Electroactive material for metal ion battery

Abstract

To provide electroactive material-containing composite particles that overcome defects of composite particles obtained from conventional single-step and multi-step deposition processes and a method for preparing the same.SOLUTION: A particulate material is composed of a plurality of composite particles. The composite particles include a porous particle framework containing micropores and / or mesopores. A total pore volume of micropores and mesopores measured by gas adsorption ranges 0.4 cm3 / g to 2.2 cm3 / g. The composite particles include a plurality of electroactive material domains and a plurality of modifier material domains disposed within an internal pore volume of a porous particle framework. At least part of modifier material domains is located between adjacent electroactive material domains.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates generally to electroactive materials suitable for use in electrodes for rechargeable metal-ion batteries, and more particularly to particulate materials having high electrochemical capacity suitable for use as anode active materials in rechargeable metal-ion batteries. [Background technology]

[0002] Rechargeable metal-ion batteries are widely used in portable electronic devices such as cell phones and laptops, and are increasingly finding application in electric or hybrid vehicles. Rechargeable metal-ion batteries generally include an anode in the form of a metal current collector with a layer of electroactive material, defined herein as a material capable of inserting and releasing metal ions during charging and discharging of the battery. The terms "cathode" and "anode" are used herein to mean that the battery is under load such that the anode is negative. When a metal-ion battery is charged, metal ions are transported from the metal-ion-containing cathode layer through the electrolyte to the anode and inserted into the anode material. The term "battery" is used herein to refer to both devices containing a single anode and a single cathode, as well as devices containing multiple anodes and / or multiple cathodes.

[0003] There is interest in improving the gravimetric and / or volumetric capacity of rechargeable metal-ion batteries. To date, commercially available lithium-ion batteries have been primarily limited to the use of graphite as the anode active material. Upon charging a graphite anode, lithium is intercalated between the graphite layers, forming a compound with the empirical formula Li xC6, where x is greater than 0 and equal to or less than 1. As a result, graphite has a maximum theoretical capacity of 372 mAh / g in lithium-ion batteries, with practical capacities somewhat lower (approximately 340 mAh / g to 360 mAh / g). Other materials, such as silicon, tin, and germanium, can intercalate lithium at significantly higher capacities than graphite, but are not yet in widespread commercial use due to the difficulty of maintaining sufficient capacity over many charge-discharge cycles.

[0004] In particular, silicon has been recognized as a promising alternative to graphite in the production of rechargeable metal-ion batteries with high gravimetric and volumetric capacities due to its extremely high capacity relative to lithium (see, for example, Non-Patent Document 1). Silicon has a theoretical maximum specific capacity of about 3600 mAh / g (Li ) in lithium-ion batteries at room temperature. 15 The anode is a silicon anode (based on silicon dioxide). However, when lithium is intercalated into bulk silicon, the volume of the silicon material increases significantly, up to 400% of its original volume when silicon is lithiated to its maximum capacity. Repeated charge-discharge cycles generate significant mechanical stresses on the silicon material, leading to fracture and delamination of the silicon anode material. The volumetric shrinkage of silicon particles during delithiation can result in loss of electrical contact between the anode material and the current collector. To make matters worse, the solid electrolyte interfacial (SEI) layer formed on the silicon surface is not mechanically durable enough to accommodate the expansion and contraction of the silicon. As a result, the newly exposed silicon surface leads to further electrolyte decomposition, an increase in the thickness of the SEI layer, and irreversible lithium consumption. These failure mechanisms collectively result in unacceptable electrochemical capacity loss over successive charge-discharge cycles.

[0005] Numerous approaches have been proposed to overcome the problems associated with the volume changes observed during charging of silicon-containing anodes. Fine silicon structures with cross sections less than about 150 nm, such as silicon films and silicon nanoparticles, have been reported to be more resistant to volume changes during charging and discharging compared to silicon particles in the micron size range. However, none of these are suitable for commercial-scale application without morphology modification. Nanoscale particles are difficult to manufacture and handle, and silicon films do not offer sufficient bulk capacitance.

[0006] Patent Document 1 discloses that capacity retention can be improved by using silicon particles with a high aspect ratio, i.e., the ratio of the maximum dimension to the minimum dimension of the particle. The small cross-section of such particles reduces the structural stress on the material due to volume changes during charge and discharge. However, such particles can be difficult and expensive to manufacture and can be fragile. In addition, the large surface area can lead to the formation of excessive SEI, resulting in excessive capacity loss during the first charge-discharge cycle.

[0007] It is also generally known that electroactive materials such as silicon can be deposited within the pores of porous support materials such as activated carbon materials. These composite materials offer some of the beneficial charge-discharge properties of nanoscale silicon particles while avoiding the difficulties of handling nanoparticles. Guo et al. (Non-Patent Document 2) discloses a silicon-carbon composite material in which a porous carbon substrate provides a conductive framework with silicon nanoparticles deposited uniformly distributed within the pore structure of the substrate. The composite material exhibits improved capacity retention over multiple charging cycles, but the initial capacity in mAh / g of the composite is shown to be significantly lower than that for silicon nanoparticles.

[0008] The present inventors have previously reported the development of a class of electroactive materials with composite structures in which nanoscale electroactive materials, such as silicon, are deposited within the pore network of highly porous, electrically conductive particulate materials, such as porous carbon materials. For example, U.S. Patent Nos. 5,999,929 and 5,999,933 report that the improved electrochemical performance of these materials can be attributed to the way in which the electroactive material is located within the porous material in the form of small domains with dimensions on the order of a few nanometers or less. These fine electroactive structures are believed to have lower resistance to elastic deformation and higher fracture resistance than larger electroactive structures, and therefore can be lithiated and delithiated without excessive structural stress. As a result, the electroactive materials exhibit excellent reversible capacity retention over numerous charge-discharge cycles. Second, by controlling the loading of silicon within the porous carbon skeleton so that only a portion of the pore volume is occupied by uncharged silicon, the unoccupied pore volume of the porous carbon skeleton can accommodate a significant amount of silicon expansion within it. Furthermore, by locating nanoscale electroactive material domains within small mesopores and / or micropores, as discussed above, only a small area at the surface of the electroactive material is accessible to electrolyte, thus limiting SEI formation. Further exposure during subsequent charge-discharge cycling is substantially prevented, so that the role of SEI formation as a failure mechanism leading to capacity loss is significantly reduced. This is distinct from the excessive SEI formation that characterizes the materials disclosed, for example, by Guo. A clear contrast (see above).

[0009] The materials described in Patent Documents 2 and 3 have been synthesized by chemical vapor infiltration (CVI) in different reactor systems (static, rotating, and FBR). Porous conductive particles are contacted with a flow of silicon-containing precursor (CVI), typically silane gas, at atmospheric pressure and temperatures between 400°C and 700°C until the required amount of silicon is deposited within the micropores and small mesopores. Silicon deposition is performed in a single step (single-step deposition). While performing silicon deposition in a single step is convenient, it allows little control over the length scale of the deposited silicon. The deposition of coarser silicon domains is believed to result in a decrease in reversible capacity retention due to excessive structural stress and uncontrolled SEI formation upon subsequent charge-discharge cycles.

[0010] Thus, there is a need in the art for a process that is more flexible than conventional single-step and multi-step deposition processes. A need exists for electroactive material-containing composite particles that overcome the shortcomings of the resulting composite particles. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] International Publication No. 2007 / 083155 [Patent Document 2] International Publication No. 2020 / 095067 [Patent Document 3] International Publication No. 2020 / 128495 [Non-patent literature]

[0012] [Non-Patent Document 1] Insertion Electrode Materials for Rechargeable Lithium Batteries, Winter, M. et al. in Adv. Mater. 1998, 10, No. 10 [Non-patent document 2] Journal of Materials Chemistry A, 2013, pp. 14075-14079 Summary of the Invention

[0013] In a first aspect, the present invention provides a particulate material comprising a plurality of composite particles, the composite particles comprising: (a) a porous particle framework containing micropores and / or mesopores, the total pore volume of the micropores and mesopores being less than or equal to 0.4 cm as measured by gas adsorption; 3 / g~2.2cm 3 / g, and a porous particle skeleton (b) a plurality of electroactive material domains and a plurality of modifier material domains disposed within the interior pore volume of the porous particulate framework, wherein at least a portion of the modifier material domains is located between adjacent electroactive material domains; The present invention provides a particulate material comprising:

[0014] The present invention therefore generally relates to composite particulate materials comprising a plurality of electroactive material (e.g., silicon) domains within the pore network of porous particles. The porous particles thus form the framework for the electroactive material domains. As used herein, the term "electroactive material domain" refers to a body of electroactive material, e.g., elemental silicon, having a maximum dimension determined by the dimensions of the micropores and / or mesopores of the porous particles in which they are located. Electroactive domains can therefore also be described as nanoscale electroactive domains, where the term "nanoscale" is generally understood to refer to dimensions less than 100 nm. However, due to the dimensions of the micropores and mesopores, the electroactive material domains typically have a maximum dimension in any direction that is less than, and usually significantly less than, 50 nm. The domains can take the form of, for example, regular or irregular particles or bounded layers or coated regions. The electroactive material domains can be formed by the addition of modifier materials. The modifier material domains may be present in combination with adjacent electroactive material domains, with at least a portion of the modifier material domains being located between adjacent electroactive material domains. The multiple electroactive material domains may be separate electroactive material domains. The electroactive material domains may comprise (or consist of) amorphous or crystalline electroactive material.

[0015] Several different factors contribute to the improved performance of these materials when compared to materials comprising a similar porous particle framework but without the modifier material present. The modifier material can act as a barrier that effectively prevents the individual domains of electroactive material from increasing in size as more electroactive material is deposited within the porous particle, for example, in further deposition steps. The modifier material thus limits the length scale of the deposited electroactive material, allowing further deposition of the electroactive material to form distinct electroactive material domains. Thus, composite particles are obtained that have both the desired electroactive material loading and the desired length scale of the electroactive material domains. Furthermore, the modifier material can also limit the exposed surface of the electroactive material domains. The modifier material can reduce the surface area of ​​the electroactive material, thereby minimizing SEI formation and oxidation on the electroactive material surface. Furthermore, the modifier material effectively prevents exposure of the electroactive material to the electrolyte, thereby reducing SEI formation. During extended cycling of the composite material, the structure of the composite particles can be disrupted, opening voids and channels and potentially exposing electroactive surfaces previously located within the closed pore space. This problem is exacerbated when the composite material is cycled at higher temperatures, increasing the reaction energy from repeated volume changes and chemical interactions with the electrolyte solvent and other cell components. The addition of the modifier material protects the electroactive material domain surfaces, thereby reducing the amount of degradation that can occur in such scenarios. The modifier material can also act as a conductive component; for example, a conductive carbon layer (e.g., a hydrocarbon passivation layer or a nitride passivation layer) can be used as a modifier material, acting as a conductivity enhancer located throughout the interior volume of the composite particle. This is believed to further improve the cycling efficiency and rate performance of the composite.

[0016] The porous particle framework comprises a three-dimensionally interconnected open pore network comprising micropores and / or mesopores, and optionally a small amount of macropores. In accordance with conventional IUPAC terminology, the term "micropore" is used herein to refer to pores less than 2 nm in diameter, the term "mesopore" is used herein to refer to pores between 2 nm and 50 nm in diameter, and the term "macropore" is used herein to refer to pores greater than 50 nm in diameter.

[0017] References herein to the volume of micropores, mesopores, and macropores in the porous particulate framework, as well as to the distribution of pore volume within the porous particulate framework, shall all be understood to relate to the internal pore volume of the porous particulate framework alone (i.e., in the form of the porous particle prior to deposition of the electroactive material and modifier material). References herein to the BET surface area of ​​the porous particulate framework shall also be understood to relate to the BET surface area of ​​the porous particulate framework alone.

[0018] The porous particle skeleton is 0.4 cm 3 / g~2.2cm 3 / g (i.e., total pore volume in the range of 0 nm to 50 nm). Typically, the porous particle framework contains both micropores and mesopores. However, it is not excluded that porous particle frameworks containing micropores but no mesopores, or mesopores but no micropores, can be used.

[0019] More preferably, the total volume of the micropores and mesopores in the porous particle framework is at least 0.45 cm 3 / g, or at least 0.5 cm 3 / g, at least 0.55 cm 3 / g, or at least 0.6 cm 3 / g, or at least 0.65 cm 3 / g, or at least 0.7 cm 3 / g, or at least 0.75 cm 3 / g, or at least 0.8 cm 3 / g, at least 0.85 cm 3 / g, or at least 0.9 cm 3 / g, or at least 0.95 cm 3 / g, or at least 1 cm 3 / g. The use of a highly porous scaffold may be advantageous as it allows for greater amounts of silicon to be accommodated within the pore structure.

[0020] The internal pore volume of the porous particulate skeleton is suitably limited such that the increased fragility of the porous particulate skeleton outweighs the benefit of increased pore volume to accommodate greater amounts of silicon. Preferably, the total volume of micropores and mesopores in the porous particulate skeleton is less than 2 cm. 3 / g or less, or 1.8cm 3 / g or less, or 1.6cm 3 / g or less, or 1.5cm 3 / g or less, or 1.45cm 3 / g or less, or 1.4cm 3 / g or less, or 1.35cm 3 / g or less, or 1.3cm 3 / g or less, or 1.25cm 3 / g or less, or 1.2cm 3 / g or less, or 1.1cm 3 / g or less, or 1cm 3 / g or less, or 0.95cm 3 / g or less.

[0021] Preferably, the total volume of the micropores and mesopores in the porous particle framework is less than 0.45 cm 3 / g~2.2cm 3 / g, or 0.5cm 3 / g~2cm 3 / g, or 0.55 cm 3 / g~2cm 3 / g, or 0.6cm 3 / g~1.8cm 3 / g, or 0.65 cm 3 / g~1.8cm 3 / g, or 0.7cm 3 / g~1.6cm 3 / g, or 0.7cm 3 / g~1.5cm 3 / g, or 0.7cm 3 / g~1.4cm 3 / g range.

[0022] The total volume of micropores and mesopores in the porous particle framework is also 0.55 cm 3 / g~1.4cm 3 / g, or 0.6cm 3 / g~1.4cm 3 / g, or 0.6cm 3 / g~1.3cm 3 / g, or 0.65 cm 3 / g~1.3cm 3 / g, or 0.65 cm 3 / g~1.2cm 3 / g, or 0.7cm 3 / g~1.2cm 3 / g, or 0.7cm 3 / g~1.1cm 3 / g, or 0.7cm 3 / g~1cm 3 / g, or 0.75cm 3 / g~0.95cm 3 / g.

[0023] The total volume of micropores and mesopores in the porous particle framework is also 0.4 cm 3 / g~0.75cm 3 / g, or 0.4cm 3 / g~0.7cm 3 / g, or 0.4cm 3 / g~0.65cm 3 / g, or 0.45cm 3 / g~0.75cm 3 / g, or 0.45cm 3 / g~0.7cm 3 / g, or 0.45cm 3 / g~0.65cm 3 / g, or 0.45cm 3 / g~0.6cm 3 / g.

[0024] The total volume of micropores and mesopores in the porous particle framework is also 0.6 cm 3 / g~2cm 3 / g, or 0.6cm 3 / g~1.8cm 3 / g, or 0.7cm 3 / g~1.8cm 3 / g, or 0.7cm 3 / g~1.6cm 3 / g, or 0.8cm 3 / g~1.6cm 3 / g, or 0.8cm 3 / g~1.5cm 3 / g, or 0.8cm 3 / g~1.4cm 3 / g, or 0.9 cm 3 / g~1.5cm 3 / g, or 0.9 cm 3 / g~1.4cm 3 / g or 1cm 3 / g~1.4cm 3 / g.

[0025] "PD n The generic term "pore size" as used herein refers to the nth percentile pore size on a volume basis relative to the total volume of micropores and mesopores. For example, "PD" as used herein refers to the nth percentile pore size on a volume basis relative to the total volume of micropores and mesopores. 50 The term "pore size" refers to the pore size below which 50% of the total micropore and mesopore volume is found.

[0026] PD of porous particle framework 50 The pore size may be 30 nm or less, preferably 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1.5 nm or less. 50The term "pore size" refers to the median pore size on a volume basis relative to the total volume of micropores and mesopores. Thus, at least 50% of the total volume of micropores and mesopores is preferably in the form of pores with a diameter of less than 30 nm.

[0027] PD of porous particle framework 30 The pore size may be 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1 nm or less.

[0028] PD of porous particle framework 90 The pore size may be 35 nm or less, or 30 nm or less, or 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less. Preferably, the PD of the porous particle skeleton 90 The pore size is at least 2.5 nm, or at least 3 nm, or at least 3.5 nm, or at least 4 nm. For example, the PD of the porous particle skeleton 90 The pore diameter is preferably in the range of 2.5 nm to 20 nm, or 3 nm to 15 nm, or 3.5 nm to 10 nm, or 4 nm to 8 nm.

[0029] PD of porous particle framework 10 The pore size may be 10 nm or less, or 9 nm or less, or 8 nm or less, or 7 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1.5 nm or less, or 1 nm or less. Preferably, the PD of the porous particle skeleton 10 The pore size is at least 0.3 nm, or at least 0.4 nm, or at least 0.5 nm. For example, the PD of the porous particle skeleton 10The pore diameter is preferably in the range of 0.3 nm to 10 nm, or 0.3 nm to 5 nm, or 0.3 nm to 1 nm, or 0.4 nm to 1 nm, or 0.5 nm to 1 nm.

[0030] To avoid any misunderstanding, PD n For the purposes of determining the value, any macropore volume (pore diameters greater than 50 nm) is not taken into account.

[0031] Preferably, the volume of the micropores in the porous particle framework is at least 0.25 cm 3 / g, or at least 0.3 cm 3 / g, at least 0.4 cm 3 / g, or at least 0.5 cm 3 Preferably, the volume of the micropores in the porous particle framework is 1.7 cm 3 / g or less, or 1.5cm 3 / g or less, or 1.2cm 3 / g. The volume of the micropores in the porous particle framework is 0.3 cm 3 / g~1.7cm 3 / g, or 0.3 cm 3 / g~1.5cm 3 / g, or 0.3 cm 3 / g~1.2cm 3 The volume of the micropores in the porous particle framework may be in the range of 0.4 cm 3 / g~1.7cm 3 / g, or 0.5cm 3 / g~1.7cm 3 The volume of the micropores in the porous particle framework may be in the range of 0.4 cm 3 / g~1.5cm 3 / g, or 0.5cm 3 / g~1.2cm 3 / g. While a certain amount of micropore-sized voids in the porous particle framework helps achieve deposition of small-sized electroactive material domains within the pores, too high a micropore volume may excessively restrict infiltration of the porous particle framework by precursors of the electroactive and modifier domains.

[0032] The volume ratio of micropores to mesopores in the porous particle framework can in principle be in the range of 100:0 to 0:100. Preferably, the volume ratio of micropores to mesopores is 90:10 to 30:70, or 85:15 to 40:60, or 80:20 to 50:50, or 70:30 to 55:45.

[0033] The total volume of micropores and mesopores, as well as the pore size distribution of micropores and mesopores, were determined at 77 K using quenched solid-state density functional theory (QSDFT) according to the standard methodology specified in ISO 15901-2 and ISO 15901-3. -6 The pore volume and pore size distribution are determined using nitrogen gas adsorption up to a relative pressure of p / p0. Nitrogen gas adsorption is a technique for characterizing the porosity and pore size distribution of a material by condensing a gas in the pores of a solid. As the pressure is increased, the gas initially condenses in the pores with the smallest diameters until the saturation point is reached, at which point all pores are filled with liquid. The nitrogen gas pressure is then reduced in stages, causing the liquid to evaporate from the system. The pore volume and pore size distribution can be determined by analyzing the adsorption and desorption isotherms and the hysteresis between them. Suitable devices for measuring the pore volume and pore size distribution by nitrogen gas adsorption include the TriStar II Porosity Analyzer and the TriStar II Porosity Analyzer available from Micromeritics Instrument Corporation, USA. Plus Porosity Analyzer, as well as the Autosorb IQ Porosity Analyzer available from Quantachrome Instruments.

[0034] Nitrogen gas adsorption is effective for measuring the pore volume and pore size distribution of pores with diameters up to 50 nm, but becomes less reliable for pores with much larger diameters. Therefore, for the purposes of this invention, nitrogen adsorption is used to determine the pore volume and pore size distribution of only pores with diameters up to 50 nm or less (i.e., only micropores and mesopores). Similarly, PD 50 The value of is determined relative to the total volume of micropores and mesopores only.

[0035] Given the limitations of available analytical techniques, it is not possible to measure the pore volume and pore size distribution across the entire range of micropores, mesopores, and macropores using a single technique. When a porous particle or porous particle framework contains macropores, the volume of pores having diameters greater than 50 nm up to 100 nm can be measured by mercury intrusion porosimetry, preferably at a depth of 0.3 cm. 3 / g or less, or 0.2cm 3 / g or less, or 0.1cm 3 / g or less, or 0.05cm 3 / g or less. Although a small proportion of macropores can be useful to facilitate electrolyte access within the pore network, the benefits of the present invention are substantially achieved by containing silicon in the micropores and smaller mesopores.

[0036] Any pore volume measured by mercury porosimetry at pore diameters of 50 nm or less is disregarded (as discussed above, nitrogen adsorption is used to characterize mesopores and micropores). Pore volume measured by mercury porosimetry above 100 nm is assumed to be interparticle porosity for purposes of this invention, and this pore volume is also disregarded.

[0037] Mercury intrusion porosimetry is a technique for characterizing the porosity and pore size distribution of a material by applying various levels of pressure to a sample of the material immersed in mercury. The pressure required to force mercury into the pores of the sample is inversely proportional to the pore size. Mercury intrusion values ​​reported herein were obtained according to ASTM UOP578-11, assuming a surface tension γ of 480 mN / m and a contact angle φ of 140° for mercury at room temperature. The density of mercury at room temperature is 13.5462 g / cm. 3 Many high-precision mercury intrusion instruments are commercially available, such as the AutoPore IV series of automated mercury intrusion porosimetry instruments available from Micromeritics Instrument Corporation, USA. For a complete review of mercury intrusion techniques, see P.A. Webb and C. Orr. “Analytical Methods in Fine Particle Technology, 1997, Micromeritics Instrument Corporation" (ISBN 0-9656783-0).

[0038] It will be understood that intrusion techniques such as gas adsorption and mercury porosimetry are only effective for determining the pore volume of pores accessible to nitrogen or mercury from the exterior of the porous particle. The porosity values ​​specified herein should be understood to refer to the volume of open pores, i.e., pores accessible to fluids from the exterior of the porous particle. Completely enclosed pores that cannot be identified by nitrogen adsorption or mercury porosimetry shall not be considered in determining the porosity values ​​herein. Similarly, any pore volume located within pores small enough to be below the detection limit by nitrogen adsorption shall not be considered.

[0039] The pore size distribution of the porous particulate scaffold may be unimodal, bimodal, or multimodal. As used herein, the term "pore size distribution" refers to the distribution of pore sizes relative to the cumulative total internal pore volume of the porous particulate scaffold. Bimodal or multimodal pore size distributions may be preferred, as the proximity of micropores to larger diameter pores provides the advantage of efficient ion transport through the porous network to the silicon.

[0040] The porous particle framework is preferably at least 100 mm 2 / g, or at least 500m 2 / g, or at least 750m 2 / g, or at least 1000m 2 / g, or at least 1250m 2 / g, or at least 1500m 2 / g. As used herein, the term "BET surface area" should be taken to refer to the surface area per unit mass calculated from measurements of the physical adsorption of gas molecules on a solid surface using the Brunauer-Emmett-Teller theory and in accordance with ISO 9277. Preferably, the BET surface area of ​​the porous particle framework is greater than 4000 m 2 / g or less, or 3500m 2 / g or less, or 3250m 2 / g or less, or 3000m 2 / g or less, or 2500m 2 / g or less, or 2000m 2 For example, the porous particle skeleton is 100 m 2 / g~4000 m 2 / g, or 500m 2 / g~4000m 2 / g, or 750m 2 / g~3500m 2 / g, or 1000m 2 / g~3250m 2 / g, 1000m 2 / g~3000m 2 / g, or 1000m 2 / g~2500m 2 / g, or 1000m 2 / g~2000m 2 / g.

[0041] The porous particle skeleton is preferably electrically conductive. The electrically conductive porous particle skeleton comprises or consists of an electrically conductive carbon material. The electrically conductive porous carbon particle skeleton preferably comprises at least 80% by weight of carbon, more preferably at least 90% by weight of carbon, more preferably at least 95% by weight of carbon, optionally at least 98% by weight or at least 99% by weight of carbon. The carbon may be crystalline carbon or amorphous carbon, or a mixture of amorphous carbon and crystalline carbon. The carbon may be either carbon or soft carbon.

[0042] As used herein, the term "hard carbon" refers to a carbon atom in which the carbon atoms are primarily distributed in nanoscale polyaromatic domains. 2 It refers to a disordered carbon matrix that is in a hybridized state (three-way bonding). The polyaromatic domains are cross-linked by chemical bonds, such as COC bonds. Because the polyaromatic domains are chemically cross-linked, the hard carbon cannot be converted to graphite at high temperatures. The high G band (approximately 1600 cm) in the Raman spectrum -1 ), hard carbons have graphite-like properties. However, the high D band (approximately 1350 cm) in the Raman spectrum -1 ), carbon is not completely graphite-like.

[0043] The term "soft carbon" as used herein also refers to carbon atoms that are primarily dispersed in polyaromatic domains with dimensions in the range of 5 nm to 200 nm. 2 It refers to a disordered carbon matrix that adopts a hybridized state (three-way bonding). In contrast to hard carbon, the polyaromatic domains in soft carbon are not cross-linked by chemical bonds but are held together by intermolecular forces. That is, at high temperatures, soft carbon can be graphitized. The porous carbon skeleton preferably has at least 50% sp as measured by XPS. 2 For example, the porous carbon skeleton preferably contains 50% to 98% sp 2 Hybrid carbon, 55% to 95% sp 2 Hybrid carbon, 60%-90% sp 2 Hybrid carbon, or 70% to 85% sp 2 It may contain hybridized carbon.

[0044] A variety of different materials can be used to prepare porous particles suitable for forming porous particle skeletons through pyrolysis. Examples of organic materials that can be used include plant biomass, including lignocellulosic materials (such as coconut shells, rice husks, and wood), and fossil carbon sources such as coal. Examples of resins and polymeric materials that form porous carbon particles upon pyrolysis include phenolic resins, novolac resins, pitch, melamine, polyacrylates, polystyrene, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and various copolymers containing monomer units of acrylates, styrene, α-olefins, vinylpyrrolidone, and other ethylenically unsaturated monomers. Depending on the starting materials and pyrolysis process conditions, a variety of different carbon materials are available in the art. Porous carbon particles with a variety of different specifications are available from suppliers.

[0045] To increase the mesopore and micropore volume, the porous carbon particles can be subjected to a chemical or gas activation process. Suitable activation processes include contacting pyrolyzed carbon with one or more of oxygen, steam, CO, CO2, and KOH at temperatures ranging from 600°C to 1000°C.

[0046] Mesopores can also be obtained by known templating processes using extractable pore-forming agents such as MgO and other colloidal or polymeric templates that can be removed by thermal or chemical means after pyrolysis or activation.

[0047] Alternatives to carbon-based particle skeletons include titanium nitride (TiN), titanium carbide (TiC), silicon carbide (SiC), and nickel oxide (NiO x ), titanium silicon nitride (TiSiN), nickel nitride (NiN), molybdenum nitride (MoN), titanium oxynitride (TiO x N 1-x), silicon oxycarbide (SiOC), boron nitride (BN), or vanadium nitride (VN). Preferably, the porous particle skeleton comprises titanium nitride (TiN), silicon oxycarbide (SiOC), or boron nitride (BN). Further alternatives to carbon-based particle skeletons include metal oxides, such as those of formula TiO x The porous particle framework includes an oxide of titanium having the formula: where x has a value greater than 1 and less than 2.

[0048] The porous particle scaffold may be irregular or spheroidal in shape.

[0049] The multiple electroactive material domains may each comprise the same electroactive material, or different electroactive material domains may comprise different electroactive materials. Preferably, the electroactive material domains comprise an electroactive material selected from elemental silicon, elemental tin, elemental germanium, elemental aluminum, and mixtures and alloys thereof. For example, some electroactive material domains may comprise (or consist of) elemental silicon, while other electroactive material domains may comprise (or consist of) elemental germanium. A preferred electroactive material is silicon. Preferably, at least some of the electroactive material domains comprise or consist of elemental silicon. More preferably, all of the electroactive material domains comprise or consist of elemental silicon.

[0050] As used herein, a "modifier material domain" refers to a material domain having a chemical composition distinct from that of an electroactive material domain. At least a portion of the modifier material domain is located between adjacent electroactive material domains. The requirement that "at least a portion of the modifier material domain is located between adjacent electroactive material domains" should be interpreted to mean that the pore space of the porous particle framework is successively occupied by an electroactive material domain, then a modifier material domain, and then a further electroactive material domain. Thus, the electroactive material does not form an extended network throughout the pore space, but is interrupted by the modifier material domain. Thus, within a single pore space, the order: [Electroactive material domain(s)] ↓ [Modifier Material Domain(s)] ↓ [Electroactive material domain(s)] There is an assembly of material domains according to

[0051] This sequence of materials is generally achieved by sequentially depositing an electroactive material and a modifier material within the pores of a porous particulate framework, as discussed in more detail below, and the sequence can be extended, if desired, by further electroactive material domains and / or further modifier material domains.

[0052] Modifier material domains located between adjacent electroactive material domains can act as a barrier separating the electroactive material domains and limit the length scale of consecutive electroactive material domains within the composite particle. Modifier material domains located between adjacent electroactive material domains can act as a barrier separating the electroactive material domains. Modifier material domains located between adjacent electroactive material domains can function to limit the length scale of consecutive electroactive material domains within the composite particle.

[0053] The electroactive material domain and the modifier material domain are separate domains, which may have a distinct boundary between the two, or there may be a compositional gradient between the electroactive domain and the modifier material domain. The modifier material domain may be a coating (e.g., a film) on at least some or all of the surfaces of the electroactive material domain. The modifier material domain may be chemically bonded (e.g., covalently, ionically or metallically) to the electroactive material domain. For example, the modifier material domain may include a passivation layer on the surface of the electroactive material domain, or may include an alloy of the electroactive material on the surface of the electroactive material domain, or may include a doped electroactive material on the surface of the electroactive material domain. Alternatively, the modifier material domain may not be chemically bonded to the electroactive material domain. For example, the modifier material can include or consist of a solid state electrolyte or an inert filler.

[0054] The modifier material domain can include one or more of carbon, nitrogen and / or oxygen.

[0055] The modifier material domain can be a passivation layer.

[0056] The modifier material domain may be an oxide passivation layer. One type of modifier material is, for example, a native oxide passivation layer formed by exposing the surface of the electroactive material domain to air or another oxygen-containing gas. When the electroactive material domain contains silicon, the modifier material domain may include silicon oxide of the formula SiO x (where 0 < x ≦ 2). The silicon oxide is preferably amorphous silicon oxide.

[0057] The modifier material domain may be a nitride passivation layer. Another type of modifier material is, for example, a nitride passivation layer formed by exposing the surface of the electroactive material domain to ammonia or another nitrogen-containing molecule. When the electroactive material domain contains silicon, the modifier material domain may have the formula SiN x(where 0 < x ≤ 4 / 3) may include silicon nitride. The silicon nitride is preferably amorphous silicon nitride. The nitride modifier material is more preferable than the oxide modifier material. The stoichiometric nitride (e.g., SiN x (where 0 < x ≤ 4 / 3)) is conductive, so the nitride modifier domain functions as a conductive network that enables faster charging and discharging of the electroactive material. The nitride modifier material domain may also be considered to improve the capacity retention rate. Phosphine may also be used as a passivating agent as a phosphorus analog of ammonia.

[0058] The modifier material domain may be an oxynitride passivation layer. Another type of modifier material is, for example, an oxynitride passivation layer formed by exposing the surface of the electroactive material domain to ammonia (or another nitrogen-containing molecule) and oxygen gas. When the electroactive material domain contains silicon, the modifier material domain may contain silicon oxynitride of the formula SiO x N y (where 0 < x < 2, 0 < y < 4 / 3, and 0 < (2x + 3y) ≤ 4). The silicon nitride is preferably amorphous silicon oxynitride.

[0059] The modifier material domain may be a carbide passivation layer. Another type of modifier material is a carbide passivation layer. When the electroactive material domain contains silicon, the modifier material domain may contain silicon carbide of the formula SiC x (where 0 < x ≤ 1). The silicon carbide is preferably amorphous silicon carbide. The silicon carbide layer may be formed by contacting the surface of the electroactive material domain with a carbon-containing precursor, such as methane or ethylene, at an elevated temperature.

[0060] Another type of modifier material is a passivation layer that includes an organic moiety covalently bonded to at least a portion of the surface of the electroactive material domain. For example, the modifier material domain may include a carbon-containing organic moiety covalently bonded to the surface of the electroactive material domain. For example, the modifier material dom The in may comprise a hydrocarbyl covalently bonded to the surface of the electroactive material domain.

[0061] Suitable passivating agents for forming a passivating layer containing an organic moiety include compounds containing an alkene, alkyne, or carbonyl functionality, more preferably a terminal alkene, terminal alkyne, aldehyde, or ketone group.

[0062] Covalently bonded organic modifier material domains can be formed by inserting organic compounds into M—H groups (where M represents an atom of the electroactive material) on the surface of the electroactive material to form a covalently passivated surface that is resistant to oxidation by air. When silicon is the electroactive material, the passivation reaction between the silicon surface and the passivating agent can be understood as a form of hydrosilylation, as shown schematically below: [ka]

[0063] Because hydride terminations can decompose to produce hydrogen gas, which can be detrimental to the electrode topography, it is advantageous to replace the hydride terminations at the surface of the electroactive material domains with covalently bonded organic modifier material domains, such as carbon-containing organic moieties. Additionally, Si-C bonds are believed to improve electrical conductivity.

[0064] Suitable organic compounds that can be used to form modifier material domains through passivation of the electroactive material domain surfaces include compounds that contain an alkene, alkyne, or carbonyl functional group, more preferably a terminal alkene, terminal alkyne, or aldehyde group. For example, modifier material domains may be formed by passivation of the electroactive material domain surfaces with one or more compounds of the following formula:

[0065] Preferred passivators include those having the following formula: (i)R 1 -CH=CH-R 1 , (ii)R1 -C≡CR 1 , and (iii) O=CR 1 R 1 (In the formula, each R 1 independently represent H or an unsubstituted or substituted aliphatic or aromatic hydrocarbyl group having 1 to 20 carbon atoms, or two R 1 The group includes one or more compounds of the formula (which may form an unsubstituted or substituted ring structure containing 3 to 8 carbon atoms in the ring).

[0066] The modifier material may be a hydrocarbyl covalently bonded to the surface of at least a portion of the electroactive material domain. The modifier material may be a C covalently bonded to the surface of at least a portion of the electroactive material domain. 2~22 The modifier material may be a saturated or unsaturated C group covalently bonded to the surface of at least a portion of the electroactive material domains. 2~22 The modifier material may be a linear or branched C group covalently bonded to the surface of at least a portion of the electroactive material domains. 2~22 The modifier material may be a mono- or poly-cyclic C group covalently bonded to the surface of at least a portion of the electroactive material domains. 2~22 The modifier material may be a C hydrocarbyl. The modifier material may be a C covalently bonded to the surface of at least a portion of the electroactive material domains. 2~22 Alkyl, C 2~22 Alkenyl, C 2~22 Alkynyl, C 3~22 Cycloalkyl, C 3~22 Cycloalkenyl, C 3~22 Cycloalkynyl or C 6~22 The modifier material may be covalently bonded to the surface of at least a portion of the electroactive material domains. [ka] It will be understood that the bond crossed by the dotted line is directed to an atom on the surface of the electroactive material domain. For example, if the electroactive material is silicon, the bond crossed by the dotted line is directed to Si.

[0067] Particularly preferred passivators include those having the following formula: (i) CH2=CH-R 1 , and (ii) HC≡CR 1 (In the formula, R 1 is as defined above). Preferably, R 1 is non-substituted.

[0068] Specific examples of suitable organic compounds that can be used to form modifier material domains through passivation of the electroactive material domain surfaces include ethylene, propylene, 1-butene, butadiene, 1-pentene, 1,4-pentadiene, 1-hexene, 1-octene, styrene, divinylbenzene, acetylene, phenylacetylene, norbornene, norbornadiene, and bicyclo[2.2.2]oct-2-ene. Mixtures of different passivating agents can also be used.

[0069] Further examples of organic compounds that can be used to form modifier material domains through passivation of the electroactive material domain surface include compounds containing an active hydrogen atom bonded to oxygen, nitrogen, sulfur, or phosphorus. For example, the passivator can be an alcohol, amine, thiol, or phosphine. It is understood that reaction of an -XH group with a hydride group at the electroactive material surface results in elimination of H and formation of a direct bond between X and the electroactive material surface.

[0070] Suitable passivators in this category include those of the following formula: (iv) HX-R 2 , and (v) HX-C(O)-R 1 (wherein X is O, S, NR1 or PR 1 indicates each R 1 are independently defined above and Yes, R 2 represents an unsubstituted or substituted aliphatic or aromatic hydrocarbyl group having 1 to 20 carbon atoms, or R 1 and R 2 together form an unsubstituted or substituted ring structure containing 3 to 8 carbon atoms in the ring.

[0071] Preferably, X represents O or NH. Particularly preferably, X represents NH.

[0072] Preferably, R 2 represents an optionally substituted aliphatic or aromatic group having 2 to 10 carbon atoms. Amine groups may also be incorporated into 4- to 10-membered aliphatic or aromatic ring structures, such as in pyrrolidine, pyrrole, imidazole, piperazine, indole, or purine.

[0073] As a further alternative, the modifier material domains may comprise pyrolytic carbon materials, which may be formed by CVI using appropriate carbon-containing precursors, as discussed in more detail below. The use of pyrolytic carbon materials is advantageous in that it significantly reduces the surface area of ​​the composite particles, which is believed to improve cycle life and preserve capacity.

[0074] As a further alternative, the modifier material domains may be conductive metals or metal alloys. Conductive metal or metal alloy domains can be formed by CVI using suitable metal-containing precursors, as discussed in more detail below. Examples of suitable conductive metals include silver, gold, copper, and titanium.

[0075] As a further alternative, the modifier material domain may include an electroactive material comprising a dopant selected from the group consisting of boron, aluminum, gallium, indium, phosphorus, arsenic, antimony, and bismuth. The dopant is preferably boron or phosphorus. The electroactive material may be the same electroactive material in the electroactive material domain or may be different. The electroactive material may be selected from the group consisting of elemental silicon, elemental tin, elemental germanium, elemental aluminum, and mixtures and alloys thereof. A preferred electroactive material is silicon.

[0076] As a further alternative, the modifier material domain may comprise or consist of a solid-state electrolyte, which may be an organic solid electrolyte or an inorganic solid electrolyte.

[0077] Examples of organic solid electrolytes include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, and polymers containing ionically dissociable groups.

[0078] Examples of inorganic solid electrolytes include nitrides, halides and sulfides of lithium salts, such as Li5NI2, Li3N, LiI, LiSiO4, Li2SiS3, Li4SiO4, LiOH and Li3PO4.

[0079] As a further alternative, the modifier material domain may include or consist of an inert filler.

[0080] Preferably, the modifier material is oxygen-free. The use of oxygen-free modifier materials is believed to contribute to providing composite particles with a low total oxygen content, which is believed to reduce first cycle losses, improve electronic conductivity, improve cycle life, and maintain capacity. Examples of oxygen-free modifier materials include nitride passivation layers, carbide passivation layers, and the like. These include passivation layers, hydrocarbyls covalently bonded to the surface of electroactive material domains, pyrolytic carbon materials, conductive metals or metal alloys, electroactive materials including dopants, solid state electrolytes, and inert fillers.

[0081] In a preferred embodiment, the modifier material comprises a hydrocarbyl (e.g., C) covalently bonded to the surface of at least a portion of the electroactive material domains. 2~22 Hydrocarbyl), or nitride passivation layers as described herein. These modifier materials are believed to provide lower total oxygen content, improve electrical conductivity, and reduce chemical reactivity of the electroactive material domains.

[0082] The composite particles may optionally further include outer modifier material domains located between the outermost electroactive material domain and the exterior of the composite particle. These modifier material domains form a barrier between the electroactive material and the exterior of the composite particle, thereby inhibiting contact between the outermost electroactive material domain and the electrolyte, which would otherwise tend to result in SEI formation. The outer modifier material domains may be formed from any of the modifier materials described herein. A preferred modifier material for the outer modifier material domains is a pyrolytic carbon material. Another preferred modifier material for the outer modifier material domains is a native oxide of the electroactive material.

[0083] In a preferred embodiment, the particulate material of the present invention comprises a plurality of elemental silicon domains (as electroactive domains) and a plurality of modifier material domains disposed within the interior pore volume of a porous particle framework, the modifier material domains comprising organic moieties located between adjacent elemental silicon domains and comprising a passivation layer covalently bonded to the surface of at least a portion of the elemental silicon domains. The composite particle may further comprise an outer modifier material domain that is a silicon oxide domain.

[0084] In a further preferred embodiment, the particulate material of the present invention comprises a plurality of elemental silicon domains (as electroactive domains) and a plurality of pyrolytic carbon domains disposed within the interior pore volume of a porous particle framework, at least some of the pyrolytic carbon domains being located between adjacent elemental silicon domains. The composite particle may further comprise an outer modifier material domain which is a silicon oxide domain.

[0085] In a further preferred embodiment, the particulate material of the present invention comprises a plurality of elemental silicon domains (as electroactive domains) and a plurality of metal or metal alloy domains disposed within the interior pore volume of the porous particle framework, at least some of the metal or metal alloy domains being located between adjacent elemental silicon domains. The composite particle may further comprise an outer modifier material domain which is a silicon oxide domain.

[0086] A range of different electroactive material loadings in the composite particles may be used in the present invention. For example, the amount of electroactive material in the composite particles may range from 5% to 85% by weight, based on the total weight of the composite particle. Preferably, the amount of electroactive material in the composite particles is 10% to 85% by weight, or 15% to 85% by weight, or 20% to 80% by weight, or 25% to 80% by weight, or 30% to 75% by weight, or 35% to 75% by weight, or 40% to 70% by weight, or 45% to 65% by weight, based on the total weight of the composite particle.

[0087] The composite particles can comprise 40% to 70% by weight, or 45% to 70% by weight, or 48% to 70% by weight, or 50% to 70% by weight, or 40% to 65% by weight, or 45% to 65% by weight, or 48% to 65% by weight, or 50% to 65% by weight, or 40% to 60% by weight, or 45% to 60% by weight, or 48% to 60% by weight, or 50% to 60% by weight of the electroactive material, based on the total mass of the composite particles.

[0088] Preferably, the composite particles comprise 10% to 85% by weight, or 15% to 85% by weight, or 20% to 80% by weight, or 25% to 80% by weight, or 30% to 75% by weight, or 35% to 75% by weight, or 40% to 70% by weight, or 45% to 65% by weight of silicon, based on the total mass of the composite particles.

[0089] The composite particles can contain 40% to 70% by weight, or 45% to 70% by weight, or 48% to 70% by weight, or 50% to 70% by weight, or 40% to 65% by weight, or 45% to 65% by weight, or 48% to 65% by weight, or 50% to 65% by weight, or 40% to 60% by weight, or 45% to 60% by weight, or 48% to 60% by weight, or 50% to 60% by weight of silicon, based on the total mass of the composite particles.

[0090] The amount of electroactive material (e.g., silicon) in the composite particles can be selected so that at least 25% and up to 90% or more of the internal pore volume of the porous particle skeleton is occupied by the electroactive material. For example, the electroactive material (e.g., silicon) may occupy 25% to 80%, or 25% to 60%, or 25% to 55%, or 30% to 50%, or 53% to 55%, or 40% to 60%, or 25% to 45%, or 25% to 40% of the internal pore volume of the porous particle skeleton. Within these preferred ranges, the pore volume of the porous particle skeleton is effective to accommodate expansion of the electroactive material (e.g., silicon) during charge and discharge, while avoiding excess pore volume that does not contribute to the volumetric capacity of the particle. However, the amount of electroactive material is also not so great as to prevent effective lithiation due to inadequate metal ion diffusion rates or inadequate expansion volume resulting in mechanical resistance to lithiation.

[0091] When the electroactive material is silicon, the amount of silicon in the composite particles is determined such that the mass ratio of silicon to porous particle skeleton is [0.5 × P 1 ~1.9×P 1 ]:1, where P1 is cm 3 The total pore volume of the porous particle framework is a dimensionless quantity, having a measure of the total pore volume of the micropores and mesopores in the porous particle framework, expressed as 1.2 cm / g (e.g., when the porous particle or porous particle framework is 1.2 cm). 3 / g, then P 1 =1.2). This relationship takes into account the density of the silicon and the pore volume of the porous particle framework, and defines the weight ratio of silicon at which the pore volume is approximately 20% to 82% occupied.

[0092] The amount of electroactive material (e.g., silicon) in the composite particles can be determined by elemental analysis. Elemental analysis can be used to determine the composition of the porous particles that form only the porous particle skeleton, as well as the composition of the electroactive material-containing composite particles. For example, determining the weight percentage of carbon in the porous carbon particles alone takes into account the possibility that the porous carbon particles contain trace amounts of heteroatoms. Both measurements together allow for a reliable determination of the weight percentage of the electroactive material (e.g., silicon) relative to the porous carbon particles.

[0093] The silicon content is preferably determined by ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy). ICP-OES analyzers available from ThermoFisher Scientific Many ICP-OES instruments are commercially available, such as the iCAP™ 7000 series from ICP-OES. The carbon content (and optionally hydrogen, nitrogen, and oxygen content) in the composite particles and the porous carbon particles alone is preferably determined by IR absorption. A suitable instrument for determining carbon, hydrogen, nitrogen, and oxygen content is the TruSpec™ Micro elemental analyzer available from Leco Corporation.

[0094] At least 85% by weight of the electroactive material mass in the composite particles can be located within the interior pore volume of the porous particle framework. Preferably, there is no or no electroactive material on the exterior surface of the composite particles. At least 90 wt. % of the mass of the electroactive material (e.g., silicon) in the composite particles is located within the internal pore volume of the porous particle framework, more preferably at least 95 wt. %, and even more preferably at least 98 wt. % of the electroactive material (e.g., silicon) is located within the internal pore volume of the porous particle framework, so that very little electroactive material (e.g., silicon) is located within the internal pore volume of the porous particle framework. The kinetics of the CVI process ensure that preferential deposition of the electroactive material (e.g., silicon) occurs on the internal surfaces of the porous particles.

[0095] The composite particles preferably have a low total oxygen content. Oxygen may be present in the composite particles, for example, as part of the porous particle skeleton or as an oxide layer on any exposed silicon surfaces. Preferably, the total oxygen content of the composite particles is less than 15 wt%, more preferably less than 10 wt%, more preferably less than 5 wt%, for example, less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, based on the total mass of the composite particles. Preferably, the total oxygen content of the composite particles is less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, based on the total mass of the composite particles.

[0096] The composite particles may comprise a ratio of total oxygen content to silicon content relative to the total mass of the composite particles of 0.1:1 or less.

[0097] The composite particles preferably have a low total chlorine content. Chlorine may be present in the composite particles, for example, as part of a by-product of electroactive material deposition. Preferably, the total chlorine content of the composite particles is less than 100 ppm, or less than 90 ppm, or less than 80 ppm, or less than 70 ppm, based on the total mass of the composite particles. Without being bound by theory, it is believed that chlorine is an impurity in the composite particles that is detrimental to cell performance.

[0098] The composite particles preferably have a low total content of transition metals and / or alkali metals, for example, the total content of transition metals and alkali metals in the composite particles may be less than 0.5 wt. % based on the total weight of the composite particles.

[0099] Optionally, the composite particle comprises 0.0001% to 0.5% by weight, such as 0.001% to 0.1% by weight, of zirconium relative to the total mass of the composite particle.

[0100] The composite particles preferably have a D in the range of 0.5 μm to 30 μm. 50 The composite particles at the end of the CVI process have a particle diameter of D 50 If the particle size is greater than 30 μm, it is preferably milled, e.g., by milling, to a D of 30 μm or less before use in electrode manufacture. 50 Reduce the size of the composite particles to a particle size of 30 μm or less. 50 The composite particles with this particle size have excellent dispersibility in slurries, structural robustness, and high capacity retention over repeated charge-discharge cycles, making them suitable for forming dense electrode layers with uniform thickness in the conventional thickness range of 20 μm to 50 μm.

[0101] Optionally, D of the composite particle 50 The particle size may be at least 1 μm, or at least 2 μm, or at least 3 μm, or at least 4 μm, or at least 5 μm. 50 The particle size may be 20 μm or less, or 18 μm or less, or 16 μm or less, or 14 μm or less, or 12 μm or less, or 10 μm or less, or 8 μm or less.

[0102] For example, the composite particles may have a D in the range of 1 μm to 25 μm, or 1 μm to 20 μm, or 1 μm to 18 μm, or 1 μm to 16 μm, or 2 μm to 16 μm, or 2 μm to 14 μm, or 2 μm to 12 μm, or 2 μm to 10 μm, or 2 μm to 8 μm. 50 It can have a particle size.

[0103] D of composite particles 10 The particle size is preferably at least 0.5 μm, or at least 0. 8 μm, or at least 1 μm. D 10Maintaining particle size above 0.5 μm reduces the likelihood of undesired agglomeration of submicron-sized particles, improving dispersibility of the particulate material and improving volume retention.

[0104] D of composite particles 90 The particle size is preferably 50 μm or less, or 40 μm or less, or 30 μm or less, or 25 μm or less, or 20 μm or less, or 15 μm or less. The presence of very large particles leads to uneven particle packing in the electrode active layer, which hinders the formation of a dense electrode layer, particularly an electrode layer having a thickness in the range of 20 μm to 50 μm. Therefore, D 90 Preferably the particle size is up to 40 μm, and even smaller is more preferred.

[0105] The composite particles preferably have a narrow particle size distribution span. For example, the particle size distribution span (D 90 -D 10 ) / D 50 (defined as) is preferably 5 or less, more preferably 4 or less, more preferably 3 or less, more preferably 2 or less, and most preferably 1.5 or less. By maintaining a narrow particle size distribution span, efficient packing of particles into a dense electrode layer can be more easily achieved.

[0106] For the avoidance of doubt, the term "particle size" as used herein refers to the equivalent spherical diameter (esd), i.e., the diameter of a sphere having the same volume as a particle, where the volume of the particle is understood to include the volume of the pores within the particle. 50 " and "D 50 The term "particle size" refers to the median particle size on a volume basis, i.e., the diameter below which 50% by volume of the particle population lies. 10 " and "D 10 The term "particle size" refers to the 10th percentile median particle diameter on a volume basis, i.e., the diameter below which 10% by volume of the particle population lies. 90 " and "D 90The term "particle size" refers to the 90th percentile median particle size on a volume basis, i.e., the diameter below which 90% of the particle population by volume lies.

[0107] Particle size and size distribution can be determined by standard laser diffraction techniques according to ISO 13320:2009. Laser diffraction is based on the principle that particles scatter light at angles that vary depending on the size of the particle, and that a collection of particles produces a scattered light pattern defined by intensity and angle that can be correlated to particle size distribution. Many laser diffraction instruments are commercially available for quickly and reliably determining particle size distribution. Unless otherwise specified, particle size distribution measurements defined or reported herein are based on measurements made by Malvern Instruments™. The measurements were performed using a conventional Malvern Mastersizer™ 3000 particle size analyzer manufactured by Aerospace Engineering, Inc. The Malvern Mastersizer™ 3000 particle size analyzer operates by projecting a helium-neon gas laser beam through a transparent cell containing particles of interest suspended in an aqueous solution. Light striking the particles is scattered at angles inversely proportional to the particle diameter, and a photodetector array measures the light intensity at several predetermined angles. The intensities measured at various angles are processed by a computer using standard theoretical principles to determine the particle size distribution. Laser diffraction values ​​as reported herein are obtained using a wet dispersion of particles in 2-propanol with 5% by volume of the surfactant SPAN™-40 (sorbitan monopalmitate). The refractive index of the particles is taken to be 2.68 for porous particles and 3.50 for composite particles, and the refractive index of the dispersant is taken to be 1.378. The Mie scattering model is used to calculate the particle size distribution.

[0108] The composite particles are preferably 0.35 cm 3 / g or less, or 0.25cm 3 / g or less, or 0.15cm 3 / g or less, or 0.1cm 3 / g or less, or 0.05cm 3 / g or less, or 0.03cm 3 / g or less, or 0.02cm 3 and a total volume of micropores and / or mesopores, as measured by nitrogen gas adsorption as described herein, of less than or equal to 1000 μg / g. Preferably, the total volume of the micropores and / or mesopores in the composite particles is 20% by volume or less, more preferably 15% by volume or less, or 10% by volume or less, or 5% by volume or less, of the total volume of the micropores and / or mesopores in the porous particle framework. A lower total volume of micropores and / or mesopores in the composite particles reduces penetration of the composite particles by the electrolyte solvent, which can cause SEI formation therein, reducing the overall surface area and providing greater control over avoiding undesirable surface reactions during use.

[0109] The composite particles are preferably 300m 2 / g or less, or 250m 2 / g or less, or 200m 2 / g or less, or 150m 2 / g or less. More preferably, 2 / g or less, or 80m 2 / g or less, or 60m 2 / g or less, or 50m 2 / g or less, or 40m 2 / g or less, or 30m 2 / g or less, or 25m 2 / g or less, or 20m 2 / g or less, or 15m 2 / g or less, or 10m 2 / g or less, or 5m 2 Preferably, the composite particles have a particle size of 30m / g or less. 2 / g or less, or 25m 2 / g or less, or 20m 2 / g or less, or 15m 2 / g or less, or 10m 2 / g or less, or 5m 2The composite particles have a BET surface area of ​​0.1 m / g or less. Generally, a low BET surface area is preferred to minimize the formation of a solid electrolyte interfacial (SEI) layer on the surface of the composite particles during the first charge-discharge cycles of the anode. However, if the BET surface area is too low, the charge rate and capacity will be unacceptably low because the bulk of the electroactive material will be inaccessible to metal ions in the surrounding electrolyte. For example, the BET surface area may be 0.1 m / g or less. 2 / g~100m 2 / g, or 0.1m 2 / g~80m 2 / g, or 0.5m 2 / g~60m 2 / g, or 0.5m 2 / g~40m 2 / g, or 1m 2 / g~30m 2 / g, or 1m 2 / g~25m 2 / g, or 2m 2 / g~20m 2 / g.

[0110] The composite particles can have an irregular or spheroidal shape. Spheroidal particles, as defined herein, can include both spherical and spheroidal particles, and the shape of the composite particles of the present invention can be preferably defined by reference to the sphericity and aspect ratio of the particles of the present invention. Spheroidal particles have been found to be particularly suitable for dispersion in slurries without forming agglomerates. Furthermore, the use of porous spheroidal particles has surprisingly been found to provide further strength improvements when compared to irregularly shaped porous particles and porous particle fragments.

[0111] The sphericity of an object is conventionally defined as the ratio of the surface area of ​​the object to the surface area of ​​a sphere, where the object and the sphere have the same volume. However, in practice, it is difficult to measure the surface area and volume of individual micron-scale particles. However, scanning electron microscopy (SEM) and dynamic image analysis, in which the shadows cast by the particles are recorded using a digital camera, can provide highly accurate two-dimensional projection images of micron-scale particles. The term "sphericity" as used herein shall be understood as the ratio of the area of ​​the particle projection to the area of ​​a circle, where the particle projection and the circle have the same circumference. Thus, for an individual particle, the sphericity S can be defined as follows:

number

number

[0112] As used herein, the term "spheroidal" as applied to the composite particles of the present invention shall be understood to refer to materials having an average sphericity of at least 0.70. The composite particles of the present invention preferably have an average sphericity of at least 0.85, more preferably at least 0.90, more preferably at least 0.92, more preferably at least 0.93, more preferably at least 0.94, and more preferably at least 0.95. The composite particles can optionally have an average sphericity of at least 0.96, or at least 0.97, or at least 0.98, or at least 0.99.

[0113] It will be understood that the circumference and area of ​​a two-dimensional particle projection image will depend on the particle orientation for any particle that is not perfectly spheroidal. However, the effect of particle orientation can be offset by reporting sphericity and aspect ratio as average values ​​obtained from multiple particles with random orientation. Many SEM instruments and dynamic image analyzers are commercially available that can quickly and reliably determine the sphericity and aspect ratio of particulate materials. Unless otherwise specified, sphericity values ​​specified or reported herein are measured using a CamSizer XT particle analyzer manufactured by Retsch Technology GmbH. The CamSizer XT is a dynamic image analyzer capable of obtaining highly accurate size and shape distributions of particulate materials in sample volumes ranging from 100 mg to 100 g, allowing properties such as average sphericity and aspect ratio to be directly calculated using this instrument.

[0114] The composite particles may be further characterized by their performance under thermogravimetric analysis (TGA) in air, which is based on the principle that when an electroactive material is oxidized in air and at elevated temperatures, a weight gain is observed.

[0115] As defined herein, "surface silicon" is calculated from the initial mass gain of a TGA trace from a minimum between 150°C and 500°C to a maximum mass measured in the temperature range between 550°C and 650°C, with the TGA performed in air at a heating rate of 10°C / min. This mass gain is assumed to result from oxidation of the surface silicon and is therefore calculated according to the following formula: Y=1.875×[(M max -M min ) / M f ]×100% where Y is the percentage of surface silicon as a proportion of the total silicon in the sample, and M max is the maximum mass of the sample measured in the temperature range between 550°C and 650°C, and M min is the minimum mass of the sample at temperatures above 150°C and below 500°C, and M fThe percentage of surface silicon as a proportion of the total amount of silicon can be determined according to 1.875 (where 1.875 is the mass of the sample at the completion of oxidation at 1400°C). For completeness, it will be understood that 1.875 is the molar mass ratio of SiO to O (i.e., the mass ratio of SiO formed to the mass increase due to the addition of oxygen). Typically, TGA analysis is performed using a sample size of 10 mg ± 2 mg.

[0116] It has been found that reversible capacity retention over multiple charge / discharge cycles is significantly improved when the surface silicon, as determined by the TGA method described above, is at least 20% by weight of the total silicon in the material. Preferably, at least 22% by weight of the silicon, or at least 25% by weight, or at least 30% by weight, or at least 35% by weight of the silicon, or at least 40% by weight, or at least 45% by weight of the silicon is surface silicon as determined by thermogravimetric analysis (TGA).

[0117] In addition to a high surface silicon content, the particulate material of the present invention preferably has a low content of coarse bulk silicon as determined by TGA. Crude bulk silicon is defined herein as silicon that undergoes oxidation above 800°C as determined by TGA, where the TGA is performed in air at a heating rate of 10°C / min. Therefore, the crude bulk silicon content is calculated by the following formula: Z = 1.875 × [(M f -M 800 ) / M f ]×100% where Z is the percentage of unoxidized silicon at 800°C and M 800 is the mass of the sample at 800 °C, and M fis the mass of ash at completion of oxidation at 1400°C). For the purposes of this analysis, any mass increase above 800°C corresponds to the oxidation of silicon to SiO2, and the total mass at completion of oxidation is assumed to be SiO2. Typically, TGA analysis is performed using a sample size of 10 mg ± 2 mg.

[0118] Silicon that undergoes oxidation above 800° C. is less desirable. Preferably, no more than 10% by weight of the silicon is crude bulk silicon as determined by TGA, or no more than 8% by weight, or no more than 6% by weight, or no more than 5% by weight, or no more than 4% by weight, or no more than 3% by weight, or no more than 2% by weight, or no more than 1.5% by weight.

[0119] Preferably, at least 20% by weight of the silicon is surface silicon and not more than 10% by weight of the silicon is crude bulk silicon, both determined by TGA. More preferably, at least 30% by weight of the silicon is surface silicon and not more than 10% by weight of the silicon is crude bulk silicon, both determined by TGA. More preferably, at least 35% by weight of the silicon is surface silicon and not more than 8% by weight of the silicon is crude bulk silicon, both determined by TGA. More preferably, at least 40% by weight of the silicon is surface silicon and not more than 5% by weight of the silicon is crude bulk silicon, both determined by TGA. More preferably, at least 45% by weight of the silicon is surface silicon and not more than 2% by weight of the silicon is crude bulk silicon, both determined by TGA.

[0120] The composite particles preferably have a specific charge capacity of 1200 mAh / g to 2340 mAh / g upon initial lithiation. Preferably, the composite particles have a specific charge capacity of at least 1400 mAh / g upon initial lithiation.

[0121] The composite particles may include a coating of a lithium-ion permeable material, such as a carbon coating. The lithium-ion permeable material coating has the advantage of further reducing the BET surface area of ​​the composite particles by smoothing any surface defects and filling any remaining surface pore structure, thereby further reducing first-cycle losses. Furthermore, the lithium-ion permeable material coating improves the conductivity of the composite particle surface, reducing the need for conductive additives in the electrode composition, and creating an optimal surface for the formation of a stable SEI layer, resulting in improved capacity retention with cycling.

[0122] Reducing the surface area of ​​the composite particles also has the effect of reducing the amount of binder required to form an electrode active layer containing the composite particles. Excess binder is known to contribute to reduced rate performance. A further advantage of the present invention is that the filler contributes to improving the compressive strength of the composite particles by providing structural reinforcement to the porous particle skeleton.

[0123] When a carbon coating is present, the composite particles are preferably 150 mm thick. 2 / g or less, or 100m 2 / g or less, or 80m 2 / g or less, or 60m 2 / g or less, or 40m 2 / g or less, or 30m 2 / g or less, or 25m 2 / g or less, or 20m 2 / g or less, or 15m 2 / g or less, or 10m 2 / g or less, or 5m 2 / g or less, or 3m 2 / g or less BET surface area.

[0124] In a second aspect, the present invention provides a method for preparing composite particles, comprising the steps of: (a) The total pore volume of micropores and mesopores as measured by gas adsorption is 0.4 cm 3 / g~2.2cm 3 / g range of micropores and / or mesopores providing a number of porous particles; (b) contacting the porous particles with a precursor of an electroactive material at a temperature effective to cause deposition of a plurality of electroactive material domains in the pores of the porous particles; (c) forming a plurality of modifier material domains in the pores of the porous particles and adjacent to the electroactive material domains deposited in step (b); (d) contacting the particles from step (c) with a precursor of an electroactive material at a temperature effective to cause deposition of additional electroactive material domains in the pores of the porous particles and adjacent to the modifier material domains formed in step (c); The present invention provides a method comprising:

[0125] The method of the present invention is therefore a multi-step process comprising, in sequence, a first step of depositing an electroactive material, a step of forming a modifier material adjacent to the electroactive material, and a further step of depositing an electroactive material adjacent to the modifier material. This sequence of steps results in a product from step (d) where at least a portion of the modifier material domain is located between the electroactive material deposited in step (b) and the electroactive material deposited in step (d). The product of the method of the second aspect of the present invention is therefore a particulate material according to the first aspect of the present invention.

[0126] As discussed above, the porous particles used in step (a) form a porous particle skeleton in the composite particle. The term "porous particle skeleton" is used in the context of the composite particle product, while the term "porous particle" is used to describe the starting material that ultimately forms the porous particle skeleton. Thus, the porous particles used in step (a) of the method of the second aspect of the present invention may have any of the features of the porous particle skeleton described herein in the context of the first aspect of the present invention. The features of the porous particle skeleton may optionally be combined with any of the additional features of the porous particle set forth below.

[0127] Generally, porous particles have a D in the range of 0.5 μm to 200 μm.50 Optionally, the porous particles may have a particle size D 50 The particle size may be at least 1 μm, or at least 1.5 μm, or at least 2 μm, or at least 2.5 μm, or at least 3 μm, or at least 4 μm, or at least 5 μm. Optionally, the D of the porous particles 50 The particle size may be 150 μm or less, or 100 μm or less, or 70 μm or less, or 50 μm or less, or 40 μm or less, or 30 μm or less, or 25 μm or less, or 20 μm or less, or 18 μm or less, or 15 μm or less, or 12 μm or less, or 10 μm or less, or 8 μm or less.

[0128] For example, the porous particles may be 0.5 μm to 150 μm, or 0.5 μm to 100 μm, or 0.5 μm to 50 μm, or 0.5 μm to 30 μm, or 1 μm to 25 μm, or 1 μm to 20 μm, or 2 μm to 25 μm, or 2 μm to 20 μm, or 2 μm to 18 μm, or 2 μm to 15 μm, or 2 μm to 12 μm, or 2.5 D in the range of μm to 15 μm, or 2.5 μm to 12 μm, or 2 μm to 10 μm, or 3 μm to 20 μm, or 3 μm to 18 μm, or 3 μm to 15 μm, or 4 μm to 18 μm, or 4 μm to 15 μm, or 4 μm to 12 μm, or 5 μm to 15 μm, or 5 μm to 12 μm, or 5 μm to 10 μm, or 5 μm to 8 μm 50 Particles within these size ranges and having porosities and pore size distributions as set forth herein are ideally suited for the preparation of composite particles for use in anodes for metal-ion batteries by the CVI process.

[0129] D of porous particles 10 The particle size is preferably at least 0.2 μm, or at least 0.5 μm, or at least 0.8 μm, or at least 1 μm, or at least 1.5 μm, or at least 2 μm. 10 Maintaining particle size above 0.2 μm reduces the possibility of undesired aggregation of submicron-sized particles and improves the dispersibility of composite particles. will be improved.

[0130] D of porous particles 90 The particle size is preferably 300 μm or less, or 250 μm or less, or 200 μm or less, or 150 μm or less, or 100 μm or less, or 80 μm or less, or 60 μm or less, or 40 μm or less, or 30 μm or less, or 25 μm or less, or 20 μm or less.

[0131] The porous particles preferably have a narrow particle size distribution span. For example, the particle size distribution span (D 90 -D 10 ) / D 50 (defined as) is preferably 5 or less, more preferably 4 or less, more preferably 3 or less, more preferably 2 or less, and most preferably 1.5 or less. By maintaining a narrow particle size distribution span, efficient packing of particles into a dense powder bed is more easily achieved.

[0132] The porous particles preferably have a thickness of at least 100 mm 2 / g, or at least 500m 2 / g, or at least 750m 2 / g, or at least 1000m 2 / g. As used herein, the term "BET surface area" should be taken to refer to the surface area per unit mass calculated from measurements of the physical adsorption of gas molecules on a solid surface using the Brunauer-Emmett-Teller theory and in accordance with ISO 9277. Preferably, the BET surface area of ​​the porous particles is 4000 m 2 / g or less, or 3500m 2 / g or less, or 3250m 2 / g or less, or 3000m 2 / g, or 2500m 2 / g or less, or 2000m 2 For example, the porous particles have a particle size of 100 m 2 / g~4000m 2 / g, or 500m 2 / g~4000m 2 / g, or 750m 2 / g~3500m 2 / g, or 1000m 2 / g~3250m 2 / g, 1000m 2 / g~3000m 2 / g, or 1000m 2 / g~2500m 2 / g, or 1000m 2 / g~2000m 2 / g.

[0133] The porous particles may have an average sphericity (as defined above) of greater than 0.5. Preferably, the porous particles have an average sphericity of at least 0.55, or at least 0.6, or at least 0.65, or at least 0.7, or at least 0.75, or at least 0.8, or at least 0.85. Preferably, the porous particles have an average sphericity of at least 0.90, or at least 0.92, or at least 0.93, or at least 0.94, or at least 0.95.

[0134] Preferably, the porous particles are (i) 0.4 cm 3 / g~2.2cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD of 20 nm or less 50 Pore ​​diameter, preferably 30 nm or less PD 90 Pore ​​diameter, preferably PD of 15 nm or less 30 Pore ​​size, and (iii) D in the range of 0.5 μm to 30 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0135] More preferably, the porous particles are (i) 0.6 cm 3 / g~1.8cm 3the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD less than 10 nm 50 Pore ​​diameter, preferably 20 nm or less PD 90 Pore ​​diameter, preferably 8 nm or less PD 30 Pore ​​size, and (iii) D in the range of 1 μm to 25 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0136] More preferably, the porous particles are (i) 0.7 cm 3 / g~1.6cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD less than 10 nm 50 Pore ​​diameter, preferably 20 nm or less PD 90 Pore ​​diameter, preferably 8 nm or less PD 30 Pore ​​size, and (iii) D in the range of 1 μm to 20 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0137] More preferably, the porous particles are (i) 0.7 cm 3 / g~1.5cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD of 5 nm or less 50 Pore ​​diameter, preferably PD of 10 nm or less 90 Pore ​​diameter, preferably 3 nm or less PD 30 Pore ​​size, and (iii) D in the range of 2 μm to 20 μm50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0138] More preferably, the porous particles are (i) 0.7 cm 3 / g~1.4cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD of 5 nm or less 50 Pore ​​diameter, preferably PD of 10 nm or less 90 Pore ​​diameter, preferably 3 nm or less PD 30 Pore ​​size, and (iii) D in the range of 2 μm to 20 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0139] More preferably, the porous particles are (i) 0.7 cm 3 / g~1.4cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD of 5 nm or less 50 Pore ​​diameter, preferably PD of 10 nm or less 90 Pore ​​diameter, preferably 3 nm or less PD 30 Pore ​​size, and (iii) D in the range of 2 μm to 18 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0140] More preferably, the porous particles are (i) 0.7 cm 3 / g~1.4cm 3 the total pore volume of micropores and mesopores as measured by nitrogen gas adsorption in the range of 1 / g; (ii) PD of 2 nm or less 50 Pore ​​diameter, preferably 5 nm or less PD 90 Pore ​​diameter, preferably 1 nm or less PD 30 Pore ​​size, and (iii) D in the range of 2 μm to 15 μm 50 particle size, and optionally, (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), It has.

[0141] The composite particles are (i) D of at least 0.5 μm 10 particle size, (ii) D of 50 μm or less 90 particle size, and (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0142] The composite particles are (i) D of at least 0.8 μm 10 particle size, (ii) D of 40 μm or less 90 particle size, and (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0143] The composite particles are (i) D of at least 0.8 μm 10 particle size, (ii) D of 30 μm or less 90 particle size, and (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0144] The composite particles are (i) D of at least 1 μm 10 particle size, (ii) D of 25 μm or less 90 particle size, and (iii) 0.25 cm 3 / g or less total volume of micropores and mesopores, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0145] The composite particles are (i) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (ii) 40 wt% to 70 wt% silicon, based on the total mass of the composite particles; and (iii) 30 m 2 / g or less BET surface area, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0146] The composite particles are (i) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (ii) 40 wt% to 60 wt% silicon, based on the total mass of the composite particles; and (iii) 20m 2 / g or less BET surface area, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0147] The composite particles are (i) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (ii) 40 wt% to 60 wt% silicon, based on the total mass of the composite particles; and (iii) 15m 2 / g or less BET surface area, and optionally (iv) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0148] Composite particles having these preferred total oxygen contents, silicon contents and BET surface areas are believed to have improved cycle life and energy capacity.

[0149] The composite particles are (i) D of at least 0.5 μm 10 particle size, (ii) D of 50 μm or less 90 particle size, (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, (iv) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (v) 40 wt% to 70 wt% silicon, based on the total mass of the composite particles; and (vi) 30 m 2 / g or less BET surface area, and optionally (vii) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0150] The composite particles are (i) D of at least 0.8 μm 10 particle size, (ii) D of 40 μm or less 90 particle size, (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, (iv) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (v) 40 wt% to 60 wt% silicon, based on the total mass of the composite particles; and (vi) 20 m 2 / g or less BET surface area, and optionally (vii) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0151] The composite particles are (i) D of at least 0.8 μm 10 particle size, (ii) D of 30 μm or less 90 particle size, (iii) 0.35 cm 3 / g or less total volume of micropores and mesopores, (iv) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (v) 40 wt% to 60 wt% silicon, based on the total mass of the composite particles; and (vi) 15 m 2 / g or less BET surface area, and optionally (vii) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0152] The composite particles are (i) D of at least 1 μm 10 particle size, (ii) D of 25 μm or less 90 particle size, (iii) 0.25 cm 3 / g or less total volume of micropores and mesopores, (iv) a total oxygen content of less than 5% by weight, based on the total mass of the composite particles; (v) 40 wt% to 60 wt% silicon, based on the total mass of the composite particles; and (vi) 15 m 2 / g or less BET surface area, and optionally (vii) A particle size distribution span (D 90 -D 10 ) / D 50 ), may have

[0153] The aforementioned preferred features of the porous particles also apply to the porous particle scaffold in the composite particles of the first aspect of the invention.

[0154] The electroactive materials deposited in steps (b) and (d) may be the same or different and may optionally be independently selected from silicon, tin, germanium, aluminum, and mixtures and alloys thereof. A preferred electroactive material is silicon. Preferably, the electroactive material deposited in at least one of steps (b) and (d) is silicon. More preferably, both the electroactive materials deposited in each of steps (b) and (d) are silicon.

[0155] Suitable precursors for silicon include silane (SiH4), disilane (Si2H6), trisilane (Si3H8), and tetrasilane (Si4H 10 ), methylsilane (CH3SiH3) , dimethylsilane ((CH3)2SiH2), or chlorosilanes such as trichlorosilane (HSiCl3) or methylchlorosilanes such as methyltrichlorosilane (CH3SiCl3) or dimethyldichlorosilane ((CH3)2SiCl2). The preferred precursor of silicon is silane.

[0156] Suitable precursors of tin include bis[bis(trimethylsilyl)amino]tin(II) ([[(CH3)3Si]2N]2Sn), tetraallyltin ((H2C=CHCH2)4Sn), tetrakis(diethylamido)tin(IV) ([(C2H5)2N]4Sn), tetrakis(dimethylamido)tin(IV) ([(CH3)2N]4Sn), tetramethyltin (Sn(CH3)4), tetravinyltin (Sn(CH=CH2)4), tin(II) acetylacetonate (C 10 H 14 O4Sn), trimethyl(phenylethynyl)tin (C6H5C≡CSn(CH3)3), and trimethyl(phenyl)tin (C6H5Sn(CH3)3). The preferred precursor of tin is tetramethyltin.

[0157] Suitable precursors of aluminum include aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (Al(OCC(CH)CHCOC(CH))), trimethylaluminum ((CH)Al), and tris(dimethylamido)aluminum(III) (Al(N(CH))). The preferred precursor of aluminum is trimethylaluminum.

[0158] Suitable precursors of germanium include germane (GeH), hexamethyldigermanium ((CH)GeGe(CH), tetramethylgermanium ((CH)Ge), tributylgermanium hydride ([CH(CH)]GeH), triethylgermanium hydride ((CH)GeH), and triphenylgermanium hydride ((CH)GeH). The preferred precursor of germanium is germane.

[0159] When the precursor is a chlorinated compound, such as a chlorosilane, the precursor is used in a mixture with hydrogen gas, preferably in at least a 1:1 atomic ratio of hydrogen to chlorine.

[0160] Optionally, the precursor is chlorine-free, meaning that the precursor contains less than 1% by weight, preferably less than 0.1% by weight, preferably less than 0.01% by weight of chlorine-containing compounds.

[0161] In steps (b) and (d), the precursors may be used in pure (or substantially pure) form or as a dilute mixture with an inert carrier gas, such as nitrogen or argon. When in a dilute mixture with an inert carrier gas, the precursors may be used in an amount ranging from 1% to 95% by volume, or from 1% to 85% by volume, or from 1% to 70% by volume, or from 1% to 50% by volume, or from 2% to 40% by volume, or from 5% to 30% by volume, or from 5% to 25% by volume, based on the total gas volume of the precursor and the inert carrier gas. In accordance with conventional practice for working in an inert atmosphere, the presence of oxygen should be minimized to prevent undesired oxidation of the deposited electroactive material. Preferably, the oxygen content is less than 0.01% by volume, more preferably less than 0.001% by volume, based on the total volume of gas used in steps (b) and (d).

[0162] The temperatures in steps (b) and (d) can be any temperature effective to decompose the precursor to form the electroactive material. Preferably, the temperatures in steps (b) and (d) are independently in the range of 300°C to 800°C, or 350°C to 800°C, or 380°C to 700°C, or 380°C to 650°C, or 380°C to 600°C, or 380°C to 550°C, or 380°C to 500°C, or 400°C to 450°C, or 450°C to 500°C. More preferably, Preferably, the temperatures in steps (b) and (d) are each independently in the range of 380° C. to 500° C., preferably 420° C. to 480° C. Optionally, the temperatures are substantially the same in steps (b) and (d).

[0163] The operating pressure in steps (b) and (d) may be below atmospheric pressure, above atmospheric pressure, or at atmospheric pressure. Optionally, the pressure in at least one of steps (b) and (d) is maintained below 200 kPa, or at or below 150 kPa, or at or below 120 kPa, or at or below 110 kPa, or at or below 100 kPa, or at or below 90 kPa, or at or below 80 kPa, or at or below 70 kPa, or at or below 60 kPa, or at or below 50 kPa.

[0164] For example, the pressure in at least step (b) is maintained at less than 200 kPa, or 150 kPa or less, or 120 kPa or less, or 110 kPa or less, or 100 kPa or less, or 90 kPa or less, or 80 kPa or less, or 70 kPa or less, or 60 kPa or less, or 50 kPa or less.

[0165] Optionally, the pressure in both step (b) and step (d) may be maintained at less than 200 kPa, or 150 kPa or less, or 120 kPa or less, or 110 kPa or less, or 100 kPa or less, or 90 kPa or less, or 80 kPa or less, or 70 kPa or less, or 60 kPa or less, or 50 kPa or less.

[0166] References to pressure in any step of the claimed process refer to the absolute pressure in the reaction zone, which may include any suitable type of reactor vessel.

[0167] Deposition of electroactive materials by CVI results in the removal of by-products, particularly by-product gases such as hydrogen. Steps (b) and / or (d) preferably further comprise separating the by-products. Separation of the by-products from the particles formed in steps (b) and / or (d) can be achieved by flushing the reactor with an inert gas and / or by evacuating the reactor to reduce the pressure. For example, separation of the by-products from the intermediate particles formed in step (b) can be achieved by evacuating the reactor to a pressure of less than 100 kPa, or less than 80 kPa, or less than 60 kPa, or less than 40 kPa, or less than 20 kPa, or less than 10 kPa, or less than 5 kPa, or less than 2 kPa, or less than 1 kPa. Evacuating the reactor to a low pressure can be effective not only to remove gas-phase by-products, but also to desorb any by-products that may adsorb on the surface of the deposited electroactive material.

[0168] The modifier material formed in step (c) may optionally be a passivation layer formed on the surface of the electroactive material deposited in step (b). Accordingly, step (c) may further comprise contacting the intermediate particles from step (b) with a passivator. As noted above, the passivator is a compound or mixture of compounds capable of reacting with the surface of the electroactive material deposited in step (b) to form a modified surface. Any of the passivators described in connection with the first aspect of the present invention may be used in step (c).

[0169] The contacting of the electroactive material with the passivating agent in step (c) may be carried out at a temperature in the range of 25°C to 800°C, preferably 50°C to 500°C, more preferably 100°C to 300°C.

[0170] The formation of the native oxide layer is exothermic and thus requires careful process control to prevent overheating or even combustion of the particulate material. If the modifier material formed in step (c) is a native oxide layer, step (c) involves cooling the material formed in step (b) to less than 300°C, preferably less than 200°C, optionally less than 100°C, before contacting the surface of the electroactive material domain with an oxygen-containing gas. This may include cooling.

[0171] The modifier material formed in step (c) may be a nitride of the electroactive material domain. Step (c) may include contacting ammonia with the surface of the electroactive material domain. The nitride layer can be formed by contacting the surface of the electroactive material domain with ammonia at a temperature in the range of 200°C to 700°C, preferably 400°C to 700°C, more preferably 400°C to 600°C. Then, if necessary, the temperature is raised to the range of 500°C to 1000°C to form a nitride surface (e.g., a silicon nitride surface of the formula SiN x (where x ≤ 4 / 3)). For example, when using ammonia, step (c) may be carried out at the same or a similar temperature as that used for depositing the electroactive material domain in step (b). Since stoichiometric silicon nitride is conductive, this step will also result in the formation of a conductive network that enables more rapid charging and discharging of the electroactive material.

[0172] Another type of modifier material is an oxynitride layer. Step (c) may include exposing the surface of the electroactive material domain to ammonia (or another nitrogen-containing molecule) and oxygen gas. If the electroactive material domain contains silicon, the modifier material domain may include silicon oxynitride of the formula SiO x N y (where 0 < x < 2, 0 < y < 4 / 3, and 0 < (2x + 3y) ≤ 4). The silicon nitride is preferably amorphous silicon oxynitride.

[0173] As a further option, an amorphous or nanocrystalline carbide layer may be formed. Step (c) may include contacting the surface of the electroactive material domain with a carbon-containing precursor, such as methane or ethylene, at a temperature in the range of 250 °C to 700 °C. At lower temperatures, covalent bonds are formed between the electroactive material surface and the carbon-containing precursor, which is converted into a single layer of crystalline silicon carbide as the temperature rises. If the electroactive material domain contains silicon, the modifier material domain may contain silicon carbide of the formula SiC x (where 0 < x ≦ 1). The silicon carbide is preferably amorphous silicon carbide.

[0174] Other suitable passivating agents include compounds containing alkene, alkyne or carbonyl functional groups, more preferably terminal alkenes, terminal alkynes, aldehyde or ketone groups. Suitable passivating agents of these types are described above.

[0175] Other suitable passivating agents include compounds containing active hydrogen atoms bonded to oxygen, nitrogen, sulfur or phosphorus. For example, the passivating agent may be an alcohol, an amine, a thiol or a phosphine. The reaction of the -XH group with the hydride group on the electroactive material surface is understood to result in the removal of H2 and the formation of a direct bond between X and the electroactive material surface. Suitable passivating agents of these types are described above.

[0176] The modifier material formed in step (c) may optionally include a pyrolytic carbon material deposited on the electroactive material surface by thermal decomposition of the carbon-containing precursor, i.e., by chemical vapor infiltration (CVI) method. The deposition of the pyrolytic carbon material in step (c) may be suitable for forming a conductive network between electroactive material domains that can promote electron transfer within the composite particles. Step (c) may thus include contacting the intermediate particles resulting from step (b) with a carbon-containing precursor, preferably a hydrocarbon, at a temperature effective to cause deposition of the pyrolytic carbon material in the pores of the intermediate particles.

[0177] Suitable hydrocarbons include polycyclic hydrocarbons containing 10 to 25 carbon atoms and, optionally, 1 to 3 heteroatoms, and optionally polycyclic aromatic hydrocarbons such as naphthalene, substituted naphthalenes, e.g., dihydroxynaphthalene, anthracene, tetracene, pentacene, fluorene, acenaphthene, phenanthrene, fluoranthene, pyrene, chrysene, perylene, Suitable pyrolytic carbon precursors include those selected from the group consisting of coronene, fluorenone, anthraquinone, anthrone, and alkyl-substituted derivatives thereof. Suitable pyrolytic carbon precursors also include bicyclic monoterpenoids, optionally selected from camphor, borneol, eucalyptol, camphene, careen, sabinene, thujene, and pinene. Further suitable pyrolytic carbon precursors include those selected from the group consisting of C2-C 10 The hydrocarbons include, optionally, alkanes, alkenes, alkynes, cycloalkanes, cycloalkenes, and arenes, such as methane, ethylene, propylene, limonene, styrene, cyclohexane, cyclohexene, α-terpinene, and acetylene. Other suitable pyrolytic carbon precursors include phthalocyanine, sucrose, starch, graphene oxide, reduced graphene oxide, pyrene, perhydropyrene, triphenylene, tetracene, benzopyrene, perylene, coronene, and chrysene. A preferred carbon precursor is acetylene.

[0178] Suitable temperatures for depositing the pyrolytic carbon material in step (c) range from 300°C to 800°C, or from 400°C to 800°C. For example, the temperature may be 750°C or less, or 700°C or less, or 680°C or less, or 660°C or less, or 640°C or less, or 620°C or less, or 600°C or less, or 580°C or less, or 560°C or less, or 540°C or less, or 520°C or less, or 500°C or less. The minimum temperature will vary depending on the type of carbon precursor used. Preferably, the temperature is at least 300°C, or at least 350°C, or at least 400°C, or at least 450°C, or at least 500°C.

[0179] The carbon-containing precursor used in step (c) may be used in pure form or in a mixture diluted with an inert carrier gas such as nitrogen or argon. For example, the carbon-containing precursor may be used in an amount ranging from 0.1% to 100% by volume, or from 0.5% to 20% by volume, or from 1% to 10% by volume, or from 1% to 5% by volume, based on the total volume of precursor and inert carrier gas. The presence of oxygen should be minimized to prevent undesired oxidation of the deposited electroactive material. Preferably, the oxygen content is less than 0.01% by volume, more preferably less than 0.001% by volume, based on the total volume of gas.

[0180] When a pyrolytic carbon material is deposited in step (c), the same compound can function as both the passivator and the pyrolytic carbon precursor. For example, if styrene is selected as the pyrolytic carbon precursor, it will also function as the passivator, provided the intermediate particles from step (b) are not exposed to oxygen prior to contact with the styrene. In this case, the passivation and deposition of the conductive carbon material during the process can be carried out simultaneously, for example, at temperatures ranging from 300°C to 700°C. Alternatively, the passivation and deposition of the conductive carbon material can be carried out sequentially if the passivator and pyrolytic carbon precursor are the same material, but the deposition of the pyrolytic carbon precursor is carried out at a higher temperature than the passivation. For example, passivation can be carried out at temperatures ranging from 25°C to less than 300°C, and the deposition of the pyrolytic carbon can be carried out at temperatures ranging from 300°C to 700°C. These two steps can be suitably carried out sequentially by increasing the temperature while maintaining contact with the compound that functions as both the passivator and the pyrolytic carbon precursor. At lower temperatures (e.g., in the range of 25°C to less than 300°C), passivation will be the dominant process. As the temperature increases (e.g., to 300°C to 700°C), pyrolytic carbon deposition is likely to ensue.

[0181] As a further option, step (c) may comprise depositing a layer of a conductive metal or metal alloy as a modifier material on the surface of the electroactive material domain. The conductive metal layer or metal alloy may be obtained by chemical vapor infiltration (CVI). Examples of suitable conductive metals include silver, gold, copper, and titanium.

[0182] The formation of the conductive metal or metal alloy modifier material in step (c) may optionally be followed by passivation of the electroactive material domain surface by one of the processes described above. Thus, the modifier material formed in step (c) may include both a passivation layer and a conductive metal or metal alloy layer on the surface of the electroactive material domain.

[0183] As a further alternative, step (c) may include forming a modifier material domain comprising an electroactive material comprising a dopant selected from the group consisting of boron, aluminum, gallium, indium, phosphorus, arsenic, antimony, and bismuth. The doped electroactive material may be formed by a CVI process in which the porous particles are simultaneously contacted with both a precursor of the electroactive material and the dopant. Alternatively, the doped electroactive material may be formed by contacting the dopant with the deposited electroactive material.

[0184] As a further alternative, step (c) may include forming a solid state electrolyte as the modifier material.

[0185] As a further alternative, step (c) may include forming an inert filler as the modifier material.

[0186] Depending on the amount of electroactive material to be deposited in each step, the method of the present invention may be operated as a multi-pass process in which steps (c) and (d) are repeated as many times as necessary to deposit the target amount of electroactive material. For example, steps (c) and (d) may be performed 2 to 15 times, resulting in 3 to 16 deposition steps of electroactive material, including repetitions of steps (b) and (d).

[0187] When steps (c) and (d) are repeated, each process in steps (c) and (d) is independently as described above. For example, each repetition of step (c) may include the formation of the same or a different modifier material. Similarly, the electroactive material deposited in each repetition of step (d) may be the same or different, and may again be the same or different from the electroactive material deposited in step (b). Preferably, the electroactive material deposited in at least one of step (b) and repeated step (d) is silicon. More preferably, the electroactive material deposited in each of step (b) and repeated step (d) is silicon.

[0188] When steps (c) and (d) are repeated, the particles used during the repetition of step (c) are intermediate particles obtained from the preceding step (d). Thus, any reference herein to "particles from step (b)" in the description of step (c) should be interpreted as "particles from the preceding step (d)" when step (c) is optionally repeated.

[0189] The method of the present invention optionally comprises: (e) forming a plurality of modifier material domains in the pores and / or on the exterior surface of the composite particles from step (d); Further includes:

[0190] Step (e) is performed immediately after the final electroactive material deposition step (i.e., step (d), or the final repetition of step (d) if steps (c) and (d) are repeated). The formation of the modifier material domain in step (e) is a similar process to step (c) described above, except that step (e) occurs after the final electroactive material deposition step (the final step (d)), while step (c) occurs between successive electroactive material deposition steps. Any modifier materials and deposition conditions set forth above in connection with step (c) also apply to step (e).

[0191] The modifier material domains formed in step (e) may comprise the same or different modifier material as the modifier material domains formed in step (c).

[0192] Optionally, step (e) comprises contacting the composite particles from step (d) with a passivating agent. The preferred passivating agents and passivating conditions set forth above in relation to step (c) also apply to the passivation in step (e).

[0193] The modifier material domains formed in step (e) may be native oxides of the electroactive material, in which case the modifier material domains formed in step (c) (and any repetitions of step (c)) are preferably not native oxides of the electroactive material.

[0194] Optionally, step (e) includes depositing a lithium-ion permeable material within the pores and / or on the outer surface of the composite particles from step (d), which results in further improvement in the performance of the composite particles when used as electroactive materials for lithium-ion batteries by reducing the surface area of ​​the composite particles and by blocking electroactive material domains from access to the electrolyte.

[0195] The lithium ion permeable material may be deposited immediately after the last electroactive material deposition step (i.e., step (d), or after the last step (d) if steps (c) and (d) are repeated one or more times). Alternatively, the passivation step in step (e), as discussed above, may be first carried out before depositing the lithium ion permeable material.

[0196] A suitable lithium ion permeable material is a pyrolytic carbon material, which can be obtained by chemical vapor infiltration (CVI), i.e., by pyrolysis of a volatile carbon-containing gas (e.g., ethylene) onto the surface of silicon-containing composite particles.

[0197] A suitable process for depositing a pyrolyzable carbon material includes combining the composite particles from step (d) with a pyrolyzable carbon precursor and heating the pyrolyzable carbon precursor to a temperature effective to cause deposition of a pyrolyzable conductive carbon material within the pores and / or on the exterior surfaces of the composite particles.

[0198] The preferred pyrolyzable carbon precursors and pyrolysis conditions set forth above in relation to step (c) also apply to the formation of the pyrolyzable carbon material in step (e).

[0199] When the lithium ion permeable material is a pyrolytic carbon material, the same compound may function as both the passivator and the pyrolytic carbon precursor in step (e). Suitable conditions for passivating and forming a pyrolytic carbon material using the same compound as the passivator and the pyrolytic carbon precursor in step (e) are the same as those set forth above in connection with step (c).

[0200] Alternatively, different compounds may be used as the passivating agent and as the pyrolytic carbon precursor, for example, the passivating agent may be styrene and the pyrolytic carbon precursor may be a compound such as cyclohexane that is capable of forming a pyrolytic carbon material but is incapable of passivating the electroactive material surface.

[0201] In a preferred embodiment, the electroactive material deposited in steps (b) and (d) is elemental silicon, and the modifier material domains formed in step (c) are passivation layers comprising organic moieties covalently bonded to the surface of at least some of the elemental silicon domains formed in step (b). Optionally, the method includes step (e), wherein the modifier material domains formed in step (e) are silicon oxide domains formed by passivation using an oxygen-containing gas.

[0202] In a further preferred embodiment, the electroactive material deposited in steps (b) and (d) is elemental silicon, and the modifier material domains formed in step (c) are pyrolytic carbon domains. Optionally, the method includes step (e), wherein the modifier material domains formed in step (e) are silicon oxide domains formed by passivation using an oxygen-containing gas.

[0203] In a further preferred embodiment, the electroactive material deposited in steps (b) and (d) is elemental silicon, and the modifier material domains formed in step (c) are metal or metal alloy domains. Optionally, the method includes step (e), wherein the modifier material domains formed in step (e) are silicon oxide domains formed by passivation using an oxygen-containing gas.

[0204] In a further preferred embodiment, the electroactive material deposited in steps (b) and (d) is elemental silicon, and the modifier material domains formed in step (c) are silicon oxide domains formed by passivation using an oxygen-containing gas.

[0205] The process of the present invention may be carried out in any reactor capable of contacting solids and gases at elevated temperatures. The porous particles and the resulting composite particles may be present in the reactor in the form of a fixed bed of particles or in the form of a moving or stirred bed of particles.

[0206] The product resulting from the process of the invention may have any of the characteristics described herein in relation to the particulate material of the first aspect of the invention.

[0207] In a third aspect of the present invention, there is provided a composition comprising a composite particle according to the second aspect of the present invention and at least one other component. In particular, there is provided a composition comprising a composite particle according to the second aspect of the present invention and at least one other component selected from (i) a binder, (ii) a conductive additive, and (iii) an additional particulate electroactive material. The composition according to the present invention is useful as an electrode composition and can thus be used to form the active layer of an electrode.

[0208] The composition may be a hybrid electrode composition comprising the composite particles and at least one additional particulate electroactive material. Examples of the additional particulate electroactive material include graphite, hard carbon, silicon, tin, germanium, aluminum, and lead. The at least one additional particulate electroactive material is preferably selected from graphite and hard carbon. The at least one additional particulate electroactive material is most preferably graphite.

[0209] For hybrid electrode compositions, the composition may comprise 1 wt.% to 95 wt.%, or 2 wt.% to 90 wt.%, or 5 wt.% to 85 wt.%, or 10 wt.% to 80 wt.% of particulate material, based on the total dry weight of the composition. The composition preferably comprises 3 wt.% to 60 wt.%, or 3 wt.% to 50 wt.%, or 5 wt.% to 50 wt.%, or 10 wt.% to 50 wt.%, or 15 wt.% to 50 wt.% of composite particles, based on the total dry weight of the composition.

[0210] The at least one additional particulate electroactive material is suitably present in an amount of from 20% to 95% by weight, or from 25% to 90% by weight, or from 30% to 75% by weight of the at least one additional particulate electroactive material.

[0211] The at least one additional particulate electroactive material preferably has a D in the range of 10 μm to 50 μm, preferably 10 μm to 40 μm, more preferably 10 μm to 30 μm, most preferably 10 μm to 25 μm, for example 15 μm to 25 μm. 50 It has a particle size.

[0212] D of at least one additional particulate electroactive material 10 The particle size is preferably at least 5 μm, more preferably at least 6 μm, more preferably at least 7 μm, more preferably at least 8 μm, more preferably at least 9 μm, and even more preferably at least 10 μm.

[0213] D of at least one additional particulate electroactive material 90 The particle size is preferably at most 100 μm, more preferably at most 80 μm, more preferably at most 60 μm, more preferably at most 50 μm, most preferably at most 40 μm.

[0214] Preferably, the at least one additional particulate electroactive material is selected from carbon-containing particles, graphite particles, and / or hard carbon particles, wherein the graphite particles and hard carbon particles have a D in the range of 10 μm to 50 μm. 50 More preferably, the at least one additional particulate electroactive material is selected from graphite particles, wherein the graphite particles have a D in the range of 10 μm to 50 μm. 50 It has a particle size.

[0215] The composition may be a non-hybrid (i.e., "highly loaded") electrode composition that is substantially free of additional particulate electroactive material. In this context, the term "substantially free of additional particulate electroactive material" should be interpreted to mean that the composition contains less than 15 wt. %, preferably less than 10 wt. %, preferably less than 5 wt. %, preferably less than 2 wt. %, more preferably less than 1 wt. %, and more preferably less than 0.5 wt. % of any additional electroactive material (i.e., additional material capable of inserting and releasing metal ions during charging and discharging of the battery), based on the total dry weight of the composition.

[0216] Such "highly loaded" electrode compositions preferably contain at least 50% by weight, or at least 60% by weight, or at least 70% by weight, or at least 80% by weight, or at least 90% by weight of composite particles according to the invention, based on the total dry weight of the composition.

[0217] The composition may optionally contain a binder. The binder functions to adhere the composition to the current collector and maintain the integrity of the composition. Examples of binders that can be used in accordance with the present invention include polyvinylidene fluoride (PVDF), polyacrylic acid (PAA) and its alkali metal salts, modified polyacrylic acid (mPAA) and its alkali metal salts, carboxymethyl cellulose (CMC), modified carboxymethyl cellulose (mCMC), sodium carboxymethyl cellulose (Na-CMC), polyvinyl alcohol (PVA), alginates and their alkali metal salts, styrene-butadiene rubber (SBR), and polyimides. The composition may contain a mixture of binders. Preferably, the binder comprises a polymer selected from polyacrylic acid (PAA) and its alkali metal salts, modified polyacrylic acid (mPAA) and its alkali metal salts, SBR, and CMC.

[0218] The binder may suitably be present in an amount of from 0.5% to 20% by weight, preferably from 1% to 15% by weight, preferably from 2% to 10% by weight, most preferably from 5% to 10% by weight, based on the total dry weight of the composition.

[0219] The binder may optionally be present in combination with one or more additives that modify the properties of the binder, such as crosslinking promoters, coupling agents, and / or adhesion promoters.

[0220] The composition may optionally include one or more conductive additives. Preferred conductive additives are non-electroactive materials that are included to improve electrical conductivity between the electroactive components of the composition and between the electroactive components of the composition and the current collector. Conductive additives include carbon black, carbon fiber, carbon nanotubes, graphene, acetylene black, ketone, and the like. The conductive additives may be selected from tschenblack, metal fibers, metal powders, and conductive metal oxides. Preferred conductive additives include carbon black and carbon nanotubes.

[0221] The one or more conductive additives may suitably be present in a total amount of from 0.5% to 20% by weight, preferably from 1% to 15% by weight, preferably from 2% to 10% by weight, most preferably from 5% to 10% by weight, based on the total dry weight of the composition.

[0222] The present invention provides an electrode comprising a particulate material according to the present invention in electrical contact with a current collector. The particulate material used to make the electrode may be in the form of a composition of the present invention.

[0223] The term current collector, as used herein, refers to any conductive substrate capable of conducting current to and from the electroactive particles in the composition. Examples of materials that can be used as current collectors include copper, aluminum, stainless steel, nickel, titanium, and sintered carbon. Copper is a preferred material. Current collectors typically have the form of a foil or mesh having a thickness of 3 μm to 500 μm. The particulate material of the present invention can be applied to one or both sides of the current collector, preferably to a thickness ranging from 10 μm to 1 mm, e.g., 20 μm to 500 μm, or 50 μm to 200 μm.

[0224] The electrodes of the present invention can be made by combining the particulate material of the present invention with a solvent and, optionally, one or more viscosity-adjusting additives to form a slurry. The slurry is then cast onto the surface of a current collector, and the solvent is removed to form an electrode layer on the surface of the current collector. Further steps, such as heat treatment to cure any binder and / or calendaring the electrode layer, can optionally be performed. The electrode layer suitably has a thickness in the range of 20 μm to 2 mm, preferably 20 μm to 1 mm, preferably 20 μm to 500 μm, preferably 20 μm to 200 μm, preferably 20 μm to 100 μm, and preferably 20 μm to 50 μm.

[0225] Alternatively, the slurry can be formed into a free-standing film or mat comprising the particulate material of the present invention, for example, by casting the slurry onto a suitable casting template, removing the solvent, and then removing the casting template. The resulting film or mat has the form of a free-standing agglomerate, which can then be adhered to a current collector by known methods.

[0226] The electrode of the present invention can be used as an anode in a metal-ion battery. Accordingly, the present invention provides a rechargeable metal-ion battery comprising an anode comprising an electrode according to the present invention as described above, a cathode comprising a cathode active material capable of releasing and reabsorbing metal ions, and an electrolyte between the anode and the cathode.

[0227] The metal ions are preferably lithium ions. More preferably, the rechargeable metal ion batteries of the present invention are lithium ion batteries, and the cathode active material is capable of releasing and accepting lithium ions.

[0228] The cathode active material is preferably a metal oxide composite. Examples of suitable cathode active materials include LiCoO, LiCo 0.99 Al 0.01 O2, LiNiO2, LiMnO2, LiCo 0.5 Ni 0.5 O2, LiCo 0.7 Ni 0.3 O2, LiCo 0.8 Ni 0.2 O2, LiCo 0.82 Ni 0.18 O2, LiCo 0.8 Ni 0.15 Al 0.05 O2, LiNi 0.4 Co 0.3 Mn 0.3 O2 and LiNi 0.33 Co 0.33 Mn 0.34 The cathode current collector is usually made of a material with a thickness of 3 μm to 500 μm. Examples of materials that can be used as the cathode current collector include aluminum, stainless steel, nickel, titanium, and sintered carbon.

[0229] The electrolyte is preferably a non-aqueous electrolyte containing a metal salt, such as a lithium salt, and may include, but is not limited to, a non-aqueous electrolytic solution, a solid electrolyte, and an inorganic solid electrolyte. Examples of usable non-aqueous electrolytic solutions include aprotic organic solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma butyrolactone, 1,2-dimethoxyethane, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, sulfolane, methyl sulfolane, and 1,3-dimethyl-2-imidazolidinone.

[0230] Examples of organic solid electrolytes include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, and polymers containing ionically dissociable groups.

[0231] Examples of inorganic solid electrolytes include nitrides, halides, and sulfides of lithium salts such as Li5NI2, Li3N, LiI, LiSiO4, Li2SiS3, Li4SiO4, LiOH, and Li3PO4.

[0232] The lithium salt is preferably soluble in the selected solvent or mixture of solvents. Examples of suitable lithium salts include LiCl, LiBr, LiI, LiClO, LiBF, LiBCO, LiPF, LiCFSO, LiAsF, LiSbF, LiAlCl, CHSOLi, and CFSOLi.

[0233] When the electrolyte is a non-aqueous organic solution, the metal-ion battery preferably includes a separator inserted between the anode and the cathode. The separator is typically formed of an insulating material with high ion permeability and high mechanical strength. The separator typically has a pore size of 0.01 μm to 100 μm and a thickness of 5 μm to 300 μm. An example of a suitable electrode separator is a microporous polyethylene film.

[0234] The separator can be replaced with a polymer electrolyte material, in which case the polymer electrolyte material is present in both the composite anode layer and the composite cathode layer. The polymer electrolyte material can be a solid polymer electrolyte or a gel-type polymer electrolyte.

Claims

1. A particulate material comprising a plurality of composite particles, the composite particles comprising: (a) a porous particle framework containing micropores and / or mesopores, the total pore volume of the micropores and mesopores being less than 0.4 cm as measured by gas adsorption; ３ / g ~ 2.2 cm ３ / g, and a porous particle skeleton (b) a plurality of electroactive material domains and a plurality of modifier material domains disposed within an interior pore volume of the porous particulate framework, wherein at least a portion of the modifier material domains are located between adjacent electroactive material domains; Including, the porous particle framework has a volume ratio of micropores to mesopores of from 90:10 to 0:100; Particulate material.

2. The electroactive material is silicon, and the mass ratio of silicon to porous particle skeleton is [0.5×P １ ~1.9 x P １ ]: 1, where P １ is cm ３ 10. The particulate material of claim 1, wherein the total pore volume of the micropores and mesopores of the porous particle framework is expressed in units of 1 / g.

3. 2. The particulate material of claim 1, wherein the porous particle framework has a volume ratio of micropores to mesopores of from 90:10 to 30:70, or from 85:15 to 40:60, or from 80:20 to 50:50, or from 70:30 to 55:

45.

4. The total pore volume of the micropores and mesopores in the porous particle framework is 0.45 cm ３ / g ~ 2.2 cm ３ / g, or 0.5 cm ３ / g to 2cm ３ / g, or 0.55 cm ３ / g to 2cm ３ / g, or 0.6 cm ３ / g ~ 1.8 cm ３ / g, or 0.65 cm ３ / g ~ 1.8 cm ３ / g, or 0.7 cm ３ / g ~ 1.6 cm ３ / g, or 0.7 cm ３ / g to 1.5 cm ３ / g, or 0.7 cm ３ / g ~ 1.4 cm ３ 10. The particulate material of claim 1, wherein the molecular weight of the particulate material is in the range of 1 / g.

5. PD of the porous particle skeleton ５０ 2. The particulate material of claim 1, wherein the pore size is 30 nm or less, or 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1.5 nm or less.

6. PD of the porous particle skeleton ３０ 2. The particulate material of claim 1, wherein the pore size is 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1 nm or less.

7. The porous particle skeleton is 100 mm ２ / g to 4000m ２ / g, or 500m ２ / g to 4000m ２ / g, or 750m ２ / g~3500m ２ / g, or 1000m ２ / g~3250m ２ / g, or 1000m ２ / g to 3000m ２ / g, or 1000m ２ / g~2500m ２ / g, or 1000m ２ / g to 2000m ２ 10. The particulate material of claim 1, having a BET surface area in the range of 1 / g.

8. 10. The particulate material of claim 1, wherein the porous particulate skeleton is an electrically conductive porous particulate skeleton.

9. 9. The particulate material of claim 8, wherein the conductive porous particle skeleton is a conductive porous carbon particle skeleton.

10. 10. The particulate material of claim 9, wherein the electrically conductive porous carbon particle skeleton comprises at least 80% by weight carbon, or at least 85% by weight carbon, or at least 90% by weight carbon, or at least 95% by weight carbon.

11. PD of the porous particle skeleton １０ 2. The particulate material of claim 1, wherein the pore size is 10 nm or less, or 9 nm or less, or 8 nm or less, or 7 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less, or 1.5 nm or less, or 1 nm or less.

12. PD of the porous particle skeleton ９０ 2. The particulate material of claim 1, wherein the pore size is 35 nm or less, or 30 nm or less, or 25 nm or less, or 20 nm or less, or 15 nm or less, or 12 nm or less, or 10 nm or less, or 8 nm or less, or 6 nm or less, or 5 nm or less, or 4 nm or less, or 3 nm or less, or 2.5 nm or less, or 2 nm or less.

13. 10. The particulate material of claim 1, wherein each of the electroactive material domains comprises an electroactive material independently selected from silicon, tin, germanium, aluminum, and mixtures and alloys thereof.

14. 10. The particulate material of claim 1, wherein at least some of the electroactive material domains comprise or consist of silicon, or all of the electroactive material domains comprise or consist of silicon.

15. The particulate material of claim 1 , wherein the modifier material comprises one or more of carbon, nitrogen, and oxygen.

16. The modifier material is an oxide, nitride, oxynitride, or carbide passivation layer formed on the surface of at least a portion of the electroactive material domain, or the modifier material is a SiO ｘ (wherein 0<x≦2), or SiN ｘ (wherein 0<x≦4 / 3), or SiC ｘ wherein 0<x≦1, or the modifier material is a carbide selected from the formula SiN ｘ 10. The particulate material of claim 1, wherein the nitride passivation layer is formed on a surface of at least a portion of the electroactive material domains, the nitride passivation layer having the formula: where 0<x≦4 / 3.

17. 10. The particulate material of claim 1, wherein the modifier material is a passivation layer comprising carbon-containing organic moieties covalently bonded to the surface of at least some of the electroactive material domains.

18. The modifier material is covalently bonded to the surface of at least a portion of the electroactive material domains. ２～２２ The particulate material of claim 1 comprising a hydrocarbyl.

19. The modifier material is covalently bonded to the surface of at least a portion of the electroactive material domains. ２～２２ Alkyl, C ２～２２ Alkenyl, C ２～２２ Alkynyl, C ３～２２ Cycloalkyl, C ３～２２ Cycloalkenyl, C ３～２２ Cycloalkynyl or C ６～２２ The particulate material of claim 1 comprising an aralkyl.

20. the modifier material is covalently bonded to the surface of at least a portion of the electroactive material domain; 【Chemistry 1】 2. The particulate material of claim 1, selected from the group consisting of:

21. The particulate material of claim 1 , wherein the modifier material comprises a pyrolytic carbon material.

22. The particulate material of claim 1 , wherein the modifier material comprises a conductive metal or metal alloy.

23. 10. The particulate material of claim 1, wherein the modifier material comprises an electroactive material comprising a dopant selected from boron and phosphorus.

24. 10. The particulate material of claim 1, further comprising an outer modifier material domain located between the outermost electroactive material domain and the exterior of the composite particle, the modifier material comprising one or more of carbon, nitrogen, and oxygen.

25. 2. The particulate material of claim 1, wherein the composite particles comprise from 5% to 85% by weight, or from 10% to 85% by weight, or from 15% to 85% by weight, or from 20% to 80% by weight, or from 25% to 80% by weight, or from 30% to 75% by weight, or from 35% to 75% by weight, or from 40% to 70% by weight, or from 45% to 65% by weight of the electroactive material, based on the total mass of the composite particle.

26. 2. The particulate material of claim 1, wherein the composite particle comprises from 40% to 70% by weight, or from 45% to 70% by weight, or from 48% to 70% by weight, or from 50% to 70% by weight, or from 40% to 65% by weight, or from 45% to 65% by weight, or from 48% to 65% by weight, or from 50% to 65% by weight, or from 40% to 60% by weight, or from 45% to 60% by weight, or from 48% to 60% by weight, or from 50% to 60% by weight, based on the total mass of the composite particle.

27. 2. A particulate material according to claim 1, wherein the composite particles comprise from 10% to 85% by weight, or from 15% to 85% by weight, or from 20% to 80% by weight, or from 25% to 80% by weight, or from 30% to 75% by weight, or from 35% to 75% by weight, or from 40% to 70% by weight, or from 45% to 65% by weight of silicon, based on the total mass of the composite particle.

28. 2. A particulate material according to claim 1, wherein the composite particles comprise from 40% to 70% by weight, or from 45% to 70% by weight, or from 48% to 70% by weight, or from 50% to 70% by weight, or from 40% to 65% by weight, or from 45% to 65% by weight, or from 48% to 65% by weight, or from 50% to 65% by weight, or from 40% to 60% by weight, or from 45% to 60% by weight, or from 48% to 60% by weight, or from 50% to 60% by weight, based on the total mass of the composite particle.

29. 10. The particulate material of claim 1, wherein the amount of electroactive material occupies at least 25% and at most 90% of the internal pore volume of the porous particulate framework.

30. 2. The particulate material of claim 1, wherein at least 85 wt.%, or at least 90 wt.%, or at least 95 wt.%, or at least 98 wt.% of the electroactive material mass in the composite particles is located within the interior pore volume of the porous particle framework.

31. The composite particles have a D in the range of 0.5 μm to 30 μm, or 1 μm to 25 μm, or 1 μm to 20 μm, or 1 μm to 18 μm, or 1 μm to 16 μm, or 2 μm to 16 μm, or 2 μm to 14 μm, or 2 μm to 12 μm, or 2 μm to 10 μm, or 2 μm to 8 μm. ５０ 10. The particulate material of claim 1 having a particle size.

32. The composite particles are 0.1 m ２ / g to 100m ２ / g, or 0.1 m ２ / g~80m ２ / g, or 0.5m ２ / g~60m ２ / g, or 0.5m ２ / g to 40m ２ / g, or 1m ２ / g to 30m ２ / g, or 1m ２ / g~25m ２ / g, or 2m ２ / g to 20m ２ 10. The particulate material of claim 1, having a BET surface area in the range of 1 / g.

33. 2. The particulate material of claim 1, wherein the composite particles have a total oxygen content of less than 15 wt.%, or less than 10 wt.%, or less than 5 wt.%, or less than 4 wt.%, or less than 3 wt.%, or less than 2 wt.%, or less than 1 wt.%, or less than 0.5 wt.%, relative to the total mass of the composite particles.

34. 10. The particulate material of claim 1, wherein the composite particles comprise a total chlorine content of less than 100 ppm, or less than 90 ppm, or less than 80 ppm, or less than 70 ppm, based on the total mass of the composite particles.

35. 2. The particulate material of claim 1, wherein the composite particles comprise a total transition metal and alkali metal content of less than 0.5 wt. %, based on the total weight of the composite particles.

36. 10. The particulate material of claim 1, wherein the composite particles comprise 0.0001% to 0.5% by weight of zirconium, based on the total weight of the composite particles.

37. The composite particles have a D of at least 0.5 μm, or at least 0.8 μm, or at least 1 μm １０ 10. The particulate material of claim 1 having a particle size.

38. The composite particles have a D of 50 μm or less, or 40 μm or less, or 30 μm or less, or 25 μm or less, or 20 μm or less, or 15 μm or less. ９０ 10. The particulate material of claim 1 having a particle size.

39. The composite particles have a particle size distribution span (D ９０ -D １０ ) / D ５０ 2. The particulate material of claim 1, wherein

40. The composite particles are 0.35 cm ３ / g or less, or 0.25 cm ３ / g or less, or 0.15 cm ３ / g or less, or 0.1 cm ３ / g or less, or 0.05 cm ３ / g or less, or 0.03 cm ３ / g or less, or 0.02 cm ３ 10. The particulate material of claim 1, having a total volume of micropores and mesopores of less than or equal to 1000 .mu.m / g.

41. 2. The particulate material of claim 1, wherein the electroactive material is silicon and wherein no more than 10%, or no more than 8%, or no more than 6%, or no more than 5%, or no more than 4%, or no more than 3%, or no more than 2%, or no more than 1.5% by weight of the silicon is crude bulk silicon as determined by thermogravimetric analysis.

42. 2. The particulate material of claim 1, wherein the electroactive material is silicon and at least 20%, or at least 22%, or at least 25%, or at least 30%, or at least 35%, or at least 40%, or at least 45% by weight of the silicon is surface silicon as determined by thermogravimetric analysis.

43. 1. A method for preparing composite particles, comprising: (a) The total pore volume of micropores and mesopores measured by gas adsorption is 0.4 cm ３ / g ~ 2.2 cm ３ providing a plurality of porous particles comprising micropores and / or mesopores, the micropores being in the range of 0.15 to 0.15 / g; (b) contacting the porous particle with a precursor of an electroactive material at a temperature effective to cause deposition of a plurality of electroactive material domains in the pores of the porous particle; and (c) forming a plurality of modifier material domains in the pores of the porous particle adjacent to the electroactive material domains deposited in step (b). (d) contacting the porous particles from step (c) with a precursor of an electroactive material at a temperature effective to cause deposition of additional electroactive material domains in the pores of the porous particles from step (c) and adjacent the modifier material domains formed in the porous particles from step (c); Including, The method wherein the porous particle scaffold has a volume ratio of micropores to mesopores of from 90:10 to 0:

100.

44. 44. The method of claim 43, wherein the porous particles have any of the characteristics described for the porous particle scaffolds of claims 3 to 12.

45. The porous particles have a D in the range of 0.5 μm to 30 μm, or 1 μm to 25 μm, or 1 μm to 20 μm, or 2 μm to 25 μm, or 2 μm to 20 μm, or 2 μm to 18 μm, or 2 μm to 15 μm, or 2 μm to 12 μm, or 2.5 μm to 15 μm, or 2.5 μm to 12 μm, or 2 μm to 10 μm. ５０ 44. The method of claim 43, wherein the particle size is

46. 44. The method of claim 43, wherein the electroactive material deposited in steps (b) and (d) is independently selected from silicon, tin, germanium, aluminum, and mixtures and alloys thereof, or the electroactive material deposited in at least one of steps (b) and (d) is silicon.

47. 44. The method of claim 43, wherein the electroactive material deposited in each of steps (b) and (d) is the same electroactive material, or wherein the electroactive material deposited in each of steps (b) and (d) is silicon.

48. The precursor of the electroactive material in each of steps (b) and (d) independently comprises silane (SiH ４ ), disilane (Si ２ H ６ ), trisilane (Si ３ H ８ ), tetrasilane (Si ４ H １０ ), methylsilane, dimethylsilane, and chlorosilane.

49. 44. The method of claim 43, wherein steps (b) and (d) are independently carried out at a temperature in the range of from 300°C to 800°C, or from 350°C to 800°C, or from 380°C to 700°C, or from 380°C to 650°C, or from 380°C to 600°C, or from 380°C to 550°C, or from 380°C to 500°C, or from 400°C to 450°C, or from 450°C to 500°C.

50. 44. The method of claim 43, wherein step (b) and / or step (d) further comprises separating by-products from the particles.

51. 44. The method of claim 43, wherein step (c) further comprises contacting the intermediate particles from step (b) with a passivating agent.

52. 52. The method of claim 51 , wherein the passivating agent is selected from (i) an oxygen-containing gas, (ii) ammonia, (iii) a gas comprising ammonia and oxygen, and (iv) phosphine, or the passivating agent is ammonia.

53. The passivation agent is (i)R １ -CH=CH-R １ 、 ())) １ .≡.!R １ 、 (iii)O=CR １ R １ 、 (iv) HX-R ２ , and (v)HX-C(O)-R １ (Wherein, X is O, S, NR １ or PR １ indicates, Each R １ independently represent H or an unsubstituted or substituted aliphatic or aromatic hydrocarbyl group having 1 to 20 carbon atoms, or two R １ The group forms an unsubstituted or substituted ring structure containing 3 to 8 carbon atoms in the ring; R ２ represents an unsubstituted or substituted aliphatic or aromatic hydrocarbyl group having 1 to 20 carbon atoms, or R １ and R ２ together form an unsubstituted or substituted ring structure containing 3 to 8 carbon atoms in the ring; 52. The method of claim 51.

54. 52. The method of claim 51, wherein the passivating agent is selected from the group consisting of ethylene, propylene, 1-butene, butadiene, 1-pentene, 1,4-pentadiene, 1-hexene, 1-octene, styrene, divinylbenzene, acetylene, phenylacetylene, norbornene, norbornadiene, and bicyclo[2.2.2]oct-2-ene.

55. 44. The method of claim 43, wherein step (c) comprises contacting the intermediate particles from step (b) with a carbon-containing precursor at a temperature effective to cause deposition of a pyrolytic carbon material in the pores of the intermediate particles.

56. After step (d), the additional step of forming a plurality of modifier material domains in the pores of the porous particle and adjacent to the electroactive material domains; and the additional step of contacting the porous particle with a precursor of an electroactive material at a temperature effective to cause deposition of additional electroactive material domains in the pores of the porous particle and adjacent the modifier material domains; is repeated one or more times.

57. (e) forming a plurality of modifier material domains in the pores and / or on the exterior surface of the composite particles from step (d); 44. The method of claim 43, further comprising:

58. 58. The method of claim 57, wherein step (e) comprises contacting the surface of the composite particles from the last step (d) with a passivating agent, or wherein the passivating agent is as defined in any one of claims 52 to 54.

59. 58. The method of claim 57, wherein step (e) comprises combining the composite particles from step (d) with a pyrolytic carbon precursor and heating the pyrolytic carbon precursor to a temperature effective to cause deposition of a pyrolytic conductive carbon material within the pores and / or on the exterior surfaces of the composite particles.

60. The porous particles have a particle size distribution span (D ９０ -D １０ ) / D ５０ 44. The method of claim 43, wherein

61. The electroactive material deposited in each of steps (b) and (d) is silicon, and the mass ratio of silicon to porous particles in the composite particles is [0.5×P １ ~1.9 x P １ ]: 1, where P １ is cm ３ 44. The method of claim 43, wherein the total pore volume of the micropores and mesopores of the porous particle is a dimensionless quantity having a measure of the total pore volume of the micropores and mesopores of the porous particle expressed in units of 1 / g.

62. A composition comprising the particulate material of claim 1 and at least one other component.

63. 10. The particulate material of claim 1.

64. 64. A rechargeable metal-ion battery comprising the electrode of claim 63.

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