Iron phosphate synthesis and composition for reducing waste

Abstract

Methods for preparing iron phosphate and electrode films for energy storage devices that do not contain solid or liquid waste are described herein. Compositions containing iron phosphate prepared by the methods disclosed herein are also described.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] For example, any application filed with this application, such as U.S. Provisional Application No. 63 / 527,272, filed on July 17, 2023, and incorporated herein by reference in its entirety, in which a foreign or domestic priority claim is identified in the application data sheet or petition, is incorporated herein by reference under 37 CFR 1.57, as well as Rules 4.18 and 20.6.

[0002] The present disclosure generally relates to energy storage devices, and more particularly to methods for preparing energy storage device active materials, active material precursors, and compositions containing them.

Background Art

[0003] Lithium - ion batteries are desirable due to optimized cost, safety, lifespan, and moderate energy density. Current cathode manufacturing methods require numerous steps and can generate a significant amount of waste. For example, some conventional cathode material manufacturing methods for iron phosphate, which is a precursor of lithium iron phosphate active material, require multiple chemical steps that produce waste that is not easily recycled or disposed of. Therefore, new methods for manufacturing active material precursors and / or active materials can help reduce the end - use cost of energy storage devices (e.g., lithium - ion batteries).

Summary of the Invention

Problems to be Solved by the Invention

[0004] For the purpose of summarizing the advantages achieved beyond this disclosure and the prior art, certain purposes and advantages of this disclosure are described herein. Not all such purposes or advantages can be achieved in any particular embodiment. Therefore, for example, a person skilled in the art will recognize that the present invention may be embodied or implemented to achieve or optimize one or more advantages as taught herein, without necessarily achieving other purposes or advantages as taught or suggested herein.

[0005] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of preferred embodiments with reference to the accompanying drawings, and the invention is not limited to any particular preferred embodiment disclosed. [Means for solving the problem]

[0006] One embodiment describes a method for preparing iron phosphate. This method includes the steps of combining an iron-based substance, phosphoric acid, and a liquid to form a reaction reaction containing iron phosphate, wherein the molar ratio of the iron-based substance to the phosphoric acid is about 1:1.5 to 1.5:1, and treating the reaction reaction to form a composition containing iron phosphate.

[0007] In some embodiments, the iron-based material contains iron metal. In some embodiments, the iron-based material contains at least 95% iron. In some embodiments, the iron-based material contains D particles of about 1 μm to 500 μm. 50 It contains iron-based powder particles with a particle size distribution. In some embodiments, the iron-based powder particles include spherical morphology. In some embodiments, the iron-based material includes iron scrap metal.

[0008] In some embodiments, the combining step includes adding the iron-based substance to the solution containing the liquid and the iron-based substance at a rate of about 0.1 g / min to about 1,000 g / min. In some embodiments, the combining step includes adding the phosphoric acid to the solution containing the liquid and the iron-based substance at a rate of about 0.1 g / min to about 1,000 g / min. In some embodiments, the processing step of the reaction mixture includes heating the reaction mixture to a temperature in the range of about 500°C to 1000°C. In some embodiments, the processing step of the reaction mixture includes at least one of drying, calcination, and crushing.

[0009] In some embodiments, the composition contains at least 33 wt.% iron and at least 18 wt.% phosphorus. In some embodiments, the composition contains at least 38 wt.% iron and at least 22 wt.% phosphorus. In some embodiments, the total impurities in the composition are less than 1 wt.%. In some embodiments, the composition contains less than 0.01 wt.% magnesium. In some embodiments, the liquid contains water. In some embodiments, the reaction mixture contains at least about 20 wt.% of the liquid. In some embodiments, the molar ratio of iron-based substance to phosphoric acid is about 1:1.25 to 1.25:1. In some embodiments, the method further includes recovering by-products. In some embodiments, the by-products include substances selected from the group consisting of H2, water, and combinations thereof.

[0010] Another embodiment describes a method for preparing lithium iron phosphate. This method includes the steps of forming a composition comprising iron phosphate according to a method disclosed herein, combining the composition with a lithium source and a carbon source to form a calcined mixture, and calcining the calcined mixture to form lithium iron phosphate. In some embodiments, the combining step includes combining with a liquid to form a calcined mixture. In some embodiments, the method further includes spray-drying the calcined mixture. In some embodiments, the method further includes grinding the calcined mixture.

[0011] Another embodiment describes a method for preparing an electrode film for an energy storage device. This method includes the steps of forming lithium iron phosphate according to a method disclosed herein, combining a binder with lithium iron phosphate to form an electrode film mixture, and processing the electrode film mixture to form an electrode film.

[0012] In some embodiments, the step of combining the binder with lithium iron phosphate includes combining the binder and conductive carbon with lithium iron phosphate. [Brief explanation of the drawing]

[0013] [Figure 1] This is a flowchart of an exemplary prior art method for preparing iron phosphate.

[0014] [Figure 2] This is a flowchart of a method for preparing iron phosphate according to one embodiment.

[0015] [Figure 3] This is a flowchart of a method for preparing iron phosphate according to one embodiment.

[0016] [Figure 4] This is a flowchart of two methods for preparing iron phosphate, according to several embodiments.

[0017] [Figure 5A] This is an image of powder particles of a spherical iron-based material according to one embodiment.

[0018] [Figure 5B] Images of powder particles of iron-based material having an undefined form according to several embodiments. [Figure 5C] Images of powder particles of iron-based material having an undefined form according to several embodiments.

[0019] [Figure 6] A flowchart of a method for preparing lithium iron phosphate according to one embodiment.

[0020] [Figure 7A] An image of reactants for forming FePO4 during a stirring reaction according to one embodiment.

[0021] [Figure 7B] An image of the paste formed at the end of the reaction according to one embodiment.

[0022] [Figure 7C] An image of the naturally dried and granulated paste according to one embodiment.

[0023] [Figure 7D] An image of the particles after firing according to one embodiment.

[0024] [Figure 7E] An XRD pattern of an iron phosphate composition prepared by a method according to one embodiment, compared to commercially available iron phosphate. <(

[0025] [Figure 8A] An XRD pattern of an iron phosphate composition prepared by a method according to one embodiment, compared to a standard.

[0026] [Figure 8B] An XRD pattern of commercially available iron phosphate, compared to a standard.

[0027] [Figure 9A] An XRD pattern of a lithium iron phosphate composition prepared by a method according to one embodiment, compared to a standard.

[0028] [Figure 9B] An XRD pattern of commercially available lithium iron phosphate, compared to a standard.

[0029] [Figure 10] This graph shows the specific charge capacity and specific discharge capacity of a coin-type cell containing lithium iron phosphate prepared by a method according to one embodiment.

[0030] [Figure 11A] This is an image of the reactants used to form FePO4 during a stirring reaction according to one embodiment.

[0031] [Figure 11B] This is an image of the paste formed after the reaction is complete, according to one embodiment.

[0032] [Figure 11C] This is an image of dried and granulated FePO4 hydrate particles according to one embodiment.

[0033] [Figure 11D] This is an image of FePO4 particles after firing.

[0034] [Figure 12A] This is an SEM image of calcined FePO4 particles according to one embodiment.

[0035] [Figure 12B] This is an XRD pattern of FePO4 calcined particles according to one embodiment.

[0036] [Figure 13A] This is an image of the product after the reaction is complete, according to one embodiment. [Figure 13B] This is an image of the product after the reaction is complete, according to one embodiment.

[0037] [Figure 13C] This is an image of particles fired in a rotary furnace according to one embodiment.

[0038] [Figure 13D]This is an image of anhydrous FePO4 particles collected after calcination according to one embodiment.

[0039] [Figure 14] This is an XRD pattern of calcined FePO4 particles according to one embodiment. [Modes for carrying out the invention]

[0040] ·Definition As used herein, the terms “battery” and “condenser” should be given their usual and customary meanings to those skilled in the art. The terms “battery” and “condenser” are non-exclusive. A condenser or battery may refer to a single electrochemical cell that may operate independently or as part of a multi-cell system.

[0041] The “self-supporting” electrode film or active layer provided herein is an electrode film or layer incorporating a binder matrix structure sufficient to support the film or layer and maintain its shape so that the electrode film or layer can be self-supporting. When incorporated into an energy storage device, the self-supporting electrode film or active layer incorporates such a binder matrix structure. Generally, depending on the method used, such an electrode film or active layer is strong enough to be used in a method of fabricating an energy storage device without the use of any external support elements such as current collectors or other films. For example, the “self-supporting” electrode film may be strong enough to be rolled (or wound), handled, and unrolled (or unwound) within an electrode fabrication method without the use of other support elements.

[0042] As provided herein, a “solvent-free” electrode film is an electrode film that does not contain any detectable processing solvent, processing solvent residue, or processing solvent impurities. Processing solvents or conventional solvents include organic solvents. Dry electrode films, such as cathode electrode films or anode electrode films, do not need to contain solvents.

[0043] A "wet" electrode or "wet process" electrode is an electrode prepared by at least one step comprising an active material, a binder, and a slurry of a processing solvent, processing solvent residue, and / or processing solvent impurities. A wet electrode may optionally contain additives.

[0044] As used herein, the terms “calcining” and “calcining” are used interchangeably and refer to heating a substance to a high temperature in the presence of an atmosphere to induce thermal decomposition, phase transition, and / or removal of volatile fractions.

[0045] ·explanation This disclosure can be understood by referring to the following detailed description. For clarity, it should be noted that certain elements of the various drawings may not be drawn to scale, may be represented schematically or conceptually, and may not otherwise precisely correspond to certain physical configurations of the embodiments.

[0046] Figure 1 shows a typical example method 100 for preparing iron phosphate. Method 100 comprises providing an iron sulfate hydrate intermediate (e.g., FeSO4·7H2O) 101. The iron sulfate hydrate intermediate is formed with hydrogen gas as a by-product 102 by dissolving iron in sulfuric acid. The iron sulfate hydrate intermediate is a raw material from other industries such as the TiO2 industry. The iron sulfate hydrate intermediate is mixed and dispersed with phosphoric acid or ammonium dihydrogen phosphate 104, then H2O2 / NaOH and / or NH3 are added to cause oxidation and precipitation 106, the mixture is filtered and washed to obtain Na2SO4 or (NH4)2SO4 and other soluble impurities 108, then the mixture is flash-dried 110, the water is drained to form iron phosphate hydrate. The iron phosphate hydrate is calcined, crushed and pulverized to form anhydrous iron phosphate 112. This method generates large amounts of Na2SO4 or (NH4)2SO4 emissions, which are water-soluble and can contaminate soil if not properly stored. Furthermore, this method may require large amounts of water to remove impurities from the resulting FePO4. In addition, this method requires high infrastructure investment, complex process control, and involves various chemicals at each step.

[0047] Methods for preparing iron phosphate and various embodiments of its composition are provided herein. The methods of the disclosure provide a simplified route for preparing iron phosphate by eliminating processing steps such as slurry preparation (including steps such as dispersion and wet grinding), oxidation, precipitation, filtration, washing, and / or drying. The methods of the disclosure can significantly reduce undesirable emissions. In some embodiments, methods for preparing iron phosphate that are free or substantially free of solid or liquid waste are disclosed. In some embodiments, by-products formed in the method for preparing iron phosphate can be recycled into the method and / or utilized. In some embodiments, the methods of the disclosure result in morphological control. In some embodiments, the methods of the disclosure can optimize lithium and carbon sources for calcination. In some embodiments, the methods of the disclosure produce hydrogen gas, a useful by-product. In some embodiments, the hydrogen gas produced in the method can be used in the process of calcining lithium iron phosphate. In some embodiments, the methods and / or systems of the disclosure can accommodate semi-solid or solid synthesis. The method disclosed herein includes forming a reaction mixture by combining an iron-based substance, phosphoric acid, and a liquid, and processing the reaction mixture to form a composition containing iron phosphate.

[0048] In some embodiments, compositions containing iron phosphate are described. In some embodiments, the compositions are 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.%, 50 wt.%, 55 wt.%, 60 wt.%, 62 wt.%, 62.1 wt.%, 62.2 wt.%, 62.3 wt.%, 62.4 wt.%, 62.5 wt.%, 62.6 wt.%, 62.7 wt.%, 62.8 wt.%, 62.9 wt.%, 63 wt.%, 63.1 wt.%, 63.2 wt.%, 63.3 wt.%, 63.4 wt.%, 63.5 wt.%, 63.6 wt.%, 63.7 wt.%, 63.8 wt.%, and 63. Contains 9 wt.%, 64 wt.%, 64.1 wt.%, 64.2 wt.%, 64.3 wt.%, 64.4 wt.%, 64.5 wt.%, 64.6 wt.%, 64.7 wt.%, 64.8 wt.%, 64.9 wt.%, 65 wt.%, 70 wt.% or 75 wt.%, 80 wt.%, 85 wt.%, 90 wt.%, 92 wt.%, 95 wt.% or 98 wt.%, 99 wt.%, 100 wt.%, or any range of values ​​in between, or about that amount, at least that amount, or at least about that amount of iron phosphate. For example, in some embodiments, the amount of iron in a composition containing iron phosphate is one of the following ranges or about that amount: 27-65 wt.%, 27-45 wt.%, 33-65 wt.%, 45-65 wt.%, 62-65 wt.%, 63-64 wt.%, 63.1-63.9 wt.%, or 62.5-64.5 wt.%.In some embodiments, the amount of phosphorus in the iron phosphate-containing composition is 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 35.1 wt.%, 35.2 wt.%, 35.3 wt.%, 35.4 wt.%, 35.5 wt.%, 35.6 wt.%, 35.7 wt.%, 35.8 wt.%, and 35.9 wt.%. , 36 wt.%, 36.1 wt.%, 36.2 wt.%, 36.3 wt.%, 36.4 wt.%, 36.5 wt.%, 37.6 wt.%, 37.7 wt.%, 37.8 wt.%, 37.9 wt.%, 38 wt.%, 40 wt.%, or 45 wt.%, or any value in between, or about that amount, at least that amount, or at least about that amount. For example, in some embodiments, the amount of phosphorus in a composition containing iron phosphate is one of the following ranges or about that amount: 15-38 wt.%, 25-38 wt.%, 15-25 wt.%, 35-37 wt.%, 36.1-36.9 wt.%, 35-36.9 wt.%, or 35.9-37.9 wt.%.

[0049] In some embodiments, the iron phosphate-containing composition contains impurities. In some embodiments, the total amount of impurities in the composition is 0.0001 wt.%, 0.0002 wt.%, 0.0003 wt.%, 0.0004 wt.%, 0.0005 wt.%, 0.0006 wt.%, 0.0007 wt.%, 0.0008 wt.%, 0.0009 wt.%, 0.001 wt.%, 0.002 wt.%, 0.003 wt.%, 0.004 wt.%, 0.005 wt.%, 0.006 wt.%, 0.007 wt.%, 0.008 wt. t.%, 0.009wt.%, 0.01wt.%, 0.011wt.%, 0.012wt.%, 0.013wt.%, 0.014wt.%, 0.015wt.%, 0.016wt.%, 0.017wt.%, 0.018wt .%, 0.019wt.%, 0.02wt.%, 0.021wt.%, 0.022wt.%, 0.023wt.%, 0.024wt.%, 0.025wt.%, 0.026wt.%, 0.027wt.%, 0.028wt. %, 0.029wt.%, 0.03wt.%, 0.031wt.%, 0.032wt.%, 0.033wt.%, 0.034wt.%, 0.035wt.%, 0.036wt.%, 0.037wt.%, 0.038wt.% , 0.039wt.%, 0.04wt.%, 0.041wt.%, 0.042wt.%, 0.043wt.%, 0.044wt.%, 0.045wt.%, 0.046wt.%, 0.047wt.%, 0.048wt.%, 0.049 wt.%, 0.05 wt.%, 0.051 wt.%, 0.052 wt.%, 0.053 wt.%, 0.054 wt.%, 0.055 wt.%, 0.056 wt.%, 0.057 wt.%, 0.058 wt.%, 0.059 wt.%, 0.06 wt.%, 0.1 wt.%, 0.5 wt.%, 1 wt.%, 1.5 wt.%, or 2 wt.%, or any range of values ​​between them, approximately that amount, maximum that amount, or maximum approximately that amount. In some embodiments, the impurities include Al, Ca, Co, Cr, Cu, K, Mg, Mn, Na, Ni, Pb, S, Si, Ti, Zn, Zr, or combinations thereof.In some embodiments, the composition is 0.0001 wt.%, 0.0002 wt.%, 0.0003 wt.%, 0.0004 wt.%, 0.0005 wt.%, 0.0006 wt.%, 0.0007 wt.%, 0.0008 wt.%, 0.0009 wt.%, 0.001 wt.%, 0.002 wt.%, 0.003 wt.%, 0.004 wt.%, 0.005 wt.%, 0.006 wt.%, 0.007 wt.%, 0.008 wt.%, 0.009 wt.%, 0.01 wt. %, 0.011wt.%, 0.012wt.%, 0.013wt.%, 0.014wt.%, 0.015wt.%, 0.016wt.%, 0.017wt.%, 0.018wt.%, 0.019wt.%, 0.02wt.%, 0.021w t.%, 0.022wt.%, 0.023wt.%, 0.024wt.%, 0.025wt.%, 0.026wt.%, 0.027wt.%, 0.028wt.%, 0.029wt.%, 0.03wt.%, 0.031wt.%, 0.03 2wt.%, 0.033wt.%, 0.034wt.%, 0.035wt.%, 0.036wt.%, 0.037wt.%, 0.038wt.%, 0.039wt.%, 0.04wt.%, 0.041wt.%, 0.042wt.%, 0 .043wt.%, 0.044wt.%, 0.045wt.%, 0.046wt.%, 0.047wt.%, 0.048wt.%, 0.049wt.%, 0.05wt.%, 0.051wt.%, 0.052wt.%, 0.053wt.% , containing 0.054 wt.%, 0.055 wt.%, 0.056 wt.%, 0.057 wt.%, 0.058 wt.%, 0.059 wt.%, 0.06 wt.%, 0.1 wt.%, 0.5 wt.%, 1 wt.%, 1.5 wt.%, or 2 wt.%, or any range of values ​​between those, approximately that amount, maximum that amount, or maximum approximately that amount of each elemental impurity (e.g., Al, Ca, Co, Cr, Cu, K, Mg, Mn, Na, Ni, Pb, S, Si, Ti, Zn, or Zr).

[0050] Method for preparing iron phosphate One aspect of the present disclosure relates to a method for preparing iron phosphate. In some embodiments, the method for preparing iron phosphate includes combining an iron-based substance, phosphoric acid, and a liquid to form a reaction mixture, and processing the reaction mixture to form a composition containing iron phosphate. In some embodiments, the reaction mixture contains iron phosphate. In some embodiments, the reaction mixture is dried immediately after it is formed. In some embodiments, only one acid is used. In some embodiments, no intermediate sulfate is formed. In some embodiments, sulfuric acid is not utilized. In some embodiments, no oxidation method is utilized.

[0051] Figure 2 is a flowchart of a method 200 for preparing iron phosphate according to one embodiment. Method 200 comprises combining an iron-based substance, phosphoric acid, and a liquid to form a reaction mixture containing iron phosphate 202. The method further comprises processing the reaction mixture to form a composition containing iron phosphate 204.

[0052] Figure 3 is a flowchart of a method 300 for preparing iron phosphate according to one embodiment. Method 300 comprises combining an iron-based substance, phosphoric acid, and a liquid to form a reaction mixture containing iron phosphate 302. The reaction mixture is dried to form a composition containing lithium iron phosphate hydrate 304. The method further comprises processing the composition to form iron phosphate 306.

[0053] Figure 4 shows flowcharts of two methods for preparing iron phosphate, namely Option 1 and Option 2. Option 1 in Figure 4 comprises combining an iron-based substance, phosphoric acid, and a liquid to form a reaction mixture 402, where most of the liquid evaporates during the exothermic reaction. The reaction mixture is then treated by calcination 404, crushing and / or grinding to form a composition containing iron phosphate. Option 2 in Figure 4 also comprises combining an iron-based substance, phosphoric acid, and a liquid to form a reaction mixture 402. The reaction mixture is then actively dried 406, calcined 404, crushed and / or ground to form a composition containing iron phosphate.

[0054] In some embodiments, the molar ratio of iron-based material to phosphoric acid is within the range of any value between 2:1, 1.9:1, 1.8:1, 1.7:1, 1.6:1, 1.5:1, 1.4:1, 1.3:1, 1.25:1, 1.2:1, 1.1:1, 1:1, 1:1.1, 1:1.2, 1:1.25, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2, or any value in between, approximately, at least, or at least approximately. For example, in some embodiments, the molar ratio of iron-based material to phosphoric acid is one of the following ranges or approximately that value: 1.4:1 to 1:1.3, 1.5:1 to 1:1.3, 1.1:1 to 1:1.1, 1:1.5 to 1.5:1, 1:1.5 to 1.2:1, 1:1 to 1.2:1, 1:1.2 to 1.1:1, or 1.2:1 to 1:2.

[0055] In some embodiments, an iron-based substance is added to phosphoric acid and a liquid to form a reaction mixture. In some embodiments, phosphoric acid and the iron-based substance are combined at a rate of 0.1 g / min, 1 g / min, 10 g / min, 100 g / min, 500 g / min, or 1,000 g / min, or any range of values ​​in between, about that value, at least that value, or at least about that value.

[0056] The iron-based material contains iron. In some embodiments, the iron-based material contains iron metal (e.g., iron scrap metal). In some embodiments, the iron-based material contains an iron powder intermediate. In some embodiments, the surface of the iron powder intermediate is modified relative to the iron-based material, for example, resulting in an improved reaction rate with the acid compared to unmodified iron powder, thereby shortening the reaction time. In other words, in some embodiments, surface modification of the iron powder intermediate promotes the reaction between the iron-based material and the acid when preparing iron phosphate. In some embodiments, the iron-based material contains an amount of iron in the range of 85 wt.%, 86 wt.%, 87 wt.%, 88 wt.%, 89 wt.%, 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, 98.5 wt.%, 99 wt.%, 99.5 wt.%, 99.8 wt.%, or 99.9 wt.%, or any range of values ​​between them, an amount about that value, at least that value, or at least about that value. For example, in some embodiments, the amount of iron in the iron-based material is one of the following ranges or approximately within that range: 90-99 wt.%, 85-95 wt.%, 95-99 wt.%, 94-96 wt.%, or 93-97 wt.%.

[0057] In some embodiments, the iron-based material is 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 23 0μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, 300μm, 310μm, 320μm, 330μm, 340μm, 350μm, 360μm, 370μm, 380μm, 390μm, 400μm, 410μm, 420μm, 430μm, 440μm, 450μm, 460μm, 470μm, 480μm, 490μm, 500μm, 510μm, 520μm, 530μm, 540μm or 550μm, or any range of values ​​between them, approximately that value, at least that value, or at least approximately that value D 50 It includes powder particles having a particle size distribution. For example, in some embodiments, the powder particles have a particle size distribution. 50 The particle size distribution is within or approximately within the following ranges: 1 μm to 500 μm, 1 μm to 100 μm, 100 μm to 200 μm, 200 μm to 300 μm, 300 μm to 400 μm, or 400 μm to 500 μm, or one of these ranges, or approximately the same. 50 Particle size represents the median of the particle size distribution where 50% of the sample volume has smaller particle sizes, i.e., D 50 The particle size divides the distribution into an upper half and a lower half.

[0058] In some embodiments, the powder particles have a spherical or substantially spherical morphology. In some embodiments, the powder particles have an amorphous morphology. In some embodiments, the powder particles have an undefined morphology. For example, Figure 5A is an image of spherical iron-based powder particles, and Figures 5B and 5C are images of iron-based powder particles having an undefined morphology.

[0059] In some embodiments, the liquid includes water, an organic solvent, a solution, or a combination thereof. In some embodiments, the liquid includes an antifoaming agent. In some embodiments, the antifoaming agent includes a silicone-based antifoaming agent, an oil-based antifoaming agent, or a combination thereof. In some embodiments, the liquid is a solution containing an organic acid dissolved in a solvent. In some embodiments, the organic acid includes oxalic acid, oxalic acid hydrate, citric acid, ascorbic acid, or a combination thereof. In some embodiments, the solvent includes water, an organic solvent, or a combination thereof. In some embodiments, the organic acid in the solution is in the range of 0.1 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, or any value in between, approximately that value, at least that value, at least approximately that value, up to that value, or up to approximately that value. In some embodiments, the liquid contains water, is essentially made from water, consists of water, or is water. In some embodiments, the reaction mixture is 0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.% A liquid and / or solvent comprising t.%, 25 wt.%, 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.%, 50 wt.%, 55 wt.%, 60 wt.%, or 65 wt.%, or any range of values ​​between them, an amount approximately that value, a maximum amount of that value, a maximum approximately that value, at least that value, or at least approximately that value.

[0060] In some embodiments, processing the reaction mixture includes heating the reaction mixture (e.g., baking it). In some embodiments, heating is performed at a temperature of 400°C, 425°C, 450°C, 475°C, 500°C, 525°C, 550°C, 575°C, 600°C, 625°C, 650°C, 675°C, 700°C, 725°C, 750°C, 775°C, 800°C, 825°C, 850°C, 875°C, 900°C, 925°C, 950°C, 975°C, 1000°C, 1025°C, 1050°C, 1075°C, 1100°C, 1125°C, 1150°C, 1175°C, 1200°C, 1225°C, or 1250°C, or any range of values ​​in between, about that temperature, at least that temperature, or at least about that temperature. For example, in some embodiments, the reaction mixture is heated to one of the following ranges or at approximately that temperature: 500°C to 1,000°C, 400°C to 500°C, 900°C to 1,100°C, 600°C to 900°C, or 750°C to 1,250°C.

[0061] In some embodiments, processing the reaction mixture further includes drying the reaction mixture. In some embodiments, drying the reaction mixture includes flash drying, paddle drying, or spray drying, or a combination thereof.

[0062] In some embodiments, processing the reaction mixture further includes calcining the reaction mixture. In some embodiments, calcination may be performed in a furnace. In some embodiments, the furnace includes a tubular furnace, rotary kiln, rotary furnace, roller hearth kiln, roller hearth furnace, batch furnace, batch drum furnace, or crucible pusher kiln, and a belt furnace, or a combination thereof.

[0063] In some embodiments, processing the reaction mixture further includes crushing the reaction mixture. In some embodiments, processing the reaction mixture further includes grinding the reaction mixture. In some embodiments, grinding the reaction mixture includes using a jet mill, roller mill, spiral jet mill, or ball mill, or a combination thereof.

[0064] In some embodiments, the method for preparing iron phosphate further includes the recovery of by-products. In some embodiments, the by-products are selected from the group consisting of H2, water, and combinations thereof. In some embodiments, the by-products contain H2. In some embodiments, the by-products contain water. In some embodiments, the by-products contain H2 and water. In some embodiments, the by-products can be recovered. In some embodiments, the by-products can be recycled.

[0065] Method for preparing lithium iron phosphate In some embodiments, methods for preparing lithium iron phosphate are described. In some embodiments, the method for preparing lithium iron phosphate includes combining iron phosphate (e.g., iron phosphate or iron phosphate compositions described herein) with a lithium source and a carbon source to form a calcined mixture, and processing the calcined mixture (e.g., calcining) to form lithium iron phosphate. Figure 6 schematically shows an exemplary method 600 for preparing lithium iron phosphate. As shown in Figure 6, method 600 includes combining iron phosphate, a lithium source and a carbon additive to form a calcined mixture 602. In some embodiments, combining includes combining iron phosphate, a lithium source and a carbon additive with a liquid. In some embodiments, the liquid is water. In some embodiments, combining includes grinding the calcined mixture. Method 600 further includes a step 604 of drying the calcined mixture. In some embodiments, drying includes spray drying the calcined mixture. In some embodiments, drying the calcined mixture includes forming a plurality of particles comprising the dried calcined mixture. Method 600 includes calcining the dried calcined mixture. In some embodiments, calcination includes calcining a plurality of particles comprising a dried calcined mixture.

[0066] In some embodiments, the molar ratio of lithium in the lithium source to iron in iron phosphate (i.e., Li:Fe) in the first mixture is within the range of any value between 2:1, 1.9:1, 1.8:1, 1.7:1, 1.6:1, 1.5:1, 1.4:1, 1.3:1, 1.2:1, 1.1:1, 1.09:1, 1.08:1, 1.07:1, 1.06:1, 1.05:1, 1.04:1, 1.03:1, 1.02:1, 1.01:1, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2, or any value between them, approximately, at least, or at least approximately. In some embodiments, the lithium source is selected from the group consisting of LiOH, LiOH·H2O, Li2CO3, LiPO3, Li3PO3, Li3PO4, LiH2PO4, Li2HPO4, LiH2PO3, Li2HPO3, lithium iron oxides, and their hydrate forms, as well as combinations thereof. In some embodiments, the carbon source is selected from the group consisting of sugars, natural polymers, synthetic polymers, carbonaceous materials, and combinations thereof. In some embodiments, the carbon source is selected from the group consisting of monosaccharides, disaccharides, oligosaccharides, starch, gum, polyvinyl alcohol (PVA), polyethylene glycol (PEG), sugar alcohols, pitch, coke, asphaltite, winter rock, asphalt, gilsonite, sweeteners, mannitol, erythritol, polyethylene-polypropylene-oxide block copolymer, detergents, fatty acids, fatty acid esters, modified starch, modified cellulose, carboxymethylcellulose, graphite, activated carbon, urea, polyvinylpyrrolidone (PVP), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and combinations thereof.

[0067] In some embodiments, grinding the first mixture involves grinding the first mixture to have a D90 particle size distribution of 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 3 μm, 4 μm, 5 μm, or any value in between, approximately that value, less than that value, approximately less than that value. The D90 particle size refers to the diameter in which 90% of the volume of the sample consists of particles smaller than this diameter.

[0068] In some embodiments, spray drying of the first mixture includes an inlet temperature of 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 250°C, 300°C, 400°C, or any range of values ​​between them, about that value, at least that value, at least about that value, maximum that value, maximum about that value. In some embodiments, spray drying the first mixture includes an outlet temperature of 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or any range of values ​​between them, about that value, at least that value, at least about that value, maximum that value, maximum about that value.

[0069] In some embodiments, calcination is carried out under an inert atmosphere. In some embodiments, calcination is carried out under nitrogen. In some embodiments, calcination is carried out under argon. In some embodiments, calcination is carried out at an oxidizing gas (e.g., air, oxygen, oxygen-containing gas, oxygen-enriched air) concentration of 0.05 vol.%, 0.1 vol.%, 0.2 vol.%, 0.3 vol.%, 0.4 vol.%, 0.5 vol.%, 0.6 vol.%, 0.7 vol.%, 0.8 vol.%, 0.9 vol.%, or 1 vol.%, or any range of values ​​between them, about that value, maximum that value, or maximum about that value. In some embodiments, calcination is carried out in the presence of a reducing gas selected from the group consisting of hydrogen methane, natural gas, propane, butane, carbon monoxide, and combinations thereof. In some embodiments, the concentration of the reducing gas is 0.5 vol.%, 1 vol.%, 1.5 vol.%, 2 vol.%, 2.5 vol.%, 3 vol.%, 3.5 vol.%, 4 vol.%, 4.5 vol.%, 5 vol.%, 5.5 vol.%, 6 vol.%, 6.5 vol.%, 7 vol.%, 7.5 vol.%, 8 vol.%, 8.5 vol.%, 9 vol.%, 9.5 vol.%, or 10 vol.%, or any range of values ​​between them, about that value, up to that value, or up to about that value. In some embodiments, the calcination is carried out under air, oxygen, oxygen-enriched air, and / or ozone. In some embodiments, the calcination is carried out under a mixture of gases. In some embodiments, for example, the calcination is carried out under a mixture of inert gas and reducing gas. In some embodiments, the calcination is carried out in a furnace such as a rotary furnace. In some embodiments, the duration of firing is 10 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 1.1 hours, 1.2 hours, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, or any range of values ​​in between, approximately that time, at least that time, at least approximately that time, up to that time, or up to approximately that time.In some embodiments, the firing temperature is in the range of 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1200°C, 1500°C, 2000°C, or any value in between, or is about that temperature, at least that temperature, at least about that temperature, at most that temperature, or at most about that temperature.

[0070] • Method for preparing electrode films In some embodiments, methods for preparing electrode films for energy storage devices are described. In some embodiments, the method for preparing electrode films for energy storage devices, as disclosed herein, includes forming lithium iron phosphate, combining a binder with lithium iron phosphate to form an electrode film mixture, and processing the electrode film mixture to form an electrode film. In some embodiments, combining the binder with lithium iron phosphate further includes combining it with a conductive additive.

[0071] In some embodiments, the electrode film is prepared by a wet method. In some embodiments, the electrode film is prepared by a dry method. In some embodiments, the dry method may refer to a method in which no solvent is used, or substantially no solvent is used, in forming the electrode film. For example, the components of the active layer or electrode film, including an active substance (e.g., lithium iron phosphate), a carbon additive, and / or a binder, may include dry particles. A dry particle active layer mixture may be provided by combining dry particles to form an active layer or electrode film. In some embodiments, the active layer or electrode film may be formed from a dry particle active layer mixture such that the weight percentage of the components of the active layer or electrode film is substantially the same as the weight percentage of the components of the dry particle active layer mixture. In some embodiments, the active layer or electrode film formed from a dry particle active layer mixture using a dry method may not contain, or substantially contain, any processing additives such as solvents and the resulting solvent residues. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed using a dry method from a dry particle mixture. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed using a dry method from a mixture of dry particles. The method for forming the active layer or electrode film may include fiberizing fibrous binder components such that the film contains a fibrous binder. In further embodiments, the self-supporting active layer or electrode film may be formed in the absence of a current collector. In even further embodiments, the active layer or electrode film may include a fibrous polymer matrix such that the film is self-supporting. It is conceivable that a matrix, grid, or web of filaments can be formed to give the electrode film a mechanical structure.

[0072] In some embodiments, the lithium iron phosphate in the electrode film mixture is 60 wt.%, 70 wt.%, 80 wt.%, 85 wt.%, 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, 99 wt.%, or any range in between, approximately that value, at least that value, at least approximately that value, maximum that value, or maximum approximately that value.

[0073] In some embodiments, the binder in the electrode film mixture is 20 wt.%, 15 wt.%, 10 wt.%, 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1.5 wt.%, or any range in between, about that value, at least that value, at least about that value, up to that value, or up to about that value. In some embodiments, the binder includes a polymer binder substance. The binder may include polytetrafluoroethylene (PTFE), polyolefins, polyalkylenes, polyethers, styrene-butadiene, polysiloxane copolymers, polysiloxanes, branched polyethers, polyvinyl ethers, copolymers thereof, and / or mixtures thereof. The binder may include cellulose, for example, carboxymethylcellulose (CMC). In some embodiments, the polyolefin may include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and / or mixtures thereof. For example, the binder may include polyvinyl chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, copolymers thereof, and / or mixtures thereof. In some embodiments, the binder may be a thermoplastic. In some embodiments, the binder includes a fibrous polymer. In certain embodiments, the binder includes PTFE, is essentially made from PTFE, or consists of PTFE. In some embodiments, the electrode film includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 types of binders, or at least that number of binders, or up to that number of binders.

[0074] In some embodiments, the conductive additive may include conductive carbon additives such as carbon black and / or carbon nanotubes. In some embodiments, the electrode film contains 6 wt.%, 5 wt.%, 4.5 wt.%, 4 wt.%, 3.5 wt.%, 3 wt.%, 2.5 wt.%, 2 wt.%, 1.5 wt.%, 1 wt.%, 0.5 wt.%, or any range in between, about that value, at least that value, at least about that value, maximum that value, or maximum about that value of the conductive additive. In some embodiments, the electrode film may not contain any conductive additive.

[0075] • Energy storage devices In some embodiments, the energy storage device includes, for example, a capacitor, a battery, a capacitor-battery hybrid, and / or a fuel cell. The energy storage device of this disclosure includes an electrolyte, a cathode, an anode, a separator, and a housing, the electrolyte, cathode, and anode being located within the housing. In some embodiments, the energy storage device provided herein is a lithium-ion battery. The cathode and anode each include an electrode film and a current collector forming an electrode. In some embodiments, the energy storage device includes an electrode film formed by a method disclosed herein. The electrode film generally includes one or more active materials, for example, lithium iron phosphate provided herein. [Examples]

[0076] Exemplary embodiments of the present disclosure, including methods, substances, and / or resulting products, are described in the following examples.

[0077] • Example 1 - Preparation of iron phosphate by solvent evaporation during reaction 105 g of iron powder was gradually added over 1 hour to 450 g of water and 225 g of 85% phosphoric acid, maintaining the reaction temperature at a maximum of 80°C, with an iron-to-phosphorus elemental ratio of 1:1.04. The reaction mixture was mixed for a total of 4 hours. The reaction mixture was then left undisturbed for 16 hours, after which the reaction product was a dry black solid / sponge-like substance. The material was pulverized and calcined at 900°C-950°C for approximately 2 hours to form a composition containing iron phosphate.

[0078] Example 2 - Preparation of iron phosphate by adding iron-based substances to a solution 105 g of iron powder was added at a rate of approximately 1 g / min to a solution containing 225 g of 85% phosphoric acid and 225 g of deionized water. The reaction mixture was mixed at 45°C, and the addition of iron powder was stopped as soon as the surface of the reaction mixture was covered with bubbles. The temperature of the reaction mixture rose to approximately 65°C during the reaction. When the reaction was complete, a paste with a low water / moisture content of approximately 25% was formed. The obtained paste was collected and calcined in air at 800°C for approximately 2 hours to form a composition containing iron phosphate.

[0079] Example 3 - Preparation of iron phosphate by adding phosphoric acid to solution 225 g of 85% phosphoric acid was added at a rate of approximately 1 g / min to a solution containing 105 g of iron powder and 225 g of deionized water. The reaction mixture was mixed at 45°C, and the addition of iron powder was stopped as soon as the surface of the reaction mixture was covered with bubbles. The temperature of the reaction mixture rose to approximately 65°C during the reaction. Upon completion of the reaction, a paste with a low water / moisture content of approximately 25% was formed. The resulting paste was collected and calcined in air at 800°C for approximately 2 hours to form a composition containing iron phosphate.

[0080] Figures 7A to 7D show images at different stages. Figure 7A is an image during the reaction. Figure 7B is an image of the paste formed at the end of the reaction, showing that the water has substantially evaporated. Figure 7C is an image of the paste after it has air-dried and been granulated. Figure 7D is an image of the particles after calcination.

[0081] • Example 4 - XRD analysis of iron phosphate composition X-ray diffraction (XRD) spectra of the iron phosphate compositions prepared in Example 2 were collected and compared with those of commercially available iron phosphate. Figure 7E shows the typical XRD patterns of the iron phosphate compositions compared to commercially available iron phosphate. As shown in Figure 7E, the iron phosphate compositions prepared by the method disclosed herein provided XRD spectra similar to those of commercially available iron phosphate.

[0082] Figure 8A further shows the XRD pattern of the iron phosphate composition prepared in Example 2, and Figure 8B shows the XRD pattern of commercially available iron phosphate. Here again, the iron phosphate composition prepared by the method disclosed herein provided an XRD spectrum similar to that of commercially available iron phosphate.

[0083] • Example 5 - XRD analysis of lithium iron phosphate substance Lithium iron phosphate was prepared using the iron phosphate composition prepared in Example 2. The XRD spectrum of the obtained lithium iron phosphate material was collected and compared with that of commercially available lithium iron phosphate. Figure 9A shows a typical XRD pattern of the lithium iron phosphate material prepared using the iron phosphate composition prepared in Example 2. Figure 9B shows a typical XRD pattern of commercially available lithium iron phosphate. As shown in Figures 9A and 9B, the lithium iron phosphate material prepared using the iron phosphate composition prepared by the method disclosed herein provided an XRD spectrum similar to that of commercially available lithium iron phosphate.

[0084] • Example 6 - Electrochemical performance of coin-type cells Cathode foils containing the lithium iron phosphate material described herein were prepared. Each electrode was generated and tested in a coin-type cell. Figure 10 shows the specific charge-discharge capacity of the cathode foils containing the lithium iron phosphate material described herein.

[0085] • Example 7 - Purity level of iron phosphate composition Table 1 summarizes the weight percentages of the elemental composition of the iron phosphate composition prepared in Example 2, compared to the elemental composition of four commercially available iron phosphate samples (Samples 1-4). [Table 1]

[0086] As summarized in Table 1, the purity level of the iron phosphate compositions prepared by the methods disclosed herein is the same as or higher than that of commercially available iron phosphate samples (Samples 1-4). For example, the iron phosphate composition prepared by the methods disclosed herein contains 0.001 wt.% magnesium, while Sample 1 contains 0.017 wt.% magnesium. Sample 2 contains 0.008 wt.% potassium, while the iron phosphate composition prepared by the methods disclosed herein contains 0.003 wt.% potassium. Sample 3 contains 0.032 wt.% sulfur, while the iron phosphate composition prepared by the methods disclosed herein contains 0.004 wt.% sulfur. Furthermore, Sample 4 contains 0.023 wt.% aluminum, while the iron phosphate composition prepared by the methods disclosed herein contains 0.002 wt.% aluminum.

[0087] • Example 8 - Purity level of lithium iron phosphate substance Table 2 summarizes the relative elemental composition of the lithium iron phosphate materials described herein, in weight percentage (i.e., wt.%), compared to a commercially available lithium iron phosphate sample (Sample 5). [Table 2]

[0088] As summarized in Table 2, the elemental composition of the lithium iron phosphate material prepared by the method disclosed herein was similar to that of commercially available lithium iron phosphate.

[0089] Example 9 - Preparation of iron phosphate by adding spherical iron particles to a solution 1000 g of iron powder was added at a rate of approximately 1 kg / hour in a stirred tank reactor to a solution containing 2075 g of 85% phosphoric acid and 2075 g of deionized water. The iron powder had a spherical shape and small particle size. The reaction mixture was mixed at 60°C and the iron powder was added. The temperature of the reaction mixture rose to a maximum of approximately 90°C during the reaction. The reaction was continued for 5 hours, allowing moisture to evaporate. After the reaction was complete, a paste was formed. The obtained paste was collected and dried in ambient air. The dried paste was then manually granulated and subsequently calcined in a batch furnace at 800°C in air for approximately 2 hours to form a composition containing iron phosphate.

[0090] Figures 11A to 11D show images at different stages. Figure 11A is an image during the stirring reaction. Figure 11B is an image of the paste formed at the end of the reaction, showing that the water has almost evaporated. Figure 11C is an image of the dried and granulated particles. Figure 11D is an image of the particles after calcination. Figure 12A is an SEM image of the calcined particles. Figure 12B is the XRD pattern of the calcined particles.

[0091] Example 10 - Preparation of iron phosphate by adding crude iron particles to a solution Ten kg of iron powder was added at a rate of approximately 1 kg / hour in a plowshaar mixer to a solution containing 24.3 kg of 75% phosphoric acid, 10 ml of defoaming agent, and 18.7 kg of deionized water. The iron powder was crude iron powder. The reaction mixture was mixed at 85°C, and the iron powder was added. The mixer was maintained at 85°C for 5 hours to allow the reaction to proceed and the water to evaporate. After the reaction was complete, a paste was formed. The resulting paste was collected and ground. The dried paste was then calcined in a rotary furnace in air at 840°C for approximately 1 hour to form a composition containing iron phosphate.

[0092] Figures 13A to 13D show images at different stages. Figures 13A and 13B show images of the products after the reaction. Figure 13C shows images of particles calcined in a rotary furnace. Figure 13D shows images of anhydrous particles collected after calcination. Figure 14 shows the XRD pattern of the calcined particles.

[0093] Example 11 - Preparation of lithium iron phosphate A slurry was formed by combining LiOH monohydrate, iron phosphate from Examples 1, 2, 3, 9, or 10, and sugar in deionized water. The molar ratio of Li in the LiOH monohydrate to iron in the iron phosphate was 1.04:1. The slurry was bead-ground, resulting in a D90 particle distribution of less than approximately 2 μm. The ground slurry was spray-dried at an inlet temperature of 220°C and an outlet temperature of 110°C to obtain a dry powder. The dry powder was calcined at 760°C for 2 hours under a nitrogen atmosphere. The calcined product was crushed and granulated to obtain the final lithium iron phosphate particles.

[0094] While certain embodiments of the present invention have been described, these embodiments are presented only as examples and are not intended to limit the scope of this disclosure. In fact, the novel methods and systems described herein can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications of the systems and methods described herein can be made without departing from the spirit of this disclosure. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of this disclosure. Accordingly, the scope of the present invention is defined solely by reference to the appended claims.

[0095] Any features, substances, properties, or groups described in relation to a particular aspect, embodiment, or example should be understood to be applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, insofar as it does not conflict with the description thereof. All features disclosed herein (including any appended claims, abstract, and drawings) and / or all methods or steps of any method so disclosed herein may be combined in any combination, except for any combination in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any of the aforementioned embodiments. Protection extends to any novel features or any novel combination of features disclosed herein (including any appended claims, abstract, and drawings), or any novel methods or steps of any method so disclosed herein.

[0096] Furthermore, certain features described in this disclosure in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable partial combination in multiple embodiments. Furthermore, features may be described above as acting in a particular combination, but one or more features from a claimed combination may, in some cases, be removed from the combination, and the combination may be claimed as a partial combination or a variation of a partial combination.

[0097] Furthermore, while operations may be shown in the drawings or described herein in a specific order, such operations do not need to be performed in the specific order shown or in a sequential order, or not all operations need to be performed, in order to achieve the desired result. Other operations not shown or described may be incorporated into exemplary methods and procedures. For example, one or more additional operations may be performed before, after, simultaneously with, or in between any of the described operations. Furthermore, operations may be rearranged or reordered in other embodiments. Those skilled in the art will understand that in some embodiments, the actual steps performed in the illustrated and / or disclosed methods may differ from those shown in the drawings. Depending on the embodiment, certain steps among the steps described above may be omitted, or other steps may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of this disclosure. Also, the separation of various system components in the above embodiments should not be understood as requiring such separation in all embodiments, and the described components and systems may generally be integrated together in a single product or packaged in multiple products. For example, any of the components of the energy storage system described herein may be provided separately or incorporated together to form the energy storage system (for example, they may be packaged together or mounted together).

[0098] For the purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not all such advantages can necessarily be achieved according to any particular embodiment. Thus, for example, a person skilled in the art will recognize that this disclosure can be embodied or implemented to achieve one or more advantages as taught herein, without necessarily achieving other advantages that can be taught or suggested herein.

[0099] Conditional language such as “can,” “could,” “might,” or “may,” unless otherwise specified or understood in the context in which they are used, is generally intended to convey that a particular embodiment includes a particular feature, element, and / or process, but other embodiments do not. Thus, such conditional language is generally not intended to mean that the feature, element, and / or process is somehow required in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or processes should be included in or performed in any particular embodiment, with or without user input or prompting.

[0100] Conjunctional phrases such as “at least one of X, Y, and Z” are generally understood in contexts where they convey that an item, term, etc., could be any of X, Y, or Z, unless otherwise specified. Therefore, such conjunctional phrases are not generally intended to imply that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0101] Terms expressing degree as used herein, such as “approximately,” “about,” “generally,” and “substantially,” represent values, quantities, or characteristics close to the stated values, quantities, or characteristics that still perform the desired function or achieve the desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to quantities less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the stated quantity, depending on the desired function or desired result.

[0102] The scope of this disclosure is not intended to be limited by specific disclosures of preferred embodiments in this section or elsewhere in this specification, but may be defined by the claims, as presented in this section or elsewhere in this specification, or as presented in the future. The language of the claims should be interpreted broadly on the basis of the language used in the claims, and should be interpreted as non-exclusive, not limited to the examples described herein or during the examination of this application.

Claims

1. A method for preparing iron phosphate, A step of combining an iron-based substance, phosphoric acid, and a liquid to form a reaction reaction containing iron phosphate, wherein the molar ratio of the iron-based substance to the phosphoric acid is approximately 1:1.5 to 1.5:

1. A step of treating the reaction mixture to form a composition containing iron phosphate, Methods that include...

2. The method according to claim 1, wherein the iron-based substance contains iron metal.

3. The method according to claim 1 or 2, wherein the iron-based substance contains at least 95% iron.

4. The aforementioned iron-based material is D, which is approximately 1 μm to 500 μm in size. ５０ The method according to any one of claims 1 to 3, comprising iron-based powder particles having a particle size distribution.

5. The method according to claim 4, wherein the iron-based powder particles include a spherical shape.

6. The method according to any one of claims 1 to 5, wherein the iron-based substance includes iron scrap metal.

7. The method according to any one of claims 1 to 6, wherein the combining step includes adding the iron-based substance to the solution containing the liquid and phosphoric acid at a rate of about 0.1 g / min to about 1,000 g / min.

8. The method according to any one of claims 1 to 6, wherein the combining step includes adding phosphoric acid to the liquid and the solution containing the iron-based substance at a rate of about 0.1 g / min to about 1,000 g / min.

9. The method according to any one of claims 1 to 8, wherein the step of processing the reaction mixture includes heating the reaction mixture to a temperature in the range of approximately 500°C to 1000°C.

10. The method according to any one of claims 1 to 9, wherein the step of treating the reaction mixture includes at least one of drying, calcination, and crushing.

11. The method according to any one of claims 1 to 10, wherein the composition comprises at least 33 wt.% iron and at least 18 wt.% phosphorus.

12. The method according to any one of claims 1 to 11, wherein the composition comprises at least 38 wt.% iron and at least 22 wt.% phosphorus.

13. The method according to any one of claims 1 to 12, wherein the composition contains less than 0.01 wt.% magnesium.

14. The method according to any one of claims 1 to 13, wherein the total impurities of the composition are less than 1 wt.%.

15. The method according to any one of claims 1 to 14, wherein the liquid includes water.

16. The method according to any one of claims 1 to 15, wherein the reaction mixture comprises at least about 20 wt.% of the liquid.

17. The method according to any one of claims 1 to 16, wherein the molar ratio of the iron-based substance to phosphoric acid is about 1:1.25 to 1.25:

1.

18. The method according to any one of claims 1 to 17, further comprising the step of recovering by-products.

19. The aforementioned by-product is H ２ The method according to claim 18, comprising a substance selected from the group consisting of water and combinations thereof.

20. A method for preparing lithium iron phosphate, A step of forming a composition containing iron phosphate according to the method of any one of claims 1 to 19, A step of combining the composition with a lithium source and a carbon source to form a calcined mixture, A step of calcining the calcined mixture to form lithium iron phosphate, Methods that include...

21. The method according to claim 20, wherein the combining step includes combining with a liquid to form the calcined mixture.

22. The method according to claim 20 or 21, further comprising the step of spray-drying the calcined mixture.

23. The method according to any one of claims 20 to 22, further comprising the step of grinding the calcined mixture.

24. A method for preparing electrode films for energy storage devices, A step of forming lithium iron phosphate according to the method of any one of claims 20 to 23, A step of combining a binder and lithium iron phosphate to form an electrode film mixture, A step of processing the electrode film mixture to form an electrode film, Methods that include...

25. The method according to claim 24, wherein the step of combining the binder with lithium iron phosphate includes combining the binder and conductive carbon with lithium iron phosphate.

Images