Improved microgranulation process and product particles produced thereby

Abstract

A simple, material-efficient microparticulation process is disclosed for aggregating precursor particles into larger product particles having improved properties and, in some cases, novel structures. The product particles can be used in applications requiring uniform, smooth, spherical, or rounded particles, such as electrode materials for lithium batteries and other applications.

Description

TECHNICAL FIELD

[0001] The present invention relates to an improved microparticulation process for the aggregation of precursor particles into larger product particles having improved properties and, in some cases, novel structures. The product particles can be used as electrode materials in lithium batteries, as well as for other applications.

[0002] BACKGROUND

[0003] Many applications require powders composed of dense particles in the micrometer size range (e.g., 1-100 pm) and with a narrow particle size distribution (e.g., active powders for battery electrodes, fertilizers, pharmaceuticals, toners, pigments, fillers, catalysts, etc.). In some of these applications, spherical or rounded particles are desired. However, it is difficult to manufacture micrometer size range particles that are uniform in shape and size.

[0004] For example, it can be desirable for particles used in the manufacture of electrodes for high energy density rechargeable batteries, such as Li-ion batteries, to have a spherical shape and to have a uniform size. Also, given the large demand for these batteries, it is important to be able to supply such materials in large quantities and economically. Currently, cathode particles for Li-ion batteries (e.g., lithium nickel manganese cobalt oxide or NMC) are often prepared by a co-precipitation process in a continuous flow tank reactor. This results in a wide particle size distribution because the residence time of the particles in the reactor can vary. In addition, careful process control and various chemical additives (e.g., chelating agents) are required to maintain uniform precipitation rates of the different metal salts and to achieve uniform spherical particle shape. Further, after the co-precipitation process, the particles need to be separated from their mother liquor by filtration and washed, dried, and blended with a lithium source, followed by sintering, which creates additional processing steps and energy consumption, chemical waste, and wastewater. Anode particles for Li-ion batteries are typically carbonaceous particles, such as graphite particles. Typically, to prepare battery grade graphite from natural graphite, the natural graphite is first ground and fractionated to obtain a powder with a desired size distribution (about 10-20 pm in diameter). The size fractionated powder is then rolled into spherical shapes with a roller. However, the efficiency of this rolling process is typically only 50-60%, resulting in a mixture of the desired rolled particles and fine particles with diameters less than 5 pm. The resulting mixture requires an additional fractionation step to separate the desired particles from the fine particles, which are typically disposed of as waste. Then, obviously, a significant amount of the starting natural graphite is lost.

[0005] Granulation is a process by which small particles can be agglomerated into larger particles. Granulation processes include wet and dry methods. Wet granulation methods include fluid bed, disc, drum, and mixer methods (e.g., by using pins, paddles, and / or blades). Such wet granulation methods require separation of the product particles from the liquid and can require additional binders or dispersants. Dry granulation methods include roller compaction, tableting, plunger / piston extrusion, marumerizer, radial extrusion, and axial extrusion. However, both wet and dry granulation methods are difficult to produce uniform product particles with diameters less than 100 pm, and the resulting product particles can often contain internal voids.

[0006] Other methods of producing micron-sized spherical or rounded particles include spray drying and prilling. In a spray drying process, a fluid containing a liquid (usually water) and suspended particulate and / or dissolved material is ejected from a nozzle to create droplets. The fluid can further contain additives such as wetting agents and binders. The droplets ejected from the nozzle are dried (e.g., by air flow) while still in the air, and then captured in a filter. This method can be expensive and wasteful, as the removal of the liquid in the drying step is often energy intensive, and the liquid is often lost as waste. The resulting powder is often porous and can require further processing (e.g., washing and filtering). Prilling is a method in which a molten liquid spray is solidified in flight. This method is only suitable for materials that can be formed in a molten state.

[0007] Thus, there is a need for a micron-sized dry granulation method (i.e., micropelletization) by which small particles (e.g., about 1 pm or less) can be agglomerated into larger, dense, and uniform micron-sized spherical or rounded particles, and which does not form a large amount of fine particle waste. However, according to US 9,132,482: “Very little literature is available on the granulation of inorganic nanosized powders, indicating the difficulty in conditioning inorganic nanosized powders into granular form.”

[0008] Physical methods employing dry processing are environmentally friendly and advantageous for industrial applications due to the elimination of the use of solvents. The mechanofusion (MF) process was developed in Japan in the 1980s and is based on the use of a high shear field to roll or dry coat powders without the use of any liquid (see T. Yokoyania, K. Urayama, and T. Yokoyama, KONA Powder Part. J., 1983, 1, 53-63). In the Li-ion battery field, MF is often used to roll natural graphite for use in the anode (e.g., US 9,142,832 or U.S. Patent Application No. 14 / 431,398).

[0009] MF, although useful in industry, is rarely reported in the literature. One reason can be that the use parameters of MF equipment are not widely known. Nonetheless, several publications describe particles that were rounded or coated with another phase by the MF process (e.g., M. Naito, M. Yoshikawa, T. Tanaka, and A. Kondo, KONA Powder Part. J., 1993, 11, 229-234; N. Product and M. Features, 1999, 17, 244-250; M. Alonso, M. Satoh, and K. Miyanami, Powder Technol., 1989, 59, 45-52; M. Naito, A. Kondo, and T. Yokoyama, ISIJ Int., 1993, 33, 915-924; R. Pfeffer, R. N. Dave, D. Wei, and M. Ramlakhan, Powder Technol., 2001, 117, 40-67; W. Chen, R. N. Dave, R. Pfeffer, and O. Walton, Powder Technol., 2004, 146, 121-136; and C.-S. Chou, C.-H. Tsou, and C.-I. Wang, Adv. Powder Technol., 2008, 19, 383-396). However, there are still very few publications that fully describe the preparation conditions of such engineered particles.

[0010] A type of graphitic material has been observed in the art that is of interest, referred to as "onion graphite". According to some literature, onion graphite refers to spheroidal or ovoid graphite particles in which the basal planes of the graphite are arranged in smooth concentric ovoid or spherical layers nested together with a common point at the core of the particle, and in which the alignment of the edges of the graphite layers does not extend outwardly from the central core (according to other literature, onion graphite refers only to perfect nested Buckyballs). In other words, the graphene layers in onion graphite are randomly positioned on the surface of the concentric nested spheres or ovoids, except that they are oriented so that their basal planes are tangent to the concentric nested spheres or ovoids. Onion graphite can be distinguished from the graphite spheroids in cast iron, which are known to have a microstructure in which the graphite basal planes are arranged concentrically, but the edges of the basal planes extend outwardly from the central core (e.g., as shown in Figure 6-4 of "Mesomolecules: From Molecules to Materials" SEARCH Series, Volume 1, G. David Mendenhall, Arthur Greenberg and Jeol F. Liebman (Editors), Chapman & Hall Publishers, New York, 1995). Onion graphite has been observed only in sizes up to 2 μιη. They have been found to form in interstellar space, as evidenced by their presence in meteorites. Nanoscale onion graphite has been produced only in small quantities by synthetic methods previously, such as by high-energy electron irradiation of carbon particles, annealing of nanodiamonds, electric arc discharge between two graphite electrodes immersed in water, carbon ion implantation into silver or copper substrates (e.g., see V. D. Blank, B. A. Kulnitskiy and I. A. Perezhogin, Scripta Materialia 60 (2009) 407-410). None of these methods are capable of producing particles in a highly graphitized state, in sizes greater than 2 μιη, in quantities that are economically feasible, i.e., in amounts greater than 1 gram. For example, U.S. Patent Application 2013 / 0189178 Al describes a method of making onion-shaped carbon, but the resulting carbon onions are only 6 nm in maximum size. Furthermore, no mention is made of the level of graphitization achieved.

[0011] Despite the continuing and substantial efforts worldwide to develop improved methods of manufacturing such materials, further improvements are needed. The present invention addresses these needs and provides further benefits as disclosed below.

[0012] SUMMARY

[0013] It has been discovered that certain high shear and high pressure field processes, such as dry mechanical fusion (MF), can be used in a simple manner and with great efficiency to prepare desired aggregates from a wide variety of precursor particles. The aggregated precursor particles ("product particles") can desirably be prepared to have a narrow particle size distribution and to have a smooth, spherical or rounded shape, free of cavities. In some aspects, cavities can be included within the product particles.

[0014] In particular, the product particles are prepared using a micro-pelletization process that includes obtaining a quantity of precursor particles having an average particle size of less than 1000 μm, obtaining a quantity of a template medium having an average particle size of less than 500 μm and a hardness greater than the precursor particles, and then preparing a mixture comprising the quantity of precursor particles and the quantity of template medium. The mixture is then subjected to a suitable high shear and high pressure field, such as that obtained by mechanical fusion, so that the precursor particles are aggregated into the desired product particles. The product particles can then be separated from the template medium, if desired for the intended application.

[0015] The foregoing process can be successfully used with a wide variety of types of precursor particles of a wide variety of characteristics. This includes precursor particles having an average size of less than 50 μm, and particularly less than 10 μm. Suitable precursor particle types include powders intended for use (either directly or after subsequent processing) in a battery electrode, a fertilizer, a pharmaceutical, a toner, a pigment, a filler, or a catalyst. As demonstrated in the examples below, suitable precursor particles include carbonaceous powders, mixed metal oxide powders, or metal carbonate powders, such as carbon, graphite flake, or LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2powder. Advantageously, mixed metal oxide powders used as precursor particles can be prepared by a full solid state process that includes ball milling a quantity of metal oxide raw material powders to produce the precursor particles. (For example, note that the precursor particles used in the examples below are not suitable for use in a battery electrode per se, but can be rendered suitable for such use by the micro-pelletization process and optionally by subsequent processing steps (e.g., by heating).) Additionally and generally, at least a portion of the quantity of precursor particles can be processed (including ball milling or heating) in some suitable manner prior to preparing the mixture.

[0016] While the process of the present invention desirably produces spherical and / or rounded aggregates, the starting precursor particles can be powders of a very irregular shape. Further, while the process of the present invention desirably produces powders having a narrow particle size distribution, the particle size distribution of the starting precursor particles can be very broad.

[0017] The resulting characteristics of the product particles vary in part as a function of the characteristics of the template medium employed. As mentioned, the template medium is harder than the precursor particles so as not to cause breakage of the former. Thus, suitable template media can be selected from the group consisting of zirconia, tungsten carbide, tungsten, silica, alumina, silicon nitride, hardened steel, stainless steel, and agate. To produce product particles of a desired size and shape, template media having an average size of 100 μm or less can be employed. In addition, the surface of the template medium can desirably be smooth and spherically shaped. Further, it is desirable that the size distribution of the template medium be uniform, e.g., such that (D90-D10) / D50 < 2, preferably (D90-D10) / D50 < 1, or more preferably (D90-D10) / D50 < 0.7. In addition, it can be desirable that the bulk volume of the amount of template medium employed be greater than the bulk volume of the amount of precursor particles employed, and in particular greater than or about three times the bulk volume of the amount of precursor particles.

[0018] A mechanical fusion system suitable for use in the method of the present application can include a chamber, a rotating wall within the chamber, a scraper within the rotating wall, and a press-head within the rotating wall. A representative gap between the scraper and the rotating wall can be about 0.5 mm. A representative gap between the press-head and the rotating wall can be about 1.4 mm. And a representative speed at which the rotating wall is rotated is a speed that results in a wall surface speed of about 8 m / s. In some embodiments, a mechanical fusion time of greater than or about 12 hours has proven to be successful. If template media from a coated precursor of a previous synthesis is reused in a new synthesis, a shorter processing time can be achieved. While the foregoing system produces product in batch form, it is advantageous that mechanical fusion can also be performed in a continuous manner (e.g., with suitable modifications to such a system).

[0019] In exemplary embodiments, product particles having an average size between 10 μm and 100 μm can be produced. Additionally, the size distribution of exemplary product particles can be sufficiently uniform such that (D90-D10) / D50 < 2. Still additionally, the surface of the product particles can be desirably smooth. In some aspects of the application, the product particles comprise particles having a roughness (as defined below) of less than 0.02, less than 0.01, less than 0.006, or even less. In some aspects of the application, all of the product particles have a roughness value of less than 0.02, less than 0.01, less than 0.006, or even less. In some aspects of the application, the product particles comprise particles that are substantially free of cavities. In some aspects of the application, all of the product particles are substantially free of cavities, and as demonstrated in the examples below, product particles of spherical or tetrahedral shape can be made.

[0020] Optionally, the complete production of product particles can additionally include an annealing step performed at high temperature (e.g. to recrystallize the particles after mechanical fusion).

[0021] Product particles produced according to the method of the application can be considered for a variety of commercial applications, including as battery electrodes, fertilizers, pharmaceuticals, toners, pigments, fillers, or catalysts. They can be particularly suitable for use as anodes or cathodes in rechargeable lithium batteries (e.g. lithium ion batteries).

[0022] Further, it was found that the above method can be used to produce novel structured graphite particles, lithium nickel manganese cobalt oxide particles, and lithium transition metal oxide particles.

[0023] In one aspect, a novel graphite particulate comprises a plurality of graphite particles, wherein the graphite particles are shaped as spheres or ovoids, and they comprise concentric nested spheres or ovoids of graphene layers. The graphene layers are randomly positioned on the surface of the concentric nested spheres or ovoids, except that the graphene layers are oriented such that their basal planes are tangent to the concentric nested spheres or ovoids. The graphite particles additionally have an average particle size greater than 2 μm and an average d spacing of less than 0.34 A. 002 In some embodiments, the graphite particles in the particulate comprise concentric layers of porosity, with voids or hollows near the core of the particles. In some embodiments, the graphite particles have an average particle size between 5 μm and 50 μm and a size distribution of (D90-D10) / D50 < 2.

[0024] In one aspect, a novel lithium mixed metal oxide particle comprises particles having a core of lithium nickel manganese cobalt oxide crystallites randomly oriented and having an average size of about 1 μιη, and coated with smaller randomly oriented lithium nickel manganese cobalt oxide crystallites having an average size of about 0.3 μιη.

[0025] The aforementioned novel lithium transition metal oxide particles comprise particles having at least two transition metals present in the group of Mn, Ni, and Co. In addition, the particles have an O3 structure, an average particle size from 1 μιη to 50 μιη, and they comprise crystallites of random shape and size throughout their interior. In certain embodiments, the crystallites have an average size greater than 0.5 μιη, and the average particle size of the particles is more than 5 times greater than the average crystallite size. In certain embodiments, the composition of one of the two transition metals can vary by at least 5 atomic % from the core of the particle to the shell of the particle.

[0026] The method can be used to make product particles having a uniform composition, but can also be used to make product particles having different compositions near their core than near their surface. The precursor particles employed can be single phase, or they can be composed of a mixture of particles having different characteristics. For example, the precursor particles can be composed of a mixture of first particles having a first composition and second particles having a second composition, where the first and second compositions are different and / or the first and second particles comprise crystallites having different average crystallite sizes (e.g., where the average crystallite size of the first precursor particles differs from the average crystallite size of the second precursor particles by at least 10%).

[0027] Precursor particles suitable for forming graphite product particles include graphitizable carbons such as natural graphite, coke, and soft carbon. Precursor particles suitable for forming product particles that can be used as cathode materials in Li-ion batteries include hydroxides, oxides, sulfates, nitrates, and carbonates of lithium, aluminum, manganese, transition metals, and mixtures thereof. In the case of lithium nickel manganese cobalt oxide product particles, suitable precursor particles are lithium nickel manganese cobalt oxide particles. In the case of lithium transition metal oxide product particles, suitable precursor particles are lithium transition metal oxide particles. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A mechanical fusion system suitable for use in the micro-pelletization process of the present application is schematically illustrated.

[0029] Figure 2a and 2b SEM images of the ZrO2 template medium used in the examples are shown at two different magnifications.

[0030] Figure 2cA cross-section of a Zr02 particle is shown, with its perimeter and centroid indicated. Figure 2d A plot of the residual of the interpolated radial segment value versus the interpolated f(x) value as a function of x is shown.

[0031] Figure 3 A particle size distribution of the Zr02 template medium used in the example is shown.

[0032] Figure 4a and 4b SEM images of graphite sheet precursor particles used in the example are shown at two different magnifications.

[0033] Figure 5a and 5b SEM images of the product obtained after mechanical fusion of a mixture of graphite sheet precursor particles and Zr02 template medium are shown at two different magnifications.

[0034] Figure 6a and 6b SEM images of graphite sphere product particles from Figure 5a and 5b after separation from the Zr02 template medium are shown at two different magnifications.

[0035] Figure 7a , 7b and 7c show XRD patterns between 20° and 65° for graphite sheet precursor particles before mechanical fusion, graphite sphere product particles after mechanical fusion and separation from the template medium, and graphite sphere product particles after annealing, respectively.

[0036] Figure 8 A particle size distribution of graphite sphere product particles after annealing is shown. For comparison, the particle size distribution of the Zr02 template medium (dashed line) is also shown.

[0037] Figure 9a , 9b and 9c show electrochemical performance of a battery cell comprising graphite sphere product particles of the application. In these figures, the voltage profile, the corresponding differential capacity profile, and the cycling performance are shown, respectively.

[0038] Figure 10a , 10b and 10c show various SEM images of a cross-section graphite sphere product particle. Figure 10a A complete cross-section of a product particle is shown, while Figure 10b and 10c different parts of a product particle are shown at a greater magnification.

[0039] Figure 10d A cross-section of a graphite sphere product particle is shown, revealing its perimeter and centroid. Figure 10e The graph shows the residuals of the interpolated radial segment values ​​versus the interpolated f(x) values ​​as a function of x, the product particle.

[0040] Figure 11a and 11b SEM images of NMC precursor particles synthesized using an all-solid-state method and used in the example are shown at two different magnifications.

[0041] Figure 12a and 12b SEM images of the product obtained by mechanically fusing a mixture of NMC precursor particles and ZrO2 template medium are shown at two different magnifications.

[0042] Figure 13a and 13b Shown at two different magnifications Figure 12a and 12b SEM images of tetrahedral NMC product particles separated from the ZrO2 template medium.

[0043] Figure 14a , 14b Figures 14c show the XRD patterns of NMC precursor particles before mechanical fusion, tetrahedral NMC product particles after mechanical fusion and separation from the template medium, and NMC product particles after annealing, respectively, at 10° and 80°.

[0044] Figure 15 The particle size distribution of the NMC product after annealing is shown. For comparison, the particle size distribution of the ZrO2 template medium is also shown (dashed line).

[0045] Figure 16a and 16b The electrochemical performance of a battery cell containing NMC product particles of the present invention is shown. Voltage curves and cycle performance are displayed in these figures.

[0046] Figure 17a , 17b Images 17c and 17d show various SEM images of cross-sectional NMC product particles. Figure 17a The complete cross-section of the product particles is shown, while Figure 17b , 17c The 17d model shows different portions of the product particles at several greater magnifications.

[0047] Figure 17e A cross-section of an NMC product particle is shown, revealing its perimeter and centroid. Figure 17fA plot showing the residuals of the interpolated radial segment values versus the interpolated f(x) values as a function of x for product particles.

[0048] Figure 18a and 18b An SEM image of comparative NMC particles after long-term automated milling is shown.

[0049] Figure 19 Various dimensions related to characterizing particle surface cavities from particle cross-sectional or projected area are shown.

[0050] Figure 20a and 20b An SEM image of cross-sectional core-shell product particles of Example 3 of the invention is shown.

[0051] Figure 21 An SEM image of cross-sectional core-shell product particles of Example 3 of the invention is shown.

[0052] Figure 22 An XRD pattern of shell precursor particles of Example 4 of the invention is shown.

[0053] Figure 23 An SEM image of shell precursor particles of Example 4 of the invention is shown.

[0054] Figure 24 An XRD pattern of intermediate A of Example 4 of the invention is shown.

[0055] Figure 25 An SEM image of intermediate A of Example 4 of the invention is shown.

[0056] Figure 26 An SEM image of core precursor particles of Example 4 of the invention is shown.

[0057] Figure 27 An XRD pattern of core precursor particles of Example 4 of the invention is shown.

[0058] Figure 28a and 28b An SEM image of cross-sectional core-shell product particles of Example 4 of the invention is shown.

[0059] Figure 29 An SEM image of cross-sectional core-shell product particles of Example 4 of the invention is shown.

[0060] Figure 30a An SEM image of cross-sectional core-shell product particles of Example 4 of the invention is shown.

[0061] Figure 30b EDS elemental mapping of Ni for cross-sectional core-shell product particles of Example 4 of the invention is shown.

[0062] Figure 31 XRD pattern for product particles of Example 4 of the invention is shown.

[0063] Figure 32 XRD pattern for heated product particles of Example 4 of the invention is shown.

[0064] Figure 33 SEM image of a cross-section of heated product particles of Example 4 of the invention is shown.

[0065] Figure 34 Cross-sectional image of heated core-shell product particles of Example 4 of the invention is shown, with the locations of the five points labeled as spectra 1-5 (from left to right), with the composition obtained by EDS.

[0066] Figure 35 Transition metal composition of heated product particles of Example 4 of the invention as a function of distance from the surface of the particle is shown.

[0067] Figure 36 SEM image of a cross-section of heated product particles of Example 5 of the invention is shown.

[0068] DETAILED DESCRIPTION

[0069] Unless the context requires otherwise, throughout the present specification and claims, the word "comprise", and variations thereof (such as "comprising" and "comprises") means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

[0070] Furthermore, the following definitions apply throughout this patent document:

[0071] The term "high shear and high pressure field" herein refers to shear and pressure conditions similar to those experienced in typical mechanical fusion processes.

[0072] The term "irregularly shaped" for a plurality of particles is intended to refer to individual particles that are irregularly shaped, but also to a mixture of particles that have regular shapes but are not of a common shape.

[0073] The particle size distribution of a given sample is quantified herein by its "Dn" diameter. This is conventionally defined as the diameter at which n% of the sample mass has a smaller particle size.

[0074] The term "average size" of a population of particles is thus defined as its D50 diameter.

[0075] The term "projected area diameter" of a particle is the diameter of a circle having the same area as the projected image (i.e. silhouette) of the particle or the cross section of the particle where the cross section passes near the centroid of the particle.

[0076] The term "cavity" or "cavities" is used to refer to a depression on the surface of a particle having a relative depth in the range of 0.02 to 0.1 and a relative aspect greater than 0.2. Methods for quantifying relative depth and relative aspect are provided under "Material Characterization" in the Examples section below.

[0077] The term "roughness" is used to refer to the coefficient of variation determined by the spline variation method described under "Material Characterization" in the Examples section below.

[0078] The term "smooth" refers to a particle having a roughness less than 0.02.

[0079] The term "spherical" is used to refer to a particle whose surface is no more than 25% from the distance of the centroid of the particle.

[0080] The term "granule" refers to a population of particles or aggregated particles.

[0081] In a quantitative context, the term "about" should be interpreted as being within a range of up to plus 10% and down to minus 10%.

[0082] The term "anode" refers to the electrode where oxidation occurs when a metal-ion battery cell is discharging. In a lithium-ion battery cell, the anode is the electrode that de-lithiates during discharge and lithiates during charge.

[0083] The term "cathode" refers to the electrode where reduction occurs when a metal-ion battery cell is discharging. In a lithium-ion battery cell, the cathode is the electrode that lithiates during discharge and de-lithiates during charge.

[0084] The term "metal-ion battery cell" or "metal-ion battery" refers to an alkali metal particle battery cell, including lithium-ion battery cells and sodium-ion battery cells.

[0085] The term "half-cell" refers to a battery cell having a working electrode and a metal counter / reference electrode. A lithium half-cell has a working electrode and a lithium metal counter / reference electrode.

[0086] The term "active material" refers to a material capable of reversibly storing metal ions in the anode or cathode.

[0087] The term "anode active material" or "anode material" refers to an active material used to reversibly store metal ions in the anode. In a Li-ion battery cell, the anode material intercalates lithium during charging and deintercalates lithium during discharging at a potential vs. Li of less than 2 V. In a lithium half-cell, the anode material deintercalates lithium during charging and intercalates lithium during discharging at a potential vs. lithium of less than 2 V.

[0088] The term "cathode active material" or "cathode material" refers to an active material used to reversibly store metal particles in the cathode. In a Li-ion battery cell, the cathode material intercalates lithium during charging and deintercalates lithium during discharging at a potential vs. Li of more than 2 V. In a lithium half-cell, the cathode material deintercalates lithium during charging and intercalates lithium during discharging at a potential vs. lithium of more than 2 V.

[0089] The term "cross-section" is understood to mean a cross-section through the center of gravity of the particle.

[0090] The term "average crystallite size" refers to the grain size of a phase as determined by the Scherrer crystallite size determination method described in more detail below. (Note that in principle, the average crystallite size can not only be determined by X-ray diffraction techniques, but also from SEM images). In the former, which is referred to as the Scherrer grain size determination method, the Scherrer equation is applied to the X-ray diffraction peak FWHM of any one of the X-ray powder diffraction peaks of a phase between 20° and 60° 2-theta under Cu-Kal incident radiation. A description of the Scherrer equation can be found in B. E. Warren, "X-ray Diffraction", Dover Publications, 1990. In the latter, the average crystallite size is determined from the average of the crystallite sizes of a randomly sampled crystallites observed by scanning electron microscopy.

[0091] In the present text, the term "O3 phase" refers to a phase having an alpha-NaFe02-type structure, as described in C. Delmas, C. Fouassier and P. Hagenmuller, Physica, 99B (1980) 81-85. As an example, LiCo02, which is widely used as an active positive electrode material in commercially available Li-ion batteries, has an O3 structure. X-ray diffraction can be used to determine the structure of the phases in a sample, including if the material comprises a phase having an O3 structure or a phase having a graphite structure.

[0092] It has been discovered that uniform aggregates can be produced from a variety of precursor particles using high shear and high pressure fields associated with the mechanical fusion (MF) dry processing method. The MF process is relatively simple and inexpensive. Most of the precursor particles are incorporated into the product particles, and thus the precursor particles are fully utilized. Additionally, the MF process is a dry process, which does not require solvents, making it potentially attractive for environmentally responsible commercial manufacturing. The only steps required are to obtain the appropriate amounts of precursor particles and template media, and to mechanically fuse the mixture of precursor particles for a sufficient time to properly produce aggregate particles. After the mechanical fusion processing, the product particles can be separated from the template media by air classification, sieving, cyclone, elutriation, sedimentation, hydrocyclone, or other known wet or dry methods that separate particles based on size, shape, or density.

[0093] Figure 1 A suitable MF system 1 for making particles according to the method of the present application is shown schematically. It consists of a rotating cylindrical vessel 2 and a fixed rounded ram 3 and a fixed scraper 4 placed within it. The ram 3 has a radius smaller than the radius of the chamber 2, and the clearance space between the ram 3 and the chamber wall 5 is typically in the range from 1 mm to 5 mm. The clearance between the scraper 4 and the chamber wall 5 is smaller, typically around 0.5 mm. Preferably, these clearances can be adjusted according to factors such as chamber size, particle size, powder hardness, etc., in order to optimize.

[0094] The operation of the MF system 1 is simple, but the mechanism of processing the powder within the chamber is complex (see W. Chen, R. N. Dave, R. Pfeffer, and O. Walton, Powder Technol., 2004, 146, 121-136). In use, a powder mixture 6 (containing the appropriate amounts of precursor particles and template media) is placed in the chamber, and the chamber 2 is sealed. As the chamber is rotated, the powder mixture 6 is pushed by centrifugal action towards the chamber wall 5. This also forces the powder mixture through the converging space between the fixed ram 3 and the rotating chamber wall 5, establishing a high shear and high pressure field. As the powder particles emerge from the diverging space of the ram region, they adhere to each other and to the chamber wall. The scraper 4 serves to scrape the powder adhered to the chamber wall 5. The sheared powder mixture is then re-dispersed into the chamber and moves again towards the ram region. The powder undergoes this compression, frictional shear, and de-agglomeration continuously as the chamber 2 is rotated. These interactions result in a variety of effects, including rounding, small particles or soft particles coating on large particles, and small particles embedding in large particles. These effects occur rapidly at the high rotational speeds (>1000 rpm or wall surface velocity greater than about 8 m / s) typically employed.

[0095] Those skilled in the art will appreciate that the appropriate operating parameters for the MF system can be expected to vary depending on the product particles desired and the types and amounts of precursor particles and template medium employed. It is expected that those skilled in the art will be able to determine appropriate operating parameters for a given situation based on the guidance provided in the examples below.

[0096] The method of the present invention can be used to aggregate a wide variety of types of precursor particles into larger, uniform product particles. In principle, any precursor particles having an average particle size of less than 1000 μιη can be aggregated. (Note: it is in principle possible to start with larger particles up to 1000 μιη, as it is expected that they will be reduced in size during processing. Thus, precursor particles larger than the template medium can be employed. Such particles can be milled in situ to smaller sizes during processing.) The method is particularly suitable for the production of product particles having an average size of less than 100 μιη, even smaller (e.g. less than 50 μιη or even less than 10 μιη).

[0097] As demonstrated in the examples below, powders for battery electrodes can be aggregated by the method of the present invention. Such precursor powders include both anode active materials and cathode active materials, such as carbonaceous powders (e.g. graphite flakes) or conventional mixed metal oxide powders (e.g. NMC or LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2powders). Suitable precursor powders also include mixed metal oxide powders prepared in an unconventional manner, such as those prepared using the novel all-solid-state method in which an appropriate mixture of metal oxide feedstock powders is ball-milled to produce mixed metal oxide precursor particles. However, in addition, it is expected that similar aggregates of powders commonly intended for use as fertilizers, pharmaceuticals, toners, pigments, fillers or catalysts in other industrial applications can also be readily prepared in a similar manner. A useful feature of the method of the present invention is that there are no special requirements on the shape or particle size distribution of the starting precursor particles in order to obtain the desired final product. The precursor particles can have regular shapes, alternatively can be irregularly shaped powders, and can have narrow, broad or multiple modal size distributions.

[0098] The microgranulation process of the present invention generally involves preparing a mixture of a selected amount of precursor particles with an appropriate amount of a templating medium. The templating medium generally has an average particle size of less than 500 μm and is selected to have a hardness greater than that of the precursor particles. In this way, the templating medium does not itself break down under the high shear and pressure conditions involved in the process. Suitable material selections for the templating medium include zirconia, tungsten carbide, tungsten, silica, alumina, silicon nitride, hardened steel, stainless steel, and agate. Additionally, the templating medium preferably has a regular, smooth, and spherical shape, as otherwise it will more easily break down, particularly into spheres, during processing, thereby contaminating the final product.

[0099] The size, uniformity, and amount of the templating medium employed can also be important for the characteristics of the desired final product particles. The aggregate final product particles are expected to be slightly smaller than, but approximately equal to, the size of the templating medium used. Thus, for smaller aggregates, it can be desirable for the average particle size of the templating medium to be less than 100 μm. Additionally, the uniformity of the final product particles is expected to be generally similar to the uniformity of the templating medium used. Thus, for a desirably uniform final product, it can be desirable for the size distribution of the templating medium to be sufficiently uniform such that (D90-D10) / D50 < 2, preferably (D90-D10) / D50 < 1, more preferably (D90-D10) / D50 < 0.7, or even more preferably (D90-D10) / D50 is even less. Additionally, a sufficient amount of the templating medium should be employed in the process to adequately and successfully process all of the precursor particles present. To this end, in some embodiments, the bulk volume of the amount of templating medium is desirably greater than the bulk volume of the amount of precursor particles. More specifically, when a uniform spherical templating medium is employed, the relative amounts in the mixture are preferably selected such that the volume of precursor particles can enter the interstitial volume present between randomly packed templating medium spheres (which is approximately 1 / 3 of the bulk volume of the spheres). Thus, a 1 :3 bulk volume ratio of small precursor particles to templating medium can be preferred (i.e., the bulk volume of the amount of templating medium is preferably greater than or approximately three times the bulk volume of the amount of precursor particles).

[0100] The microgranulation process itself involves subjecting the appropriate mixture comprising the amount of precursor particles and templating medium to mechanical fusion, or other comparable high shear and high pressure fields. This step serves to aggregate the precursor particles into product particles. Mechanical fusion can be performed, for example, in a ball mill, attritor mill, or other comparable device. The mechanical fusion process is expected to be a function of the size of the precursor particles and the amount of the templating medium. For example, for smaller precursor particles, it can be desirable to employ a smaller amount of the templating medium, and vice versa. In some embodiments, the amount of the templating medium is desirably less than 50% by volume of the amount of precursor particles, preferably less than 20% by volume of the amount of precursor particles, and more preferably less than 10% by volume of the amount of precursor particles. In other embodiments, the amount of the templating medium is desirably greater than 50% by volume of the amount of precursor particles, preferably greater than 70% by volume of the amount of precursor particles, and more preferably greater than 90% by volume of the amount of precursor particles. Figure 1The representative processing settings include a gap between the spatula and the rotating wall of about 0.5 mm and a gap between the ram and the rotating wall of about 1.4 mm. Representative rotation speeds are about 1000 rpm and higher, which results in a wall surface speed of about 8 m / s or higher. Mechanical consolidation processing times of greater than or about 12 hours have proven to be sufficient. Shorter processing times can be achieved when using different sample volumes, rotation speeds, powder ratios, or if the template medium is recycled.

[0101] In the mechanical consolidation process, the precursor particles and the template particles are in a vacuum or a fluid environment, typically a gaseous atmosphere. In simple embodiments, the gaseous atmosphere is air. In other embodiments, however, the gaseous atmosphere can be an inert gas, such as argon or nitrogen. Additionally, the gaseous atmosphere can be reducing and can include hydrogen or ammonia, for example, a mixture of 5% hydrogen and 95% nitrogen. Additionally, the gaseous atmosphere can be oxidizing and can include an oxidizing gas, such as oxygen or carbon dioxide.

[0102] While Figure 1 The mechanical consolidation system shown in FIG. 1 and discussed above is used to produce product particles in a batch process, but the apparatus can be modified so that production can instead be performed continuously. For example, during mechanical consolidation, the particles can be continuously removed from the mechanical consolidation machine in the form of a particle stream. The desired product particles can then be separated from the particle stream by a continuous classification process and collected. The remaining unprocessed precursor particles and template medium in the particle stream can then be returned to the mechanical consolidation machine. Additional precursor particles can also be continuously added to the mechanical consolidation machine to replace the product particles removed by classification. In this manner, product particles can be continuously produced and collected.

[0103] After the mechanical consolidation or equivalent processing step is complete, the product particles are then separated from the template medium. This can be accomplished in a variety of ways. For example, if the product particles and the template medium are sufficiently uniform but different in size, adequate separation can be achieved simply by sieving. As an alternative, if the product particles and the template medium are sufficiently different in density, density separation techniques can be employed (e.g., as shown in the examples, dense Zr02microspheres were used as the template medium and were then easily separated from the much less dense product particles using density separation techniques). Methods of separating product particles from template medium include air classification, sieving, cyclone separators, elutriation, sedimentation, hydrocyclones, or other known wet or dry methods of separating particles based on size, shape, or density.

[0104] It has been observed that, because of the mechanical handling involved in this method, some loss of crystallinity of the precursor particles can occur. If desired and / or required, this loss can be easily corrected by annealing (heating) the product particles at high temperature and in an environment appropriate to the materials involved (e.g. an inert atmosphere for carbonaceous powders, or air for oxide powders).

[0105] In some embodiments, the synthesis of the precursor particles can include a step to reduce the average particle size, such as by milling (including ball milling) or classification. In some embodiments, the synthesis of the precursor particles can include a step to reduce the crystallite size, including ball milling. In some embodiments, the synthesis of the precursor particles can include a step to increase the crystallite size, including a heating step or a classification step. In some embodiments, the synthesis of the precursor particles can include a step to react more than one component together, including co-precipitation, heating, ball milling, or other known methods. In some embodiments, the synthesis of the precursor particles can include a step to combine particles having different average crystallite sizes and different compositions together.

[0106] In some embodiments, the above micro-pelletization method is applied to template particles and precursor particles (including a mixture of precursor particles having different crystallite sizes), the resulting product particles have, on average, larger precursor particle crystallites near the core of the product particle and smaller precursor particle crystallites near the surface of the product particle. Also, in some embodiments, if a mixture of precursor particles having different chemical compositions is used, and the average crystallite size of the precursor particles of one composition in the mixture is larger than the average crystallite size of the precursor particles of another composition in the mixture, then product particles are obtained in which the composition of the core of the product particle is very close to the composition of the precursor particles having the larger crystallite size, and the composition of the surface of the product particle is very close to the composition of the precursor particles having the smaller crystallite size. In theory, by applying the above method to a mixture of template particles and precursor particles, in which the precursor particles comprise a mixture of precursor particle powders having different compositions and average crystallite sizes, product particles having a continuously varying composition can be produced, such that the composition of the product particle changes from the surface to the core of the product particle in the order of increasing average crystallite size of each precursor particle powder.

[0107] The precursor particles can also comprise particles having different compositions, such that a composite product particle comprising an aggregated mixture of precursor particles having different compositions is produced. In some embodiments, the composite product particle can be heated, such that the precursor particle components react with each other.

[0108] In this manner, product particles having an average size between 10 μm and 100 μm can be produced. Additionally, the product particles can be quite uniform in size, having a narrow particle size distribution similar to that of the template medium employed. For example, the product particles can be uniform in size such that (D90-D10) / D50 < 2, (D90-D10) / D50 < 1, (D90-D10) / D50 < 0.7, or even less. Still further, the product particles can desirably be smooth and formed into regular, rounded shapes, such as spheres and rounded tetrahedrons. The product particles can further be free of features having a relative depth in the range of 0.1 to 0.2 and a relative aspect ratio greater than 0.2.

[0109] Once produced in the foregoing manner, the product particles are generally ready for routine use in their intended applications. In battery applications, electrodes and electrochemical devices can be produced from the product particles in a number of ways known to those skilled in the art. For example, there are a number of optional designs and methods for producing electrodes for rechargeable lithium-ion batteries and for producing the batteries themselves, and these have been well documented in the art.

[0110] It has been discovered that the mechanical consolidation process is effective in producing uniform, rounded aggregates in this manner, while other conventional granulation processes, such as autogenous grinding and ball milling processes, are not. Without wishing to be bound by theory, in the present process it is believed that the precursor particles initially coat the template medium. However, because the template medium is smooth, the precursor particles do not adhere well to the template medium. Thus, after a certain thickness is reached, the layer of precursor particles peels off the template medium. This results in the formation of intermediate particles having a relatively uniform volume. These intermediate particles are then rounded to form the product particles. This process thus relies on the ability of the mechanical consolidation process to form a dense coating on the particles. This is only possible in the high shear and high compression fields present during the mechanical consolidation process. Other processes, such as grinding, attrition milling, and high shear mixing, have been found not to have this property, and thus do not produce equivalent product particles.

[0111] Another discovery associated with the present process is that some of the product particles that can be produced have novel, potentially useful structures. These include graphite product particles, lithium mixed metal oxide product particles, and lithium transition metal oxide product particles having unique structures. For example, graphite particles can be produced that include graphite particles shaped as spheres or ovoids, and that include concentric nested spheres or ovoids of graphene layers. These graphene layers are randomly positioned on the surface of the concentric nested spheres or ovoids, except that the graphene layers are oriented such that their basal planes are tangent to the concentric nested spheres or ovoids. The graphite particles can additionally have an average particle size greater than 2 μm and an average d of less than 0.2.002 spacing. In some embodiments, the graphite particles in the particulate comprise concentric layers of porosity with voids or hollows near their core. In some embodiments, the graphite particles have an average particle size between 5 pm and 50 pm and a size distribution of (D90-D10) / D50 < 2.

[0112] The aforementioned graphite particles and highly graphitic onion-type graphites are expected to be advantageous for use as active negative electrode materials in Li-ion batteries. It is well known that the basal planes of graphite are sites of high reactivity with Li-ion battery electrolytes. Therefore, natural graphites are typically tumble-rounded to reduce the surface area of the basal planes that contact the electrolyte, as discussed in M. Yoshio et al., J. Mater. Chem. 14 (3005) 1754-1758. However, the conventional tumble- rounding process results in the graphite planes being rolled into spirals, which are arranged like a jelly roll, or as described by M. Yoshio et al.: "The spherical natural graphite particles look like clenched fists." In other words, the graphite layers in conventionally tumble-rounded natural graphite particles are arranged concentrically around a central axis (i.e., nested concentric cylinders), rather than concentrically around a point, as in the case of onion-type graphites (i.e., nested concentric spheres or ovoids). Although the arrangement of the graphite basal planes in spherical natural graphite can reduce the amount of graphite basal planes exposed to the electrolyte, the graphite basal planes are still exposed at either end of the "jelly roll." To reduce the reactivity of the exposed basal planes, spherical natural graphite is typically coated with carbon, as described by M. Yoshio et al. In contrast, the microstructure of onion-type graphites has no basal planes exposed to the electrolyte, and therefore is expected to have improved performance as a negative electrode material in Li-ion batteries. Onion-type graphites are also expected to be superior to the graphite sphere type seen in cast iron, which is known to have a microstructure in which the graphite basal planes are arranged concentrically, but these basal planes extend outward from a central core (e.g., as shown in Figure 6-4 of "Mesomolecules: From Molecules to Materials" SEARCH Series, Volume 1, G. David Mendenhall, Arthur Greenberg, and Jeol F. Liebman (Editors), Chapman & Hall Publishers, New York, 1995). In this configuration, the electrolyte is expected to reach the graphite basal planes along radial lines that are separated from the basal planes by the core of the particle from the surface. To be practical for use in Li-ion battery applications, the onion-type graphites should be greater than 5 μm in size, or more preferably between 10 μm and 50 μm in size. Furthermore, the onion-type graphites should have a high level of graphitization, which is known to improve reversible capacity and reduce cell polarization. One measure of the level of graphitization is the d 002 spacing of the graphite, which is measured by x-ray diffraction, where the lower the value of the d 002 spacing, the greater the degree of graphitization. An indicator of a preferred level of graphitization is a median d 002 spacing of less than or more preferably less than or even more preferably less than

[0113] Also, for example, lithium mixed metal oxide particles can be made that contain particles having a core of lithium nickel manganese cobalt oxide crystallites randomly oriented and having an average size of about 1 μιη, coated with smaller randomly oriented lithium nickel manganese cobalt oxide crystallites having an average size of about 0.3 μιη. In some embodiments, the lithium mixed metal oxide product particles are in the form of smooth tetrahedrons.

[0114] Also, for example, lithium transition metal oxide particles can be made that contain particles having at least two transition metals present in the group consisting of Mn, Ni, and Co. These particles have an O3 structure, an average particle size from 1 μιη to 50 μιη, and they contain crystallites of random shape and size throughout their interior. In certain embodiments, the crystallites have an average size greater than 0.5 μιη, and the average particle size of the particles is more than 5 times greater than the average crystallite size. In certain embodiments, the composition of one of the two transition metals can vary by at least 5 atomic % from the core of the particle to the shell of the particle.

[0115] The following examples illustrate certain aspects of the application, but should not be construed as limiting the application in any way. Those skilled in the art will readily understand other modifications to the methods and materials described herein.

[0116] Example

[0117] Exemplary particles were made by using mechanical fusion to aggregate precursor particles according to the application. Other particles were also made for comparison purposes. Various characteristics of these particles were determined and presented below. In addition, electrodes and electrochemical cells were made using some of these particles. Cell performance results obtained from the electrochemical cells were also presented below.

[0118] Micro-pelletization process (mechanical fusion)

[0119] In the following, a Figure 1 Micro-pelletization was accomplished using an AM-15F mechanical fusion system (Hosokawa Micron Corporation, Osaka, Japan) schematically depicted in FIG. 1. The equipment was modified by replacing the standard stainless steel chamber, doctor blade, and identical parts made of hardened steel to reduce wear. The chamber had an inner diameter of 15 cm. Unless otherwise indicated, mechanical fusion was performed at high rotational speed with a doctor blade / wall gap of 0.5 mm and a ram / wall gap of 1.4 mm. After a given process time, samples were collected from several different areas in the chamber. Unless otherwise indicated, the gas atmosphere used during mechanical fusion processing was air.

[0120] Material Characterization

[0121] Particle size distribution of the particulate samples was obtained using a Horiba Partica LA-950V2 laser scattering particle size distribution analyzer.

[0122] X-ray diffraction (XRD) patterns were collected using a Rigaku Ultima IV diffractometer equipped with a Cu Ka X-ray source, diffracted beam graphite monochromator, and scintillation detector.

[0123] The average crystallite size of different phases was determined by applying the Scherrer equation to the largest XRD peak of the phase of interest, unless otherwise indicated.

[0124] SEM and cross-section SEM were used to study the sample morphology. For this purpose, a TESCAN MIRA3 LMU variable pressure Schottky field emission scanning electron microscope (SEM) was used. Cross-sections of the samples were prepared with a JEOL cross-section polisher (JEOL Ltd., Tokyo, Japan) by sputtering argon ions against the sample to section the sample.

[0125] To characterize the surface cavities of the particles, the relative depth and relative aspect ratio of the depressions on the particle surface were measured from the particle cross-section or projected area (i.e. silhouette) as follows. As shown in Figure 19 A line AB is drawn over the depression on the particle surface, with both ends tangent to the particle surface. The longest distance (line GC) measured perpendicular from line AB to the particle surface is called the feature depth d. Two lines are drawn from point C such that they touch the surface at line AB and have the largest possible acute angle between them without penetrating into the particle volume (lines EC and CF in Figure 19 The relative depth of the particle is defined as d / D, where D is the projected area diameter. The relative aspect ratio is defined as {(EC+FC) / EF-1}. Surface cavities are those features that have both a relative depth in the range of 0.02 to 0.1 and a relative aspect ratio greater than 0.2.

[0126] Particle roughness is determined using the spline variate method. In this method, particle roughness is determined by quantifying the variation in surface radius measured from the centroid. In this method, a scanning electron microscope (SEM) digital image of the cross-section or silhouette of the desired particle is obtained, with the image having a minimum resolution such that there are at least 1000 image pixels across the perimeter of the particle. After 1000 or more profile pixels of the SEM image have been determined, the centroid of the silhouette of the apparent profile is found. Next, the distance from each point on the silhouette of the apparent profile to the centroid, i.e., the "radial segment value," is measured. The radial segment values are then plotted as a function of the angle about the centroid between 0° and 360°, and this plot is fitted with a smooth spline function where x i is the angle value, Y i is the radial segment value, f(x) is a cubic smooth spline function (as described on page 17 of P.J. Green, Bernard W. Silverman, Nonparametric Regression and Generalized Linear Models: A Roughness Penalty Approach, 1994 copyright, P.J. Green and B.W. Silverman, CTC Press, 2000 reprint), and λ is a smoothing parameter, which is generally greater than or equal to zero, but in this case is fixed at 999. The number of radial segment values is then reduced to 1000 by linear interpolation such that each interpolated radial segment value associated with a particular angle x is calculated as the average of the only radial segment values closest to that angle of the maximum number. The number of f(x) values is also reduced to 1000 by linear interpolation in the same manner such that for each interpolated radial segment value, there is an interpolated f(x) value at the same x value. The coefficient of variation is then determined as the standard deviation divided by the average radius of the interpolated radial segment values, with the interpolated f(x) values determined as a function of x. The coefficient of variation is considered equivalent to the surface roughness, which has a value always greater than or equal to zero (i.e., zero is the roughness of a perfect circle). The greater the coefficient of variation, the rougher the particle.

[0127] Electrode preparation

[0128] Sample electrodes for laboratory testing were prepared from slurries prepared by mixing the particles prepared, carbon black (Super C65, Imerys Graphite and Carbon) and lithium polyacrylate (LiPAA, LiPAA provided in a 10 wt% solution in water prepared by neutralising a solution of polyacrylic acid (Sigma Aldrich, average molecular weight approximately 250,000 g / mole, 35 wt% in H2O) with a solution of LiOH H2O (Sigma Aldrich, 98%) in distilled water) in a volume ratio of active particles / carbon black / LiPAA of 70 / 5 / 25, where the volumes are determined on a tap density basis, in distilled water. The slurries were mixed for one hour using a Retsch PM200 planetary ball mill with three 13 mm tungsten carbide balls at 100 rpm, then spread onto metal foils (copper foil or aluminium foil for anode active material and cathode active material respectively) using a coating bar with a 0.004 inch gap. The coatings were then dried in air at 120°C for 1 hour, cut into 1.3 cm discs, then heated under vacuum at 120°C for 1 hour, without further exposure to air. The resulting electrode loading was approximately 2-2.5 mg / cm 2 .

[0129] Battery cell preparation

[0130] To evaluate these different materials as electrode materials in Li-ion battery cells, lithium-ion half battery cells for laboratory testing were constructed and tested. The electrodes were assembled in 2325 type coin lithium half battery cells with lithium foil (99.9%, Sigma Aldrich) counter electrode / reference electrode. (Note: As is well known to those skilled in the art, the results obtained from these lithium half battery cells for testing can be used to reliably predict the performance of the electrode materials in lithium-ion batteries.) Two layers of Celgard 2300 separator were used in each coin lithium half battery cell. A 1 M solution of LiPF6 (BASF) in a solution of ethylene carbonate, diethyl carbonate and monofluoroethylene carbonate (volume ratio 3:6:1, all from BASF) was used as electrolyte. The assembly of the battery cells was carried out in an argon filled glove box. The battery cells were cycled at constant current at 30.0°C ± 0.1 °C.

[0131] Inventive Example 1 - Micro-Granulation of Graphite Flakes

[0132] Zirconium oxide (Zr02) microspheres (Glen Mills Inc.) with an average size (diameter) of 57 pm were used as a templating medium to aggregate the graphite flake precursor particles into graphite product particles. Figure 2a and 2bSEM images of the ZrO2 template medium are shown at two different magnifications. Figure 2c A cross-section of a ZrO2 particle is shown, with its perimeter and centroid indicated. Figure 2d A plot of the residuals of the interpolated radial segment values versus the interpolated f(x) values as a function of x is shown. From this data, the roughness is determined. The ZrO2 template medium is smooth, with a roughness of only 0.0022, and no cavities. Figure 3 A uniform particle size distribution of the ZrO2 template medium is shown, with a D50 of 57.35 μm and (D90-D10) / D50 = 0.61.

[0133] Natural graphite flakes (230U, Asbury Graphite Mills Inc.) were used as the graphite precursor particles. Figure 4a and 4b SEM images of these precursor particles are shown at two different magnifications. It is clear from these images that the graphite flakes are irregularly shaped particles with a layered structure, and that the particles vary greatly in size. Many of the particles have jagged surface features, which are large cavities.

[0134] A mixture containing approximately 225 g of ZrO2 microspheres template medium and approximately 25 g of graphite precursor particles (approximately 50 mL total powder volume) was prepared and then subjected to high shear and high pressure fields provided by the aforementioned mechanical consolidation system. The system was run at 1500 rpm (12 m / s wall velocity) for 12 hours. Figure 5a and 5b SEM images of the product obtained after this mechanical consolidation are shown at two different magnifications. In these images, it is seen that the ZrO2 microspheres partially coat thin layers of graphite. It is also apparent that the diameter of the graphite spheroids (product particles) is slightly smaller than that of the ZrO2 microspheres.

[0135] The graphite spheroid product particles were then separated from the ZrO2 microspheres using density with methylene iodide (Ml-GEE, GEO Liquids, Inc., Prospect Heights, IL, USA), which has a density of 3.32 g / cm3 3 (between 5.68 g / cm3 3 for ZrO2 and 2.23 g / cm3 3 for graphite). Figure 6a and 6b SEM images of the graphite spheroid product particles after separation with methylene iodide and drying are shown at two different magnifications. Almost all of the ZrO2 was removed, so that the majority of the remaining particles are graphite spheroids.

[0136] XRD patterns of the graphite were obtained before and after the mechanical consolidation process. Based on the obtained XRD patterns, it appears that the mechanical consolidation process slightly damaged the crystal structure of the graphite and caused some loss of crystallinity. This is evidenced by the broadened peaks and amorphous character in the XRD patterns. The patterns also indicate that a small amount of ZrO2 impurity remained in the sample. (It is expected that such impurities can be easily removed using better separation techniques on an industrial scale.) Thus, the graphite sphere product particles were recrystallized by annealing (heating) in argon at 3000 °C for three hours. Subsequently, an XRD pattern of the annealed product particles was obtained. Now all of the peaks are sharp, indicating good crystallinity. For the annealed product particles, the d-spacing was determined based on the position of the (002) x-ray diffraction peak to be 002 The d-spacing is indicating a high degree of graphitization. There is now a small amount of ZrC in the XRD pattern, presumably due to the carbon reduction of ZrO2 at high temperature in argon. Figure 7a 、 7b and 7c show these different XRD patterns, i.e., the graphite flake precursor particles before mechanical consolidation, the graphite sphere product particles after mechanical consolidation and separation from the template medium, and the graphite sphere product particles after annealing.

[0137] Figure 8 shows the particle size distribution of the graphite sphere product particles after annealing. For comparison, the particle size distribution of the ZrO2 template medium is also shown (dashed line). It is seen that the graphite sphere product particles are very uniform in size, with an average diameter of about 41 μm.

[0138] An electrode was prepared using these graphite sphere product particles as anode active material, and a lithium half-cell unit was prepared and tested containing this electrode. The cell was cycled between 0.005 V and 0.9 V. For the first cycle, the cell was cycled at C / 10 and at a lower potential limit, the cell was held at a constant potential until the current decreased to a value of C / 20, and then the next cycle was started. For each of the subsequent cycles, the cell was cycled at C / 5 and held at each lower potential limit until the current decreased to C / 10, and then the next cycle was started. Figure 9a 、 9b and 9c show the electrochemical performance of this cell. In these figures, the voltage profile, the corresponding differential capacity profile, and the cycling performance are shown, respectively. The voltage profile is typical for graphite, while the expected staging is clearly observed in the differential capacity profile. A reversible capacity of about 275 mAh / g was obtained, with good cycling performance.

[0139] To further analyze the structure of these graphite sphere product particles, cross sections of representative particles were taken and images were acquired using SEM, as described in detail above. Figure 10a , 10b and 10c show several of the SEM images obtained. Figure 10a show the complete cross section of a product particle, while Figure 10b and 10c show different parts of the product particle at greater magnification. Some product particles contain void space near the center of the particle (i.e., a hollow core). In addition, voids arranged in concentric layers are observed throughout the particle. Thus, the product particles appear to have a novel concentric structure. The product particles contain concentric layers of graphene sheets. Figure 10d show the cross section of a product particle, with its perimeter and centroid shown. Figure 10e show a plot of the residuals of the interpolated radial segment values versus the interpolated f(x) values as a function of x for the product particle. From this data, the roughness is determined. The graphite product particles are smooth, with a roughness of only 0.0052, and no cavities.

[0140] Inventive Example 2 - Micro-Granulation of Lithium Transition Metal Oxide Powders

[0141] Sub-micron irregularly shaped precursor NMC particles were aggregated into larger regularly shaped NMC product particles using zirconium oxide (Zr02) microspheres as a templating medium, similar to the previous example.

[0142] The NMC precursor particles were prepared using a full solid state method, with the chemical formula LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 02. Specifically, stoichiometric amounts of NiO (Sigma Aldrich, 99%), MnO (Aldrich, 99%), Co304 (Alfa Aesar, 99.7%), and Li2C03 (Alfa Aesar, 99) were mixed together with a 10% excess of Li2C03 using a SPEX 8000 mixer by high energy ball milling. Approximately 2.4 g sample sizes were milled with 180 g of 1.6 mm stainless steel balls (Thomson Linear Motion) for 4 hours. The resulting ball-milled mixture was then pelletized and heated in air at 900 °C for 3 hours. Finally, the resulting pellets were ground into a fine powder to produce the NMC precursor particles. Figure 11a and 11b SEM images of these NMC precursor particles are shown at two different magnifications. Irregular agglomeration of sub-micron NMC particles can be observed.

[0143] As described above, a mixture comprising approximately 225 g of Zr02microspheres template medium and approximately 15 g of NMC precursor particles (approximately 50 mL total powder volume) was prepared and then subjected to mechanical consolidation. The system was run at 1000 rpm (approximately 8 m / s wall velocity) for 24 hours. Figure 12a and 12b SEM images of the product obtained after this mechanical consolidation are shown at two different magnifications. In these images, it is seen that the Zr02microspheres partially coat the NMC in a thin layer. It is also apparent that the size of the NMC tetrahedra (product particles) is slightly smaller than the Zr02microspheres, but much larger than the NMC precursor particles.

[0144] The NMC tetrahedral product particles were then separated from the Zr02microspheres using a 400 mesh sieve. Figure 13a and 13b SEM images of the tetrahedral shaped NMC product particles after separation in this manner are shown at two different magnifications. The product particles are smooth. Also, almost all of the Zr02is removed.

[0145] XRD patterns of the NMC product particles were obtained before and after the mechanical consolidation process. Again, it appears that the mechanical consolidation process slightly damaged the crystal structure of the product particles and caused some loss of crystallinity. This is evidenced by the broadened peaks and amorphous character in the XRD patterns. The patterns also indicate that a small amount of Zr02impurity remains in the sample. (Again, it is expected that such impurities can be easily removed using better separation techniques on an industrial scale.) The NMC product particles were then recrystallized by annealing in air at 900 °C. The XRD pattern of the annealed product particles was subsequently obtained, and now all of the peaks are sharp, indicating good crystallinity. A small amount of Zr02remains in the XRD pattern. Figure 14a , 14b and 14c show these different XRD patterns, namely the NMC precursor particles before mechanical consolidation, the tetrahedral shaped NMC product particles after mechanical consolidation and separation from the template medium, and the NMC product particles after annealing, respectively.

[0146] Figure 15 The particle size distribution of the NMC product particles after annealing is shown. For comparison, the particle size distribution of the Zr02template medium is also shown (dashed line). It is seen that the NMC product particles are very uniform in size, with an average size (D50) of approximately 28 μm and a narrow distribution, (D90-D10) / D50 = 0.66.

[0147] Electrodes were prepared using these NMC product particles as the cathode active material, and lithium half-battery cells containing such electrodes were prepared and tested. For the first cycle, the battery cells were cycled between 3.0 V and 4.2 V at C / 10. For the remaining cycles, the battery cells were cycled at C / 4 and held at the upper cutoff potential until the current dropped to C / 10, then the next cycle was performed. Figure 16a and 16b The electrochemical performance of this battery cell is shown. In these figures, the voltage profile and cycling performance are shown, respectively. The voltage profile is typical for NMC, and a reversible capacity of about 90 mAh / g was obtained.

[0148] To further analyze the structure of these NMC product particles, cross sections of representative particles were taken and images were acquired using SEM, as described previously. Figure 17a 、 17b , 17c and 17d show several of the images obtained in the SEM images. Figure 17a The complete cross section of a product particle is shown, while Figure 17b 、 17c and 17d show different parts of the product particle at several larger magnifications. The product particles are smooth, and it is seen that the shape is a tetrahedron with rounded corners. They contain a core of randomly oriented crystallites with an average size of about 1 μιη, and are coated with smaller randomly oriented crystallites with an average size of about 0.3 μιη. Thus, the aggregated NMC product particles appear to be characterized by a novel structure.

[0149] Figure 17e The cross section of a product particle is shown, where its perimeter and centroid are shown. Figure 17f A plot of the residuals of the interpolated radial segment values versus the interpolated f(x) values as a function of x for the product particle is shown. From this data, the roughness is determined. The NMC graphite product particles are smooth, with a roughness of only 0.0094, and no cavities.

[0150] Comparative Example - Attempt to Micro-Granulate Lithium Transition Metal Oxide with an Auto-Milling Process

[0151] Zirconium oxide (Zr02) microspheres and NMC precursor particles similar to the previous example were used. A mixture containing the same ratio of Zr02and NMC was mixed in a Brinkmann Retsch automatic mill. The automatic mill was set to run at about 120 rpm for two weeks. Figure 18a and 18bSEM images obtained for this sample that was subjected to automated milling are shown. The SEM images show that all of the Zr02microspheres are loosely coated with NMC, but little to no granulation of the NMC is observed. This comparative example demonstrates that very long automated milling times do not provide the unique benefits of the mechanical consolidation process.

[0152] Inventive Example 3 - Micro-Granulation of a Mixture of Precursor Particles with Different Compositions and Different Average Crystallite Sizes.

[0153] Several types of precursor particles having different compositions and average crystallite sizes were aggregated using zirconia (Zr02) microspheres as the templating medium, similar to the previous example.

[0154] A mixture was prepared containing approximately 180 g of Zr02microsphere templating medium, 6.94 g of NiO (Sigma Aldrich, 99%), 2.20 g of MnO (Aldrich, 99%), 2.48 g of Co304(Aldrich, 99.7%), and 6.29 g of Li2C03(Aldrich, 99%). The average crystallite size of the Co304was 0.3 μm and the average crystallite size of the NiO was 2 μm as determined by SEM observation of single crystalline microspheres. The mixture was then subjected to mechanical consolidation at 1000 rpm (approximately 8 m / s wall velocity) for 18 hours as described above. The product particles were then separated from the Zr02microspheres using a 400 mesh sieve. Figure 20a and 20b SEM images of the cross-section of the product particles are shown at two different magnifications. The product particles are smooth, with most of the particles having a diameter of 5-10 μm. In cross-section, the particles can be seen to have a core-shell structure. The brightness of the particle core and the particle shell are different, indicating that the elemental composition of the core and the shell are different. Figure 21 A cross-sectional image of the particle is shown, with the locations of five data points indicated as spectra 1-5. The elemental composition at each point, as determined by EDS, is listed in Table 1 below. The core is rich in Co, while the shell is rich in Mn and Ni.

[0155] Table 1.

[0156]

[0157] Inventive Example 4 - Synthesis of O3 Phase LiNi x Mn y Co z O 2 Powder, where x + y + z = 1 and comprising particles with a Ni content in the core higher than the Ni content in the shell Figure 22

[0158] LiNi 1 / 3 Mn 1 / 3 Co 1 / 3The target composition of O2 (NMC111) is used as a Mn-rich particle shell. The shell precursor powder was prepared as follows: 12.88 g of NiO (Sigma-Aldrich, 99%), 12.24 g of MnO (Aldrich, 99%), 13.85 g of Co3O4 (Alfaea, 99.7%), and 21.03 g of Li2CO3 (Alfaea, 99%) were used; according to formula LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2 (corresponding to 10% excess Li2CO3) and 10 kg of 0.5-inch stainless steel balls were sealed in a 5L stainless steel can mill (US Stoneware) and milled at 85 rpm for one week. The XRD pattern of the resulting shell precursor powder was obtained in... Figure 23 It is shown in the figure. It contains a mixture of Li2CO3, Co3O4, NiO, and MnO phases. SEM images of the resulting shell precursor powder are shown in [the figure]. Figure 24 As shown in the figure, it contains microcrystals with a size of less than 0.1 μm.

[0159] Choose LiNi 0.6 Mn 0.2 Co 0.2 The target composition of O2 (NMC622) was used as a Ni-rich particle core. The core precursor powder was prepared as follows: 41.61 g of NiO (Sigma-Aldrich, 99%), 13.18 g of MnO (Aldrich, 99%), 14.90 g of Co3O4 (Alfaea, 99.7%), and 10 kg of 0.5-inch stainless steel balls were sealed in air in a 5L stainless steel can mill (US Stoneware) and milled at 85 rpm for one week (labeled as Intermediate A). Figure 25 The XRD pattern of intermediate A is shown, corresponding to a single-phase rock salt structure. The SEM image of intermediate A is shown in... Figure 26 As shown in the figure. Intermediate A consists of microcrystals with a size of less than 0.1 μm. 15 g of intermediate A was mixed with 7.83 g of Li₂CO₃ (Alfa Esa, 99%; according to formula LiNi) using a mortar and pestle. 0.6 Mn 0.2 Co 0.2 O2 (corresponding to 5% excess Li2CO3) is mixed until a homogeneous mixture is obtained (approximately 10 minutes). The mixture is placed in an alumina crucible and heated in air at 900°C in a box furnace for 3 hours to obtain core precursor particles. The purpose of this heating step is to increase the crystallite size of the core precursor particles so that they are more than 10% larger than the crystallite size of the shell precursor particles. Figure 27 SEM images of the obtained core precursor particles are shown. They have an average crystallite size of approximately 2 μm. Figure 28aAn XRD pattern of the core precursor particles is shown, corresponding to the pure phase O3 phase NMC622.

[0160] A mixture comprising approximately 180 g of Zr02microspheres template medium, 13.33 g of shell precursor particles and 6.67 g of core precursor particles was prepared. The mixture was then subjected to mechanical fusion at 1000 rpm (approximately 8 m / s wall velocity) for 20 hours as described above. The product particles were then separated from the Zr02microspheres using a 400 mesh sieve.

[0161] Figure 29 and 28b SEM images of cross-sections of the product particles are shown at two different magnifications. Most of the product particles have a diameter of 5-20 μm. In cross-section, the particles can be seen to have a core-shell structure. The brightness of the particle core and particle shell is different, indicating that the elemental composition of the core and shell is different. The core is composed of randomly oriented crystallites having the same average crystallite size as the core precursor particles, while the shell is composed of randomly oriented crystallites having the same average crystallite size as the shell precursor particles. Both the core and the shell contain pores. Figure 30a A cross-section SEM image of a product particle is shown, with the locations of five data points shown, labeled Spectrum 1-5. The elemental composition at each point, as determined by EDS, is listed in Table 2 below. The Ni content of the core is approximately 13% greater than the shell.

[0162] Table 2.

[0163]

[0164] Figure 30b A cross-section image of a product particle is shown, with the locations of five data points shown, labeled Spectrum 1-5. The elemental composition at each point, as determined by EDS, is listed in Table 2 below. The Ni content of the core is approximately 13% greater than the shell. Figure 31 An EDS Ni mapping of the same product particle is shown. The intensity of the Ni signal from the core is stronger than the signal from the shell, demonstrating that the core of the product particle is rich in Ni, while the shell is rich in Co and Mn. Figure 32 An XRD pattern of the product particles is shown. This XRD pattern corresponds to the XRD pattern of a mixture of the product particles and the core particles.

[0165] The product particles were placed in an alumina crucible and heated in air at 900 °C for 3 hours in a box furnace to cause the components of the product particles to react to form a layered lithium nickel manganese cobalt oxide having the overall composition LiNi 0.4 Mn 0.3 Co 0.3 O2. Figure 33 An XRD pattern of the heated product particles is shown. This XRD pattern contains peaks corresponding only to the O3 phase of LiNi x Mn y Co z O2, where x+y+z = 1.Figure 34 An SEM image of the heated product particles is shown. The size of the heated product particles is the same as the size of the product particles before heating. The heated product particles contain randomly oriented crystallites that are also randomly shaped and have an average size of 2 μm. Some of the heated product particles contain voids, while others do not.

[0166] Figure 35 A cross-sectional image of the heated product particles is shown, with the locations of six data points shown, labeled as spectra 1-6. The elemental composition at each point, as determined by EDS, is listed in Table 3 below. Diffusion of the transition metals during the high temperature heating process resulted in a concentration gradient, with the Ni content increasing gradually from the shell to the core, and the Mn content increasing gradually from the core to the shell. Figure 34 The variation of the transition metal composition with distance from the surface of the heated product particles is shown, as determined by spectra 1 through 6 in Inventive Example 5 - Micro-Granulation of Graphite Flakes The Ni concentration near the core is about 9% higher than the Ni concentration in the shell.

[0167] Table 3.

[0168]

[0169] Figure 36

[0170] Graphite product particles were prepared using the same method as in Inventive Example 1, except that after the mechanical consolidation process, the product particles were separated from the ZrO2 template medium by passing the product particle / template medium mixture through a 38 μm sieve. The product particles were then heated under argon to 2840°C for 90 minutes, producing graphite spheres. The annealed product particle spheres had the same shape and average particle size as those of Inventive Example 1, but had fewer voids, presumably because diiodomethane was not used during the process. It is believed that diiodomethane can intercalate between the graphite layers during heating, creating concentric voids and interstitial spaces. Inventive Example 6 - Micro-Granulation of Petroleum Coke An SEM cross-sectional image of some of the annealed product particles of Inventive Example 5 is shown. Some of the annealed product particles contain very few voids or no voids, some contain concentric voids, and some contain a central interstitial space. All of the annealed product particles contain graphite layers arranged concentrically in nested ovoid or spherical shells, with the basal plane edges of the graphite layers not extending outward from the center point to the outside of the particle.

[0171] ​

[0172] A mixture of 30 g of petroleum coke and 330 g of ZrO2spheres of the same type as used in Invention Example 1, the petroleum coke being in the form of plates having an average plate thickness of 2 μm and an average plate width of 10 μm, was subjected to a high shear and high pressure field for 32 hours as described in Example 1. The resulting product particles were separated from the ZrO2spheres using a 400 mesh sieve. The resulting product particles had a nodular shape, but were rounded and smooth, and had an average diameter of 20 μm.

[0173] The foregoing examples demonstrate that mechanical fusion can be used to simply and effectively aggregate various precursor particles into larger product particles. The product particles are uniform, and can desirably be smooth and have a spherical or rounded shape. In some cases, the method can produce particles having novel structures. Also, as demonstrated in laboratory test cells, the present invention can be used to make particles suitable for electrode materials in lithium batteries.

[0174] All of the above U.S. patents, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification are incorporated herein by reference in their entirety.

[0175] While particular elements, embodiments, and applications of the present invention have been shown and described, it will be understood, of course, that, in the interest of brevity, many details of the application have been omitted and, accordingly, modifications can be made in the details within the scope and range of equivalents of the claims. For example, it is contemplated that other methods capable of providing shear and pressure field conditions similar to those provided by mechanical fusion can also provide similar uniform product particles. Such modifications are therefore intended to be included within the scope of the claims.

[0176] Also provided herein are the following items:

[0177] 1. A method of micro-pelletization of precursor particles, the method comprising:

[0178] obtaining a quantity of precursor particles having an average particle size of less than 1000 μm;

[0179] obtaining a quantity of template media having an average particle size of less than 500 μm and a hardness greater than the precursor particles;

[0180] preparing a mixture comprising the quantity of precursor particles and the quantity of template media; and

[0181] subjecting the mixture to a high shear and high pressure field, thereby aggregating the precursor particles into product particles.

[0182] 2. The method of item 1, wherein the step of subjecting the mixture to a high shear and high pressure field comprises mechanically fusing the mixture.

[0183] 3. The method of item 1, wherein the average size of the precursor particles is less than 50 μιη.

[0184] 4. The method of item 3, wherein the average size of the precursor particles is less than 10 μιη.

[0185] 5. The method of item 1, wherein the precursor particles are a powder for a battery electrode, a fertilizer, a pharmaceutical, a toner, a pigment, a filler, or a catalyst.

[0186] 6. The method of item 5, wherein the precursor particles are a carbonaceous powder or a mixed metal oxide powder, or a metal carbonate powder.

[0187] 7. The method of item 6, wherein the precursor particles comprise carbon.

[0188] 8. The method of item 6, wherein the precursor particles are graphite sheets or LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2 powders.

[0189] 9. The method of item 6, wherein the precursor particles are a mixed metal oxide powder, and the step of obtaining the quantity of precursor particles comprises:

[0190] obtaining a metal oxide raw material powder; and

[0191] ball-milling the metal oxide raw material powder to produce the precursor particles.

[0192] 10. The method of item 1, comprising ball-milling at least a portion of the quantity of precursor particles prior to preparing the mixture.

[0193] 11. The method of item 1, comprising heating at least a portion of the quantity of precursor particles prior to preparing the mixture.

[0194] 12. The method of item 1, wherein the precursor particles are irregularly shaped powders.

[0195] 13. The method of item 1, wherein the average size of the template medium is 100 μιη or less.

[0196] 14. The method of item 1, wherein the template medium is selected from the group consisting of zirconia, tungsten carbide, tungsten, silica, alumina, silicon nitride, hardened steel, stainless steel, and agate.

[0197] 15. The method of item 1, wherein the surface of the template media is smooth.

[0198] 16. The method of item 15, wherein the template media is spherical in shape.

[0199] 17. The method of item 1, wherein the size distribution of the template media is uniform such that (D90-D10) / D50 < 2.

[0200] 18. The method of item 1, wherein the bulk volume of the amount of template media is greater than the bulk volume of the amount of precursor particles.

[0201] 19. The method of item 1, wherein the bulk volume of the amount of template media is greater than 10% of the bulk volume of the amount of precursor particles.

[0202] 20. The method of item 19, wherein the bulk volume of the amount of template media is greater than the bulk volume of the amount of precursor particles or about three times the bulk volume of the amount of precursor particles.

[0203] 21. The method of item 2, wherein the mechanical fusion is performed in a mechanical fusion system comprising a chamber, a rotating wall within the chamber, a scraper within the rotating wall, and a ram within the rotating wall.

[0204] 22. The method of item 21, wherein the mechanical fusion comprises:

[0205] setting a gap of about 0.5 mm between the scraper and the rotating wall;

[0206] setting a gap of about 1.4 mm between the ram and the rotating wall; and

[0207] performing rotation such that the wall surface velocity is about 8 m / s or greater.

[0208] 23. The method of item 1, wherein the average size of the product particles is between 10 μm and 100 μm.

[0209] 24. The method of item 1, wherein the size distribution of the product particles is uniform such that (D90-D10) / D50 < 2.

[0210] 25. The method of item 2, wherein the surface of the product particles is smooth.

[0211] 26. The method of item 2, wherein the surface of the product particles is free of cavities.

[0212] 27. The method of item 2, wherein the product particles have a roughness of less than 0.02.

[0213] 28. The method of item 25, wherein the product particles are spheroid in shape.

[0214] 29. The method of item 25, wherein the product particles are tetrahedron in shape.

[0215] 30. The method of item 2, further comprising: annealing the product particles at an elevated temperature.

[0216] 31. Use of product particles prepared according to the method of item 1 in a battery electrode, a fertilizer, a pharmaceutical, a toner, a pigment, a filler, or a catalyst.

[0217] 32. A rechargeable battery comprising an anode and a cathode, wherein at least one of the anode and the cathode comprises product particles prepared according to the method of item 1.

[0218] 33. A graphite particle comprising graphite particles, wherein:

[0219] the graphite particles are shaped as spheroids or ovoids;

[0220] the graphite particles comprise concentric nested spheroids or ovoids of graphene layers;

[0221] the graphene layers are randomly positioned on the surface of the concentric nested spheroids or ovoids, except that the graphene layers are oriented such that their basal planes are tangential to the concentric nested spheroids or ovoids;

[0222] the graphite particles have an average particle size of greater than 2 pm; and

[0223] the graphite particles have an average d spacing of less than 002 .

[0224] 34. The graphite particle of item 33, wherein the graphite particles comprise concentric layers of porosity and a hollow core.

[0225] 35. The graphite particle of item 33, wherein the graphite particles have an average particle size of between 5 pm and 50 pm and a size distribution of (D90-D10) / D50 < 2.

[0226] 36. An aggregated graphite particle comprising an aggregate of graphite particles prepared according to the method of item 1, wherein the precursor particles are the graphite particles and the product particles are the graphite particles.

[0227] 37. A lithium-mixed metal oxide particle comprising particles having a core of lithium nickel manganese cobalt oxide crystallites randomly oriented and having an average size of about 1 pm, and coated with smaller randomly oriented lithium nickel manganese cobalt oxide crystallites having an average size of about 0.3 pm.

[0228] 38. A lithium nickel manganese cobalt oxide particle comprising an aggregate of lithium nickel manganese cobalt oxide particles prepared according to the method of item 1, wherein the precursor particles are lithium nickel manganese cobalt oxide particles and the product particles are the lithium nickel manganese cobalt oxide particles.

[0229] 39. The method of item 1, wherein the amount of precursor particles comprises a mixture of first particles having a first composition and second particles having a second composition, wherein the first composition and the second composition are different.

[0230] 40. The method of item 39, wherein the average crystallite size of the first precursor particles differs from the average crystallite size of the second precursor particles by at least 10%.

[0231] 41. A lithium transition metal oxide particle comprising particles of lithium transition metal oxide, wherein:

[0232] the particles comprise at least two transition metals selected from the group consisting of Mn, Ni, and Co;

[0233] the particles have an O3 structure;

[0234] the particles have an average particle size ranging from 1 pm to 50 pm; and

[0235] the particles comprise crystallites of random shape and size throughout their interior.

[0236] 42. The lithium transition metal oxide particle of item 41, wherein the crystallites have an average size greater than 0.5 pm and the average particle size of the particles is more than 5 times greater than the average crystallite size.

[0237] 43. The lithium transition metal oxide particle of item 41, wherein the composition of one of the at least two transition metals changes by at least 5 atomic percent from the core of the particles to the shell of the particles.

[0238] 44. A lithium transition metal oxide particle comprising lithium transition metal oxide particles prepared according to the method of item 1, wherein the precursor particles are lithium transition metal oxide particles and the product particles are the lithium transition metal oxide particles.

[0239] 45. The method of item 1, comprising separating the product particles from the template medium after the aggregation of the precursor particles into the product particles.

Claims

1. A method of aggregating precursor particles by micro-pelletization, the method comprising: obtaining a quantity of precursor particles having an average particle size of less than 1000 μm; obtaining a quantity of template media having an average particle size of less than 500 μm and a hardness greater than the precursor particles; preparing a mixture comprising the quantity of precursor particles and the quantity of template media; subjecting the mixture to dry mechanical fusion to aggregate the precursor particles into product particles, wherein the dry mechanical fusion is performed in a mechanical fusion system comprising a chamber, a rotating wall within the chamber, a scraper within the rotating wall, and a pressure head within the rotating wall, and the dry mechanical fusion comprises: performing rotation such that the mixture passes through a gap between the pressure head and the rotating wall, and a surface velocity of the rotating wall is 8 m / s or greater; and after aggregating the precursor particles into the product particles, separating the product particles from the template media. The average particle size of the precursor particles is less than 50 μm.

2. The method of claim 1, wherein, The average particle size of the precursor particles is less than 10 μm.

3. The method of claim 2, wherein, The precursor particles are powders for battery electrodes, fertilizers, pharmaceuticals, toners, pigments, fillers, or catalysts.

4. The method of claim 1, wherein, The precursor particles are carbonaceous powders or mixed metal oxide powders, or metal carbonate powders.

5. The method of claim 4, wherein, The precursor particles comprise carbon.

6. The method of claim 5, wherein, The precursor particles are mixed metal oxide powders, and the step of obtaining a quantity of precursor particles comprises:

7. The method of claim 5, wherein, The precursor particles are graphite sheets or LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2 powder.

8. The method of claim 5, wherein, obtaining a metal oxide raw material powder; and ball-milling the metal oxide raw material powder to produce the precursor particles.

9. The method of claim 1, comprising ball-milling at least a portion of the quantity of precursor particles prior to preparing the mixture.

10. The method of claim 1, comprising heating at least a portion of the quantity of precursor particles prior to preparing the mixture. The precursor particles are powders having irregular shapes.

11. The method of claim 1, wherein, The average particle size of the template media is 100 μm or less.

12. The method of claim 1, wherein, The template media is selected from the group consisting of zirconia, tungsten carbide, tungsten, silica, alumina, silicon nitride, hardened steel, stainless steel, and agate.

13. The method of claim 1, wherein, The surface of the template media is smooth.

14. The method of claim 1, wherein, The template media is spherically shaped.

15. The method of claim 14, wherein, The size distribution of the template media is uniform such that (D90-D10) / D50 < 2.

16. The method of claim 1, wherein, The bulk volume of the quantity of template media is greater than the bulk volume of the quantity of precursor particles.

17. The method of claim 1, wherein, The bulk volume of the quantity of template media is greater than 10% of the bulk volume of the quantity of precursor particles.

18. The method of claim 1, wherein, The bulk volume of the quantity of template media is greater than the bulk volume of the quantity of precursor particles or three times the bulk volume of the quantity of precursor particles.

19. The method of claim 18, wherein, The dry mechanical fusion further comprises:

20. The method of claim 1, wherein, setting a gap of 0.5 mm between the scraper and the rotating wall; and setting a gap of 1.4 mm between the pressure head and the rotating wall. The average particle size of the product particles is between 10 μm and 100 μm.

21. The method of claim 1, wherein, ​ 22. The method of claim 1, wherein, The size distribution of the product particles is uniform such that (D90-D10) / D50 < 2.

23. The method of claim 1, wherein, The surface of the product particles is smooth.

24. The method of claim 1, wherein, The surface of the product particles is free of cavities.

25. The method of claim 1, wherein, The product particles have a roughness of less than 0.

02.

26. The method of claim 23, wherein, The product particles are spherical in shape.

27. The method of claim 23, wherein, The product particles are tetrahedral in shape.

28. The method of claim 1, further comprising: The product particles are annealed at an elevated temperature.

29. The method of claim 1, wherein, The amount of precursor particles comprises a mixture of first particles having a first composition and second particles having a second composition, wherein the first composition and the second composition are different.

30. The method of claim 29, wherein, The average crystallite size of the first particles differs from the average crystallite size of the second particles by at least 10%. The product particles are annealed at an elevated temperature.

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