Nano-sized powder advanced materials, their production and use

Abstract

This disclosure describes a method and apparatus for producing advanced nanoscale powder materials that addresses at least some of the known challenges relating to scale feasibility, sustainability, and quality inherent in prior art methods and apparatus. Nanoscale powders having advantageous chemical and / or physical properties that can be used in a variety of applications are also described. The nanoparticle production apparatus includes a feed mechanism for supplying a fluid precursor material along a feed channel to a reaction zone, a plasma apparatus configured to generate a plasma jet in the reaction zone, the plasma jet colliding with the precursor material at the convergence point of the plasma jet streamlines and the feed channel to produce a reactant gas mixture, the plasma apparatus, and a cooling zone that receives the reactant gas mixture to promote nucleation and produce nanoparticles.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the interests of U.S. Provisional Patent Application No. 63 / 079,820, filed September 17, 2020; No. 62 / 913,009, filed October 9, 2019; No. 62 / 913,001, filed October 9, 2019; No. 62 / 913,025, filed October 9, 2019; No. 62 / 932,544, filed November 8, 2019; No. 62 / 932,557, filed November 8, 2019; and No. 62 / 932,562, filed November 8, 2019. The contents of all of the above documents are incorporated herein by reference.

[0002] This disclosure, as a whole, relates to the field of advanced nano-sized powder materials that can be used in energy-related applications. [Background technology]

[0003] Silicon-containing advanced nanoscale powder materials have been proposed as solutions for several energy-related applications, including photovoltaic technology, battery technology, and thermoelectric technology. In lithium-ion battery applications, silicon-containing advanced powder materials are proposed as an alternative to state-of-the-art graphite materials because silicon's high lithium storage capacity (approximately 10 times higher in mass compared to graphite) enables the development of high-capacity anodes. However, bulk silicon rapidly degrades due to the rapid expansion and contraction of its volume when storing and releasing lithium. These changes are thought to induce contact losses in the electron conduction network with the electrode material and / or damage to the electrode material particles. As a result, battery capacity decreases, and consequently, lifespan is shortened. Nanoscale silicon-containing advanced powder materials, for example, when the average particle size of nanoscale particles is less than 300 nanometers, improve the cycle performance of the resulting anode by assisting in the control of volume and stress changes.

[0004] Despite the advantageous properties obtained by using nano-sized silicon-containing advanced powder materials, the production of high-purity nano-sized silicon-containing advanced powder materials for such applications remains costly, inefficient, and lacks large-scale feasibility.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Means for Solving the Problems

[0006] This summary is provided to introduce a simplified selection of concepts that are further described in the following detailed description. This summary is not intended to identify key or essential aspects of the subject matter of the invention recited in the claims.

[0007] This disclosure describes methods and apparatuses for producing advanced nano-sized powder materials that address at least some of the known problems related to large-scale feasibility, continuity, and quality inherent in prior art methods and apparatuses. Nano-sized powders having advantageous chemical and / or physical properties for various applications are also described.

[0008] As embodied and broadly described herein, this disclosure relates to nanoparticles, wherein the particle size distribution of the nanoparticles is from 20 nm to 150 nm, and the number of particles larger than 1000 nm is less than 10 ppm by number.

[0009] As embodied and extensively described herein, this disclosure relates to nanoparticles in which the doping agent content is substantially uniform along the radial distribution of the nanoparticles.

[0010] As embodied and extensively described in the specification, the disclosure relates to nanoparticles having a core, wherein the nanoparticles have a silicon alloy in the core, and the alloy consists of silicon and elements having a substantially uniform radial distribution in the core.

[0011] As embodied and extensively described herein, this disclosure relates to silicon alloy nanoparticles, wherein the alloy consists of silicon and elements having a substantially uniform radial distribution in the core.

[0012] In some embodiments, the aforementioned nanoparticles may further include one or more of the following features: The particle size distribution ranges from 20 nm to 150 nm, with particles larger than 1000 nm being present in less than 10 ppm in terms of quantity. • The number of particles larger than 1000 nm is less than 0.5 ppm. The number-average particle diameter D50 is 100 nm or less, and the volume-average particle diameter D50 is 300 nm or less. The volume-average particle diameter D90 is 700 nm or less, preferably 600 nm or less. The volume-average particle diameter D95 is less than 1000 nm, preferably less than 700 nm. The number-average particle size D10 is 60 nm or less, preferably 40 nm or less. • The number-average particle size D50 is 100 nm or less. • The number-average particle size D90 is 200 nm or less. Particles with an average particle diameter exceeding 300 nm account for less than 1.5% in number and less than 30% in volume / mass. • Does not contain particles with an average particle diameter exceeding 10 μm. The core is made of silicon, germanium, gallium, or SiGe y This includes, where y ranges from 0 to 1. The purity of the silicon is at least 99.95%. The core contains either single-crystal silicon or polycrystalline silicon. The core contains n-doped silicon or p-doped silicon. • Core is SiN x The alloy contains a nitride layer, where x ranges from 0 to 1. • Nearly stoichiometric SiN x The nitrogen content of the nanoparticles is substantially uniform throughout the entire core forming the alloy. The thickness of the nitride layer is approximately 0.06 to approximately 2.0 nm, preferably less than 0.5 nm. •SiO x And OHCl surface species are not included, where x is between 0 and 1. The passivation layer is either an oxide layer or a nitride layer. The thickness of the oxide layer is approximately 0.3 nm to 1.0 nm. The thickness of the nitride layer is approximately 0.06 to approximately 2.0 nm, preferably less than 0.5 nm. • Contains less than 1000 ppm of carbon. • Contains less than 1500 ppm of nitrogen.

[0013] As embodied and extensively described herein, the disclosure relates to a nanoparticle manufacturing apparatus comprising a supply mechanism for supplying a fluid precursor material along a supply channel to a reaction region, a plasma apparatus configured to generate a plasma jet in the reaction region, the plasma jet colliding with the precursor material at the convergence point of the plasma jet streamlines and the supply channel to produce a reactant gas mixture, the plasma jet streamlines forming an angle with respect to the supply channel, and a cooling region receiving the reactant gas mixture to promote nucleation and produce nanoparticles.

[0014] As embodied and extensively described herein, the disclosure relates to a nanoparticle manufacturing apparatus comprising a supply mechanism for supplying a fluid precursor material along a supply channel to a reaction region, a plasma apparatus configured to generate a plasma in the reaction region, the plasma in contact with the precursor material to produce a reactant gas mixture, a reaction chamber including a reaction region, the reaction chamber having a longitudinal axis, the apparatus configured to inject a preheated gas to generate a radial preheated gas flow in the reaction chamber along at least a portion of the longitudinal axis, and a cooling region to receive the reactant gas mixture to promote nucleation and produce nanoparticles.

[0015] As embodied and extensively described herein, the disclosure relates to a method for producing nanoparticles, comprising the steps of: supplying a fluid precursor material along a supply channel to a reaction region; generating a plasma jet in the reaction region; and bringing the precursor material into contact with the plasma jet, wherein the plasma jet collides with the precursor material at the convergence point of the plasma jet's streamlines and the supply channel to produce a reactant gas mixture, the plasma jet's streamlines forming an angle with respect to the supply channel; and cooling the reactant gas mixture in a cooling region to promote nucleation and produce nanoparticles.

[0016] As embodied and extensively described herein, the disclosure relates to a method for producing nanoparticles, comprising the steps of: supplying a fluid precursor material along a supply channel to a reaction region, the reaction region being located in a reaction chamber having a longitudinal axis; generating a plasma in the reaction region, the plasma contacting the precursor material to produce a reactant gas mixture; injecting a preheated gas to generate a radial preheated gas flow in the reaction chamber along at least a portion of the longitudinal axis; and cooling the reactant gas mixture in a cooling region to promote nucleation and produce nanoparticles.

[0017] In some embodiments, the methods and apparatus described above may further include one or more of the following features: A supply mechanism including a long structure supplies fluid precursor material to the assembly point, and the long structure defines channels for receiving the precursor. The channel has an outlet end, and the collection point is located downstream of the outlet end along the supply path. The supply mechanism includes multiple elongated structures for supplying fluid precursor material to the collection point. The supply mechanism includes multiple elongated structures arranged continuously along the longitudinal axis of the reaction region. The feeding mechanism includes multiple elongated structures arranged around the longitudinal axis of the device. The plasma apparatus includes a nozzle with an outlet for releasing a plasma jet into the reaction zone. Plasma jets are generated from gases including argon, helium, or combinations thereof. The gas further includes hydrogen, oxygen, nitrogen, or any combination thereof. The supply mechanism further supplies carrier gas into the reaction zone. The carrier gas is mixed with the precursor material before, simultaneously with, or after the precursor material is injected into the reaction zone. The carrier gas may include argon, helium, or a combination thereof. The carrier gas further includes hydrogen, oxygen, nitrogen, or any combination thereof. The supply mechanism is configured to control the concentration of the precursor material in the reaction zone by adjusting the relative flow rate of the carrier gas. The reactant gas mixture contains precursor materials in dissociated or chemically transformed forms. The supply mechanism further supplies additive gases or doping agents to the reaction zone, the cooling zone, or both. • The additive gas or doping agent is mixed with the precursor material before, simultaneously with, or after the precursor material is injected into the reaction zone. • The added gas or doping agent creates a passive layer on the nano-sized particles. • The added gas or doping agent contains oxygen-containing molecules, nitrogen-containing molecules, or carbon-containing molecules. • The added gas or doping agent includes H2O, CO2, N2, NH3, CH4, or C2H2. • The added gas or doping agent contains molecules containing Mendeleev Group III, Group IV, or Group V elements. • The added gas or doping agent contains Ga2H3, ArH3, B2H6, and PH3. • The relative flow rate of the additive gas or doping agent is adjusted to control the concentration of the additive gas or doping agent in the reaction zone, the cooling zone, or both. The angle of the plasma jet streamlines relative to the supply path angle is between about 10° and about 80°, preferably between 10° and about 60°, more preferably between about 10° and about 30°, and even more preferably between about 15° and about 20°. The plasma apparatus includes a nozzle with an outlet, and the plasma jet is emitted from the outlet into the reaction area. The reaction area is contained within a reaction chamber having a longitudinal axis. • A gas is injected to generate a radial gas flow within the reaction chamber along at least a portion of the longitudinal axis. The temperature of the gas that generates the radial gas flow is sufficient to extend the reaction region downstream of the collection point and to produce an additional amount of reactant gas mixture from the precursor material present downstream of the collection point. The gas that generates the radial gas flow contains oxygen-containing molecules, nitrogen-containing molecules, or carbon-containing molecules. The gas that generates the radial gas flow includes Ar, N2, or He. • The radial gas flow prevents reactants in the gaseous mixture from reaching the inner wall of the reaction chamber. • The relative flow rate of the gas that generates a radial gas flow is adjusted to control the dilution of the seed during the nanoparticle generation stage. • The degree of crystallinity of nanoparticles is controlled by adjusting the temperature of the gas that generates the radial gas flow. • Nanoparticles may have a single-crystal structure, a polycrystalline structure, a structure including a crystallized region with an amorphous region in between, or a core-shell shape in which the core has a crystalline structure and the amorphous layer completely encloses the core. The gas that generates the radial gas flow flows through a diffusion wall located within the reaction chamber, which is sandwiched between the outer wall and the porous inner wall of the reaction chamber, forming a radial gas flow. The diffusion wall is an additional diffusion outlet located within the reaction chamber, sandwiched between the outer wall and the porous inner wall of the reaction chamber, and includes an additional diffusion outlet at the top of the reaction chamber, which is configured to inject at least a portion of the gas that generates a radial gas flow into a region near the collection point of the reaction chamber. • The porous inner wall is made from a porous heat-resistant material. Porous heat-resistant materials include metal or ceramic materials. The diffusion wall includes multiple openings through which the gas that generates a radial gas flow can pass. The cooling area is located within the cooling chamber, which is in fluid communication with the reaction area. The chamber is located downstream of the cooling area. The gaseous mixture flowing from the reaction chamber is cooled in a cooling chamber to a temperature at which the reaction is substantially stopped. The cooling chamber includes an injection module configured to inject cooling gas into the cooling chamber. • The cooling gas prevents nanoparticles from adhering to the inner wall of the cooling chamber. • Control the temperature and / or flow rate of the cooling gas. The injection module is configured to (i) inject a cooling gas along the longitudinal direction of the cooling chamber to form a longitudinal gas, (ii) inject a cooling gas to form a radial cooling gas in the cooling chamber, or (iii) to do both (i) and (ii). The longitudinal gas and the radial cooling gas are the same gas. • Longitudinal gas and radial cooling gas are different gases. The cooling gas contains a nanoparticle growth inhibitor. The injection module is a first injection module consisting of multiple injection modules for injecting corresponding cooling gases. • Nanoparticles are recovered from the cooling area into a powder recovery machine, which is configured to recover the nanoparticles by gravity. The powder recovery unit is located downstream of the cooling area. • The powder recovery machine includes a cyclone. • The cyclone separates the nanoparticles into two or more classifiers according to their size. • Nanoparticles are recovered from the cooling area into the powder recovery machine, where they move from the cooling area to the powder recovery machine in directions other than the vertical. • Nanoparticles are transported from the cooling area to the powder recovery machine through a conduit, and the powder recovery machine is in fluid communication with the cooling area via the conduit. • Nanoparticles are transported through the conduit by creating a flow of a gaseous medium through the conduit. • Nanoparticles are recovered from the cooling area into a powder recovery machine, which includes a cyclone. The plasma of the plasma jet is generated at a power level between 5 and 450 kW, preferably around 80 kW. • The majority of nanoparticles are composed of spherical particles. The precursor material contains Si, Ge, or Ga and a group III element-containing molecule. • Si-containing molecules include silane, trichlorosilane, or silicon tetrachloride. • Nanoparticles are manufactured at a rate of at least 1 kg / hour, preferably from 1 kg / hour to 3 kg / hour. • The plasma jet is a primary plasma jet consisting of multiple plasma jets. The plasma device is either a direct current (DC) plasma torch or an inductively coupled plasma (ICP) torch.

[0018] As embodied and extensively described herein, the disclosure also relates to a lithium secondary battery comprising at least an anode, a cathode, and an electrolyte, wherein the anode comprises nanosized particles of silicon or an alloy thereof, and the charge capacity in the first 50 charge and / or discharge cycles of the battery remains within 80% of the initial charge capacity value.

[0019] As embodied and extensively described herein, the disclosure also relates to a lithium secondary battery comprising at least an anode, a cathode, and an electrolyte, wherein the anode comprises nanosized particles of silicon or an alloy thereof, and the charge capacity in the first 100 charge and / or discharge cycles of the battery remains within 80% of the initial charge capacity value.

[0020] As embodied and extensively described herein, the disclosure also relates to an anode electrode for a lithium secondary battery, the anode electrode comprising nanosized particles of silicon or an alloy thereof, and having a charging capacity of 2000 mAh / g or more.

[0021] All features of typical embodiments described herein, which are not mutually exclusive, can be combined with each other. Elements of one embodiment can be used in other embodiments without further mention. Other aspects and features of the present invention will become apparent to those skilled in the art by considering the following description of specific embodiments in conjunction with the accompanying drawings.

[0022] A detailed description of a specific typical embodiment is provided below, with reference to the attached drawings. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows a cross-sectional view of a nano-sized powder manufacturing apparatus. [Figure 2] This figure shows a cross-sectional view of a plasma generation device to be used in conjunction with the apparatus shown in Figure 1. [Figure 3] This figure shows a cross-sectional view of the upper part of the apparatus shown in Figure 1, including the plasma generator, reaction chamber, and part of the cooling chamber. [Figure 4] This figure shows various crystal structures of nano-sized particles. [Figure 5] This figure shows a cross-sectional view of the outlet of the injector used to inject the precursor material into the apparatus shown in Figure 1. [Figure 6] This figure shows a cross-sectional view of the outlet of the injector used to inject the precursor material into the apparatus shown in Figure 1. [Figure 7A] This figure shows a cross-sectional view of an embodiment relating to the reaction chamber, including the high-temperature wall region of the apparatus shown in Figure 1. [Figure 7B] This figure shows a cross-sectional view of an embodiment relating to the reaction chamber, including the high-temperature wall region of the apparatus shown in Figure 1. [Figure 8] This figure shows a cross-sectional view of the cooling area of ​​a cooling chamber for use with the apparatus shown in Figure 1. [Figure 9] This figure shows an illustration of the assembly, including the device shown in Figure 1. [Figure 10] This figure shows a graph illustrating the effect of the dynamic high-temperature wall gas temperature (K) on the conversion rate (%) of silane. [Figure 11] This figure shows a graph illustrating the effect of the injector sheath gas flow rate (liters per minute) on the silane conversion rate (%). [Figure 12] This figure shows a graph illustrating the effect of the injector sheath gap (mm) on the silane conversion rate (%). [Figure 13] This figure shows a graph illustrating the effect of the type of injector on the conversion rate (%) of silane. [Figure 14A] This figure shows the XRD peak shape of the first powder (BET=12.14m2 / g)(dp=212nm)(O%=0.20)(C%=0.066)(N%=1.200)(H%=0.020). [Figure 14B] Figure 14A shows a scanning electron microscope (SEM) image of the powder. [Figure 15A] This figure shows the XRD peak shape of the second powder (BET=23.25m2 / g)(dp=111nm)(O%=1.20)(C%=0.030)(N%=0.550)(H%=0.020). [Figure 15B] Figure 15A shows an SEM image of the powder. [Figure 16A] This figure shows the XRD peak shape of the third powder (BET=49.4m2 / g)(dp=52nm)(O%=2.10)(C%=0.029)(N%=0.360)(H%=0.038). [Figure 16B]Figure 16A shows an SEM image of the powder. [Figure 17A] This is a SEM image of silicon powder produced using silane as a precursor material. [Figure 17B] This is a SEM image of silicon powder produced using silane as a precursor material. [Figure 17C] This is a SEM image of silicon powder produced using silane as a precursor material. [Figure 18A] This figure shows an SEM image of silicon powder (BET=32.38m2 / g) (dp=80nm) (O%=1.35) (N%=4.00) produced by the prior art plasma torch method using micron-sized silicon precursor material. [Figure 18B] This figure shows an SEM image of silicon powder (BET=32.38m2 / g) (dp=80nm) (O%=1.35) (N%=4.00) produced by the prior art plasma torch method using micron-sized silicon precursor material. [Figure 19] Figures 18A and 18B show graphs of the particle size distribution (PSD) (in μm units) at the volume density (%) of the powder. [Figure 20] Figures 18A and 18B show graphs of the PSD (particle size in μm units) at the number density (%) of the powder. [Figure 21A] This figure shows an SEM image of silicon powder (BET=31.04m2 / g) (dp=83nm) (O%=1.80) (N%=0.75) produced using silane as a precursor material. [Figure 21B] This figure shows an SEM image of silicon powder (BET=31.04m2 / g) (dp=83nm) (O%=1.80) (N%=0.75) produced using silane as a precursor material. [Figure 22] Figures 21A and 21B show graphs of the particle size distribution (PSD) (in μm units) at the volume density (%) of the powder. [Figure 23] Figures 21A and 22B show graphs of the PSD (particle size in μm units) at the number density (%) of the powder. [Figure 24]This figure shows a relative comparison of the charging capacity behavior of a rechargeable lithium battery containing Si nanoparticle powder with a narrow particle size distribution (PSD) as the anode material, compared to a battery with a wide PSD. [Figure 25] This figure shows a relative comparison of the charging capacity behavior of rechargeable lithium batteries containing Si nanoparticle powder as the anode material, compared to micron-sized Si powder and graphite. [Figure 26] This figure shows a relative comparison of the charging capacity behavior of a rechargeable lithium battery containing SiNx composite nanoparticle powder as the anode material with that of a micron-sized Si powder with a large PSD. [Figure 27] This figure illustrates the effect of silane concentration on the average particle size. [Modes for carrying out the invention]

[0024] In the figures, embodiments are described as examples. It should be clearly understood that the description and drawings in this specification are for illustrative purposes only and are not intended to define the limitations of this disclosure.

[0025] A detailed description relating to one or more embodiments of the present invention is provided below, along with accompanying drawings illustrating the general outline of the invention. While the invention is described in relation to such embodiments, it is not limited to any embodiment. The scope of protection of the invention is limited solely by the claims. Numerous specific details are provided below to provide a full understanding of the invention. These details are provided for non-limiting examples, and the invention may be practiced in accordance with the claims without some or all of these specific details. For clarity, and to avoid unnecessarily obscuring the invention, technical elements known in the art related to the invention are not described in detail.

[0026] This disclosure describes methods and apparatus for producing advanced nanoscale powder materials that address at least some of the known challenges related to scale feasibility, sustainability, and quality inherent in prior art methods and apparatus. Nanoscale powders having advantageous chemical and / or physical properties that can be used in a variety of applications are also described.

[0027] Nano-sized powder properties The nano-sized powders of this disclosure (also referred to herein as “nanoparticles” or “nanopowder”) exhibit significant, surprising, and unexpected differences compared to powders produced using prior art evaporation processes utilizing micron-sized precursor materials (e.g., WO2018 / 157256, CA3,024,473, and US7,572,315, all of which are incorporated herein by reference, respectively). For example, the nanoparticle powders described herein have a more uniform particle size and a narrower particle size distribution (PSD), whereas powders produced using such prior art evaporation processes have a much broader PSD and consist mostly of large and extra-large micron particles, which are undesirable in many applications. Furthermore, compared to powders produced using prior art evaporation processes, the nanoparticle powders described herein allow for better control / adjustment of doping. Such control / adjustment of doping allows for more flexible realization of desired properties in the powder for a variety of applications.

[0028] In some embodiments, the nanoparticle powder has a spherical or nearly spherical appearance, and the powder can be discrete or partially aggregated to varying degrees, depending essentially on the operating conditions used during its manufacture. Surface modifications such as oxidation, nitriding, or carbonization can be applied to the nanoparticle powder.

[0029] In some embodiments, PSD can be achieved without requiring a classification step after plasma treatment. Such PSD is strictly controlled, for example, so that the particle size is biased towards smaller sizes rather than larger sizes, contrary to those obtained by known methods in the art. Not only are there technical advantages to obtaining such smaller sizes (as described elsewhere in this text), but there are also economic advantages, such as a lower yield, as the size of the nanoparticles obtained from the manufacturing process is less coarse, resulting in less waste material (material that does not meet the cutoff classification value). The powder may have an average PSD in which at least 80% of the particles are smaller than 150 nm, for example, at least 85%, 90%, 95%, or 99% of the particles are smaller than 150 nm.

[0030] Nanoparticle powders may include one or more of the following particle size characteristics: PSD within the range of 20nm to 350nm, 20nm to 300nm, 20nm to 200nm, or 20nm to 150nm, or any range within those ranges; D90≦200nm, D90≦150nm, or D90≦130nm; median diameter (D50) of 120nm or less; median diameter (D50) of 100nm or less; median diameter (D50) of 80nm or less; or median diameter (D50) of 50nm or less; 30nm D50 (number) between m and 120 nm, or between 40 nm and 100 nm, or between 50 nm and 80 nm, or about 60 nm; D99 ≤ 250 nm, or D99 ≤ 230 nm, showing less than 100 ppm, less than 10 ppm, less than 1 ppm, or less than 0.5 ppm of particles larger than 350 nm; agglomerated particles less than 100 ppm, agglomerated particles less than 50 ppm, agglomerated particles less than 25 ppm, agglomerated particles less than 10 ppm, agglomerated particles less than 1 ppm, or in some embodiments, no detectable agglomerated particles.

[0031] The particle size characteristics of a particulate composition can be determined using techniques known in the art, including but not limited to laser diffraction spectroscopy, transmission electron microscopy, and scanning electron microscopy (SEM). The SEM image is an image of a given region of the composition under analysis, which varies at least depending on the D50 of the composition to ensure accuracy and / or statistical significance. For example, a D50 of 120 nm may require a region of composition with 5 μm per 5 μm, a D50 of 80 nm may require a region of composition with 3 μm per 3 μm, and a D50 of 50 nm may require a region of composition with 2 μm per 2 μm. The powders disclosed herein contain fewer than three particles having a size greater than 1 μm when measured with a 5000x SEM image of the composition, fewer than two particles having a size greater than 1 μm when measured with a 5000x SEM image of the composition, or contain or do not contain one detectable particle having a size greater than 1 μm when measured with a 5000x SEM image of the composition, contain fewer than three particles having a size greater than 650 nm in a 5000x SEM image of the composition, or have a size greater than 1 μm when measured with a 5000x SEM image of the composition The composition may have the following characteristics: it contains fewer than two particles of a certain size, or contains or does not contain one detectable particle larger than 1 μm when measured with a 5000x magnification SEM image of the composition; it contains fewer than three particles larger than 350 nm in a 5000x magnification SEM image of the composition; it contains fewer than two particles larger than 1 μm when measured with a 5000x magnification SEM image of the composition, or it contains or does not contain one detectable particle larger than 1 μm when measured with a 5000x magnification SEM image of the composition.

[0032] In some embodiments, nanoparticle powders can incorporate doping elements in a more controlled manner compared to powders produced using prior art evaporation processes. For example, the dispersion of the doping agent can be made more uniform, allowing for greater flexibility in the doping agent content in the nanoparticle powder and greater stability in the thickness of the passive layer of the nanoparticle powder. Better control over doping to nanoparticle powders allows for greater flexibility in tuning other properties of the nanoparticle powders for specific applications.

[0033] In some embodiments, the nanoparticle powder may incorporate a doping agent not exceeding 4%, for example, not exceeding 3%, not exceeding 1.5%, or not exceeding 0.75%. Examples of doping agents are further described elsewhere in this text.

[0034] Apparatus and method for producing nano-sized powders The nano-sized powders described herein may be produced using a method of evaporating and / or reacting a fluid precursor material to obtain a reactant gas mixture. Methods and apparatus are described that allow for the control of the temperature and residence time of the precursor material in the reaction zone to sufficiently evaporate and / or react the precursor to form a desired chemical composition in the resulting nano-sized powder. Methods are also described for controlling the cooling rate of the reactant gas mixture to obtain nano-sized powders having desired characteristics with respect to particle size, as described herein.

[0035] Figures 1 to 3 show detailed front views of an apparatus 100 for producing nano-sized particle powder by evaporation and / or reaction of a precursor material 130 (sometimes referred to as “raw material” or “core precursor”). The apparatus 100 may include a plasma generator 120 for generating plasma 112, a reaction chamber 140, and a cooling chamber 500 (defining a “quenching zone” or “quenching section”). The apparatus 100 further includes a powder recovery unit 600. The apparatus 100 includes other components such as housings, flanges, bolts, etc., which are considered to require no further explanation and are not further described herein.

[0036] The plasma generator 120 shown in Figures 1 to 3 is an inductively coupled plasma (ICP) torch, more specifically a radio frequency (RF) inductively coupled plasma torch. Examples of ICP torches include the PL-50, PN-50, PL-35, PN-35, PL-70, PN-70, or PN-100, which are commercialized by TEKNA Plasma Systems. In some embodiments, the plasma generator 120 may be a different type of plasma torch, such as a direct current (DC) plasma torch (commercialized by companies such as Praxair, Oerlikon-Metco, Pyrogenesis, and Northwest Mettech).

[0037] The plasma generator 120 includes an outer cylinder torch body 181, an inner cylinder plasma confinement tube 110, and at least one induction coil 126 arranged coaxially. The outer cylinder torch body 181 may be manufactured from a moldable composite material, such as a moldable composite ceramic material. The inner cylinder plasma confinement tube 110 may be manufactured from a ceramic material and is coaxial with the torch body 181. The induction coil 126 is coaxial with the torch body 181 and embedded in the torch body 181 to generate an RF (radio frequency) electromagnetic field, which ignites and maintains the plasma 112 confined in the plasma confinement tube 110 by the energy of the RF electromagnetic field.

[0038] The plasma is generated from a plasma center gas 20 such as argon and / or helium, and may further contain hydrogen, oxygen, nitrogen, or any combination thereof. The plasma center gas 20 is typically supplied into the plasma containment tube 110 through the head 185 of the plasma generator 120 at the upper end of the torch body 181. RF current is supplied to the induction coil 126 via power leads (not shown). The plasma center gas 20 may be introduced into the plasma generator 120 such that its flow is coaxial with the torch body 181. Alternatively, the plasma center gas 20 may be introduced into the plasma generator 120 such that its flow is at an angle to the torch body 181.

[0039] The apparatus 100 may be configured to inject at least one type of plasma sheath gas 40 at one or more locations downstream or upstream within the plasma containment tube 110. For example, as shown in Figure 3, the head 185 includes an inlet for the plasma center gas 20 and an adjacent inlet for the plasma sheath gas 40. The plasma sheath gas 40 can stabilize the plasma emission at the center of the tube and protect the plasma containment tube 110 from the high-temperature flux generated by the plasma emission. In some implementations, the plasma 112 may be generated from the plasma center gas 20 alone or from both the plasma center gas 20 and the plasma sheath gas 40. The plasma sheath gas 40 may be any plasma sheath gas known in the art. In some embodiments, the plasma sheath gas includes argon, hydrogen, or a mixture thereof.

[0040] The plasma generator 120 is in fluid communication with the reaction chamber 140 through the outlet shown in Figure 2A or through the outlet nozzle shown in Figure 2B. The nozzle may be formed from a water-cooled metal, a radiative-cooled heat-resistant material, or a combination thereof, without limitation. For example, the nozzle may include a single outlet, such as a central opening, and be configured to generate a single plasma jet. Alternatively, the nozzle may include multiple outlets, such as radial openings, e.g., microplasma jet channels, to generate a corresponding number of plasma jets. Alternatively, the nozzle may include both such a central opening and multiple radial openings. The multiple radial openings may be arranged in the nozzle at equal angles to each other. The radial openings may be designed to direct each fraction of the plasma into the reaction chamber 128 to generate a plasma jet 112. The number of radial openings and their elevation angles relative to the geometric longitudinal axis of the center of the plasma head 185 may be selected as a function of the distribution of plasma jet streamlines around the longitudinal axis of the desired plasma torch. Examples of suitable nozzles are described, for example, in US9,718,131, all of which are incorporated herein by reference.

[0041] Device 100 includes one or more precursor injectors 1141 - 114 that inject precursor material 130 into reaction zone 128. i For example, as shown in the figure, reaction zone 128 may be installed within reaction chamber 140 downstream of plasma generation device 120. Alternatively, at least a portion of reaction zone 128 may be installed within plasma confinement tube 110 (not shown) such that one or more precursor injectors 1141 - 114 i are configured to be coaxial with torch body 181 and inject precursor material 130 into plasma 112.

[0042] When reaction zone 128 is installed downstream of plasma generation device 120, device 100 includes one or more injectors 1141 - 114 configured to inject precursor material 130 into reaction zone 128 at a convergence point that exists downstream of plasma generation device 120. i For example, device 100 may include two injectors 1141 - 114 each configured to inject precursor material 130 into reaction zone 128 at the convergence point, spaced 180° from each other. For example, device 100 may include three injectors 1141 - 114 each configured to inject precursor material 130 into reaction zone 128 at the convergence point, spaced 120° from each other. In such embodiments, regardless of the number of precursor injectors 1141 - 114 present in device 100, the injectors are configured such that the streamlines of precursor material 130 intersect at a convergence point where the streamlines of plasma 112 collide with the streamlines of precursor material 130. i For example, device 100 may include three injectors 1141 - 114 each configured to inject precursor material 130 into reaction zone 128 at the convergence point, spaced 120° from each other. In such embodiments, regardless of the number of precursor injectors 1141 - 114 present in device 100, the injectors are configured such that the streamlines of precursor material 130 intersect at a convergence point where the streamlines of plasma 112 collide with the streamlines of precursor material 130. i In such embodiments, regardless of the number of precursor injectors 1141 - 114 present in device 100, the injectors are configured such that the streamlines of precursor material 130 intersect at a convergence point where the streamlines of plasma 112 collide with the streamlines of precursor material 130. i In some embodiments, injectors 1141 - 114

[0043] In some embodiments, injectors 1141 - 114 iThese are installed at injection points that are arranged continuously along the longitudinal axis of the apparatus 100. For example, one injection point can be installed at a location in the reaction area 128 where substantially the plasma 112 is emitted, and at least another injection point can be installed at a distance downstream within the reaction chamber 140. By changing the reactant gas composition at different injection points, the composition of the nanosized powder particles can be gradually changed from the core to the shell.

[0044] In all configurations of the apparatus 100 described above, the plasma 112 heats the precursor material 130 to a temperature that enables the production of a reactant gas mixture. For example, heating occurs at the point where the collision occurs. In addition, heating may occur along the plasma afterglow 146, which is a portion of the plasma 112 below the plasma generator 120 extending along the longitudinal axis of the apparatus 100. In some embodiments, this portion of the plasma 112 extends into at least a portion of the reaction chamber 140. That is, the reaction region 128 may be extended to a point further downstream from the collision point. In addition, heating may occur further downstream in the dynamic high-temperature wall region 134, which will be described in more detail later.

[0045] The reactant gas mixture produced by the plasma is generated through a chemical change, such as the dissociation or decomposition of the precursor material 130. The precursor material 130 is injectors 1141-114 i It contains chemical elements that are injected into the apparatus 100 via and form at least a portion of the nanosized powder particles. As further described in other parts of this text, the properties of the precursors (e.g., chemical composition), their concentrations, and the operating parameters applied (e.g., temperature) may be individually selected so that the method for producing the nanosized powder is more efficient and / or the nanosized powder is of higher quality (e.g., certain properties of the nanosized powder may be improved).

[0046] In some embodiments, the precursor material 130 is used in the injectors 1141-114 iThe precursor material 130 may be mixed with a carrier gas before, simultaneously with, or after being injected into the apparatus 100. The carrier gas is typically a gas that does not react with the precursor material 130. The carrier gas may be of the same type as the plasma center gas 20 and / or may contain a gas mixture to facilitate the transport of the precursor material 130. The relative flow rate of the carrier gas may be adjusted over time to allow control of the concentration of the precursor material 130 in the reaction region 128, resulting in, for example, a heterogeneous powder composition (e.g., some particles having a first chemical composition and other particles having a second chemical composition, and the first and second chemical compositions being different). The carrier gas can stabilize the precursor material 130 before injection into the apparatus 100. In some embodiments, the carrier gas can reduce the possibility of spontaneous combustion of the precursor material 130, thereby facilitating the handling of the precursor material 130 in an industrial environment.

[0047] The reactant gas mixture may include a precursor material 130 in a dissociated or chemically transformed form, for example, the precursor material 130 may dissociate into a core radical and at least one byproduct. For example, if the precursor material 130 includes silicon or a silicon alloy precursor, the apparatus 100 includes a plasma generator 120 that generates plasma 112 at a temperature capable of producing vapor from the precursor material 130, where the vapor may contain dissociated silicon atoms.

[0048] In conventional single-probe plasma systems, as described in U.S. Patent 9,781,131, the ejection of the precursor material is coaxial with the plasma apparatus and parallel to the plasma gas flow. In such systems, the ejected precursor material, which is colder than the plasma, forms a cold region in the core of the plasma afterglow, resulting in non-uniform temperature throughout the ejection streamline. In this relatively cold region of the plasma afterglow, the precursor material cannot be completely dissociated or chemically transformed. Apparatus 100 described herein, configured such that the ejection of the precursor material 130 is "off-axis" with respect to the plasma flow 112, can advantageously mitigate this problem associated with conventional single-probe systems.

[0049] Therefore, in the device 100, the injectors 1141-114 i It is configured to be "off-axis" with respect to the plasma 112 flow. That is, injectors 1141-114 i The precursor material 130 is injected in a direction intersecting the longitudinal direction of the plasma 112 in order to minimize (or prevent) the formation of a relatively low-temperature region in the plasma afterglow of the prior art plasma device. For example, as shown in Figure 2, injectors 1141-114 i This involves injecting the precursor material 130 in a direction intersecting the longitudinal direction of the plasma 112 at an angle α that can be between approximately 10° and approximately 80°, encompassing any value within that range, such as between approximately 10° and approximately 60°, between approximately 10° and approximately 30°, or between approximately 15° and approximately 20°.

[0050] While not bound by any particular theory, injectors 1141-114 i By using an "off-axis" configuration for the probe, the injectors 1141-114 iThe fluid ejected through the injectors 1141-114 collides with the plasma 112 streamlines at an angle, thereby promoting mixing and resulting in a more uniform temperature across the ejected fluid. Therefore, the ejected precursor material 130 is thought to mix better in the plasma afterglow 146 of the plasma 112. This, in turn, allows for more uniform energy transfer from the plasma 112 to the ejected precursor material 130, significantly increasing the residence time of the reactive species through changes in their orbits in the high-temperature region, thus ensuring dissociation or chemical transformation. These advantages are also found in the injectors 1141-114. i This could also apply to any doping agents and / or additive gases sprayed through the system.

[0051] For example, in some embodiments, injectors 1141-114 i The system is configured to inject the precursor material 130 and optionally an additive gas or doping agent, exposing at least one of the afterglow region 146, the reaction region 128, or the dynamic high-temperature wall region 134 to uniform energy transfer and increased residence time as described above. This configuration increases the temperature and residence time. Therefore, those skilled in the art will see that the precursor material 130 to be injected (and optionally the injectors 1141-114) i Any additive gas / doping agent injected through the device can be exposed to a sufficiently high temperature and a sufficiently long residence time so that at least 60%, for example, at least 70%, 80%, 85%, 90%, 95%, or at least 100% of the injected precursor material 130 reacts to form a reactant gas mixture.

[0052] When producing nano-sized powder of silicon or silicon alloy, a precursor material 130 and optionally injectors 1141-114 iAny additive gas / doping agent injected through is exposed to a temperature of at least 400°C in the range of 400°C to 1400°C, for example approximately 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, or 750°C, in at least one of the afterglow 146 of the plasma 112, the reaction region 128, or the dynamic high-temperature wall region 134, for a residence time of at least 0.2 seconds, for any residence time in the range of 0.2 seconds to 1.0 seconds. For example, the temperature and residence time required to decompose 60% of SiH4 could be, for example, 637°C / 0.8 seconds, 657°C / 0.5 seconds, or 690°C / 0.2 seconds, and the temperature and residence time required to decompose 85% of SiH4 could be, for example, 670°C / 0.8 seconds, 690°C / 0.5 seconds, or 724°C / 0.2 seconds.

[0053] In some embodiments, the precursor material 130 is fluid (e.g., gas or liquid). For example, in some implementations, when producing silicon nano-sized particles, the precursor material 130 may include silane (SiH4), trichlorosilane (SiCl3H), or any mixture thereof.

[0054] Those skilled in the art will understand that the present disclosure may be extended to all molecules that may contain Group III, IV, and V elements (Mendeleev's groups as commonly referred to in the periodic table) that can react in at least one of the afterglow 146 of the plasma 112, the reaction region 128, or the dynamic high-temperature wall region 134 to form a desired reactant gas mixture, which can then be cooled to form nano-sized particles.

[0055] In some embodiments, the precursor material 130 is used in the injectors 1141-114 iBefore, simultaneously with, or after being injected into the apparatus 100 through the additive gas or doping gas or its precursor, it is mixed with the additive gas or doping gas or its precursor to produce a powder containing an alloy of elements present in the reactant gas mixture. The additive gas or doping gas or its precursor is typically a fluid (gas or liquid) that can react with the precursor material 130 and / or react at a high temperature in at least one of the afterglow 146 of the plasma 112, the reaction region 128, or the extended dynamic high-temperature wall region 134 (extending downstream of the reaction region 128), resulting in the doping agent being present in the powder particles.

[0056] In some embodiments, additive gases or doping gases or their precursors may be injected to concentrations ranging from 0 to about 5000 ppm, encompassing all values ​​within that range, for example, up to 2000 ppm, up to 1000 ppm, up to 500 ppm, up to 200 ppm, up to 100 ppm, etc. Those skilled in the art will readily understand that varying the concentration or injection position alters the distribution of additive / dope concentrations, with upstream injection promoting the penetration of additive / dope into the particle core, and downstream injection preferentially retaining the additive / dope near the particle surface.

[0057] In some embodiments, the relative flow rates of the additive gas or doping gas or their precursors can be adjusted over time to control the concentration of the doping agent or its precursor in at least one of the plasma 112 afterglow 146, the reaction region 128, or the extended dynamic high-temperature wall region 134, for example, to obtain a non-uniform powder composition.

[0058] An example of a mixture of precursor material 130 and an optional doping agent may include at least one of the following: The precursor material 130 includes silane (SiH4), trichlorosilane (SiCl3H), germane (GeH4), or a mixture thereof. The precursor material 130 or doping agent includes digalan (Ga2H3) or arsine (ArH3) or a mixture thereof. Between 1,000,000:1 and 1,000,000:1, for example between 1,000,000:1 and 10,000:1, between 1,000:1 and 1,000:1, between 1,000:1 and 100:1, between 1,000:1 and 100:1, between 1,000:1 and 100:1, or higher, the precursor material 130 contains silane (SiH4) and the doping agent contains diborane (B2H6), achieving p-type doping to silicon particles. Between 1,000,000:1 and 1,000,000:1, for example between 1,000,000:1 and 10,000:1, between 1,000:1 and 1,000:1, between 1,000:1 and 100:1, between 1,000:1 and 100:1, or between 1,000:1 and 100:1, the precursor material 130 contains silane (SiH4) and the doping agent contains phosphine (PH3), achieving n-type doping of silicon particles. • Between 1:0 and 1:1, for example between 1:1 and 1:2, between 1:2 and 1:4, or in a volume ratio greater than or equal to 1:0, the precursor material 130 contains silane (SiH4), and the doping agent contains ammonia (NH3) and SiN x An alloy is produced, where x ranges from 0 to 1, for example, from 0.5 to 0.9.

[0059] For example, if the nanoparticle powder is nitrogen-doped silicon or silicon alloy particles, the nanoparticle powder has a nitride layer. In some embodiments, the thickness of the nitride layer may be 0.75 nm or less, for example, 0.50 nm or less, 0.25 nm or less, 0.10 nm or less, 0.06 nm or less, or less.

[0060] In some embodiments, the nanoparticle powder contains a relatively large amount of doping agent. The doping agent X may be present in the material in Si:X ratios between 1:03 and 1:1, for example, between 1:0.4 and 1:0.9, between 1:0.5 and 1:0.8, and between 1:0.6 and 1:0.7.

[0061] For example, when Si nano-sized particles are doped with nitrogen, the nano-sized particles will have an almost stoichiometric ratio of SiN x The nitrogen content can be substantially uniform throughout the entire volume of the nanoparticles, allowing for the formation of an alloy.

[0062] In some embodiments, the nanoparticle powder has high purity. For example, the nanoparticle powder may have a purity of at least 99.95%, or at least 99.96%, 99.97%, 99.98%, 99.99%, 99.995%, and higher (e.g., at least 99.998%). For example, if the nanoparticle powder contains a silicon or silicon alloy core, the core may contain at least 99.95% silicon or silicon alloy.

[0063] In some embodiments, the precursor material 130 is added to, or instead of, the precursor material 130 is used in the injectors 1141-114 i The precursor material 130 may be mixed with an additive gas or doping agent before, simultaneously with, or after being injected into the device 100 through the injectors 1141-114 i In an embodiment in which the additive gas or doping agent is mixed with the precursor material 130 at the same time as or after it is injected into the device 100 through the same injectors 1141-114 as the precursor material 130, the additive gas or doping agent is mixed with the precursor material 130 through the same injectors 1141-114 i Through, or different injectors 1141-114 i It can be sprayed into the device 100 through it.

[0064] In some embodiments, the presence of an additive gas or doping agent in at least one of the plasma generator 120, the reaction chamber 140, and the quenching chamber 500 can create a passivation layer on nano-sized particles, resulting in particles with a core and layer structure.

[0065] Chemical vapor deposition (CVD), typically performed in an atomic layer deposition (ALD) reactor, can be used to deposit a passivation layer on nano-sized particles after their conventional production. However, in such cases, the nano-sized particles may be exposed to air during transport from the plasma apparatus where they are produced to the ALD reactor. In this disclosure, the nano-sized particles can be advantageously coated with a passivation layer in situ (within apparatus 100) before they are exposed to oxygen / air and moisture / water, thus preventing the problems faced by conventional CVD methods.

[0066] In some embodiments, the presence of a passivation layer can reduce the reactivity of the nanosized powder to oxygen / air and / or moisture / water, thereby preventing the reduction or delay of oxide layer formation. The chemical composition of the passivation layer depends on the selected additive gas. For example, using an additive gas such as oxygen results in an oxide layer, while using ammonia or nitrogen when producing silicon or silicon alloy powders results in silicon (Si3N4, or any other Si-N compound in stoichiometric or non-stoichiometric ratios). x N y A passive layer is obtained consisting of silicon alloy nitrides, or an amorphous carbon passive layer is obtained by using additive gases such as methane or acetylene.

[0067] In some embodiments, the additive gases present in the reaction chamber 140 and / or the quenching chamber 500 may also function as particle growth inhibitors. This can be useful for controlling the diameter of nano-sized particles (e.g., particle size distribution, i.e., "PSD"). For example, the concentration of a gas species such as oxygen injected into the reaction chamber 140 and / or the quenching chamber 500 allows the size of nano-sized particles to be controlled to a size range smaller than the normal diameter obtained without the use of a growth inhibitor, with the diameter being inversely proportional to the concentration of the growth inhibitor.

[0068] Changing the concentration or injection position of the additive gas alters the concentration distribution of the additive gas. For example, injection upstream of the device 100 promotes the penetration of elements present in the additive gas into the particle core, while injection downstream of the device 100 can preferentially retain elements present in the additive gas near the particle surface and / or in the passivation layer.

[0069] For example, the additive gas may be oxygen containing species such as H2O or CO2, nitrogen-containing gases such as N2 or NH3, carbon-based gases such as CH4 or C2H2, or any other gas that can be found suitable by those skilled in the art. The concentration of the additive gas injected into the reaction chamber 140 and / or the quenching chamber 500 may be between 0 and 5000 ppm, for example, less than 500 ppm.

[0070] Returning to the structural features of the device 100, Figures 5 and 6 show the injectors 1141-114 i A cross-sectional view relating to the implementation is shown. Here, the injector 1141 includes a channel 208 for injecting precursor material 130 into the apparatus 100, either alone or in combination with a carrier gas, additive gas, or doping agent. The channel 208 is defined at least partially by an annular inner surface 610. Radially outward from the annular inner surface 610 is a channel 206 for injecting sheath gas 201, defined at least partially by an annular inner surface 620. The channel 206 may be configured so that the sheath gas 201 flows within a lumen 209. The annular outer surface 630 is located radially outward from the annular inner surface 620, and the two surfaces together partition channels 203, 204 configured for circulating a cooling fluid 205. In some embodiments, the cooling fluid 205 may be a high-pressure, high-velocity cooling fluid (e.g., water) to prevent overheating of the injector 1141. The outer surface 630 and the inner surface 620 converge at a point defining the tip 202 of the injector 1141, forming an external outlet with cross-section D3. Meanwhile, channel 206 forms an intermediate outlet with cross-section D2, and channel 208 forms an internal outlet with cross-section D1, where D3 > D2 > D1. As best shown in Figure 6, the external outlet extends downstream from the internal outlet by a distance δ in the plane.

[0071] During operation, channel 206 carries sheath gas 201 into the apparatus 100, allowing the cooled tip 202 to be isolated from exposure to the precursor material 130 (and / or carrier gas, additive gas, or dope) flowing out of channel 208, thereby preventing, reducing, or minimizing condensation of the precursor material 130 on the external outlet of the injector 1141, including the tip 202. Consequently, a proper flow of sheath gas 201 allows for more sustained operation of the apparatus 100, as there is less risk of downtime that might otherwise be required to clean up the final condensation that would otherwise occur more frequently at the outlet of the injector 1141.

[0072] In conventional plasma reactors, the temperature gradient in the reaction zone is relatively steep. For example, there may be a radial gradient where the temperature is very high along the axial direction in the reaction chamber, and relatively low in a wide area toward the walls of the reaction chamber. In addition, or instead, an axial gradient may exist. Furthermore, conventional plasma reactors are subject to a significant loading effect when the precursor is injected. As the flow rate of the precursor material or sheath gas increases, the temperature in some areas of the injection zone may drop to an undesirable range, resulting in reduced processing efficiency, the production of amorphous nanoparticles, and a decrease in the quality of the resulting particles.

[0073] These inherent problems associated with conventional plasma reactors are advantageously mitigated by at least some embodiments in which a gas preheated to a desired temperature is injected into the reaction chamber 140 to form a dynamic high-temperature wall region 134 (shown in Figure 3). The presence of the dynamic high-temperature wall region 134 extends the reaction region 128 to a region downstream of the initial contact point between the plasma 112 and the precursor material 130, maximizing the exposure of the precursor material 130 to high temperatures and residence time. In other words, the injection of high-temperature gas into the dynamic high-temperature wall region 134 results in a flatter temperature distribution along the axis, and consequently, an extended residence time in the high-temperature region.

[0074] Figures 7A and 7B show details of the reaction chamber 140 of Figure 3, including an inlet 154 for injecting gas 302, preheated to a desired temperature (e.g., 600°C), into the reaction chamber 140. Those skilled in the art will readily understand that gas 302 and the aforementioned additive gas may be one and identical.

[0075] The gas 302, preheated to the desired temperature, is then placed in the reaction chamber 140 and flows through a diffusion wall 303 sandwiched between the outer wall 710 and the porous inner wall 305 of the reaction chamber 140, forming a radial preheated gas flow 304. The radial preheated gas flow 304 creates a "dynamic hot wall" region 134 that prevents reactants, such as the precursor material 130 and / or reactants present in any carrier gas, additive gas, or doping agent, and / or reactants present in the gas mixture, from reaching the inner wall 305 of the reaction chamber 140. Thus, the presence of the dynamic hot wall region 134 prevents, reduces, or minimizes heterogeneous decomposition and chemical deposition of reactants onto the inner wall 305, while providing sufficient energy to ensure the completion of the reaction through heterogeneous thermal decomposition of the remaining precursor material 130 and / or reactants onto an existing seed 306 (also referred to as "nascent particles" or "spray solid") often formed just upstream.

[0076] As shown in Figure 7B, the diffusion wall may include an additional diffusion wall outlet 333 located within the reaction chamber 140 and sandwiched between the outer wall 710 and the porous inner wall 305 of the reaction chamber 140 at the top of the reaction chamber 140. The additional diffusion wall outlet 333 delivers at least a portion of the preheated gas to the injection probe injectors 1141-114 i The nozzle is configured to inject the material into the reaction chamber 140 in a region 70 near the tip 202. Furthermore, the diffusion wall outlet 333 ensures timely mixing, dispersion, and conversion of the precursor material 130 and / or any carrier gas, additive gas, or doping agent as soon as the precursor material 130 and / or any carrier gas, additive gas, or doping agent are injected into the reactor.

[0077] During operation, the precursor material 130 is heated very rapidly by the plasma 112 and plasma afterglow 146, and a gas mixture is then generated that flows into a dynamic high-temperature wall region 134 where such a high temperature is maintained by a radial preheating gas flow 304. This advantageously allows for the decomposition and / or evaporation of the precursor material 130 at high temperatures, resulting in much higher processing capacity. For example, the inventors were able to process the silane-containing precursor material 130 at a processing capacity of at least 1 kg / hour, ranging from 1 kg / hour to 3 kg / hour, and in some embodiments even higher.

[0078] The introduction of the dynamic high-temperature wall region 134 also allows for the adjustment of dilution of the sprayed nascent particles 306 (also referred to as "nanoparticle seeds" or "nascent nanoparticle seeds") and the precursor material 130 and / or any doping agent in order to limit particle growth through aggregation of nascent particles 306. A more dilute nano-sized particle aerosol limits the collision probability of nascent particles 306 by increasing the mean free path of the particles. Furthermore, a lower concentration results in a slower diffusion rate of the gas onto the surface of the nanoparticle seeds. In addition, since lower temperatures result in lower crystallinity and higher temperatures result in higher crystallinity, the crystallinity of the formed nano-sized particles can be changed by adjusting the gas temperature in the dynamic high-temperature wall region 134.

[0079] In some embodiments, controlling the crystallinity of nano-sized particles can yield many advantageous characteristics. For example, in the production of silicon nano-sized particles, hydrogen atoms can be incorporated into the amorphous component of the nano-sized particles to form Si:H, which is used in the thin-film solar cell industry. The methods and apparatus described herein advantageously allow for the tuning of the properties of nano-sized particles for intended applications.

[0080] The radial preheating gas flow 304 can be any suitable amount. For example, in some embodiments, the gas flow can be in the range of 50 to 2000 standard liters per minute ("slpm"), e.g., between 50 and 200 slpm, 200 and 500 slpm, 500 and 1000 slpm, 1000 and 2000 slpm, and above (e.g., at least 2000 slpm).

[0081] Thermal energy can be supplied to the gas 302 by a heating element 700, such as a heat exchanger, as shown in Figure 3. The thermal energy supplied to the gas 302 may be realized through a porous wall 305, which also serves as a heating element, either additionally or instead. In such embodiments, the thermal energy can be supplied to the porous wall 305 by induction heating, resistance heating, or infrared heating. In the latter case, the infrared emitter may be positioned substantially coaxially with the porous wall 305. The infrared emitter may be positioned at the location of the gas diffusion wall 303. Thermal energy can be supplied to the gas 302 by both the infrared emitter and the porous wall 305, so that the infrared emitter also serves as a diffusion wall 303, heating the gas 302 by transmission, radiation, and indirectly heating the porous wall 305. The porous wall 305 may be made from any other porous heat-resistant material, including metal, ceramic, or composite material.

[0082] The dynamic high-temperature wall region 134 may have any length that is appropriate to allow the precursor material 130 to react as completely as possible while maintaining economic viability and efficiency. For example, in some embodiments, the dynamic high-temperature wall region 134 may have a length in the longitudinal direction of the apparatus 100 between about 100 mm and 200 mm, for example between about 200 mm and 400 mm, 400 mm and 700 mm, 700 mm and 1000 mm, and greater (for example, at least 1000 mm). Similarly, the porous wall 305 of the dynamic high-temperature wall region 134 may have a corresponding length in the longitudinal direction of the apparatus 100 between about 100 mm and 200 mm, for example between about 200 mm and 400 mm, 400 mm and 700 mm, 700 mm and 1000 mm, and greater (for example, at least 1000 mm). Similarly, the diffusion wall 303 of the dynamic high-temperature wall region 134 may have corresponding lengths in the longitudinal direction of the apparatus 100, between approximately 100 mm and 200 mm, for example between 200 mm and 400 mm, 400 mm and 700 mm, 700 mm and 1000 mm, and greater (for example, at least 1000 mm).

[0083] The diffusion wall 303 includes a plurality of openings 168n through which the gas 302 can pass. On the gas diffusion wall 303, the plurality of openings 168n can be sized and arranged in any suitable manner. For example, on the gas diffusion wall 303, the plurality of openings 168n can have at least one substantially uniform shape, size, and arrangement. For example, on the gas diffusion wall 303, the plurality of openings 168n can all have a substantially circular shape and be arranged in a substantially uniform arrangement. In some embodiments, the plurality of openings 168n can have an elongated shape in the longitudinal direction of the apparatus 100. The plurality of openings 168n can have an elongated shape in the tangential direction of the apparatus 100. The dimensions of the plurality of openings 168n can increase or decrease along the downstream direction. There may be more openings 168n located upstream of the diffusion wall 303 than there may be openings 168n located downstream of the diffusion wall 303. On the other hand, in other embodiments, there may be more openings 168n located downstream of the diffusion wall 303 than there may be more openings 168n located upstream of the diffusion wall 303. Other implementation examples are also possible.

[0084] As will be apparent to those skilled in the art, the design and operation of the “dynamic high-temperature wall” described herein differ from those of the prior art. In this disclosure, the apparatus 100 is configured such that the injected gas 302 results in a uniform and continuous radial gas flow 304, thereby preventing the deposition of powder on the surface. Other advantages obtained by this disclosure include, but are not limited to, increased reaction / conversion rates (auxiliary heating), control of nano-sized particle morphology and crystallinity (extended residence time), control of particle size (dilution effect), and avoidance of powder deposition, buildup, clogging, etc.

[0085] Several crystalline structures can be obtained by the methods and apparatus described herein. Parameters in the method can be controlled so that the nanoparticles in a given batch of powder produced in a single operation have one or more crystalline structures. Figure 4 shows explanatory diagrams of nano-sized particles 410, 420, 430, and 440, each having a different crystalline structure. For example, nanoparticle 410 is shown as a single-crystal 401 structure, nanoparticle 420 is shown as a polycrystalline 401, 402 structure, nanoparticle 430 is shown as a crystallized region 403 with an amorphous region 406 in between, and nanoparticle 440 is shown as a core-shell shape in which the core has a crystalline structure 405 and the amorphous layer 406 completely encloses the core.

[0086] Figure 8 shows a cooling chamber 500 that may be connected to the reaction chamber at the bottom of the apparatus 100, as shown in Figure 3. The cooling chamber 500 defines at least one cooling region 132 (also referred to as a “quenching region”), which has a size and configuration such that nucleation and growth from droplets can be controlled. In some embodiments, the cooling chamber 500 is in fluid communication with the reaction chamber 140 such that at least one cooling region 132 is in fluid communication with a dynamic high-temperature wall region 134.

[0087] The gaseous mixture flowing from the reaction chamber 140 is cooled in the cooling chamber 500 to a temperature at which the reaction substantially stops. The cooling chamber 500 includes an injection module 503 configured to inject a longitudinal cooling gas 502 (injected along the longitudinal direction of the cooling chamber 500), or an injection module 505 configured to inject a radial cooling gas 504. In some embodiments, the cooling chamber 500 may include both injection modules 503 and 505 for injecting the longitudinal cooling gas 502 and the radial cooling gas 504, respectively. In other embodiments, the cooling chamber 500 may include multiple injection modules for injecting a corresponding group of cooling gases (not shown).

[0088] The composition of either or both of the longitudinal cooling gas 502 and the radial cooling gas 504 may be selected to carry the growth inhibitors described above. Thus, the longitudinal cooling gas 502 and the radial cooling gas 504 may be, for example, one and identical.

[0089] In some embodiments, the chemical composition of the cooling gas may be identical to that of one or more other gases injected into the apparatus. In some embodiments, the cooling gas is advantageously composed of a recirculated gas, where the gas recovered from the apparatus 100 at the lower outlet of the apparatus 100 is recirculated, cooled to a desired temperature, and reinjected into the apparatus 100 as one or both of the cooling gases described herein. For example, when the gases listed in Tables 2A and 2B, i.e., 30 argon + 95 argon + 15 H2 + 50 or 150 argon, and 250 N2 are injected into the apparatus, a recirculated cooling gas having the following chemical composition is obtained: 40% argon, 3% H2, and 57% N2, or 51% argon, 3% H2, and 46% N2.

[0090] In some embodiments, further diluting the gas by injecting one or more cooling gases into the cooling chamber 500 may be useful in preventing aggregation of high-temperature nano-sized particles, and as a result, may also contribute to controlling the size of the nano-sized particles.

[0091] The temperature and / or flow rate of either or both of the longitudinal cooling gas 502 and radial cooling gas 504 introduced into the cooling chamber 500 also affects the condensation rate of the reactant gas mixture, allowing control of the size of the nanosized powder particles and the PSD, and preventing particles from adhering to the inner wall 506 of the apparatus 100. Specifically, lower temperature quenching gases increase the rate at which the reactant gas mixture condenses, thus reducing the PSD. Conversely, higher temperature quenching gases generally increase the PSD. Similarly, the time the core reacts with the additive gas increases at higher temperatures, which can result in a thicker passivation layer. On the other hand, generally, lower temperatures can result in a thinner passivation layer. Therefore, the temperature and / or flow rate of either or both of the longitudinal cooling gas 502 and radial cooling gas 504 introduced into the cooling chamber 500 can be controlled not only to adjust the PSD but also to produce a passivation layer of the desired thickness. The temperature range inevitably depends on the chemical composition of the reactant gas mixture. For example, when producing nano-sized particles of silicon or silicon alloy, either or both of the longitudinal cooling gas 502 and the radial cooling gas 504 may be injected into the cooling chamber 500 until the reaction reaches a temperature at which it substantially stops, such as 420°C or below, which is selected from a temperature in the range of 420 to 600°C or from a temperature in the range of 300 to 420°C.

[0092] Accordingly, in some embodiments, the growth and crystallinity properties of the particles obtained in this disclosure can be controlled by adjusting the flow rate, chemical composition, and temperature of the gas injected into the apparatus 100, for example, the gas mixed with the precursor material 130, the gas injected into the reaction chamber 140, and the gas injected into the cooling chamber 500.

[0093] In view of this disclosure, several modifications will be apparent to those skilled in the art. For example, in some embodiments, a first additive gas can be introduced together with the precursor material 130, and at the same time, optionally, a second additive gas having the same or different properties as the first additive gas can be introduced into the dynamic high-temperature wall region 134 in the form of a radial preheating gas flow 304, and at the same time, optionally, a third additive gas having the same or different properties as the first and second additive gases can be introduced into the cooling section 132 (also referred to herein as the “rapid cooling section”) in the form of either or both of a longitudinal cooling gas 502 and a radial cooling gas 504. The flexibility with respect to the injection point, flow rate, and temperature of such additive gases allows those skilled in the art to control and adjust the overall effect on particle growth and properties.

[0094] While not bound by any particular theory, the reaction between the particle core and the added gas is thought to occur when the core comes into contact with the added gas at a temperature within the temperature range that allows the reaction. Depending on the gas species / temperature, diffusion through the particle radius may also be important. This temperature range depends on the properties of both the core and the added gas. Furthermore, the lower end of this temperature range must be lower than the temperature at which the reactant gas mixture condenses to form a core; otherwise, a core will not form at the temperature at which the reaction should occur. For example, if the particles are made from silicon or a silicon alloy and the added gas is N2, the reaction temperature must be below approximately 3265°C (the evaporation point of silicon) while simultaneously being above the lowest temperature at which Si and N2 will react within the available residence time.

[0095] Furthermore, although not bound by any particular theory, the thickness of the passivation layer can depend on many factors, but is ultimately thought to be determined by the degree of reaction of the added gas (passivation layer gas precursor) on the surface of the particle core, and the degree of diffusion of the added gas onto the surface of the particle core, and more broadly onto the particle. Generally, a larger reaction scale results in a thicker passivation layer, and a smaller reaction scale results in a thinner passivation layer. Instead, when manufacturing silicon-based nanoparticles, silicon itself can diffuse into the passivation layer to the outer surface, and growth proceeds. Tests have shown that the thickness of the passivation layer can be increased by increasing the time the core resides in a section of the apparatus where a passivation layer can be formed, for example, a part of the reaction zone 134 or the quenching zone 132, for example, a part of the quenching zone 132 where the temperature is low enough for vapor condensation to occur, but high enough for the particle to react with the passivation layer gas precursor. This can be increased by increasing the volume of the portion of the rapid cooling section 132, increasing the concentration of the passivation layer gas precursor in the rapid cooling section 132, increasing the temperature of the passivation layer gas precursor, and extending the residence time by auxiliary heating, such as described in US9,516,734, which is incorporated herein by reference.

[0096] In some embodiments where it is desirable to preserve the electron and ion diffusion properties in the nanoparticle layer, controlling the thickness of the passivation layer can also provide several advantages. For example, in such applications, the thickness of the passivation layer can be up to about 5 nm, or up to about 3 nanometers. Therefore, one or more of the above factors can be adjusted by considering the composition of the nano-sized particles and the passivation gas precursor to produce such a passivation layer.

[0097] Figure 9 shows an assembly 900 for carrying out the method described herein on an industrial scale for producing nanosized particles. The assembly 900 includes a device 100 and a gas distributor 30 that is in fluid communication with the device 100 and injects gas into the reaction chamber 140 and cooling chamber 500 of the device 100. As shown, the injected gases include gas 302 that is preheated to a desired temperature by element 700 and injected into the reaction chamber 140, and longitudinal cooling gas 502 and radial cooling gas 504 that are injected at different locations in the cooling chamber 500. As previously stated, gases 302, 502, and 504 may be identical or different depending on the various applications and the properties of the desired nanosized particles.

[0098] Once formed, the nano-sized particles, according to their PSD, are separated from the gas flow in a downstream cyclone (not shown) and sent to a powder recovery point 178 and / or into a recovery filter 910 which is in fluid communication with the apparatus 100, and may also be sent to a powder recovery point 188. The nano-sized particles may be transported to the downstream cyclone and / or recovery filter 910 by gravity, or by gas or suction. The nano-sized particles may be transported to the downstream cyclone and / or recovery filter 910 in a direction other than perpendicular to the apparatus 100.

[0099] Optionally, at least a portion of the exhaust gas obtained after separating nano-sized particles from the gas flow may be recirculated and sent back to the method using at least one compressor (not shown). Optionally, at least a portion of the exhaust gas obtained after separating nano-sized particles from the gas flow may be treated through a decontamination system 920 that generates exhaust gas. The assembly 900 is shown in Figure 9 to include three gas pump units (GPUs) 2, 8, and 33 in specific locations, but more than three or fewer GPUs may be used in different applications and / or in different locations.

[0100] In this assembly 900, the gaseous precursor is introduced into the high-temperature region of the apparatus 100, where the high-temperature region is generated by a thermal plasma, and the gaseous precursor begins to decompose into its atomic components. Multiple injectors allow for the injection of gaseous raw materials downstream of the plasma outlet, ensuring a uniform reaction of the gas. The use of multiple injectors allows for the introduction of more raw materials. Downstream of the torch is a dynamic high-temperature wall region, a continuously renewed virtual surface formed by a radial flow of high-temperature gas, which keeps the reactants away from the solid reactor wall, preventing non-uniform decomposition and chemical deposition. The dynamic high-temperature wall also supplies additional energy to the system, causing the raw materials to decompose completely at an unprecedented rate, resulting in the production of economically viable nanometer powders.

[0101] As a non-limiting variation, the fluid precursor material may be directly injected into the plasma gas of one or more DC plasma torches. This can also be used in conjunction with multiple injection probes downstream or upstream of the plasma heat source.

[0102] Battery applications The nanoparticle powders described herein, in particular when these nanoparticle powders are silicon or silicon alloy-based, can be used in the manufacture of rechargeable electrochemical batteries having advantageous properties. Typically, a rechargeable electrochemical battery is a lithium secondary battery consisting of a positive electrode, a negative electrode, and an electrolyte layer for a lithium secondary battery.

[0103] Typically, the positive electrode consists of aluminum foil containing, for example, expanded metal (e.g., expanded metal foil commercially available from Exmet, Inc. in the United States), and optionally a positive electrode current collector having a carbon-based protective film (e.g., a current collector commercially available from Exopack® Advanced Coating, Inc. in the United States), as well as a binder and generally conductive additives, CA x M(XO4) yThe battery has a layer of positive electrode active material containing [a specific material]. As the binder contained in the layer of positive electrode active material, known resin materials commonly used as binders for positive electrode active material layers in this type of lithium secondary battery can be used. Examples include polyvinylidene fluoride (PVdF), polytetrafluoroethylene, polyvinyl chloride, polyvinylpyrrolidone, styrene-butadiene rubber (SBR), polymethyl methacrylate (PMMA), polyethylene oxide (PEO), and mixtures thereof. Among these, polyvinylidene fluoride and its derivatives are commonly used in lithium-ion batteries, and PEO and its derivatives are commonly used in lithium metal polymer batteries. As the conductive additive contained in the layer of positive electrode active material, known conductive agents commonly used in this type of lithium secondary battery, such as spherical (granular), flake, or fibrous forms, can be used, without any limitations. Examples include carbon black, graphite, carbon fiber, nanotubes, graphene, vapor-grown conductive fiber (VGCF), and mixtures thereof.

[0104] Specifically, the negative electrode may include a collector coated with a material obtained by mixing a negative electrode active material and a binder. The negative electrode active material comprises silicon or silicon alloy nano-sized particles as described herein, either alone or in combination with any other active material. Examples include carbon materials such as natural graphite, artificial graphite, ungraphitized carbon, and graphitized carbon; metallic materials such as metallic lithium, lithium alloys, and tin compounds; lithium transition metal nitrides, crystalline metal oxides, amorphous metal oxides; titanium oxide such as TiO2 or carbon-coated TiO2; and Li4Ti5O 12 or carbon-coated Li4Ti5O 12 Examples include lithium titanium oxide and conductive polymers. The binder can be a known organic or inorganic binder, such as polyvinylidene fluoride (PVdF), which is shown as a binder that can be used for the positive electrode. Examples of negative electrode collectors include copper and nickel in the form of mesh, punched metal, foamed metal, or foil processed into sheets.

[0105] The electrolyte layer is held by the positive electrode layer and the negative electrode layer and contains an electrolyte solution, a polymer containing an electrolyte salt, a polymer gel electrolyte, or a plasticized or non-plasticized polymer electrolyte. When an electrolyte solution or polymer gel electrolyte is used, a separator is usually used in combination. The separator electrically insulates the positive electrode and the negative electrode and holds the electrolyte solution, etc.

[0106] The electrolyte can be any electrolyte commonly used in lithium secondary batteries, including common examples of organic electrolytes, polymer electrolytes, or ionic liquids, and mixtures thereof. Examples of electrolyte salts include LiPF6, LiBF4, LiClO4, LiAsF6, LiCl, LiBr, LiCF3SO3, LiN(CF3SO2)2, LiC(CF3SO2)3, LiN(FSO2)2, LiC(FSO2)3, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, and Li2B 12 F x H 12-x (10≦x≦12), LiI, LiAlCl4, NaClO4, NaBF4, and inorganic lithium salts such as NaI, especially LiPF6, LiBF4, and LiClO4, and LiN(SO2C x F 2x+1 )(SO2C y F 2y+1 Organolithium salts represented as (where x and y independently represent integers from 0 or 1 to 4, and x + y is from 2 to 8) are examples. Specific examples of organolithium salts include LiN(SO2F)2, LiN(SO2F3)(SO2C2F5), LiN(SO2CF3)(SO2C3F7), LiN(SO2CF3)(SO2C4F9), LiN(SO2C2F5)2, LiN(SO2C2F5)(SO2C3F7), and LiN(SO2C2F5)(SO2C4F9). Among these, LiPF6, LiBF4, LiN(CF3SO2)2, LiN(SO2F)2, and LiN(SO2C2F5)2 are commonly used as electrolytes due to their superior electrical properties. Electrolyte salts can be used individually or in combinations of two or more types.

[0107] The organic solvent used to dissolve the electrolyte salt is not particularly limited and may be any organic solvent commonly used in non-aqueous electrolytes of lithium secondary batteries, examples of which include carbonate compounds, lactone compounds, ether compounds, sulfolane compounds, dioxolane compounds, ketone compounds, nitrile compounds, and halogenated hydrocarbon compounds. Specific examples include carbonate compounds such as dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, fluoroethylene carbonate, propylene carbonate, ethylene glycol dimethyl carbonate, propylene glycol dimethyl carbonate, ethylene glycol diethyl carbonate, and vinylene carbonate; lactone compounds such as δ-butyrolactone; ether compounds such as dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,4-dioxane; sulfolane compounds such as sulfolane and 3-methylsulfolane; dioxane compounds such as 1,3-dioxane; ketone compounds such as 4-methyl-2-pentanone; nitrile compounds such as acetonitrile, propionitrile, valeronitrile, and benzonitrile; halogenated hydrocarbon compounds such as 1,2-dichloroethane; and ionic liquids such as methyl formate, dimethylformamide, diethylformamide, dimethyl sulfoxide, imidazolium salts, and quaternary ammonium salts. Organic solvents can be mixtures of these solvents. Among organic solvents, at least one non-aqueous solvent, usually selected from the group consisting of carbonate compounds, is typically included due to its excellent solubility, dielectric constant, and viscosity of the electrolyte. Examples of polymer compounds used in polymer electrolytes or polymer gel electrolytes include polymers, copolymers, and their crosslinking products such as ethers, esters, siloxanes, acrylonitriles, vinylidene fluoride, hexafluoropropylene, acrylates, methacrylates, styrenes, vinyl acetates, vinyl chlorides, and oxetanes. Polymers can be used individually or in combinations of two or more types. The polymer structure is not particularly limited, and polymers may have ether structures such as polyethylene oxide.

[0108] In lithium secondary batteries, the electrolyte is housed in a cell container for liquid-type cells, the precursor solution containing the polymer dissolved in the electrolyte is housed in a cell container for gel-type cells, or the pre-crosslinked polymer containing the electrolyte salt dissolved therein is housed in a cell container for solid-electrolyte-type cells.

[0109] The separator can be any separator commonly used in lithium secondary batteries, such as porous resins formed from polyethylene, polypropylene, polyolefin, polytetrafluoroethylene, etc., ceramics, and nonwoven fabrics. The separator can also be a dry polymer or plasticizer having an ether structure, such as polyethylene oxide for lithium metal polymer batteries.

[0110] The battery being tested may be a "button" type battery assembled and sealed in a glove box. For example, such a battery may have a cathode material (e.g., 4.5 mg / cm³). 2 The test battery may include a carbonized aluminum sheet supporting a coating containing a certain amount of C-LiFePO4, a film containing an anode material (including silicon or silicon alloy nano-sized particles) as described herein, and a 25 μm thick separator (supplied by Celgard) impregnated with a 1 M LiPF6 solution in an EC / DEC(3 / 7) mixture. As those skilled in the art will be able to recall other modifications of the test battery in light of the teachings herein, for the sake of brevity, further descriptions thereof are not included herein.

[0111] Batteries can be tested in an intensiostatic cycle according to procedures known in this art. For example, at 25°C and a rate of C / 12, a battery can be tested with oxidation from a residual potential of 4V or less, followed by reduction between 4V and 2.2V, and then a charge / discharge cycle in the range of 2.2V to 4V. Alternatively, or in addition, it can be tested at a temperature of 45°C and a rate of C / 8, and / or at a temperature of 60°C and a rate of C / 8.

[0112] definition Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention relates. Unless otherwise stated or required by the context, the following terms used herein have the definitions set forth below.

[0113] As used herein, the term "powder particles" as a whole refers to particulate matter including, but not limited to, micron-sized particles and nano-sized particles.

[0114] As used herein, the term "plasma" generally refers to a gas in a partially ionized state at high temperatures.

[0115] As used herein, the term "plasma torch" refers collectively to a device capable of transforming a gas into a plasma.

[0116] As used herein, the term “inductively coupled plasma torch” refers collectively to a type of plasma torch that uses electric current as an energy source to produce electromagnetic induction of energy into a plasma.

[0117] As used herein, the term “injection probe” as a whole refers to an elongated conduit for introducing or supplying a feed material. In some embodiments, such an injection probe may be cooled using a cooling fluid. [Examples]

[0118] The following examples illustrate some typical forms of producing and carrying out the specific compositions described herein. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the compositions and methods described herein.

[0119] (Example 1) In this embodiment, standard operating conditions for obtaining silicon nanoparticles by the decomposition of silane are described.

[0120] Standard operating conditions include plasma torch operating conditions, silane injection method, high-temperature gas flow rate and temperature, distribution of quenched gas flow in the reactor, and operating pressure in the system. Table 1 shows the operating conditions used to acquire experimental data, namely a plasma output of 77-80 kW, a plasma center gas flow of 30 liters per minute (lpm) of argon, a plasma sheath gas flow of 95 lpm of argon and 15 lpm of H2, with silane injected under a PN-50 plasma torch using three SG1270 probes (120° apart with a downward injection angle of 15-20°). The gases introduced into the reactor consisted of two types: 250 lpm of unused N2 in the fishtail module, and 8500 lpm of recirculated (Ar+H2+N2) mixture gas at various locations in the reactor, of which 1500 lpm was heated to 500°C before injection to the top of the reaction zone. The reactor pressure was maintained at 14.5 psia.

[0121] [Table 1]

[0122] (Example 2) In this embodiment, alternative operating conditions for obtaining silicon nanoparticles through the decomposition of silane, and the nanoparticles obtained thereby, are described.

[0123] Table 2 describes several test runs conducted using alternative operating conditions and the results of the analysis of the resulting powders. The alternative operating conditions were one or more of the total silane injection velocity, diluted argon flow rate, quenching gas flowing through the top of the fishtail module, and passivation oxygen flow rate.

[0124] Powder was recovered from the bottom of the filter (FB) and from the walls and bottom of the reactor (RWB). The production rate was evaluated based on the powder recovered from the bottom of the filter, and the yield was calculated based on the comparison of the production rate and the supply rate (assuming complete conversion from SiH4 to Si).

[0125] Nanoparticle powders were analyzed using BET, Malvern's PSD, XRD, FE-SEM, LECO's O%, C%, N%, H%, and ICP-MS. The average particle size was evaluated based on the BET specific surface area, and the crystallite size was calculated using Sherrer's formula.

[0126] [Table 2]

[0127] The results of these tests demonstrate that nanosized silicon powders with average particle sizes ranging from 52 to 212 nm can be produced. The production rate varied from approximately 1 kg / m² to 3.65 kg / m², and the recovery yield varied from 41.6% to 97.2% by mass. Oxygen content and other additives or impurities can be controlled by operating conditions. The majority of the produced powders are spherical or nearly spherical, with crystallite sizes ranging from 24 to 42 nm.

[0128] (Example 3) In this embodiment, silicon nanoparticles were obtained by decomposing silane using embodiments of the apparatus and methods described herein.

[0129] Table 3 below lists three types of Si powder with different particle sizes. Powders with average particle sizes of 212, 113, and 52 nm were produced at silane injection concentrations of 37.5%, 25%, and 16.67%, respectively.

[0130] [Table 3]

[0131] (Example 4) In this embodiment, silicon nanoparticles were obtained by decomposing silane using embodiments of the apparatus and methods described herein, and were compared with silicon nanoparticles obtained using prior art apparatus and methods that use microsilicon powder as a precursor (for comparison).

[0132] Table 4 shows a comparison between nano-Si powder produced using micro-silicon powder as a precursor and nano-Si powder produced using silane as a precursor.

[0133] [Table 4]

[0134] The comparative powder and the powder according to the embodiments of this disclosure appear to be generally similar to each other. However, significant differences are observed in particle size distribution and purity. The comparative powder produced from microsilicon has a broad size distribution, including microsized particles in the nanopowder product. These microsized particles originate from incomplete evaporation during the plasma process and are also carried to the powder collector as contaminants. These microsized particles are not present in the nanoSi powder produced from the silane precursor. Ultimately, the purity of the product powder was directly related to the purity of the precursor. Since silane is much purer than the microsized silicon powder, the nanoSi produced from silane was also pure.

[0135] (Example 5) Figures 10 to 13 show the simulation results.

[0136] Figure 10 shows the favorable effect of the temperature (K) of the dynamic high-temperature wall gas on the silane conversion rate (%). Figure 11 shows a graph of the effect of the injector sheath gas flow on the silane conversion rate (%). Figure 12 shows the favorable relationship between the injector sheath gap (mm) and the silane conversion rate (%). Figure 13 shows the effect of two types of injectors on the silane conversion rate (%).

[0137] (Example 6) Different tests were conducted to investigate the effects of various gas volumes within the system. Table 1 shows standard operating parameters, and Table 2 shows alternative operating parameters for the tests, along with some relevant data measured for the powder. The parameters of interest were the silane supply rate, the silane dilution gas volume, and the quenching volume. The silane supply rate simply corresponds to the volumetric flow rate of silane injected into the apparatus.

[0138] The diluent gas is introduced into the apparatus through a silane injection probe. As shown in Figure 5, this is represented as a flow 201 in the gap space 209. The silane and diluent gases are injected in a three-probe configuration. The probe positions are shown in Figure 1 by element 130, and in the three-probe configuration, the probes are distributed with three rotational symmetry (i.e., 120°) around the reactor axis. The cooling gas (quenched gas) is injected immediately after the high-temperature section, which is two separate sections where FT1 is upstream of FT2. Both sections are included in region 503 of the configuration shown in Figure 8. All other gas flows are shown in Table 1.

[0139] Figure 14A shows the XRD peak shape of the first powder (BET=12.14m). 2 / g)(dP=212nm)(O%=0.20)(C%=0.066)(N%=1.200)(H%=0.020). Figure 14B shows the SEM image of the powder in Figure 14A. The powder was synthesized using the conditions shown in Test #1 of Table 2. The conditions correspond to low silane supply rate, low dilution, and low quenching conditions. The crystallite size obtained from the XRD profile was 42 nm, and the diameter obtained from BET was 212 nm.

[0140] Figure 15A shows the XRD peak shape of the second powder (BET=23.25m). 2 / g)(dP=111nm)(O%=1.20)(C%=0.030)(N%=0.550)(H%=0.020). Figure 15B shows the SEM image of the powder in Figure 15A. The powder was synthesized using the conditions shown in Test #3 of Table 2. The conditions correspond to high silane supply rate, high dilution, and high quenching conditions. The crystallite size obtained from the XRD profile was 35.9 nm, and the diameter obtained from BET was 109 nm.

[0141] Figure 16A shows the XRD peak shape of the third powder (BET=49.4m). 2 / g)(dP=52nm)(O%=2.10)(C%=0.029)(N%=0.360)(H%=0.038). Figure 16B shows the SEM image of the powder in Figure 16A. The powder was synthesized using the conditions shown in Test #5 of Table 2. The conditions correspond to low silane supply rate, high dilution, and high quenching conditions. The crystallite size obtained from the XRD profile was 24.5 nm, and the diameter obtained from BET was 52 nm.

[0142] Higher quenching volume, higher dilution volume, and lower feed rates all appear to contribute to the generation of smaller particle sizes. This may be due to the inhibition of nucleation and growth dynamics, as well as the suppression of aggregation through dilution of agglomerating species.

[0143] Figures 17A, 17B, and 17C show SEM images of silicon powder produced using silane as a precursor material, respectively. These figures compare the particle sizes synthesized using the conditions of tests #1, 3, and 5 in Table 2, with all other parameters according to Table 1.

[0144] (Example 7) Figures 18 to 23 show a comparison between powders synthesized from solid raw materials according to prior art methods and apparatus (comparative powders) and powders synthesized using the apparatus and methods described herein.

[0145] The powders relating to this disclosure were synthesized using the conditions of Test #6 in Table 2, with all other parameters according to Table 1. A comparative powder was synthesized in an induction plasma system according to the method described in US8,013,269. The silicon powder supply rate was 4.5 g / min, and the plasma output was 45 kW. The gases used in the torch were 90 slpm Ar and 10 slpm H2.

[0146] Figures 18A and 18B show prior art corresponding to Figures 21A and 21B.

[0147] Figures 18A and 18B show comparative silicon powders (BET = 32.38 m) produced using a micron-sized silicon solid precursor material by the prior art plasma torch method. 2 / g)(d p Figures 21A and 21B show SEM images of silicon powder (BET=31.04m) produced using silane as a precursor material. 2 / g)(d p The SEM images for 83nm (0%=1.80) and 0%=0.75 are shown.

[0148] Figure 21A shows the absence of large particles. Conversely, large particles resulting from the incomplete evaporation of the solid raw material used in the prior art method are observed in Figure 18A. A trained observer will also notice that the size distribution presented in Figure 18B is wider than that in Figure 21B, meaning the particle size distribution is wider in the comparison powder.

[0149] Figure 20 shows a graph of PSD (particle size in μm units) at the number density (%) of the comparative powders in Figures 18A and 18B. Figure 23 shows a graph of PSD (particle size in μm units) at the number density (%) of the powders in Figures 21A and 22B. As expected, Figure 20 shows a wider distribution than Figure 23, with the distribution centered on larger particles (>120 nm) (D 50Figure 19 shows graphs of PSD (particle size in μm units) at volume density (%) for the comparative powders in Figures 18A and 18B. Figure 22 shows graphs of PSD (particle size in μm units) at volume density (%) for the powders in Figures 21A and 21B.

[0150] The volume distribution of the comparative powder exhibits both primary and secondary distributions. The latter is due to the raw materials that did not evaporate and is consistent with the previously mentioned observations. This secondary distribution is not observed in the number distribution, revealing that large particles can have an unbalanced impact in applications such as energy storage, where mass and volume are included in energy density calculations.

[0151] (Example 8) Figures 24 to 26 show a comparison of the charge capacity behavior of rechargeable lithium batteries containing the nanoparticles of this disclosure or comparative nanoparticles obtained by prior art methods using solid raw material materials as the anode material.

[0152] Figure 24 shows a relative comparison of the charge capacity behavior of a rechargeable lithium battery containing Si nanoparticle powder with a narrow particle size distribution (PSD) as the anode material, compared to a wide PSD. A wide PSD means that the diameter of most of the sample exceeds the critical cutoff diameter of 150 nm. As previously mentioned, these larger particles are gradually disconnected from the anode as swelling and decay occur, which is reflected in the decreasing charge capacity.

[0153] Figure 25 shows the charge capacity behavior of a rechargeable lithium battery containing a Si nanoparticle / graphite composite anode, compared to a Si microparticle / graphite composite anode of the same composition. As particles larger than the 150 nm cutoff diameter decay and are disconnected from the anode, the capacity gradually tends to approach that of a cell with a graphite anode. More capacity remains as the particles become nano-sized. Those familiar with this field will recognize that if all silicon is disconnected, the trend for micron-sized particles should be lower than that of a pure graphite anode, but this effect has been omitted for simplification.

[0154] Figure 26 shows SiN as the anode material. x This shows a relative comparison of the charge capacity behavior of a rechargeable lithium battery containing composite nanoparticle powder with that of a Si micron-sized powder with a wide PSD. Initially, the SiN was uniform. x The composite nanoparticles are converted into a two-phase material through lithiation, in which nitrogen-rich regions and pure Si regions are separated. This morphological change allows for silicon expansion while preserving particle integrity and therefore the connection to the anode. Figure 26 shows that due to the low degree of lithiation of the composite, SiN x This shows that the initial capacity of the composite is lower than that of pure silicon particles. However, the charge capacity is conserved through charge-discharge cycles. On the other hand, the micro-sized particles decay and no longer contribute to the battery capacity. Therefore, SiN x The curve for the composite shows a constant value, while the curve for the microsized Si particles shows a decaying value.

[0155] Figure 27 provides a graphical explanation of the results reported in one or more tables disclosed herein, illustrating the effect of silane concentration on the average particle size of the resulting nanoparticles.

[0156] The technologies disclosed herein enable the mass production of novel cell components that have been shown to improve cell performance in both storage and charge / discharge properties. This allows for advantageous market deployment and provides a competitive advantage to leading companies in the "cell components" sector of the industry's value chain.

[0157] This technology provides a solution for mass production at a reasonable cost while simultaneously improving performance. This aligns with the recent advancements in both cost and performance of lithium-ion batteries, which have been progressing in opposite directions.

[0158] All references cited throughout this specification are incorporated herein by reference for all purposes.

[0159] Throughout this disclosure, titles and subtitles may be used for the convenience of the reader, but it should be noted that these are not in any way limited to the scope of the invention. Furthermore, certain theories may be presented and disclosed herein, but whether correct or incorrect, they are not in any way limited to the scope of the invention, as long as the invention is practiced in accordance with this disclosure without being bound by any particular theory or mechanism of action.

[0160] All references cited throughout this specification are incorporated herein by reference for all purposes.

[0161] Throughout the specification, references to "certain embodiments," etc., mean that certain elements (e.g., features, structures, and / or characteristics) described in relation to the invention are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the features relating to the described invention can be combined in any suitable way into various embodiments.

[0162] Those skilled in the art will understand throughout this specification that the term “one (a)” used before any term includes embodiments that include one or more of the items to which the term is attached. Those skilled in the art will also understand throughout this specification that the terms “comprising,” which are synonymous with “including,” “containing,” or “characterized by,” are comprehensive or open-ended terms and do not exclude additional elements or steps of methods not described herein.

[0163] Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this invention relates. In case of any conflict, this document shall prevail, including definitions.

[0164] As used in this disclosure, the terms “around,” “about,” or “approximately” mean, as a whole, within the generally accepted tolerance in the art. Accordingly, any numerical quantities given herein include such tolerances as a whole, so that, unless expressly specified, the terms “around,” “about,” or “approximately” can be inferred.

[0165] While various embodiments of this disclosure have been described and explained, it will be apparent to those skilled in the art that numerous modifications and variations are possible based on this description. The scope of the invention is more specifically defined in the appended claims. [Explanation of Symbols]

[0166] 20 Plasma central gas 30 Gas distributor 40 Plasma sheath gas 100 devices 110 Inner tube plasma sealing tube 112 Plasma 1141~114i Forerunner injector 120 Plasma Generator 126 Induction Coil 128 Reaction range 130 Precursor materials 134 Dynamic high-temperature wall region 140 Reaction Chamber 146 Plasma Afterglow 181 Outer cylinder torch body 185 head 201 Sea Gas 205 Cooling fluid 302 Gas 303 Diffusion Wall 305 Porous inner wall 306 Seed 304 Preheating gas flow 333 Diffusion wall outlet 500 Cooling Chamber 502 Longitudinal cooling gas 503 Injection Module 504 Radial cooling gas 505 Injection Module 600 Powder Recovery Machine 710 Exterior Wall 900 assembly 910 Recovery Filter

Claims

1. - supplying a fluid precursor material along a supply path to a reaction zone, said reaction zone being within a reaction chamber, said reaction chamber having a longitudinal axis; - generating a plasma in the reaction zone, the plasma contacting the precursor material to produce a reactant gas mixture; - injecting gas to generate a radial gas flow in the reaction chamber along at least a portion of the longitudinal axis; and - cooling said reactant gas mixture in a cooling zone to promote nucleation and produce nanoparticles. A method for producing nanoparticles comprising the steps of:

2. The method of claim 1 , wherein a delivery mechanism including an elongated structure delivers the precursor material in a fluid form to the reaction zone, the elongated structure defining a channel for receiving the precursor material.

3. The method of claim 2 , wherein the feeding mechanism comprises a plurality of elongated structures arranged in series along the longitudinal axis.

4. The method of claim 2 , wherein the feeding mechanism includes a plurality of elongated structures disposed about the longitudinal axis.

5. The method of claim 2 , wherein the plasma is emitted into the reaction zone by a nozzle having an outlet.

6. The method of claim 2 , wherein the plasma is generated from a gas comprising argon, helium, or a combination thereof.

7. The method of claim 6 , wherein the gas further comprises hydrogen, oxygen, nitrogen, or any combination thereof.

8. The method of claim 2 , wherein the delivery mechanism further delivers a carrier gas into the reaction zone.

9. 9. The method of claim 8, wherein the carrier gas is mixed with the precursor material before, simultaneously with, or after the precursor material is injected into the reaction zone.

10. 10. The method of claim 8, wherein the carrier gas comprises argon, helium, or a combination thereof.

11. The method of claim 10 , wherein the carrier gas further comprises hydrogen, oxygen, nitrogen, or any combination thereof.

12. The method of claim 8 , wherein the supply mechanism is configured to adjust the relative flow rates of the carrier gases to control the concentration of the precursor material in the reaction zone.

13. The method of claim 2 , wherein the reactant gas mixture comprises the precursor material in a dissociated or chemically transformed form.

14. The method of claim 2 , wherein the supply mechanism further supplies an additive gas or dopant into the reaction zone, the cooling zone, or both.

15. 3. The method of claim 2, further comprising: generating a plasma jet in the reaction zone, the plasma jet impacting the precursor material at a confluence of the plasma jet streamlines and the feed passage to produce the reactant gas mixture, the plasma jet streamlines being at an angle to the feed passage.

16. 16. The method of claim 15, wherein the angle of the plasma jet streamlines relative to the feed channel angle is between 10° and 80°.

17. 10. The method of claim 1, wherein the temperature of the gas generating the radial gas flow is sufficient to expand the reaction zone to a downstream region of the reaction zone and produce additional amounts of the reactant gas mixture with precursor material present downstream of the reaction zone.

18. The method of claim 1 , wherein the gas generating the radial gas flow comprises oxygen-containing molecules, nitrogen-containing molecules, or carbon-containing molecules.

19. The gases generating the radial gas flow are Ar, N ２ 10. The method of claim 1 , further comprising:

20. The method of claim 1 , wherein the radial gas flow prevents reactive species in the gas mixture from reaching an interior wall of the reaction chamber.

21. The method of claim 1 , wherein the step of injecting gas and creating the radial gas flow comprises injecting preheated gas.

22. The method of claim 1 , wherein the precursor material comprises silane, trichlorosilane, or silicon tetrachloride.

23. a reaction chamber having a longitudinal axis and a reaction zone configured to receive a precursor material supplied in fluid form to the reaction zone along a supply channel; a plasma generating device configured to generate a plasma in the reaction zone, the plasma being in contact with the precursor material to produce a reactant gas mixture; an injector configured to inject gas to generate a radial gas flow in the reaction chamber along at least a portion of the longitudinal axis; and a cooling zone configured to cool the reactant gas mixture to promote nucleation and produce nanoparticles; A nanoparticle manufacturing apparatus comprising:

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