Manufacturing process of silicon-containing composite particles

Abstract

A process for manufacturing composite particles, wherein the process comprises the following steps: (a) providing a plurality of porous particles within a reactor, wherein the reactor has an outer wall defining an internal volume for accommodating the plurality of porous particles; (b) stirring the plurality of porous particles with a stirring member located in the internal volume, wherein the stirring member has one or more stirring surfaces, each stirring surface is a region of the stirring member that forms an angle of inclination with respect to a velocity vector during stirring, and wherein the plurality of porous particles are arranged such that as the stirring surface moves through the plurality of porous particles, the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall, wherein the outer wall is movable to induce stirring of the plurality of particles, and one or more stirring surfaces of the stirring member protrude from the inner surface of the movable outer wall; or wherein the stirring member forms a clearance between the stirring member and the inner surface of the outer wall, wherein the clearance is less than 10% of the internal dimensions of the reactor measured along the direction of the clearance; A step in which the mass of a plurality of porous particles contained in an internal volume during stirring varies according to the volume of the internal volume and is 500 kg m-3 or less, and varies according to the surface area of ​​one or more stirring surfaces and is 1000 kg m-2 or less, and the volume passing through the one or more stirring surfaces per second during stirring varies according to the mass of a plurality of porous particles contained in the internal volume, and the value is 0.001 to 0.1 m3s-1 kg-1; and (c) a step in which, while stirring the plurality of porous particles, the plurality of porous particles are contacted with a silicon precursor gas under conditions effective for depositing silicon within the pores of the porous particles, thereby providing a composite particle comprising a porous particle framework and elemental silicon present within the pores of the porous particle framework.

Description

Technology Field

[0001] The present invention relates to a process for manufacturing silicon-containing composite particles suitable for use as an anode active material in a rechargeable lithium-ion battery. Background Technology

[0002] A conventional lithium-ion battery (LIB) comprises an anode, a cathode, and a lithium-containing electrolyte. The anode generally comprises a metal current collector provided with a layer of electroactive material, wherein electroactive material refers to a material capable of inserting and releasing lithium ions during the charging and discharging of the battery. In this specification, the terms “cathode” and “anode” are used to mean that the anode becomes the negative electrode when the battery is connected to a load. When the LIB is charged, lithium ions move from the cathode to the anode through the electrolyte and are inserted into the electroactive material of the anode as intercalated lithium atoms. In this specification, the term “battery” refers to both a device comprising a single lithium-ion cell and a device comprising a plurality of connected lithium-ion cells.

[0003] LIBs were developed in the 1980s and 1990s and have since been widely applied to portable electronic devices. Recently, the development of electric or hybrid vehicles has significantly expanded new markets for LIBs, and the expansion of renewable energy sources has further increased the demand for on-grid energy storage, which can be met at least partially by LIB farms. Overall global LIB production is expected to increase from approximately 290 GWh in 2018 to over 2,000 GWh in 2028.

[0004] Along with the increase in total storage capacity, significant attention is being focused on improving the gravimetric and / or volumetric capacities of rechargeable metal-ion batteries to achieve the same energy storage capacity with less battery mass and / or battery volume. Conventional LIBs use graphite as the anode electroactive material. Graphite anodes can accommodate up to one lithium atom per six carbon atoms, giving them a theoretical maximum specific capacity of 372 mAh / g in lithium-ion batteries, although the actual capacity is somewhat lower (approximately 340 to 360 mAh / g).

[0005] Silicon is a promising material that can replace graphite because of its very large lithium storage capacity (e.g., Insertion Electrode Materials for Rechargeable Lithium Batteries, Winter, M. et al . See Adv. Mater. 1998, 10, No. 10). Lithium-ion battery (Li 15 The theoretical maximum specific capacity of silicon (based on Si4) is approximately 3,600 mAh / g. However, intercalating lithium into bulk silicon can cause the silicon material to expand up to 400% of its original volume, potentially leading to battery failure. Repeated charge-discharge cycles induce significant mechanical stress, resulting in fracturing and delamination of the silicon. When a solid electrolyte interphase (SEI) layer forms on the silicon surface, the electrolyte is consumed; the newly exposed silicon surface at the fracture interface triggers further degradation of the electrolyte, which consequently increases the thickness of the SEI layer and leads to the irreversible consumption of lithium. These failure mechanisms accumulate, resulting in unacceptable electrochemical capacity loss over continuous charge-discharge cycles.

[0006] The applicant has previously reported the development of a group of electroactive materials having a composite structure in which an electroactive material, such as silicon, is deposited within a pore network of a highly porous conductive particulate material, e.g., a porous carbon material (see WO 2020 / 095067 and WO 2020 / 128495). The silicon contained in these materials is finely dispersed, and the size of individual silicon structures is approximately less than a few nanometers, so stress and strain are minimized during charging and discharging. Since the silicon is confined within the pore volume of the porous material, the exposure of the silicon surface to the electrolyte is minimized, effectively limiting the degree of SEI formation. As a result, these materials exhibit excellent reversible capacity retention over multiple charge-discharge cycles.

[0007] The materials described in WO 2020 / 095067 and WO 2020 / 128495 were synthesized by chemical vapor infiltration (CVI) in various reactor systems (static, rotary, and fluidized bed reactors). More recently, as described in WO 2023 / 117047, close-clearance stirred-bed reactors have been developed to overcome the problems arising in each type of reactor system that lead to non-uniformity of the final product. The problem with the type of close-clearance stirred-bed reactor disclosed in WO 2023 / 117047 is that dense regions of particles moving in the stirring direction and tangentially along the outer wall of the reactor tend to form. Consequently, these close-clearance stirred-bed reactors tend to have poor aeration of the particle layer and poor vertical circulation of particles within the reactor. This phenomenon results in non-uniformity of the final composite particles.

[0008] Therefore, an improved manufacturing process for composite particles using a stirred-bed reactor capable of overcoming the aforementioned problems is required.

[0009] According to a first aspect of the present invention, a process for treating particles is provided, the process comprises the following steps: (a) providing a plurality of porous particles in a reactor, wherein the reactor has an outer wall defining an internal volume for accommodating the plurality of porous particles; (b) agitating the plurality of porous particles with a stirring member located in the internal volume, wherein the stirring member has one or more stirring surfaces, each stirring surface is a region of the stirring member that forms an angle of inclination with respect to a velocity vector during stirring, and wherein the plurality of porous particles are arranged such that as the stirring surface moves through the plurality of porous particles, the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall, wherein the outer wall is movable to induce stirring of the plurality of particles, and one or more stirring surfaces of the stirring member protrude from the inner surface of the movable outer wall; Or the stirring member forms a clearance between the stirring member and the inner surface of the outer wall, said clearance being less than 10% of the internal dimensions of the reactor measured along the clearance direction; and during stirring, the mass of a plurality of porous particles contained in the internal volume varies with the volume of the internal volume and is 500 kg m⁻² -3 Less than or equal to, and varies depending on the surface area of ​​one or more stirring surfaces, 1000 kg m² -2 The above is as follows, and the volume passing through the one or more stirring surfaces per second during stirring depends on the mass of a plurality of porous particles contained in the internal volume, and the value is 0.001 to 0.1 m 3 s -1 kg -1 (c) a step of bringing the plurality of porous particles and the gas into contact under conditions effective for inducing a reaction between the plurality of porous particles and the gas while stirring the plurality of porous particles.

[0010] The inventors have recognized that there are various phenomena that reduce the operating efficiency of known narrow-gap stirred-bed reactors, and that these phenomena generally reduce the aeration of the stirred particle layer. During operation, such a reactor can be considered to comprise a concentrated phase, which is a region where the concentration of porous particles is relatively high and the concentration of gas is relatively low, and a dilute phase, which is a region where the concentration of porous particles is relatively low and the concentration of gas is relatively high. The goal of a stirred-bed reactor, namely good aeration of the particle layer, can be considered in terms of the transition between these phases within the reactor, and to achieve good aeration, it is desirable to minimize the difference between these phases and ensure a gradual transition between them within the reactor.

[0011] The first issue affecting this objective is the loading amount of porous particles relative to the volume of the reactor. A relatively high loading amount implies that there is almost no space for the particles to move during the stirring process. Therefore, if the loading amount is high, while some areas of the particle layer may be aerated through the stirring process, a significant portion of the particle layer may remain in a very concentrated state without being sufficiently aerated. The inventors argue that in order to ensure uniform aeration of the particle layer, the mass of multiple porous particles contained in the internal volume is such that the internal volume 1m³ 3 It was discovered that it must be 500kg or less per day.

[0012] The second issue concerns the relationship between the charge amount of porous particles and the surface area of ​​the stirring element relative to the reactor volume. As previously discussed, if the charge amount is relatively small, sufficient space is secured within the reactor, allowing for the proper aeration of the entire particle layer. However, to effectively induce aeration of the particle layer using the stirring element, the surface area of ​​the stirring surface must be sufficient relative to the charge amount of porous particles. The surface area of ​​the stirring surface influences the velocity at which the stirrer displaces particles to move them from the concentrated phase to the dilute phase as it passes through the particle layer. As the surface area of ​​the stirring surface decreases for a given amount of particles, it becomes necessary to move the stirring surface faster within the particle layer to achieve the same amount of particle layer aeration. However, as mentioned earlier, if the stirring speed becomes excessively fast, there is a tendency for dense regions to form along the outer wall of the reactor, where particles move in the stirring direction and tangentially. Therefore, to ensure sufficient particle agitation even at low speeds, the mass of multiple porous particles contained within the internal volume must also be determined by the surface area of ​​one or more stirring surfaces; specifically, a stirring surface area of ​​1 m² -2 It was found that it should not exceed 1,000 kg per day.

[0013] Finally, an appropriate particle loading amount must be set according to the reactor volume and the surface area of ​​the stirrer so that a sufficient volume of the reactor's internal volume is swept out by the stirring surface, and the stirring speed must be within an appropriate range capable of supplying sufficient air to the particle layer so that the particle layer is not compressed along the outer wall or its movement is not restricted mostly to the stirring direction. At the above loading amount, when one or more stirring surfaces pass through a volume per second that varies depending on the mass of multiple porous particles contained in the internal volume during stirring, i.e., 0.001 to 0.1 m 3 s -1 kg -1It was observed that the aeration of the particle layer was good when passing through the inter-volume range. In other words, to properly aerate the particle layer, the stirring surface must sweep a certain volume per second per 1 kg of particle. Therefore, this parameter specifies the total volume inside the reactor through which at least one stirring surface passes, depending on the mass of the particles within the reactor and the stirring frequency. An example of the calculation for this is provided in the detailed example below.

[0014] In other words, this arrangement defines an operating area that not only improves heat and mass transfer but also prevents excessive charging of the reactor volume containing multiple porous particles, thereby enabling proper aeration and preventing the formation of very dense regions, and also provides an optimal operating range that prevents the possibility of entrainment of porous particles due to gas flow passing through the reactor. This arrangement also provides an operating area that provides a sufficient surface area of ​​stirring surfaces so that the concentration difference of porous particles is relatively small. If this area is too narrow, regions where the dense and dilute phases are separated are created due to the aggregation of porous particles, or even regions where the powder does not move at all may occur because momentum is not effectively transferred from the aerated region. On the other hand, if one or more stirring surfaces passing through a certain volume per second while stirring the mass of multiple porous particles contained in the internal volume are too excessive, this process may induce the particle layer to be compressed along the outer wall, thereby reducing heat transfer from the reactor wall or limiting movement mostly to only the stirring direction.

[0015] As previously explained, the present process utilizes a stirring member having one or more stirring surfaces, wherein the stirring surface is a surface of the stirring member that forms an angle of inclination with respect to the velocity vector during stirring, and is positioned so that as the stirring surface moves through a plurality of porous particles, the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall. Therefore, the stirring surface here refers to the surface of the stirring member facing forward, that is, the surface that at least partially faces the direction of movement during stirring. For example, it will be understood that the stirring surface may have an opposite surface, that is, a surface facing backward; however, since this surface does not face the stirring direction, it is not positioned so that the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall during stirring. Therefore, this surface is not considered part of the stirring surface, and accordingly, as described above, the area corresponding to it is not considered when determining the particle loading amount. It will be understood that there may be other parts of the stirring member that do not form an angle of inclination with respect to the velocity vector during stirring. Finally, it should be noted that the stirring surface can be positioned to induce particle movement along the outer wall or away from the outer wall, and that both directions tend to move particles toward the rarefied phase of the reactor. A surface forming an angle around an axis perpendicular to the outer wall induces particles to move along the outer wall. A surface forming an angle around an axis parallel to the outer wall and perpendicular to the velocity vector will push particles away from the outer wall, for example, if the leading edge is closer to the outer wall than the trailing edge. The stirring surface may also form an angle having components for both of these directions to move particles along the outer wall while simultaneously pushing them away from the outer wall.

[0016] The present invention relates to a so-called narrow gap stirred reactor. This includes both a reactor in which the stirring member is located at a relatively small distance from the outer wall of the reactor and a reactor in which the stirring surface of the stirring member protrudes from the inner surface of the movable outer wall (i.e., the gap is zero), but the former is more preferred. As previously mentioned, a small gap means a gap of less than 10% of the internal dimensions of the reactor measured along the gap direction. This gap direction is generally perpendicular to the velocity vector of the stirring member, and generally perpendicular to the axis of rotation when the stirring member rotates about an axis. It will be understood that the gap referred to here means the smallest gap between the stirring member and the outer wall, and that other parts of the stirring member may have a different gap from the outer wall. Preferably, the stirring member is provided to have a narrow gap (i.e., less than 10% of the internal dimensions of the reactor) with the outer wall along a direction perpendicular to the velocity vector of the stirring member, over at least 30%, preferably at least 40%, more preferably at least 50%, more preferably at least 60%, and most preferably at least 70% of the length of the reactor wall.

[0017] The porous particles used in this process may be of various types. The porous particles may contain open pores and / or closed pores. The pores of the porous particles may account for 10% to 95% of the particle volume. The porous particles generally include porous carbon particles, but may also include porous particles comprising silicon carbide, silica, alumina, titania, zirconia, metal nitrides (e.g., nitrides of Si, Al, Ti, etc.), mixed metal oxide nitrides (e.g., SiAlON), mixed metal oxides of Si, Al, Ti, etc., and metal oxide carbides, etc.

[0018] The above process is generally a process for manufacturing composite particles, wherein step (c) comprises contacting a plurality of porous particles with a gas under conditions effective for depositing silicon within the pores of the porous particles while stirring the plurality of porous particles. Preferably, the above process is a process for manufacturing composite particles, wherein step (c) comprises contacting a plurality of porous particles with a silicon precursor gas under conditions effective for depositing silicon within the pores of the porous particles while stirring the plurality of porous particles, thereby providing composite particles comprising a porous particle framework and elemental silicon present within the pores of the porous particle framework. Such a process forms composite particles of the type described in WO 2020 / 095067 and WO 2020 / 128495, which have been found to be particularly useful for forming electrodes of rechargeable metal-ion batteries. The resulting composite particles may remain porous with open and / or closed pores remaining, or the pores may be filled to a substantial extent by a deposition process. The porosity of the composite particles may be 0.5% to 80% of the particle volume (including open and closed pore volumes), but as material is deposited in the pores, it will more generally have a value closer to the lower limit of this range, and generally 5% to 60%.

[0019] While deposition using a silicon precursor gas is preferred, this process can also be applied to other solid-gas heterogeneous reactions in which multiple porous particles are brought into contact with a gas to induce a reaction between the particles and the gas. Other suitable gases include those with the general formula MX₀. n It includes a metal halide having, where M can be Al, Zn, Ti, Mn, Co, Ni, etc., and X is preferably Cl but can also be F or Br. MX nIn this case, n is an integer determined by the oxidation state of M. Other suitable gases include organometallics such as metal alkoxides and metal acetylacetonates, in which case the metal may be Al, Zn, Ti, Mn, Co, Ni, etc. Additionally, reactive gases such as ammonia and hydrogen sulfide may also be used to generate nitrides and sulfides, for example, within the pores. Likewise, boron-containing gases such as diborane and trimethylborate may be used. Another possible coating process involves a coating process that forms a TiO2 or Al2O3 layer, including an ALD-type reaction, in which case the temperature of step (c) will generally be 100 to 700°C.

[0020] The present method may include not only a deposition process but also other reaction processes, such as a passivation process, which includes a passivation process occurring during the manufacture of the type of composite particles discussed above. For example, such processes may include a passivation process after silicon deposition, in which case the particles are processed within the disclosed parameter ranges in both the deposition process and the passivation process. The advantages described herein regarding the aeration of the particle layer and the mixing of the dense and dilute phases provide the same advantages in the passivation process, for example, by enabling the particles to be passivated more uniformly.

[0021] The passivation process may involve passivating particles in a low-oxygen environment with an oxygen concentration of less than 10 volume%, or passivating composite particles using an inert gas such as nitrogen. A gas mixture with a low oxygen concentration may also be used. To be more specific, the gas used in step (c) of the passivation process may be an oxygen-containing gas (e.g., oxygen, air, steam, etc., preferably at a temperature in the range of 15°C to 500°C), carbon dioxide (preferably at a temperature in the range of 15°C to 500°C), ammonia, phosphine, hydrocarbons, e.g., alkenes, alkynes, or carbonyl functional groups, preferably terminal alkenes, terminal alkynes, aldehydes, or ketone groups (preferably at a temperature in the range of 15°C to 700°C), ethylene, propylene, 1-butene, butadiene, 1-pentene, 1,4-pentadiene, 1-hexene, 1-octene, styrene, divinylbenzene, acetylene, phenylacetylene, norbornene, norbornene, and bicyclo[2.2.2]oct-2-ene. A mixture of passivation gases may also be used. If this passivation step is performed after the silicon deposition process, it may be performed in a stirred reactor with stirring at the same parameters as discussed herein. Passivating the intermediate particles can remove highly reactive Si-H bonds. The particles may be cooled, or optionally, cooled together with the passivation step. Cooling may be performed to less than 100°C, less than 50°C, or to ambient temperature, e.g., 20°C.

[0022] Another example is a process for depositing a conductive carbon coating on particles using a carbon precursor gas. This may involve the thermal decomposition of a volatile carbon-containing gas (e.g., ethylene, acetylene, propane, propylene, ethane and other alkanes, alkenes or alkynes, C2 to C10 hydrocarbons, cycloalkanes, cycloalkenes, arenes, polycyclic hydrocarbons and their derivatives) on the surface of the particle material. The temperature of step (c) will generally be between 350°C and 700°C. If this process is performed while stirring the particles according to the parameter ranges disclosed herein, the same benefits of aeration and phase mixing can be obtained in this process as well.

[0023] Another suitable process is a functionalization process, in which a functional group precursor is brought into contact with porous particles and then evaporated to allow a reaction to occur that provides surface functional groups. The precursor includes a silane having an epoxy terminal functional group (e.g., an amino- or glycidyl-alkyl-trialkoxy-silane, where the alkyl group may be C1 to C6 and the alkoxy group may be methoxy or ethoxy); an imide surface functional group for silicon surfaces such as poly(ether imide) or PEI; and silicon surface functionalization of a composite material using an electrolyte.

[0024] In addition, this process may be a process of doping in the gas phase or adding dopants to pre-treat initial porous particles or to treat composite particles after deposition. Suitable dopants include nitrogen, phosphorus, sulfur, and boron, which can significantly improve electrical conductivity and improve the structural stability of silicon-carbon composite particles; fluorine, which can form a stable solid electrolyte interface (SEI); and transition metals such as Ti, Co, Ni, Mn, Mo, and W, which can improve conductivity and stabilize the structure of composite particles.

[0025] In general, it is desirable to maintain a low maximum charging limit for multiple porous particles with respect to both the reactor volume and the stirrer surface area. Lowering the maximum charging limit provides more space for the particle layer to move and increases the ratio of the stirrer area to the particle layer, thereby achieving additional improvements. Therefore, preferably, the mass of multiple porous particles contained in the internal volume during stirring depends on the volume of the internal volume, and 400 kgm -3 Below, preferably 300 kgm -3 Below, more preferably 250 kgm -3 It is as follows. Likewise, preferably, the mass of a plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​one or more stirring surfaces, and 750 kg m² -2 Below, preferably 500 kg m -2 Below, more preferably 400 kg m -2 Below, most preferably 300 kg m -2 The following applies. A particularly desirable combination is 400 kg m³ relative to the reactor volume. -3 Mass and 1000 kg m² relative to the stirrer area -2 Mass less than or equal to 400 kg m³ relative to reactor volume -3 The following mass and 750 kg m² relative to the stirrer area -2 Mass less than or equal to 400 kg m³ relative to reactor volume -3 Mass and 300 kg m² relative to the stirrer area -2 Mass less than or equal to 300 kg m³ relative to reactor volume -3 The following mass and 750 kg m² relative to the stirrer area -2 Mass less than or equal to 300 kg m³ relative to reactor volume -3 Mass and 500 kg m² relative to the stirrer area -2 It includes the following mass.

[0026] While the maximum charging limit of porous particles was discussed above in relation to the reactor volume and the surface area of ​​the stirrer, it is also desirable to set a minimum charging limit. Generally, reducing the charging amount below the upper charging limit mentioned above further improves air permeability, but efficiency gradually decreases, and very low charging amounts are generally inefficient. Therefore, it is desirable that the mass of multiple porous particles contained in the internal volume during stirring varies according to the volume of the internal volume, and 15 kgm -3 Above, preferably 50 kgm -3 Ideally, 100 kgm -3 That is all. Likewise, it is preferable that the mass of a plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​one or more stirring surfaces, and 1 kg m² -2 Ideally, 3 kg m² -2 Ideally, 5 kg m² -2 Ideally, 10 kg m² -2 Ideally, 15 kg m² is most preferable. -2 That is all.

[0027] Preferably, the mass of a plurality of porous particles contained in the internal volume during stirring is 15 kg m³ of the volume of the internal volume. -3 up to 500 kg m -3 and preferably 50 kg m -3 up to 500 kg m -3 is, and more preferably 50 kg m -3 Up to 400 kg m -3 and, more preferably 100 kg m -3 Up to 400 kg m -3 is, and more preferably 100 kg m -3 Up to 300 kg m -3 and, most preferably 100 kg m -3 Up to 200 kg m -3is. Preferably, the mass of a plurality of porous particles contained in the internal volume during stirring is 1 kg m² relative to the surface area of ​​one or more stirring surfaces. -2 Up to 750 kg m -2 and preferably 3 kg m -2 up to 500 kg m -2 is, and more preferably 10 kg m -2 Up to 400 kg m -2 and, more preferably 30 kg m -2 Up to 300 kg m -2 is, and more preferably 40 kg m -2 Up to 200 kg m -2 am.

[0028] Along with the above loading amount, the tap density of the porous particles is at least 0.25 g / cm³ 3 , 1.5 g / cm 3 It may be less than or equal to. Preferably, the tap density of the porous particles is at least 0.3 g / cm³. 3 , at least 0.35 g / cm³ 3 , at least 0.4 g / cm³ 3 , or at least 0.5 g / cm³ 3 is. Preferably, the tap density of the porous particles is 1 g / cm³. 3 Less than or equal to 0.8 g / cm³ 3 Less than or equal to 0.7 g / cm³ 3 It is as follows.

[0029] Tap density is measured according to ISO 3953:2011 and ISO 787-11:1981 (measurement of volume and apparent density after tapping), and is measured using Quantachrome™ Autotap, for example, with a minimum sample volume of 8 ml or more. The instrument's drop height is 3 mm, and the instrument's tapping frequency is fixed at 250 to 265 taps per minute. The sample is tapped at least 5,000 times. If the sample volume is still observed to change after 5,000 taps, additional tapping is performed in increments of 1,250 until no further volume change is observed.

[0030] Along with the above loading amount, the Hausner ratio of the porous particles is at most 4.0, preferably at most 3.0, more preferably at most 2.0. The Hausner ratio may be at least 1.2, preferably at least 1.4, preferably at least 1.6, and preferably at least 1.8. Preferably, the Hausner ratio of the porous particles may be within the range of 1.2 to 4.0, preferably 1.2 to 3.0, preferably 1.2 to 2.0, preferably 1.2 to 1.8, preferably 1.2 to 1.6, and most preferably 1.2 to 1.4. Hausner ratio, Is It is calculated as. Parameter is the tapped bulk density of multiple porous particles measured in the manner described above. Parameter ε is the freely settled bulk density of multiple porous particles, that is, the bulk density measured before tapping during the tap density measurement process described above. Since particles with a high house width tend to have high cohesiveness and do not mix well, it is more desirable to charge particles with a relatively low house width within the above range. As cohesiveness varies with house width, it is also desirable to adjust the stirring speed according to the house width of the particles. In particular, for porous particles with a house width of 1.4 or less, preferably 1.2 to 1.4, the volume passing per second through one or more stirring surfaces during stirring, depending on the mass of multiple particles contained in the internal volume, is 0.001 to 0.005 m³ 3 s -1 kg -1 This may be the case, and it has been found to provide particularly excellent air permeability to the particle layer. On the other hand, for porous particles with a house width greater than 1.4, the volume passing per second through one or more stirring surfaces during stirring, depending on the mass of multiple particles contained in the internal volume, is 0.005 to 0.1 m³ 3 s -1 kg -1 Therefore, a high stirring speed complements high cohesiveness.

[0031] Likewise, to further improve the balance between the displacement of the particle layer to induce aeration and the tendency to induce tangential movement and consolidation of particles occurring at high velocities, preferably one or more stirring surfaces are 0.002 to 0.08 m during stirring. 3 s -1 kg -1 , preferably 0.003 to 0.06 m 3 s -1 kg -1 , more preferably 0.004 to 0.04 m 3 s -1 kg -1 , most preferably 0.005 to 0.02 m3 s -1 kg -1 It passes through a volume per second that varies depending on the mass of multiple porous particles contained in the internal volume.

[0032] A particularly desirable combination of the mass of multiple porous particles contained in the internal volume during stirring and the volume swept away by the stirring surface is as follows: mass relative to reactor volume is 400 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 750 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume during stirring, is 0.002 to 0.08 m³ 3　 s -1 kg -1 A combination of; or a mass relative to reactor volume of 400 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 500 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume during stirring, is 0.002 to 0.08 m³ 3　 s -1 kg -1 A combination of; or a mass relative to reactor volume of 400 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 750 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume during stirring, is 0.003 to 0.06 m³ 3　 s -1 kg -1 A combination of; or a mass relative to reactor volume of 400 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 500 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume, is 0.003 to 0.06 m³ 3　 s-1 kg -1 A combination of; or a mass relative to reactor volume of 400 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 500 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume, is 0.004 to 0.04 m³ 3　 s -1 kg -1 A combination of; or a mass relative to reactor volume of 300 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 400 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume, is 0.004 to 0.04 m³ 3　 s -1 kg -1 A combination of; or a mass relative to reactor volume of 250 kg m³ -3 It is less than or equal to, and the mass relative to the stirrer area is 300 kg m² -2 The volume passing per second through one or more stirring surfaces, which varies depending on the mass of multiple porous particles contained in the internal volume, is 0.005 to 0.02 m³ 3　 s -1 kg -1 A combination of. Each of these preferred combinations is also preferably further equipped with a stirring member that moves through 5% to 90%, preferably 10% to 80%, more preferably 20% to 70%, and most preferably 30% to 60% of the internal volume during stirring.

[0033] The geometric shape of the stirring surface can be varied within the parameter range mentioned above to influence the arrangement of the particle layer. In some embodiments, the stirring member may be configured such that one or more stirring surfaces extend across the entire height of the particle layer prior to stirring, and in some cases, extend beyond the entire height of the particle layer. In this way, the stirring member may pass through a space corresponding to the entire height of the particle layer during stirring. In other embodiments, the stirring member may be configured such that one or more stirring surfaces pass through only a portion of the height of the particle layer prior to stirring.

[0034] In some embodiments, the stirring member forms a gap between the stirring member and the inner surface of the outer wall, said gap being less than 5%, preferably less than 2%, and most preferably less than 1% of the internal dimensions of the reactor measured along the gap direction. As previously mentioned, such a gap may be provided along a direction perpendicular to the velocity vector of the stirring member over at least 30%, preferably at least 40%, more preferably at least 50%, more preferably at least 60%, and most preferably at least 70% of the length of the reactor wall. Generally, a smaller gap is preferable because it prevents particles from clumping on the outer wall of the reactor. In a particularly preferred embodiment, the gap of the reactor is selected according to the particle size. The smaller the particles, the greater the tendency to clump on the outer wall, and also, more particles are contained in the portion of the outer wall built up to a certain thickness. Therefore, preferably, the gap between the stirring member and the inner surface of the outer wall depends on the size of a plurality of porous particles provided within the reactor, D 50 For porous particles with a particle diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10% of the internal dimensions of the reactor measured along the gap direction, and D 50For porous particles with a particle diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 3% of the internal dimensions of the reactor measured along the gap direction, or D 50 For porous particles with a particle diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 2% of the internal dimensions of the reactor measured along the gap direction. More preferably, D 98 For porous particles with a particle diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10% of the internal dimensions of the reactor measured along the gap direction, and D 98 For porous particles with a particle diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 3% of the internal dimensions of the reactor measured along the gap direction, or D 98 For porous particles with a particle diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 2% of the internal dimensions of the reactor measured along the gap direction. Preferably, D 50 or D 98These gaps based on particle diameter are provided with multiple porous particles having a span of less than 5, preferably less than 3, and preferably less than 2. The span is discussed in more detail below. For porous particles with a particle diameter of less than 30 μm, a gap of less than 3% is recommended to prevent uneven penetration and the formation of a "crust" around the reactor wall, as particles of this size or smaller have high cohesiveness and a significant number of particles adhere to the reactor wall, thereby hindering heat transfer and causing a larger temperature difference across the entire layer of porous particles adhering to the wall, which consequently causes very severe temperature deviations. As previously mentioned, the importance of the gap applies not only to porous particles with a particle diameter of less than 30 μm but also to porous particles with a particle diameter of up to 200 μm. These particles may behave differently from particles with a particle diameter of less than 30 μm in relation to the Geldart type, which will be discussed in more detail below, but still require proper aeration, provided that the gap can be allowed up to the higher value discussed above.

[0035] As used herein, the term “particle diameter” means equivalent spherical diameter (esd), that is, the diameter of a sphere having the same volume as a given particle, wherein the particle volume is understood to include the volume of intra-particle pores. As used herein, “D 50 " and "D 50 The term "particle diameter" refers to the volume-based median particle diameter, that is, the diameter of which 50% of the particles, based on the volume of the particle population, have a diameter smaller than that. More generally, "D X " and "D X The term "particle diameter" refers to the particle diameter at which X% of the particle population has a diameter smaller than that of the population.

[0036] Particle diameter and particle size distribution can be measured by standard laser diffraction techniques in accordance with ISO 13320:2020. Laser diffraction is based on the principle that particles scatter light at angles that vary with particle size, and that multiple particles will come together to create a scattered light pattern defined by intensity and angle; this pattern can be associated with particle size distribution. Various laser diffraction instruments are commercially available for the rapid and reliable measurement of particle size distribution. Unless otherwise noted, particle size distribution measurements specified or reported herein are from Malvern Instruments TM The existing Malvern Mastersizer provided by TM This is a value measured by a 3000 particle size analyzer. Malvern Mastersizer TM The 3000 particle size analyzer operates by transmitting a helium-neon gas laser beam through a transparent cell in which particles of interest are suspended in an aqueous solution. The light beam colliding with the particles is scattered at an angle inversely proportional to the particle size, and a photodetector array measures the light intensity at several predetermined angles. The intensity measured at various angles is then processed by a computer using the standard theoretical principle to determine the particle size distribution. The laser diffraction values ​​reported herein are for the surfactant SPAN TM This value is obtained by wet-dispersing particles in 2-propanol to which 5 volume% of -40 (sorbitan monopalmitate) was added. The refractive index of the particles is set to 2.68 for porous particles and 3.50 for composite particles, and the dispersant index of the dispersion medium is set to 1.378. The particle size distribution is calculated using a Mie scattering model.

[0037] The above gap value is expressed as a percentage of the reactor size. However, it may be more desirable to ensure a specific absolute gap size. Preferably, the gap between the stirring member and the inner surface of the outer wall is 5 cm or less, preferably 2 cm or less, more preferably 1 cm or less, more preferably 5 mm or less, and most preferably 2 mm or less. Generally, due to differences in tolerances based on scale, a reactor with a smaller internal volume may maintain a smaller gap during stirring compared to a large reactor. Preferably, the gap between the stirring member and the inner surface of the outer wall is less than or equal to the smaller of 10% or 5 cm, more preferably less than or equal to the smaller of 5% or 2 cm, and most preferably less than or equal to the smaller of 2% or 1 cm.

[0038] It may be advantageous to select the particle size based on the absolute gap between the stirring member and the inner surface of the outer wall. Preferably, the gap between the stirring member and the inner surface of the outer wall varies depending on the size of the plurality of particles provided in the reactor, D 50 For particles with a diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 150 mm, and D 50 For particles with a diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 50 mm, or D 50 For particles with a diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10 mm. Preferably, D 98 For porous particles with a particle diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 150 mm, and D 98 For porous particles with a particle diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 50 mm, or D 98For porous particles with a particle diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10 mm. Alternatively, for a plurality of porous particles, D is 0.01% or more of the nearest gap between the stirring member and the inner surface of the outer wall. 50 or D 98 It can have a particle diameter, and more preferably D 50 or D 98 The particle diameter may be at least 0.05% of the gap between the stirring member and the inner surface of the outer wall, more preferably at least 0.1%, more preferably at least 0.5%, more preferably at least 1%, and most preferably at least 2%. This limits the number of particles that can enter between the stirring member and the inner surface of the outer wall, thereby preventing particles from accumulating on the outer wall. In other words, preferably, D 50 or D 98 These gaps based on particle diameter are provided with a plurality of porous particles having a span of less than 5, preferably less than 3, preferably less than 2.

[0039] The present invention is particularly D 50 It is useful for porous particles with a particle diameter of less than 200 μm, preferably less than 100 μm, and more preferably less than 50 μm. A plurality of porous particles are D 50 The particle diameter may be in the range of 0.5 μm to 200 μm, preferably in the range of 1 μm to 30 μm, and more preferably in the range of 2 μm to 10 μm. Alternatively or additionally, the porous particles may have a D1 particle diameter of at least 0.1 μm, preferably at least 0.5 μm, more preferably at least 1 μm, and more preferably at least 1.5 μm. Alternatively or additionally, the porous particles D 10The particle diameter may be at least 0.2 μm, preferably at least 0.5 μm, more preferably at least 1 μm, more preferably at least 1.5 μm, more preferably at least 2 μm, and more preferably at least 3 μm. The porous particles are alternatively or additionally D 90 The particle diameter may be 250 μm or less, preferably 150 μm or less, more preferably 100 μm or less, more preferably 50 μm or less, and more preferably 30 μm or less. The porous particles are alternatively or additionally D 98 The particle diameter may be 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, more preferably 50 μm or less, and more preferably 30 μm or less. Particles of this size have particularly strong cohesive forces and a high tendency to clump together, but can be sufficiently aerated when stirred in the manner described. Using a process including a well-aerated stirred-bed reactor as presented herein is particularly useful for preventing particle aggregation.

[0040] The present invention also relates to the span of a plurality of porous particles ( It is particularly applicable when (defined as) is 5 or less, preferably 4 or less, more preferably 3 or less, more preferably 2 or less, and more preferably 1.5 or less. In particular, a plurality of porous particles with low span have relatively uniform particle diameters. This ensures that the particle layer responds relatively uniformly to stirring in the manner described herein.

[0041] The present invention can also be used for porous particles in which a plurality of particles preferably exhibit positive skewness in a volume-based particle diameter distribution. Preferably, D 50 The diameter is smaller than the volume-based average particle diameter. Preferably, the skewness of the porous particle diameter distribution (Malvern Mastersizer TM3000 (measured by an analyzer) is 4 or less, 3 or less, 2 or less, or 1.5 or less. Preferably, the skewness is at least 0.2, at least 0.3, or at least 0.4. The particle diameter distribution of the porous particles may be monomodal, bimodal, or multimodal.

[0042] This process is based on the literature (Reference: Geldart. "Types of gas fluidization." Powder technology It can be advantageously used to process porous particles classified as Geldart Group A or Geldart Group C as defined in 7.5 (1973): 285-292). Group C particles are characterized by strong cohesiveness, making them difficult to fluidize, which means that stirring is particularly important. However, this process is also advantageous when processing Group A particles. Although these particles are characterized by being aerated, this process enables processing of this type of particle without using the relatively high gas flow rates required for fluidization.

[0043] In some embodiments, a plurality of porous particles belong to group A of Geldarts, for example, D 50 The particle diameter is within the range of 30 μm to 200 μm. Since Geldart Group A particles require relatively little energy for aeration, one or more stirring surfaces are 0.001 to 0.005 m during stirring. 3 s -1 kg -1The volume per second can pass through. More preferably, since the Geldart Group A particles move more freely within the reactor, in this embodiment, the total stirring volume, expressed as a percentage of the total internal volume, can be lower, which helps to reduce the weight of the stirrer and the torque required during stirring. In particular, it is desirable that this be within the range of 5% to 85%, preferably 10% to 80%, preferably 20% to 80%, preferably 20% to 70%, preferably 30% to 70%, preferably 30% to 60%, and preferably 30% to 50%. In another embodiment, a plurality of porous particles belong to Geldart Group C, for example, D 50 The particle diameter is less than 30 μm. Since Geldart Group C particles require relatively more energy for aeration, one or more stirring surfaces are 0.005 to 0.1 m during stirring. 3 s -1 kg -1 It can pass through a volume per second. Since this type of particle is less free of particle movement, dead spots are prone to occur; therefore, in this embodiment, the total stirring volume, expressed as a percentage of the total internal volume, must be larger. In particular, it is desirable that this be within the range of 20% to 90%, preferably 30% to 90%, preferably 30% to 85%, preferably 40% to 80%, and preferably 60% to 80%.

[0044] Whether the particles belong to Geldart Group A and the above-mentioned preferred low stirring speed is used, or belong to Geldart Group C and the above-mentioned preferred high stirring speed is used, in both cases, the preferred charging limits described in detail above can be observed. However, it is particularly desirable to adjust the charging amount of particles differently for each particle of the Geldart group. In particular, in some embodiments, a plurality of porous particles belong to Geldart Group A, and the mass of a plurality of porous particles contained in the internal volume during stirring depends on the volume of the internal volume, and the value is 100 kg m⁻³ -3 up to 500 kg m -3 , preferably 150 kg m -3 up to 500 kg m -3 , preferably 200 kg m -3 up to 500 kg m -3 , preferably 250 kg m -3 up to 500 kg m -3 and optionally, one or more stirring surfaces are 0.001 to 0.005 m during stirring 3 s -1 kg -1 It can pass through a volume per second. Likewise, alternatively or additionally, in some embodiments, a plurality of porous particles belong to Geldart Group A, and the mass of a plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​one or more stirring surfaces, and the value is 200 kg m² -2 up to 1000 kg m -2 , preferably 300 kg m -2 up to 1000 kg m -2 , preferably 400 kg m -2 up to 1000 kg m -2 and optionally, one or more stirring surfaces are 0.001 to 0.005 m during stirring 3 s -1 kg -1It can pass through a volume per second. On the other hand, in another embodiment, a plurality of porous particles belong to Geldart Group C, and the mass of a plurality of porous particles contained in the internal volume during stirring depends on the volume of the internal volume, and the value is 300 kg m³ -3 Less than, preferably 200 kg m² -3 Less than, preferably 150 kg m² -3 Less than, preferably 100 kg m² -3 Less than, and optionally one or more stirring surfaces are 0.005 to 0.1 m during stirring 3 s -1 kg -1 It can pass through a volume per second. Likewise, alternatively or additionally, in some embodiments, a plurality of porous particles belong to Geldart Group C, and the mass of a plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​one or more stirring surfaces, and the value is 100 kg m² -2 Less than, preferably 80 kg m² -2 Less than, preferably 50 kg m -2 Less than, and optionally one or more stirring surfaces are 0.005 to 0.1 m during stirring 3 s -1 kg -1It can pass through a volume per second. The reasons why the above combinations are desirable are as follows. When the charge mass of particles is relatively large relative to the reactor volume, it is likely that a larger stirrer area and a faster stirrer speed are required to agitate the volume required per second per kg of particles. As previously mentioned, Geldart Group C particles tend to require higher stirring speeds due to their high cohesiveness; this means that if the charge mass of Geldart Group C particles is large, an excessively high stirring speed is required, which can lead to negative consequences due to high stirring speeds as discussed in this specification. Therefore, when using Geldart Group C particles, lowering the charge amount allows the stirring speed to be maintained at a more feasible level. This is also helpful when increasing production capacity by expanding the reactor size, as high-speed stirring becomes difficult as the size and weight of mechanical parts increase as the reactor size grows. Since Geldart Group A particles have low cohesiveness, they do not require larger stirrs or excessively high speeds even when using a larger charge amount, allowing production capacity to be increased without causing the aforementioned negative consequences.

[0045] The present invention can also be used in a process in which relatively large porous particles are used in steps (a) to (c) and said particles are ground in a subsequent step. In particular, in such a process, preferably after step (c), D in step (d). 50 Preferably, the method further includes a step of crushing a plurality of particles by mechanical action to reduce the particle diameter. In this embodiment, D of the porous particles provided in step (a) 50 The particle diameter may be at least 20 μm, preferably at least 30 μm, more preferably at least 40 μm, more preferably at least 50 μm, and more preferably at least 100 μm. Preferably, D of the porous particles 50The particle diameter is 20 μm to 200 μm, preferably 30 μm to 200 μm, more preferably 40 μm to 200 μm, and more preferably 50 μm to 150 μm. The porous particles provided in step (a) may also have a D1 particle diameter of at least 1.5 μm, preferably at least 2 μm, more preferably at least 2.5 μm, and more preferably at least 3 μm. The porous particles provided in step (a) may also have D 10 The particle diameter may be at least 3 μm, preferably at least 5 μm, more preferably at least 10 μm, more preferably at least 15 μm, more preferably at least 20 μm, and more preferably at least 30 μm. The porous particles provided in step (a) are also D 90 The particle diameter may be 500 μm or less, preferably 400 μm or less, more preferably 300 μm or less, more preferably 250 μm or less, and more preferably 200 μm or less. The porous particles provided in step (a) are also D 98 The particle diameter may be 750 μm or less, preferably 500 μm or less, more preferably 400 μm or less, more preferably 300 μm or less, and more preferably 250 μm or less. These larger particles can be more easily aerated by processing according to the parameters discussed earlier, and as a result, a more uniform reaction process can be achieved throughout the particles. However, D 50 Composite particles with a particle diameter of less than 20 μm are considered advantageous for the desired end use of such composite materials in metal-ion batteries. Therefore, preferably, step (d) involves grinding a plurality of particles to D 50It includes reducing the particle diameter to less than 20 μm, preferably less than 15 μm, preferably less than 10 μm, most preferably less than 5 μm, or less than 3 μm. In particular, composite particles with a particle diameter of less than 5 μm are more difficult to manufacture by depositing them on particles of that size without undergoing a grinding process.

[0046] In an embodiment in which the particles undergo a grinding process, the plurality of porous particles provided in step (a) preferably have a span of 5 or less, preferably 4 or less, more preferably 3 or less, more preferably 2 or less, more preferably 1.5 or less, and more preferably 1 or less. The porous particles provided in step (a) may exhibit positive skewness in a volume-based particle diameter distribution. Preferably, D 50 The diameter is smaller than the volume-based average particle diameter. Preferably, the skewness of the porous particle diameter distribution (Malvern Mastersizer TM 3000 (measured by an analyzer) is 4 or less, 3 or less, 2 or less, or 1.5 or less. Preferably, the skewness is at least 0.2, at least 0.3, or at least 0.4. In an embodiment in which the particles undergo a grinding process, after the deposition of elemental silicon within the pores of the porous particles is completed, the particles may undergo passivation and cooling as previously discussed, and in some cases, passivation and cooling may be performed simultaneously. Cooling the particles has the advantage of making it easier to transfer the intermediate particles to the grinding device.

[0047] After selectively passivating and cooling the particles, they can be removed from the reactor and transferred to a grinding device. Grinding can be performed using various types of grinding devices, such as mills, wet mills, ball mills, jet mills, high-shear stirring, and ultrasonic grinding. Preferably, since the electroactive material deposited by the CVI process may be highly reactive, it is desirable to perform grinding in a dry mill immediately after deposition, taking into account the reactivity of the particles, especially if a passivation step has not been performed. For example, silicon deposited from silane contains a significant amount of Si-H bonds. These bonds are reactive with organic molecules and water. Therefore, if oxygen or organic solvents are present, an exothermic reaction occurs, which may cause the Si / C composite material to be partially destroyed and / or degrade to a quality below that required for commercial metal-ion battery materials.

[0048] Among dry mills, jet mills are preferred due to their ability to grind to smaller sizes. Jet mills use compressed air or inert gas injected at high speeds to collide particles with each other. Jet mills can be used for starting materials up to about 1 mm in size, and it is known that a size of about 1 μm can be easily obtained with relatively low energy input.

[0049] Preferably, each of the plurality of porous particles comprises a porous framework containing micropores and / or mesopores, generally a carbon framework. Preferably, the total pore volume of micropores and mesopores measured by gas adsorption is 0.1 to 4.0 cm³. 3 It is within the range of / g, preferably 0.2 to 3.0 cm 3 / g range, preferably 0.4 to 2.2 cm 3 It is within the / g range. Preferably, PD measured by gas adsorption method 50The pore diameter is 20 nm or less, preferably 10 nm or less, more preferably 5 nm or less. Preferably, the volume ratio of micropores to mesopores is 90:10 to 30:70, preferably 90:10 to 40:60, or 90:10 to 50:50, or 90:10 to 55:45, or 90:10 to 60:40, or 85:15 to 65:35.

[0050] In this specification, all references to the volumes of micropores, mesopores, and macropores within porous particles, and all references to the pore volume distribution within porous particles, refer to the internal pore volume of the porous particles used as starting materials in the claimed process, that is, the internal pore volume prior to silicon deposition.

[0051] "PD" used in this specification 50 The term “pore diameter” refers to the volume-based 50th percentile pore diameter based on the total volume of micropores and mesopores (i.e., 50% of the total volume of micropores and mesopores exists below this pore diameter). Pore diameter is also described in the art as “pore width,” and for the purposes of this application, the two terms are understood to be the same.

[0052] The total volume of micropores and mesopores and the pore size distribution of micropores and mesopores were determined by applying quenched solid density functional theory (QSDFT) according to the standard method specified in ISO 15901-2:2022, where the relative pressure p / p0 is 10 -7Measurements are taken using the nitrogen gas adsorption method at 77K until [the value is reached]. Nitrogen gas adsorption is a technique that characterizes the porosity and pore diameter distribution of a material by causing gas to condense within the pores of a solid. As pressure increases, the gas first condenses into the pores with the smallest diameters, and the pressure is increased until a saturation point is reached where all pores are filled with liquid. Then, the nitrogen gas pressure is gradually lowered to allow the liquid to evaporate from the system. Pore volume and pore size distribution can be measured through the analysis of adsorption and desorption isotherms and the hysteresis between them. Suitable equipment for measuring pore volume and pore size distribution by nitrogen gas adsorption includes the ASAP 2020 Plus porosity analyzer supplied by Micromeritics Instrument Corporation and the Autosorb IQ porosity analyzer supplied by Quantachrome Instruments.

[0053] Porous particles preferably have a BET surface area of ​​at least 500 m² 2 g -1 , at least 750 m 2 g -1 , at least 1,000 m 2 g -1 , at least 1,250 m 2 g -1 , or at least 1,500 m 2 g -1 The term "BET surface area" as used herein shall be understood to mean the surface area per unit mass calculated by measuring the physical adsorption of gas molecules on a solid surface using the Brunauer-Emmett-Teller theory in accordance with ISO 9277:2022. In other words, the measurement of the BET surface area of ​​porous particles refers to the porous particles used as starting materials in the claimed process, i.e., the porous particles prior to silicon deposition. Preferably, the BET surface area of ​​the porous particles is 4,000 m²2 g -1 Below, 3,500 m 2 g -1 Below, 3,250 m 2 g -1 Below, 3,000 m 2 g -1 Below, 2,500 m 2 g -1 Less than, or 2,000 m 2 g -1 It is as follows. For example, the BET surface area of ​​a porous particle is 750 m² 2 g -1 to 4,000 m 2 g -1 Range, 1,000 m 2 g -1 to 3,500 m 2 g -1 Range, 1,250 m 2 g -1 to 3,250 m 2 g -1 Range, or 1,500 m 2 g -1 to 3,000 m 2 g -1 It may be within the range.

[0054] Another factor to balance is the volume of the reactor swept by the stirring member during the stirring process. On the one hand, it is desirable for the stirring member to sweep a significant portion of the reactor volume to act directly on a significant portion of the particle layer. On the other hand, if this ratio is excessively high, it may hinder the complete circulation of particles within the reactor. Therefore, it is desirable for the stirring member to move through 5% to 90% of the internal volume during stirring, preferably 10% to 80%, more preferably 20% to 70%, and most preferably 30% to 60%. The volume moved during the stirring process can be adjusted independently of the stirring surface area. For example, in a rotary stirring member including a ribbon flight stirring member, the surface area can be increased without changing the volume moved during stirring by placing additional ribbons at the same radius. Adding more ribbons can increase the momentum that can be effectively transferred to the particle clusters without changing the volume of the reactor swept through each time the stirring action is repeated. In this way, by increasing the stirring speed or increasing the number of stirring elements passing through the same volume, the amount of energy input into the aeration of the particle layer can be adjusted independently of the proportional swept volume.

[0055] The present invention is particularly applicable to a reactor comprising a stirring member located in an internal volume that rotates the stirring member around the central axis of the internal volume to stir a plurality of porous particles. While this method is preferred, the principle of the present invention is expected to be applicable to reactors equipped with other types of stirrers, such as reciprocating stirrers.

[0056] In an embodiment in which a stirring member located in an internal volume is rotated about a central axis, preferably, the internal volume has substantially continuous rotational symmetry about the central axis. While this shape is preferred, it is expected that the internal volume may have a more complex shape and, for example, may include an outer surface contoured along the periphery to induce a favorable movement pattern of the stirred particles.

[0057] In addition, it has been found to be particularly desirable for the rotary stirring member to form an open center around the central axis. This has been shown to allow for smooth circulation of particles within the reactor. For example, in a vertical reactor design where the stirring member lifts particles against gravity, good vertical mixing can be ensured by allowing the particles to fall back down into the reactor through the open center around the central axis. This creates a good balance by producing particularly excellent synergy with the particle charge parameters and stirring speed described earlier. Alternatively, in the case of a horizontal reactor, the open center can enable smooth circulation so that particles move toward the central axis and then away from the central axis during stirring. Preferably, the radius of the open center of the stirring member (measured from the central axis) is 10% to 90%, preferably 15% to 80%, more preferably 20% to 70%, even more preferably 25% to 60%, and most preferably 30% to 50% of the distance between the central axis and the outer wall (e.g., radius of the internal volume). Preferably, the open center extends along the central axis direction over nearly the entire length of the stirring member.

[0058] Preferably, each stirring surface is an area of ​​the stirring member that forms an angle of 10° to 70° with respect to the velocity vector during stirring, preferably 20° to 60°, more preferably 30° to 50°, and / or an angle of less than 45° with respect to the velocity vector during stirring. This corresponds to a surface tilted relatively backward from the velocity vector, which tends to reduce movement occurring in the particle layer along the direction of the velocity vector.

[0059] In addition, it has been found desirable to provide one or more stirring surfaces over 50% to 100% of the outer wall length, preferably over at least 60% to 90% of the outer wall length, and more preferably over 60% to 80% of the outer wall length. In particular, it is desirable to provide one or more stirring surfaces substantially continuously along this ratio of the outer wall length. In a vertical reactor, it is particularly desirable to provide one or more stirring surfaces extending substantially continuously from the bottom of the internal volume to 50% to 95% of the outer wall length, preferably 60% to 90%, and more preferably 60% to 80%. Providing an open headspace over the stirring member in the internal volume can help promote vertical circulation of the particle layer, as particles can fall back down from the top of the internal volume. In a horizontal reactor, it is more advantageous to ensure good distribution along the outer wall rather than providing one or more stirring surfaces substantially continuously along the outer wall. In a horizontal reactor, preferably one or more stirring surfaces are provided over 50% to 100% of the outer wall length and are substantially uniformly distributed along the length of the outer wall, more preferably one or more stirring surfaces are provided over 60% to 100% of the outer wall length, more preferably 70% to 100%, and most preferably 80% to 100%.

[0060] As previously mentioned, the process is preferably carried out in a substantially vertical reactor, where "vertical" refers to the direction in which gravity acts. A substantially vertical direction can be considered to be within 45° from the vertical direction, preferably within 40°, more preferably within 30°, more preferably within 20°, more preferably within 10°, and most preferably within 5°. In a vertical reactor using a rotary stirring member, the central axis of rotation of the stirring member is also generally substantially vertical.

[0061] In a vertical reactor, the outer wall generally extends substantially vertically (e.g., a cylindrical outer wall) and may be in the shape of a truncated cone with a substantially vertical central axis. The stirring surface of the vertical reactor can generally be positioned to push the porous particles up along the outer wall against gravity (i.e., lift the particles upward in the vertical reactor) and / or away from the outer wall (i.e., toward the center) as the stirring surface moves through the porous particles. The vertical reactor may have a floor at the base of the outer wall, which further contributes to defining the internal volume. The floor may be flat, generally curved such as hemispherical or conical, or a combination of flat and curved shapes. In the vertical reactor, the stirring surface preferably extends from the floor up to 5 cm, preferably 1 cm, more preferably 5 mm, and more preferably 2 mm. Alternatively or additionally, the stirring surface may be extended within a distance corresponding to up to 2% of the reactor height, preferably up to 1%, more preferably up to 0.5%, and most preferably up to 0.2%. This allows the stirring surface to push out particles near the bottom of the reactor and ensure smooth circulation.

[0062] In a substantially vertical reactor, each stirring surface may be an area of ​​the stirring member that forms an angle of inclination with respect to the gravity vector during stirring, and may be positioned to lift multiple particles opposite to the direction of the gravity vector as the stirring surface moves through multiple porous particles. This is in addition to the fact that during the stirring process, each stirring surface is an area of ​​the stirring member that forms an angle of inclination with respect to the velocity vector. Generally, the direction of the velocity vector is nearly perpendicular to the direction of the gravity vector. Preferably, each stirring surface is an area of ​​the stirring member that forms an additional angle of 20° to 80°, preferably 30° to 70°, more preferably 40° to 60° with respect to the gravity vector during stirring, and / or an angle exceeding 45° with respect to the gravity vector during stirring. The angle of the stirring surface may be selected to balance the tangential movement occurring during stirring with the lifting and aeration of the particle layer. There is also the advantage that the larger the angle with respect to the gravity vector, the less torque is required to rotate the stirring member.

[0063] In this technology, various types of stirring surfaces may be used. However, preferably, the stirring member comprises a helical stirring surface, preferably at least two separate helical stirring surfaces, and more preferably at least three helical stirring surfaces. Helical or ribbon-shaped stirring surfaces are particularly useful for rotary stirring for the smooth circulation of particles. Helical stirring surfaces can be used in both vertical and horizontal reactors. When multiple independent helical stirring surfaces are used, they generally rotate in the same direction around the same central axis, and generally two helical stirring surfaces are tightly connected to each other.

[0064] There are several distinct operating modes for the way gas is introduced into the reactor. The first operating mode is the full batch method. In the full batch method, multiple porous particles or porous particle charges are supplied into the reactor and sealed. Then, after the gas or gas charge is introduced into the reactor, the gas supply is stopped and the reactor is sealed, and the particle layer is stirred while maintaining conditions inside the reactor effective for inducing a reaction between the multiple porous particles and the gas. The effluent gas can be discharged without adding new reactive gas into the reactor.

[0065] The second mode of operation is a continuous or semi-continuous operation in which the introduction of reactive gas occurs continuously or semi-continuously. In this mode of operation, multiple porous particles may be handled in a batch manner as porous particle charges, provided as a single batch within the reactor, and sealed within the reactor. The continuous or semi-continuous operation involves introducing gas into the reactor periodically or continuously while stirring the porous particles or porous particle charges and maintaining the interior of the reactor under conditions effective for inducing a reaction between the multiple porous particles and the gas, and optionally, the effluent gas may be discharged. In principle, the continuous operation does not exclude the possibility of fluctuations in the flow rate of reactive gas entering the reactor or the flow rate of effluent gas exiting the reactor. For example, the continuous reactor may be operated in a pulsed manner. For example, the flow rate of reactive gas entering the pressure reactor may be reduced to facilitate the discharge of effluent gas from the pressure reactor. Alternatively, the reactive gas may be introduced into the pressure reactor at a constant pressure. The discharge of effluent gas may be performed continuously so that the supply of reactive gas and the discharge of effluent gas from the reactor both occur continuously and simultaneously while the reaction is in progress. Alternatively, the discharge of effluent gas from the pressure reactor may be performed semi-continuously. As used herein, "semi-continuous" means that the effluent gas is removed intermittently.

[0066] Although this technology aims to improve the uniformity of the particle layer during stirring, in many embodiments, significant variations in the density of the particle layer may still occur throughout the internal volume during stirring, for example, a phenomenon in which the density increases toward the outer wall may occur. Particularly in reactors using rotary stirring surfaces, the particle density is generally higher near the outer wall due to centrifugal force during stirring. Therefore, to further suppress non-uniformity that may occur in the final product due to variations in particle density during stirring, gas is preferably introduced into the internal volume of the reactor through a plurality of inlets leading to the internal volume, wherein the plurality of inlets are arranged such that the flow rate of gas entering the internal volume per unit area increases from the central axis toward the outer wall in a plane perpendicular to the central axis of the internal volume (e.g., the rotational axis of the stirring member). Generally, this can be achieved by controlling the size, number, and / or density of inlets located across the entire bottom of a vertical reactor and / or by varying the flow rate of gas passing through each inlet (i.e., the size, number, and density of inlets across the entire bottom can be constant per unit area).

[0067] Another factor in vertical reactors, where the stirring element acts to lift particles against gravity, is that particle density tends to increase towards the bottom of the reactor. In some embodiments, gas is introduced into the internal volume of the reactor through multiple inlets penetrating the outer wall, and these inlets are positioned so that the flow rate of gas entering the internal volume per unit area of ​​the outer wall decreases along the outer wall in a direction opposite to the direction of the gravity vector. In vertical reactors, particle density is generally highest at the bottom, and since gas introduced through the outer wall tends to rise through the particle layer, it can be difficult to ensure that the upper and lower parts of the particle layer within the reactor are evenly exposed to gas when gas is introduced through the outer wall. This configuration allows the gas flow rate to be appropriately controlled to suit the characteristics of the stirred particle layer. In other words, this change in the gas flow rate entering the internal volume can be achieved by controlling the size, number, and / or density of the inlets located along the outer wall, and / or controlling the flow rate of the gas passing through each inlet.

[0068] As an additional option, gas may be introduced into the internal volume of the reactor through a plurality of inlets located in the stirring member, preferably the plurality of inlets are arranged so that the flow rate of the gas entering the internal volume decreases along the stirring member, and most preferably, so that it decreases in a direction opposite to the direction of the gravity vector.

[0069] In some embodiments, the above techniques can be combined to more precisely control the flow rate of gas entering the internal volume.

[0070] Although the process can substantially be used at atmospheric pressure, e.g., about 100 kPa, it is also suitable for use at high pressure, so the pressure within the internal volume during step (c) is preferably at least 100 kPa, preferably at least 200 kPa, more preferably at least 300 kPa, more preferably at least 500 kPa, more preferably at least 650 kPa, more preferably at least 750 kPa, more preferably at least 1000 kPa, more preferably at least 1500 kPa, more preferably at least 2000 kPa, more preferably at least 2500 kPa, more preferably at least 3000 kPa. Since increasing the pressure can promote the consolidation of particles, stirring in the manner described above can improve the handling properties of the particles under these high-pressure conditions.

[0071] Since high pressure is more difficult to generate and maintain, the pressure within the internal volume during step (c) is preferably 6000kPa or less, more preferably 5000kPa or less, more preferably 4000kPa or less, more preferably 3000kPa or less, more preferably 2000kPa or less, more preferably 1600kPa or less, more preferably 1500kPa or less, more preferably 1200kPa or less, more preferably 1000kPa or less, more preferably 900kPa or less, more preferably 800kPa or less, more preferably 700kPa or less, more preferably 650kPa or less, more preferably 600kPa or less, more preferably 300kPa or less.

[0072] In particular, preferably, during step (c), the pressure within the internal volume is 200 kPa to 6000 kPa, preferably 300 kPa to 5000 kPa, more preferably 400 kPa to 4000 kPa, and more preferably 500 kPa to 3000 kPa.

[0073] Preferably, during step (c), the temperature within the internal volume is in the range of 350 to 500°C, for example, 350 to 450°C, 360 to 430°C, 370 to 420°C, or 370 to 400°C.

[0074] The process may be carried out in such a manner that multiple porous particles are introduced and removed in a batch manner, or in such a manner that a feedstock of porous particles is provided and the porous particles are continuously introduced into the reaction zone of the reactor. In the latter embodiment, for example, a stirring member may be used to move the particles through the reaction zone out as part of a continuous process. Additionally, the process may be carried out in such a manner that gas is introduced substantially continuously or semi-continuously into the internal volume during step (c), as well as in such a manner that gas is introduced in a phased or staggered manner.

[0075] As previously discussed, the full batch method may include a pressure within the internal volume during step (c) being at least 300 kPa, preferably at least 500 kPa, more preferably at least 650 kPa, more preferably at least 750 kPa, more preferably at least 1000 kPa, more preferably at least 1500 kPa, more preferably at least 2000 kPa, more preferably at least 2500 kPa, more preferably at least 3000 kPa. The full batch method may also include a pressure within the internal volume during step (c) being 6000 kPa or less, preferably 5000 kPa or less, more preferably 4000 kPa or less, more preferably 3000 kPa or less. In particular, the pressure may be 300 kPa to 6000 kPa, preferably 400 kPa to 5500 kPa, more preferably 500 kPa to 5000 kPa, more preferably 750 kPa to 4500 kPa, more preferably 1000 kPa to 4000 kPa, and more preferably 2000 kPa to 3000 kPa. Meanwhile, the continuous or semi-continuous method may include a pressure within the internal volume during step (c) of at least 100 kPa, preferably at least 200 kPa, more preferably at least 300 kPa, more preferably at least 500 kPa, more preferably at least 600 kPa, more preferably at least 650 kPa, more preferably at least 700 kPa, more preferably at least 750 kPa, and more preferably at least 800 kPa.The continuous or semi-continuous batch method also has a pressure within the internal volume during step (c) of 2000 kPa or less, preferably 1500 kPa or less, more preferably 1000 kPa or less, more preferably 800 kPa or less, more preferably 750 kPa or less, more preferably 700 kPa or less, more preferably 650 kPa or less, more preferably 600 kPa or less, more preferably 600 kPa or less, more preferably 500 kPa or less, more preferably 300 kPa or less, more preferably 200 kPa or less. In particular, the pressure may be 100 kPa to 2000 kPa, preferably 100 kPa to 1000 kPa, more preferably 100 kPa to 500 kPa, and more preferably 100 kPa to 200 kPa or less than 200 kPa. In continuous or semi-continuous methods, pressure is focused on utilizing high pressure to increase the contact time of the continuous gas flow. Since continuous or semi-continuous methods generally allow for the simultaneous supply and discharge of gas from the reactor, pressure does not need to be as high as in full-batch methods; conversely, in full-batch methods, higher pressure results in a greater quantity of the desired reactive gas component. Continuous or semi-continuous methods can reduce synthesis time compared to batch gas injection methods and offer advantages in terms of equipment cost and safety as they do not require the use of such high pressure.

[0076] Preferably, the process further includes a step of exhausting exhaust gas from an internal volume during step (c), and the exhaust is preferably performed substantially continuously or semi-continuously as previously mentioned.

[0077] Preferably, the gas is a silicon precursor gas, and the space time of the silicon precursor gas in contact with the porous particles in step (c) is maintained within the range of 1 to 60 minutes, 2 to 45 minutes, 3 to 30 minutes, 4 to 25 minutes, or 5 to 20 minutes.

[0078] Preferably, the silicon precursor is selected from silane (SiH4), disilane (Si2H6), trisilane (Si3H8), methylsilane, dimethylsilane, and chlorosilane.

[0079] In a second aspect of the present invention, a composition comprising or made of silicon-containing composite particles obtainable by a process according to the first aspect of the present invention is provided. Preferably, 25 to 70 weight percent of the composite particles is elemental silicon.

[0080] In a third aspect, the present invention provides an electrode comprising silicon-containing composite particles that can be obtained by a process according to the first aspect of the present invention.

[0081] In a fourth aspect, the present invention provides a rechargeable metal-ion battery comprising an electrode according to the third aspect of the present invention.

[0082] According to a fifth aspect of the present invention, a process for treating particles is provided, the process comprises the following steps: (a) providing a plurality of porous particles in a reactor, wherein the reactor has an outer wall defining an internal volume for accommodating the plurality of porous particles; (b) stirring the plurality of porous particles with a stirring member located in the internal volume, wherein the stirring member has one or more stirring surfaces, each stirring surface is a region of the stirring member that forms an angle of inclination with respect to a velocity vector during stirring, and wherein the plurality of porous particles are arranged such that as the stirring surface moves through the plurality of porous particles, the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall, wherein the outer wall is movable to induce stirring of the plurality of particles, and one or more stirring surfaces of the stirring member protrude from the inner surface of the movable outer wall; Or the stirring member forms a gap between the stirring member and the inner surface of the outer wall, said gap being less than 10% of the internal dimensions of the reactor measured along the gap direction; and during stirring, the mass of the plurality of porous particles contained in the internal volume varies according to the volume of the internal volume and is 500 kg m⁻² -3 It is less than or equal to, and varies depending on the surface area of ​​one or more of the above stirring surfaces, and 1000 kg m² -2 A step in which the stirring surface passes through 5% to 90% of the internal volume during each stirring cycle of the stirring action and completes 0.1 to 10 stirring cycles per second; and (c) while stirring the plurality of porous particles, contact the plurality of porous particles and the gas under conditions effective for inducing a reaction between the plurality of porous particles and the gas.

[0083] This aspect of the present invention configures the process by considering the ratio of the internal volume through which at least one stirring surface passes during a stirring cycle and how regularly the stirring surface completes the stirring cycle. As with the above embodiments, stirring is preferably performed by a stirring member rotating about a rotation axis, but the stirring cycle can also be provided by reciprocating stirring action.

[0084] All optional features described above with respect to the first aspect of the invention apply equally to this aspect of the invention. In particular, the preferred mass of particles, which varies depending on the internal volume and the surface area of ​​one or more stirring surfaces, also apply equally to this aspect.

[0085] In particular, it is desirable that the stirring surface passes through 10% to 90%, preferably 20% to 85%, more preferably 30% to 80%, and more preferably 40% to 70% of the internal volume during each stirring cycle of the stirring action.

[0086] In addition, it is desirable for the stirring surface to complete 0.5 to 8 stirring cycles per second, preferably 0.7 to 5 times per second, preferably 0.8 to 4.5 times per second, and most preferably 1 to 4 times per second.

[0087] A preferred combination would include: a case where the stirring surface passes through 10% to 90% of the internal volume during each stirring cycle and completes 0.5 to 8 stirring cycles per second; or a case where the stirring surface passes through 20% to 85% of the internal volume during each stirring cycle and completes 0.7 to 5 stirring cycles per second; or a case where the stirring surface passes through 30% to 80% of the internal volume during each stirring cycle and completes 0.7 to 5 stirring cycles per second; or a case where the stirring surface passes through 30% to 80% of the internal volume during each stirring cycle and completes 0.8 to 4.5 stirring cycles per second; or a case where the stirring surface passes through 40% to 70% of the internal volume during each stirring cycle and completes 1 to 4 stirring cycles per second. Such combinations define an operating range particularly preferred for the process.

[0088] In some embodiments, a plurality of porous particles belong to group A of Geldarts, for example, D 50 The particle diameter is within the range of 30 μm to 200 μm. Since Geldart Group A particles require relatively little energy to aerate, one or more stirring surfaces can complete 0.1 to 5 stirring cycles per second, preferably 0.5 to 4 stirring cycles per second, preferably 0.7 to 3 stirring cycles per second, and most preferably 0.8 to 2 stirring cycles per second. This is preferably combined with stirring surfaces that pass through 5% to 85%, 10% to 80%, 20% to 80%, or 30% to 70% of the internal volume during each stirring cycle.

[0089] In another embodiment, a plurality of porous particles belong to the Geldart group C, for example, D 50The particle diameter is less than 30 μm. Since Geldart Group C particles require relatively more energy to aerate, one or more stirring surfaces can complete stirring cycles of 0.7 to 10 times per second, preferably 0.8 to 8 times, preferably 1 to 6 times, and preferably 1.5 to 5 times. This is preferably combined with stirring surfaces that pass through 20% to 90%, preferably 30% to 85%, and preferably 40% to 80% of the internal volume during each stirring cycle. Brief explanation of the drawing

[0090] The present invention will be described below with reference to the attached drawings, wherein: FIG. 1 schematically illustrates a system suitable for performing a process according to one embodiment; FIG. 2 illustrates a stirring member included in the system of FIG. 1; FIG. 3 is a cross-sectional view of the reactor and stirring member in the system of FIG. 1 and 2; FIG. 4 is a cross-sectional view of the reactor and stirring member of the system of FIG. 1 and 2, illustrating one embodiment of the gas inlet arrangement; FIG. 5 is a cross-sectional view of the reactor and stirring member of the system of FIG. 1 and 2, illustrating another embodiment of the gas inlet arrangement; FIG. 6 is a cross-sectional view of the reactor and stirring member of the system of FIG. 1 and 2, illustrating another embodiment of the gas inlet arrangement; FIG. 7 illustrates a system suitable for performing a process according to one embodiment; Figure 8 shows a cross-sectional view of the reactor of Figure 7. Specific details for implementing the invention

[0091] FIG. 1 schematically illustrates a system (100) suitable for performing a process according to the present invention. The system (100) has a capacity of 30L (0.03m 3) includes a vertical reactor (1). As illustrated in FIG. 3, the reactor (1) includes a cylindrical outer wall (2) that extends vertically to define an internal volume in which a process can be performed. The reactor also includes a substantially flat bottom portion (6) at the bottom of the cylindrical outer wall (2), and the top is closed by a removable top portion (7). The cylindrical outer wall (2), bottom portion (6), and top portion (7) together form a cylindrical closed 30L (0.03m²) 3 ) The internal volume is limited, and the process according to the present invention can be performed within this internal volume.

[0092] This system further includes a stirring member (3) illustrated in FIG. 2. The stirring member (3) includes a central axis member (5), and the stirring member (3) is configured to rotate around the central axis member (5) when in use. There are a plurality of horizontal support rods extending radially from the central axis member (5), and these support rods are connected to and support two spiral stirring surfaces (4) extending outward from the horizontal support rods. Each spiral stirring surface (4) is a ribbon-shaped stirring surface that wraps around the central axis member (5) to form a double spiral shape. The shape and configuration of the stirring surfaces (4) are described in more detail below.

[0093] As shown in FIG. 3, the stirring member of FIG. 2 is inserted into the reactor (1) such that the central axis member (5) is positioned vertically in a state parallel and concentric with the cylindrical outer wall (2). Once inserted into the reactor, the upper part (7) is placed over the reactor (1) to close the upper opening of the reactor into which the stirring member is inserted. The upper part of the central axis member (5) is connected to a drive connection of the upper part (7), which is supported by a gas-tight bearing (not shown in the drawing), so that the motor (9) drives the drive system (10) to transmit rotational driving force through the upper part (7), thereby allowing the stirring member (3) to rotate inside the reactor. The periphery flange of the upper part (7) contacts the upper periphery flange of the outer wall (2), and the upper part (7) can be fixed to the outer wall by any suitable means, such as by bolting it to the outer wall (2) to form a hermetic seal.

[0094] As illustrated in FIG. 3, when inserted into the reactor (1), two spiral stirring surfaces (4) extend away from the central axis member (5) and toward the outer wall (2) of the reactor (1). The outer wall (2) may have a radius of about 12.1 cm from the central axis member (5). The spiral stirring surface (4) may have an outer radius of 11.9 cm to the outer edge adjacent to the outer wall (2) so that a narrow gap is formed between the spiral stirring surface (4) and the outer wall. The spiral stirring surface may have a width of about 5.5 cm along the radial direction. Each spiral stirring surface (4) makes about one full turn in height and extends substantially from the bottom portion (6) of the reactor to about 65% of the total internal height of the internal volume, so there is no stirring surface (4) in the upper 35% of the internal volume. In this embodiment, each spiral stirring surface (4) forms an angle of about 60° with respect to the vertical direction. In this embodiment, each helical stirring surface is substantially flat along the radial direction of the stirring member. Thus, for example, since the helical stirring surface (4) forms an angle of about 60° with respect to the vertical direction, rotation of the stirring member within the internal volume tends to push the particles upward along the outer wall (2), lifting and aerating the particle layer. Although each helical stirring surface in this embodiment is substantially flat along the radial direction of the stirring member, it is also possible to provide a helical stirring surface that forms a constant angle along the radial direction so that rotation of the stirring member within the internal volume tends to move the particles away from the outer wall (2) and toward the center of the internal volume.

[0095] You will understand that the dimensions regarding the volume of the reactor and the surface area of ​​the stirrer mentioned above are merely examples. For instance, the volume can be changed by increasing the height and diameter of the reactor shown in the drawing, and the surface area of ​​the stirrer can be changed by adjusting parameters related to the stirring surface, specifically the number of helical screws, the angle formed with respect to the vertical direction, the inner and outer radii of the helical screws, and the height of the screws.

[0096] As will be discussed in more detail below, the process performed using this reactor involves injecting silicon precursor gas into the internal volume during stirring. This is generally performed using a series of gas inlets penetrating the outer wall (2), bottom section (6), and / or stirring member (3), as described below. Generally, as the silicon precursor gas is injected, exhaust gas is also discharged from the reactor. This can be done, for example, through a gas outlet (not shown in the drawing) that may be located at the top section (7).

[0097] FIG. 4 schematically illustrates a process performed using the reactor described above, in particular showing a method of injecting silicon precursor gas into the reactor. As shown in FIG. 4, when the stirring member (3) rotates within the internal volume of the reactor (1), the particle layer (11) rotates and is lifted to form a vortex shape. As a result of this vortex generated during the stirring process, the particle density maintains the highest level at the bottom of the internal volume, particularly at the periphery of the internal volume. FIG. 4 shows a method of injecting gas into the internal volume through a gas inlet (12) positioned in the cylindrical outer wall (2). Although the gas inlets (12) can be uniformly placed along the cylindrical outer wall, this is not suitable for obtaining a uniform final product due to the shape of the stirred particle layer (11) and the tendency of the injected gas to rise upward through the reactor. Accordingly, in this embodiment, gas inlets (12) are arranged along the cylindrical outer wall (2) such that the flow rate of gas entering the internal volume decreases as it moves upward along the cylindrical outer wall (2). This change in gas flow rate can be achieved in various ways. More or larger inlets can be provided toward the bottom of the outer wall to increase the surface area of ​​the cylindrical outer wall (2) into which the silicon precursor gas is injected. Alternatively, the arrangement of the inlets (12) can be uniform along the outer wall, and the gas can be injected at a higher flow rate through inlets closer to the bottom of the reactor. These techniques may also be combined. The precise gradient of the flow rate along the outer wall of the reactor can be changed as desired to suit the specific process to be performed within the reactor.

[0098] FIG. 5 schematically illustrates another process performed using the reactor described above, and in particular, shows a different method of injecting silicon precursor gas into the reactor. As described above in relation to FIG. 4, when the stirring member (3) rotates within the internal volume of the reactor (1), the particle layer (11) rotates and is lifted to form a vortex shape. In this embodiment, instead of the gas being injected through the cylindrical outer wall (2), the silicon precursor gas is injected through an inlet (12) located at the bottom portion (6) of the reactor (1). Due to the vortex shape of the stirred particle layer (11), the particle density per unit area of ​​the bottom portion (6) is generally higher toward the outer wall (2) of the reactor (1). Therefore, the inlet (12) can be positioned so that the flow rate per unit area of ​​the bottom portion is uniform, but in this embodiment, the inlet is positioned so that the flow rate per unit area of ​​the bottom portion (6) becomes higher toward the outer wall (2). In other words, this can be achieved by providing more or larger inlets toward the outer wall and / or injecting gas at a higher flow rate through inlets closer to the outer wall (2).

[0099] FIG. 6 schematically illustrates another process performed using the reactor described above, and in particular, another method of injecting silicon precursor gas into the reactor. In this embodiment, silicon precursor gas is injected into the internal volume of the reactor (1) using an inlet (12) placed in the stirring member (3). This can be achieved by providing a gas conduit that passes through the central axis member (5) of the stirring member (3), passes through a horizontal support rod, passes through the inside of a spiral ribbon, and extends to an inlet located along any side or edge of the ribbon. In other words, considering the particle density that varies throughout the stirring particle layer (11), the inlet (12) is positioned so that the flow rate into the internal volume increases as it moves from the stirring member toward the bottom of the reactor. Likewise, this can be achieved by providing more or larger inlets in the stirring member toward the bottom of the reactor. Alternatively, gas may be injected at a higher flow rate through an inlet closer to the bottom of the reactor. For this purpose, multiple parallel conduits may be required inside the stirring member, thereby allowing the flow rates to be controlled independently.

[0100] You will understand that by combining the inlet arrangements of Figures 4 to 6, the gas injection profile of the silicon precursor gas can be controlled more precisely.

[0101] Although the reactors described above were all vertical reactors, this principle is also applicable to horizontal reactors, and examples thereof are explained below.

[0102] FIG. 7 shows an example of a system (100) including a horizontal reactor (1). In this embodiment, the outer wall (2) of the reactor (1) is again a cylindrical outer wall (2), but this time the cylinder is positioned substantially horizontally. The reactor is supported by a central axis (50) that extends concentrically along the center of the cylindrical outer wall (2). The cylindrical outer wall (2) is closed at both ends with opposing end faces (60, 70), and the central axis (50) extends further from these end faces and is rotatably supported by a support structure of the system. A motor (9) and a drive system (10) are connected to one end of the central axis (50) and provided to drive the rotation of the axis, thereby causing the entire cylindrical outer wall (2) to rotate as well. An opening is provided at the opposite end of the central axis (50) to supply silicon precursor gas along the central axis, and the silicon precursor gas can be injected into the reactor (1) through an inlet (12) positioned on the central axis (50) inside the reactor (1).

[0103] FIG. 8 shows a cross-section of a cylindrical outer wall (2) perpendicular to the central axis (50). As shown in this figure, a plurality of stirring surfaces (4) protrude outward from the inner surface of the outer wall (2) toward the internal volume of the reactor. During stirring, each stirring surface is tilted at an angle θ with respect to the direction of the velocity vector. In this horizontal embodiment, this tilt causes the stirring surfaces to lift particles toward the central axis during stirring. Additionally, these stirring surfaces may form a certain angle with respect to the central axis direction during stirring, thereby further pushing particles along the outer wall during stirring. For example, different stirring surfaces may be angled in opposite directions with respect to the central axis direction, so that the stirring surfaces work together to lift the layer of particles during stirring while simultaneously promoting longitudinal mixing along the central axis direction.

[0104] Below, several exemplary processes are described in more detail.

[0105] Example Process 1

[0106] The first exemplary process uses the reactor described above in relation to FIGS. 1 to 3. The volume is 30 L (0.03 m³). 3 This reactor is loaded with 4.5 kg of porous particles containing porous carbon frameworks, each containing micropores and mesopores, which is an internal volume of 1 m³ 3 The charging amount is 150 kg per unit, and the surface area of ​​the mixing surface (4) is 1 m² 2 The charging amount is approximately 56 kg per unit. Because the gap between the stirring surface (4) and the outer wall (2) is very narrow, the porous particles are D 50 The particle diameter is provided to be less than 30 μm. In particular, the particle is D1 with a particle diameter of 0.9 μm, D 10 Particle diameter 3.2μm, D 50 Particle diameter 16.7μm, D 90 Particle diameter 41.1 μm and D 98 It can be provided with a particle diameter of 56.9 μm. This particle has a BET surface area of ​​1626 m² 2 g -1 , PD 50 This is 1.0 nm, the micropore-to-mesopore volume ratio is 69.6:30.4, and the pore volume of micropores and mesopores is 0.7 cm³ 3 g -1 ...was. This particle belonged to Geldart group C, the house width was 1.73, and the skewness in the volume-based particle diameter distribution was 0.87. The stirring element rotated at an angular velocity of 144 rpm, and as a result, the stirring speed per kg of particle was approximately 0.007 m 3 s -1 kg -1 This becomes. The stirring speed is calculated using the following equation:

[0107]

[0108] In the above formula is the outer radius of each ribbon, is the inner radius of each ribbon, is the height of each ribbon, is the stirring speed expressed in revolutions per minute, is the charged mass of porous particles.

[0109] In this embodiment, the stirring surface passes through approximately 45% of the internal volume of the reactor during stirring. This value is calculated using the following equation:

[0110]

[0111] In the above formula is the ratio of the internal volume of the stirred reactor, and is the total internal volume of the reactor.

[0112] The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom at a flow rate of 2 g of silicon per minute of silane gas per 1 kg of porous particles, and the exhaust gas is continuously discharged.

[0113] Example Process 2

[0114] In the second example process, the internal volume is 513L (0.513m 3 A larger vertical reactor is used, with a radius of 31.3 cm between the central axis and the outer wall. This reactor has a stirring element containing two spiral ribbons. Each ribbon forms an angle of 55° with respect to the vertical direction. Each ribbon has a radius of 31.0 cm to the outer edge and a radius of 9 cm to the inner edge. Each ribbon makes a full turn in height and extends from the bottom of the reactor to about 76% of the total internal height of the reactor.

[0115] The reactor includes a porous carbon framework and D 50 65 kg of porous particles with a particle diameter of 30 μm are charged. This charge amount covers an internal reactor volume of 1 m³ 3 It corresponds to approximately 127 kg per unit, with a mixing surface area of ​​1 m² 2It corresponds to approximately 85 kg per unit. The stirring element rotates at a speed of 90 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.008 m 3 s -1 kg -1 This is done. During stirring, the stirring surface passes through about 70% of the internal volume of the reactor. The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is injected into the internal volume under pressure through the outer wall, raising the pressure in the internal volume to 1000 kPa. While maintaining this pressure, exhaust gas is continuously discharged.

[0116] Example Process 3

[0117] The third example process shows a stirring element with a relatively small surface area compared to the particle charge amount. In this example, the internal volume is 30L (0.03m² 3 A vertical reactor is used, with a radius of 12.1 cm between the central axis and the outer wall. This reactor has a stirring member including one spiral ribbon. The spiral ribbon forms an angle of 25° with respect to the vertical direction. The radius to the outer edge of the ribbon is 11.9 cm, and the radius to the inner edge is 7 cm. The ribbon turns about 0.2 turns in height and extends from the bottom of the reactor to about 50% of the total internal height of the reactor.

[0118] The reactor includes a porous carbon framework and D 50 6 kg of porous particles with a particle diameter of 250 μm are charged. This charge amount corresponds to an internal reactor volume of 1 m³ 3 It corresponds to approximately 200 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 849 kg per unit. The stirring element rotates at a speed of 160 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.004 m 3 s -1 kg -1This is done. The reactor is heated to a temperature of about 370°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom at a flow rate of 2 g of silicon per minute of silane gas per 1 kg of porous particles, and the exhaust gas is continuously discharged.

[0119] Example Process 4

[0120] The fourth example process shows a stirring element with a relatively large surface area compared to the particle charge amount. In this example, the internal volume is 30L (0.03m² 3 A vertical reactor was used, with a radius of 12.1 cm between the central axis and the outer wall. This reactor had a stirring element containing four spiral ribbons. Each spiral ribbon forms an angle of 65° with respect to the vertical direction. Each ribbon had a radius of 11.9 cm to the outer edge and a radius of 4 cm to the inner edge. Each ribbon makes about 1.5 turns in height and extends from the bottom of the reactor to about 80% of the total internal height of the reactor.

[0121] The reactor includes a porous carbon framework and D 50 2 kg of porous particles with a particle diameter of 20 μm are charged. This charge amount corresponds to an internal reactor volume of 1 m³ 3 It corresponds to approximately 67 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 5 kg per unit. The stirring element rotates at a speed of 120 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.021 m 3 s -1 kg -1The reactor is heated to a temperature in the range of 330°C to 390°C suitable for gas injection. This example operates in a full batch mode. During stirring, silane (SiH4) gas is injected into the internal volume until a pressure of 1000 kPa is reached, at which point the gas supply is temporarily stopped. Then, the reactor is heated to a temperature in the range of 370°C to 420°C suitable for the reaction. After a predetermined time, the exhaust gas is removed from the reactor to bring the reactor to atmospheric pressure, and then silane gas is reinjected to raise the pressure to 1000 kPa, at which point the temperature for each step of the gas injection and reaction is controlled within the above range. This process is repeated until completion.

[0122] Example Process 5

[0123] In the 5th example process, the internal volume is 5000L (5m 3 It shows a very large vertical reactor with an internal radius of 67.5 cm. This reactor has a stirring element containing two spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 65.5 cm to the outer edge and a radius of 25.5 cm to the inner edge. Each ribbon makes about two-thirds of a turn in height and extends from the bottom of the reactor to about 60% of the total internal height of the reactor.

[0124] The reactor includes a porous carbon framework and D 50 1,000 kg of porous particles with a particle diameter exceeding 100 μm are charged. In particular, the particles are D1 particles with a diameter of 5.6 μm, D 10 Particle diameter 40.5μm, D 50 Particle diameter 104.0 μm, D 90 Particle diameter 185.0 μm and D 98 It can be provided with a particle diameter of 237.0 μm. This particle has a BET surface area of ​​1540 m² 2 g -1 , PD50 This is 5.0 nm, the micropore-to-mesopore volume ratio is 5.7:94.3, and the pore volume of micropores and mesopores is 1.76 cm³ 3 g -1 .... This particle belonged to Geldart Group A, the haus width was 1.02, and the skewness in the volume-based particle diameter distribution was 0.44. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 200 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 507 kg per unit. The stirring element rotates at a speed of 60 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.003 m 3 s -1 kg -1 This is done. The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall, bottom, and stirring member at a flow rate of 2 g of silicon in the silane gas per minute per 1 kg of porous particles, and the exhaust gas is continuously discharged.

[0125] Example Process 6

[0126] An example of a particularly desirable process is one with an internal volume of 30L (0.03m²) 3 A vertical reactor is used, with a radius of 12.1 cm between the central axis and the outer wall. This reactor has a stirring element including two spiral ribbons. Each spiral ribbon forms an angle of 45° with respect to the vertical direction. Each ribbon has a radius of 11.9 cm to the outer edge and a radius of 7.0 cm to the inner edge. Each ribbon makes about 0.6 turns in height and extends from the bottom of the reactor to about 70% of the total internal height of the reactor.

[0127] The reactor includes a porous carbon framework and D 50 5 kg of porous particles with a particle diameter of less than 30 μm are loaded. In particular, the particles are D1 particles with a diameter of 0.9 μm, D 10 Particle diameter 3.2μm, D50 Particle diameter 16.7μm, D 90 Particle diameter 41.1 μm and D 98 It can be provided with a particle diameter of 56.9 μm. This particle has a BET surface area of ​​1626 m² 2 g -1 , PD 50 This is 1.0 nm, the micropore-to-mesopore volume ratio is 69.6:30.4, and the pore volume of micropores and mesopores is 0.7 cm³ 3 g -1 ...was. This particle belonged to Geldart Group C, the haus width was 1.73, and the skewness in the volume-based particle diameter distribution was 0.87. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 167 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 100 kg per unit. The stirring element rotates at a speed of 150 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.007 m 3 s -1 kg -1 The reactor is heated to a temperature of approximately 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom section. The gas is injected through the bottom section such that the flow rate per unit area of ​​the bottom section increases from the central axis toward the outer wall, and through the outer wall such that the flow rate per unit area of ​​the outer wall decreases vertically along the outer wall. The exhaust gas during the process is continuously discharged.

[0128] Example Process 7

[0129] Another example of a particularly desirable process is one with an internal volume of 5000L (5m 3A vertical reactor is used, with a radius of 67.0 cm between the central axis and the outer wall. This reactor has a stirring element including three spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 66.5 cm to the outer edge and a radius of 25.5 cm to the inner edge. Each ribbon makes about 0.8 turns in height and extends from the bottom of the reactor to about 80% of the total internal height of the reactor.

[0130] The reactor includes a porous carbon framework and D 50 650 kg of porous particles with a particle diameter of less than 30 μm are charged. In particular, the particles are D1 particles with a diameter of 0.9 μm, D 10 Particle diameter 3.2μm, D 50 Particle diameter 16.7μm, D 90 Particle diameter 41.1 μm and D 98 It can be provided with a particle diameter of 56.9 μm. This particle has a BET surface area of ​​1626 m² 2 g -1 , PD 50 This is 1.0 nm, the micropore-to-mesopore volume ratio is 69.6:30.4, and the pore volume of micropores and mesopores is 0.7 cm³ 3 g -1 ...was. This particle belonged to Geldart Group C, the haus width was 1.73, and the skewness in the volume-based particle diameter distribution was 0.87. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 130 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 163 kg per unit. The stirring element rotates at a speed of 60 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.005 m 3 s -1 kg -1The reactor is heated to a temperature of approximately 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom section. The gas is injected through the bottom section such that the flow rate per unit area of ​​the bottom section increases from the central axis toward the outer wall, and through the outer wall such that the flow rate per unit area of ​​the outer wall decreases vertically along the outer wall. The exhaust gas during the process is continuously discharged.

[0131] Example Process 8

[0132] In the 8th example process, the internal volume is 0.6L (0.0006m 3 A small laboratory-sized reactor is used, with a radius of 4.10 cm between the central axis and the outer wall. This reactor has a stirring element containing three spiral ribbons. Each ribbon forms a 45° angle with respect to the vertical direction. Each ribbon has a radius of 3.95 cm to the outer edge and a radius of 2.95 cm to the inner edge. Each ribbon turns about halfway in height and extends from the bottom of the reactor to about 74% of the total internal height of the reactor.

[0133] The reactor includes a porous carbon framework and D 50 50g of porous particles with a particle diameter of 30μm are charged. This charging amount is for an internal reactor volume of 1m³ 3 It corresponds to approximately 83 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 15 kg per unit. The stirring element rotates at a speed of 250 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.02 m 3 s -1 kg -1This is done. During stirring, the stirring surface passes through about 40% of the internal volume of the reactor. The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is injected into the internal volume under pressure through the outer wall, raising the pressure in the internal volume to 1000 kPa. While maintaining this pressure, exhaust gas is continuously discharged.

[0134] Example Process 9

[0135] In the 9th example process, the internal volume is 5000L (5m 3 A vertical reactor with an inner radius of 67.5 cm is used. This reactor has a stirring element including two spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 65.5 cm to the outer edge and a radius of 25.5 cm to the inner edge. Each ribbon makes about one full turn in height and extends from the bottom of the reactor to about 96% of the total inner height of the reactor.

[0136] 1,000 kg of relatively large porous particles are charged into a reactor. In particular, the particles are D1 particles with a diameter of 5.6 μm, D 10 Particle diameter 40.5μm, D 50 Particle diameter 104.0 μm, D 90 Particle diameter 185.0 μm and D 98 It can be provided with a particle diameter of 237.0 μm. This particle has a BET surface area of ​​1540 m² 2 g -1 , PD 50 This is 5.0 nm, the micropore-to-mesopore volume ratio is 5.7:94.3, and the pore volume of micropores and mesopores is 1.76 cm³ 3 g -1 .... This particle belonged to Geldart Group A, the haus width was 1.02, and the skewness in the volume-based particle diameter distribution was 0.44. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 200 kg per unit, with a mixing surface area of ​​1 m²2 It corresponds to approximately 277 kg per unit. The stirring element rotates at a speed of 60 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.004 m 3 s -1 kg -1 This is done. The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall, bottom, and stirring member at a flow rate of 2 g of silicon in the silane gas per minute per 1 kg of porous particles, and the exhaust gas is continuously discharged.

[0137] When the reaction time was finished, the atmosphere inside the reactor was switched to pure nitrogen while maintaining fluidization, and this purging process continued for 30 minutes. Subsequently, the temperature of the furnace was gradually lowered to ambient temperature over several hours. After reaching ambient temperature, the atmosphere inside the furnace was gradually switched to air over several hours.

[0138] Next, the composite particles were placed into the feed tray of an MC DecJet® 30 mill and ground under an inert atmosphere. The ring pressure was set to 650 kPa and the venturi pressure to 700 kPa. After finely grinding the particles, they were placed in a suitable container. The D of the composite particles produced through this process 50 The particle diameter decreased to about 3 μm.

[0139] Example Process 10

[0140] The 10th example process is another example process that uses a large reactor, similar to the 2nd example process, but operates at a gentler pressure than that described in the 2nd example process. The reactor and stirring elements are identical to those described in the 2nd example process.

[0141] The particles used in this example process are D1 particles with a diameter of 0.8 μm, D 10 Particle diameter 1.8μm, D 50 Particle diameter is 4.8μm, D 90Particle diameter 8.5μm, D 98 The particle diameter is 10.7 μm. This particle has a BET surface area of ​​2584 m² 2 g -1 , PD 50 This is 1.9 nm, the micropore-to-mesopore volume ratio is 51.8:48.2, and the pore volume of micropores and mesopores is 1.25 cm³ 3 g -1 This particle belonged to the Geldart group C, had a house width of 1.89, and a skewness in the volume-based particle diameter distribution of 0.41.

[0142] As with the second example process, 65 kg of porous particles are charged into the reactor. This charge amount corresponds to an internal reactor volume of 1 m³ 3 It corresponds to approximately 127 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 85 kg per unit. The stirring element rotates at a speed of 90 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.008 m 3 s -1 kg -1 This is done. During stirring, the stirring surface passes through about 68% of the internal volume of the reactor. The reactor is heated to a temperature of about 380°C. During stirring, silane (SiH4) gas is injected into the internal volume under pressure through the outer wall, raising the pressure in the internal volume to 600 kPa. While maintaining this pressure, exhaust gas is continuously discharged.

[0143] Example Process 11

[0144] In the 11th example process, the internal volume is 30L (0.03m 3A vertical reactor is used, with a radius of 12.1 cm between the central axis and the outer wall. This reactor has a stirring member including one spiral ribbon. The spiral ribbon forms an angle of 25° with respect to the vertical direction. The radius to the outer edge of the ribbon is 11.9 cm, and the radius to the inner edge is 7 cm. The ribbon turns 0.2 turns in height and extends from the bottom of the reactor to about 50% below the total internal height of the reactor.

[0145] The particles used in this example process are D1 particles with a diameter of 5.6 μm, D 10 Particle diameter is 40.5 μm, D 50 Particle diameter is 104.0 μm, D 90 Particle diameter is 185.0 μm, D 98 The particle diameter is 237.0 μm. This particle has a BET surface area of ​​1540 m² 2 g -1 , PD 50 This is 5.0 nm, the micropore-to-mesopore volume ratio is 5.7:94.3, and the pore volume of micropores and mesopores is 1.76 cm³ 3 g -1 This particle belonged to Geldart group A, had a house width of 1.02, and a skewness in the volume-based particle diameter distribution of 0.44.

[0146] 6 kg of porous particles are charged into the reactor, and this charge amount corresponds to an internal volume of 1 m³ of the reactor. 3 It corresponds to approximately 200 kg per unit, with a mixing surface area of ​​1 m² 2 This amounts to approximately 852 kg per unit. The stirring element rotates at a speed of 90 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.002 m 3 s -1 kg -1 This becomes. The stirring surface passes through approximately 33% of the internal volume of the reactor during stirring. The remaining details of the reactor, stirring element, particle charge amount, and stirring speed were not changed.

[0147] Example Process 12

[0148] The 12th example process is another example that uses a stirring element with a relatively large surface area relative to the particle charge, similar to the 4th example process, but differs in that the particles used are different and the process was carried out at a higher pressure.

[0149] In this example, the internal volume is 30L (0.03m 3 A vertical reactor was used, with a radius of 12.1 cm between the central axis and the outer wall. This reactor had a stirring element containing four spiral ribbons. Each spiral ribbon forms an angle of 65° with respect to the vertical direction. Each ribbon had a radius of 11.9 cm to the outer edge and a radius of 4 cm to the inner edge. Each ribbon makes about 1.5 turns in height and extends from the bottom of the reactor to about 80% of the total internal height of the reactor.

[0150] In the reactor, D1 particles with a diameter of 1.0 μm, D 10 Particle diameter 3.0μm, D 50 Particle diameter 8.2μm, D 90 Particle diameter is 14.4 μm, D 98 Particles containing a porous carbon skeleton with a particle diameter of 18.4 μm are loaded. These particles have a BET surface area of ​​2222 m² 2 g -1 , PD 50 This is 0.9 nm, the micropore-to-mesopore volume ratio is 70.3:29.7, and the pore volume of micropores and mesopores is 0.97 cm³ 3 g -1 This particle belonged to Geldart group C, had a house width of 1.74, and a skewness in the volume-based particle diameter distribution of 0.43.

[0151] 2 kg of these porous particles were loaded into the reactor. This loading amount corresponds to an internal reactor volume of 1 m³ 3 It corresponds to approximately 67 kg per unit, with a mixing surface area of ​​1 m² 2It corresponds to approximately 5 kg per unit. The reactor is heated to a temperature in the range of 330°C to 390°C suitable for gas injection. Stirring is performed at a speed of 60 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.011 m 3 s -1 kg -1 This is done. During stirring, silane (SiH4) gas is injected into the internal volume until a high pressure of 1900 kPa is reached, at which point the gas supply is temporarily stopped. Then, the reactor is heated to a temperature in the range of 370°C to 420°C suitable for the reaction. After a predetermined time, the exhaust gas is removed from the reactor to bring the reactor to atmospheric pressure, and then silane gas is injected again to raise the pressure to 1900 kPa, at which point the temperature for each step of the gas injection and reaction is controlled within the above range. This process is repeated until completion.

[0152] Example Process 13

[0153] The 13th example process is generally similar to the 8th example process, but has a different particle composition and uses a pressure much closer to ambient pressure.

[0154] In particular, the reactor stirring element, particle charging amount, and stirring speed are the same as in the 8th example process. In this example process, the D1 particle diameter of the provided particles is 0.8 μm, D 10 Particle diameter 1.8μm, D 50 Particle diameter is 4.8μm, D 90 Particle diameter 8.5μm, D 98 It differs in that the particle diameter is 10.7 μm. This particle has a BET surface area of ​​2584 m² 2 g -1 , PD 50 This is 1.9 nm, the micropore-to-mesopore volume ratio is 51.8:48.2, and the pore volume of micropores and mesopores is 1.25 cm³ 3 g -1This particle belonged to the Geldart group C, had a house width of 1.89, and a skewness in the volume-based particle diameter distribution of 0.41.

[0155] After loading 50g of porous particles, the stirring member is rotated at a speed of 250 rpm, approximately 0.02m per 1kg of particles 3 s -1 kg -1 A stirring speed is obtained, and the reactor is heated to a temperature of approximately 380°C. During stirring, the stirring surface passes through approximately 40% of the internal volume of the reactor. During stirring, silane (SiH4) gas is injected into the internal volume under pressure through the outer wall, raising the pressure in the internal volume to a relatively low 190 kPa. While maintaining this pressure, the exhaust gas is continuously discharged.

[0156] Example 14

[0157] Another example of a particularly desirable process uses the same vertical reactor as the seventh example process. In particular, this reactor has an internal volume of 5000L (5m²) 3 The radius between the central axis and the outer wall is 67.0 cm. The stirring member has three spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 66.5 cm to the outer edge and a radius of 25.5 cm to the inner edge. Each ribbon makes about 0.8 turns in height and extends from the bottom of the reactor to about 80% of the total internal height of the reactor.

[0158] The reactor includes a porous carbon framework and D 50 650 kg of porous particles with a particle diameter of less than 30 μm are charged. In particular, the particles are D1 particles with a diameter of 0.9 μm, D 10 Particle diameter 3.2μm, D 50 Particle diameter 16.7μm, D 90 Particle diameter 41.1 μm and D 98It can be provided with a particle diameter of 56.9 μm. This particle has a BET surface area of ​​1626 m² 2 g -1 , PD 50 This is 1.0 nm, the micropore-to-mesopore volume ratio is 69.6:30.4, and the pore volume of micropores and mesopores is 0.7 cm³ 3 g -1 ...was. This particle belonged to Geldart Group C, the haus width was 1.73, and the skewness in the volume-based particle diameter distribution was 0.87. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 130 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to about 163 kg per person.

[0159] Due to the high cohesiveness of the particles, the stirring element in this example rotates at a faster speed of 120 rpm, and as a result, the stirring speed per kg of particles is approximately 0.010 m 3 s -1 kg -1 This becomes the case. The stirring surface passes through approximately 66% of the internal volume of the reactor during stirring. This improved the permeability of the particle layer compared to the lower stirring speed in the seventh example process. The reactor is heated to a temperature of approximately 380°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom section. The gas is injected through the bottom section such that the flow rate per unit area of ​​the bottom section increases from the central axis toward the outer wall, and through the outer wall such that the flow rate per unit area of ​​the outer wall decreases vertically along the outer wall. The exhaust gas during the process is continuously discharged.

[0160] Example 15

[0161] The 15th exemplary process shows a very large vertical reactor configured to process particles belonging to Geldart Group A, which is designed to produce a large amount of composite particles while maintaining good aeration of the particle layer. The reactor has an internal volume of 5000L (5m²) 3The inner radius is 67.0 cm. This reactor has a stirring member containing two spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 65.5 cm to the outer edge and a radius of 25.5 cm to the inner edge. Each ribbon makes about 0.7 turns in height and extends from the bottom of the reactor to about 60% of the total inner height of the reactor.

[0162] In the reactor, D1 particles with a diameter of 5.6 μm, D 10 Particle diameter is 40.5 μm, D 50 Particle diameter is 104.0 μm, D 90 Particle diameter is 185.0 μm, D 98 1,500 kg of porous particles containing a porous carbon skeleton with a particle diameter of 237.0 μm are charged. These particles have a BET surface area of ​​1,540 m² 2 g -1 , PD 50 This is 5.0 nm, the micropore-to-mesopore volume ratio is 5.7:94.3, and the pore volume of micropores and mesopores is 1.76 cm³ 3 g -1 .... This particle belonged to Geldart Group A, the haus width was 1.02, and the skewness in the volume-based particle diameter distribution was 0.44. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 300 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 760 kg per unit. The stirring element rotates at a speed of 50 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.001 m 3 s -1 kg -1This is the case. During stirring, the stirring surface passes through about 53% of the internal volume of the reactor. The reactor is heated to a temperature of about 395°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall, bottom, and stirring member at a flow rate of silicon in the silane gas of 2 g per minute per 1 kg of porous particles, and the exhaust gas is continuously discharged.

[0163] Compared to the fifth example process, this process used more porous particles and lowered the stirring speed. Since these particles belong to Geldart Group A and are relatively easy to aerate, the particle layer still maintained good air permeability even with a large charge and low stirring speed.

[0164] Example 16

[0165] The 16th exemplary process shows a very large vertical reactor configured to process Geldart Group C particles, which exhibit particularly high agglomeration. The reactor has an internal volume of 5000 L (5 m²) 3 The inner radius is 67.0 cm. This reactor has a stirring element including three spiral ribbons. Each spiral ribbon forms an angle of 50° with respect to the vertical direction. Each ribbon has a radius of 66.5 cm to the outer edge and a radius of 10.5 cm to the inner edge. Each ribbon makes about 0.8 turns in height and extends from the bottom of the reactor to about 80% of the total inner height of the reactor.

[0166] The reactor contains a porous carbon framework, and the D1 particle diameter is 0.8 μm, D 10 Particle diameter 1.8μm, D 50 Particle diameter is 4.8μm, D 90 Particle diameter 8.5μm, D 98 100 kg of porous particles with a particle diameter of 10.7 μm are loaded. These particles have a BET surface area of ​​2584 m² 2 g -1 , PD 50This is 1.9 nm, the micropore-to-mesopore volume ratio is 51.8:48.2, and the pore volume of micropores and mesopores is 1.25 cm³ 3 g -1 .... This particle belonged to Geldart Group C, the haus width was 1.89, and the skewness in the volume-based particle diameter distribution was 0.41. This charge amount was for a reactor internal volume of 1 m³ 3 It corresponds to approximately 20 kg per unit, with a mixing surface area of ​​1 m² 2 It corresponds to approximately 20 kg per unit. The stirring element rotates at a speed of 85 rpm, and as a result, the stirring speed per 1 kg of particles is approximately 0.054 m 3 s -1 kg -1 This becomes the case. During stirring, the stirring surface passes through approximately 76% of the internal volume of the reactor. The reactor is heated to a temperature of approximately 365°C. During stirring, silane (SiH4) gas is continuously injected into the internal volume through the outer wall and bottom. This gas is injected through the bottom at a flow rate of silicon in the silane gas of 2 g per minute per 1 kg of porous particles. The exhaust gas during the process is continuously discharged.

[0167] Compared to the seventh example process, this example process used particles with a smaller diameter. Although both particles belong to Geldart Group C, the smaller particles used in this example process have much stronger cohesive force and thus greater resistance to air. Therefore, in this example process, the particle loading amount was reduced, the width of the stirring element was widened, and the stirring speed was increased. As a result, the air permeability of the particle layer was improved despite the high cohesive force of the particles.

Claims

Claim 1 A process for processing particles, wherein the process comprises: (a) a step of providing a plurality of porous particles within a reactor, wherein the reactor has an outer wall defining an internal volume for accommodating the plurality of porous particles; (b) a step of stirring the plurality of porous particles with a stirring member located in the internal volume, wherein the stirring member has one or more stirring surfaces, each stirring surface is a region of the stirring member that forms an angle of inclination with respect to a velocity vector during stirring, and wherein the stirring surfaces are arranged such that as the stirring surfaces move through the plurality of porous particles, the plurality of porous particles move along the outer wall at a certain angle with respect to the velocity vector and / or move away from the outer wall, and wherein The outer wall is movable to induce stirring of the plurality of particles, and one or more stirring surfaces of the stirring member protrude from the inner surface of the movable outer wall; or The stirring member forms a clearance between the stirring member and the inner surface of the outer wall, said clearance being less than 10% of the internal dimensions of the reactor measured along the clearance direction; and during stirring, the mass of the plurality of porous particles contained in the internal volume varies according to the volume of the internal volume and is 500 kg m⁻² -3 It is less than or equal to, and varies depending on the surface area of ​​one or more of the above stirring surfaces, and 1000 kg m² -2 The above is as follows, and the volume passing through the one or more stirring surfaces per second during stirring depends on the mass of a plurality of porous particles contained in the internal volume, and the value is 0.001 to 0.1 m 3 s -1 kg -1 A process comprising: a step of; and (c) while stirring the plurality of porous particles, contacting the plurality of porous particles and the gas under conditions effective for inducing a reaction between the plurality of porous particles and the gas. Claim 2 The process according to claim 1, wherein the process is a process for manufacturing composite particles, and step (c) comprises the step of contacting the plurality of porous particles with a silicon precursor gas under conditions effective for depositing silicon within the pores of the porous particles while stirring the plurality of porous particles, thereby providing composite particles comprising a porous particle framework and elemental silicon present within the pores of the porous particle framework. Claim 3 In claim 1 or 2, the mass of the plurality of porous particles contained in the internal volume during stirring varies according to the volume of the internal volume, and is 400 kgm -3 Below, preferably 300 kgm -3 Below, more preferably 250 kgm -3 A process that is less than or equal to the following. Claim 4 In any one of claims 1 to 3, the mass of the plurality of porous particles contained in the internal volume during stirring varies according to the volume of the internal volume, and is 15 kgm -3 Above, preferably 50 kgm -3 Ideally, 100 kgm -3 The process that is more than ideal. Claim 5 In any one of claims 1 to 4, the mass of the plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​the one or more stirring surfaces, and 750 kg m² -2 Below, preferably 500 kg m -2 Below, more preferably 400 kg m -2 Below, most preferably 300 kg m -2 A process that is less than or equal to the following. Claim 6 In any one of claims 1 to 5, the mass of the plurality of porous particles contained in the internal volume during stirring depends on the surface area of ​​the one or more stirring surfaces, and 1 kg m² -2 Ideally, 3 kg m² -2 Ideally, 5 kg m² -2 Ideally, most preferably 10 kg m -2 The process that is more than ideal. Claim 7 In any one of claims 1 to 6, the one or more stirring surfaces are 0.002 to 0.08 m during stirring. 3 s -1 kg -1 , preferably 0.003 to 0.06 m 3 s -1 kg -1 , more preferably 0.004 to 0.04 m 3 s -1 kg -1 , most preferably 0.005 to 0.02 m 3 s -1 kg -1 A process that passes through a volume per second that varies depending on the mass of the plurality of porous particles contained in the internal volume of the above. Claim 8 A process according to any one of claims 1 to 7, wherein the gap between the stirring member and the inner surface of the outer wall is less than 5%, preferably less than 2%, and most preferably less than 1% of the internal dimensions of the reactor measured along the gap direction. Claim 9 In any one of claims 1 to 8, the gap between the stirring member and the inner surface of the outer wall varies according to the size of the plurality of porous particles provided in the reactor, D 50 In the case of porous particles with a particle diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10% of the internal dimensions of the reactor measured along the gap direction, and D 50 In the case of porous particles with a particle diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 3% of the internal dimensions of the reactor measured along the gap direction, or D 50 A process in which, for porous particles with a particle diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 2% of the internal dimensions of the reactor measured along the gap direction. Claim 10 A process according to any one of claims 1 to 9, wherein the gap between the stirring member and the inner surface of the outer wall is 15 cm or less, preferably 5 cm or less, more preferably 2 cm or less, more preferably 1 cm or less, more preferably 5 mm or less, and most preferably 2 mm or less. Claim 11 In any one of claims 1 to 10, the gap between the stirring member and the inner surface of the outer wall varies according to the size of the plurality of porous particles provided in the reactor, D 50 In the case of porous particles with a particle diameter exceeding 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 150 mm, and D 50 In the case of porous particles with a particle diameter in the range of 30 μm to 200 μm, the gap between the stirring member and the inner surface of the outer wall is less than 50 mm, or D 50 A process in which, for porous particles with a particle diameter of less than 30 μm, the gap between the stirring member and the inner surface of the outer wall is less than 10 mm. Claim 12 In any one of claims 1 to 11, the plurality of porous particles are D which is 0.01% or more of the nearest gap between the stirring member and the inner surface of the outer wall. 50 It has a particle diameter, and more preferably D 50 A process in which the particle diameter is 0.05% or more, more preferably 0.1% or more, more preferably 0.5% or more, more preferably 1% or more, and most preferably 2% or more of the gap between the stirring member and the inner surface of the outer wall. Claim 13 In any one of claims 1 to 12, the plurality of porous particles are D 50 A process having a particle diameter of less than 200 μm, preferably less than 100 μm, more preferably less than 50 μm. Claim 14 In any one of claims 1 to 13, the plurality of porous particles are D 50 A process having a particle diameter in the range of 0.5 μm to 200 μm, preferably in the range of 1 μm to 30 μm, more preferably in the range of 2 μm to 10 μm. Claim 15 A process according to any one of claims 1 to 14, wherein the plurality of porous particles have a D1 particle diameter of at least 0.1 μm, preferably at least 0.5 μm, more preferably at least 1 μm, more preferably at least 1.5 μm. Claim 16 In any one of claims 1 to 15, the plurality of porous particles are D 10 A process having a particle diameter of at least 0.2 μm, preferably at least 0.5 μm, more preferably at least 1 μm, more preferably at least 1.5 μm, more preferably at least 2 μm, and more preferably at least 3 μm. Claim 17 In any one of claims 1 to 16, the plurality of porous particles are D 90 A process having a particle diameter of 250 μm or less, preferably 150 μm or less, more preferably 100 μm or less, more preferably 50 μm or less, and more preferably 30 μm or less. Claim 18 In any one of claims 1 to 17, the plurality of porous particles are D 98 A process having a particle diameter of 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, more preferably 50 μm or less, and more preferably 30 μm or less. Claim 19 In any one of claims 1 to 18, the plurality of porous particles A process in which the span defined as is is 5 or less, preferably 4 or less, more preferably 3 or less, more preferably 2 or less, and more preferably 1.5 or less. Claim 20 A process according to any one of claims 1 to 19, wherein the plurality of porous particles exhibit positive skewness in a volume-based particle diameter distribution. Claim 21 In any one of claims 1 to 20, D of the plurality of porous particles 50 A process in which the diameter is smaller than the volume-based average particle diameter. Claim 22 In any one of claims 1 to 21, the skewness of the particle diameter distribution of the plurality of porous particles (Malvern Mastersizer TM A process in which (measured by an analyzer) is 4 or less, preferably 3 or less, more preferably 2 or less, more preferably 1.5 or less. Claim 23 In any one of claims 1 to 22, the skewness of the particle diameter distribution of the plurality of porous particles (Malvern Mastersizer TM A process in which (measured by an analyzer) is at least 0.2, preferably at least 0.3, more preferably at least 0.

4. Claim 24 In any one of claims 1 to 23, the plurality of porous particles belong to Geldart Group A, and preferably, the one or more stirring surfaces are 0.001 to 0.005 m during stirring. 3 s -1 kg -1 A process capable of passing through a volume per second. Claim 25 In any one of claims 1 to 24, the plurality of porous particles belong to Geldart Group C, and preferably, the one or more stirring surfaces are 0.005 to 0.1 m during stirring. 3 s -1 kg -1 A process capable of passing through a volume per second. Claim 26 A process according to any one of claims 1 to 25, wherein the stirring member moves through 5% to 90%, preferably 10% to 80%, more preferably 20% to 70%, and most preferably 30% to 60% of the internal volume during stirring. Claim 27 A process according to any one of claims 1 to 26, wherein the one or more stirring surfaces are provided over 50% to 100% of the outer wall length, preferably over at least 60% to 90% of the outer wall length, and more preferably over 60% to 80% of the outer wall length. Claim 28 A process according to any one of claims 1 to 27, wherein stirring the plurality of porous particles comprises rotating a stirring member located in the internal volume around the central axis of the internal volume. Claim 29 In paragraph 28, the process wherein the internal volume has substantially continuous rotational symmetry about a central axis. Claim 30 A process according to claim 28 or 29, wherein the stirring member forms a center open around a central axis. Claim 31 A process according to claim 30, wherein the open center radius of the stirring member is 10% to 90%, preferably 15% to 80%, more preferably 20% to 70%, even more preferably 25% to 60%, and most preferably 30% to 50% of the distance between the center axis and the outer wall. Claim 32 A process according to any one of claims 1 to 31, wherein each stirring surface is an area of ​​a stirring member that forms an angle of inclination with respect to a gravity vector during stirring, and is arranged to lift the plurality of porous particles opposite to the direction of the gravity vector as the stirring surface moves through the plurality of porous particles. Claim 33 A process according to claim 32, wherein each stirring surface forms an angle of 20° to 80°, preferably 30° to 70°, more preferably 40° to 60° with respect to the gravity vector during stirring, and / or is an area of ​​a stirring member forming an angle greater than 45° with respect to the gravity vector during stirring. Claim 34 A process according to any one of claims 1 to 33, wherein the stirring member comprises a helical stirring surface, preferably comprises at least two separated helical stirring surfaces, and more preferably comprises at least three separated helical stirring surfaces. Claim 35 A process according to any one of claims 1 to 34, wherein the gas is introduced into the internal volume of the reactor through a plurality of inlets leading to the internal volume, wherein the plurality of inlets are arranged such that the flow rate of the gas introduced into the internal volume per unit area in a plane perpendicular to the central axis of the internal volume increases as it moves from the central axis toward the outer wall. Claim 36 A process according to any one of claims 32 to 35, wherein the gas is introduced into the internal volume of the reactor through a plurality of inlets penetrating the outer wall, and the plurality of inlets penetrating the outer wall are arranged such that the flow rate of the gas introduced into the internal volume per unit area of ​​the outer wall decreases along the outer wall in a direction opposite to the direction of the gravity vector. Claim 37 A process according to any one of claims 1 to 36, wherein the gas is introduced into the internal volume of the reactor through a plurality of inlets located in the stirring member, preferably the plurality of inlets are arranged such that the flow rate of the gas introduced into the internal volume decreases along the stirring member, and most preferably decreases in a direction opposite to the direction of the gravity vector. Claim 38 A process according to any one of claims 1 to 37, wherein during step (c), the pressure within the internal volume is at least 100 kPa, preferably at least 200 kPa, more preferably at least 300 kPa, more preferably at least 500 kPa, more preferably at least 650 kPa, more preferably at least 750 kPa, more preferably at least 1000 kPa, more preferably at least 1500 kPa, more preferably at least 2000 kPa, more preferably at least 2500 kPa, more preferably at least 3000 kPa. Claim 39 A process according to any one of claims 1 to 38, wherein during step (c), the pressure within the internal volume is 6000 kPa or less, more preferably 5000 kPa or less, more preferably 4000 kPa or less, more preferably 3000 kPa or less, more preferably 2000 kPa or less, more preferably 1600 kPa or less, more preferably 1500 kPa or less, more preferably 1200 kPa or less, more preferably 1000 kPa or less, more preferably 900 kPa or less, more preferably 800 kPa or less, more preferably 700 kPa or less, more preferably 650 kPa or less, more preferably 600 kPa or less, more preferably 300 kPa or less. Claim 40 A process according to any one of claims 1 to 39, wherein during step (c), the temperature within the internal volume is within the range of 350 to 500°C, preferably 350 to 450°C, 360 to 430°C, 370 to 420°C, or 370 to 400°C. Claim 41 A process according to any one of claims 1 to 40, wherein the gas is substantially continuously introduced into the internal volume during step (c), and / or the exhaust gas is preferably substantially continuously discharged from the internal volume during step (c). Claim 42 In any one of claims 1 to 41, the process comprises, after step (c) (d), grinding the plurality of particles to D 50 A process further comprising a step of reducing particle diameter. Claim 43 In paragraph 42, D of the porous particles provided in step (a) 50 The particle diameter is at least 20 μm, preferably at least 30 μm, more preferably at least 40 μm, more preferably at least 50 μm, more preferably at least 100 μm, and step (d) is to grind the plurality of particles to D 50 A process comprising reducing the particle diameter to less than 20 μm, preferably less than 10 μm, more preferably less than 5 μm. Claim 44 A composition comprising or made of silicon-containing composite particles obtainable by a process described in any one of claims 1 to 43. Claim 45 An electrode comprising silicon-containing composite particles obtainable by a process described in any one of claims 1 to 41. Claim 46 A rechargeable metal-ion battery comprising the electrodes described in paragraph 45.

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