the composite particles may retain residual intraparticle voids, which may provide additional electrochemical advantages to the lithium-silicon alloy-carbon composite anode material as disclosed herein.Another advantage of confining the growth of lithium in the anode within a nanoporous structure is that the effects of lithium dendrite formation or plating are reduced.In addition, the metal-lithium alloy-carbon composite structure promotes nanosizing of lithium in the anode and retains lithium as an amorphous phase.

[0008] Such properties result in improved first cycle efficiency (FCE), resulting in lower demands on the cathode and thus higher gravimetric and volumetric battery energy density, improved coulombic efficiency (CE), and improved cycling stability in combination with high charge / discharge rates, especially in combination with the proximity of lithium in silicon within the conductive carbon scaffold.

[0009] The lithium-silicon alloy-carbon composite material as disclosed herein has utility as a battery material, for example as an anode active material for conventional or solid-state lithium ion batteries. The lithium-silicon alloy-carbon composite material as disclosed herein has utility as a battery material, for example as an anode material for lithium silicon batteries. [Brief description of the drawings]

[0010] [Figure 1] X-ray diffraction patterns of various composite materials. [Diagram 2] X-ray diffraction pattern of lithium alloyed silicon-carbon composite. [Diagram 3] Electrochemical charge-discharge cycling stability plots of various composite materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the following description, certain specific details are set forth to provide a thorough understanding of various embodiments. However, those skilled in the art will appreciate that the present disclosure may be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. Unless otherwise required by context, throughout this specification and the claims that follow, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be construed in an open, inclusive sense, i.e., "including, but not limited to." Additionally, the headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed disclosure.

[0012] Throughout this specification, reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification does not necessarily all refer to the same embodiment. Moreover, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Also, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed in the sense of including "and / or" unless otherwise specified.

[0013] A. Porous Scaffold Materials For the purposes of the embodiments of the present disclosure, a porous scaffold impregnated with lithium may be used. In the present disclosure, the porous scaffold may comprise a variety of materials. In some embodiments, the porous scaffold material comprises primarily carbon, such as hard carbon. In other embodiments, other allotropes of carbon are also envisioned, such as graphite, amorphous carbon, diamond, C60, carbon nanotubes (e.g., single-walled and / or multi-walled), graphene, and / or carbon fibers. The introduction of porosity into the carbon material may be achieved by various means. For example, porosity in the carbon material may be achieved by adjusting the polymer precursor and / or processing conditions for making the porous carbon material, which will be described in detail in the following section.

[0014] In other embodiments, the porous scaffold comprises a polymeric material. For purposes of this disclosure, it is contemplated that a wide variety of polymers have utility in various embodiments, including, but not limited to, inorganic polymers, organic polymers, and additional polymers. Examples of organic polymers include, but are not limited to, sulfur-containing polymers such as polysulfides, polysulfones, low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), nylon, nylon 6, nylon 6,6, Teflon (polytetrafluoroethylene), thermoplastic polyurethane (TPU), polyurea, poly(lactide), poly(glycolide) and combinations thereof, phenolic resins, polyamides, polyaramids, polyethylene terephthalate, polychloroprene, polyacrylonitrile, polyaniline, polyimides, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PDOT:PSS), and other polymers known in the art. Organic polymers may be synthetic or natural in origin. In some embodiments, the polymer is a polysaccharide, such as sucrose, starch, cellulose, cellobiose, amylose, amylopectin, gum arabic, lignin, etc. In some embodiments, the polysaccharide is derived from the caramelization of mono- or oligomeric sugars, such as fructose, glucose, sucrose, maltose, raffinose, etc.

[0015] In certain embodiments, the porous scaffold polymeric material comprises a coordination polymer. The coordination polymer in the present disclosure includes, but is not limited to, metal-organic frameworks (MOFs). The manufacturing techniques of MOFs and exemplary species of MOFs are known and described in the art (The Chemistry and Applications of Metal-Organic Frameworks, Hiroyasu Furukawa et al. Science 341, (2013); DOI: 10.1126 / science.1230444). Examples of MOFs in the present disclosure include, but are not limited to, Basolite™ materials and zeolitic imidazolate frameworks (ZIFs).

[0016] Concomitant with the myriad of different polymers that are envisioned to have the potential to provide a porous substrate, various processing approaches are envisioned in various embodiments to achieve said porosity. In this disclosure, the general methods for imparting porosity to various materials are numerous as known in the art, including, but not limited to, emulsification, micelle generation, gasification, dissolution followed by solvent removal (e.g., freeze drying), axial pressing and sintering, gravity sintering, powder rolling and sintering, isostatic pressing and sintering, metal spraying, metal coating and sintering, metal injection molding and sintering, etc. Other approaches to making porous polymeric materials are also envisioned, including the creation of porous gels such as freeze-dried gels, aerogels, etc.

[0017] In certain embodiments, the porous scaffold material comprises a porous ceramic material. In certain embodiments, the porous scaffold material comprises a porous ceramic foam. In the present disclosure, general methods for imparting porosity to ceramic materials are varied as known in the art, including, but not limited to, creation of porous. In the present disclosure, general methods and materials suitable for constructing porous ceramics include, but are not limited to, porous aluminum oxide, porous zirconia-reinforced alumina, porous partially stabilized zirconia, porous alumina, porous sintered silicon carbide, sintered silicon nitride, porous cordierite, porous zirconium oxide, clay-bonded silicon carbide, and the like.

[0018] In certain embodiments, the porous material comprises a porous metal. Suitable metals in this regard include, but are not limited to, porous aluminum, porous steel, porous nickel, porous inconcel, porous hastelloy, porous titanium, porous copper, porous brass, porous gold, porous silver, porous germanium, and other metals that can be formed into a porous structure, as known in the art. In some embodiments, the porous scaffold material comprises a porous metal foam. Types of metals and associated manufacturing methods are known in the art. Such methods include, but are not limited to, casting (including foaming, infiltration, lost foam casting), deposition (chemical and physical), gas eutectic formation, and powder metallurgy techniques (powder sintering, molding in the presence of foaming agents, fiber metallurgy, etc.).

[0019] B. Porous Carbon Scaffold Materials

[0020] Methods for preparing porous carbon materials from polymer precursors are known in the art. For example, methods for preparing carbon materials are described in U.S. Patent Nos. 7,723,262, 8,293,818, 8,404,384, 8,654,507, 8,916,296, 9,269,502, 10,590,277, and U.S. Patent Application No. 16 / 745,197, the entire disclosures of which are incorporated herein by reference in their entirety for all purposes.

[0021] Thus, in one embodiment, the present disclosure provides a method for preparing any of the carbon materials or polymer gels described above. The carbon materials can be synthesized through pyrolysis of any of the single precursors, such as saccharide materials, such as sucrose, fructose, glucose, dextrin, maltodextrin, starch, amylopectin, cellulose, amylose, lignin, gum arabic, and other saccharides known in the art, and combinations thereof. Alternatively, the carbon materials can be synthesized by pyrolysis of composite resins formed using a sol-gel process, using polymer precursors, such as phenol, resorcinol, bisphenol A, urea, melamine, and other suitable compounds known in the art, and combinations thereof, in a suitable solvent, such as water, ethanol, methanol, and other solvents known in the art, and combinations thereof, with crosslinkers, such as formaldehyde, hexamethylenetetramine, furfural, and other crosslinkers known in the art, and combinations thereof. The resins can be acidic or basic and can include a catalyst. The catalyst may be volatile or non-volatile. The pyrolysis temperature and reaction time may be varied as known in the art.

[0022] In some embodiments, the method involves the preparation of a polymer gel by a sol-gel process, a condensation process, or a crosslinking process, comprising a monomer precursor and a crosslinker, two pre-existing polymers and a crosslinker, or one polymer and a crosslinker, followed by pyrolysis of the polymer gel. The polymer gel may be dried (e.g., freeze-dried) prior to pyrolysis, but drying is not required.

[0023] The desired carbon properties can be obtained from a variety of polymer chemistries, provided that the polymerization reaction produces a resin / polymer with the required carbon backbone. The various polymer families include novolacs, resoles, acrylates, styrenes, urethanes, rubbers (neoprene, styrene-butadiene, etc.), nylons, etc. Preparation of any of these polymer resins can be done by many different processes, including sol-gel, emulsion / suspension, solid state, solution state, melt state, etc., polymerization and crosslinking processes.

[0024] In some embodiments, the reactant comprises phosphorus. In other particular embodiments, the phosphorus is in the form of phosphoric acid. In other particular embodiments, the phosphorus can be in the form of a salt, where the anion of the salt comprises one or more of phosphate, phosphite, phosphide, hydrogen phosphate, dihydrogen phosphate, hexafluorophosphate, hypophosphite, polyphosphate, or pyrophosphate, or a combination thereof. In other particular embodiments, the phosphorus can be in the form of a salt, where the cation of the salt comprises one or more of phosphonium ions. The non-phosphate-containing anion or cation pair in any of the above embodiments can be selected from those known and described in the art. In the present disclosure, exemplary cations paired with phosphate-containing anions include, but are not limited to, ammonium, tetraethylammonium, and tetramethylammonium. In the present disclosure, exemplary anions paired with phosphate-containing cations include, but are not limited to, carbonate, bicarbonate, and acetate.

[0025] In some embodiments, the reactant comprises sulfur. In other particular embodiments, the sulfur is in the form of sulfuric acid. In other particular embodiments, the sulfur may be in the form of a salt, the anion of the salt comprising one or more of sulfate, sulfite, bisulfite, hyposulfite, sulfonium, S-methylmethionine, thiocarbonate, thiocyanate, thiophosphate, thiosilicate, or trimethylsulfonium, or combinations thereof.

[0026] In some embodiments, the catalyst comprises a basic volatilization catalyst. For example, in one embodiment, the basic volatilization catalyst comprises ammonium carbonate, ammonium bicarbonate, ammonium acetate, ammonium hydroxide, or a combination thereof. In a further embodiment, the basic volatilization catalyst is ammonium carbonate. In another further embodiment, the basic volatilization catalyst is ammonium acetate.

[0027] In yet other embodiments, the method includes admixing an acid. In certain embodiments, the acid is solid at room temperature and pressure. In some embodiments, the acid is liquid at room temperature and pressure. In some embodiments, the acid is liquid at room temperature and pressure and does not provide for dissolution of one or more of the other polymer precursors.

[0028] In certain embodiments, the polymer precursor components are blended together and then held at a sufficient time and temperature to achieve polymerization. One or more of the polymer precursor components may have a particle size of less than about 20 mm, such as less than 10 mm, such as less than 7 mm, such as less than 5 mm, such as less than 2 mm, such as less than 1 mm, such as less than 100 microns, such as less than 10 microns. In some embodiments, the particle size of one or more of the polymer precursor components is reduced during the blending process.

[0029] Mixing of one or more polymer precursor components in the absence of a solvent can be accomplished by methods described in the art, such as ball milling, jet milling, Fritsch milling, planetary mixing, and other mixing methods for mixing or blending solid particles while controlling process conditions (e.g., temperature). The mixing or blending process can be accomplished before, during, and / or after incubation (or a combination thereof) at the reaction temperature.

[0030] The reaction parameters include aging the blend mixture at a temperature and time sufficient for one or more polymer precursors to react with each other to form a polymer. In this regard, suitable aging temperatures range from about room temperature to a temperature at or near the melting point of one or more polymer precursors. In some embodiments, suitable aging temperatures range from about room temperature to a temperature at or near the glass transition temperature of one or more polymer precursors. For example, in some embodiments, the solventless mixture is aged at a temperature of about 20°C to about 600°C, such as about 20°C to about 500°C, such as about 20°C to about 400°C, such as about 20°C to about 300°C, such as about 20°C to about 200°C. In certain embodiments, the solventless mixture is aged at a temperature of about 50°C to about 250°C.

[0031] The reaction time is generally sufficient for the polymer precursors to react to form a polymer, for example, the mixture may be aged for anywhere from 1 hour to 48 hours, or more or less, depending on the desired result. Exemplary embodiments include aging for a period of about 2 hours to about 48 hours, for example, in some embodiments aging comprises about 12 hours, and in other embodiments aging comprises about 4 to 8 hours (e.g., about 6 hours).

[0032] In certain embodiments, electrochemical modifiers are incorporated during the polymerization process described above. For example, in some embodiments, electrochemical modifiers in the form of metal particles, metal pastes, metal salts, metal oxides, or molten metals may be dissolved or suspended in the mixture from which the gel resin is produced.

[0033] Exemplary electrochemical modifiers for producing composite materials may fall into one or more of the following chemical classes: In some embodiments, the electrochemical modifier is a lithium salt, including, but not limited to, lithium fluoride, lithium chloride, lithium carbonate, lithium hydroxide, lithium benzoate, lithium bromide, lithium formate, lithium peroxide, lithium hexafluorophosphate, lithium iodate, lithium perchlorate, lithium phosphate, lithium sulfate, lithium tetraborate, lithium tetrafluoroborate, and combinations thereof.

[0034] In certain embodiments, the electrochemical modifier comprises a metal, and exemplary species include, but are not limited to, aluminum isopropoxide, manganese acetate, nickel acetate, iron acetate, tin chloride, silicon chloride, and combinations thereof. In certain embodiments, the electrochemical modifier is a phosphate compound, and exemplary species include, but are not limited to, phytic acid, phosphoric acid, ammonium dihydrogen phosphate, and combinations thereof. In certain embodiments, the electrochemical modifier comprises silicon, and exemplary species include, but are not limited to, silicon powder, silicon nanotubes, polycrystalline silicon, nanocrystalline silicon, amorphous silicon, porous silicon, nanosized silicon, nanofeatured silicon, nanosized and nanofeatured silicon, silysine, black silicon, and combinations thereof.

[0035] Electrochemical modifiers can be combined with various polymer systems either by physical mixing or by chemical reaction with latent (or secondary) polymer functionality. Examples of latent polymer functionality include, but are not limited to, epoxide groups, unsaturation (double and triple bonds), acid groups, alcohol groups, amine groups, basic groups, etc. Crosslinking through latent functional groups can occur through heteroatoms (e.g., sulfur vulcanization, phosphoric acid acid / base / ring-opening reactions), reactions with organic acids or organic bases (as discussed above), coordination to transition metals (including, but not limited to, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ag, Au), ring-opening or ring-closing reactions (rotaxanes, spiro compounds, etc.).

[0036] The electrochemical modifier may be added to the polymer system by physical blending, including, but not limited to, melt blending of polymers and / or copolymers, inclusion of discrete particles, chemical vapor deposition of the electrochemical modifier, and co-precipitation of the electrochemical modifier with the base polymeric material.

[0037] In some examples, the electrochemical modifier may be added via a metal salt solid, solution or suspension. The metal salt solid, solution or suspension may include an acid and / or alcohol to improve the solubility of the metal salt. In yet another variation, the polymer gel (either before or after an optional drying step) is contacted with a paste containing the electrochemical modifier. In yet another variation, the polymer gel (either before or after an optional drying step) is contacted with a metal or metal oxide sol containing the desired electrochemical modifier.

[0038] In addition to the electrochemical modifiers exemplified above, the composite material may include one or more additional forms (i.e., allotropes) of carbon. In this regard, it has been found that including various allotropes of carbon, such as graphite, amorphous carbon, conductive carbon, carbon black, diamond, C60, carbon nanotubes (e.g., single-walled and / or multi-walled), graphene, and / or carbon fibers, in the composite material is effective for optimizing the electrochemical properties of the composite material. Various allotropes of carbon can be incorporated into the carbon material at any stage of the preparation process described herein. For example, during the solution stage, during the gelation stage, during the curing stage, during the pyrolysis stage, during the grinding stage, or after grinding. In some embodiments, the second carbon form is incorporated into the composite material by adding the second carbon form before or during the polymerization of the polymer gel, as described in more detail herein. The polymerized polymer gel containing the second carbon form is then processed according to the general techniques described herein to obtain a carbon material containing the second allotrope of carbon.

[0039] In other embodiments, the polymer precursor in the low-solvent or essentially solvent-free reaction mixture is a urea or amine-containing compound. For example, in some embodiments, the polymer precursor is urea, melamine, hexamethylenetetramine (HMT), or a combination thereof. Other embodiments include polymer precursors selected from other activated carbonyl compounds, such as isocyanates or acid halides.

[0040] Some embodiments of the method of the present disclosure include the preparation of low-solvent or solvent-free polymer gels (and carbon materials) containing electrochemical modifiers. Such electrochemical modifiers include, but are not limited to, nitrogen, silicon, and sulfur. In other embodiments, the electrochemical modifiers include fluorine, iron, tin, silicon, nickel, aluminum, zinc, or manganese. The electrochemical modifiers can be included in any step of the preparation procedure. For example, the electrochemical modifiers can be incorporated into the mixture, the polymer phase, or the continuous phase.

[0041] Porous carbon materials can be achieved by pyrolysis of polymers made from precursor materials such as those described above. In some embodiments, the porous carbon materials include amorphous activated carbons made by pyrolysis, physical or chemical activation, or a combination thereof, either in a single process step or in successive process steps.

[0042] The temperature and time of pyrolysis can vary, for example, the time can vary from 1 minute to 10 minutes, 10 minutes to 30 minutes, 30 minutes to 1 hour, 1 hour to 2 hours, 2 hours to 4 hours, 4 hours to 24 hours. The temperature can vary, for example, the pyrolysis temperature can be 200°C to 300°C, 250°C to 350°C, 350°C to 450°C, 450°C to 550°C, 540°C to 650°C, 650°C to 750°C, 750°C to 850°C, 850°C to 950°C, 950°C to 1050°C, 1050°C to 1150°C, 1150°C to 1250°C. In some embodiments, the pyrolysis temperature is 650°C to 1100°C. The pyrolysis can be accomplished in an inert gas, such as nitrogen, or argon.

[0043] In some embodiments, alternative gases are used to further achieve carbon activation. In certain embodiments, pyrolysis and activation are combined. Suitable gases for achieving carbon activation include, but are not limited to, carbon dioxide, carbon monoxide, water (steam), air, oxygen, and further combinations thereof. The temperature and time of activation can vary, for example, the time can vary from 1 minute to 10 minutes, 10 minutes to 30 minutes, 30 minutes to 1 hour, 1 hour to 2 hours, 2 hours to 4 hours, 4 hours to 24 hours. The temperature can vary, for example, pyrolysis temperature can be 200°C to 300°C, 250°C to 350°C, 350°C to 450°C, 450°C to 550°C, 540°C to 650°C, 650°C to 750°C, 750°C to 850°C, 850°C to 950°C, 950°C to 1050°C, 1050°C to 1150°C, 1150°C to 1250°C. In some embodiments, the temperature for the combined pyrolysis and activation is between 650°C and 1100°C.

[0044] In some embodiments, a combination of pyrolysis and activation is performed to prepare a porous carbon scaffold. In such embodiments, the process gas may remain the same during the process, or the composition of the process gas may change during the process. In some embodiments, the addition of an activation gas, such as CO2, water vapor, or a combination thereof, is added to the process gas after a sufficient temperature and time to allow pyrolysis of the solid carbon precursor.

[0045] Suitable gases for achieving carbon activation include, but are not limited to, carbon dioxide, carbon monoxide, water (steam), air, oxygen, and further combinations thereof. Activation temperature and time can vary, for example, time can vary from 1 minute to 10 minutes, 10 minutes to 30 minutes, 30 minutes to 1 hour, 1 hour to 2 hours, 2 hours to 4 hours, 4 hours to 24 hours. Temperature can vary, for example, pyrolysis temperature can vary from 200°C to 300°C, 250°C to 350°C, 350°C to 450°C, 450°C to 550°C, 540°C to 650°C, 650°C to 750°C, 750°C to 850°C, 850°C to 950°C, 950°C to 1050°C, 1050°C to 1150°C, 1150°C to 1250°C. In some embodiments, activation temperature varies from 650°C to 1100°C.

[0046] Either before pyrolysis and / or after pyrolysis and / or after activation, the carbon can be subjected to particle size reduction. Particle size reduction can be achieved by various techniques known in the art, for example, by jet milling in the presence of various gases, including air, nitrogen, argon, helium, supercritical steam, and other gases known in the art. Particle size reduction methods such as grinding, ball milling, jet milling, water jet milling, and other approaches known in the art are also contemplated. The resulting porous carbon particles are referred to herein interchangeably as porous carbon scaffolds and porous carbon frameworks.

[0047] The porous carbon scaffold may be in the form of particles. Particle size and particle size distribution may be measured by various techniques known in the art and described based on fractional volume. In this regard, the Dv50 of the carbon scaffold may be between 10 nm and 10 mm, such as between 100 nm and 1 mm, such as between 1 μm and 100 μm, such as between 2 μm and 50 μm, such as between 3 μm and 30 μm, such as between 4 μm and 20 μm, such as between 5 μm and 10 μm. In certain embodiments, the Dv50 is less than 1 mm, such as less than 100 μm, such as less than 50 μm, such as less than 30 μm, such as less than 20 μm, such as less than 10 μm, such as less than 8 μm, such as less than 5 μm, such as less than 3 μm, such as less than 1 μm. In certain embodiments, Dv100 is less than 1 mm, such as less than 100 μm, such as less than 50 μm, such as less than 30 μm, such as less than 20 μm, such as less than 10 μm, such as less than 8 μm, such as less than 5 μm, such as less than 3 μm, such as less than 1 μm. In certain embodiments, Dv99 is less than 1 mm, such as less than 100 μm, such as less than 50 μm, such as less than 30 μm, such as less than 20 μm, such as less than 10 μm, such as less than 8 μm, such as less than 5 μm, such as less than 3 μm, such as less than 1 μm. In certain embodiments, Dv90 is less than 1 mm, such as less than 100 μm, such as less than 50 μm, such as less than 30 μm, such as less than 20 μm, such as less than 10 μm, such as less than 8 μm, such as less than 5 μm, such as less than 3 μm, such as less than 1 μm. In certain embodiments, Dv0 is, for example, greater than 10 nm, such as greater than 100 nm, such as greater than 500 nm, such as greater than 1 μm, such as greater than 2 μm, such as greater than 5 μm, such as greater than 10 μm. In certain embodiments, Dv1 is greater than 10 nm, such as greater than 100 nm, such as greater than 500 nm, such as greater than 1 μm, such as greater than 2 μm, such as greater than 5 μm, such as greater than 10 μm. In certain embodiments, Dv10 is greater than 10 nm, such as greater than 100 nm, such as greater than 500 nm, such as greater than 1 μm, such as greater than 2 μm, such as greater than 5 μm, such as greater than 10 μm.

[0048] In some embodiments, the surface area of ​​the porous carbon scaffold is greater than or equal to 400 m 2 / g, e.g. 500m 2 / g, e.g. 750m 2 / g, e.g. 1000m 2 / g, e.g. 1250m 2 / g, e.g. 1500m 2 / g, e.g. 1750m 2 / g, e.g. 2000m 2 / g, e.g. 2500m 2 / g, e.g. 3000m 2 In other embodiments, the surface area of ​​the porous carbon scaffold can be greater than 500 m / g. 2 In some embodiments, the surface area of ​​the porous carbon scaffold can be less than 200-500 m / g. 2 In some embodiments, the surface area of ​​the porous carbon scaffold is between 100 and 200 m 2 / g. In some embodiments, the surface area of ​​the porous carbon scaffold is 50 m 2 / g~100m 2 In some embodiments, the surface area of ​​the porous carbon scaffold is 10 m 2 / g~50m 2 In some embodiments, the surface area of ​​the porous carbon scaffold is 10 m 2 / g.

[0049] In some embodiments, the pore volume of the porous carbon scaffold is less than or equal to 0.4 cm 3 / g, e.g. 0.5 cm 3 / g, e.g. 0.6 cm 3 / g, e.g. 0.7 cm 3 / g, e.g. 0.8 cm 3 / g, e.g. 0.9 cm 3 / g, e.g., 1.0 cm 3 / g, e.g. 1.1 cm 3 / g, e.g. 1.2 cm 3 / g, e.g. 1.4cm 3 / g, e.g. 1.6 cm 3 / g, e.g. 1.8 cm 3 / g, e.g., 2.0 cm 3In other embodiments, the pore volume of the porous carbon scaffold is greater than 0.5 cm 3 Less than, for example, 0.1 cm 3 / g~0.5cm 3 In other embodiments, the pore volume of the porous carbon scaffold is less than 0.01 cm 3 / g~0.1cm 3 / g.

[0050] In some other embodiments, the porous carbon scaffold has a thickness of 0.2 to 2.0 cm 3 In certain embodiments, the carbon is an amorphous activated carbon having a pore volume of 0.4 to 1.5 cm. 3 In certain embodiments, the carbon is an amorphous activated carbon having a pore volume of 0.5 to 1.2 cm. 3 In certain embodiments, the carbon is an activated carbon having a pore volume of 0.6 to 1.0 cm. 3 / g of pore volume.

[0051] In other embodiments, the porous carbon scaffold has a density of 1.0 g / cm 3 Less than, for example, 0.8 g / cm 3 Less than, for example, 0.6 g / cm 3 Less than, for example, 0.5 g / cm 3 , e.g. 0.4g / cm 3 Less than, for example, 0.3 g / cm 3 Less than, for example, 0.2 g / cm 3 Less than, for example, 0.1 g / cm 3 has a tap density of less than

[0052] The surface functionality of the porous carbon scaffolds can vary. One characteristic that can predict surface functionality is the pH of the porous carbon scaffolds. The porous carbon scaffolds of the present disclosure include pH values ​​ranging from less than 1 to about 14, such as less than 5, 5-8, or greater than 8. In some embodiments, the pH of the porous carbon is less than 4, less than 3, less than 2, or even less than 1. In other embodiments, the pH of the porous carbon is about 5-6, about 6-7, about 7-8, or 8-9, or 9-10. In still other embodiments, the pH is high and the pH of the porous carbon ranges from greater than 8, greater than 9, greater than 10, greater than 11, greater than 12, or even greater than 13.

[0053] The volume distribution of the porous carbon scaffold can vary. For example, the % micropores can be less than 30%, such as less than 20%, such as less than 10%, such as less than 5%, such as less than 4%, such as less than 3%, such as less than 2%, such as less than 1%, such as less than 0.5%, such as less than 0.2%, such as less than 0.1%. In certain embodiments, the porous carbon scaffold has no detectable micropore volume.

[0054] The mesopores that make up the porous carbon scaffold can vary. For example, the % mesopores can be less than 30%, such as less than 20%, such as less than 10%, such as less than 5%, such as less than 4%, such as less than 3%, such as less than 2%, such as less than 1%, such as less than 0.5%, such as less than 0.2%, such as less than 0.1%. In certain embodiments, the porous carbon scaffold has no detectable mesopore volume.

[0055] In some embodiments, the pore volume distribution of the porous carbon scaffold comprises more than 50% macropores, such as more than 60% macropores, such as more than 70% macropores, such as more than 80% macropores, such as more than 90% macropores, such as more than 95% macropores, such as more than 98% macropores, such as more than 99% macropores, such as more than 99.5% macropores, such as more than 99.9% macropores.

[0056] In certain preferred embodiments, the pore volume of the porous carbon scaffold comprises a blend of micropores, mesopores, and macropores. Thus, in certain embodiments, the porous carbon scaffold comprises 0-20% micropores, 30-70% mesopores, and less than 10% macropores. In other embodiments, the porous carbon scaffold comprises 0-20% micropores, 0-20% mesopores, and 70-95% macropores. In other specific embodiments, the porous carbon scaffold comprises 20-50% micropores, 50-80% mesopores, and 0-10% macropores. In other specific embodiments, the porous carbon scaffold comprises 40-60% micropores, 40-60% mesopores, and 0-10% macropores. In other specific embodiments, the porous carbon scaffold comprises 80-95% micropores, 0-10% mesopores, and 0-10% macropores. In other specific embodiments, the porous carbon scaffold comprises 0-10% micropores, 30-50% mesopores, and 50-70% macropores. In other specific embodiments, the porous carbon scaffold comprises 0-10% micropores, 70-80% mesopores, and 0-20% macropores. In other specific embodiments, the porous carbon scaffold comprises 0-20% micropores, 70-95% mesopores, and 0-10% macropores. In other specific embodiments, the porous carbon scaffold comprises 0-10% micropores, 70-95% mesopores, and 0-20% macropores.

[0057] In certain embodiments, the % of pore volume in the porous carbon scaffold exhibiting pores of 100-1000 A (10-100 nm) is more than 30% of the total pore volume, such as more than 40% of the total pore volume, such as more than 50% of the total pore volume, such as more than 60% of the total pore volume, such as more than 70% of the total pore volume, such as more than 80% of the total pore volume, such as more than 90% of the total pore volume, such as more than 95% of the total pore volume, such as more than 98% of the total pore volume, such as more than 99% of the total pore volume, such as more than 99.5% of the total pore volume, such as more than 99.9% of the total pore volume.

[0058] In certain embodiments, the pycnometric density of the porous carbon scaffold is in the range of about 1 g / cc to about 3 g / cc, for example, about 1.5 g / cc to about 2.3 g / cc. In other embodiments, the skeletal density is about 1.5 cc / g to about 1.6 cc / g, about 1.6 cc / g to about 1.7 cc / g, about 1.7 cc / g to about 1.8 cc / g, about 1.8 cc / g to about 1.9 cc / g, about 1.9 cc / g to about 2.0 cc / g, about 2.0 cc / g to about 2.1 cc / g, about 2.1 cc / g to about 2.2 cc / g, about 2.2 cc / g to about 2.3 cc / g, about 2.3 cc to about 2.4 cc / g, for example, about 2.4 cc / g to about 2.5 cc / g.

[0059] In some embodiments, the pore volume distribution of the carbon scaffold can be described as the number or volume distribution of pores, as measured as known in the art based on gas adsorption analysis, such as nitrogen gas adsorption analysis. In some embodiments, the pore size distribution can be expressed in terms of the pore size below which a certain fraction of the total pore volume is present. For example, the pore size below which 10% of the pores are present can be expressed as DPv10.

[0060] The DPv10 of the porous carbon scaffold may vary, for example, the DPv10 may be less than 100 nm, for example, 0.1 nm to 100 nm, for example, 1 nm to 100 nm, for example, 1 nm to 50 nm, for example, 1 nm to 40 nm, for example, 1 nm to 30 nm, for example, 1 nm to 10 nm, for example, 1 nm to 5 nm. In a particular embodiment, the DPv10 may be less than 100 nm, for example, less than 50 nm, for example, less than 10 nm, for example, less than 5 nm, for example, less than 4 nm, for example, less than 3 nm, for example, less than 2 nm, for example, less than 1 nm. The DPv10 of the porous carbon scaffold may vary, for example, the DPv10 may be less than 100 nm, for example, 0.1 nm to 100 nm, for example, 1 nm to 100 nm, for example, 1 nm to 50 nm, for example, 1 nm to 40 nm, for example, 1 nm to 30 nm, for example, 1 nm to 10 nm, for example, 1 nm to 5 nm. In certain embodiments, DPv10 may be less than 100 nm, such as less than 50 nm, such as less than 10 nm, for example less than 5 nm, such as less than 4 nm, for example less than 3 nm, such as less than 2 nm, for example less than 1 nm.

[0061] In certain embodiments, DPv20 may vary, such as less than 100 nm, such as less than 50 nm, for example less than 10 nm, such as less than 9 nm, for example less than 8 nm, such as less than 7 nm, for example less than 6 nm, such as less than 5 nm, for example less than 4 nm, such as less than 3 nm, for example less than 2 nm, such as less than 1 nm.

[0062] The DPv50 of the porous carbon scaffold may vary, for example, the DPv50 may be 0.01 nm to 100 nm, for example, 0.1 nm to 100 nm, for example, 1 nm to 100 nm, for example, 1 nm to 50 nm, for example, 1 nm to 40 nm, for example, 1 nm to 30 nm, for example, 1 nm to 10 nm, for example, 1 nm to 5 nm. In other embodiments, the DPv50 is 2 nm to 100 nm, for example, 2 nm to 50 nm, for example, 2 nm to 30 nm, for example, 2 nm to 20 nm, for example, 2 nm to 15 nm, for example, 2 nm to 10 nm, for example, 6 nm to 18 nm, for example, 8 nm to 16 nm, for example, 8 nm to 14 nm, for example, 8 nm to 12 nm.

[0063] The DPv80 of the porous carbon scaffold may vary, for example, the DPv80 may be from 0.01 nm to 100 nm, such as from 0.1 nm to 100 nm, for example from 1 nm to 100 nm, for example from 1 nm to 50 nm, for example from 1 nm to 40 nm, for example from 1 nm to 30 nm, for example from 1 nm to 10 nm, for example from 1 nm to 5 nm. In other embodiments, the DPv80 is from 5 nm to 30 nm, for example from 10 nm to 30 nm, for example from 10 nm to 20 nm, for example from 12 nm to 18 nm, for example from 12 nm to 16 nm, for example from 14 nm to 18 nm.

[0064] In some embodiments, the DPv80 is less than 100 nm, such as less than 50 nm, such as less than 40 nm, such as less than 30 nn, such as less than 20 nn, such as less than 15 nm, such as less than 10 nm, such as less than 5 nm, such as less than 4 nm, such as less than 3 nm. In some embodiments, the carbon scaffold comprises a pore volume having more than 70% micropores and a DPv80 of less than 100 nm, such as less than 50 nm, such as less than 40 nm, such as less than 30 nm, such as less than 20 nm, such as less than 15 nm, such as less than 10 nm, such as less than 5 nm, such as less than 4 nm, such as less than 3 nm. In other embodiments, the carbon scaffold has more than 80% micropores and comprises a pore volume having a DPv80 less than 100 nm, such as a DPv80 less than 50 nm, for example a DPv80 less than 40 nm, such as a DPv80 less than 30 nm, for example a DPv80 less than 20 nm, such as a DPv80 less than 15 nm, for example a DPv80 less than 10 nm, such as a DPv80 less than 5 nm, for example a DPv80 less than 4 nm, such as a DPv80 less than 3 nm.

[0065] The DPv90 of the porous carbon scaffold may vary, for example, the DPv90 may be 0.01 nm to 100 nm, for example, 0.1 nm to 100 nm, for example, 1 nm to 100 nm, for example, 1 nm to 50 nm, for example, 1 nm to 40 nm, for example, 1 nm to 30 nm, for example, 1 nm to 10 nm, for example, 1 nm to 5 nm. In other embodiments, the DPv50 is 2 nm to 100 nm, for example, 2 nm to 50 nm, for example, 2 nm to 30 nm, for example, 2 nm to 20 nm, for example, 2 nm to 15 nm, for example, 2 nm to 10 nm. In other embodiments, the DPv90 is 5 nm to 30 nm, for example, 10 nm to 30 nm, for example, 15 nm to 25 nm, for example, 16 nm to 24 nm, for example, 18 nm to 24 nm, for example, 8 nm to 10 nm.

[0066] In some embodiments, the DPv90 is less than 100 nm, such as less than 50 nm, for example less than 40 nm, such as less than 30 nn, for example less than 20 nn, such as less than 15 nm, for example less than 10 nm. In some embodiments, the carbon scaffold has more than 70% micropores and comprises a pore volume having a DPv90 of less than 100 nm, such as a DPv90 of less than 50 nm, for example a DPv90 of less than 40 nm, such as a DPv90 of less than 30 nm, for example a DPv90 of less than 20 nm, such as a DPv90 of less than 15 nm, for example a DPv90 of less than 10 nm, such as a DPv90 of less than 5 nm, for example a DPv90 of less than 4 nm, for example a DPv90 of less than 3 nm. In other embodiments, the carbon scaffold has more than 80% micropores and comprises a pore volume having a DPv90 of less than 100 nm, such as a DPv90 of less than 50 nm, for example a DPv90 of less than 40 nm, such as a DPv90 of less than 30 nm, for example a DPv90 of less than 20 nm, such as a DPv90 of less than 15 nm, for example a DPv90 of less than 10 nm, such as a DPv90 of less than 5 nm, for example a DPv90 of less than 4 nm, such as a DPv90 of less than 3 nm.

[0067] The DPv99 of the porous carbon scaffold may vary, for example, the DPv99 may be 0.01 nm to 1000 nm, for example, 0.1 nm to 1000 nm, for example, 1 nm to 500 nm, for example, 1 nm to 200 nm, for example, 1 nm to 150 nm, for example, 1 nm to 100 nm, for example, 1 nm to 50 nm, for example, 1 nm to 20 nm. In other embodiments, the DPv99 may be, for example, 2 nm to 500 nm, for example, 2 nm to 200 nm, for example, 2 nm to 150 nm, for example, 2 nm to 100 nm, for example, 2 nm to 50 nm, for example, 2 nm to 20 nm, for example, 2 nm to 15 nm, for example, 2 nm to 10 nm. In certain embodiments, the porous carbon scaffold has more than 70% micropores and comprises a pore volume with a DPv99 of less than 50 nm, such as less than 40 nm, for example less than 30 nm, such as less than 20 nm, for example less than 10 nm, such as less than 8 nm, for example less than 6 nm, such as less than 5 nm, for example less than 4 nm, for example less than 3 nm. In certain embodiments, the porous carbon scaffold has more than 80% micropores and comprises a pore volume with a DPv99 of less than 50 nm, for example less than 40 nm, for example less than 30 nm, such as less than 20 nm, for example less than 10 nm, such as less than 8 nm, for example less than 6 nm, for example less than 5 nm, for example less than 4 nm, for example less than 3 nm.

[0068] In certain embodiments, the carbon scaffold is modified prior to impregnation with lithium. For example, in certain embodiments, the surfaces of the carbon pores are functionalized with the goal of creating a more lithophilic surface, i.e., a surface that preferentially interacts with lithium or lithium-containing precursor materials, which may manifest as preferential diffusion, deposition, adsorption, etc.

[0069] C. Impregnation of lithium by chemical vapor infiltration (CVI) in porous carbon or silicon-carbon composites

[0070] Chemical vapor deposition (CVD) is a process in which a substrate provides a solid surface containing a first component of a composite, and a gas is pyrolyzed on the solid surface to provide a second component of the composite. Such CVD processes can be employed, for example, to make Li-C composite materials in which lithium is coated on the outer surface of carbon particles. Alternatively, chemical vapor infiltration (CVI) is a process in which a substrate provides a porous scaffold, also referred to as a porous framework, and a gas is pyrolyzed in the pores of the porous scaffold to provide a second component of the composite. In a preferred embodiment, the porous scaffold is a porous carbon scaffold and the gas is silane gas that pyrolyzes into silicon to provide a silicon-carbon composite material. The CVI reactor can be batch or continuous. The type of CVI reactor can be various, such as, for example, a static bed reactor, a moving bed reactor, a rotary kiln, a vibrating heat-assisted reactor as described in US2021 / 045417, a fluidized bed reactor, or other types of reactors known in the art. According to one embodiment of the present invention, a third component is also present in the pores of the porous carbon scaffold, either as a separate phase or alloyed in the silicon phase, where said third component is impregnated into the material by CVI. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to form a lithium-silicon-carbon composite material.

[0071] In a particular embodiment, the lithium and silicon are alloyed to obtain a lithium-silicon alloy phase by heating the silicon-carbon composite material in the presence of a lithium-containing precursor. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to produce a lithium-silicon alloy.

[0072] In some embodiments, a lithium-silicon-carbon composite material is made by heating a silicon-carbon composite material in the presence of a lithium-containing precursor, where the lithium comprises both lithium-silicon alloyed and non-alloyed domains. According to this embodiment, the lithium-silicon alloy-carbon composite is made by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to produce a lithium-silicon alloyed silicon-carbon composite, wherein the lithium also contains non-silicon alloy domains.

[0073] In some embodiments, lithium CVI is used to introduce lithium into the pores of the porous carbon using a porous carbon scaffold, and then silicon CVI is used to create silicon and / or lithium-silicon alloy or combinations thereof within the carbon pores. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material.

[0074] In a related embodiment, the lithium is present in the form of lithium alloyed with silicon within the pores of the carbon. a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a lithium-silicon alloy-carbon composite material.

[0075] In a related embodiment, the lithium is present in the form of an alloy of lithium and silicon within the carbon pores. a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework and provide a lithium-silicon alloy-carbon composite material, wherein the lithium also contains non-silicon-alloy domains.

[0076] In certain embodiments, the lithium-containing precursor is introduced in gaseous form. In other certain embodiments, the lithium-containing precursor is introduced in solid or liquid form and converted to gaseous form under conditions for carrying out the alloying process. The gasified lithium-containing precursor can be mixed with other inert gases, such as nitrogen, argon, and combinations thereof. The temperature and time of the process of incorporating lithium into the silicon-carbon composite may vary, for example the temperature may be between 100°C and 1700°C, such as between 100°C and 300°C, for example between 300°C and 400°C, for example between 400°C and 500°C, for example between 500°C and 600°C, for example between 600°C and 700°C, for example between 700°C and 800°C, for example between 800°C and 900°C, for example between 900°C and 1000°C, for example between 1000°C and 1100°C, for example between 1100°C and 1200°C, for example between 1200°C and 1400°C, for example between 1300°C and 1400°C, for example between 1400°C and 1700°C.

[0077] In one embodiment, lithium is gasified by heating to reach its boiling point (1330° C.) or higher. In other embodiments, lithium-containing precursors are gasified by heating to their boiling point or higher. Exemplary lithium-containing precursors in this regard include, but are not limited to, lithium bis(trimethylsilyl)amide (boiling point=84° C.), lithium acetylsalicylate (boiling point=350° C.), lithium amide (boiling point=430° C.), lithium bromide (boiling point=1265° C.), lithium borohydride (boiling point=380° C.), lithium chloride (boiling point=1383° C.), lithium hydride (boiling point=950° C.), and lithium hydroxide (boiling point=1626° C.).

[0078] The pressure of the lithium CVI process can vary. In some embodiments, the pressure is atmospheric. In some embodiments, the pressure is less than atmospheric. In some embodiments, the pressure is greater than atmospheric.

[0079] In some embodiments, the silicon CVI process is followed by a lithium CVI process. In other embodiments, silicon and lithium are introduced simultaneously by co-CVI processing. Without being bound by theory, the presence of hydrogen gas as a decomposition product from silane decomposition provides a reducing environment to promote lithium reduction and / or lithium alloying with silicon within the carbon pores. According to some embodiments, the conversion of the lithium-containing precursor to lithium can be achieved by a variety of methods, such as chemical or electrochemical reduction. In certain embodiments, the reduction is achieved by reaction in a reducing gas environment, such as hydrogen gas.

[0080] D. Impregnation of lithium in porous carbon or silicon-carbon composites by intrusion.

[0081] Melt infiltration is a process in which a liquid is infiltrated into the pores of a porous scaffold material. Such a melt infiltration approach can be employed, for example, to create lithium-silicon-carbon composite materials manufactured by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. Melting a lithium precursor in the presence of a silicon-carbon composite material to form a lithium-silicon-carbon composite material.

[0082] In a particular embodiment, a lithium precursor is melted in the presence of a silicon-carbon composite material to alloy the lithium and silicon to obtain a lithium-silicon alloy phase. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. Melting a lithium precursor in the presence of a silicon-carbon composite material to form a lithium-silicon-carbon composite material.

[0083] In some embodiments, a lithium-silicon-carbon composite material is produced by melting a lithium precursor in the presence of a silicon-carbon composite material, where the lithium includes both lithium-silicon alloyed and non-alloyed domains. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. Melting a lithium precursor in the presence of a silicon-carbon composite material to produce a lithium-silicon alloy-carbon composite, wherein the lithium also contains non-silicon-alloy domains.

[0084] In some embodiments, silicon and lithium are simultaneously introduced into the porous carbon framework by co-processing of silane CVI and melt infiltration of a lithium precursor to produce a lithium-silicon alloy-carbon composite as follows: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework in the presence of a silicon-containing gas and a lithium precursor at an elevated temperature to impregnate both silicon and lithium into one or more pores of the porous carbon framework, wherein the elevated temperature is above the melting point of the lithium precursor; and c. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon-alloy domains, or a combination thereof.

[0085] In some embodiments, lithium infiltration is accomplished prior to silicon CVI to create a lithium-silicon alloy-carbon composite as follows: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. melting a lithium precursor in the presence of a carbon framework to produce a lithium-silicon composite material; c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and d. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon-alloy domains, or a combination thereof.

[0086] The pressure of the melt infiltration process can vary. In some embodiments, the pressure is atmospheric. In some embodiments, the pressure is less than atmospheric. In some embodiments, the pressure is greater than atmospheric.

[0087] The temperature to achieve melt infiltration may vary, for example the temperature may be between 25°C and 1000°C, such as between 25°C and 100°C, for example between 100°C and 200°C, for example between 200°C and 300°C, for example between 300°C and 400°C, for example between 400°C and 500°C, for example between 500°C and 600°C, for example between 600°C and 700°C, for example between 700°C and 800°C, for example between 800°C and 900°C, for example between 900°C and 1000°C.

[0088] According to the melt infiltration process, the lithium may be in the form of elemental lithium, and the temperature of the process may vary, for example, above the melting point of lithium (180.5° C.). In other embodiments, the lithium is comprised in a lithium-containing precursor, which is heated above its melting point to facilitate the melt infiltration process. Exemplary lithium-containing precursors in this regard include lithium carbonate (melting point=723° C.), lithium acetate (melting point=286° C.), lithium amide (melting point=374° C.), lithium bromide (melting point=550° C.), lithium borohydride (melting point=268° C.), lithium peroxide (decomposes at about 340° C.), lithium chloride (melting point=610° C.), lithium fluoride (melting point=846° C.), lithium hydride (melting point=689° C.), lithium hydroxide (melting point=689° C.), lithium fluoride ... Lithium-containing precursors include, but are not limited to, lithium carbide (melting point=471° C.), lithium hydrogen sulfate (melting point=171° C.), lithium dihydrogen phosphate (melting point=100° C.), lithium nitrate (melting point=261° C.), lithium phosphate (melting point=837° C.), lithium nitride (melting point=813° C.), lithium sulfate (melting point=860° C.), lithium sulfide (melting point=950° C.), lithium disulfide (melting point=370° C.), and lithium sulfite (melting point=455° C.). Further exemplary lithium-containing precursors include lithium aluminum alloy (melting point=718° C.), lithium aluminum copper alloy (melting point of 600° C. to 655° C.), lithium tin alloy (melting point of 344° C. to 488° C.), and lithium silicon alloy (melting point=700° C.).

[0089] In some embodiments, the non-lithium components of the lithium precursor remain in the lithium-silicon-carbon composite material and can optionally function as electrochemical modifiers. In other embodiments, the non-lithium components of the lithium precursor are removed, for example, by decomposition, extraction, or other methods known in the art. In some embodiments, any lithium remaining in the carbon pores or outside the porous carbon scaffold can be removed by solvent washing. Exemplary solvents include, but are not limited to, tetrahydrofuran, toluene, or combinations thereof. In some embodiments, the lithium precursor introduced into the porous carbon by melt infiltration is converted to lithium by a chemical or electrochemical reduction process. Alternatively, the conversion of the lithium-containing precursor to lithium can be achieved by various methods, such as chemical or electrochemical reduction. In certain embodiments, the reduction is achieved by reaction with a reducing gas environment, such as hydrogen gas.

[0090] Exemplary agents for achieving the reduction of lithium-containing precursors to lithium include, but are not limited to, hydride reagents and dihydrogen, borohydrides such as lithium aluminum hydride, sodium borohydride or diborane, metal and organometallic reagents such as Grignard reagents, and dialkylcopper lithium (lithium dialkylcaprate) reagents such as sodium, alkylsodium and alkyllithium.

[0091] The melt infiltration process can be carried out in a batch process. Alternatively, the melt infiltration process can be carried out as a continuous process. In some embodiments, the melt infiltration process can be carried out as a continuous process employing extrusion.

[0092] Solution or suspension infiltration is a process in which a solution or suspension of lithium precursors infiltrates the pores of a porous carbon framework. Such suspension infiltration approach solutions can be employed to make lithium-silicon-carbon composite materials manufactured, for example, by processes including: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting a solution or suspension of a lithium precursor with the silicon-carbon composite to incorporate the lithium precursor into the silicon-carbon composite by solution or suspension infiltration; and d. Reducing the lithium precursor to produce a lithium-silicon-carbon composite material.

[0093] In certain embodiments, the solution or suspension immersion results in alloying of the lithium and silicon to provide a lithium-silicon alloy phase. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting a solution or suspension of a lithium precursor with the silicon-carbon composite to incorporate the lithium precursor into the silicon-carbon composite by solution or suspension infiltration; and d. Reduction of the lithium precursor to prepare a lithium-silicon alloy-carbon composite.

[0094] In some embodiments, solution or suspension immersion results in the production of a lithium-silicon-carbon composite material, where the lithium includes both lithium-silicon alloyed and non-alloyed domains. According to this embodiment, the lithium-silicon alloy-carbon composite is produced by a process that includes: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting a solution or suspension of a lithium precursor with the silicon-carbon composite to incorporate the lithium precursor into the silicon-carbon composite by solution or suspension infiltration; and d. Reducing a lithium precursor to produce a lithium-silicon alloy-carbon composite, wherein the lithium also contains non-silicon alloy domains.

[0095] In some embodiments, solution or suspension infiltration and reduction is accomplished prior to silicon CVI to create a lithium-silicon alloy-carbon composite as follows: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. reducing the lithium precursor to form a lithium-carbon composite; d. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and e. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof.

[0096] In other embodiments, solution or suspension infiltration is accomplished prior to silicon CVI and reduction occurs during silicon CVI to create a lithium-silicon alloy-carbon composite as follows: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. heating the lithium precursor-containing carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and d. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon-alloy domains, or a combination thereof.

[0097] The environment for solution or suspension immersion can be varied. For example, the environment can be aqueous. Alternatively, it can be an organic-based environment. One such example for solution immersion is lithium naphthalene, lithium biphenyl, lithium methylbiphenyl, or similar species of solutes in which the methyl and / or phenyl groups are present as di-, tri-, tetra-, or combinations thereof, in an aprotic ether solvent such as tetrahydrofuran, diethyl ether, dimethoxyethane, or combinations thereof.

[0098] Solution or suspension infiltration can be carried out in various process steps. In one embodiment, the porous carbon framework is introduced into a solution or suspension of the lithium precursor, and the particles of the porous carbon framework are kept in suspension, for example, by mixing, shaking, extrusion, or other suspension methods as known in the art. In some embodiments, the porous carbon framework containing the lithium precursor is removed from the solution or suspension, for example, by centrifugation, fluidized bed drying, vacuum drying, drying at atmospheric pressure, or other methods known in the art, or combinations thereof.

[0099] Exemplary lithium precursors for achieving solution or suspension infiltration into one or more pores of the porous carbon framework are varied. In this regard, exemplary lithium precursors include, but are not limited to, lithium carbonate, lithium acetate, lithium peroxide, lithium amide, lithium bromide, lithium borohydride, lithium chloride, lithium fluoride, lithium hydride, lithium hydroxide, lithium hydrogen sulfate, lithium dihydrogen phosphate, lithium nitrate, lithium phosphate, lithium nitride, lithium sulfate, lithium sulfide, lithium disulfide, lithium sulfite, and combinations thereof.

[0100] In some embodiments, the non-lithium components of the lithium precursor remain within the lithium-silicon-carbon composite and may optionally function as electrochemical modifiers. In other embodiments, the non-lithium components of the lithium precursor are removed, for example, by decomposition, extraction, or other methods known in the art. In some embodiments, any lithium remaining in the carbon pores or outside the porous carbon scaffold may be removed by solvent washing, exemplary solvents include, but are not limited to, naphthalene, toluene, or combinations thereof. In some embodiments, the lithium precursor introduced into the porous carbon by melt infiltration is converted to lithium by a chemical or electrochemical reduction process.

[0101] Exemplary reagents for achieving the reduction of lithium-containing precursors to lithium include, but are not limited to, hydride reagents and borohydrides such as dihydrogen, lithium aluminum hydride, sodium borohydride or diborane, metal and organometallic reagents such as Grignard reagents, and dialkyl copper lithium (lithium dialkyl caprate) reagents such as sodium, alkyl sodium and alkyl lithium. Alternatively, the conversion of lithium-containing precursors to lithium can be achieved by a variety of methods, such as chemical or electrochemical reduction. In certain embodiments, the reduction is achieved by reaction with a reducing gas environment, such as hydrogen gas.

[0102] The solution or suspension infiltration process may be carried out in a batch process. Alternatively, the solution or suspension infiltration process may be carried out as a continuous process. In some embodiments, the solution or suspension infiltration process may be carried out as a continuous process employing extrusion.

[0103] E. Lithium incorporation in silicon-carbon composites by co-processing with lithium and carbon precursors

[0104] In some embodiments, carbon and lithium precursors are co-processed to produce a lithium-silicon-carbon composite. Thus, a lithium precursor is incorporated into a carbon precursor, and the mixture is subjected to pyrolysis and activation to obtain a lithium precursor containing porous carbon scaffold, which is subjected to CVI in the presence of a silicon-containing gas to produce a lithium-silicon-carbon composite material.

[0105] According to some embodiments, the melting of the lithium-containing precursor is at or below the temperature employed to achieve thermal decomposition and / or activation to convert the carbon precursor to carbon. In one such embodiment, the lithium-containing precursor can be lithium metal. In other embodiments, the lithium-containing precursor can be a lithium-containing species disclosed elsewhere in this disclosure. In some embodiments, the melting and conversion of the lithium-containing precursor occurs at or below the temperature employed to achieve thermal decomposition and / or activation to convert the carbon precursor to carbon. Thus, the conversion of the lithium-containing precursor to lithium can be achieved by a variety of methods, such as chemical or electrochemical reduction. In certain embodiments, the reduction is achieved by reaction with a reducing gas environment, such as hydrogen gas.

[0106] Exemplary lithium-containing salts useful as precursors include, but are not limited to, dilithium tetrabromonickelate(II), dilithium tetrachlorocaprate(II), lithium azide, lithium nitrate, lithium nitride, lithium benzoate, lithium bromide, lithium carbonate, lithium chloride, lithium cyclohexanebutyrate, lithium fluoride, lithium formate, lithium hexafluoroarsenate(V), lithium hexafluorophosphate, lithium hydroxide, lithium iodate, lithium iodide, lithium metaborate, lithium perchlorate, lithium phosphate, lithium peroxide, lithium sulfate, lithium tetraborate, lithium tetrachloroaluminate, lithium tetrafluoroborate, lithium thiocyanate, lithium trifluoromethanesulfonate, lithium trifluoromethanesulfonate, lithium acetate, lithium formate, and combinations thereof.

[0107] F. Impregnation of silicon-carbon composites with lithium by electroplating

[0108] In one embodiment, the lithium-silicon-carbon composite material can be synthesized by an electroplating mechanism, where the electrolytic cell is charged with a lithium salt (e.g., LiPF 6, LiFSI, LiTFSI, LiCl, LiBr, LiI, LiNO 3 A separate porous carbon working electrode (prepared by slurry casting onto a copper foil or nickel sheet current collector) and a lithium metal counter electrode are combined in a liquid electrolyte containing anhydrous organic solvents (e.g., propylene carbonate, ethylene carbonate, 1,3-dioxolane, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, etc.) and anhydrous organic solvents (e.g., propylene carbonate, ethylene carbonate, 1,3-dioxolane, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, etc.). A negative voltage bias (e.g., -1V, -2V, -3V, -4V, -5V, -6V, etc.) is applied to promote the reduction of Li+ at the porous carbon electrode. The amount of charge transferred (Ah) is used to track the Li metal loading, and then the applied voltage is stopped once the desired Li loading is achieved. The electrode containing the lithium-silicon-carbon composite can then be transferred and used as the anode in a lithium-ion battery.

[0109] Thus, a porous electrode comprising a silicon-carbon composite is prepared on a roll-to-roll coater and then transferred into an electrolyte bath (described above) housed in an inert atmosphere, where a negative voltage bias is applied as in the above-described embodiment, and lithium plating occurs while the electrode is continuously moving on the roller. The degree of lithium metal loading is therefore determined by the transport speed of the roll-to-roll machine. Additionally, the electrolyte bath may contain dissolved polymers (e.g., polyacrylonitrile, polyvinylidene fluoride, polydopamine, etc.) such that when the electrode is removed from the bath and subsequently dried, a polymer film is left on the electrode surface acting as a barrier to the atmosphere, thus minimizing oxidation of the lithium metal formed on the porous carbon.

[0110] In another more preferred embodiment, lithium alloying can be performed in-situ in an as-assembled lithium ion battery, where a porous electrode comprising a silicon-carbon composite is the anode and is filled with a conventional lithium-containing transition metal oxide as known in the art (e.g., LiFePO 4 , LiCoO 2, NCA, NMC111, NMC532, NMC622, etc.) serves as the cathode. Electroplating of lithium occurs when the battery is charged to 100% state-of-charge operating voltage (e.g., 4.2V). In this "anode-free" configuration, the Li+ source is the cathode. When the battery is discharged, the process is reversed (Li+ stripping from the porous carbon electrode). This embodiment is preferred as it eliminates the need to handle reactive lithium metal in the environment outside the battery, and further improves the energy density of the battery since the cathode serves as the only source of Li+ in the system.

[0111] In embodiments where the lithium-plated scaffold is a porous and conductive but non-carbon material (e.g., copper, nickel, silicon, titanium, aluminum foil, Styrofoam, etc.), the substrate can be acid etched (e.g., HCl, HNO 3 , and / or HF, etc.) or laser patterning to enhance lithium loading capabilities. Non-carbon scaffold materials can undergo alloying reactions with lithium prior to subsequent plating, thereby reducing dendrite formation. The high intrinsic electrical conductivity of these scaffolds can also lead to improved rate capabilities of the battery.

[0112] The kinetics of lithium alloying in the above embodiments may be controlled either galvanostatically (constant current) or potentiostatically (constant voltage). Galvanostatic plating is most advisable in the "anode-free" configuration of the as-assembled lithium-ion battery. Current densities may range from 0.1-0.5, 0.5-1, 1-2, 2-3, 3-4, or 4-5 mA / cm. 2 It may be more preferable to control the voltage in lithium plating, especially when the resistance is high and / or the electrode distance is large. Some examples of the voltage between the two electrodes may include -0.1 to -0.5, -0.5 to -1, -1 to -2, -2 to -3, -3 to -4, and -4 to -6 V. The electrolyte used in these electroplating systems is one or more lithium salts (e.g., LiPF6 , LiFSI, LiTFSI, LiCl, LiBr, LiI, LiNO 3 , LiBOB, LiClO 4 etc.), and the concentration may be 0.1-0.5, 0.5-1, 1-2, 2-3, and 3-4 molar. In a solvent consisting of one or more anhydrous organic solvents (e.g., propylene carbonate, ethylene carbonate, diethyl carbonate, fluoroethylene carbonate, vinylidene carbonate, 1,3-dioxolane, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, etc.) or ionic liquids (e.g., 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide, N-ethyl-N-methylpyrrolidinium fluorohydrogenate, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide).

[0113] G. Surface-modified lithium-silicon-carbon composites

[0114] In certain embodiments, the lithium-silicon-carbon composite particles include a modified surface, such as a coating or molecular bonding to the surface phase. Without being bound by theory, this modification can provide advantages such as improved electrochemical performance, material handling, improved battery structure and safety of battery operation. The modification can be a coating, which can at least partially cover the surface of the lithium-silicon-carbon composite material.

[0115] In a preferred embodiment, the coating on the lithium-silicon alloy-carbon composite prevents any reaction with oxygen molecules, thus providing stable storage and handling in air for the coated lithium-silicon-carbon composite material. According to some embodiments, the carbonaceous layer is formed by CVD as known in the art. According to other embodiments, the carbonaceous layer is formed by chemical vapor passivation (CVP), as disclosed in US2021 / 052995.

[0116] In certain embodiments, the surface layer may include a carbon layer. It is envisioned that the surface layer provides a suitable SEI layer. In the present disclosure, the surface carbon layer needs to be a good ion conductor for shuttle Li ions. Alternatively, the carbon layer may include an artificial SEI layer, for example, the carbon layer may include poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) copolymer. The coating may include nitrogen and / or oxygen functional groups to further improve the layer with respect to promoting a stable SEI layer. The coating needs to provide sufficient electrical conductivity, adhesion, and cohesion between particles. The surface needs to provide a stable SEI layer, the latter of which is typically LiF, Li 2 CO 3 , Li 2 O. Inorganic materials with relatively low bulk modulus may provide a more stable SEI layer, e.g., Li 2 CO 3 A more amorphous vs crystalline layer, such as LiF vs LiF, is preferred.

[0117] For the purposes of this disclosure, a carbon layer may be applied to the lithium-silicon-carbon composite particles. Without being bound by theory, this carbon layer should provide a low surface area to provide a more stable SEI layer, higher first cycle efficiency, and greater cycle stability in lithium ion batteries. In the context of providing a surface layer to silicon-impregnated porous carbon materials, various carbon allotropes may be envisioned, including graphite, graphene, hard carbon, or soft carbon (e.g., pyrolytic carbon).

[0118] In an alternative embodiment, the coating can be achieved using a precursor solution as known in the art, followed by a carbonization process. For example, the particles can be coated by the Wurster process, or a related spray drying process, as known in the art, to apply a thin layer of precursor material onto the particles. The precursor coating can then be pyrolyzed by further fluidizing the Wurster-coated particles at elevated temperatures and in the presence of an inert gas, for example, as described elsewhere herein.

[0119] In an alternative embodiment, the particles may be covered with a carbonaceous layer achieved by chemical vapor deposition (CVD). Without wishing to be bound by theory, it is believed that the CVD method of depositing a carbon layer (e.g., from a hydrocarbon gas) results in graphitizable carbon (also referred to in the art as "soft" carbon). The composite materials disclosed herein are amenable to CVD methodologies generally described in the art. CVD is generally achieved by treating a composite particulate material at high temperature for a period of time in the presence of a suitable deposition gas containing carbon atoms. Suitable gases in the present disclosure include, but are not limited to, methane, propane, butane, cyclohexane, ethane, propylene, ethylene, and acetylene. The temperature may vary, for example, from 350 to 1050°C, for example, from 350 to 450°C, for example, from 450 to 550°C, for example, from 550 to 650°C, for example, from 650 to 750°C, for example, from 750 to 850°C, for example, from 850 to 950°C, for example, from 950 to 1050°C. In a particular embodiment, the deposition gas is methane and the deposition temperature is 950°C or higher. In a particular embodiment, the deposition gas is propane and the deposition temperature is 750°C or lower. In a particular embodiment, the deposition gas is cyclohexane and the deposition temperature is 800°C or higher. In a particular embodiment, the deposition gas is acetylene and the deposition temperature is 400°C or higher. In a particular embodiment, the deposition gas is ethylene and the deposition temperature is 500°C or higher. In a particular embodiment, the deposition gas is propylene and the deposition temperature is 400°C or higher.

[0120] In certain embodiments, the reactor to achieve coating may be stirred to agitate the lithium-silicon-carbon composite particles. In other exemplary aspects, the particles may be fluidized, e.g., impregnation with the silicon-containing reactant may be carried out in a fluidized bed reactor. As is known in the art, a variety of reactor designs may be employed in the present disclosure, including, but not limited to, elevator kilns, roller hearth kilns, rotary kilns, box kilns, and modified fluidized bed designs.

[0121] The thickness of the carbon coating may vary, for example, from 1-2 nm, 2-5 nm, 5-10 nm, 10-20 nm, 20-50 nm, or 50-100 nm. The mass percentage of the carbon coating on the lithium carbon composite particles as a fraction of the mass of the total particle may vary, for example, from 0.01-0.1%, 0.1-0.5%, 0.5-1%, 1-2%, 2-5%, or greater than 5%. In alternative embodiments, the terminal carbon coating may be 0.1% to 5%.

[0122] The composite material including lithium, silicon, and carbon may also include a carbon-free terminal coating. In some embodiments, such a non-carbonaceous coating may be achieved by atomic layer deposition (ALD), as known in the art. The thickness of the ALD coating may vary, for example, from 1-2 nm, 2-5 nm, 5-10 nm, 10-20 nm, 20-50 nm, or 50-100 nm. The mass percentage of the ceramic coating on the lithium carbon composite particles as a fraction of the mass of the total particle may vary, for example, from 0.01-0.1%, 0.1-0.5%, 0.5-1%, 1-2%, 2-5%, or greater than 5%. Exemplary non-carbonaceous coatings in this regard include, but are not limited to, aluminum-containing oxides, zirconium-containing oxides, titanium-containing oxides, and niobium-containing oxides. In alternative embodiments, the terminal ALD coating may be 0.1%-5% (wt / wt).

[0123] The lithium-silicon-carbon composite material may be provided with a terminal carbon coating by hydrothermal carbonization, where the particles are treated in various manners according to the art. The hydrothermal carbonization may be carried out in an aqueous environment at high temperature and pressure. Examples of temperatures to achieve hydrothermal carbonization vary, such as 150°C to 300°C, such as 170°C to 270°C, such as 180°C to 260°C, such as 200°C to 250°C. Alternatively, the hydrothermal carbonization may be carried out at higher temperatures, such as 200°C to 800°C, such as 300°C to 700°C, such as 400°C to 600°C. In some embodiments, the hydrothermal carbonization may be carried out at a temperature and pressure to achieve a graphitic structure. The range of pressures suitable for carrying out hydrothermal carbonization is known in the art, and the pressure may be changed, e.g., increased, during the course of the reaction. The pressure of the hydrothermal carbonization may vary from 0.1 MPa to 200 MPa. In certain embodiments, the pressure of the hydrothermal carbonization is 0.5 MPa to 5 MPa. In other embodiments, the pressure of the hydrothermal carbonization is 1 MPa to 10 MPa, or 5 MPa to 20 MPa. In yet other embodiments, the pressure of the hydrothermal carbonization is 10 MPa to 50 MPa. In yet other embodiments, the pressure of the hydrothermal carbonization is 50 MPa to 150 MPa. In yet other embodiments, the pressure of the hydrothermal carbonization is 100 MPa to 200 MPa. Feedstocks suitable as carbon sources for hydrothermal carbonization are also known in the art. Such feedstocks for hydrothermal carbonization typically contain carbon and oxygen, and include, but are not limited to, sugars, oils, biowastes, polymers, and polymer precursors as described anywhere in the present disclosure.

[0124] H. Doping with Electrochemical Modifiers

[0125] In certain embodiments, the lithium-silicon-carbon composite materials can be doped with species that achieve modifications of the electrochemical properties. Such electrochemical modifiers can provide enhanced electrochemical properties, including, but not limited to, increased capacity, reduced resistance, increased storage stability, suppression of lithium metal dendrites, and increased cycling stability.

[0126] In some embodiments, the electrochemical modifier serves to inhibit the formation of lithium dendrites. The growth of lithium dendrites as a result of continuous (often high rates) lithium plating / stripping can lead to shorting of the electrodes, resulting in battery failure (sometimes catastrophic). Porous carbon particles and / or their electrodes decorated with nanometal seeds (e.g., Sn, Ni, In, Ag, Zn, Al, etc.) can alloy and / or form eutectic with lithium before the plating voltage is reached. This can act to inhibit dendrite formation by mitigating highly localized current regions and lowering the overpotential (and therefore resistance) of lithium plating. In certain related embodiments, the electrochemical modifier is a metal oxide, such as an oxide of Sn, Ni, In, Ag, Zn, Al, etc., or a combination thereof. In certain related embodiments, the electrochemical modifier comprises a phosphate, such as a transition metal phosphate, an alkali metal phosphate, or a rare earth metal phosphate.

[0127] In certain embodiments, the electrochemical modifier can be present as a non-metal dopant, for example, oxygen, nitrogen, fluorine, chlorine, phosphorus, silicon, transition metals, etc. Without being bound by theory, the non-metal dopant functions as an electronegative site to attract and grow lithium.

[0128] I. Physical and electrochemical properties of lithium-silicon-carbon composites.

[0129] In certain embodiments, the lithium particles embedded in the composite have nano-sized features. The nano-sized features may have a characteristic length scale of, for example, less than 2 nm, between 2 nm and 50 nm, or greater than 50 nm. In certain embodiments, the lithium-silicon alloy phase is embedded in the composite and has nano-sized features. The nano-sized features may have a characteristic length scale of, for example, less than 2 nm, between 2 nm and 50 nm, or greater than 50 nm.

[0130] The distribution of lithium and / or lithium-silicon alloy within the lithium-silicon-carbon composite may vary, for example, lithium and / or lithium-silicon alloy may be impregnated into the pores of the porous carbon, where the fractional filling of the carbon internal void volume may vary. For example, the percentage of lithium and / or lithium-silicon alloy filling within the total carbon pore volume may be 1-90%, for example, 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, or 80%-90%. Alternatively, the percentage of lithium and / or lithium-silicon alloy filling within the total carbon pore volume may be 15-85%, for example, 20%-80%, 30%-70%, or 40%-60%.

[0131] The lithium domains may exist as non-alloyed phases, e.g., interspersed within the carbon skeletal structure, and / or the lithium domains may be completely surrounded by carbon. The geometry of the lithium domains within the carbon may vary, e.g., spherical, cylindrical, or serpentine. In some embodiments, the lithium exists as a layer coating the inside of the pores within the porous carbon scaffold.

[0132] The size of the impregnated lithium and / or lithium-silicon alloy may vary, for example, less than 2 nm, 2 nm to 5 nm, 5 nm to 10 nm, 5 nm to 20 nm, 5 nm to 30 nm, 2 nm to 50 nm, 2 nm to 30 nm, 5 nm to 50 nm, 10 nm to 100 nm, 10 nm to 150 nm, 50 nm to 150 nm, 300 nm to 1000 nm, or 2 nm to 1000 nm.

[0133] The specific physicochemical and electrochemical properties of the lithium-silicon-carbon composites can vary, and are illustrated in Table 1.

[0134] Table 1. Lithium carbon composite properties [Table 1]

[0135] According to Table 1, the lithium-silicon carbon composites can include a variety of combinations of properties. For example, the lithium-silicon-carbon composites can have a 100m 2 / g, a first cycle efficiency of greater than 80%, and a reversible capacity of at least 1300 mAh / g; or 2 / g, a first cycle efficiency of greater than 80%, and a reversible capacity of at least 1600 mAh / g; or 2 / g, a first cycle efficiency of greater than 85%, and a reversible capacity of at least 1600 mAh / g; or 2 / g, a first cycle efficiency of greater than 85%, and a reversible capacity of at least 1600 mAh / g, or 2 / g, a first cycle efficiency of greater than 90%, and a reversible capacity of at least 1600 mAh / g; or 2 / g, a first cycle efficiency of greater than 90%, and a reversible capacity of at least 1800 mAh / g.

[0136] The lithium carbon composite may include a combination of the aforementioned properties in addition to including a carbon scaffold that includes the properties also described in this disclosure. Thus, Table 2 provides a description of certain embodiments of the combination of properties for lithium-silicon carbon composites.

[0137] Table 2. Lithium-silicon-carbon composite properties [Table 2]

[0138] As used herein, the percentages of "microporosity," "mesoporosity," and "macroporosity" refer to the percentage of micropores, mesopores, and macropores, respectively, as a percentage of the total pore volume. For example, a carbon scaffold having 90% microporosity is a carbon scaffold in which 90% of the total pore volume of the carbon scaffold is formed by micropores.

[0139] According to Table 2, the lithium-silicon-carbon composites can include a variety of combinations of properties. For example, the lithium-silicon-carbon composites can have a 100m 2 / g surface area, greater than 85% first cycle efficiency, at least 1600 mAh / g reversible capacity, 0.1% to 20% lithium content, 30% to 70% silicon content, 0.2 to 1.2 cm 3 / g, where the pore volume of the scaffold includes more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, a lithium-silicon-carbon composite material can have a total pore volume of 20 m 2 / g surface area, greater than 85% first cycle efficiency, at least 1600 mAh / g reversible capacity, 0.1% to 20% lithium content, 30% to 70% silicon content, 0.2 to 1.2 cm 3 / g, where the pore volume of the scaffold includes more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, a lithium-silicon-carbon composite material can have a total pore volume of 10 m 2 / g surface area, greater than 85% first cycle efficiency, at least 1600 mAh / g reversible capacity, 0.1% to 20% lithium content, 30% to 70% silicon content, 0.2 to 1.2 cm 3 / g, where the pore volume of the scaffold includes more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, a lithium-silicon-carbon composite can have a total pore volume of 10 m 2 / g surface area, greater than 90% first cycle efficiency, at least 1600 mAh / g reversible capacity, 0.1% to 20% lithium content, 30% to 70% silicon content, 0.2 to 1.2 cm 3 / g, where the pore volume of the scaffold includes more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, a lithium-silicon-carbon composite can have a total pore volume of 10 m 2 / g surface area, greater than 90% first cycle efficiency, and at least 1800 mAh / g reversible capacity, 0.1% to 20% lithium content, 30% to 70% silicon content, 0.2 to 1.2 cm 3 / g of the total pore volume of the carbon scaffold, the pore volume of the scaffold comprising greater than 80% micropores, less than 20% mesopores, and less than 10% macropores.

[0140] The lithium-silicon-carbon composite material may also have inaccessible intraparticle void volumes, e.g., volumes that are inaccessible to nitrogen gas. Thus, the lithium carbon composite material may have a void volume of 2.1 g / cm 3 Less than, for example, 2.0 g / cm 3 Less than, for example, 1.9 g / cm 3 Less than, for example, 1.8 g / cm 3 Less than, for example, 1.7 g / cm 3 Less than 9g / cm3 Less than, for example, 1.8 g / cm 3 Less than, for example, 1.7 g / cm 3 Less than, for example, 1.6 g / cm 3 Less than, for example, 1.4 g / cm 3 Less than, for example, 1.2 g / cm 3 Less than 1.0g / cm 3 It may exhibit a pycnometric density of less than 0.1.

[0141] In some embodiments, the lithium-silicon-carbon composite material has a density of 1.7 g / cm 3 ~2.1g / cm 3 , e.g. 1.7g / cm 3 ~1.8g / cm 3 , 1.8g / cm 3 ~1.9g / cm 3 , e.g. 1.9g / cm 3 ~2.0g / cm 3 , e.g. 2.0g / cm 3 ~2.1g / cm 3 In some embodiments, the lithium-silicon-carbon composite material may exhibit a pycnometric density of 1.8 g / cm. 3 ~2.1g / cm 3 In some embodiments, the lithium-silicon-carbon composite material may exhibit a pycnometric density of 1.8 g / cm. 3 ~2.0g / cm 3 In some embodiments, the lithium carbon composite material may exhibit a pycnometric density of 1.9 g / cm 3 ~2.1g / cm 3 It may exhibit a pycnometric density of

[0142] The lithium-silicon-carbon composite material exhibits extremely durable lithium intercalation with a pore volume of 0.01 cm 3 / g~0.2cm 3 In certain embodiments, the pore volume of the lithium-silicon carbon composite material may be less than 0.01 cm3 / g. 3 / g~0.15cm 3 / g, e.g. 0.01 cm3 / g~0.1cm 3 / g, e.g. 0.01 cm 3 / g~0.05cm 3 / g.

[0143] The particle size distribution of the lithium-silicon-carbon composite is important in determining both power performance and volumetric capacity. Improved packing can increase volumetric capacity. In some embodiments, the particle size distribution is Gaussian with a single peak. In other embodiments, the particle size distribution includes multiple modes, e.g., bimodal, or multimodal (two or more distinct peaks, e.g., trimodal). The particle size distribution can have a right skew. In other embodiments, the particle size distribution can have a left skew. The composite particle size characteristics can be described by a volumetric particle size distribution, e.g., Dv1, Dv10, Dv50, Dv90, Dv99, etc., as known in the art. The optimal combination of particle packing and performance will be some combination of the following size ranges. Particle size reduction in such embodiments can be performed by jet milling in the presence of various gases, e.g., air, nitrogen, argon, helium, supercritical water vapor, and other gases known in the art, as known in the art.

[0144] In one embodiment, the Dv1 of the composite material may be in the range of 1 nm to 5 microns. In another embodiment, the Dv1 of the composite is in the range of 5 nm to 1 micron, such as 5 to 500 nm, such as 5 to 100 nm, such as 10 to 50 nm. In another embodiment, the Dv1 of the composite is in the range of 500 nm to 2 microns, or 750 nm to 1 μm, or 1 to 2 μm. In other embodiments, the Dv1 of the composite is in the range of 2 to 5 μm, or greater than 5 μm. In a preferred embodiment, Dv1<5 μm, or Dv1<3 μm, Dv1<2 μm, Dv1<1.

[0145] The Dv10 of the composite material may be in the range of 1 nm to 10 μm. In a preferred embodiment, Dv10<10 μm, or Dv10<8 μm, Dv10<6 μm, Dv10<5 μm, Dv10<4 μm, Dv10<3 μm, Dv10<2 μm.

[0146] In some embodiments, the Dv50 of the composite material is between 5 nm and 20 μm. In other embodiments, the Dv50 of the composite is between 5 nm and 1 μm, such as between 5 and 500 nm, such as between 5 and 100 nm, such as between 10 and 50 nm. In other embodiments, the Dv50 of the composite is between 500 nm and 2 μm, such as between 750 nm and 1 μm, such as between 1 and 2 μm. In yet other embodiments, the Dv50 of the composite is between 1 and 1000 μm, such as between 1 and 100 μm, such as between 1 and 10 μm, such as between 2 and 20 μm, such as between 3 and 15 μm, such as between 4 and 8 μm. In certain embodiments, the Dv50 is >20 μm, such as >50 μm, such as >100 μm.

[0147] The Dv90 of the composite material may be in the range of 1 μm to 50 μm. In preferred embodiments, the Dv90 is in the range of 1 μm to 30 μm, 2 μm to 25 μm, 3 μm to 20 μm, 4 μm to 20 μm, 5 μm to 20 μm, 6 μm to 20 μm, 8 μm to 20 μm, 10 μm to 20 μm, or 15 μm to 20 μm. In other embodiments, the Dv90 is less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or less than 15 μm.

[0148] The Dv99 of the composite material may range from 1 μm to 50 μm. In preferred embodiments, Dv90 ranges from 1 μm to 30 μm, 2 μm to 25 μm, 3 μm to 25 μm, 4 μm to 25 μm, 5 μm to 25 μm, 6 μm to 20 μm, 8 μm to 20 μm, 10 μm to 20 μm, or 15 μm to 25 μm. In other embodiments, Dv90 is less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or less than 15 μm.

[0149] The span (Dv90-Dv10) / (Dv50) can vary, for example, from 100 to 10, from 10 to 5, from 5 to 2, from 2 to 1. Here, Dv10, Dv50, and Dv90 represent the particle sizes at 10%, 50%, and 90% of the volume distribution; in some embodiments, the span can be less than 1. In certain embodiments, the composite material comprises a particle size distribution that is unimodal. In certain embodiments, the particle size distribution of the composite material has a right skew. In certain embodiments, the particle size distribution of the composite material has a left skew. In certain embodiments, the particle size distribution of the composite material can be multimodal, for example, bimodal or trimodal.

[0150] The surface functionality of the composite materials of the present disclosure, which exhibit extremely durable intercalation of lithium, may be tailored to obtain desired electrochemical properties. One property that can predict surface functionality is the pH of the composite material. The composite materials of the present disclosure include pH values ​​ranging from less than 1 to about 14, such as less than 5, 5 to 8, or greater than 8. In some embodiments, the pH of the composite material is less than 4, less than 3, less than 2, or even less than 1. In other embodiments, the pH of the composite material is about 5 to 6, about 6 to 7, about 7 to 8, 8 to 9, or 9 to 10. In still other embodiments, the pH is high and the pH of the composite material ranges from greater than 8, greater than 9, greater than 10, greater than 11, greater than 12, or even greater than 13.

[0151] The composite material may contain varying amounts of carbon, oxygen, hydrogen, and nitrogen as measured by gas chromatography CHNO analysis. In one embodiment, the carbon content of the composite is greater than 98 wt%, or even greater than 99.9 wt%, as measured by CHNO analysis. In another embodiment, the carbon content of the lithium-carbon composite is in the range of about 10-90%, such as 20-80%, such as 30-70%, such as 40-60%.

[0152] In some embodiments, the composite material has a nitrogen content in the range of 0-90%, such as 0.1-1%, for example 1-3%, such as 1-5%, for example 1-10%, such as 10-20%, for example 20-30%, for example 30-90%.

[0153] In some embodiments, the composite material has an oxygen content in the range of 0-90%, such as 0.1-1%, for example 1-3%, such as 1-5%, for example 1-10%, such as 10-20%, for example 20-30%, for example 30-90%.

[0154] The morphology of the carbon scaffold particles can vary, for example, the carbon scaffold particles are spherical in shape.

[0155] The composite material may incorporate electrochemical modifiers selected to optimize the electrochemical performance of the unmodified composite. The electrochemical modifiers may be incorporated within the pore structure and / or on the surface of the porous carbon scaffold, embedded lithium, or within the final layer of a carbon, or conductive polymer, coating, or may be incorporated in any number of other ways. For example, in some embodiments, the composite material incorporates an electrochemical modifier (e.g., lithium or Al) on the surface of the carbon material. 2 O 3 In some embodiments, the composite material comprises greater than about 100 ppm of an electrochemical modifier. In certain embodiments, the electrochemical modifier is selected from iron, tin, nickel, aluminum, and manganese.

[0156] In certain embodiments, the electrochemical modifier comprises an element capable of lithiation between 3 V and 0 V versus lithium metal (e.g., silicon, tin, sulfur). In other embodiments, the electrochemical modifier comprises a metal oxide capable of lithiation between 3 V and 0 V versus lithium metal (e.g., iron oxide, molybdenum oxide, titanium oxide). In yet other embodiments, the electrochemical modifier comprises an element that does not lithiate between 3 V and 0 V versus lithium metal (e.g., aluminum, manganese, nickel, metal phosphates). In yet other embodiments, the electrochemical modifier comprises a non-metal element (e.g., fluorine, nitrogen, hydrogen). In still other embodiments, the electrochemical modifier comprises any of the aforementioned electrochemical modifiers, or a combination thereof (e.g., tin-silicon, nickel-titanium oxide).

[0157] The electrochemical modifier may be provided in a number of forms. For example, in some embodiments, the electrochemical modifier comprises a salt. In other embodiments, the electrochemical modifier comprises one or more elements in elemental form, such as elemental iron, tin, silicon, nickel, or manganese. In other embodiments, the electrochemical modifier comprises one or more elements in oxidized form, such as iron oxide, tin oxide, silicon oxide, nickel oxide, aluminum oxide, or manganese oxide.

[0158] The electrochemical properties of the composite material may be modified, at least in part, by the amount of electrochemical modifier in the material, where the electrochemical modifier is an alloy material such as silicon, tin, indium, aluminum, germanium, gallium, etc. Thus, in some embodiments, the composite material comprises at least 0.10%, at least 0.25%, at least 0.50%, at least 1.0%, at least 5.0%, at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, at least 95%, at least 99%, or at least 99.5% electrochemical modifier.

[0159] It is envisioned that the composite material in certain embodiments contains a portion of trapped pore volume, i.e., void volume that is inaccessible to nitrogen gas, as probed by nitrogen gas adsorption measurements. Without wishing to be bound by theory, this trapped pore volume is important in that it provides a volume into which silicon can expand upon lithiation. The internal void volume can be measured by a variety of methods, such as pycnometry density and / or press density.

[0160] In certain embodiments, the percentage of non-accessible void volume relative to the total volume of the composite particle is in the range of 0.1% to 90%, such as in the range of 5% to 85%, 10% to 70%, 20% to 60%, 20% to 50%, 20% to 40%, or 30% to 40%.

[0161] In certain embodiments, the electrochemical performance of the composites disclosed herein is tested in half cells; alternatively, the performance of the composites is tested in full cells, such as full cell coin cells, full cell pouch cells, prism cells, or other battery configurations known in the art. The anode composition including the composites may further include various species as known in the art. Additional formulation ingredients include, but are not limited to, conductive carbons such as Super C45, Super P, Ketjen Black carbon, conductive additives such as conductive polymers, binders such as styrene-butadiene rubber sodium carboxymethylcellulose (SBR-Na-CMC), polyvinylidene fluoride (PVDF), polyimide (PI), polyacrylic acid (PAA), and combinations thereof. In certain embodiments, the binder may include lithium ions as counter ions (e.g., lithium polyacrylate (LiPAA), lithium carboxymethylcellulose (LiCMC), etc.).

[0162] Other species constituting the electrode are known in the art. The weight percent of active material in the electrode can vary, for example, 1-5%, for example, 5-15%, for example, 15-25%, for example, 25-35%, for example, 35-45%, for example, 45-55%, for example, 55-65%, for example, 65-75%, for example, 75-85%, for example, 85-95%, etc. In some embodiments, the active material constitutes 80-95% of the electrode. In certain embodiments, the amount of conductive additive in the electrode can vary, for example, 1-5%, 5-15%, for example, 15-25%, for example, 25-35%. In some embodiments, the amount of conductive additive in the electrode is 5-25%. In certain embodiments, the amount of binder can vary, for example, 1-5%, 5-15%, for example, 15-25%, for example, 25-35%. In certain embodiments, the amount of conductive additive in the electrode is 5-25%.

[0163] Anodes comprising the lithium-silicon-carbon composites can be combined with various cathode materials to form full-cell lithium silicon batteries. Examples of suitable cathode materials are known in the art. Examples of such cathode materials include LiCoO 2 (LCO), LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (NMC), LiNi 0.5 Mn 1.5 O 4 (LNMO), LiMn 2 O 4 and derivatives (LMO), LiFePO 4 (LFP), FeF 2 , CuF 2 and S.

[0164] In batteries containing lithium-silicon-carbon composites, the pairing ratio of cathode to anode can vary. The pairing ratio is on a capacity cathode to capacity anode basis, e.g., Ah cathode to Ah anode basis, or Ah / cm 2 Ah / cm relative to anode reference 2 It is a unit of the cathode. For example, the capacity ratio of the cathode to the anode may vary from 0.7 to 1.3. In certain embodiments, the capacity ratio of the cathode to the anode may vary from 0.7 to 1.0, such as from 0.8 to 1.0, such as from 0.85 to 1.0, such as from 0.9 to 1.0, such as from 0.95 to 1.0. In other embodiments, the capacity ratio of the cathode to the anode may vary from 1.0 to 1.3, such as from 1.0 to 1.2, such as from 1.0 to 1.15, such as from 1.0 to 1.1, such as from 1.0 to 1.05. In still other embodiments, the capacity ratio of the cathode to the anode may vary from 0.8 to 1.2, such as from 0.9 to 1.1, such as from 0.95 to 1.05.

[0165] In a preferred embodiment, for a battery comprising the lithium-silicon-carbon composite, the cathode to anode pairing is less than 1.00 and the first cycle efficiency is, for example, greater than 80%, such as greater than 85%, for example greater than 90%, such as greater than 91%, for example greater than 92%, such as greater than 93%, for example greater than 94%, such as greater than 95%, for example greater than 96%, such as greater than 97%, for example greater than 98%, such as greater than 99%.

[0166] In a full cell lithium silicon battery including a lithium-silicon-carbon composite, the voltage window of charging and discharging can vary. In this regard, the voltage window can vary as known in the art. For example, the choice of cathode plays a role in the selected voltage window, as known in the art. Examples of voltage windows, for example, in terms of potential vs Li / Li+, vary from 2.0V to 5.0V, such as 2.5V to 4.5V, such as 2.5V to 4.2V. In such an embodiment, the plating voltage of the lithium carbon composite anode (charging of the battery) occurs at 0 to -100mV, such as 0 to -50mV, such as 0 to -40mV, such as 0 to -30m, such as 0 to -20mV, such as 0 to -10mV, such as 0 to -5mV, such as 0 to -1mV.

[0167] To evaluate the ability of the lithium-silicon-carbon anode to suppress lithium dendrite formation associated with galvanostatic charge-discharge cycling, the performance of a half-cell can be evaluated using lithium metal foil as the counter electrode and a lithium carbon composite as the active material contained within the working electrode. Specifically, electrochemical testing of the half-cell involves galvanostatic charge-discharge cycling, with the desired outcome being to minimize or eliminate short circuits due to lithium dendrite formation.

[0168] In the full-cell lithium silicon battery containing lithium-silicon-carbon composite, the strategy for conditioning the cell can be various as known in the art.For example, conditioning can be achieved by one or more charge and discharge cycles at various rates, for example at a rate slower than the desired cycling rate.As known in the art, the conditioning process can also include the step of unsealing the lithium ion battery, venting any gas generated during the conditioning process, and then resealing the lithium ion battery.

[0169] In lithium silicon carbon batteries including lithium-silicon-carbon composites, the cycling rate can vary as known in the art, e.g., from C / 20 to 20C, e.g., from C10 to 10C, e.g., from C / 5 to 5C. In certain embodiments, the cycling rate is C / 10. In certain embodiments, the cycling rate is C / 5. In certain embodiments, the cycling rate is C / 2. In certain embodiments, the cycling rate is 1C. In certain embodiments, the cycling rate is 1C with periodic rate reductions to slower rates, e.g., cycling at 1C and adopting a C / 10 rate every 20 cycles. In certain embodiments, the cycling rate is 2C. In certain embodiments, the cycling rate is 4C. In certain embodiments, the cycling rate is 5C. In certain embodiments, the cycling rate is 10C. In certain embodiments, the cycling rate is 20C.

[0170] In certain embodiments, the electrolyte may include various additives known to provide performance enhancements, such as fluoroethylene carbonate (FEC) or other related fluorinated carbonate compounds, or ester co-solvents such as methyl butyrate, vinylene carbonate, and other electrolyte additives known to improve electrochemical performance.

[0171] The coulombic efficiency of the lithium-silicon-carbon composites can be averaged, for example, over the fifth cycle or more when tested in half cells. In certain embodiments, the average efficiency of the composites with highly durable intercalation of lithium is greater than 0.9, i.e., greater than 90%. In certain embodiments, the average efficiency is greater than 0.95, i.e., greater than 95%. In other particular embodiments the average efficiency is 0.99 or more, such as 0.991 or more, such as 0.992 or more, for example 0.993 or more, such as 0.994 or more, for example 0.995 or more, such as 0.996 or more, for example 0.997 or more, such as 0.998 or more, such as 0.999 or more, such as 0.9991 or more, such as 0.9992 or more, for example 0.9993 or more, such as 0.9994 or more, for example 0.9995 or more, such as 0.9996 or more, for example 0.9997 or more, such as 0.9998 or more, such as 0.9999 or more.

[0172] Thermogravimetric analysis (TGA) can be employed to measure the relative amount of silicon impregnated within the pores of the porous carbon. TGA can be employed to assess the percentage of silicon present within the pores of the porous carbon relative to the total silicon present, i.e., the sum of the silicon within the pores and the silicon on the particle surface. When a silicon-carbon composite is heated in air, the sample is heated to a temperature of about 300°C to 500°C, at which point the silicon SiO 2 The sample then exhibits a mass increase reflecting an initial oxidation to SiO2, after which the sample exhibits a mass loss reflecting the resumption of conversion of silicon to SiO2, increasing toward an asymptotic value as the temperature approaches 1100 °C and the oxidation of silicon is complete. For this analysis, it is assumed that the minimum mass recorded for the sample heated from 800 °C to 1100 °C is the point at which carbon burn-off is complete. Any further mass increase corresponds to the oxidation of silicon to SiO2, and the total mass at the completion of oxidation is SiO2. 2 Thus, the proportion of unoxidized silicon after carbon combustion can be calculated as a percentage of the total amount of silicon by the following formula: Z=1.875x[(M1100-M) / M1100]x100 where M1100 is the mass of the sample when oxidation is complete at a temperature of 1100°C, and M is the minimum mass of the sample recorded when heated from 800°C to 1100°C.

[0173] Without being bound by theory, the temperature at which silicon oxidizes under TGA conditions is related to the length scale of the oxide coating on silicon due to the diffusion of oxygen atoms in the oxide layer. Thus, silicon present within the carbon pores will oxidize at a lower temperature than silicon deposited on the particle surfaces due to the necessarily thinner coating on these surfaces. In this way, the calculation of Z is used to quantitatively assess the fraction of silicon that is not impregnated within the pores of the porous carbon scaffold.

[0174] In preferred embodiments, Z is less than 30, Z is less than 20, Z is less than 15, Z is less than 10, Z is less than 5, Z is less than 4, Z is less than 3, Z is less than 2, Z is less than 1, or Z is less than 0.1. Such preferred levels of Z may be combined with other properties of the lithium-silicon-carbon composite, such as one, more, or all of the properties shown in Table 1. Alternatively, such preferred levels of Z may be combined with one, more, or all of the properties shown in Table 2.

[0175] Working Example Example 1. Properties of various carbon scaffold materials. Properties of various carbon scaffold materials are shown in Table 3. Exemplary carbon materials vary in properties such as total pore volume (e.g., 0.5-2 cm 3 / g and also vary in the proportion of micropores, mesopores and macropores).

[0176] Table 3. Properties of various carbon scaffold materials. [Table 3]

[0177] Example 2. Particle size distribution of various carbon scaffold materials. The particle size distribution of various carbon scaffolding materials was measured using a laser diffraction particle size analyzer as known in the art. Table 4 shows the data for Dv1, Dv10, Dv50, and Dv90, as well as Dv100, among others.

[0178] Table 4. Properties of various carbon scaffold materials. [Table 4]

[0179] Example 3. Preparation of silicon-carbon composite materials by CVI. A silicon-carbon composite (silicon-carbon composite 1) was fabricated by CVI using carbon scaffold 1 as follows: 0.2 grams of amorphous porous carbon was placed in a 2" x 2" ceramic crucible and placed in the center of a horizontal tube furnace. The furnace was sealed and continuously purged with nitrogen gas at 500 cubic centimeters per minute (ccm). The temperature of the furnace was increased at 20°C / min to a peak temperature of 450°C and allowed to equilibrate there for 30 minutes. At this point, the nitrogen gas was shut off and silane and hydrogen gas were introduced at flow rates of 50 ccm and 450 ccm, respectively, for a total residence time of 30 minutes. After the residence time was over, the silane and hydrogen were shut off and nitrogen was again introduced into the furnace to purge the furnace atmosphere. Simultaneously, the furnace heat was shut off and allowed to cool to ambient temperature. The finished silicon-carbon material was then removed from the furnace. This same CVI process can also be carried out on lithium-carbon composites or porous carbon frameworks containing lithium precursors.

[0180] Example 4. Analysis of various composite materials. Employing carbon scaffold samples as listed in Tables 3 and 4, the CVI method was employed in a static bed configuration as generally described in Example 3 to fabricate various silicon-carbon composite materials. These silicon-carbon samples were fabricated using various process conditions, including silane concentrations ranging from 1.25% to 100%, diluent gases ranging from nitrogen or hydrogen, and initial masses of carbon scaffolds ranging from 0.2 g to 700 g. A similar fabrication strategy can be achieved for the CVI processing of lithium-carbon composites or porous carbon frameworks containing lithium precursors.

[0181] The surface area of ​​the silicon-carbon composite was measured. The silicon-carbon composite was also analyzed by TGA to measure silicon content and Z. The silicon-carbon composite was also tested in a half-cell coin cell. The anode of the half-cell coin cell may include 60-90% silicon-carbon composite, 5-20% Na-CMC (as binder), and 5-20% Super C45 (as a conductivity enhancer), and the electrolyte may include 2:1 ethylene carbonate:diethylene carbonate, 1M LiPF6, and 10% fluoroethylene carbonate. The half-cell coin cell may be cycled at a C / 5 rate for 5 cycles at 25°C, followed by a C / 10 rate. The voltage may be cycled from 0V to 0.8V, or alternatively, from 0V to 1.5V. From the half-cell coin cell data, the maximum capacity can be measured, as well as the average coulombic efficiency (CE) over the cycle range from cycle 7 to cycle 20. The physicochemical and electrochemical properties of various silicon-carbon composite materials are shown in Table 5.

[0182] Table 5. Properties of various silicon-carbon materials [Table 5]

[0183] From these data, it is observed that all silicon-carbon samples with Z less than 10.0 have average coulombic efficiencies of 0.9941 or greater, while all silicon-carbon samples with Z greater than 10 (silicon-carbon composite sample 12 through silicon-carbon composite sample 16) have average coulombic efficiencies of 0.9909 or less. Without wishing to be bound by theory, the high coulombic efficiencies in silicon-carbon samples with Z<10 provide superior cycling stability in full-cell lithium-ion batteries. Looking further into the table, there is a surprising and unexpected finding that the combination of silicon-carbon composite samples with Z<10 and carbon scaffolds containing microporosity greater than 69.1 results in average coulombic efficiencies of 0.9969 or greater.

[0184] Thus, in a preferred embodiment, the lithium-silicon-carbon composite material comprises a Z of less than 10, such as a Z of less than 5, such as a Z of less than 3, such as a Z of less than 2, such as a Z of less than 1, such as a Z of less than 0.5, such as a Z of less than 0.1, or zero Z. Such preferred levels of Z may be combined with other properties of the lithium-silicon-carbon composite, such as one, more, or all of the properties shown in Table 1. Alternatively, such preferred levels of Z may be combined with one, more, or all of the properties shown in Table 2.

[0185] Example 5. Melt infiltration into porous carbon and CVI method for the fabrication of lithium-silicon-carbon composites. The porous carbon particles are placed in a metal or ceramic crucible and physically mixed with a portion of lithium metal in foil or powder form. The weight ratio Li:C is adjusted to partially fill the available pore volume of the carbon while allowing some residual voids (e.g., 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 w / w Li:C). The mixture is then heated under an inert atmosphere (e.g., argon, nitrogen, helium, or vacuum) to at least the melting point of lithium metal (e.g., 180°C, 190°C, 200°C, 220°C, 250°C, 300°C, 400°C, etc.). The mixture is allowed to dwell at the peak temperature for a period of time (e.g., 0.1 h, 1 h, 2 h, 5 h, 10 h, 24 h, etc.) to allow the molten lithium to infiltrate the carbon pore structure by capillary forces. At this point, a lithium-carbon composite is formed, which is then cooled to ambient temperature and removed for processing. The lithium present in the lithium-carbon composite may be reduced as generally described in this disclosure. The lithium-carbon composite may be further processed by CVI to incorporate silicon into one or more pores of the porous carbon framework.

[0186] In another embodiment, the lithium metal and porous carbon powders are kept separate in the same heated reactor environment, and the temperature is raised to very high temperatures (e.g., 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1350°C, etc.) to increase the vapor pressure of the molten lithium. This promotes the vapor growth of lithium metal within the pore structure of the carbon by capillary condensation. The Li:C ratio is therefore controlled by the residence time at the peak temperature (e.g., 0.1 hours, 1 hour, 2 hours, 5 hours, 10 hours, 24 hours, etc.).

[0187] In yet another embodiment, the lithium metal source is in the form of an electrode / target in a plasma-enhanced physical vapor deposition apparatus, with the porous carbon acting as the counter electrode. Synthesis is performed by applying a voltage bias between the electrodes under a partial pressure of argon gas. This promotes the evaporation of lithium metal by ion bombardment, resulting in the deposition of lithium metal on the porous carbon. The Li:C ratio can be controlled by residence time, similar to the above embodiment.

[0188] Example 6. Method of melt infiltration on silicon-carbon composite to produce lithium-silicon-carbon composite. Silicon-carbon composite particles are placed in a metal or ceramic crucible and physically mixed with a portion of lithium metal in foil or powder form. The weight ratio of Li:silicon-carbon composite is adjusted to partially fill the available pore volume of the carbon, allowing for some residual porosity (e.g., 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 w / w Li:silicon-carbon composite). The mixture is then heated under an inert atmosphere (e.g., argon, nitrogen, helium, or vacuum) to at least the melting point of lithium metal (e.g., 180°C, 190°C, 200°C, 220°C, 250°C, 300°C, 400°C, etc.). The mixture is allowed to dwell at the peak temperature for a period of time (e.g., 0.1 h, 1 h, 2 h, 5 h, 10 h, 24 h, etc.) to allow the molten lithium to infiltrate the carbon pore structure by capillary forces. At this point a lithium-silicon-carbon composite is formed, which is then cooled to ambient temperature and removed for processing.

[0189] In another embodiment, the lithium metal and silicon-carbon composite are kept separate in the same heated reactor environment, and the temperature is raised to very high temperatures (e.g., 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1350°C, etc.) to increase the vapor pressure of the molten lithium. This promotes the vapor growth of lithium metal within the pore structure of the carbon by capillary condensation. The Li:C ratio is therefore controlled by the residence time at the peak temperature (e.g., 0.1 hr, 1 hr, 2 hr, 5 hr, 10 hr, 24 hr, etc.).

[0190] In yet another embodiment, the lithium metal source is in the form of an electrode / target in a plasma-enhanced physical vapor deposition apparatus, with the porous carbon acting as the counter electrode. Synthesis is performed by applying a voltage bias between the electrodes under a partial pressure of argon gas. This promotes the evaporation of lithium metal by ion bombardment, resulting in the deposition of lithium metal on the porous carbon. The Li:C ratio can be controlled by residence time, similar to the above embodiment.

[0191] The lithium present in the lithium-silicon-carbon composite can be reduced as generally described in this disclosure.

[0192] Example 7. Method of solution infiltration into a porous carbon framework to synthesize lithium-silicon-carbon composites. In a typical embodiment, a solution of naphthalene in an anhydrous aprotic ether solvent (e.g., tetrahydrofuran, dimethoxyethane, diethyl ether, etc.) is prepared in an inert gas environment (e.g., argon, nitrogen, helium, etc.). A portion of lithium metal (1:1 molar ratio to naphthalene) is added to the solution in the form of foil, pellets, or powder while stirring or sonicating. The lithium metal is completely dissolved to give a clear green solution. Porous carbon is then added to the solution in the desired Li:C ratio as shown in Example 5. The solvent and naphthalene are then removed from the mixture by evaporation after solvent exchange with a non-ethereal aprotic solvent (e.g., toluene, acetonitrile, etc.) to obtain a dry lithium-carbon composite material, which can be removed for treatment with silane CVI to produce a lithium-silicon-carbon composite. Prior to CVI treatment, the lithium present in the lithium-carbon composite can be reduced as generally described in this disclosure.

[0193] In another preferred embodiment, the mixture is heated to a temperature (e.g., 220° C. or higher) that promotes evaporation of both the naphthalene and the solvent species. No additional solvent is used, leaving only the lithium-carbon composite material. The lithium-carbon composite as described in this example can then be further processed by silicon CVI according to the procedures generally described herein to obtain a lithium-silicon-carbon composite. The lithium content present in the lithium-silicon-carbon composite can be reduced as generally described in this disclosure.

[0194] Example 8. Method of solution infiltration into silicon-carbon composite to synthesize lithium-silicon-carbon composite. In a typical embodiment, a solution of naphthalene in an anhydrous aprotic ether solvent (e.g., tetrahydrofuran, dimethoxyethane, diethyl ether, etc.) is prepared in an inert gas environment (e.g., argon, nitrogen, helium, etc.). A portion of lithium metal (1:1 molar ratio to naphthalene) is added to the solution in the form of foil, pellet, or powder while stirring or sonicating. The lithium metal is completely dissolved to give a clear green solution. Silicon-carbon composites produced by CVI are then added to the solution in the desired Li:C ratio as shown in Example 6. The solvent and naphthalene are then removed from the mixture by evaporation after solvent exchange with a non-ethereal aprotic solvent (e.g., toluene, acetonitrile, etc.) to obtain a dry lithium-carbon composite material.

[0195] In another preferred embodiment, the mixture is heated to a temperature (e.g., 220° C. or higher) that promotes evaporation of both the naphthalene and the solvent species, leaving only the lithium-carbon composite material and no additional solvent.

[0196] The lithium present in the lithium-silicon-carbon composite can be reduced as generally described in this disclosure.

[0197] Example 9. Gas phase method for the synthesis of lithium carbon composite. Lithium is created in the pores of the porous carbon scaffold by exposing the porous carbon particles to a lithium-containing precursor gas at high temperature to achieve lithium chemical vapor infiltration (CVI). For example, the high temperature is above the boiling point of the lithium-containing precursor to achieve its gasification. Exemplary lithium precursors in this regard include, but are not limited to, lithium bis(trimethylsilyl)amide, lithium acetylsalicylate, lithium amide, lithium bromide, lithium tetrahydride, lithium chloride, lithium hydride, lithium hydroxide, and mixtures thereof. The lithium-containing precursor gas can be mixed with other inert gases, such as nitrogen gas, hydrogen gas, argon gas, helium gas, or combinations thereof.

[0198] The temperature and time of the treatment may vary, for example the temperature may be between 50°C and 900°C, such as between 50°C and 250°C, for example between 50°C and 100°C, for example between 75°C and 150°C, for example between 100°C and 150°C, for example between 150°C and 200°C, for example between 200°C and 250°C, for example between 250°C and 300°C, for example between 300°C and 350°C, for example between 300°C and 400°C, for example between 350°C and 450°C, for example between 350°C and 400°C, for example between 400°C and 500°C, for example between 500°C and 600°C, for example between 600°C and 700°C, for example between 700°C and 800°C, for example between 800°C and 900°C, for example between 600°C and 1100°C.

[0199] The mixed gas comprises 0.1-1% gaseous lithium precursor and the remaining inert gas. Alternatively, the mixed gas comprises 1%-10% lithium precursor and the remaining inert gas. Alternatively, the mixed gas comprises 10%-20% lithium precursor and the remaining inert gas. Alternatively, the mixed gas comprises 20%-50% lithium precursor and the remaining inert gas. Alternatively, the mixed gas may comprise more than 50% lithium precursor and the remaining inert gas. Alternatively, the gas may be essentially 100% lithium precursor gas. The pressure of the CVI process may vary. In some embodiments, the pressure is atmospheric. In some embodiments, the pressure is less than atmospheric. In some embodiments, the pressure is greater than atmospheric. The lithium-carbon composite as described in this example may then be further processed by silicon CVI according to the procedures generally described herein to obtain a lithium-silicon-carbon composite.

[0200] In a related embodiment, lithium is added to the silicon-carbon composite material by exposing the silicon-carbon composite particles to a lithium-containing precursor gas at elevated temperature to achieve lithium chemical vapor infiltration (CVI).

[0201] By exposing the porous carbon particles to a lithium-containing precursor gas at an elevated temperature to achieve lithium chemical vapor infiltration (CVI) within the pores of the porous carbon scaffold, for example, to achieve gasification, the elevated temperature is above the boiling point of the lithium-containing precursor.

[0202] Example 10. Addition of alloying species for the synthesis of lithium carbon composites. As known in the art, lithium metal may in some cases be alloyed with other elements that form eutectic mixtures with lower melting points (<180° C.). These eutectic mixtures may be utilized to facilitate easier direct formation / precipitation of lithium metal within the porous carbon structure. In one such embodiment, first, an alloying agent (e.g., silver) is added to the porous carbon scaffold in the form of a solution (e.g., 0.1 M silver nitrate solution) containing the alloy precursor. The solution is added to the dried porous carbon powder by methods known in the art as incipient wetness at low relative concentrations (e.g., 0.1%, 1%, 2%, 5%, or 10% w / w Ag:C). The water solvent is then removed by evaporation, causing the alloy precursor to decompose / reduce to a metal neutral oxidation state (i.e., silver metal) in the form of discrete nanoparticles (e.g., 1-50 nm in diameter) throughout the carbon pore structure. This Ag / C composite can be used as a host material for lithium metal formation, as described in the synthesis examples above. In the case of Example 1, the eutectic point of about 0.1 w / w Li / Ag alloy is at a lower temperature than lithium metal itself (i.e., 143°C compared to 180°C for pure lithium), so the melt infiltration step of lithium metal in the carbon pores occurs preferentially where the silver nanoparticles are present. When the eutectic Li / Ag alloy reaches the lithium saturation point, solid lithium precipitates from the eutectic melt, thus inducing the bulk of lithium metal formation in the carbon pore structure where the silver nanoparticles were originally present. In another embodiment, such as in the case of Example 3, the silver nanoparticles in the carbon pore structure can act as catalytic seed particles for the precipitation and subsequent alloying of lithium metal from the lithium precursor gas during CVI.

[0203] Example 11. Reduction of lithium salts for the synthesis of lithium carbon composites. To decompose the lithium salt into lithium metal, a reducing agent (e.g., H 2 , NaBH 4 Porous carbon particles are heated at high temperatures with or without lithium salts (e.g., LiF, LiCl, LiNO, etc.) in the presence or absence of oxalic acid, glucose, or carbon. 3 , Li 2 CO 3 , LiI, LiBr, LiAlH4, LiOH, Li 2 O, LiO 2 , Li 3 In an embodiment, lithium is generated in the pores of the porous carbon scaffold by mixing with a solvent (e.g., tetrahydrofuran, propylene carbonate, acetone, etc.) to allow lithium salt to flow / absorb more easily into the nanopores of the porous carbon scaffold. The reduction temperature and treatment time can be varied, for example, the temperature can be varied from 0°C to 900°C, e.g., 0°C to 250°C, e.g., 250°C to 300°C, e.g., 300°C to 350°C, e.g., 300°C to 400°C, e.g., 350°C to 450°C, e.g., 350°C to 400°C, e.g., 400°C to 500°C, e.g., 500°C to 600°C, e.g., 600°C to 700°C, e.g., 700°C to 800°C, e.g., 800°C to 900°C, e.g., 600°C to 1100°C. The solvent / salt mixture can include 0.1 to 1% lithium salt and the remaining liquid solvent. Alternatively, the solvent / salt mixture may include 1%-10% lithium salt and the remainder liquid solvent. Alternatively, the solvent / salt mixture may include 10%-20% lithium salt and the remainder liquid solvent. Alternatively, the solvent / salt mixture may include 20%-50% lithium salt and the remainder liquid solvent. Alternatively, the solvent / salt mixture may include more than 50% lithium salt and the remainder liquid solvent. Alternatively, the solvent / salt may be essentially 100% lithium salt. The pressure in the reduction process may vary. In some embodiments, the pressure is atmospheric. In some embodiments, the pressure is less than atmospheric. In some embodiments, the pressure is greater than atmospheric.

[0204] Example 12. Electrochemical method for forming lithium carbon composites. In one embodiment, the lithium carbon composite is used in an electrolytic cell that is charged with a lithium salt (e.g., LiPF 6 , LiFSI, LiTFSI, LiCl, LiBr, LiI, LiNO 3 It can be synthesized by an electroplating mechanism, where a porous carbon working electrode (prepared by slurry casting on a copper foil or nickel sheet current collector) and a lithium metal counter electrode are assembled, separated from each other, in a liquid electrolyte containing an anhydrous organic solvent (e.g., propylene carbonate, ethylene carbonate, 1,3-dioxolane, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, etc.). A negative voltage bias (e.g., -1V, -2V, -3V, -4V, -5V, -6V, etc.) is applied to promote the reduction of Li+ at the porous carbon electrode. The amount of charge transferred (Ah) is used to track the Li metal loading, and then the applied voltage is stopped once the desired Li loading is achieved. The lithium carbon electrode can then be used as the anode in a lithium ion battery.

[0205] A similar embodiment to that described above, in which the porous carbon electrode is prepared on a roll-to-roll coater and then transferred to an electrolyte bath (described above) housed in an inert atmosphere, a negative voltage bias is applied as in the embodiment described above, and lithium plating occurs while the electrode is continuously moving on the rollers. The extent of lithium metal loading is thus determined by the transport speed of the roll-to-roll machine. Additionally, the electrolyte bath may contain dissolved polymers (e.g., polyacrylonitrile, polyvinylidene fluoride, polydopamine, etc.) such that when the electrode is removed from the bath and subsequently dried, a polymer film is left on the electrode surface acting as a barrier to the atmosphere, thus minimizing oxidation of the lithium metal formed on the porous carbon.

[0206] In an alternative preferred embodiment, lithium electroplating is performed using a porous carbon electrode (described above) as the anode and a conventional Li-containing transition metal oxide as known in the art (e.g., LiFePO 4 , LiCoO 2 The Lithium electroplating can be performed in-situ in an as-assembled Li-ion battery, with the cathode (NMC111, NMC532, NMC622, etc.) acting as the cathode. Lithium electroplating occurs when the battery is charged to 100% state-of-charge operating voltage (e.g., 4.2V). In this "anode-free" configuration, the Li+ source is the cathode. When the battery is discharged, the process is reversed (Li+ stripping from the porous carbon electrode). This embodiment is preferred as it eliminates the need to handle reactive lithium metal in an environment outside the battery, and further improves the energy density of the battery, since the cathode serves as the only source of Li+ in the system.

[0207] Example 13. Terminal coating method for lithium carbon composite. Due to the high reactivity of lithium metal in atmospheric conditions (e.g., oxidation reactions with water, oxygen, carbon dioxide), it may be necessary to coat / protect the surface of the lithium using the terminal coating methods described herein. In one embodiment, after synthesis of the LCC as described in Examples 1-6, the composite is heated to a temperature (e.g., 400-1000°C) to promote decomposition of a hydrocarbon gas (e.g., acetylene, propylene, ethylene, methane, propane, propadiene / propylene, etc.). At the peak temperature, the hydrocarbon gas is introduced into the heated chamber containing the LCC material, and a chemical vapor deposition reaction occurs that deposits carbon on the surface of the LCC material according to the reaction equation CxHy=>C+H2. The thickness of the coating can be controlled by the residence time that the hydrocarbon gas is present (e.g., 0.1hr-6hr). The silicon is then protected from oxidation under atmospheric conditions by applying a carbon coating. In another embodiment, the LCC material may be coated with a polymer (eg, polydopamine, polyacrylonitrile, polyaniline, polypyrrole, etc.) to enable low temperature (eg, <200° C.) processing.

[0208] Example 14. Surface functionality methods and metrics. The surface functionality of the composite material of the present disclosure composed of carbon and lithium can be modified to obtain desired electrochemical properties. One such property of a particulate composite material is the concentration of atomic species at the surface of the composite material relative to the interior of the composite material. Such differences in the concentration of atomic species at the surface vs. the interior of a particulate composite material can be measured, for example, by X-ray photoelectron spectroscopy (XPS), as known in the art. For example, the concentration of Li:C at the surface (defined as 5 nm from the edge of the particulate surface) can be measured by this method. In some embodiments, the ratio of Li:C at the surface ranges from about 0.1:1 to 10:1. In other particular embodiments, the ratio of Li:C at the surface is about 0:1. In other embodiments, the ratio of Li:C at the surface is about 1:0. In another example, the ratio of Li:O at the surface ranges from about 0:1 to 1:0.

[0209] Another property that can predict surface functionality is the pH of the LCC composite material. Composite materials of the present disclosure include pH values ​​ranging from less than 1 to about 14, such as less than 5, 5-8, or greater than 8. In some embodiments, the pH of the composite material is less than 4, less than 3, less than 2, or even less than 1. In other embodiments, the pH of the composite material is about 5-6, about 6-7, about 7-8, 8-9, or 9-10. In still other embodiments, the pH is high and the pH of the composite material ranges from greater than 8, greater than 9, greater than 10, greater than 11, greater than 12, or even greater than 13.

[0210] Other methods and standards for measuring carbon structure include X-ray diffraction (XRD) and Raman spectroscopy. With respect to XRD, the graphiticity of a carbon material can be assessed by monitoring the peak intensities at various 2q corresponding to various Miller indices. Without being bound by theory, the diffraction lines of graphite are classified into various groups such as 00l, hk0, and hkl indices, mainly due to the strong anisotropy of the structure. One such species is 002, which corresponds to the basal plane of graphite and is located at 2θ of about 26°; this peak is prominent in highly graphitic carbon materials. Carbon materials with a low extent of graphiticity and small crystallite size can be characterized by very broad 00l lines (e.g., 002) and shifts (e.g., 2θ of about 23°) and asymmetric hk lines (e.g., 10 corresponding to 2θ of about 43°) due to a low degree of stacking layers. Furthermore, the crystallite size (Lc) can be calculated from the 002 line and the crystallite size (La) can be calculated from the 100 line using the Scherrer equation.

[0211] Regarding Raman spectroscopy, this method can also be employed to evaluate the graphiticity of carbon, as reported in the art. The position, shape, and size of the Raman D and G bands are known in the art to calculate La values ​​from the Tuinstra Koenig (TK) model for grain sizes greater than 2 nm, or from the Ferrari (FR) model when the TK model calculates grain sizes less than 2 nm (Ferrari, AC, & Robertson, J. (1970); Tuinstra, F., & Koening, JL (1970). Raman spectrum of graphite. The Journal of Chemical Physics, 53(3), 1126-1130). Interpretation of Raman spectra of disordered and amorphous carbon. Physical Review B, 61(20), 14095-14107). These models provide a measure of disorder in carbon materials and represent the length of the graphene crystallite sheets in the carbon materials.

[0212] Yet another analytical method is the measurement of oxygen, nitrogen and hydrogen using an inert gas fusion apparatus. Lithium-carbon composite materials can contain various amounts of carbon, oxygen, hydrogen and nitrogen, which are measured by an inert gas fusion apparatus (LECO ONH 836) known in the art. The lithium-carbon composite samples are flash heated in a graphite arc furnace to about 3000°C with flowing helium gas. The oxygen in the samples is determined by CO 2 and / or CO, which is carbothermally reduced into a helium gas stream and quantified downstream using an infrared spectrometer. 2 is generated from the sample in the form of H 2 O, which is also quantified by IR spectrometry. Finally, nitrogen is converted to N 2 is generated from the sample in the form of and is quantified using a thermal conductivity detector.

[0213] In some embodiments, the lithium-carbon composite material has a nitrogen content in the range of 0-90%, such as 0.1-1%, for example 1-3%, such as 1-5%, for example 1-10%, for example 10-20%, for example 20-30%, for example 30-90%. In some embodiments, the oxygen content is in the range of 0-90%, such as 0.1-1%, for example 1-3%, for example 1-5%, for example 1-10%, for example 10-20%, for example 20-30%, for example 30-90%.

[0214] Example 15. Stability of lithium carbon composites under ambient conditions. The instability of lithium metal under ambient conditions is known in the art. The present disclosure provides lithium protected within a porous carbon scaffold, optionally with a terminal coating applied to the composite particles. This protection can be explained in terms of the confinement of lithium within the carbon scaffold, which manifests itself as reduced or eliminated reactivity in air (oxygen), stability in contact with other battery components (chemical), stability during operation (electrochemical), and suppression of dendrites during battery cycling. For example, criteria such as onset time or severity of reaction with organic solvents can be used to determine the degree of reactivity of lithium within the carbon scaffold. 2 Alternatively, the stability can be measured by the occurrence and / or total amount. Alternatively, the onset time or severity of tarnishing / color change / oxidation of lithium-carbon in air can be measured. Alternatively, the stability can be evaluated by measuring the mass gain due to oxidation of lithium in the composite with TGA / DSC. Furthermore, DSC is also known to provide information on the melting point of lithium, the alteration of which provides information on the stability and / or placement of lithium within the carbon scaffold porosity. Alternatively, the stability can be measured in half-cells vs. lithium metal, measuring the number of galvanostatic cycles until dendrite failure, i.e., shorting of the half-cell. Alternatively, the stability can be evaluated by small angle X-ray scattering (SAXS) or neutron scattering, measuring the distribution and size of lithium within the pores of the porous carbon.

[0215] Example 16. Solution infiltration method for producing lithium-silicon alloy-carbon composite material. In an exemplary solution immersion method, 0.2 grams of Li metal is dissolved as a 1 molar solution containing 3.66 grams of naphthalene and 28.6 mL of tetrahydrofuran (THF) under inert (argon) atmosphere with vigorous stirring until a dark green translucent solution is obtained. 1.0 grams of silicon-carbon composite is then added to the 28.6 mL of lithium naphthalene / THF solution and immersed for 15 minutes. Lithiation proceeds by chemical reaction, individually alloying with silicon, intercalating with carbon, and converting the oxide components of the silicon-carbon composite. After immersion, the lithium-alloyed silicon-carbon composite is recovered after five centrifugation / washing steps with anhydrous THF, and then dried under vacuum.

[0216] X-ray diffraction spectra of the as-is and lithium-alloyed silicon-carbon composites are shown in Figure 1. Both spectra were collected without air exposure by covering the composite with Kapton tape in an argon-filled glove box. The pure silicon-carbon composite exhibits spectra characteristic of amorphous silicon and carbon. The lithium-alloyed silicon-carbon composite remains amorphous with only a slight increase in intensity in the 20 and 45 2θ regions. This suggests that no inert crystalline lithium phases such as lithium hydroxide, oxide, or carbonate were formed as a result of the solution immersion process.

[0217] Subsequent XRD analysis was performed without the use of Kapton tape to understand the oxidation behavior of the lithium alloyed silicon-carbon composite under ambient atmosphere. The results shown in Figure 2 indicate that there was little change after only about 40 minutes of air exposure, but after about 24 hours of air exposure, there was a strong appearance of crystalline lithium carbonate (ICDD PDF# 009-0359).

[0218] The elemental composition of the silicon-carbon and lithium alloyed silicon-carbon composites was analyzed by X-ray photoelectron spectroscopy (XPS) and the results are shown in Table 6. Due to the nature of the technique, the samples were exposed to air prior to analysis and the elemental composition represents only the material surface to a depth of approximately 10 nanometers. The pure silicon-carbon composite shows characteristic amounts of silicon, carbon, and oxygen, while the lithium alloyed-carbon composite shows a high atomic fraction of lithium with a correspondingly low silicon signal. This suggests that exposure to air results in the dealloying of lithium and the subsequent formation of the LixOyCz moiety (e.g., LiOH, Li 2 O, Li 2 CO 3 This suggests that significant oxide film formation occurs, leading to the formation of

[0219] Table 6. X-ray photoelectron spectroscopy results of pure silicon–carbon composites and lithium-alloyed silicon–carbon composites. [Table 6]

[0220] Example 17. Electrochemical testing of lithium-silicon alloy-carbon composite electrodes prepared by solution immersion processing. Silicon-carbon composite electrodes were prepared as an aqueous slurry containing silicon-carbon composite, Super C45 as conductive additive, and sodium polyacrylate (Na-PAA) as binder in a weight ratio of 80:10:10, respectively. The slurry was applied onto copper foil as a current collector and dried at 80 °C for about 30 min, followed by vacuum drying at 120 °C for about 2 h, and then transferred into an argon-filled glove box for cell assembly.

[0221] Electrodes approximately 0.5 inches in diameter were punched from the coated sheets and then immersed in a 1M Li-biphenyl in THF solution for 30 minutes to allow for lithium alloying by solution immersion. The lithium-alloyed silicon-carbon composite electrodes were recovered from the solution and the residual Li-biphenyl moiety was removed using pure THF, after which they were dried at ambient temperature (approximately 27°C) under an inert atmosphere. The lithium-alloyed silicon-carbon composite electrodes were prepared using Celgard 2325 tri-layer polyethylene / polypropylene / polyethylene as the separator, Li metal foil as the counter electrode, and 1M LiPF in 2:1 (w / w) ethylene carbonate:diethyl carbonate with 10 wt% fluoroethylene carbonate as the base electrolyte. 6 The half-cell was assembled into a CR2032 half-cell using a galvano / potentiostat setup. The half-cell was then rested at open circuit voltage (OCV) for 6 hours, measuring 0.573 V vs Li / Li+. It was then galvanostatically discharged (constant current) at a rate of approximately 150 mAh / g (C / 10), ramped down to 0.005 V vs Li / Li+, and charged (discharged) at the same constant current to 1.5 V vs Li / Li+. This constitutes one cycle. From this cycle, the first cycle efficiency (FCE) and gravimetric capacity were measured. The results are shown in Table 2. Two more discharge / charge cycles at C / 10 were performed, followed by seven cycles at 300 mAh / g (C / 5).

[0222] FIG. 3 shows the cycling stability performance of a silicon-carbon composite and two lithium-alloyed silicon-carbon composites prepared using a variation of the method outlined in Example 17. The lithium alloying mechanism can improve the coulombic efficiency and capacity retention between cycles. Table 7 summarizes the synthesis conditions and electrochemical test results for various lithium-alloyed silicon-carbon composites prepared according to Example 17. Except for Samples 17-C1 and C2 (controls that were not subjected to the infiltration process), for these samples the lithium salt was either lithium naphthalene or lithium biphenyl, the temperature of infiltration was 25-40°C, and the carrier solvent was either dimethoxymethane or tetrahydrofuran.

[0223] Table 7. Synthesis conditions and electrochemical properties of lithium-alloyed silicon-carbon composites prepared in electrode form. [Table 7]

[0224] Embodiment Embodiment 1. A particulate material comprising a plurality of composite particles, the composite particles comprising: (i) a porous carbon framework; (ii) a plurality of nanoscale amorphous elemental silicon domains located within the micropores and / or mesopores of the porous carbon framework; and (iii) a plurality of lithium domains comprising lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof.

[0225] Embodiment 2. The porous carbon framework is 0.5 cm 3 2. The composite of embodiment 1, comprising a pore volume of 0.1 mm or more per 100 μm / g, a DPv80 of 2 nm or less, a DPv99 of 50 nm or less, and a Dv50 of 0.1 to 50 microns.

[0226] Embodiment 2. The porous carbon framework is 0.5 cm 32. The composite of embodiment 1, comprising a pore volume of 0.1 mm or more per 100 μm / g, a DPv70 of 2 nm or less, a DPv90 of 50 nm or less, and a Dv50 of 0.1 to 50 microns.

[0227] Embodiment 3. The porous carbon framework is 0.5 cm 3 2. The composite of embodiment 1, comprising a pore volume of 0.1 mm or more per 100 μm / g, a DPv80 of 2 nm or less, a DPv99 of 50 nm or less, and a Dv50 of 0.1 to 50 microns.

[0228] Embodiment 4. The porous carbon framework is 0.6 cm 3 The composite according to any one of the first to third embodiments, comprising a pore volume of at least 1000 μm / g.

[0229] Embodiment 5. The composite of any one of embodiments 1 to 4, wherein the silicon content is 30 to 70% and the lithium content is 0.1 to 20%.

[0230] Embodiment 6. The composite of any one of embodiments 1 to 5, wherein the particles are spherical in shape.

[0231] Embodiment 7. The composite of any of embodiments 1-6, wherein the particle size distribution comprises two or more modes.

[0232] Embodiment 8. The composite of any one of embodiments 1 to 7, wherein the particle size distribution of the composite comprises multiple modes.

[0233] Embodiment 9. The composite of any of embodiments 1-8, wherein the particle size distribution of the composite includes a left skew.

[0234] Embodiment 10. The composite of any of embodiments 1-8, wherein the particle size distribution of the composite includes a right skew.

[0235] Embodiment 11. The composite of any of the embodiments 1-10, wherein the composite particles are surface-coated with an amorphous carbon layer, for example, by chemical vapor deposition of a hydrocarbon (e.g., acetylene, propylene, methane, propane, ethylene, and combinations thereof).

[0236] Embodiment 12. The composite of any of the embodiments 1 to 10, wherein the composite particles are passivated on the surface by chemical vapor passivation using a hydrocarbon (e.g., acetylene, propylene, methane, propane, ethylene, and combinations thereof).

[0237] Embodiment 13. The composite of any of the embodiments 1 to 10, wherein the composite particles are surface-coated with an organic polymer layer, such as polydopamine, polyacrylonitrile, polyethylene glycol, polyvinylidene fluoride, polyaniline, polyacrylic acid, polysulfide, and combinations thereof.

[0238] Embodiment 12. Composite particles are prepared by vapor-phase atomic layer deposition (ALD) of a metal oxide, such as Al 2 O 3 , TiO 2 , ZrO 2 , Li 2 O, ZnO, SiO 2 and combinations thereof coated on a surface of the composite of any of the first to tenth embodiments.

[0239] Embodiment 13. Composite particles are prepared by sol-gel processing of metal oxides, such as B 2 O 3 , Al 2 O 3 , LiAlO 2 , TiO 2 , Li 2 ZrO 3 , ZrO 2 , Li 2 O, ZnO, SiO 2 , LiNbO 3, Li 2 WO 4 11. The composite of any one of the first to tenth embodiments, having a surface coated with, or a combination thereof.

[0240] Embodiment 14. The composite of any one of embodiments 1 to 13, wherein the composite comprises a capacity of greater than 900 mAh / g.

[0241] Embodiment 15. The composite of any one of embodiments 1 to 13, wherein the composite comprises a capacity of greater than 1300 mAh / g.

[0242] Embodiment 16. The composite of any one of embodiments 1 to 13, wherein the composite comprises a capacity of greater than 1600 mAh / g.

[0243] Embodiment 17. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9970 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0244] Embodiment 18. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9980 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0245] Embodiment 19. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9985 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0246] Embodiment 20. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9990 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0247] Embodiment 21. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9995 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0248] Embodiment 22. The composite of any of the embodiments of embodiments 1 to 16, comprising an average coulombic efficiency of greater than 0.9999 measured on a half-cell at a C / 10 rate cycling from 5 mV to 0.8 V over a cycle range of cycle 7 to cycle 20.

[0249] Embodiment 23. The composite of any one of embodiments 1 to 22, wherein Z is less than 10.

[0250] Embodiment 24. (i) Micropores and mesopores, and 0.5 cm 3 (ii) a silicon content of 30% to 70%; and (iii) a surface coating layer applied at least partially thereto, the surface coating layer forming a surface coating on a surface region of the silicon-carbon composite comprising at least one or more of the elements B, C, Si, Li, Al, Ti, Zr, Nb, and W.

[0251] Embodiment 25. The silicon-carbon composite material of embodiment 24, wherein the surface coating layer has a thickness in the range of 0.1 nm to 1000 nm.

[0252] Embodiment 26. The silicon-carbon composite material of embodiment 24 or 25, wherein the surface coating layer comprises a metal oxide.

[0253] Embodiment 27. A silicon-carbon composite material according to any of embodiments 24-26, wherein the surface coating region covers at least 50% of the surface area of ​​the silicon-carbon composite.

[0254] Embodiment 28. A silicon-carbon composite material according to any of embodiments 24 to 27, comprising a further coating on the surface coating layer, whereby the surface coating layer and the further coating form a surface coating region.

[0255] Embodiment 29. The silicon-carbon composite material of embodiment 28, wherein the further coating is a carbon coating.

[0256] 30. Surface area is 30 m 2 30. The silicon-carbon composite material of any one of embodiments 24 to 29, wherein the silicon-carbon composite material has a molecular weight of less than 1.0 μm / g.

[0257] 31. Surface area is 20 m 2 30. The silicon-carbon composite material of any one of embodiments 24 to 29, wherein the silicon-carbon composite material has a molecular weight of less than 1.0 μm / g.

[0258] Embodiment 32. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to form a lithium-silicon-carbon composite material; The process includes:

[0259] Embodiment 33. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to form a lithium-silicon alloy silicon-carbon composite material; The process includes:

[0260] Embodiment 34. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. heating the silicon-carbon composite material in the presence of a lithium-containing precursor to produce a lithium-silicon alloy silicon-carbon composite material, wherein the lithium also contains non-silicon alloy domains; The process includes:

[0261] Embodiment 35. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; The process includes:

[0262] Embodiment 36. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a lithium-silicon alloy-carbon composite material; The process includes:

[0263] Embodiment 37. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the carbon framework in the presence of a lithium-containing precursor to form a lithium-carbon composite material; and c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework to provide a lithium-silicon alloy-carbon composite material, wherein the lithium also contains non-silicon-alloy domains; The process includes:

[0264] Embodiment 38. The process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein the lithium-containing precursor is introduced in gaseous form.

[0265] Embodiment 39. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein the lithium-containing precursor is introduced in solid or liquid form and converted to gaseous form under conditions for carrying out the alloying process.

[0266] Embodiment 40. A process for producing a composite material comprising a plurality of particles of embodiment 39, wherein the gasified lithium-containing precursor is mixed with an inert gas.

[0267] Embodiment 41. The process for producing a composite material comprising a plurality of particles of embodiment 40, wherein the inert gas comprises nitrogen, argon, hydrogen, or a combination thereof.

[0268] Embodiment 42. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein the temperature for introducing lithium is 100°C to 1700°C or less.

[0269] Embodiment 43. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein the lithium precursor is lithium and the temperature is at least 1330° C.

[0270] Embodiment 44. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein the lithium precursor is heated to a temperature at least corresponding to the boiling point.

[0271] Embodiment 45. The process for producing a composite material comprising a plurality of particles according to embodiment 44, wherein the lithium precursor is lithium bis(trimethylsilyl)amide, lithium acetylsalicylate, lithium amide, lithium bromide, lithium tetrahydride, lithium chloride, lithium hydride, lithium hydroxide, or a combination thereof.

[0272] Embodiment 46. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein a silicon CVI process is followed by a lithium CVI process.

[0273] Embodiment 47. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 37, wherein silicon and lithium are simultaneously introduced according to a co-CVI process.

[0274] Embodiment 48. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 32 to 47, wherein the conversion of the lithium-containing precursor to lithium can be achieved by a variety of methods, such as chemical or electrochemical reduction.

[0275] Embodiment 49. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. melting a lithium precursor in the presence of a silicon-carbon composite material to form a lithium-silicon-carbon composite material; The process includes:

[0276] Embodiment 50. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. melting a lithium precursor in the presence of a silicon-carbon composite material to form a lithium-silicon alloy-carbon composite material; The process includes:

[0277] Embodiment 51. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; and c. melting a lithium precursor in the presence of a silicon-carbon composite material to produce a lithium-silicon alloy-carbon composite material, wherein the lithium also contains non-silicon alloy domains; The process includes:

[0278] Embodiment 52. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework in the presence of a silicon-containing gas and a lithium precursor at an elevated temperature above the melting point of the lithium precursor to impregnate both silicon and lithium into one or more pores of the porous carbon framework; and c. the lithium in the composite comprises lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof; The process includes:

[0279] Embodiment 53. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. melting a lithium precursor in the presence of a carbon framework material to produce a lithium-silicon composite material; c. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and d. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof; The process includes:

[0280] Embodiment 54. A process for producing a composite material comprising a plurality of particles, as described in any one of embodiments 49 to 53, wherein the temperature for achieving melt infiltration is 25°C to 1000°C.

[0281] Embodiment 55. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 49 to 53, wherein the temperature for achieving lithium infiltration is at least the melting point of the lithium precursor.

[0282] Embodiment 56. The process for producing a composite material comprising a plurality of particles according to embodiment 55, wherein the lithium precursor is lithium metal.

[0283] Embodiment 57. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 49 to 53, wherein the lithium precursor is lithium carbonate, lithium acetate, lithium amide, lithium bromide, lithium tetrahydride, lithium peroxide, lithium chloride, lithium fluoride, lithium hydride, lithium hydroxide, lithium hydrogen sulfate, lithium dihydrogen phosphate, lithium nitrate, lithium phosphate, lithium nitride, lithium sulfate, lithium sulfide, lithium disulfide, lithium sulfite, lithium aluminum alloy, lithium aluminum copper alloy, lithium tin alloy, lithium silicon alloy, or a combination thereof.

[0284] Embodiment 58. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 49 to 53, wherein the conversion of the lithium-containing precursor to lithium is achieved by chemical or electrochemical reduction.

[0285] Embodiment 59. The process for producing a composite material comprising a plurality of particles according to embodiment 58, wherein the reducing agent is a hydride reagent, dihydrogen, lithium aluminum hydride, borohydride, sodium borohydride, diborane, an organometallic reagent, a Grignard reagent, a dialkyl copper lithium reagent, or a combination thereof.

[0286] Embodiment 60. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting the silicon-carbon composite with a solution or suspension of a lithium precursor and incorporating the lithium precursor into the silicon-carbon composite by infiltration of the solution or suspension; and d. reducing the lithium precursor to form a lithium-silicon-carbon composite material; The process includes:

[0287] Embodiment 61. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting the silicon-carbon composite with a solution or suspension of a lithium precursor and incorporating the lithium precursor into the silicon-carbon composite by infiltration of the solution or suspension; and d. reducing the lithium precursor to form a lithium-silicon alloy-carbon composite material; The process includes:

[0288] Embodiment 62. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. heating the porous carbon framework at an elevated temperature in the presence of a silicon-containing gas to impregnate silicon within the pores of the porous carbon framework to provide a silicon-carbon composite material; c. contacting the silicon-carbon composite with a solution or suspension of a lithium precursor and incorporating the lithium precursor into the silicon-carbon composite by infiltration of the solution or suspension; and d. reducing the lithium precursor to produce a lithium-silicon alloy-carbon composite material, wherein the lithium also contains non-silicon alloy domains; The process includes:

[0289] Embodiment 63. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. reducing the lithium precursor to form a lithium-carbon composite; d. heating the lithium-carbon composite at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and e. the lithium in the composite comprises lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof; The process includes:

[0290] Embodiment 64. A process for producing a composite material comprising a plurality of particles, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. heating the carbon framework containing the lithium precursor at an elevated temperature in the presence of a silicon-containing gas to impregnate the silicon within the pores of the porous carbon framework to provide a lithium-silicon-carbon composite material; and d. The lithium in the composite comprises lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof; The process includes:

[0291] Embodiment 65. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 60 to 64, wherein the lithium precursor is lithium carbonate, lithium acetate, lithium amide, lithium bromide, lithium tetrahydride, lithium peroxide, lithium chloride, lithium fluoride, lithium hydride, lithium hydroxide, lithium hydrogen sulfate, lithium dihydrogen phosphate, lithium nitrate, lithium phosphate, lithium nitride, lithium sulfate, lithium sulfide, lithium disulfide, lithium sulfite, lithium aluminum alloy, lithium aluminum copper alloy, lithium tin alloy, lithium silicon alloy, or a combination thereof.

[0292] Embodiment 66. A process for producing a composite material comprising a plurality of particles according to any one of embodiments 60 to 65, wherein the conversion of the lithium-containing precursor to lithium is achieved by chemical or electrochemical reduction.

[0293] Embodiment 67. The process for producing a composite material comprising a plurality of particles according to embodiment 66, wherein the reducing agent is a hydride reagent, dihydrogen, lithium aluminum hydride, borohydride, sodium borohydride, diborane, an organometallic reagent, a Grignard reagent, a dialkyl copper lithium reagent, or a combination thereof.

[0294] Embodiment 68. An anode electrode comprising the lithium-silicon alloy-carbon composite material of any one of embodiments 1 to 31.

[0295] Embodiment 69. An anode electrode comprising the lithium-silicon alloy-carbon composite material of embodiment 68, which also includes a specific carbon material and a binder.

[0296] Embodiment 70. An anode electrode comprising a lithium-silicon alloy-carbon composite material as described in embodiment 69, wherein the carbon material comprises a carbon conductive additive such as graphite, graphene, Super C45, Super P, Ketjen Black carbon, carbon nanotubes, and carbon nanostructures, and combinations thereof.

[0297] Embodiment 71. A method for manufacturing an anode, comprising: a. providing a porous carbon framework comprising micropores, mesopores, or both, wherein said porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. combining the mixture with a binder solution to form an electrode paste; c. applying electrode paste to the conductor to form an electrode; d. Dry the electrodes at a temperature below 180°C.

[0298] Embodiment 72. An electrochemical storage device comprising an electrode according to any one of embodiments 68 to 70.

[0299] Embodiment 73. The electrochemical storage device of embodiment 72, wherein the cathode to anode pairing is less than 1.05 and the first cycle efficiency is greater than 85%.

[0300] From the foregoing, it will be appreciated that, although specific embodiments of the present disclosure have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the disclosure.

[0301] The various embodiments described above may be combined to provide further embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent documents mentioned herein and / or listed in the application data sheet are incorporated herein by reference in their entirety. Aspects of the embodiments may be modified, if necessary, to employ concepts from various patents, applications, and publications to provide further embodiments.

[0302] U.S. Provisional Patent Application No. 63 / 337,526, filed May 2, 2022, from which this application claims priority, is incorporated by reference in its entirety herein.

[0303] These and other changes may be made to the embodiments in light of the above detailed description of the invention. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments, along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by this disclosure.

Claims

1. A particulate material comprising multiple lithium-silicon-carbon composite particles, wherein the composite particles are as follows: (i) Porous carbon framework; (ii) a plurality of nanoscale amorphous elemental silicon domains located within the micropores and / or mesopores of the porous carbon framework; and (iii) Multiple lithium domains, including lithium-silicon alloy domains, non-silicon alloy domains, or combinations thereof, A particulate material containing

2. Porous carbon scaffold, 0.5 cm ３ The lithium-silicon-carbon composite according to claim 1, having a pore volume greater than / g.

3. The lithium-silicon-carbon composite according to claim 1, further comprising a plurality of particles having a Dv50 of 0.1 to 50 microns.

4. Another 30m ２ The lithium-silicon-carbon composite according to claim 1, having a surface area of ​​less than 1g.

5. Another 900m ２ The lithium-silicon-carbon composite according to claim 1, having a capacity of more than / g.

6. An electrode comprising the lithium-silicon-carbon composite described in claim 1.

7. The electrode according to claim 6, wherein at least one binder material is selected from styrene-butadiene rubber carboxymethylcellulose sodium (SBR-Na-CMC), polyvinylidene fluoride (PVDF), polyimide (PI), polyacrylic acid (PAA), and combinations thereof.

8. The electrode according to claim 6, wherein at least one carbon material is selected from graphite, graphene, carbon conductive additives such as Super C45, Super P, Ketjenblack carbon, carbon nanotubes, carbon nanostructures, and combinations thereof.

9. A lithium-silicon battery comprising the lithium-silicon-carbon composite described in claim 1.

10. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. To provide a silicon-carbon composite material by heating the porous carbon framework at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; and c. Heating the silicon-carbon composite material in the presence of a lithium-containing precursor to produce a lithium-silicon-carbon composite material, wherein the lithium includes silicon-alloy domains, non-silicon-alloy domains, or a combination thereof. A process that includes this.

11. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. Heating a carbon framework in the presence of a lithium-containing precursor to produce a lithium-carbon composite material; and c. Heating the lithium-carbon composite material at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework, thereby providing a lithium-silicon alloy-carbon composite material, where the lithium includes silicon-alloy domains, non-silicon-alloy domains, or a combination thereof. Process

12. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. To provide a silicon-carbon composite material by heating the porous carbon framework at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; and c. Melting a lithium precursor in the presence of the silicon-carbon composite material to produce a lithium-silicon-carbon composite material, wherein the lithium includes silicon-alloy domains, non-silicon-alloy domains, or a combination thereof. A process that includes this.

13. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. Heating the porous carbon framework at a temperature above the melting point of the lithium precursor in the presence of a silicon-containing gas and a lithium precursor, thereby impregnating both silicon and lithium into one or more pores of the porous carbon framework; and c. The lithium in the composite includes lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof. A process that includes this.

14. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. Melting a lithium precursor in the presence of a carbon framework material to produce a lithium-silicon composite material; c. To provide a lithium-silicon-carbon composite material by heating a lithium-carbon composite at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; and d. The lithium in the composite includes lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof. A process that includes this.

15. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. To provide a silicon-carbon composite material by heating the porous carbon framework at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; c. Contacting a silicon-carbon composite with a solution or suspension of a lithium precursor, thereby incorporating the lithium precursor into the silicon-carbon composite by the infiltration of the solution or suspension; and d. Reducing the lithium precursor to produce a lithium-silicon-carbon composite material, wherein the lithium in the composite includes lithium-silicon alloy domains, non-silicon alloy domains, or combinations thereof. A process that includes this.

16. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. Contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. Reducing the lithium precursor to produce a lithium-carbon composite; d. To provide a lithium-silicon-carbon composite material by heating the lithium-carbon composite at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; and e. The lithium in the composite includes lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof. A process that includes this.

17. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon framework comprising micropores, mesopores, or both, wherein the porous carbon framework comprises particles having a Dv50 of 0.1 to 50 microns; b. Contacting the porous carbon framework with a solution or suspension of a lithium precursor to incorporate the lithium precursor into one or more pores of the porous carbon framework; c. To provide a lithium-silicon-carbon composite material by heating the carbon framework containing the lithium precursor at a high temperature in the presence of a silicon-containing gas to impregnate silicon into the pores of the porous carbon framework; and d. The lithium in the composite includes lithium-silicon alloy domains, non-silicon alloy domains, or a combination thereof. A process that includes this.

18. A process for manufacturing a composite material containing multiple particles, the following: a. To provide a porous carbon scaffold having micropores and mesopores; b. Introducing a compound containing Si and Fe, Al, Ni, W, or Ti into the micropores and mesopores of the porous carbon scaffold by chemical vapor impregnation to form a metal-carbon composite; c. A surface coating layer containing aluminum oxide or zirconium oxide is applied to the surface region of the metal-carbon composite, thereby forming a surface-coated silicon-carbon composite on the surface region of the silicon-carbon composite. A process that includes this.

19. The lithium-silicon alloy-carbon composite according to claim 1, further comprising at least partially applied surface coating layers that form a surface coating on a surface region of a composite comprising at least one or more elements of C, Si, Li, Al, Ti, Zr, Nb, and W.

20. The lithium-silicon alloy-carbon composite according to claim 18, further comprising at least a partially applied surface coating layer that forms a surface coating on a surface area of ​​a composite having an oxide containing aluminum, zirconium, titanium, or a combination thereof.

21. The process for producing the lithium-silicon-carbon composite material according to claim 18, wherein the surface coating is based on a gas vapor phase growth method.

22. The aforementioned surface coating is as follows: a. Treating a composite material with a metal alkoxide, metal amide, or alkyl metal compound to form a treated compound. b. The treated compound is treated with water, oxygen, or ozone to form a surface coating layer. A process for producing the lithium-silicon-carbon composite material according to claim 18, based on the above.

23. A process for producing a lithium-silicon alloy-carbon composite material according to claim 18, wherein the coating of the surface coating region is carried out at a temperature in the range of 15°C to 450°C.

24. Anode electrode containing lithium-silicon alloy-carbon composite particles including the following: a. 0.5 cm ３ A porous carbon framework containing micropores and mesopores having a total pore volume of 1 / g or more; b. Silicon content of 30% to 70%; c. A plurality of nanoscale amorphous elemental silicon domains located within the micropores and / or mesopores of the porous carbon framework; and d. Multiple lithium domains, including a lithium-silicon alloy.

25. The anode electrode according to claim 24, further comprising at least partially applied surface coating layers that form a surface coating region on a surface region of a silicon-carbon composite containing at least one or more elements selected from Li, B, Al, Si, P, Ti, Zr, Nb, and W.

26. The anode electrode according to claim 25, wherein the surface coating layer has a thickness in the range of 0.1 nm to 1 μm.

27. The anode electrode according to claim 24, wherein the surface coating layer is composed of a metal oxide derived from at least one or more elements selected from B, Al, Si, Zr, and Li.

28. The anode electrode according to claim 24, wherein the surface coating region covers at least 50% or more of the surface region of the silicon-carbon composite.

29. The anode electrode according to claim 24, wherein the composite material includes a further coating on a surface coating layer, so that the surface coating layer and the further coating form a surface coating region.

30. The anode electrode according to claim 29, wherein the further coating is a carbon coating.

31. The following steps: a. A mixture is prepared by mixing a lithium-silicon alloy-carbon composite with at least one carbon; b. The mixture and the binder solution are combined to form an electrode paste; c. Apply the electrode paste to the conductor to form at least one electrode; d. Dry the at least one electrode at a temperature of less than 180°C. A process for manufacturing the anode electrode according to claim 24, including the process described in claim 24.

32. Electrochemical storage devices, particularly those formed as lithium-silicon batteries, including the following: a. At least one anode electrode according to claim 24; b. At least one electrode containing a transition metal oxide, formed as a cathode; c. A separator placed between the cathode and the anode; and d. Electrolytes containing lithium ions.

Images