Iron phosphate synthesis which reduces waste products, and compositions thereof

Abstract

Processes for preparing iron phosphate and electrode films for an energy storage device, with no solid or liquid waste, are described. Compositions including iron phosphate prepared by the processes disclosed herein are also described.

Description

TSLA.787WO PATENT IRON PHOSPHATE SYNTHESIS WHICH REDUCES WASTE PRODUCTS, AND COMPOSITIONS THEREOF INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified, for example, in the Application Data Sheet or Request as filed with the present application are hereby incorporated by reference under 37 CFR 1.57, and Rules 4.18 and 20.6, such as U.S. Provisional Application No.63 / 527,272, filed July 17, 2023, and which is hereby incorporated by reference in its entirety. BACKGROUND Field

[0002] The present disclosure relates generally to energy storage devices, and specifically to processes for preparing energy storage device active materials, active material precursors and compositions comprising the same. Description of the Related Art

[0003] Lithium-ion batteries are desirable for their optimized cost, safety, lifespan and moderate energy density. Current methods of cathode manufacturing require a large number of steps and can produce substantial quantities of waste products. For example, some conventional cathode material manufacturing processes of iron phosphate, a precursor to lithium iron phosphate active materials, require multiple chemical steps that produce waste products that are not easily recycled or disposed of. Thus, new methods for manufacturing active material precursors and / or active materials may aid to decrease the end-use cost of energy storage devices (e.g., lithium-ion batteries). SUMMARY

[0004] For purposes of summarizing the disclosure and the advantages achieved over the prior art, certain objects and advantages of the disclosure are described herein. Not all such objects or advantages may be achieved in any particular embodiment. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carriedout in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0005] All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.

[0006] In one aspect, a process of preparing iron phosphate is described. The process comprises: combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture comprising iron phosphate, wherein the molar ratio of the iron-based material to phosphoric acid is about 1:1.5 to 1.5:1; and processing the reaction mixture to form a composition comprising iron phosphate.

[0007] In some embodiments, the iron-based material comprises iron metal. In some embodiments, wherein the iron-based material comprises at least 95% iron. In some embodiments, the iron-based material comprises iron-based powder particles comprising a D50SDUWLFOH^ VL]H^ GLVWULEXWLRQ^ RI^ DERXW^ ^^ ^P^– ^^^^ ^P^^ ^ ,Q^ VRPH^ HPERGLPHQWV^^ WKH^ LURQ-based powder particles comprise a spherical morphology. In some embodiments, the iron-based material comprises iron scrap metal.

[0008] In some embodiments, combining comprises adding the iron-based material into a solution comprising the liquid and phosphoric acid at a rate from about 0.1 g per minute to about 1,000 g per minute. In some embodiments, combining comprises adding phosphoric acid into a solution comprising the liquid and the iron-based material at a rate from about 0.1 g per minute to about 1,000 g per minute. In some embodiments, processing the reaction mixture comprises heating the reaction mixture to at a temperature in a range of about 500 °C – 1000 °C. In some embodiments, the processing the reaction mixture comprises at least one of drying, calcination and crushing.

[0009] In some embodiments, the composition comprises at least 33 wt.% iron and at least 18 wt.% phosphorus. In some embodiments, the composition comprises at least 38 wt.% iron and at least 22 wt.% phosphorus. In some embodiments, the composition comprises less than 1 wt.% total impurities. In some embodiments, the composition comprises less than0.01 wt.% magnesium. In some embodiments, the liquid comprises water. In some embodiments, the reaction mixture comprises an amount of the liquid of at least about 20 wt.%. In some embodiments, the molar ratio of the iron-based material to phosphoric acid is about 1:1.25 to 1.25:1. In some embodiments, the process further comprises recovering a byproduct. In some embodiments, the byproduct comprises a material selected from the group consisting of H2, water, and combinations thereof.

[0010] In another aspect, a process of preparing lithium iron phosphate is described. The process comprises: forming the composition comprising iron phosphate according to the process disclosed herein; combining the composition with a lithium source and a carbon source to form a calcination mixture; and calcinating the calcination mixture to form lithium iron phosphate. In some embodiments, the combining comprises combining with a liquid to form the calcination mixture. In some embodiments, the process further comprises spray drying the calcination mixture. In some embodiments, the process further comprises milling the calcination mixture.

[0011] In another aspect, a process of preparing an electrode film for an energy storage device is described. The process comprises: forming the lithium iron phosphate according to the process disclosed herein; combining a binder with the 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 combining the binder with the lithium iron phosphate comprises combining the binder and a conductive carbon with the lithium iron phosphate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a flowchart of an example prior art process for preparing iron phosphate.

[0014] FIG. 2 is a flowchart of a process for preparing iron phosphate, according to one embodiment.

[0015] FIG. 3 is a flowchart of a process for preparing iron phosphate, according to one embodiment.

[0016] FIG. 4 is a flowchart of two processes for preparing iron phosphate, according to some embodiments.

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

[0018] FIGS.5B and 5C are images of an iron-based material powder particles with undefined morphologies, according to some embodiments.

[0019] FIG. 6 is a flowchart of a process for preparing lithium iron phosphate, according to one embodiment.

[0020] FIG. 7A is an image of the reactants for forming FePO4during the stir reaction according to one embodiment.

[0021] FIG.7B is an image of the formed paste at the end of the reaction according to one embodiment.

[0022] FIG. 7C is an image of the naturally dried and grinded paste according to one embodiment.

[0023] FIG. 7D is an image of the particles after calcination according to one embodiment.

[0024] FIG. 7E is an XRD pattern of iron phosphate composition prepared by a process according to one embodiment, relative to commercially available iron phosphate.

[0025] FIG. 8A is an XRD pattern of iron phosphate composition prepared by a process according to one embodiment, compared to a standard.

[0026] FIG. 8B is an XRD pattern of a commercially available iron phosphate, compared to a standard.

[0027] FIG.9A is an XRD pattern of lithium iron phosphate composition prepared by a process according to one embodiment, compared to a standard.

[0028] FIG. 9B is an XRD pattern of commercially available lithium iron phosphate, compared to a standard.

[0029] FIG. 10 is a graph of the specific charge capacity and specific discharge capacity of a coin cell including lithium iron phosphate material prepared by a process according to one embodiment.

[0030] FIG. 11A is an image of the reactants for forming FePO4 during the stir reaction according to one embodiment.

[0031] FIG. 11B is an image of the formed paste once the reaction is completed according to one embodiment.

[0032] FIG. 11C is an image of the dried and grinded FePO4hydrate particles according to one embodiment.

[0033] FIG.11D is an image of the FePO4 particles after calcination.

[0034] FIG. 12A is an SEM image of the calcinated FePO4 particles according to one embodiment.

[0035] FIG.12B is an XRD pattern of the FePO4calcinated particles according to one embodiment.

[0036] FIGS.13A and 13B are images of the product after the reaction is completed according to one embodiment.

[0037] FIG. 13C is an image of particles calcinated in a rotary furnace according to one embodiment.

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

[0039] FIG. 14 is an XRD pattern of the calcinated FePO4particles according to one embodiment. DETAILED DESCRIPTION Definitions

[0040] As used herein, the terms “battery” and “capacitor” are to be given their ordinary and customary meanings to a person of ordinary skill in the art. The terms “battery” and “capacitor” are nonexclusive of each other. A capacitor or battery can refer to a single electrochemical cell that may be operated alone, or operated as a component of a multi-cell system.

[0041] As provided herein, a “self-supporting” electrode film or active layer is an electrode film or layer that incorporates binder matrix structures sufficient to support the film or layer and maintain its shape such that the electrode film or layer can be free-standing. When incorporated in an energy storage device, a self-supporting electrode film or active layer is one that incorporates such binder matrix structures. Generally, and depending on the methods employed, such electrode films or active layers are strong enough to be employed in energy storage device fabrication processes without any outside supporting elements, such as a current collector or other film. For example, a “self-supporting” electrode film can have sufficientstrength to be rolled, handled, and unrolled within an electrode fabrication process without other supporting elements.

[0042] As provided herein, a “solvent-free” electrode film is an electrode film that contains no detectable processing solvents, processing solvent residues, or processing solvent impurities. Processing solvents or traditional solvents include organic solvents. A dry electrode film, such as a cathode electrode film or an anode electrode film, may be solvent- free.

[0043] A “wet” electrode or “wet process” electrode is an electrode prepared by at least one step involving a slurry of active material(s), binder(s), and processing solvents, processing solvent residues, and / or processing solvent impurities. A wet electrode may optionally include additive(s).

[0044] As used herein, the terms “calcinating” and “calcining” are to be used interchangeably, referring to heating a substance to a high temperature in the presence of an atmosphere, causing thermal decomposition, phase transition, and / or the removal of a volatile fraction. Description

[0045] The present disclosure may be understood by reference to the following detailed description. It is noted that, for purposes of illustrative clarity, certain elements in various drawings may not be drawn to scale, may be represented schematically or conceptually, or otherwise may not correspond exactly to certain physical configurations of embodiments.

[0046] FIG.1 illustrates typical example process 100 for preparing iron phosphate. Process 100 includes providing an iron sulfate hydrate intermediate (e.g., FeSO4ڄ7H2O) 101. The iron sulfate hydrate intermediate is formed by dissolving iron in sulfuric acid with hydrogen gas as a byproduct 102. The iron sulfate hydrate intermediate is a raw material from other industries, such as from the TiO2 industry. The iron-sulfate hydrate intermediate is mixed and dispersed with phosphoric acid or ammonium dihydrogen phosphate 104, and then oxidation and precipitation will occur once H2O2 / NaOH and / or NH3is added 106, the mixture is filtered and washed to give off Na2SO4or (NH4)2SO4108 and other dissolvable impurities, and then the mixture is flashed dried 110 to give off water and form an iron phosphate hydrate. The iron phosphate hydrate is calcinated, crushed and milled to form an anhydrous ironphosphate 112. The process generates large amount of Na2SO4or (NH4)2SO4effluent, which are soluble in water and may pollute the soil if not stored properly. In addition, the process may require large amount of water to remove impurities from the obtained FePO4. In addition, the process requires high infrastructure investment, complicated process control, and involves various chemicals each step.

[0047] Provided herein are various embodiments of processes of preparing iron phosphate, and compositions thereof. The disclosed processes provide a simplified route to prepare iron phosphate, for example by eliminating processing steps such as slurry preparation (including steps such as dispersion and wet milling), oxidation, precipitation, filtration, washing, and / or drying. The disclosed processes may greatly reduce undesired effluent. In some embodiments, processes of preparing iron phosphate with no or substantially no solid or liquid waste are disclosed. In some embodiments, byproducts formed in the processes of preparing iron phosphate may be recycled into the process and / or utilized. In some embodiments, the disclosed processes provide morphology control. In some embodiments, the disclosed processes may optimize the lithium and carbon sources for calcination. In some embodiments, the disclosed processes generate a useful byproduct of hydrogen gas. In some embodiments, the hydrogen gas produced in the processes can be used in the step of calcinating the lithium iron phosphate. In some embodiments, the disclosed processes and / or systems may accommodate semi solid-state or solid-state synthesis. The process of the present disclosure may include combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture; and processing the reaction mixture to form a composition comprising iron phosphate.

[0048] In some embodiments, a composition comprising iron phosphate is described. In some embodiments, the composition comprises an amount of iron phosphate of, of about, of at least, or of at least about, 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. %, 63.9 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.%, 95wt.% or 98 wt.%, 99 wt.%, 100 wt.%, or any range of values therebetween. For example, in some embodiments, the amount of iron in the composition comprising iron phosphate is or is about in any one ofthe following ranges: 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 composition comprising iron phosphate is, is about, is at least, or is at least about, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19wt.%, 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. %, 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 range of values therebetween. For example, in some embodiments, the amount of phosphorus in the composition comprising iron phosphate is or is about in any one of the following ranges: 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 composition comprising iron phosphate comprises impurities. In some embodiments, the composition comprises a total amount of impurities of, of about, of at most, or of at most about, 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. %, 0.011 wt. %, 0.012 wt. %, 0.013 wt. %, 0.014 wt. %, 0.015 wt. %, 0.016 wt. %, 0.017 wt. %, 0.018 wt. %, 0.019 wt. %, 0.02 wt. %, 0.021 wt. %, 0.022 wt. %, 0.023 wt. %, 0.024 wt. %, 0.025 wt. %, 0.026 wt. %, 0.027 wt. %, 0.028 wt. %, 0.029 wt. %, 0.03 wt. %, 0.031 wt. %, 0.032 wt. %, 0.033 wt. %, 0.034 wt. %, 0.035 wt. %, 0.036 wt. %, 0.037 wt. %, 0.038 wt. %, 0.039 wt. %, 0.04 wt. %, 0.041 wt. %, 0.042 wt. %, 0.043 wt. %, 0.044 wt. %, 0.045 wt. %, 0.046 wt. %, 0.047 wt. %, 0.048 wt. %, 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 therebetween. 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 comprises an amount of each elemental impurity (e.g., Al, Ca, Co, Cr, Cu, K, Mg, Mn, Na, Ni, Pb, S, Si, Ti, Zn or Zr) of, of about, of at most, or of at most about, 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. %, 0.011 wt. %,0.012 wt. %, 0.013 wt. %, 0.014 wt. %, 0.015 wt. %, 0.016 wt. %, 0.017 wt. %, 0.018 wt. %, 0.019 wt. %, 0.02 wt. %, 0.021 wt. %, 0.022 wt. %, 0.023 wt. %, 0.024 wt. %, 0.025 wt. %, 0.026 wt. %, 0.027 wt. %, 0.028 wt. %, 0.029 wt. %, 0.03 wt. %, 0.031 wt. %, 0.032 wt. %, 0.033 wt. %, 0.034 wt. %, 0.035 wt. %, 0.036 wt. %, 0.037 wt. %, 0.038 wt. %, 0.039 wt. %, 0.04 wt. %, 0.041 wt. %, 0.042 wt. %, 0.043 wt. %, 0.044 wt. %, 0.045 wt. %, 0.046 wt. %, 0.047 wt. %, 0.048 wt. %, 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 therebetween. Iron Phosphate Preparation Process

[0050] One aspect of the present disclosure relates to a process of preparing iron phosphate. In some embodiments, the process of preparing iron phosphate includes combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture; and processing the reaction mixture to form a composition comprising iron phosphate. In some embodiments, the reaction mixture comprises iron phosphate. In some embodiments, the reaction mixture is dried directly after the reaction mixture is formed. In some embodiments, only one acid is used. In some embodiments, an intermediate sulfate is not formed. In some embodiments, sulfuric acid is not utilized. In some embodiments, an oxidation process is not utilized.

[0051] FIG.2 is a flowchart of process 200 for preparing iron phosphate, according to one embodiment. Process 200 includes combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture comprising iron phosphate 202. The process further includes processing the reaction mixture to form a composition comprising iron phosphate 204.

[0052] FIG. 3 illustrates another process 300 for preparing iron phosphate, according to one embodiment. Process 300 includes combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture comprising iron phosphate 302. The reaction mixture is dried to form a composition comprising lithium iron phosphate hydrate 304. The process further includes processing the composition to form iron phosphate 306.

[0053] FIG.4 is a flowchart of two processes for preparing iron phosphate, Option 1 and Option 2. Option 1 of FIG. 4 includes combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture 402, wherein the majority of the liquid is evaporated during the exothermic reaction. The reaction mixture is then processed bycalcination 404, crushing and / or milling to form a composition comprising iron phosphate. Option 2 of FIG.4 includes combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture 402. The reaction mixture is then actively dried 406 and processed by calcination 404, crushing and / or milling to form a composition comprising iron phosphate.

[0054] In some embodiments, the molar ratio of the iron-based material to phosphoric acid is, is about, is at least, or is at least about, 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 range of values therebetween. For example, in some embodiments, the molar ratio of the iron-based material to phosphoric acid is or is about in any one of the following ranges: 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, the iron-based material is added to the phosphoric acid and the liquid to form a reaction mixture. In some embodiments, phosphoric acid is added to the iron-based material and liquid to form a reaction mixture. In some embodiments, phosphoric acid and the iron-based material are combined at a rate of, of about, of at least, or at least about, 0.1 g per minute, 1 g per minute, 10 g per minute, 100 g per minute, 500 g per minute or 1,000 g per minute, or any range of values therebetween.

[0056] The iron-based material comprises iron. In some embodiments, the iron- based material comprises iron metal (e.g., iron scrap metal). In some embodiments, the iron- based material comprises an iron powder intermediate. In some embodiments, the surface of the iron powder intermediate is modified relative to the iron-based material, for example such that the iron powder intermediate has improved reaction kinetics with acid relative to an unmodified iron powder thereby resulting in a shortened reaction time. In other words, in some embodiments the modified surface of the iron powder intermediate facilitates the reaction between the iron-based material and the acid in preparing iron phosphate. In some embodiments, the iron-based material comprises an amount of iron of, of about, of at least, or of at least about, 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 therebetween. For example, in some embodiments, the amount of iron in the iron-based material is or is about in any one of the following ranges: 90-99 wt.%, 85-95 wt.%, 95-99 wt.%, 94-96 wt.%, or 93-97 wt.%.

[0057] In some embodiments, the iron-based material comprises powder particles comprising a D50 particle size distribution of, of about, of at least, or at least about, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm, 410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm, 490 μm, 500 μm, 510 μm, 520 μm, 530 μm, 540 μm or 550 μm, or any range of values therebetween. For example, in some embodiments, the D50 particle size distribution of the powder particles is or is about in any one of the following ranges: 1 μm - 500 μm, 1 μm - 100 μm, 100 μm - 200 μm, 200 μm - 300 μm, 300 μm - 400 μm, or 400 μm - 500 μm. The D50 particle size represents the median of particle size distributions, at which 50% of the sample’s volume has a smaller particle size, i.e., the D50particle size splits the distribution with half above and half below this particle size.

[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. By way of example, FIG. 5A is an image of a spherical iron-based powder particles, and FIGS. 5B and 5C are images of an iron-based powder particles with an undefined morphology.

[0059] In some embodiments, the liquid comprise water, an organic solvent, a solution, or combinations thereof. In some embodiments, the liquid comprises a defoamer. In some embodiments, the defoamer comprises a silicone-based defoamer, an oil-based defoamer, or a combination thereof. In some embodiments, the liquid is a solution comprising an organic acid dissolved in a solvent. In some embodiments, the organic acid comprises oxalic acid, oxalic acid hydrate, citric acid, ascorbic acid, or combinations thereof. In some embodiments, the solvent comprises water, organic solvent, or combinations thereof. In some embodiments, the organic acid in the solution is, is about, is at least, is at least about, is at most, is at most about, 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 range of values therebetween, of the iron basedmaterial and / or the liquid. In some embodiments the liquid comprises, consists essentially of, consists of, or is water. In some embodiments, the reaction mixture comprises an amount of liquid and / or solvent of, of about, of at most, of at most about, of at least, or of at least about, 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. %, 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 therebetween.

[0060] In some embodiments, processing the reaction mixture comprises heating (e.g., calcinating) the reaction mixture. In some embodiments, heating is performed to at a temperature of, of about, of at least, or at least about, 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 therebetween. For example, in some embodiments, the reaction mixture is heated at or at about in any one of the following ranges: 500 °C – 1,000 °C, 400 °C – 500 °C, 900 °C – 1,100 °C, 600 °C – 900 °C, or 750 °C – 1,250 °C.

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

[0062] In some embodiments, processing the reaction mixture further comprises calcinating the reaction mixture. In some embodiments, calcination may be carried out in a furnace. In some embodiments, the furnace comprises tube furnace, a rotary kiln, a rotary furnace, a roller hearth kiln, a roller hearth furnace, a batch furnace, a batch drum furnace, or a crucible pusher kiln, and belt furnace or combinations thereof.

[0063] In some embodiments, processing the reaction mixture further comprises crushing the reaction mixture. In some embodiments, processing the reaction mixture further comprises milling the reaction mixture. In some embodiments, milling the reaction mixture includes jet milling, roller milling, spiral jet milling, or ball milling, or combinations thereof.

[0064] In some embodiments, the process of preparing iron phosphate further includes the recovery of a byproduct. In some embodiments, the byproduct is selected fromthe group consisting of H2, water, and combinations thereof. In some embodiments, the byproduct comprises H2. In some embodiments, the byproduct comprises water. In some embodiments, the byproduct comprises H2 and water. In some embodiments, the byproduct can be recovered. In some embodiments, the byproduct can be recycled. Lithium Iron Phosphate Preparation Process

[0065] In some embodiments, a process of preparing lithium iron phosphate is described. In some embodiments, the process of preparing lithium iron phosphate includes combining iron phosphate (e.g., the iron phosphate or iron phosphate composition as described herein) with a lithium source and a carbon source to form a calcination mixture; and processing (e.g., calcinating) the calcination mixture to form lithium iron phosphate. FIG.6 schematically illustrates an example process 600 for preparing lithium iron phosphate. As illustrated in FIG. 6, the process 600 comprises combining an iron phosphate, a lithium source and a carbon additive to form a calcination mixture 602. In some embodiments, the combining comprises combing the iron phosphate, the lithium source and the carbon additive with a liquid. In some embodiments, the liquid is water. In some embodiments, the combining comprises milling the calcination mixture. The process 600 further comprises a step of drying the calcination mixture 604. In some embodiments, the drying comprises spray drying the calcination mixture. In some embodiments, the drying the calcination mixture comprises forming a plurality of particles comprising the dried calcination mixture. The process 600 comprises calcinating the dried calcination mixture. In some embodiments, the calcinating comprises calcinating the plurality of particles comprising the dried calcination mixture.

[0066] In some embodiments, the molar ratio of lithium in the lithium source to the iron in the iron phosphate (i.e., Li:Fe) in the first mixture is, is about, is at least, or is at least about, 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 range of values therebetween. In some embodiments, the lithium source is selected from the group consisting of LiOH, LiOHyH2O, Li2CO3, LiPO3, Li3PO3, Li3PO4, LiH2PO4, Li2HPO4, LiH2PO3, Li2HPO3, lithium iron oxides, and hydrates forms thereof, and combinations thereof. In some embodiments, the carbon source is selected from the group consisting of a sugar, a natural polymer, a synthetic polymer, a carbonaceousmaterial, and combinations thereof. In some embodiments, the carbon source is selected from the group consisting of a monosaccharide, a disaccharide, an oligosaccharide, a starch, a gum, polyvinyl alcohol (PVA), polyethylene glycol (PEG), a sugar alcohol, pitch, coke, asphaltite, uintahite, asphaltum, gilsonite, sweeteners, mannitol, erythritol, polyethylene-polypropylene- oxide block copolymers, detergents, fatty acids, fatty acid esters, modified starches, modified celluloses, carboxy methyl cellulose, graphite, activated carbon, urea, polyvinylpyrrolidone (PVP), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and combinations thereof.

[0067] In some embodiments, milling the first mixture comprises milling the first mixture to a have a D90 particle size distribution of, of about, of less than, of less than about, 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 range of values therebetween. The D90 particle size refers to the diameter at which 90% of the sample's volume is composed of particles smaller than this diameter.

[0068] In some embodiments, spray drying the first mixture comprises an inlet temperature of, of about, of at least, of at least about, of at most, of at most about, 100oC, 110oC, 120oC, 130oC, 140oC, 150oC, 160oC, 170oC, 180oC, 190oC, 200oC, 210oC, 220oC, 230oC, 250oC, 300oC, 400oC, or any range of values therebetween. In some embodiments, spray drying the first mixture comprises an outlet temperature of, of about, of at least, of at least about, of at most, of at most about, 50oC, 60oC, 70oC, 80oC, 90oC, 100oC, 110oC, 120oC, 130oC, 140oC, 150oC, 160oC, 170oC, 180oC, 190oC, 200oC, or any range of values therebetween.

[0069] In some embodiments, the calcination is performed under an inert atmosphere. In some embodiments, calcination is performed under nitrogen. In some embodiments, the calcination is performed under argon. In some embodiments, the calcination is performed at an oxidizing gas (e.g., air, oxygen, oxygen-containing gas, oxygen enriched air) concentration of, of about, of at most, or of at most about, 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 therebetween. In some embodiments, the calcination is performed 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, theconcentration of the reducing gas is, is about, is at most, or is at most about, 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 therebetween. In some embodiments, the calcination is performed under air, oxygen, oxygen enriched air, and / or ozone. In some embodiments, the calcination is performed under a mixture of gasses. In some embodiments, for example, the calcination is performed under a mixture of an inert gas a reducing gas. In some embodiments, the calcination is performed in a furnace such as a rotary furnace. In some embodiments, the duration of the calcination is, is about, is at least, is at least about, is at most, is at most about, 10 min, 30 min, 40 min, 50 min, 60 min, 1.1 h, 1.2 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 7 h, 8 h, 9 h, 10 h, or any range of values therebetween. In some embodiments, the temperature of the calcination is, is about, is at least, is at least about, is at most, is at most about, 100oC, 200oC, 300oC, 400oC, 500oC, 600oC, 700oC, 800oC, 900oC, 1000oC, 1200oC, 1500oC, 2000oC, or any range of values therebetween. Electrode Film Preparation Process

[0070] In some embodiments, a process of preparing an electrode film for an energy storage device is described. In some embodiments, the process of preparing an electrode film for an energy storage device includes forming the lithium iron phosphate as disclosed herein, combining a binder with the 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 the lithium iron phosphate further comprises combining with a conductive additive.

[0071] In some embodiments, the electrode film is prepared by a wet process. In some embodiments, the electrode film is prepared by a dry fabrication process. In some embodiments, the dry fabrication process can refer to a process in which no or substantially no solvents are used in the formation of an electrode film. For example, components of the active layer or electrode film, including the active material (e.g., lithium iron phosphate), carbon additives and / or binders, may comprise dry particles. The dry particles for forming the active layer or electrode film may be combined to provide a dry particle active layer mixture. In some embodiments, the active layer or electrode film may be formed from the dry particle activelayer mixture such that weight percentages of the components of the active layer or electrode film and weight percentages of the components of the dry particles active layer mixture are substantially the same. In some embodiments, the active layer or electrode film formed from the dry particle active layer mixture using the dry fabrication process may be free from, or substantially free from, any processing additives such as solvents and solvent residues resulting therefrom. In some embodiments, the resulting active layer or electrode films are self- supporting films formed using the dry process from the dry particle mixture. In some embodiments, the resulting active layer or electrode films are free-standing films formed using the dry process from the dry particle mixture. A process for forming an active layer or electrode film can include fibrillizing the fibrillizable binder component(s) such that the film comprises fibrillized binder. In further embodiments, a free-standing active layer or electrode film may be formed in the absence of a current collector. In still further embodiments, an active layer or electrode film may comprise a fibrillized polymer matrix such that the film is self-supporting. It is thought that a matrix, lattice, or web of fibrils can be formed to provide mechanical structure to the electrode film.

[0072] In some embodiments, the lithium iron phosphate in the electrode film mixture is, is about, is at least, is at least about, is at most, is at most about, 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 ranges therebetween.

[0073] In some embodiments, the binder in the electrode film mixture is, is about, is at least, is at least about, is at most, is at most about, 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 ranges therebetween. In some embodiments, the binder comprises a polymeric binder material. The binder can include polytetrafluoroethylene (PTFE), a polyolefin, polyalkylenes, polyethers, styrene- butadiene, co-polymers of polysiloxanes, a polysiloxane, branched polyethers, polyvinylethers, co-polymers thereof, and / or admixtures thereof. The binder can include a cellulose, for example, carboxymethylcellulose (CMC). In some embodiments, the polyolefin can include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), co- polymers thereof, and / or mixtures thereof. For example, the binder can include polyvinylene chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethyleneglycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, co- polymers thereof, and / or admixtures thereof. In some embodiments, the binder may be a thermoplastic. In some embodiments, the binder comprises a fibrillizable polymer. In certain embodiments, the binder comprises, consists essentially, or consists of PTFE. In some embodiments, the electrode film comprises, comprises at least, comprises at most 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 binders.

[0074] In some embodiments, the conductive additive may comprise a conductive carbon additive, such as carbon black and / or carbon nanotube. In some embodiments, the electrode film comprises the conductive additive of, of about, of at least, of at least about, of at most, of at most about, 6 wt.%, 5 wt.% 4.5 wt.%, 4wt.%, 3.5 wt.%, 3 wt.%, 2.5 wt.%, 2 wt.%, 1.5 wt.%, 1 wt.%, 0.5 wt.%, or any ranges therebetween, of the electrode film. In some embodiments, the electrode film may not include a conductive additive. Energy Storage Device

[0075] In some embodiments, the energy storage devices include for example, capacitors, batteries, capacitor-battery hybrids and / or fuel cells. Energy storage devices of the present disclosure include an electrolyte, a cathode, an anode, a separator and a housing, wherein the electrolyte, cathode and anode are disposed within the housing. In some embodiments, an energy storage device as provided herein is a lithium-ion battery. Each of the cathode and anode include an electrode film and a current collector that form the electrode. In some embodiments, the energy storage device includes the electrode film formed by the process disclosed herein. The electrode films generally comprise one or more active materials, for example, the lithium iron phosphate as provided herein. EXAMPLES

[0076] Example embodiments of the present disclosure, including processes, materials and / or resultant products, are described in the following examples.Example – Iron Phosphate Preparation with Solvent Evaporation during Reaction 105 g of iron powder material was gradually added to 450 g of water and 225 g of 85% phosphoric acid over one hour, wherein the reaction temperature was kept to a maximum of 80 °C and the elemental ratio of iron to phosphorus was 1:104. The reaction mixture was mixed for a total of four hours. The reaction mixture was then left unstirred 16 hours, after which the reaction was a dry, black, solid / sponge-like material. The material was milled and calcinated at 900 °C – 950 °C for about two hours, forming a composition comprising iron phosphate. Example 2 – Iron Phosphate Preparation by Addition of Iron-Based Material into Solution

[0078] 105 g of iron powder material was added into the solution comprising 225 g of 85% phosphoric acid and 225 g of deionized water, at a rate of about 1 g per minute. The reaction mixture was mixed at 45 °C and the addition of iron powder stopped as soon as the surface of the reaction mixture was covered with foam. The reaction mixture temperature increased to about 65 °C during the reaction. Once the reaction finished, a paste was formed comprising a low water / moisture content of about 25%. The resulting paste was collected and calcinated in air at 800 °C for about two hours, forming a composition comprising iron phosphate. Example 3 – Iron Phosphate Preparation by Addition of Phosphoric Acid into Solution

[0079] 225 g of 85% phosphoric acid was added into the solution comprising 105 g of iron powder material and 225 g of deionized water, at a rate of about 1 g per minute. 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 is covered with foam. The reaction mixture temperature increased to about 65 °C during the reaction. Once the reaction finished, a paste was formed comprising a low water / moisture content of about 25%. The resulting paste was collected and calcinated in air at 800 °C for about two hours, forming a composition comprising iron phosphate.

[0080] FIGS. 7A-7D are images at different stages. FIG. 7A is an image during the reaction. FIG. 7B is an image of the formed paste at the end of the reaction showing thatwater had been substantially evaporated. FIG.7C is an image of the naturally dried and ground paste. FIG.7D is an image of the particles after calcination. Example 4 – XRD Analysis of Iron Phosphate Composition

[0081] The X-ray diffraction (XRD) spectra of the iron phosphate composition prepared in Example 2 was collected and compared to a commercially available iron phosphate. FIG.7E is a representative XRD pattern of the iron phosphate composition, relative to commercially available iron phosphate. As illustrated by FIG. 7E, the iron phosphate composition prepared by the process disclosed herein provided a similar XRD spectra as commercially available iron phosphate.

[0082] FIG. 8A further illustrates the XRD pattern of iron phosphate composition prepared in Example 2, while FIG. 8B illustrates the XRD pattern of commercially available iron phosphate. Again, the iron phosphate composition prepared by the process disclosed herein provided a similar XRD spectra as commercially available iron phosphate. Example 5 – XRD Analysis of Lithium Iron Phosphate Material

[0083] Lithium iron phosphate was prepared with the iron phosphate composition prepared in Example 2. The XRD spectra of the resulting lithium iron phosphate material was collected and compared to a commercially available lithium iron phosphate. FIG. 9A is a representative XRD pattern of the lithium iron phosphate material prepared with the iron phosphate composition prepared in Example 2. FIG. 9B is a representative XRD pattern of commercially available lithium iron phosphate. As illustrated by FIGS.9A and 9B, the lithium iron phosphate material prepared with the iron phosphate composition prepared by the process disclosed herein provided a similar XRD spectra as commercially available lithium iron phosphate. Example 6 – Electrochemical Performance of Coin Cells

[0084] Cathode foils comprising the lithium iron phosphate material described herein were prepared. Respective electrodes were produced and were tested in coin cells. FIG. 10 provides the specific charge and discharge capacity of the cathode foil comprising the lithium iron phosphate material described herein.Example 7 – Purity Level of Iron Phosphate Composition

[0085] Table 1 summarizes the weight percentage 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), by weight percent. Table 1. Summary of Elemental Composition Element Experiment 1 Sample 1 Sample 2 Sample 3 Sample 4 Al 0.002 0.001 0.003 0.003 0.023 Ca 0.007 0.001 0.003 0.004 0.005 Co 0.000 0.000 0.000 0.000 0.000 Cr 0.011 0.001 0.000 0.001 0.009 Cu 0.024 0.000 0.000 0.000 0.000 Fe 38.9 41.1 36.1 38.7 33.1 K 0.003 0.008 0.008 0.005 0.001 Mg 0.001 0.017 0.002 0.002 0.001 Mn 0.045 0.051 0.025 0.006 0.038 Na 0.001 0.002 0.000 0.001 0.003 Ni 0.010 0.003 0.002 0.000 0.001 P 22.2 23.4 20.2 22.8 18.3 Pb 0.001 0.001 0.001 0.001 0.001 S 0.004 0.014 0.001 0.032 0.002 Si 0.003 0.000 0.000 0.001 0.000 Ti 0.000 0.000 0.001 0.001 0.004 Zn 0.003 0.003 0.000 0.002 0.001 Zr 0.001 0.001 0.001 0.001 0.001

[0086] As summarized in Table 1, the purity level of the iron phosphate composition prepared by the process disclosed herein is the same or superior to that of the commercially available iron phosphate samples (Samples 1-4). For example, the iron phosphate composition prepared by the process disclosed herein comprises 0.001 wt.% magnesium, while Sample 1 comprises 0.017 wt.% magnesium. Sample 2 comprises 0.008 wt.% potassium, while the iron phosphate composition prepared by the process disclosed herein comprises 0.003 wt.% potassium. Sample 3 comprises 0.032 wt.% sulfur, while the iron phosphate composition prepared by the process disclosed herein comprises 0.004 wt.%sulfur. In addition, Sample 4 comprises 0.023 wt.% aluminum, while the iron phosphate composition prepared by the process disclosed herein comprises 0.002 wt.% aluminum. Example 8 – Purity Level of Lithium Iron Phosphate Material

[0087] Table 2 summarizes the relative elemental composition of the lithium iron phosphate material described herein, compared to a commercially available lithium iron phosphate sample (Sample 5), by weight percent (i.e., wt.%). Table 2. Summary of Elemental Composition Element Experiment 2 Sample 5 Al 0.005 0.003 As 0.000 0.002 B 0.002 0.000 Ba 0.000 0.000 Ca 0.009 0.003 Cd 0.000 0.000 Co 0.000 0.000 Cr 0.004 0.001 Cu 0.000 0.000 Fe 34.7 38.4 K 0.011 0.013 Li 4.57 4.47 Mg 0.010 0.011 Mn 0.038 0.038 Mo 0.000 0.000 Na 0.005 0.005 Ni 0.004 0.000 P 20 20.4 Pb 0.001 0.001 S 0.011 0.014 Se 0.000 0.000 Si 0.006 0.002 Sr 0.000 0.000 Ti 0.008 0.027 V 0.001 0.001 W 0.000 0.000 Zn 0.005 0.002Element Experiment 2 Sample 5 Zr0.001 0.001

[0088] As summarized in Table 2, the elemental composition of the lithium iron phosphate material prepared by the process disclosed herein was similar to that of commercially available lithium iron phosphate. Example 9 – Iron Phosphate Preparation by Addition of Spherical Iron Particles into Solution

[0089] 1000 g of iron powder material was added into the solution comprising 2075 g of 85% phosphoric acid and 2075 g of deionized water, at a rate of about 1kg per hour in a stir tank reactor. The iron powder has a spherical morphology and a small particle size. The reaction mixture was mixed at 60 °C and the addition of iron powder. The reaction mixture temperature increased to about 90 °C at the maximum during the reaction. The reaction continued with water evaporation for 5 hours. Once the reaction finished, a paste was formed. The resulting paste was collected and dried in ambient air. The dried paste was then hand grinded and then calcinated in air at 800 °C for about two hours in a batch furnace, forming a composition comprising iron phosphate.

[0090] FIGS.11A-11D are images at different stages. FIG.11A is an image during the stir reaction. FIG.11B is an image of the formed paste at the end of the reaction showing that water has been substantially evaporated. FIG. 11C is an image of the dried and grinded particles. FIG. 11D is an image of the particles after calcination. FIG. 12A is an SEM image of the calcinated particles. FIG.12B is an XRD pattern of the calcinated particles. Example 10 – Iron Phosphate Preparation by Addition of Coarse Iron Particles into Solution

[0091] 10 kg of iron powder material was added into the solution comprising 24.3 kg of 75% phosphoric acid, 10 ml defoamer, and 18.7 kg of deionized water, at a rate of about 1kg per hour in a ploughshare mixer. The iron powder materials are coarse iron powders. The reaction mixture was mixed at 85 °C and the addition of iron powder. The mixer was maintained at 85°C for 5 hours for reaction and evaporating the water. Once the reaction finished, a paste was formed. The resulting paste was collected and milled. The dried pastewas then calcinated in air at 840 °C for about 1 hour in a rotary furnace, forming a composition comprising iron phosphate.

[0092] FIGS. 13A-13D are images at different stages. FIGS. 13A and 13B are images of the product after the reaction. FIG. 13C is an image of particles calcinated in a rotary furnace. FIG. 13D is an image of the anhydrous collected particles after calcination. FIG.14 is an XRD pattern of the calcinated particles. Example 11 – Lithium Iron Phosphate Preparation

[0093] 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 the iron in the iron phosphate is 1.04:1. The slurry was bead milled to have a D90 particle distribution less than about 2 μm. The milled slurry was spray dried with an inlet temperature of 220oC and outlet temperature of 110oC to obtain the dried powders. The dried powders were calcinated in nitrogen atmosphere at 760oC for 2 hours. The calcinated product was crushed and grinded to obtain the final lithium iron phosphate particles.

[0094] While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure. Accordingly, the scope of the present inventions is defined only by reference to the appended claims.

[0095] Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at leastsome of such features and / or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0096] Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

[0097] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and / or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others 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 the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. For example, any of the components for an energy storage system described herein can be provided separately,or integrated together (e.g., packaged together, or attached together) to form an energy storage system.

[0098] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0099] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and / or steps are included or are to be performed in any particular embodiment.

[0100] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0101] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount, depending on the desired function or desired result.

[0102] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification oras presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

Claims

1. A process of preparing iron phosphate, comprising: combining an iron-based material, phosphoric acid and a liquid to form a reaction mixture comprising iron phosphate, wherein the molar ratio of the iron-based material to phosphoric acid is about 1:1.5 to 1.5:1; and processing the reaction mixture to form a composition comprising iron phosphate.

2. The process of Claim 1, wherein the iron-based material comprises iron metal.

3. The process of Claim 1 or 2, wherein the iron-based material comprises at least 95% iron.

4. The process of any one of Claims 1-3, wherein the iron-based material comprises iron-based powder particles comprising a D50 particle size distribution of about 1 ^m – ^^^^^m.

5. The process of Claim 4, wherein the iron-based powder particles comprise a spherical morphology.

6. The process of any one of Claims 1-5, wherein the iron-based material comprises iron scrap metal.

7. The process of any one of Claims 1-6, wherein the combining comprises adding the iron-based material into a solution comprising the liquid and phosphoric acid at a rate from about 0.1 g per minute to about 1,000 g per minute.

8. The process of any one of Claims 1-6, wherein the combining comprises adding phosphoric acid into a solution comprising the liquid and the iron-based material at a rate from about 0.1 g per minute to about 1,000 g per minute.

9. The process of any one of Claims 1-8, wherein the processing the reaction mixture comprises heating the reaction mixture to at a temperature in a range of about 500 °C – 1000 °C.

10. The process of any one of Claims 1-9, wherein the processing the reaction mixture comprises at least one of drying, calcination and crushing.

11. The process of any one of Claims 1-10, wherein the composition comprises at least 33 wt.% iron and at least 18 wt.% phosphorus.

12. The process of any one of Claims 1-11, wherein the composition comprises at least 38 wt.% iron and at least 22 wt.% phosphorus.

13. The process of any one of Claims 1-12, wherein the composition comprises less than 0.01 wt.% magnesium 14. The process of any one of Claims 1-13, wherein the composition comprises less than 1 wt.% total impurities.

15. The process of any one of Claims 1-14, wherein the liquid comprises water.

16. The process of any one of Claims 1-15, wherein the reaction mixture comprises an amount of the liquid of at least about 20 wt.%.

17. The process of any one of Claims 1-16, wherein the molar ratio of the iron- based material to phosphoric acid is about 1:1.25 to 1.25:

1.

18. The process of any one of Claims 1-17, further comprising recovering a byproduct.

19. The process of Claim 18, wherein the byproduct comprises a material selected from the group consisting of H2, water, and combinations thereof.

20. A process of preparing lithium iron phosphate, comprising: forming the composition comprising iron phosphate according to the process of any one of Claims 1-19; combining the composition with a lithium source and a carbon source to form a calcination mixture; and calcinating the calcination mixture to form lithium iron phosphate.

21. The process of Claim 20, wherein the combining comprises combining with a liquid to form the calcination mixture.

22. The process of Claim 20 or 21, wherein the process further comprises spray drying the calcination mixture.

23. The process of any one of Claims 20-22, wherein the process further comprises milling the calcination mixture.

24. A process of preparing an electrode film for an energy storage device, comprising: forming the lithium iron phosphate according to the process of any one of Claims 20-23;combining a binder with the lithium iron phosphate to form an electrode film mixture; and processing the electrode film mixture to form an electrode film.

25. The process of Claim 24, wherein the combining the binder with the lithium iron phosphate comprises combining the binder and a conductive carbon with the lithium iron phosphate.

Images