Highly efficient manufacturing of silicon-carbon composite materials containing very low Z

Abstract

Silicon-carbon composite materials and related methods are disclosed that solve the problem of providing amorphous nanosized silicon incorporated within porous carbon. Compared to other inferior materials and methods described in the prior art, the materials and methods disclosed herein find superior utility in a variety of applications, for example, for use in energy storage devices such as lithium-ion batteries.

Description

[Technical Field]

[0001] Embodiments of the present invention generally relate to a method for producing a silicon-carbon composite material having properties that solve the problem of providing amorphous nano-sized silicon incorporated within porous carbon. The silicon-carbon composite is produced by impregnating amorphous nano-sized silicon into the pores of a porous scaffold by chemical vapor phase infiltration. Suitable porous scaffolds are not particularly limited, but include, for example, porous carbon scaffolds and carbon having pore volumes including, for example, micropores (less than 2 nm), mesopores (2 to 50 nm), and / or macropores (greater than 50 nm). Suitable precursors for carbon scaffolds are not particularly limited, but include, for example, sugars and polyols, organic acids, phenolic compounds, crosslinking agents, and amine compounds. Suitable composite materials are not particularly limited, but include, for example, silicon materials. The silicon precursor is not particularly limited, but includes, for example, silicon-containing gases, such as silanes, higher silanes (di-, tri-, and / or tetrasilanes, etc.), and / or chlorosilanes (mono-, di-, tri-, and tetrachlorosilanes, etc.), and mixtures thereof. Chemical vapor infiltration (CVI) of silicon into the pores of the porous scaffold material is achieved by exposing the porous scaffold to a silicon-containing gas (e.g., silane) at high temperatures. The porous carbon scaffold may be porous carbon in the form of particulate matter.

[0002] A significant achievement in this regard is the attainment of a desired form of silicon, namely amorphous nanoscale silicon. Furthermore, another significant achievement is the attainment of silicon impregnation into the pores of porous carbon. Furthermore, another significant achievement is the attainment of high utilization of silicon-containing gas, i.e., the attainment of introducing most silicon into a CVI reactor. The CVI reactor converts the silicon impregnated into the pores of porous carbon into amorphous nanoscale silicon. Therefore, such a manufacturing method and the manufactured material (e.g., silicon-carbon composite material) have utility as an anode material for energy storage devices (e.g., lithium-ion batteries).

[0003] Description of related fields CVI is a process in which a gaseous substrate is reacted within a porous scaffold material. This approach can be used to produce composite materials (e.g., silicon-carbon composites) by decomposing a silicon-containing gas at high temperatures within a porous carbon scaffold. This approach can be used in the manufacture of various composite materials, and is of particular interest in silicon-carbon (Si-C) composite materials. Such Si-C composite materials have utility, for example, as energy storage materials (e.g., anode material in lithium-ion batteries (LIBs)). LIBs have the potential to replace many applications currently in use. For example, today's automotive lead-acid batteries are unsuitable for next-generation all-electric and hybrid electric vehicles because they form irreversible and stable sulfates during discharge. Lithium-ion batteries can replace currently used lead-based systems due to their capacity and other considerations.

[0004] To achieve this objective, there continues to be strong interest in the development of new LIB anode materials, particularly silicon, which has 10 times the weight capacity compared to conventional graphite. However, silicon exhibits large volume changes during cycling, resulting in electrode degradation and destabilization of the solid electrolyte interface (SEI). The most common improvement approach is to reduce the particle size of silicon, either as individual particles or within a matrix (e.g., D V,50 <150nm, for example D V,50 <100nm, for example D V,50 <50nm, for example D V,50 <20nm, for example, D V,50 <10nm, for example, D V,50 <5nm, for example D V,50 The size is <2nm). Until now, nanoscale silicon manufacturing technologies have involved high-temperature reduction of silicon dioxide, broad-spectrum particle reduction, multi-step toxic etching, and / or other costly processes. Similarly, common matrix approaches involve expensive materials such as graphene or nanographite and / or require complex processes and coatings.

[0005] Scientific literature has shown that non-graphitizable (hard) carbon is useful as a LIB anode material (Liu Y, Xue, JS, Zheng T, Dahn, JR. Carbon 1996, 34:193-200; Wu, YP, Fang, SB, Jiang, YY. 1998, 75:201-206; Buiel E, Dahn JR. Electrochim Acta 1999 45:121-130). The basis for this performance improvement lies in the disordered nature of the graphene layer, that is, the intercalation of Li ions on both sides of the graphene, which theoretically doubles the stoichiometric content of Li ions compared to crystalline graphite. Furthermore, in contrast to graphite, where lithiation proceeds only parallel to the stacked graphene plane, the disordered structure created by isotropically intercalating Li ions increases the material's rated capacity. Despite these desirable electrochemical properties, amorphous carbon has not seen widespread adoption in commercial lithium-ion batteries, mainly due to its low FCE and low bulk density (<1 g / cc). Instead, amorphous carbon is more commonly used as a low-mass additive and coating for other active material components in batteries to improve conductivity and suppress surface reactions.

[0006] In recent years, amorphous carbon has attracted considerable attention as a material for LIB batteries and as a coating for silicon anode materials. Such silicon-carbon core-shell structures not only improve conductivity but also have the ability to mitigate the expansion that occurs when silicon is lithiated, thereby stabilizing cycle stability and minimizing problems related to particle pulverization, separation, and SEI integrity (Jung, Y, Lee K, Oh, S. Electrochim Acta 2007 52:7061-7067; Zuo P, Yin G, Ma Y.. Electrochim Acta 2007 52:4878-4883; Ng SH, Wang J, Wexler D, Chew SY, Liu HK. J Phys Chem C 2007 111:11131-11138). Problems associated with this method include a lack of suitable silicon starting materials for the coating process, and an intrinsic lack of engineering voids within the carbon-coated silicon core-shell composite particles to accommodate the expansion of silicon during lithiation. This inevitably leads to a lack of cycle stability due to the breakdown of the core-shell structure and SEI layer. (Beattie SD, Larcher D, Morcrette M, Simon B, Tarascon, JM. J Electrochem Soc 2008 155:A158-A163). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application No. 7723262 [Patent Document 2] U.S. Patent Application No. 8293818 [Patent Document 3] U.S. Patent Application No. 8404384 [Patent Document 4] U.S. Patent Application No. 8654507 [Patent Document 5] U.S. Patent Application No. 8916296 [Patent Document 6] U.S. Patent Application No. 9269502 [Patent Document 7] U.S. Patent Application No. 10590277 [Patent Document 8] U.S. Patent Application Publication No. 2016 / 745197 [Patent Document 9] U.S. Patent Application Publication No. 2016 / 996694 [Patent Document 10] U.S. Provisional Patent Application No. 63 / 075566 [Patent Document 11] U.S. Provisional Patent Application No. 63 / 078806 [Non-patent literature]

[0008] [Non-Patent Document 1] Liu Y, Xue, JS, Zheng T, Dahn, JR. Carbon 1996, 34:193-200; Wu, YP, Fang, SB, Jiang, YY. 1998, 75:201-206 [Non-Patent Document 2] Buiel E, Dahn JR. Electrochim Acta 1999 45:121-130 [Non-Patent Document 3] Jung, Y, Lee K, Oh, S. Electrochim Acta 2007 52:7061-706 [Non-Patent Document 4] Zuo P, Yin G, Ma Y.. Electrochim Acta 2007 52:4878-4883 [Non-Patent Document 5] Ng SH, Wang J, Wexler D, Chew SY, Liu HK. J Phys Chem C 2007 111:11131-11138 [Non-Patent Document 6] Beattie SD, Larcher D, Morcrette M, Simon B, Tarascon, JM. J Electrochem Soc 2008 155:A158-A163 [Non-Patent Document 7] The Chemistry and Applications of Metal-Organic Frameworks, Hiroyasu Furukawa et al. Science 341, (2013); DOI: 10.1126 / science.1230444 [Overview of the project] [Problems that the invention aims to solve]

[0009] An alternative structure to the core-shell structure is one in which amorphous nano-sized silicon is uniformly distributed within the voids of a porous carbon scaffold. Porous carbon has desirable properties: (i) The porosity of carbon provides void volume, which adapts to the expansion of silicon during lithiation, thus reducing the net expansion of composite particles at the electrode level; (ii) The disordered graphene network enhances electrical conductivity to silicon, thus enabling faster charge / discharge speeds; and, (iii) The nanoporous structure functions as a template for the synthesis of silicon, thus defining its size, distribution, and morphology. Give. [Means for solving the problem]

[0010] In this regard, the desired inverse hierarchical structure can be achieved by using CVI, where the silicon-containing gas can completely penetrate the nanoporous carbon and decompose into nanoscale silicon. The CVI approach offers several advantages in terms of silicon structure. One advantage is that the nanoporous carbon provides nucleation sites for silicon growth while defining the maximum particle shape and particle size. Limiting silicon growth within the nanoporous structure reduces susceptibility to cracking or pulverization and reduces contact caused by expansion. Furthermore, this structure facilitates the retention of nanoscale silicon in the amorphous phase. This property provides opportunities for high charge / discharge rates, especially in combination with silicon proximity within conductive carbon scaffolds. This system provides a high-speed compatible diffusion pathway for solid-state lithium, which directly supplies lithium ions to the nanoscale silicon interface. Another advantage of silicon provided by CVI within carbon scaffolds is the avoidance of undesirable crystallized Li 15 This inhibits the formation of the Si4 layer. Another further advantage is that the CVI process creates voids within the particles.

[0011] Thermogravimetric analysis (TGA) may be used to quantify the proportion of silicon in the introduced silicon-carbon composite. For this purpose, the silicon-composite is heated from 25°C to 1100°C. Although not bound by theory, at this temperature, all carbon burns and all silicon oxidizes to SiO2. Thus, the proportion (%) of silicon in the silicon-carbon composite is given by the following formula: %Si=100×[[M1100×(28 / (28+(16×2)))] / M°] [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M° is the minimum mass of the silicon-carbon composite between 30°C and 200°C. These masses are determined by thermogravimetric analysis.] It is calculated from.

[0012] Thermogravimetric analysis (TGA) may be used to measure the relative amount of silicon impregnated into the pores of porous carbon. TGA can be used to assess the proportion of silicon present in the pores of porous carbon relative to the total silicon present, i.e., the sum of silicon in the pores and on the particle surface. When a silicon-carbon composite is heated in air, the sample shows a mass increase between 300°C and 500°C, which reflects the initiation of silicon oxidation to SiO2. Subsequently, the sample shows a mass decrease as the carbon burns. The sample then shows a mass increase reflecting the resumption of the conversion of silicon to SiO2, which increases towards an asymptotic value of 1100°C until the oxidation of silicon is complete. For the purposes of this analysis, the minimum mass recorded for a sample heated from 800°C to 1100°C is estimated to represent the point at which the combustion of carbon is complete. Any further mass increase beyond this point corresponds to the oxidation of silicon to SiO2, and the total mass at the point of oxidation completion is SiO2. Thus, the ratio of unoxidized silicon after carbon combustion to the total weight of silicon is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, M1100 is the mass of the sample after oxidation is complete at 1100°C, and M is the minimum mass recorded for a sample heated from 800°C to 1100°C.] It can be determined by this method.

[0013] While not theoretically bound, the temperature at which silicon oxidizes under TGA conditions is related to the length scale of the oxide coating on the silicon due to the diffusion of oxygen atoms through the oxide layer. Thus, silicon present within carbon pores will oxidize at a lower temperature than silicon deposits on the particle surface because the coating on the particle surface is necessarily thinner. In this way, Z calculations are used to quantitatively assess the fraction of silicon that has not penetrated into the pores of a porous carbon scaffold.

[0014] Simple summary This paper discloses silicon-carbon composite materials and related processes that address the challenge of providing amorphous nano-sized silicon impregnated within porous carbon. Compared to other inferior materials and processes described in prior art, the materials and processes disclosed herein have proven useful in a variety of applications, including energy storage devices such as lithium-ion batteries. [Brief explanation of the drawing]

[0015] [Figure 1] The relationship between Z and mean Coulomb efficiency in various silicon-carbon composite materials. [Figure 2] Differential capacitance vs. voltage plot for the second cycle in silicon-carbon composite 3 using half-cells. [Figure 3] Differential capacitance vs. voltage plots for cycles 2-5 in silicon-carbon composite 3 using half-cells. [Figure 4] dQ / dV vs V plots for various silicon-carbon composite materials. [Figure 5] An example of calculating φ in silicon-carbon composite 3. [Figure 6] Z vs φ plots for various silicon-carbon composite materials. [Figure 7] YCVI vs XSi plots in various silicon-carbon composite materials. [Figure 8] Silane utilization rate (%) as a function of runtime during the preparation of sample 21, as determined by Fourier transform infrared spectrophotometer (FTIR) analysis.

[0016] Detailed explanation The following description provides specific details to give a full understanding of the various embodiments. However, those skilled in the art will understand that the invention can be implemented without these details. In other examples, known structures are not shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. Unless otherwise noted, in the following specification and claims, the term “comprise,” and its derivatives, e.g., “comprises,” and “comprising,” etc., are to be interpreted in an open and comprehensive sense, i.e., “including, but not limited to.” Furthermore, the headings described herein are for convenience only and do not constitute an interpretation of the scope or meaning of the claimed invention.

[0017] Throughout this specification, any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in relation to that embodiment is included in at least one embodiment. Therefore, the phrases “in one embodiment” or “in an embodiment” appearing in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic can be combined in any suitable way in one or more embodiments. Also, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include multiple references unless otherwise noted. Also, unless otherwise noted, the term “or” is generally used to include “and / or.” [Modes for carrying out the invention]

[0018] A. Porous scaffold material For the purposes of the embodiments of the present invention, a silicon-impregnated porous scaffold may be used. In this embodiment, the porous scaffold can be made of a variety of materials. In some embodiments, the porous scaffold mainly contains carbon, such as hard carbon. Other allotropes of carbon (e.g., graphite, amorphous carbon, diamond, C60, carbon nanotubes (e.g., single-layer and / or multi-layer), graphene, and / or carbon fiber) are also envisioned in other embodiments. The introduction of pores into carbon materials can be achieved by various methods. For example, pores in carbon materials can be achieved by the preparation (modulation) of polymer precursors and / or processing conditions when producing the porous carbon material, which will be described in detail in the following sections.

[0019] In other embodiments, the porous scaffold comprises a polymer material. For this purpose, in various embodiments, a wide range of practical polymers (not particularly limited, but including, inorganic polymers, organic polymers, and addition polymers) are envisioned. Inorganic polymers in the present invention include, not particularly limited, silicon-silicon homochain polymers, such as polysilanes, silicon carbides, polygermanes, and polystannanes. Further examples of inorganic polymers include, not particularly limited, heterochain polymers, such as polyborazylenes, and polysiloxanes such as polydimethylsiloxane (PDMS), polymethylhydrosiloxane (PMHS), and polydiphenylsiloxane, as well as polysilazanes such as perhydridopolysilazane (PHPS), polyphosphazenes, and poly(dichlorophosphazenes), and polyphosphates, polythiazyls, and polysulfides. Examples of organic polymers are not particularly limited, but include, for example, 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, polylactic acid, polyglycolides, and combinations thereof, phenolic resins, polyamides, polyaramids, polyethylene terephthalate, polychloroprene, polyacrylonitrile, polyaniline, polyimide, poly(3,4-ethylenedioxythiophene)polystyrene sulfonic acid (PDOT:PSS), and other organic polymers known in the art. The organic polymer may be synthetic or natural. In some embodiments, the polymer is a polysaccharide, such as starch, cellulose, cellobiose, amylose, amylopectin, gum arabic, lignin, etc.In some embodiments, the polysaccharide is derived from the caramelization of monosaccharides or oligosaccharides (e.g., fructose, glucose, sucrose, maltose, and raffinose).

[0020] In certain embodiments, the porous scaffold polymer material includes a coordination polymer. The coordination polymer in this embodiment is not particularly limited, but includes, for example, metal-organic frameworks (MOFs). The manufacturing techniques for MOFs, as well as exemplary MOF species, are known in the art and are described in the following document (The Chemistry and Applications of Metal-Organic Frameworks, Hiroyasu Furukawa et al. Science 341, (2013); DOI: 10.1126 / science.1230444). The MOFs in this invention are not particularly limited, but include, for example, Basolite® materials and zeolitic imidazolate frameworks (ZIFs).

[0021] With the vast number of polymers that are assumed to have the potential to provide porous substrates, various processing approaches are envisioned in various embodiments for achieving the pores described above. In this embodiment, there are countless common methods for imparting pores to various materials, including methods known in the art (e.g., emulsification, micelle formation, gasification, solvent removal after dissolution (e.g., freeze-drying), axial compaction and sintering, gravity sintering, powder rolling and sintering, metal spraying, metal coating and sintering, metal injection molding and sintering, etc.). Other approaches for producing porous polymer materials are also envisioned, such as the production of porous gels, including freeze-dried gels and aerogels.

[0022] In certain embodiments, the porous scaffold material includes a porous ceramic material. In certain embodiments, the porous scaffold material includes a porous ceramic foam. In this embodiment, there are various, but are not limited, common methods for imparting pores to a ceramic material, but as is known in the art, one example is the fabrication of a porous structure. In this embodiment, suitable common methods and materials for incorporating porous ceramics are, but are not limited, common examples including 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, and viscosity-bonded silicon carbide.

[0023] In certain embodiments, the porous scaffold comprises porous silica or other oxygen-containing silicon material. The preparation of sol gels and silicon gels comprising other porous silica materials is known in the art.

[0024] In certain embodiments, the porous material includes a porous metal. Suitable metals in this regard are not particularly limited, but include, for example, porous aluminum, porous steel, porous nickel, porous Inconcel, porous Hasteloy, porous titanium, porous copper, porous brass, porous gold, porous silver, porous germanium, and other metals known in the art that can form porous structures. In some embodiments, the porous scaffold material includes a porous metal foam. The types of metals and methods of production related to the above are known in the art. Such methods are not particularly limited, but include, for example, casting (including foaming, infiltration, and lost-foam casting), agglomeration (chemical and physical), gas eutectic formation, powder metallurgy techniques (powder sintering, compression in the presence of a foaming agent, and fiber metallurgy techniques, etc.).

[0025] B. Porous carbon scaffold 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 Application No. 7723262, U.S. Patent Application No. 8293818, U.S. Patent Application No. 8404384, U.S. Patent Application No. 8654507, U.S. Patent Application No. 8916296, U.S. Patent Application No. 9269502, U.S. Patent Application No. 10590277, and U.S. Patent Publication No. 2016 / 745197, all of which are incorporated herein by reference for all purposes.

[0026] Accordingly, in one embodiment, the present disclosure provides a method for preparing any of the carbon materials or polymer gels described above. The carbon material may be synthesized by the thermal decomposition of any single precursor, for example, a sugar material (sucrose, fructose, glucose, dextrin, maltodextrin, starch, amylopectin, amylose, lignin, gum arabic, and other sugars known in the art, and combinations thereof). Alternatively, the carbon material may be synthesized by the thermal decomposition of a composite resin. The composite resin is formed, for example, by a sol-gel method using a polymer precursor together with a crosslinking agent in a suitable solvent. Examples of the polymer precursor include phenol, resorcinol, bisphenol A, urea, melamine, and other suitable compounds known in the art, and combinations thereof. Examples of the suitable solvent include water, ethanol, methanol, and other solvents known in the art, and combinations thereof. Examples of the crosslinking agents include formaldehyde, hexamethylenetetramine, furfural, other crosslinking agents known in the art, and combinations thereof. The resin may be acidic or basic, and may contain a catalyst. The catalyst may be volatile or non-volatile. The thermal decomposition temperature and reaction time may vary, as known in the art.

[0027] In some embodiments, the method of the present invention comprises the preparation of a polymer gel by a sol-gel process, a condensation process or a crosslinking process (where the process includes a monomer precursor and a crosslinking agent, two polymers and a crosslinking agent in a system, or a single polymer and a crosslinking agent), followed by the thermal decomposition of the polymer gel. The polymer gel may be dried (e.g., freeze-dried) before thermal decomposition; however, drying is not necessarily required.

[0028] When a polymerization reaction produces a resin / polymer with the required carbon backbone, the carbon properties of the target can derive from the chemical properties of various polymers. Various polymer species include novolacs, resols, acrylates, styrenes, urethanes (ureathanes), rubbers (neoprene, styrene-butadiene, etc.), nylon, and others. The preparation of any of the above polymer resins can occur through various processes related to polymerization and crosslinking (e.g., sol-gel, emulsion / suspension, solid, liquid, molten, etc.).

[0029] In some embodiments, an electrochemical modifier is introduced into the material as a polymer. For example, an organic or carbon-containing polymer (e.g., RF) copolymerizes with the polymer and contains an electrochemical modifier. In one embodiment, the electrochemical modifier-containing polymer contains silicon. In one embodiment, the polymer is tetraethylorthosilane (TEOS). In one embodiment, a TEOS solution is added to the RF solution before or during polymerization. In other embodiments, the polymer is a polysilane having side groups. In some examples, these side groups are methyl groups, and in other examples, these side groups are phenyl groups. In some examples, the side chains contain group 14 elements (silicon, germanium, tin, or lead). In other examples, the side chains contain group 13 elements (boron, aluminum, boron, gallium, or indium). In other examples, the side chains contain group 15 elements (nitrogen, phosphorus, or arsenic). In other examples, the side chains contain group 16 elements (oxygen, sulfur, or selenium).

[0030] In other embodiments, the electrochemical modifier includes silole. In some examples, it is phenol-silole or silafluorene. In other examples, it is poly-silole or poly-silafluorene. In some examples, silicon is replaced by germanium (germole or germafluorene), tin (stannole or stannafluorene), nitrogen (carbazole), or phosphorus (phosphole or phosphafluorene). In all examples, the heteroatom-containing material may be a small molecule, oligomer, or polymer. The phosphorus atom may or may not be bonded to oxygen.

[0031] In some embodiments, the reactant contains phosphorus. In other specific embodiments, phosphorus is in the form of phosphoric acid. In other specific embodiments, phosphorus may be in the form of a salt, the salt's anion of which contains one or more phosphoric acid, phosphorous acid, phosphide, hydrogen phosphate, dihydrogen phosphate, hexafluorophosphate, hypophosphorous acid, polyphosphate, or pyrophosphate ions, or a combination thereof. In other embodiments, phosphorus may be in the form of a salt, the salt's cation of which contains one or more phosphonium ions. Non-phosphates containing any of the anion or cation pairs of the above embodiments can be selected from those known and described in the art. Typical cations that form pairs with the phosphoric acid-containing anion in this embodiment are not particularly limited, but include, for example, ammonium, tetraethylammonium, and tetramethylammonium ions. Typical anions that form pairs with the phosphoric acid-containing cation in this embodiment are not particularly limited, but include, for example, carbonic acid, dicarbonate, and acetate ions.

[0032] In some embodiments, the catalyst includes a volatile base catalyst. For example, in one embodiment, the volatile base catalyst includes ammonium carbonate, ammonium dicarbonate, ammonium acetate, ammonium hydroxide, or a combination thereof. In yet another embodiment, the volatile base catalyst is ammonium carbonate. In other embodiments, the volatile base catalyst is ammonium acetate.

[0033] In further embodiments, the method of the present invention involves mixing acids. In certain embodiments, the acid is solid at room temperature and room pressure. In some embodiments, the acid is liquid at room temperature and room pressure. In some embodiments, the acid is liquid at room temperature and room pressure and does not dissolve one or more other polymer precursors.

[0034] The acid may be selected from many acids suitable for the polymerization process. For example, in some embodiments, the acid is acetic acid, and in other embodiments, the acid is oxalic acid. In further embodiments, the acid is mixed with a first or second solvent such that the ratio of acid to solvent is 99:1, 90:10, 75:25, 50:50, 25:75, 20:80, 10:90, or 1:90. In other embodiments, the acid is acetic acid and the first or second solvent is water. In other embodiments, the solution is acidified by adding a solid acid.

[0035] The properties of the final product can be altered by changing the total acid content in the mixture. In some embodiments, the acid is present in the mixture at a weight ratio of about 1% to about 50%. In other embodiments, the acid is present at a weight ratio of about 5% to about 25%. In other embodiments, the acid is present at a weight ratio of about 10% to about 20% (e.g., about 10%, about 15%, about 20%).

[0036] In certain embodiments, polymer precursor components are blended together and then held at a temperature and time sufficient for polymerization to complete. One or more polymer precursor components may have a particle size of less than 20 mm (e.g., less than 10 mm, less than 7 mm, less than 5 mm, less than 2 mm, less than 1 mm, less than 100 microns, less than 10 microns). In some embodiments, the particle size of one or more polymer precursor components decreases during the blending process.

[0037] Blending one or more polymer precursor components in a solvent-free environment can be achieved by methods described in the art (e.g., ball milling, jet milling, Fritsch milling, planetary mixing, and other mixing methods relating to mixing or blending solid particles while controlling process conditions (e.g., temperature)). The mixing or blending process can be achieved before, during, and / or after incubation at the reaction temperature (or a combination thereof).

[0038] The reaction parameters include aging the blend mixture at room temperature for a sufficient time for one or more polymer precursors to react with each other and form a polymer. In this regard, a suitable aging temperature is in the range of approximately room temperature to or near the melting point of one or more polymer precursors. In some embodiments, a suitable aging temperature is in the range of approximately room temperature to or near the glass transition temperature of one or more polymer precursors. For example, in some embodiments, the solvent-free mixture is aged at about 20°C to about 600°C (e.g., about 20°C to about 500°C, e.g., about 20°C to about 400°C, e.g., about 20°C to about 300°C, e.g., about 20°C to about 200°C). In certain embodiments, the solvent-free mixture is aged at about 50°C to about 250°C.

[0039] The reaction time is generally sufficient for the polymer precursor to react and produce a polymer. For example, the mixture may be aged for 1 to 48 hours at any given time, or longer or shorter depending on the desired result. Typical embodiments include aging in the range of about 2 to about 48 hours, for example, about 12 hours in some embodiments and about 4 to 8 hours (e.g., 6 hours) in other embodiments.

[0040] In certain embodiments, an electrochemical modifier is introduced during the polymerization process described above. For example, in some embodiments, the electrochemical modifier, which may be in the form of metal particles, metal paste, metal salt, metal oxide, or molten metal, may be dissolved or suspended in the mixture that produces the gel resin.

[0041] Typical electrochemical modifiers used to create composite materials may fall into one or more chemical classifications. In some embodiments, the electrochemical modifier is a lithium salt, and is not particularly limited, but examples include lithium fluoride, lithium chloride, lithium carbonate, lithium hydroxide, lithium benzoate, lithium bromide, lithium formate, lithium hexafluorophosphate, lithium iodate, lithium iodide, lithium perchlorate, lithium phosphate, lithium sulfate, lithium tetraborate, lithium tetrafluoroborate, and combinations thereof.

[0042] In certain embodiments, the electrochemical modifier includes metals, and typical species are not particularly limited but include, for example, aluminum isoproproxide, manganese acetate, nickel acetate, iron acetate, tin chloride, silicon chloride, and combinations thereof. In certain embodiments, the electrochemical modifier is a phosphoric acid compound, and is not particularly limited but includes, for example, phytic acid, phosphoric acid, ammonium dihydrogen phosphate, and combinations thereof. In certain embodiments, the electrochemical modifier includes silicon, and typical species are not particularly limited but include, for example, silicon powder, silicon nanotubes, polycrystalline silicon, nanocrystalline silicon, amorphous silicon, porous silicon, nano-sized silicon, nano-featured silicon, nano-sized and nano-featured silicon, silicine, and black silicon, and combinations thereof.

[0043] Electrochemical modifiers can be bonded to various polymer systems by either physical mixing or chemical reaction with potential (or secondary) polymer functional groups. Examples of potential polymer functional groups are not limited to but include epoxides, unsaturated (double or triple bonds), acids, alcohols, and bases. Crosslinking with potential functional groups can occur through reactions with heteroatoms (e.g., vulcanization with sulfur, and acid / base / ring-opening reactions with phosphoric acid), reactions with organic acids or bases (as described above), coordination to transition metals (e.g., titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, silver, gold, etc., but not limited to these), and ring-opening or ring-closing reactions (of rotaxanes, spiro compounds, etc.).

[0044] Furthermore, electrochemical modifiers can be added to polymer systems by physical blending. Physical blending is not particularly limited, but may include, for example, melt blending of polymers and / or copolymers, incorporation of discrete particles, vapor phase chemical growth of electrochemical modifiers, and coprecipitation of electrochemical modifiers and the main polymer material.

[0045] In some examples, the electrochemical modifier may be added via a solid, solution, or suspension of the metal salt. The metal salt solid, solution, or suspension may contain an acid and / or alcohol to enhance the solubility of the metal salt. In other further variations, the polymer gel (either before or after any drying step) comes into contact with a paste containing the electrochemical modifier. In yet another variation, the polymer gel (either before or after any drying step) comes into contact with a metal or metal oxide containing the desired electrochemical modifier.

[0046] In addition to the electrochemical modifiers exemplified above, the composite material may contain one or more additional forms (i.e., allotropes) of carbon. In this regard, the inclusion of various allotropes of carbon (graphite, amorphous carbon, conductive carbon, carbon black, diamond, C60, carbon nanotubes (e.g., single-layer and / or multi-layer), graphene, and / or carbon fiber, etc.) in the composite material has been found to be effective in optimizing the electrochemical properties of the composite material. Various allotropes of carbon can be introduced into the carbon material at any stage of the preparation process described herein (e.g., during the dissolution phase, gelation phase, curing phase, pyrolysis phase, milling phase, or after milling). In some embodiments, the second carbon foam is introduced into the composite material by adding the second carbon foam during or before polymerization of the polymer gel, as described in more detail herein. The polymerized polymer gel containing the second carbon foam is processed according to the general method described herein to obtain a carbon material containing the second allotrope of carbon.

[0047] In preferred embodiments, the carbon is produced from a precursor that requires little or no solvent for processing. The structure of the polymer precursor suitable for use in a reaction mixture with little or essentially no solvent is not particularly limited. However, the polymer precursor may react with other polymer precursors or a second polymer precursor to produce a polymer. The polymer precursors include amine-containing compounds, alcohol-containing compounds, and carbonyl-containing compounds, and in some embodiments, for example, the polymer precursor is selected from alcohols, phenols, polyalcohols, sugars, alkylamines, aromatic amines, aldehydes, ketones, carboxylic acids, esters, ureas, acid halides, and isocyanates.

[0048] In one embodiment using a reaction mixture with little solvent or essentially solvent-free solvent, the method comprises the use of first and second polymer precursors, and in some embodiments, one of the first or second polymer precursors is a carbonyl-containing compound and the other is an alcohol-containing compound. In some embodiments, the first polymer precursor is a phenol compound and the second polymer precursor is an aldehyde compound (e.g., formaldehyde). In one embodiment, the phenol compound of the above method is phenol, resorcinol, catechol, hydroquinone, phloroglucinol, or a combination thereof; and the aldehyde compound is formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, cinnamaldehyde, or a combination thereof. In a further embodiment, the phenol compound is resorcinol, phenol, or a combination thereof, and the aldehyde compound is formaldehyde. In a further embodiment, the phenol compound is resorcinol and the aldehyde compound is formaldehyde. In some embodiments, the polymer precursors are alcohols and carbonyl compounds (e.g., resorcinol and aldehyde), and they are present in a ratio of approximately 0.5:1.0.

[0049] The polymer precursor materials suitable for reaction mixtures with little solvent or essentially no solvent, as described herein, include (a) alcohols, phenolic compounds, and other mono- or polyhydroxy compounds, and (b) aldehydes, ketones, and combinations thereof. Typical alcohols in this embodiment include linear and branched saturated and unsaturated alcohols. Suitable phenolic compounds include polyhydroxybenzenes (such as dihydroxy or trihydroxybenzene). Typical polyhydroxybenzenes include resorcinol (i.e., 1,3-dihydroxybenzene), catechol, hydroquinone, and phloroglucinol. Other suitable compounds in this regard are bisphenols (e.g., bisphenol A). Mixtures of two or more polyhydroxybenzenes can also be used. Phenols (monohydroxybenzene) can also be used. Typical polyhydroxy compounds include sugars (e.g., glucose, sucrose, fructose, chitin, and other polyols such as mannitol). Aldehydes in this embodiment include: Straight-chain saturated aldehydes, such as methanal (formaldehyde), ethanal (acetaldehyde), propanal (propionaldehyde), and butanal (butyraldehyde); Linear unsaturated aldehydes, such as ethenone and other ketenes, as well as 2-propenal (acrylaldehyde), 2-butenal (crotonaldehyde), and 3-butenal, etc. Branched chain saturated and unsaturated aldehydes; and Aromatic aldehydes, such as benzaldehyde, salicylaldehyde, and hydrocinnamaldehyde. Includes the following ketones: Linear saturated ketones, such as propanone and 2-butanone; Linear unsaturated ketones, such as propenone, 2-butenone, and 3-butenone (methyl vinyl ketone); Branched-chain saturated and unsaturated ketones; and Aromatic ketones, such as methyl benzyl ketone (phenylacetone) and ethyl benzyl ketone. It includes. The polymer precursor material may be a combination of the precursors described above.

[0050] In some embodiments, the polymer precursor in a reaction mixture containing little solvent, or essentially solvent-free, is an alcohol-containing species, and the other polymer precursors are carbonyl-containing species. The relative amounts of alcohol-containing species (e.g., alcohols, phenolic compounds, and mono- or poly-hydroxy compounds, or combinations thereof) reacting with carbonyl-containing species (e.g., aldehydes, ketones, or combinations thereof) can vary substantially. In some embodiments, the ratio of alcohol-containing species to aldehyde species is selected such that the total moles of reactive alcohol groups in the alcohol-containing species are approximately equal to the total moles of reactive carbonyl groups in the aldehyde-containing species. Similarly, the ratio of alcohol-containing species to ketone species may be selected such that the total moles of reactive alcohol groups in the alcohol-containing species are approximately equal to the total moles of reactive carbonyl groups in the ketone-containing species. The same general 1:1 molar ratio is maintained even when the carbonyl-containing species include combinations of aldehyde and ketone species.

[0051] In other embodiments, the polymer precursor in a reaction mixture containing little solvent or essentially no solvent 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 a polymer precursor selected from isocyanates or other activated carbonyl compounds (e.g., acid halides).

[0052] Some embodiments of the disclosed methods involve the preparation of a small-solvent or solvent-free polymer gel (and carbon material) containing an electrochemical modifier. Such electrochemical modifiers are not particularly limited, but include, for example, nitrogen, silicon, and sulfur. In other embodiments, the electrochemical modifiers include fluorine, iron, tin, silicon, nickel, aluminum, zinc, or manganese. The electrochemical modifiers may be incorporated at any step during the preparation operation. For example, some electrochemical modifiers are mixed with the mixture, the polymer phase, or a subsequent phase.

[0053] Blending of one or more polymer precursor components in the absence of solvents can be achieved by methods described in the Art, such as ball milling, jet milling, Fritsch milling, planetary mixing, and other mixing methods relating to mixing or blending solid particles while controlling process conditions (e.g., temperature). The mixing or blending process can be achieved before, during, and / or after incubation at the reaction temperature (or a combination thereof).

[0054] 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 and form a polymer. In this regard, a suitable aging temperature ranges from approximately room temperature to the melting point of one or more polymer precursors, or a temperature near thereto. In some embodiments, a suitable aging temperature ranges from approximately room temperature to the glass transition temperature of one or more polymer precursors, or a temperature near thereto. For example, in some embodiments, the solvent-free mixture is aged from about 20°C to about 600°C, for example, about 20°C to about 500°C, for example, about 20°C to about 400°C, for example, about 20°C to about 300°C, for example, about 20°C to about 200°C. In certain embodiments, the solvent-free mixture is aged from about 50°C to 250°C.

[0055] Porous carbon materials can be achieved by the thermal decomposition of polymers produced from the precursor materials described above. In some embodiments, the porous carbon material comprises amorphous activated carbon, which is produced by thermal decomposition, physical or chemical activation, or a combination thereof, in either a single-process or a series of processes.

[0056] The temperature and processing time for pyrolysis can vary; for example, processing times can range from 1 to 10 minutes, 10 to 30 minutes, 30 minutes to 1 hour, 1 to 2 hours, 2 to 4 hours, 4 to 24 hours, etc. The temperature can also vary; for example, pyrolysis temperatures can range 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, etc. Pyrolysis can be achieved in an inert gas (e.g., nitrogen or argon).

[0057] In some embodiments, alternative gases are used to achieve further carbon activation. In certain embodiments, thermal decomposition and activation were performed simultaneously. Suitable gases for achieving carbon activation are not particularly limited but include, for example, carbon dioxide, carbon monoxide, water (water vapor), air, oxygen, and further combinations thereof. The activation temperature and processing time may vary, for example, processing times such as 1 to 10 minutes, 10 to 30 minutes, 30 minutes to 1 hour, 1 to 2 hours, 2 to 4 hours, 4 to 24 hours, etc. The temperature can vary; for example, the thermal decomposition temperature can range 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, and so on.

[0058] The particle size of carbon may be reduced before and / or after thermal decomposition and / or after activation. This reduction in particle size can be achieved by various methods known in the art, such as jet milling in the presence of various gases, including, for example, air, nitrogen, argon, helium, supercritical vapor, and other gases known in the art. Other methods for reducing particle size include grinding, ball milling, jet milling, waterjet milling, and other approaches known in the art.

[0059] The porous carbon scaffold may be in the form of particles. The particle size and particle size distribution can be measured by various methods known in the art and can be expressed based on volume fraction. In this regard, the Dv,50 of the carbon scaffold may be 10 nm to 10 mm, for example 100 nm to 1 mm, for example 1 μm to 100 μm, for example 2 μm to 50 μm, for example 3 μm to 30 μm, for example 4 μm to 20 μm, for example 5 μm to 10 μm, etc. In certain embodiments, the Dv,50 is less than 1 mm, for example less than 100 μm, for example less than 50 μm, for example less than 30 μm, for example less than 20 μm, for example less than 10 μm, for example less than 8 μm, for example less than 5 μm, for example less than 3 μm, for example less than 1 μm, etc. In certain embodiments, Dv,100 is less than 1 mm, for example less than 100 μm, for example less than 50 μm, for example less than 30 μm, for example less than 20 μm, for example less than 10 μm, for example less than 8 μm, for example less than 5 μm, for example less than 3 μm, for example less than 1 μm, etc. In certain embodiments, Dv,99 is less than 1 mm, for example less than 100 μm, for example less than 50 μm, for example less than 30 μm, for example less than 20 μm, for example less than 10 μm, for example less than 8 μm, for example less than 5 μm, for example less than 3 μm, for example less than 1 μm, etc. In certain embodiments, Dv,90 is less than 1 mm, for example less than 100 μm, for example less than 50 μm, for example less than 30 μm, for example less than 20 μm, for example less than 10 μm, for example less than 8 μm, for example less than 5 μm, for example less than 3 μm, for example less than 1 μm, etc. In certain embodiments, Dv,0 is greater than 10 nm, for example, greater than 100 nm, greater than 500 nm, greater than 1 μm, greater than 2 μm, greater than 5 μm, greater than 10 μm, etc. In certain embodiments, Dv,1 is greater than 10 nm, for example, greater than 100 nm, greater than 500 nm, greater than 1 μm, greater than 2 μm, greater than 5 μm, greater than 10 μm, etc. In certain embodiments, Dv,10 is greater than 10 nm, for example, greater than 100 nm, greater than 500 nm, greater than 1 μm, greater than 2 μm, greater than 5 μm, greater than 10 μm, etc.

[0060] In some embodiments, the porous carbon scaffold can have a surface area greater than 400 m 2 / g, such as greater than 500 m 2 / g, such as greater than 750 m 2 / g, such as greater than 1000 m 2 / g, such as greater than 1250 m 2 / g, such as greater than 1500 m 2 / g, such as greater than 1750 m 2 / g, such as greater than 2000 m 2 / g, such as greater than 2500 m 2 / g, such as greater than 3000 m 2 / g, and so on. In other embodiments, the surface area of the porous carbon scaffold can be less than 500 m 2 / g. In some embodiments, the surface area of the porous carbon scaffold is 200 m 2 / g to 500 m 2 / g. In some embodiments, the surface area of the porous carbon scaffold is 100 m 2 / g to 200 m 2 / g. In some embodiments, the surface area of the porous carbon scaffold is 50 m 2 / g to 100 m 2 / g. In some embodiments, the surface area of the porous carbon scaffold is 10 m 2 / g to 50 m 2 / g. In some embodiments, the surface area of the porous carbon scaffold can be less than 10 m 2 / g.

[0061] In some embodiments, the pore volume of the porous carbon scaffold is greater than 0.4 cm 3 / g, such as greater than 0.5 cm 3 / g, such as greater than 0.6 cm 3 / g, such as greater than 0.7 cm 3 / g, such as greater than 0.8 cm<000003​​​​​3 / g or more, for example, 1.2cm 3 / g or more, for example, 1.4cm 3 / g or more, for example, 1.6cm 3 / g or more, for example, 1.8cm 3 / g or more, for example, 2.0cm 3 Examples include values ​​exceeding / g. In other embodiments, the pore volume of the porous silicon scaffold is 0.5 cm³. 3 Less than, for example, 0.1 cm 3 / g~0.5cm 3 The value is / g. In certain embodiments, the pore volume of the porous silicon scaffold is 0.01 cm³. 3 / g~0.1cm 3 It is / g.

[0062] In some embodiments, the porous carbon scaffold is amorphous activated carbon with a pore volume of 0.2–2.0 cm³. 3 The value is / g. In certain embodiments, the carbon is amorphous activated carbon, and its pore volume is 0.4-1.5 cm³. 3 The value is / g. In certain embodiments, the carbon is amorphous activated carbon, and its pore volume is 0.5-1.2 cm³. 3 The value is / g. In certain embodiments, the carbon is amorphous activated carbon, and its pore volume is 0.6-1.0 cm³. 3 It is / g.

[0063] In other embodiments, the porous carbon scaffold is 1.0 g / cm³ 3 Includes tap densities of less than 0.8 g / cm³. 3 Less than, for example, 0.6 g / cm³ 3 Less than, for example, 0.5 g / cm³ 3 Less than, for example, 0.4 g / cm³ 3 Less than, for example, 0.3 g / cm³ 3 Less than, for example, 0.2 g / cm³ 3 Less than, for example, 0.1 g / cm³ 3 Examples include less than, etc.

[0064] The surface functionality of porous carbon scaffolds can vary. One property that can predict the surface functionality is the pH of the porous carbon scaffold. The porous carbon scaffolds disclosed herein include pH values ​​in the range of less than 1 to about 14, for example, less than 5, 5 to 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 less than 1. In other embodiments, the pH of the porous carbon is between about 5 and 6, about 6 to 7, about 7 to 8, 8 to 9, or 9 to 10. In yet other embodiments, the pH of the porous carbon is high, greater than 8, greater than 9, greater than 10, greater than 11, greater than 12, or greater than 13.

[0065] The pore volume distribution of porous carbon scaffolds can vary. For example, the percentage of micropores can include less than 30%, less than 20%, less than 10%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0.2%, less than 0.1%, and so on. In certain embodiments, no detectable micropore volume was present in the porous carbon scaffold.

[0066] The mesopores contained in the porous carbon scaffold can vary. For example, the mesopore percentage can be less than 30%, less than 20%, less than 10%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0.2%, less than 0.1%, and so on. In certain embodiments, no detectable mesopore volume was present in the porous carbon scaffold.

[0067] In some embodiments, the pore volume distribution of the porous carbon scaffold includes more than 50% macropores, for example more than 60% macropores, for example more than 70% macropores, for example more than 80% macropores, for example more than 90% macropores, for example more than 95% macropores, for example more than 98% macropores, for example more than 99% macropores, for example more than 99.5% macropores, for example more than 99.9% macropores, and so on.

[0068] In certain preferred embodiments, the pore volume of the porous carbon scaffold includes a blend of micropores, mesopores, and macropores. Thus, in certain embodiments, the porous carbon scaffold contains 0-20% micropores, 30-70% mesopores, and less than 10% macropores. In other specific embodiments, the porous carbon scaffold contains 0-20% micropores, 0-20% mesopores, and 70-95% macropores. In other specific embodiments, the porous carbon scaffold contains 20-50% micropores, 50-80% mesopores, and 0-10% macropores. In other specific embodiments, the porous carbon scaffold contains 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.

[0069] In certain embodiments, the percentage of pore volume representing pores of 100-1000A (10-100nm) in the porous carbon scaffold includes more than 30% of the total pore volume, for example more than 40% of the total pore volume, for example more than 50% of the total pore volume, for example more than 60% of the total pore volume, for example more than 70% of the total pore volume, for example more than 80% of the total pore volume, for example more than 90% of the total pore volume, for example more than 95% of the total pore volume, for example more than 98% of the total pore volume, for example more than 99% of the total pore volume, for example more than 99.5% of the total pore volume, for example more than 99.9% of the total pore volume.

[0070] In certain embodiments, the pycnometry density of the porous carbon scaffold is in the range of about 1 g / cc to about 3 g / cc, for example, in the range of about 1.5 g / cc to about 2.3 g / cc. In other embodiments, the scaffold density is in the range of about 1.5 g / cc to about 1.6 g / cc, about 1.6 g / cc to about 1.7 g / cc, about 1.7 g / cc to about 1.8 g / cc, about 1.8 g / cc to about 1.9 g / cc, about 1.9 g / cc to about 2.0 g / cc, about 2.0 g / cc to about 2.1 g / cc, about 2.1 g / cc to about 2.2 g / cc, about 2.2 g / cc to about 2.3 g / cc, about 2.3 g / cc to about 2.4 g / cc, and about 2.4 g / cc to about 2.5 g / cc.

[0071] C. Manufacturing of silicon by chemical vapor impregnation (CVI) Chemical vapor deposition (CVD) is a process in which a substrate provides the first component of a composite, and a gas thermally decomposes on the solid surface of the first component to provide the second component of the composite. Such a CVD approach can be used, for example, to fabricate Si-C composite materials in which silicon is coated on the outer surface of silicon particles. Alternatively, chemical vapor infiltration (CVI) is a process in which a substrate provides a porous scaffold containing the first component of a composite, and a gas thermally decomposes within the pores of the porous scaffold material to provide the second component of the composite.

[0072] In one embodiment, silicon is produced within the pores of a porous carbon scaffold by exposing porous carbon particles to a silicon-containing precursor gas at a high temperature and in the presence of a silicon-containing gas, preferably a silane, in order to decompose the silicon-containing gas into silicon. In some embodiments, the silicon-containing gas may include higher silanes (such as di-, tri-, and / or tetrasilanes), chlorosilanes (such as mono-, di-, tri-, and tetrachlorosilanes), or mixtures thereof.

[0073] The silicon-containing precursor gas may be mixed with other inert gases, such as nitrogen gas, hydrogen gas, argon gas, helium gas, or a combination thereof. The processing temperature and time may vary, for example, the temperature may be 200°C to 900°C, 200°C to 250°C, 250°C to 300°C, 300°C to 350°C, 300°C to 400°C, 300°C to 500°C, 350°C to 450°C, 350°C to 400°C, 350°C to 500°C, 350°C to 550°C, 400°C to 500°C, 500°C to 600°C, 600°C to 700°C, 700°C to 800°C, 800°C to 900°C, 600°C to 1100°C, etc.

[0074] The gas mixture may contain 0.1–1% silane and residual inert gas. Alternatively, the gas mixture may contain 1–10% silane and residual inert gas. Alternatively, the gas mixture may contain 10–20% silane and residual inert gas. Alternatively, the gas mixture may contain 20–50% silane and residual inert gas. Alternatively, the gas mixture may contain more than 50% silane and residual inert gas. Alternatively, the gas may contain essentially 100% silane gas. Suitable inert gases include, but are not limited to, hydrogen, nitrogen, argon, and combinations thereof.

[0075] The atmospheric pressure in the CVI process can vary. In some embodiments, the pressure is atmospheric pressure. In some embodiments, the pressure is lower than atmospheric pressure. In some embodiments, the pressure is higher than atmospheric pressure.

[0076] D. Physicochemical and electrochemical properties of silicon-carbon composites While we do not wish to be bound by theory, nano-sized silicon results from filling a porous carbon scaffold with a desired pore volume structure (e.g., silicon-filled pores in the range of 5 nm to 1000 nm, or other ranges of silicon-filled pores disclosed elsewhere herein), which, combined with the favorable properties of the other components of the composite material (including low surface area and low pycnometric density), can result in a composite material with various favorable properties (e.g., electrochemical properties) if the composite includes the anode of a lithium-ion energy storage device.

[0077] In certain embodiments, the silicon particles embedded in the composite have nanoscale properties. The nanoscale properties may have characteristic length scales of preferably less than 1 μm, preferably less than 300 nm, preferably less than 150 nm, preferably less than 100 nm, preferably less than 50 nm, preferably less than 30 nm, preferably less than 15 nm, preferably less than 10 nm, and preferably less than 5 nm.

[0078] In certain embodiments, the silicon embedded in the composite is spherical in shape. In other specific embodiments, the porous silicon particles are non-spherical, for example, in a rod-like or fibrous structure. In some embodiments, the silicon exists as a layer coating the inside of the pores within the porous carbon scaffold. The depth of this silicon layer can vary, for example, 5nm to 10nm, 5nm to 20nm, 5nm to 30nm, 5nm to 33nm, 10nm to 30nm, 10nm to 50nm, 10nm to 100nm, 10nm to 150nm, 50nm to 150nm, 100nm to 300nm, 300nm to 1000nm, and so on.

[0079] In some embodiments, the silicon embedded within the composite is nanosized and resides within the pores of a porous carbon scaffold. For example, the embedded silicon can be impregnated and deposited into the pores within porous carbon particles by CVI or other suitable processes (where the diameter of the pores is 5–1000 nm, e.g., 10–500 nm, e.g., 10–200 nm, e.g., 10–100 nm, e.g., 33–150 nm, e.g., 20–100 nm, etc.). Other ranges of carbon pore size with respect to fragmentary pore volume are similarly assumed, whether they are micropores, mesopores, or macropores.

[0080] In some embodiments, the pore volume distribution of a carbon scaffold can be described as the number of pores or the pore volume distribution, determined based on gas adsorption analysis (e.g., nitrogen gas adsorption analysis) known in the art. In some embodiments, the pore size distribution can be expressed as the pore size in which pores less than or equal to a certain percentage of the total pore volume exist. For example, a pore size in which 10% or less of the pores exist can be expressed as DPv10.

[0081] The DPv10 of a porous carbon scaffold can vary, for example, DPv10 can range from 0.01 nm to 100 nm, 0.1 nm to 100 nm, 1 nm to 100 nm, 1 nm to 50 nm, 1 nm to 40 nm, 1 nm to 30 nm, 1 nm to 10 nm, 1 nm to 5 nm, and so on.

[0082] The DPv50 of the porous carbon scaffold can vary, for example, DPv50 can range from 0.01nm to 100nm, for example from 0.1nm to 100nm, for example from 1nm to 100nm, for example from 1nm to 50nm, for example from 1nm to 40nm, for example from 1nm to 30nm, for example from 1nm to 10nm, for example from 1nm to 5nm, etc. In other embodiments, DPv50 can range from 2nm to 100nm, for example from 2nm to 50nm, for example from 2nm to 30nm, for example from 2nm to 20nm, for example from 2nm to 15nm, for example from 2nm to 10nm, etc.

[0083] The DPv90 of the porous carbon scaffold can vary, for example, DPv90 can range from 0.01nm to 100nm, for example from 0.1nm to 100nm, for example from 1nm to 100nm, for example from 1nm to 50nm, for example from 1nm to 50nm, for example from 1nm to 40nm, for example from 1nm to 30nm, for example from 1nm to 10nm, for example from 1nm to 5nm, etc. In other embodiments, DPv50 can range from 2nm to 100nm, for example from 2nm to 50nm, for example from 2nm to 30nm, for example from 2nm to 20nm, for example from 2nm to 15nm, for example from 2nm to 10nm, etc.

[0084] In some embodiments, DPv90 is less than 100 nm, for example less than 50 nm, for example less than 40 nm, for example less than 30 nm, for example less than 20 nm, for example less than 15 nm, for example less than 10 nm, etc. In some embodiments, the carbon scaffold contains more than 70% micropores and DPv90 less than 100 nm, for example less than 50 nm, for example less than 40 nm, for example less than 30 nm, for example less than 20 nm, for example less than 15 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, etc.

[0085] The DPv99 of the porous carbon scaffold can vary, for example, DPv99 can range from 0.01nm to 1000nm, for example from 0.1nm to 1000nm, for example from 1nm to 500nm, for example from 1nm to 200nm, for example from 1nm to 150nm, for example from 1nm to 100nm, for example from 1nm to 50nm, for example from 1nm to 20nm, etc. In other embodiments, DPv99 is 2nm to 500nm, for example from 2nm to 200nm, for example from 2nm to 150nm, for example from 2nm to 100nm, for example from 2nm to 50nm, for example from 2nm to 20nm, for example from 2nm to 15nm, for example from 2nm to 10nm, etc.

[0086] Embodiments of highly durable lithium intercalation composites disclosed herein improve numerous properties of electrical energy storage devices, such as lithium-ion batteries. In some embodiments, the silicon-carbon composites disclosed herein exhibit a Z of less than 10, for example, less than 5, less than 4, less than 3, less than 2, less than 1, less than 0.1, less than 0.01, less than 0.001, etc. In certain embodiments, Z is 0.

[0087] In certain preferred embodiments, the silicon-carbon composite includes a combination of preferably low Z and other desired physicochemical and / or electrochemical properties, or a combination of several other desired physicochemical and / or electrochemical properties. A description of specific embodiments regarding property combinations of the silicon-carbon composite is shown in Table 1 below.

[0088] Specific characteristics of a silicon-carbon composite embodiment [Table 1]

[0089] According to Table 1, silicon-carbon composites can include various combinations of properties. For example, silicon-carbon composites have a Z of less than 10 and a 100m 2 This may include a surface area of ​​less than 10 / g, a first-cycle efficiency of more than 80%, and a reversible capacity of 1300mAh / g or more. For example, silicon-carbon composites may have a Z of less than 10 and 100m 2 This may include a surface area of ​​less than 10 / g, a first-cycle efficiency of more than 80%, and a reversible capacity of 1600mAh / g or more. For example, a silicon-carbon composite may have a Z of less than 10 and 20m 2 This may include a surface area of ​​less than 10 / g, a first-cycle efficiency of more than 85%, and a reversible capacity of 1600mAh / g or more. For example, a silicon-carbon composite may have a Z of less than 10, 10m 2 This may include a surface area of ​​less than 10 / g, a first-cycle efficiency of more than 85%, and a reversible capacity of 1600mAh / g or more. For example, a silicon-carbon composite may have a Z of less than 10, 10m 2 This may include a surface area of ​​less than 10 / g, a first-cycle efficiency of more than 90%, and a reversible capacity of 1600mAh / g or more. For example, silicon-carbon composites may have a Z of less than 10, 10m 2 This may include a surface area of ​​less than mAh / g, a first-cycle efficiency of more than 90%, and a reversible capacity of 1800mAh / g or more.

[0090] The silicon-carbon composite can include combinations of the above properties, and the carbon scaffold may also include properties similarly described herein. Accordingly, a description of specific embodiments regarding combinations of property values ​​for the silicon-carbon composite is shown in Table 2 below.

[0091] Specific characteristics of a silicon-carbon composite embodiment [Table 2]

[0092] As used herein, the percentages "microporosity," "mesoporosity," and "macroporosity" refer to the proportion of micropores, mesopores, and macropores to the total pore volume, respectively. For example, a carbon scaffold with 90% microporosity is a carbon scaffold in which 90% of the total pore volume is formed by micropores.

[0093] According to Table 2, silicon-carbon composites can include various combinations of property values. For example, silicon-carbon composites have a Z value less than 10 and a 100m value. 2 Surface area less than / g, first cycle efficiency greater than 80%, reversible capacity of 1600mAh / g or more, silicon content of 15% to 85%, total pore volume of 0.2 to 1.2 cm³ 3 The carbon scaffold may contain a carbon scaffold with a pore volume of more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, the silicon-carbon composite may have a Z of less than 10 and a pore volume of 20m 2 Surface area less than / g, first cycle efficiency greater than 85%, reversible capacity of 1600mAh / g or more, silicon content of 15% to 85%, total pore volume of 0.2 to 1.2cm³ 3The carbon scaffold may contain a carbon scaffold with a pore volume of more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, the silicon-carbon composite may have a Z of less than 10 and a pore volume of 10m. 2 Surface area less than / g, first cycle efficiency greater than 85%, reversible capacity of 1600mAh / g or more, silicon content of 15% to 85%, total pore volume of 0.2 to 1.2cm³ 3 The carbon scaffold may contain a carbon scaffold with a pore volume of more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, the silicon-carbon composite may have a Z of less than 10 and a pore volume of 10m. 2 Surface area less than / g, first cycle efficiency greater than 90%, reversible capacity of 1600mAh / g or more, silicon content of 15% to 85%, total pore volume of 0.2 to 1.2cm³ 3 The carbon scaffold may contain a carbon scaffold with a pore volume of more than 80% micropores, less than 20% mesopores, and less than 10% macropores. For example, the silicon-carbon composite may have a Z of less than 10 and a pore volume of 10m. 2 Surface area less than / g, first cycle efficiency greater than 90%, reversible capacity of 1800mAh / g or more, silicon content of 15% to 85%, total pore volume of 0.2 to 1.2cm³ 3 The scaffold may contain carbon scaffolds at a concentration of / g, the pore volume of which includes more than 80% micropores, less than 20% mesopores, and less than 10% macropores.

[0094] Although not bound by theory, filling the pores of porous carbon with silicon traps the pores within the porous carbon scaffold particles, creating inaccessible volumes, such as volumes inaccessible to nitrogen gas. Therefore, silicon-carbon composite materials have a density of 2.1 g / cm³. 3 It shows a pycnometric density of less than 2.0 g / cm³, for example. 3 Less than, for example, 1.9 g / cm³ 3 Less than, for example, 1.8 g / cm³ 3 Less than, for example, 1.7 g / cm³ 3 Less than, for example, 1.6 g / cm³3 less than, for example, 1.4 g / cm 3 less than, for example, 1.2 g / cm 3 less than, for example, 1.0 g / cm 3 less than, etc. may be mentioned.

[0095] In some embodiments, the silicon-carbon composite material may have a pycnometry density of 1.7 g / cm 3 to 2.1 g / cm 3 For example, 1.7 g / cm 3 to 1.8 g / cm 3 For example, 1.8 g / cm 3 to 1.9 g / cm 3 For example, 1.9 g / cm 3 to 2.0 g / cm 3 [[ID=2⑦]]For example, 2.0 g / cm 3 to 2.1 g / cm 3 For example, etc. may be mentioned. In some embodiments, the silicon-carbon composite material may have a pycnometry density of 1.8 g / cm 3 [[ID=③3]]to 2.1 g / cm 3 In some embodiments, the silicon-carbon composite material may have a pycnometry density of 1.8 g / cm[[ID=3⑥]] 3 [[ID=3⑦]]to 2.0 g / cm[[ID=3⑧]] 3 In some embodiments, the silicon-carbon composite material may have a pycnometry density of 1.9 g / cm 3 to 2.1 g / cm 3 The pore volume of the composite material showing very durable lithium intercalation may be 0.01 cm

[0096] / g to 0.2 cm[[ID=4⑧]] 3 / g. In certain embodiments, the pore volume of the composite material may be in the range of 0.01 cm 3 / g to 0.15 cm 3 / g, for example, 0.01 cm 3 / g to 0.1 cm 3 / g, for example, 0.01 cm 3 / g to 0.05 cm 3 / g, for example, etc. may be mentioned. 3 / g, etc. may be mentioned.

[0097] The particle size distribution of the composite material showing highly durable lithium intercalation is equally important for both power performance and volume capacity. With improved packing, the volume capacity may also increase. In one embodiment, the distribution is either a Gaussian distribution with a sharp single peak, bimodal, or polymodal (more than two distinguishable peaks, e.g., trimodal). The characteristic values of the particle size of the composite can be described by Dv0 (the smallest particle within the distribution), Dv50 (the average particle size), and Dv100 (the maximum size of the largest particle). The optimal combination of particle packing and performance is a combination within the following size ranges. The reduction of the particle size in such embodiments can be carried out, as known in the art, for example, by a jet mill in the presence of various gases. Such gases include, for example, air, nitrogen, argon, helium, supercritical steam, and other gases known in the art.

[0098] In one embodiment, the Dv0 of the composite material can be in the range of 1 nm to 5 μm. In other embodiments, the Dv0 of the composite is in the range of 5 nm to 1 μm, for example, 5 to 500 nm, for example, 5 to 100 nm, for example, 10 to 50 nm. In other embodiments, the Dv0 of the composite is in the range of 500 nm to 2 μm, for example, 750 nm to 1 μm, or 1 to 2 μm. In other embodiments, the Dv0 of the composite is 2 to 5 μm, or greater than 5 μm.

[0099] In some embodiments, the Dv50 of the composite material is in the range of 5 nm to 20 μm. In other embodiments, the Dv50 of the composite is in the range of 5 nm to 1 μm, for example 5 to 500 nm, for example 5 to 100 nm, for example 10 to 50 nm. In other embodiments, the Dv50 of the composite is in the range of 500 nm to 2 μm, 750 nm to 1 μm, or 1 to 2 μm. In yet further embodiments, the Dv50 of the composite is in the range of 1 to 1000 μm, for example 1 to 100 μm, for example 1 to 10 μm, for example 2 to 20 μm, for example 3 to 15 μm, for example 4 to 8 μm. In certain embodiments, the Dv50 is greater than 20 μm, for example greater than 50 μm, for example greater than 100 μm.

[0100] The span is represented by the following formula: (Dv50) / (Dv90-Dv10) [Here, Dv10, Dv50, and Dv90 represent the particle sizes at 10%, 50%, and 90% of the volume distribution, respectively.] The span can vary, for example, from 100 to 10, 10 to 5, 5 to 2, or 2 to 1. In some embodiments, the span may be less than 1. In certain embodiments, the particle size distribution of the composite containing carbon and porous silicon material may be multimodal (e.g., bimodal or trimodal).

[0101] The surface functionality of composite materials exhibiting highly durable lithium intercalation, as disclosed herein, may be modified to obtain desired electrochemical properties. One property that can predict surface functionality is the pH of the composite material. The composite materials disclosed herein include pH ranges from less than 1 to about 14, for example, 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 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 other further embodiments, the pH of the composite material is high, with pH greater than 8, greater than 9, greater than 10, greater than 11, greater than 12, or greater than 13.

[0102] Silicon-carbon composite materials can contain varying amounts of carbon, oxygen, hydrogen, and nitrogen, which can be measured by CHNO analysis using gas chromatography. In one embodiment, the carbon content of the composite is greater than 98% by weight or greater than 99.9% by weight, as measured by CHNO analysis. In another embodiment, the carbon content of the silicon-carbon composite is in the range of 10 to 90% by weight, for example, 20 to 80% by weight, for example, 30 to 70% by weight, for example, 40 to 60% by weight, etc.

[0103] In some embodiments, the silicon-carbon composite material has a nitrogen content in the range of 0 to 90%, for example, 0.1 to 1%, 1 to 3%, 1 to 5%, 1 to 10%, 10 to 20%, 20 to 30%, or 30 to 90%.

[0104] In some embodiments, the oxygen content is in the range of 0 to 90%, such as 0.1 to 1%, 1 to 3%, 1 to 5%, 1 to 10%, 10 to 20%, 20 to 30%, 30 to 90%, and so on.

[0105] Silicon-carbon composite materials may incorporate electrochemical modifiers selected to optimize the electrochemical properties of the unmodified composite. The electrochemical modifiers may be introduced in the pore structure and / or on the surface of the porous carbon scaffold, within embedded silicon, or within the final layer of carbon, or by conductive polymers, coatings, or numerous other methods. For example, in some embodiments, the composite material includes a coating of the electrochemical modifier (e.g., silicon, or Al2O3) on the surface of the carbon material. In some embodiments, the composite material contains more than about 100 ppm of the electrochemical modifier. In certain embodiments, the electrochemical modifier is selected from iron, tin, silicon, nickel, aluminum, and manganese.

[0106] In certain embodiments, the electrochemical modifier comprises elements (e.g., silicon, tin, sulfur) that have the ability to lithiate lithium metal at 3 to 0 V. In other embodiments, the electrochemical modifier comprises metal oxides (e.g., iron oxide, molybdenum oxide, titanium oxide) that have the ability to lithiate lithium metal at 3 to 0 V. In further embodiments, the electrochemical modifier comprises elements (e.g., aluminum, manganese, nickel, metal phosphates) that do not lithiate lithium metal at 3 to 0 V. In further embodiments, the electrochemical modifier comprises nonmetallic elements (e.g., fluorine, nitrogen, hydrogen). In further embodiments, the electrochemical modifier comprises any of the above electrochemical modifiers, or any combination thereof (e.g., tin-silicon, nickel-titanium oxide).

[0107] 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 iron, tin, silicon, nickel, or manganese. In other embodiments, the electrochemical modifier comprises one or more elements in oxide form, such as iron oxide, tin oxide, silicon oxide, nickel oxide, aluminum oxide, or manganese oxide.

[0108] The electrochemical properties of a composite material can be modified, at least partially, by the amount of electrochemical modifier in the material. Here, the electrochemical modifier is an alloy material such as silicon, tin, indium, aluminum, germanium, or gallium. Accordingly, in some embodiments, the composite material contains 0.10% or more, 0.25% or more, 0.50% or more, 1.0% or more, 5.0% or more, 10% or more, 25% or more, 50% or more, 75% or more, 90% or more, 95% or more, 99% or more, or 99.5% or more of the electrochemical modifier.

[0109] The particle size of the composite material may expand upon lithiation compared to the unlithified state. For example, the expansion coefficient is defined as the ratio of the average particle size of the composite material containing the porous silicon material during lithiation to the average particle size under non-lithified conditions. As described in the Art, the above expansion coefficient is relatively large for known, suboptimal silicon-containing materials, for example, about 4X (corresponding to a 400% volume expansion during lithiation). The inventors have found composite materials containing porous silicon material that can exhibit lower expansion coefficients, for example, a range of 3.5-4.0, 3.0-3.5, 2.5-3.0, 2.0-2.5, 1.5-2.0, and 1.0-1.5.

[0110] In certain embodiments, the composite material is assumed to include a portion of the trapped pore volume, i.e., a portion of the void volume that is inaccessible to nitrogen gas. Here, the void volume can be measured by nitrogen gas adsorption measurements. Although not bound by theory, this trapped pore volume is important in that it provides a volume to which silicon can expand during lithiation.

[0111] In certain embodiments, the ratio of the trapped void volume to the silicon volume containing the composite particles is 0.1:1 to 10:1. For example, the ratio of the trapped void volume to the silicon volume containing the composite particles is 1:1 to 5:1, or 5:1 to 10:1. In some embodiments, the ratio of the trapped void volume to the silicon volume containing the composite particles is between 2:1 and 5:1, or about 3:1, which can efficiently accommodate the maximum expansion of silicon during lithiation.

[0112] In certain embodiments, the electrochemical performance of the composites disclosed herein is tested in half-cells; otherwise, the performance of composites with highly durable lithium intercalations disclosed herein is tested in full cells (e.g., a full-cell coin cell, a full-cell pouch cell, a prismatic cell, or battery configurations known in the art). The anode configurations of composites with highly durable lithium intercalations disclosed herein include a variety of types, as known in the art. Further formulation components are not particularly limited but may include conductive additives such as conductive carbon (e.g., Super C45, Super P, and Ketjenblack carbon), conductive polymers, and binders (e.g., styrene-butadiene rubber sodium carboxymethylcellulose (SBR-Na-CMC), polyvinylidene fluoride (PVDF), polyimide (PI), and polyacrylic acid (PAA)), and combinations thereof. In certain embodiments, the binder may contain lithium ions as counterions.

[0113] Other types, including electrodes, are known in the art. The weight percentage of the active material in the electrode can vary, for example, 1-5% by weight, 5-15% by weight, 15-25% by weight, 25-35% by weight, 35-45% by weight, 45-55% by weight, 55-65% by weight, 65-75% by weight, 75-85% by weight, 85-95% by weight, and so on. In some embodiments, the active material makes up 80-95% of the electrode. In certain embodiments, the amount of the conductive additive in the electrode can vary, for example, 1-5% by weight, 5-15% by weight, 15-25% by weight, 25-35% by weight, and so on. In some embodiments, the amount of the conductive additive in the electrode is 5-25% by weight. In certain embodiments, the amount of binder may vary, for example, 1-5% by weight, 5-15% by weight, 15-25% by weight, 25-35% by weight, etc. In certain embodiments, the amount of conductive additive in the electrode is 5-25% by weight.

[0114] Silicon-carbon composite materials are pre-lithiated, as is known in the art. In certain embodiments, pre-lithiation is achieved electrochemically, for example, in a half-cell prior to the construction of a lithiated anode containing porous silicon material in a full-cell lithium-ion battery. In certain embodiments, pre-lithiation is achieved by doping the cathode with a lithium-containing compound (e.g., a lithium-containing salt). Suitable lithium salts in this embodiment are not particularly limited, but include, for example, dilithium tetrabromonickel(II)ate, dilithium tetrachlorocopper(II)ate, lithium azide, lithium benzoate, lithium bromide, lithium carbonate, lithium chloride, lithium cyclohexane butyrate, lithium fluoride, lithium formate, lithium hexafluoroarsenate(V), lithium hexafluorophosphate, lithium hydroxide, lithium iodate, lithium metaborate, lithium perchlorate, lithium phosphate, lithium sulfate, lithium tetraborate, lithium tetrachloroaluminate, lithium tetrafluoroborate, lithium thiocyanate, lithium trifluoromethanesulfonate, and combinations thereof.

[0115] Anodes containing silicon-carbon composite materials can be paired with various cathode materials to produce full-cell lithium-ion batteries. Examples of suitable cathode materials are known in the art. Such cathode materials are not particularly limited, but include, for example, LiCoO2 (LCO), LiNi 0.8 Co 0.15 Al 0.05 O2(NCA), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Examples include O2 (NMC), LiMn2O4 and its variants (LMO), and LiFePO4 (LFP).

[0116] Regarding a full cell lithium-ion battery including an anode further comprising a silicon-carbon composite material, the pair of cathode and anode can be various. For example, the ratio of the capacities of the cathode and anode can vary from 0.7 to 1.3. In certain embodiments, the ratio of the capacities of the cathode and anode can vary from 0.7 to 1.0, for example, from 0.8 to 1.0, for example, from 0.85 to 1.0, for example, from 0.9 to 1.0, for example, from 0.95 to 1.0. In other embodiments, the ratio of the capacities of the cathode and anode can vary from 1.0 to 1.3, for example, from 1.0 to 1.2, for example, from 1.0 to 1.15, for example, from 1.0 to 1.1, for example, from 1.0 to 1.05, etc. In still other embodiments, the ratio of the capacities of the cathode and anode can vary from 0.8 to 1.2, for example, from 0.9 to 1.1, for example, from 0.95 to 1.05, etc.

[0117] Regarding a full cell lithium-ion battery including an anode further comprising a silicon-carbon composite material, the voltage window during charging and discharging can be various. In this regard, the voltage window can be various according to various characteristics of the lithium-ion battery, as is known in the art. For example, as is known in the art, the selection of the cathode plays a role in the selected voltage window. The voltage window is various. For example, for the potential with respect to Li / Li+, it is 2.0V to 5.0V, for example, 2.5V to 4.5V, 2.5V to 4.2V, etc.

[0118] Regarding a full cell lithium-ion battery including an anode further comprising a silicon-carbon composite material, the cell conditioning method can be various, as is known in the art. For example, conditioning can be achieved by performing a plurality of charge and discharge cycles at various rates, for example, at a rate slower than the desired cycle rate. As is known in the art, the conditioning process may further include the steps of opening the lithium-ion battery, discharging all the gases generated during the conditioning process, and subsequently resealing the lithium-ion battery.

[0119] With respect to a full-cell lithium-ion battery including an anode further comprising a silicon-carbon composite material, the cycle rate may vary as is known in the art, for example, the rate may be C / 20 to 20C, for example C / 10 to 10C, for example C / 5 to 5C, etc. In a particular embodiment, the cycle rate is C / 10. In a particular embodiment, the cycle rate is C / 5. In a particular embodiment, the cycle rate is C / 2. In a particular embodiment, the cycle rate is 1C. In a particular embodiment, the cycle rate is 1C with a periodic decrease to a slower rate (for example, applying a decrease of C / 10 every 20 cycles). In a particular embodiment, the cycle rate is 2C. In a particular embodiment, the cycle rate is 4C. In a particular embodiment, the cycle rate is 5C. In a particular embodiment, the cycle rate is 10C. In a particular embodiment, the cycle rate is 20C.

[0120] The first-cycle efficiency of the highly durable lithium intercalation composite disclosed herein was measured by comparing the amount of lithium inserted into the anode during the first cycle with the amount of lithium extracted from the anode during the first cycle, prior to pre-lithiation. When insertion and extraction are equal, the efficiency is 100%. As is known in the art, the anode material can be tested in a half-cell, where the counter electrode of the half-cell is lithium metal, the electrolyte is 1 M LiPF6 and 1:1 ethylene carbonate:diethyl carbonate (EC:DEC), and it can be tested in a half-cell using a commercially available polypropylene separator. In certain embodiments, the electrolyte may contain various additives known to improve performance, such as fluoroethylene carbonate (FEC) or other related fluorinated carbonate compounds, or ester cosolvents (e.g., methyl butanoate, vinylene carbonate, etc.), and other additives known to improve the electrochemical performance of silicon-containing anode materials.

[0121] Coulomb efficiency can be averaged, for example, in half-cell testing, it can be averaged over cycles 7 to 25. In certain embodiments, the average efficiency of a composite with very durable lithium intercalation is greater than 0.9 or greater than 90%. In certain embodiments, the average efficiency is greater than 0.95 or greater than 95%. In certain embodiments, the average efficiency is 0.99 or higher, for example, 0.991 or higher, 0.992 or higher, 0.993 or higher, 0.994 or higher, 0.995 or higher, 0.996 or higher, 0.997 or higher, 0.998 or higher, 0.999 or higher, 0.9991 or higher, 0.9992 or higher, 0.9993 or higher, 0.9994 or higher, 0.9995 or higher, 0.9996 or higher, 0.9997 or higher, 0.9998 or higher, 0.9999 or higher, and so on.

[0122] In further other embodiments, the disclosure herein provides composite materials exhibiting highly durable lithium intercalation. Here, the composite material, when introduced into electrodes of a lithium-based energy storage device, has a volumetric capacity that is 10% or more higher than when introduced into electrodes of a lithium-based energy storage device containing graphite electrodes. In some embodiments, the lithium-based energy storage device is a lithium-ion battery. In some embodiments, the composite material has a volumetric capacity in a lithium-based energy storage device that is 5% or more, 10% or more, or 15% or more higher than a similar electrical energy storage device having graphite electrodes. In further other embodiments, the composite material has a volumetric capacity in a lithium-based energy storage device that is 20% or more, 30% or more, 40% or more, 50% or more, 200% or more, 100% or more, 150% or more, or 200% or more higher than a similar electrical energy storage device having graphite electrodes.

[0123] The composite material may be pre-lithiated as is known in the art. These lithium atoms may or may not be separable from carbon. The number of lithium atoms relative to six carbon atoms is determined by the following formula, which is known to those skilled in the art: #Li=Q×3.6×MM / (C%×F) [Here, Q is the lithium extraction capacity (mAh / g) measured at a voltage of 5mV to 2.0V relative to lithium metal, MM is the molecular mass of 72 or 6 carbon atoms, F is the Faraday constant (96500), and C% is the weight percentage of carbon present in the structure, measured by CHNO or XPS.] It can be calculated by [method].

[0124] Composite materials can be characterized by the ratio of lithium atoms to carbon atoms (Li:C), which may be approximately 0:6 to 2:6. In some embodiments, Li:C is approximately 0.05:6 and 1.9:6. In other embodiments, lithium is in ionic form and not metallic form, and the maximum Li:C ratio is 2.2:6. In other specific embodiments, the Li:C ratio is approximately 1.2:6 to approximately 2:6, approximately 1.3:6 to approximately 1.9:6, approximately 1.4:6 to approximately 1.9:6, approximately 1.6:6 to approximately 1.8:6, or approximately 1.7:6 to approximately 1.8:6. In other embodiments, the Li:C ratio is greater than 1:6, greater than 1.2:6, greater than 1.4:6, greater than 1.6:6, or greater than 1.8:6. In further other embodiments, the Li:C ratio is about 1.4:6, about 1.5:6, about 1.6:6, about 1.7:6, about 1.8:6, or about 2:6. In certain embodiments, the Li:C ratio is about 1.78:6.

[0125] In certain embodiments, the composite material includes Li:C ratios in the range of approximately 1:6 to approximately 2.5:6, approximately 1.4:6 to approximately 2.2:6, or approximately 1.4:6 to approximately 2:6. In further other embodiments, the composite material does not necessarily have to contain lithium, but instead has lithium uptake capacity, i.e., the ability to absorb a certain amount of lithium, during the material's cycle between two voltage conditions (for lithium-ion half-cells, a typical voltage window is 0 to 3V, e.g., 0.005 to 2.7V, e.g., 0.005 to 1V, e.g., 0.005 to 0.8V, etc.). While we do not wish to be bound by theory, the lithium uptake capacity of the composite material contributes to superior performance in lithium-based energy storage devices. Lithium uptake capacity is expressed as the ratio of lithium atoms replaced by the composite. In other specific embodiments, composite materials exhibiting highly durable lithium intercalation include lithium uptake capacities ranging from about 1:6 to about 2.5:6, about 1.4:6 to about 2.2:6, or about 1.4:6 to about 2:6, etc.

[0126] In certain other embodiments, the lithium uptake capacity ranges from approximately 1.2:6 to approximately 2:6, approximately 1.3:6 to approximately 1.9:6, approximately 1.4:6 to approximately 1.9:6, approximately 1.6:6 to approximately 1.8:6, or approximately 1.7:6 to approximately 1.8:6, etc. In other embodiments, the lithium uptake capacity is greater than 1:6, greater than 1.2:6, greater than 1.4:6, greater than 1.6:6, or greater than 1.8:6. In yet another embodiment, the Li:C ratio is approximately 1.4:6, approximately 1.5:6, approximately 1.6:6, approximately 1.6:6, approximately 1.7:6, approximately 1.8:6, or approximately 2:6. In a particular embodiment, the Li:C ratio is approximately 1.78:6.

[0127] Examples Example 1. Manufacturing of silicon-carbon composite material by CVI. The characteristics of the carbon scaffold (carbon scaffold 1) used in the manufacturing of the silicon-carbon composite are shown in Table 3 below. Using carbon scaffold 1, the silicon-carbon composite (silicon-carbon composite 1) was manufactured by CVI as follows: 0.2 grams of amorphous porous carbon was placed in a 2-inch x 2-inch ceramic crucible and positioned in the center of a horizontal tubular furnace. The furnace was sealed and continuously purged with nitrogen gas at 500 cubic centimeters (ccm) per minute. The furnace temperature was raised at 20°C per minute to a peak temperature of 450°C and maintained for 30 minutes. At this point, the nitrogen was shut off, followed by the introduction of silane and hydrogen at flow rates of 50 ccm and 450 ccm, respectively, over a total of 30 minutes. Then, the silane and nitrogen were shut off, nitrogen was reintroduced into the furnace, and the internal air was purged. At the same time, the furnace heating was stopped and it was allowed to cool down to ambient temperature. After that, the finished Si-C material was removed from the furnace.

[0128] Description of the carbon scaffold used in Example 1 [Table 3]

[0129] Example 2. Analysis of various silicon-composite materials. Various carbon scaffold materials were used, and the carbon scaffold materials were characterized by nitrogen adsorption gas analysis to measure specific surface area, total pore volume, and the ratio of pore volume including micropores, mesopores, and macropores. The characterization data of the carbon scaffold materials, i.e., the surface area, pore volume, and pore volume distribution (percentage of micropores, percentage of mesopores, and percentage of macropores) of the carbon scaffolds (all measured by nitrogen adsorption analysis), are shown in Table 4.

[0130] Characteristics of various carbon scaffold materials [Table 4]

[0131] Using the carbon scaffold samples listed in Table 4, various silicon-carbon composite materials were fabricated by the CVI method in a static bed configuration, as generally described in Example 1. These silicon-carbon samples were fabricated under the following process conditions: silane concentration of 1.25% to 100%; dilution gas of nitrogen or hydrogen; and starting mass of carbon scaffold of 0.2g to 700g.

[0132] The surface area of ​​the silicon-carbon composite was measured. Furthermore, the silicon content and Z of the silicon-carbon composite were determined by TGA analysis. Testing of the silicon-carbon composite material was also performed using a half-cell coin cell. The anode of the half-cell coin cell can contain 60-90% silicon-carbon composite, 5-20% Na-CMC (as a binder), and 5-20% Super C45 (as a conductivity enhancer), and the electrolyte can contain 2:1 ethylene carbonate:diethylene carbonate, 1M LiPF6, and 10% fluoroethylene carbonate. The half-cell coin cell can be cycled for 5 cycles at 25°C and a rate of C / 5, and then cycled at a rate of C / 10. The voltage can be cycled from 0V to 0.8V, and separately, from 0V to 1.5V. From the data of half-cell and coin cells, the maximum capacity can be measured, and similarly, the average Coulomb efficiency (CE) from cycle 7 to cycle 20 can also be measured. The physicochemical and electrochemical properties of various silicon-carbon composite materials are shown in Table 5 below.

[0133] Property values ​​of various silicon-carbon materials [Table 5]

[0134] Figure 1 shows a plot of the average Coulomb efficiency as a function of Z. As can be seen, the average Coulomb efficiency increased dramatically in silicon-carbon samples with low Z. In particular, all silicon-carbon samples with Z less than 10.0 showed an average Coulomb efficiency of 0.9941 or higher, and all silicon-carbon samples with Z greater than 10 (silicon-carbon composite samples 12 to 16) were observed to have an average Coulomb efficiency of 0.9909 or lower. Although not bound by theory, the higher Coulomb efficiency in silicon-carbon samples with Z less than 10 provides superior cycle stability in full-cell lithium-ion batteries. Further investigation of the table revealed a surprising and unexpected result: a combination of silicon-carbon composite samples with Z less than 10 and silicon-carbon composite samples further containing carbon scaffolds with microporosity greater than 69.1 showed an average Coulomb efficiency of 0.9969 or higher.

[0135] Therefore, in a more preferred embodiment, the silicon-carbon composite material includes Z less than 10, for example Z less than 5, for example Z less than 3, for example Z less than 2, for example Z less than 1, for example Z less than 0.5, for example Z less than 0.1, or Z 0.

[0136] In certain preferred embodiments, the silicon-carbon composite material comprises a carbon scaffold having a Z of less than 10 and a microporosity of more than 70%, for example, a Z of less than 10 and a microporosity of more than 80%, for example, a Z of less than 10 and a microporosity of more than 90%, for example, a Z of less than 10 and a microporosity of more than 95%, for example, a Z of less than 5 and a microporosity of more than 70%, for example, a Z of less than 5 and a microporosity of more than 80%, for example, a Z of less than 5 and a microporosity of more than 90%, for example, a Z of less than 3 and a microporosity of more than 70%, for example, a Z of less than 3 and a microporosity of more than 80%, for example, a Z of less than 3 and a microporosity of more than 95%, for example, a Z of less than 2 and a microporosity of more than 70%, for example, a Z of less than 2 and a microporosity of more than 80%, for example, a Z of less than 2 and a microporosity of more than 90%, for example, a Z of less than 2 Microporosity of more than 95% of Z, e.g., Z less than 1 and more than 70% of Z, e.g., Z less than 1 and more than 80% of Z, e.g., Z less than 1 and more than 90% of Z, e.g., Z less than 1 and more than 95% of Z, e.g., Z less than 0.5 and more than 70% of Z, e.g., Z less than 0.5 and more than 80% of Z, e.g., Z less than 0.5 and more than 90% of Z, e.g., Z less than 0.5 and more than 95% of Z Examples of microporosity include Z less than 0.1 and microporosity greater than 70%, Z less than 0.1 and microporosity greater than 80%, Z less than 0.1 and microporosity greater than 90%, Z less than 0.1 and microporosity greater than 95%, Z 0 and microporosity greater than 70%, Z 0 and microporosity greater than 80%, Z 0 and microporosity greater than 90%, Z 0 and microporosity greater than 95%, and so on.

[0137] In certain preferred embodiments, the silicon-carbon composite material has a Z of less than 10, a microporosity of more than 70%, silicon content of 15% to 85%, and 100m 2Includes a surface area of ​​less than / g, for example, Z less than 10, microporosity greater than 70%, silicon 15% to 85%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 15% to 85%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 15% to 85%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 15% to 85%, and 5m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 15% to 85%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 15% to 85%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 15% to 85%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 15% to 85%, and 5m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 90%, silicon 15% to 85%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 90%, silicon 15% to 85%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 90%, silicon 15% to 85%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 90%, silicon 15% to 85%, and 5m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 15% to 85%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 15% to 85%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon between 15% and 85%, and 10m 2Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 15% to 85%, and 5m 2 Examples include a surface area of ​​less than / g.

[0138] In certain preferred embodiments, the silicon-carbon composite material has a Z of less than 10, a microporosity of more than 70%, a silicon content of 30% to 60%, and 100m 2 Includes a surface area of ​​less than / g, for example, Z less than 10, microporosity greater than 70%, silicon 30% to 60%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 30% to 60%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 30% to 60%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 70%, silicon 30% to 60%, and 5m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 30% to 60%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 30% to 60%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 30% to 60%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 80%, silicon 30% to 60%, and 5m 2 Surface area less than / g, e.g., Z less than 10, microporosity more than 90%, silicon 30% to 60%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity more than 90%, silicon 30% to 60%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity more than 90%, silicon 30% to 60%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity more than 90%, silicon 30% to 60%, and 5m 2Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 30% to 60%, and 50m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 30% to 60%, and 30m 2 Surface area less than / g, e.g., Z less than 10, microporosity greater than 95%, silicon 30% to 60%, and 10m 2 Surface area less than / g, e.g., Z less than 10, microporosity more than 95%, silicon 30% to 60%, and 5m 2 Examples include a surface area of ​​less than / g.

[0139] Example 3. dV / dQ in silicon-composite materials. Differential capacitance curves (dQ / dv vs voltage) are commonly used as a non-destructive tool to understand phase transitions as a function of voltage in lithium battery electrodes (MN Obrovac et al. Structural Changes in Silicon Anodes during Lithium Insertion / Extraction, Electrochemical and Solid-State Letters, 7 (5) A93-A96 (2004); Ogata, K. et al. Revealing lithium-silicide phase transformations in nano-structured silicon-based lithium ion batteries via in situ NMR spectroscopy. Nat. Commun. 5:3217). The differential capacitance plots shown herein were calculated from data obtained by galvanostatic cycling at a 0.1C rate and 5mV–0.8V in a half-cell coin cell at 25°C.Typical differential capacity curves for silicon-based materials versus lithium in half-cells can be found in numerous references (Loveridge, MJ et al. Towards High Capacity Li-Ion Batteries Based on Silicon-Graphene Composite Anodes and Sub-micron V-doped LiFePO4 Cathodes. Sci. Rep. 6, 37787; doi: 10.1038 / srep37787 (2016); MN Obrovac et al. Li15Si4Formation in Silicon Thin Film Negative Electrodes, Journal of The Electrochemical Society, 163 (2) A255-A261 (2016); Q.Pan et al. Improved electrochemical performance of micro-sized SiO-based composite anode by prelithiation of stabilized lithium metal powder, Journal of Power Sources 347 (2017) 170-177). The lithiation behavior in the first cycle depends on several factors, including the crystallinity of silicon and its oxygen content.

[0140] After the first cycle, the amorphous silicon material in the art exhibits two specific phase transition peaks in the dQ / dV vs V plot for lithiation, and similarly, two specific phase transition peaks in the dQ / dV vs V plot for delithiation. Regarding lithiation, one peak corresponds to the poor lithium Li-Si alloy phase occurring at 0.2–0.4V, and the other peak corresponds to the lithium-rich Li-Si alloy phase occurring below 0.15V. Regarding delithiation, one delithiation peak corresponds to the extraction of lithium occurring below 0.4V, and the other delithiation peak occurs at 0.4V–0.55V. 15When the Si4 phase is formed, it is delithiated at approximately 0.45 V, resulting in a very narrow and sharp peak.

[0141] Figure 2 shows the dQ / dV vs voltage curve in cycle 2 for a silicon-carbon composite material corresponding to silicon-carbon composite 3 of Example 1. Silicon-carbon composite 3 contains Z at 0.6. For ease of identification, the plots are divided into regimes I, II, III, IV, V, and VI. Regimes I (0.8V~0.4V), II (0.4V~0.15V), and III (0.15V~0V) include the lithiation potential, while regimes IV (0V~0.4V), V (0.4V~0.55V), and VI (0.55V~0.8V) include the delithiation potential. As described above, the earlier amorphous silicon-based materials in the art showed phase transition peaks at the lithiation potential in two regimes (regimes II and III), and phase transition peaks at the delithiation potential in two regimes (regimes IV and V).

[0142] As can be seen from Figure 2, the dQ / dV vs voltage curve revealed a surprising and unexpected result: silicon-carbon composite 3, containing Z 0.6, also exhibits two more peaks in the dQ / dV vs V curve, namely in regime 1 at the lithiation potential and regime VI at the delithiation potential. As shown in Figure 3, all six peaks are reversible and are similarly observed in subsequent cycles.

[0143] While not constrained by theory, this trimodal behavior in the dQ / dV vs V curve is novel and reflects a new form of silicon.

[0144] In particular, the novel peaks observed in regimes I and VI are more pronounced in certain scaffold matrices and are completely absent in other samples indicating prior art (silicon-carbon composite samples with Z greater than 10; see description and table below).

[0145] Figure 4 shows the dQ / dV vs V curve for silicon-carbon composite 3, which exhibits clear novel peaks in regimes I and VI. In contrast, Figure 4 also shows the dQ / dV vs V curves for silicon-carbon composites 15, 16, and 14 (all three samples containing Z values ​​greater than 10), which lack any peaks in regimes I and VI.

[0146] Although not bound by theory, these novel peaks observed in regimes I and VI relate to the properties of silicon impregnated in porous carbon scaffolds, i.e., to the interactions and properties between the porous carbon scaffold, the silicon impregnated in the porous carbon scaffold by CVI, and lithium. To provide a quantitative analysis, the inventors have derived the following equation as peak I normalized with respect to peak III: φ = (Maximum peak height dQ / dV in Regime I) / (Maximum peak height dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with regime 1 being 0.8V to 0.4V and regime III being 0.15V to 0V; the half-cell coin cell was manufactured as known in the art.] The parameter φ, which is calculated using the formula, was defined. If a Si-C sample shows a graphite-related peak in regime III of the differential curve, the Li-Si-related phase transition peak for the calculation of coefficient D is given priority, and the former peak is removed. In this example, the half-cell coin cell contains an anode with 60-90% silicon-carbon composite, 5-20% SBR-Na-CMC, and 5-20% Super C45. An example of the calculation of φ for silicon-carbon composite 3 is shown in Figure 5. In this example, the maximum peak height in regime I was -2.39, found at 0.53V. Similarly, the maximum peak height in regime III was -9.71 at 0.04V. In this example, φ can be obtained by the above formula, and φ = -2.39 / -9.71 = 0.25 was obtained. The value of φ was obtained from half-cell coin cell data for various silicon-carbon composites shown in Example 2. These data are summarized in Table 6.

[0147] Property values ​​of various silicon-carbon materials [Table 6] *The parenthetical data for the first cycle efficiency were measured within a potential window of 5mV to 1.5V.

[0148] The data in Table 6 revealed an unexpected relationship between decreasing Z and increasing φ. All silicon-carbon composites with Z less than 10 had a φ of 0.13 or greater, and all silicon-carbon composites with Z greater than 10 had a φ of less than 0.13. Conversely, all silicon-carbon composites with Z greater than 10 had a φ of 0. This relationship is also clearly shown in Figure 6. Although not bound by theory, silicon materials containing a φ of 0.10 or greater (e.g., φ of 0.13 or greater) correspond to a novel form of silicon. Separately, silicon materials containing a φ greater than 0 correspond to a novel form of silicon. Although not bound by theory, silicon materials containing a φ greater than 0 are characteristic of silicon materials that are amorphous, nano-sized, or silicon trapped in pores (e.g., in the pores of porous carbon scaffolds). Silicon-carbon composite materials containing silicon with a φ of 0.10 or greater (e.g., φ of 0.13 or greater) correspond to novel silicon-carbon composite materials. Aside from that, silicon-carbon composite materials containing a diameter greater than 0 correspond to novel silicon-carbon composite materials.

[0149] In certain embodiments, the silicon-carbon composite includes φ of 0.1 or greater, φ of 0.11 or greater, φ of 0.12 or greater, φ of 0.13 or greater, φ of 0.14 or greater, φ of 0.15 or greater, φ of 0.16 or greater, φ of 0.17 or greater, φ of 0.18 or greater, φ of 0.19 or greater, φ of 0.20 or greater, φ of 0.24 or greater, φ of 0.24 or greater, φ of 0.25 or greater, φ of 0.30 or greater, or φ of 0.35 or greater. In some embodiments, φ is greater than 0. In some embodiments, φ is 0.001 or greater, φ is 0.01 or greater, φ is 0.02 or greater, φ is 0.05 or greater, φ is 0.1 or greater, φ is 0.11 or greater, or φ is 0.12 or greater.

[0150] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 70%, containing 30-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 70%, silicon content of 30-60%, and 50m2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, silicon 30-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, silicon 30-60%, 10m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0151] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 70%, containing 40-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 70%, silicon 40-60%, 50m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 10m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0152] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 70%, containing 30-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 70%, silicon 30-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 30-60%, 30m 2Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 30-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 30-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0153] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 70%, containing 40-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 70%, silicon 40-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 70%, silicon 40-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0154] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 80%, containing 30-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 80%, silicon content of 30-60%, and 50m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 80%, silicon 30-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 80%, silicon 30-60%, 10m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 80%, silicon content 30-60%, 5m2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0155] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 80%, containing 40-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 80%, silicon content of 40-60%, and 50m 2 Surface area less than / g, φ greater than 0.1, for example Z less than 10, microporosity greater than 80%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 80%, silicon 40-60%, 10m 2 Surface area less than / g, φ greater than 0.1, for example Z less than 10, microporosity greater than 80%, silicon 40-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0156] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 80%, containing 30-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 80%, silicon 30-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 30-60%, 30m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 30-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 30-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0157] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 80%, containing 40-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 80%, silicon 40-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 40-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 80%, silicon 40-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0158] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 90%, containing 30-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 90%, silicon content of 30-60%, and 50m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon content 30-60%, 30m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon content 30-60%, 10m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon content 30-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0159] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 90%, containing 40-60% silicon, and 100m 2Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 90%, silicon 40-60%, 50m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 10m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0160] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 90%, containing 30-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 90%, silicon 30-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 30-60%, 30m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 30-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 30-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0161] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 90%, containing 40-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 90%, silicon 40-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 30m2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 90%, silicon 40-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0162] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 95%, containing 30-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 95%, silicon content of 30-60%, and 50m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 5, microporosity greater than 95%, silicon 30-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 95%, silicon 30-60%, 10m 2 Surface area less than / g, φ greater than 0.1, for example Z less than 10, microporosity greater than 95%, silicon 30-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0163] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 95%, containing 40-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 95%, silicon content of 40-60%, and 50m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 95%, silicon content 40-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 95%, silicon 40-60%, 10m 2Surface area less than / g, φ greater than 0.1, for example Z less than 10, microporosity greater than 95%, silicon 40-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0164] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 95%, containing 30-60% silicon, and 100m 2 Includes a surface area of ​​less than / g and a diameter of 0.1 or greater, for example, Z less than 10, microporosity greater than 95%, silicon content of 30-60%, and 50m 2 Surface area less than / g, and diameter greater than 0.1, e.g., Z less than 10, microporosity greater than 95%, silicon content 30-60%, 30m 2 Surface area less than / g, and φ greater than 0.1, e.g., Z less than 10, microporosity greater than 95%, silicon 30-60%, 10m 2 Surface area less than / g, φ greater than 0.1, for example Z less than 10, microporosity greater than 95%, silicon 30-60%, 5m 2 Examples include a surface area of ​​less than / g and a diameter of 0.1 or greater.

[0165] In certain embodiments, the silicon-carbon composite material is a carbon scaffold with a Z of less than 10 and a microporosity of more than 95%, containing 40-60% silicon, and 100m 2 Includes a surface area less than / g and a φ greater than 0, for example, Z less than 10, microporosity greater than 95%, silicon 40-60%, 50m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 95%, silicon 40-60%, 30m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 95%, silicon 40-60%, 10m 2 Surface area less than / g, and φ greater than 0, e.g., Z less than 10, microporosity greater than 95%, silicon 40-60%, 5m 2 Examples include a surface area less than / g and a φ greater than 0.

[0166] Example 4. Particle size distribution of various carbon scaffold materials. The particle size distribution of various carbon scaffold materials was measured using a laser diffraction particle size analyzer, which is known in the art. In particular, the data for Dv1, Dv10, Dv50, Dv90, and Dv100 are shown in Table 7.

[0167] Characteristics of various carbon scaffold materials [Table 7]

[0168] Example 5. Effects of CVI process variables on the fractional conversion of silicon-containing gas to silicon element in the production of various silicon-composite materials. Table 8 shows some important CVI process parameters used in the production of various silicon-carbon materials. As an example, two types of reactors were used: a static bed (SB) type and a horizontally moving bed (HMB) type. Here, the SB type is a type in which a layer (bed) of porous carbon scaffold is fixed and permanently present within the heating zone of the reactor, while the HMB type is a type in which a layer (bed) of porous carbon traverses the hot zone of the reactor horizontally. Silicon-carbon composite samples 4, 5, 7, and 8 were produced using the HMB configuration, while all other silicon-carbon composite samples listed in Table 8 were produced using the SB configuration. Other types of manufacturing equipment are also possible. In other embodiments, the type of CVI reactor may vary; for example, the CVI reactor may be a vibro-thermal assisted CVI (VTA-CVI) reactor. In other embodiments, the type of CVI reactor may be a convection-thermal assisted CVI (CTA-CVI) reactor. In other embodiments, the type of CVI reactor may be a rotating CVI kiln. In other embodiments, the type of CVI reactor may be a fluidized bed CVI (FB-CVI) reactor. In the example of the present invention, the CVI process was carried out in a batch process for 1 to 6 hours. In other embodiments, the CVI process can be carried out in a semi-batch process. In certain embodiments, the CVI process can be carried out in a continuous process.

[0169] Characteristics of various carbon scaffold materials [Table 8] *Sample 24 had its silane flow rate changed. Therefore, Y in this case... CVI This was calculated as the total number of moles of silane per hour, that is, the total number of moles of silane transferred to the CVI reactor divided by the total reaction time of the CVI reactor.

[0170] As shown in Table 8, the CVI temperature for the samples produced in this example was varied within the range of 400°C to 525°C. The CVI process can also be performed in other temperature ranges, such as 350°C to 550°C, 350°C to 500°C, 350°C to 450°C, 375°C to 450°C, 380°C to 450°C, 385°C to 450°C, 390°C to 450°C, and so on.

[0171] Furthermore, as shown in Table 8, the silicon-containing precursor gas used in the samples prepared in this example was silane, and the concentration of silane as a mass fraction of the total gas composition was varied in the range of 1.25% to 100% by mass. In the samples prepared by mixing silane gas with a diluent gas, the diluent gas was changed to either hydrogen (H2) or nitrogen (N2). Other diluent gases are also conceivable, such as argon.

[0172] The CVI process may be carried out in a gas containing 100% silane introduced into the CVI reactor. Alternatively, the gas introduced into the CVI reactor may contain less than 100% silane and diluent gases (including hydrogen, nitrogen, argon, or a combination thereof).

[0173] Furthermore, as shown in Table 8, for the sample produced in this example, the mass per unit area of ​​the starting carbon scaffold material within the layer was 0.0039 g / cm³. 2 ~0.5434 g / cm³ 2The value was varied within this range. In other conceivable embodiments, the mass per unit area of ​​the starting carbon scaffold material within the layer may vary, for example, 0.001 g / cm³. 2 ~10g / cm 2 Examples include the above. In other embodiments, the mass per unit area of ​​the starting carbon scaffold material in the layer may vary, for example, 1 g / cm³. 2 ~5g / cm 2 Examples include the above. In other conceivable embodiments, the mass per unit area of ​​the starting carbon scaffold material in the layer may vary, for example, 5 g / cm³. 2 ~10g / cm 2 , for example. In other conceivable embodiments, the mass per unit area of ​​the starting carbon scaffold material in the layer is 10 g / cm³. 2 It is possible.

[0174] Aside from that, the mass per unit area of ​​the starting carbon scaffold material within the layer can vary, for example, 0.0001 g / cm³. 2 ~1g / cm 2 For example, the mass per unit area of ​​the starting carbon scaffold material within the layer may vary, such as 0.001 g / cm³. 2 ~1g / cm 2 , 0.002 g / cm³ 2 ~1g / cm 2 , 0.003 g / cm³ 2 ~1g / cm 2 , 0.004 g / cm³ 2 ~1g / cm 2 , or 0.005 g / cm³ 2 ~1g / cm 2 Examples include, etc. In some embodiments, the mass per unit area of ​​the starting carbon scaffold material in the layer is 0.001 g / cm³. 2 ~1g / cm 2 It can vary between these two values.

[0175] Furthermore, as shown in Table 8, the silane flow rate to the reactor for the samples prepared in this example can be normalized with respect to the carbon scaffold. Therefore, the silane flow rate normalized by the silane flow rate can vary. Since 1 mole of silane gas contains 1 mole of silicon, it can also be stated that the carbon scaffold normalized by the silicon flow rate can vary. The process parameter is given by the following formula: Y CVI = (Number of moles of silicon introduced into the CVI reactor per hour) / (Number of moles of carbon scaffold in the CVI reactor) It is represented as follows.

[0176] In the embodiments of the present invention, the silicon-containing gas used in the CVI process is silane, and each silane contains 1 mole of silicon per mole, therefore, apart from the above formula, the following formula: Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold in the CVI reactor) It can also be expressed as follows.

[0177] A surprising and unexpected result concerns the use of silane gas during the CVI process to prepare silicon-carbon composites. The percentage of this use is given by the following formula: X Si = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silicon raw material) It can be defined as follows. In the above formula, the number of moles of silicon in the silicon-carbon composite is determined from the percentage of silicon in the silicon-carbon composite by thermogravimetric analysis after the completion of the CVI process. Also, with respect to this measurement, the number of moles of silicon raw material is the total number of moles of silicon introduced into the CVI reactor in the form of silicon-containing gas during the CVI process, which converts the porous carbon scaffold and silicon-containing gas into a silicon-carbon composite. In embodiments where the silicon-containing gas is silane, there is 1 mole of silicon per mole of silane. Thus XSi The formula is as follows: X Si = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silane raw material) It can also be expressed as follows.

[0178] In certain embodiments, the silane flow rate is kept constant during the CVI reaction. In this case, Y CVI The number of moles of silane per hour used in the calculation is the molar silane flow rate (in mol / h). In some embodiments, the silane flow is not constant and is varied, for example, stepwise and / or ramped. In some embodiments, the silane flow rate is lower at the start and end of the CVI reaction. If the flow rate is not constant, Y CVI Y is calculated as the total number of moles of silane per hour. For example, Y is calculated by dividing the total number of moles of silane introduced into the CVI reactor by the time of the CVI reaction. CVI It is calculated.

[0179] X Si The data is shown in Table 8. As can be seen from Table 8, Y CVI As X decreases Si It increases dramatically (Figure 7). In some embodiments of manufacturing silicon-carbon composites by CVI, Y CVI is less than 1, and X Si It is over 50%. In a preferred embodiment for producing silicon-carbon composites by CVI, Y CVI is less than 0.5, and X Si It is over 50%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.4 and X Si It is over 60%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.3 and X SiIt is over 70%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.2 and X Si It is over 70%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.3 and X Si It is over 80%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.2 and X Si It is over 80%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.3 and X Si It is over 85%. In a more preferred embodiment, Y is used to produce silicon-carbon composites by CVI. CVI is less than 0.2 and X Si It is over 85%. In a more preferred embodiment, Y is used to produce silicon-carbon composites by CVI. CVI is less than 0.3 and X Si It is over 90%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.2 and X Si It is over 90%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.3 and X Si It is over 95%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.2 and X Si It is over 95%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.2 and X Si It is over 99%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.1 and X Si It is over 90%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVIis less than 0.1 and X Si It is over 95%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.1 and X Si It is over 99%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.05, and X Si It is over 90%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.05, and X Si It is over 95%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.05, and X Si It is over 99%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.01, and X Si It is over 90%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.01, and X Si It is over 95%. In a more preferred embodiment, Y is used to produce the silicon-carbon composite by CVI. CVI is less than 0.01, and X Si It is over 99%.

[0180] Example 6. In-line process monitoring of silane utilization in the CVI process measured by Fourier transform infrared spectroscopy (FTIR). Fourier transform infrared spectroscopy (FTIR) is a suitable method for quantifying the gas concentration of silane gas in its gaseous form. For this purpose, in the preparation of silicon-carbon composite 21, the gas exiting the reactor was introduced into an airtight FTIR cell in an FTIR spectrophotometer. The silane concentration % exiting the reactor, i.e., the silane concentration as the ratio of the silane concentration entering the reactor, was measured at 979 cm⁻¹ in the FTIR spectrum of the gas exiting the reactor. -1The peak height was measured, and this value was used as the FTIR spectrum for the control, i.e., unreacted silane gas, at 979 cm⁻¹. -1 The value was obtained by dividing by the peak height and then multiplying this value by 100 to convert it to a percentage. The silane utilization % was calculated by subtracting the silane concentration % exiting the above reactor from 100. Figure 8 shows the inline process data for silane utilization % as a function of preparation time for sample 21. As can be read from Figure 8, the maximum utilization % is 98%. Although not bound by theory, based on the analysis of the above example, the silane flow rate during the start and end phases of the CVI reaction phase can be adjusted, i.e., reduced, to improve the silane utilization rate during the above phases. In this way, X Si It increases further, for example X Si is over 85%, or X Si is over 90%, or X Si is over 95%, or X Si It becomes over 98%. Although not bound by theory, these data are for a continuous reactor, and X is over 98%. Si This demonstrates the feasibility of executing the CVI process in a reactor where this is achievable.

[0181] Example 7. CVI process including recycling or recycling with a purge stream. The process for producing silicon-carbon composite particles may include a recycle stream. Thus, the gas exiting the CVI reactor may include unreacted silane gas, hydrogen gas (generated from the reacted silane), and diluent gas (if used), and this gas stream may be reintroduced as one or more feed streams back into the CVI reactor. In certain embodiments, the CVI reactor includes multiple zones, and the silane recycle stream may be supplied to one or more zones of the CVI reactor as one or more feed streams. In certain embodiments, the recycle stream includes a purge stream. Thus, any hydrogen or diluent gas present in the recycle stream can be separated from the silane present in the recycle stream, for example, by gas separation techniques such as distillation or membrane gas separation. The use of such a recycle stream, or a recycle stream with puring, increases the tilization of the net silane, resulting in X Si It exceeds 50%, for example, over 60%, over 70%, over 85%, over 90%, over 95%, over 98%, over 99%.

[0182] Details of the embodiment Embodiment 1. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold to a temperature between 350°C and 550°C; Y less than c.0.5 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method SiHowever, it must be more than 50%. Here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Methods that include...

[0183] Embodiment 2. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; Y less than c.0.5 CVI To provide a silane gas corresponding to Y, where Y CVI Y CVI It is calculated from the formula = (number of moles of silane per hour) / (number of moles of carbon scaffold); and d. X in this method Si However, the percentage is over 50%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) [In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.] Calculated from, e. Silicon-carbon composites including the following: i. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from. Methods that include...

[0184] Embodiment 3. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; Y less than c.0.5 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 50%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. φ greater than or equal to 0.1, where said φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0185] Embodiment 4. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; Y less than c.0.5 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 50%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. Silicone content of 30% to 60% by weight; ii. Z less than 10, where Z is, Z = 1.875 × [(M1100 - M) / M1100] × 100%, (wherein, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; iii. 30m 2 Surface area less than / g; and iv. 0.1 or greater φ, where φ is, φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) Calculated from, Methods that include...

[0186] Embodiment 5. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.4 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 60%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, Methods that include...

[0187] Embodiment 6. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.4CVI To provide a silane gas corresponding to Y. CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 60%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. Silicon-carbon composites, including the following: e. Z less than 10, where Z is: Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from. Methods that include...

[0188] Embodiment 7. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.4 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI= (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 60%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. φ greater than or equal to 0.1, where φ is: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0189] Embodiment 8. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.4 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 60%, and here, X Si teeth, X Si= 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. Silicone content of 30% to 60% by weight; ii. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; iii. 30m 2 Surface area less than / g; and iv. 0.1 or greater φ, where φ is, φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0190] Embodiment 9. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 70%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, Methods that include...

[0191] Embodiment 10. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI It is calculated from the formula = (number of moles of silane per hour) / (number of moles of carbon scaffold); and d. X in this method Si However, the percentage is over 70%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from. Methods that include...

[0192] Embodiment 11. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI It is calculated from the formula = (number of moles of silane per hour) / (number of moles of carbon scaffold); and d. X in this method Si However, the percentage is over 70%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. φ greater than or equal to 0.1, where φ is: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0193] Embodiment 12. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 70%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. Silicone content of 30% to 60% by weight; ii. Z less than 10, where Z is, Z = 1.875 × [(M1100 - M) / M1100] × 100%, (wherein, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; iii. 30m 2 Surface area less than / g; and iv. 0.1 or greater φ, where φ is, φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0194] Embodiment 13. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y. CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, it must be over 85%. Here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, Methods that include...

[0195] Embodiment 14. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, it is over 85%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) Calculated from, Methods that include...

[0196] Embodiment 15. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, it is over 85%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. φ greater than or equal to 0.1, where said φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) Calculated from, Methods that include...

[0197] Embodiment 16. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, it must be over 85%. Here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. Silicone content of 30% to 60% by weight; ii. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; iii. 30m 2 Surface area less than / g; and iv. φ greater than or equal to 0.1. Here, φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0198] Embodiment 17. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 90%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, Methods that include...

[0199] Embodiment 18. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 90%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) Calculated from, Methods that include...

[0200] Embodiment 19. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y, where Y CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, the percentage is over 90%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, e. Silicon-carbon composites including the following: i. φ greater than or equal to 0.1, where said φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) Calculated from, Methods that include...

[0201] Embodiment 20. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 70% microporosity; b. Heat the porous carbon scaffold from 350°C to 550°C; c. Y less than 0.2 CVI To provide a silane gas corresponding to Y. CVI teeth, Y CVI = (Number of moles of silane per hour) / (Number of moles of carbon scaffold) Calculated from; and d. X in this method Si However, it must be over 90%. Here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) It is calculated from. e. Silicon-carbon composites including the following: i. Silicone content of 30% to 60% by weight; ii. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; iii. 30m 2 Surface area less than / g; and iv. 0.1 or greater φ, where said φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) Calculated from, Methods that include...

[0202] Embodiment 21. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 20, which include microporosity with a pore volume of more than 80%.

[0203] Embodiment 22. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 21, which include microporosity with a pore volume of more than 90%.

[0204] Embodiment 23. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 22, which include microporosity with a pore volume of more than 95%.

[0205] Embodiment 24. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 23, wherein the temperature is 400°C to 525°C.

[0206] Embodiment 25. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 24, wherein the silicon-carbon composite contains 40 to 60% silicon.

[0207] Embodiment 26. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 25, wherein Z is less than 5.

[0208] Embodiment 27. Surface area of ​​10 m² 2 A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 26, wherein the particle size is less than / g.

[0209] Embodiment 28. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 27, wherein the silicon-carbon composite contains a φ of 0.2 or more. Here, the above φ is calculated from the formula φ = (maximum peak height of dQ / dV in regime I) / (maximum peak height of dQ / dV in regime III), (wherein dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V).

[0210] Embodiment 29. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 28, wherein the silicon-carbon composite contains a φ of 0.3 or more. Here, the above φ is calculated from the formula φ = (maximum peak height of dQ / dV in regime I) / (maximum peak height of dQ / dV in regime III), (wherein dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V).

[0211] Embodiment 30. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 29, wherein the silicon-carbon composite contains Dv50 particles ranging from 5 nm to 20 microns.

[0212] Embodiment 31. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 30, wherein the silicon-carbon composite has a capacity of more than 900 mA / g.

[0213] Embodiment 32. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 31, wherein the silicon-carbon composite has a capacity of more than 1300 mA / g.

[0214] Embodiment 33. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 32, wherein the silicon-carbon composite has a capacity of more than 1600 mA / g.

[0215] Embodiment 34. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 33, wherein the method is a batch process.

[0216] Embodiment 35. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 34, wherein the method is a continuous process.

[0217] Embodiment 36. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 35, wherein the type of reactor is a static bed reactor, a horizontally moving bed reactor, a vibrating heat-assisted reactor, a convection heat-assisted reactor, or a fluidized bed reactor.

[0218] Embodiment 37. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 36, wherein the silane concentration as a mass fraction of the total gas composition is 1.25% to 100%.

[0219] Embodiment 38. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 36, wherein the gas comprises a silane and an inert gas (selected from nitrogen, hydrogen, argon, or helium, or a combination thereof).

[0220] Embodiment 39. The mass per unit area of ​​the carbon scaffold is 0.001 g / cm³. 2 ~10g / cm 2A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 38.

[0221] Embodiment 40. An energy storage device comprising a silicon-carbon composite manufactured by the method described in any one of Embodiments 1 to 39.

[0222] Embodiment 41. A lithium-ion battery comprising a silicon-carbon composite manufactured by the method described in any one of Embodiments 1 to 39.

[0223] Embodiment 42. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold having a pore volume including one or more micropores and one or more mesopores; b. Heating the porous carbon scaffold from 350°C to 550°C in the presence of silane gas; and c. X in this method Si However, it must be more than 50%. Here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, Methods that include...

[0224] Embodiment 43. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold having a pore volume including one or more micropores and one or more mesopores; b. Heat the porous carbon scaffold to 350°C to 550°C in the presence of silane gas; c. X in this method Si However, it must be more than 50%. Here, X SiX Si The formula is calculated as follows: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) d. Silicon-carbon composites including the following: ii. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) Calculated from, Methods that include...

[0225] Embodiment 44. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold having a pore volume including one or more micropores and one or more mesopores; b. Heat the porous carbon scaffold to 350°C to 550°C in the presence of silane gas; c. X in this method Si However, the percentage is over 50%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, d. Silicon-carbon composites including the following: ii. 0.1 or greater φ, where said φ is φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) It is calculated from. Methods that include...

[0226] Embodiment 45. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold having a pore volume including one or more micropores and one or more mesopores; b. Heat the porous carbon scaffold to 350°C to 550°C in the presence of silane gas; c. X in this method Si However, the percentage is over 50%, and here, X Si teeth, X Si = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material) (In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis.) Calculated from, d. Silicon-carbon composites including the following: v. Silicone content of 30% to 70% by weight; vi. Z less than 10, where Z is, Z=1.875×[(M1100-M) / M1100]×100%, (In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.) It is calculated from; vii.30m 2 Surface area less than / g; and viii. 0.1 A φ greater than or equal to, where the φ is, φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) (In the formula, dQ / dV is measured in a half-cell coin cell, with regime I being 0.8V to 0.4V and regime III being 0.15V to 0V.) Calculated from, Methods that include...

[0227] Embodiment 46.X Si A method for producing silicon-carbon composite particles according to Embodiment 42, wherein X is more than 60%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0228] Embodiment 47.X Si A method for producing silicon-carbon composite particles according to Embodiment 43, wherein X is more than 60%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0229] Embodiment 48.X Si A method for producing silicon-carbon composite particles according to Embodiment 44, wherein X is more than 60%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0230] Embodiment 49.X Si A method for producing silicon-carbon composite particles according to Embodiment 45, wherein X is more than 60%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0231] Embodiment 50.X Si A method for producing silicon-carbon composite particles according to Embodiment 42, wherein X is more than 70%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0232] Embodiment 51.X Si A method for producing silicon-carbon composite particles according to Embodiment 43, wherein X is more than 70%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0233] Embodiment 52.X Si A method for producing silicon-carbon composite particles according to Embodiment 44, wherein X is more than 70%. Si X SiThe result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0234] Embodiment 53.X Si A method for producing silicon-carbon composite particles according to Embodiment 45, wherein X is more than 70%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0235] Embodiment 54.X Si A method for producing silicon-carbon composite particles according to Embodiment 42, wherein X is more than 85%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0236] Embodiment 55.X Si A method for producing silicon-carbon composite particles according to Embodiment 43, wherein X is more than 85%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0237] Embodiment 56.X SiA method for producing silicon-carbon composite particles according to Embodiment 44, wherein X is more than 85%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0238] Embodiment 57.X Si A method for producing silicon-carbon composite particles according to Embodiment 45, wherein X is more than 85%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0239] Embodiment 58.X Si A method for producing silicon-carbon composite particles according to Embodiment 42, wherein X is more than 90%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0240] Embodiment 59.X Si A method for producing silicon-carbon composite particles according to Embodiment 43, wherein X is more than 90%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0241] Embodiment 60.X Si A method for producing silicon-carbon composite particles according to Embodiment 44, wherein X is more than 90%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0242] Embodiment 61.X Si A method for producing silicon-carbon composite particles according to Embodiment 45, wherein X is more than 90%. Si X Si The result is calculated using the following formula: = 100 × (number of moles of silicon in the silicon-carbon composite) / (number of moles of silane raw material), (wherein the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content in the silicon-carbon composite by thermogravimetric analysis).

[0243] Embodiment 62. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 61, wherein the silane gas includes a recycled flow.

[0244] Embodiment 63. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 61, wherein the silane gas includes a recycle flow including a purge flow.

[0245] Embodiment 64. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 75% when measured in a voltage window of 5mV to 0.8V in a half-cell.

[0246] Embodiment 65. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 80% when measured in a half-cell within a voltage window of 5mV to 0.8V.

[0247] Embodiment 66. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 85% when measured in a half-cell within a voltage window of 5mV to 1.5V.

[0248] Embodiment 67. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 90% when measured in a half-cell within a voltage window of 5mV to 1.5V.

[0249] Embodiment 68. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 91% when measured in a half-cell within a voltage window of 5mV to 1.5V.

[0250] Embodiment 69. A method for producing silicon-carbon composite particles according to any one of Embodiments 1 to 64, wherein the silicon-carbon composite particles have a first-cycle efficiency of more than 92% when measured in a half-cell within a voltage window of 5mV to 1.5V.

[0251] From the above, it will be understood that while specific embodiments of the present invention have been described herein for disclosure purposes, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, the present invention is not limited except as provided for in the appended claims.

[0252] All U.S. patents, U.S. patent publications, and U.S. patent applications, patents and patent applications of other countries, and non-patent literature referenced herein and / or included in the application datasheet (including, but not limited to, U.S. Patent Application Publication No. 2016 / 996694, U.S. Provisional Patent Application No. 63 / 075566, U.S. Patent Application Publication No. 2017 / 336104, and U.S. Provisional Patent Application No. 63 / 078806) are incorporated herein by reference in their entirety.

Claims

1. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with more than 70% microporosity; b. Heating the porous carbon scaffold from 350°C to 550°C; c. Carbon scaffold with a Y value of less than 0.5 ＣＶＩ Contacting the corresponding silane raw material gas, where Y ＣＶＩ The formula is as follows: Y ＣＶＩ = (Number of moles of silane feedstock gas per hour) / (Number of moles of carbon scaffold) Represented by; and d. X Ｓｉ However, it is more than 60%, where the above X Ｓｉ The formula is as follows: X Ｓｉ = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silane feedstock gas) [In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content of the silicon-carbon composite by thermogravimetric analysis.] Represented by, Methods that include...

2. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with more than 70% microporosity; b. Heating the porous carbon scaffold from 350°C to 550°C; c. Carbon scaffold with a Y of less than 0.3 ＣＶＩ Contacting the corresponding silane raw material gas, where Y ＣＶＩ The formula is as follows: Y ＣＶＩ = (number of moles of silane source gas per hour) / (number of moles of carbon scaffold) Represented by; and d. X Ｓｉ However, it is more than 70%, where X Ｓｉ The formula is as follows: X Ｓｉ = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silane feedstock gas) [In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content of the silicon-carbon composite by thermogravimetric analysis.] Represented by, Methods that include...

3. X Ｓｉ The percentage is over 85%, and here, X Ｓｉ The formula is as follows: X Ｓｉ = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silane feedstock gas) [In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content of the silicon-carbon composite by thermogravimetric analysis.] Represented by, A method for producing silicon-carbon composite particles according to claim 2.

4. A method for producing silicon-carbon composite particles, the following: a. To provide a carbon scaffold containing a pore volume with over 90% microporosity; b. Heating the porous carbon scaffold from 350°C to 550°C; c. Carbon scaffold with a Y of less than 0.3 ＣＶＩ Contacting the corresponding silane raw material gas, where Y ＣＶＩ The formula is as follows: Y ＣＶＩ = (Number of moles of silane feedstock gas per hour) / (Number of moles of carbon scaffold) Represented by; and d. X Ｓｉ However, it is more than 85%, where the above X Ｓｉ The formula is as follows: X Ｓｉ = 100 × (Number of moles of silicon in the silicon-carbon composite) / (Number of moles of silane feedstock gas) [In the formula, the number of moles of silicon in the silicon-carbon composite is determined from the silicon content of the silicon-carbon composite by thermogravimetric analysis.] Represented by, e. Silicon-carbon composite particles including the following: i. Silicon content of 40% to 60% by weight; ii. Z less than 10, where Z is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.] It is represented by; iii. 30m ２ Surface area less than / g; and iv. φ of 0.1 or greater, where φ is given by the following formula: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with Regime I being 0.8V to 0.4V and Regime III being 0.15V to 0V.] Represented by, Methods that include...

5. A method for producing silicon-carbon composite particles according to claim 1, wherein the pore volume includes microporosity of more than 90%.

6. A method for producing silicon-carbon composite particles according to claim 2, wherein the pore volume includes microporosity of more than 90%.

7. A method for producing silicon-carbon composite particles according to claim 3, wherein the pore volume includes microporosity of more than 90%.

8. Silicon-carbon composite particles, 10m ２ A method for producing silicon-carbon composite particles according to claim 1, comprising a surface area of ​​less than 1 g.

9. Silicon-carbon composite particles, 10m ２ A method for producing silicon-carbon composite particles according to claim 2, comprising a surface area of ​​less than 1g.

10. Silicon-carbon composite particles, 10m ２ A method for producing silicon-carbon composite particles according to claim 3, comprising a surface area of ​​less than 1g.

11. Silicon-carbon composite particles, 10m ２ A method for producing silicon-carbon composite particles according to claim 4, comprising a surface area of ​​less than 1g.

12. A method for producing silicon-carbon composite particles according to claim 1, wherein the silicon-carbon composite particles contain a D 50 in the range of 5 nm to 20 microns.

13. A method for producing silicon-carbon composite particles according to claim 2, wherein the silicon-carbon composite particles contain a D50 in the range of 5 nm to 20 microns.

14. A method for producing silicon-carbon composite particles according to claim 3, wherein the silicon-carbon composite particles contain a D50 in the range of 5 nm to 20 microns.

15. A method for producing silicon-carbon composite particles according to claim 4, wherein the silicon-carbon composite particles contain a D50 in the range of 5 nm to 20 microns.

16. The silicon-carbon composite particles contain Z less than 10, where Z is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.] Represented by, A method for producing silicon-carbon composite particles according to claim 1.

17. A method in which the silicon-carbon composite particles contain a φ of 0.1 or more. Here, the φ is given by the following formula: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with Regime I being 0.8V to 0.4V and Regime III being 0.15V to 0V.] Represented by, A method for producing silicon-carbon composite particles according to claim 1.

18. The silicon-carbon composite particles are as follows: a. Silicon content of 40% to 60% by weight; b. Z less than 10, where Z is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.] It is represented by; c. 30m ２ Surface area less than / g; and d. φ of 0.1 or greater, where φ is given by the following formula: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with Regime I being 0.8V to 0.4V and Regime III being 0.15V to 0V.] It is represented as follows. A method for producing silicon-carbon composite particles according to claim 1, including the method described in claim 1.

19. The silicon-carbon composite particles are as follows: a. Silicon content of 40% to 60% by weight; b. Z less than 10. Here, Z is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.] It is represented by; c. 30m ２ Surface area less than / g; and d. φ of 0.1 or greater. Here, φ is given by the following formula: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with Regime I being 0.8V to 0.4V and Regime III being 0.15V to 0V.] It is represented as follows. A method for producing silicon-carbon composite particles according to claim 2, including the method described in claim 2.

20. The silicon-carbon composite particles are as follows: a. Silicon content of 40% to 60% by weight; b. Z less than 10, where Z is given by the following formula: Z=1.875×[(M1100-M) / M1100]×100% [In the formula, when the silicon-carbon composite is heated in air from approximately 25°C to approximately 1100°C, M1100 is the mass of the silicon-carbon composite at 1100°C, and M is the minimum mass of the silicon-carbon composite between 800°C and 1100°C. These masses are determined by thermogravimetric analysis.] It is represented by; c. 30m ２ Surface area less than / g; and d. φ of 0.1 or greater, where φ is given by the following formula: φ = (Maximum peak height of dQ / dV in Regime I) / (Maximum peak height of dQ / dV in Regime III) [In the formula, dQ / dV is measured in a half-cell coin cell, with Regime I being 0.8V to 0.4V and Regime III being 0.15V to 0V.] It is represented as follows. A method for producing silicon-carbon composite particles according to claim 3, including the method described in claim 3.

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