Reagent iron source with defined and reproducible chemical composition and fast kinetics

Abstract

A method for preparing a reactant iron source for preparing a cathode material. The reactant iron source has the general formula FeO1 + x (wherein x varies between 0.046 and 0.195) ("FeO"). The method includes treating a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2) to produce a reactant iron source having a defined and reproducible chemical composition and rapid kinetics.

Description

Technical Field

[0001] This invention generally relates to iron sources of reactants and their use in the preparation of cathode materials. More specifically, this invention relates to iron sources of the general formula FeO. 1+x The reactant iron source, wherein x varies between 0.046 and 0.195 (“FeO”). The reactant iron source (“FeO”) according to the invention has a defined and reproducible chemical composition and rapid kinetics, and can be used as a single iron source for the preparation of cathode materials. Background Technology

[0002] Since lithium iron phosphate (LFP) and its analogue lithium manganese iron phosphate (LMFP) were introduced and recently used as cathode materials for lithium-ion batteries, several synthesis methods have been proposed. These methods rely on the use of a variety of potential iron precursors: Fe3(PO4)2, Fe2O3, Fe2P2O7, FePO4, FeC2O4, and FeSO4·xH2O, among which FePO4 is the most widely used in solid-state processes, initially documented in WO 02 / 27823 and WO 02 / 27824 and now mainly produced in China. Its success is attributed to its apparent simplicity (simultaneous synthesis of LFP and carbon coating) and short residence time, as it allows the slowly diffusing Fe... 3+ and PO4 3- Ions are bound within a single molecule. However, like most other such processes, this solid-state process requires the use of purely chemical precursors, whose synthesis is complex and multi-step, resulting in waste products and / or requiring large amounts of water. This leads to monetary and / or environmental costs (e.g., the emission of waste Na2SO4) that are detrimental to the development of large-scale energy storage and electric transportation, especially in countries with stringent environmental regulations.

[0003] Recently developed high-temperature melt synthesis processes have addressed these issues and are described in the following related patent applications: WO 2005 / 062404 A1, WO 2013 / 177671 A1, and WO 2015 / 179972 A1. The processes described in these applications are significantly less specific to the reactants than previous processes because they proceed at high temperatures in a liquid state, where the reaction is rapid. More importantly, thermodynamic equilibrium can be rapidly achieved under conditions favorable for producing a well-defined LFP composition in the melt and once cooled and solidified.

[0004] The inventions described in these applications offer significant simplification and cost reduction in reactants that can be used as Fe, Li, and PO4 sources. For example, instead of using FePO4 and battery-grade Li2CO3 in solid-state processes to manufacture LFPs as described in WO 02 / 27823 and WO 02 / 27824, it has been shown that LiPO3 or in-situ formed LiPO3 precursors and Fe can be used.0 With Fe2O3 or Fe 0 A simple mixture of Fe3O4 (whose composition is equivalent to FeO) reacts according to the following overall reaction:

[0005] Equation 1

[0006] Such a dual-source Fe is needed because floribundum (FeO) itself is not commercially available, nor is it considered stable at room temperature, nor is it a well-defined composition. Floribundum itself is not a stoichiometric composition because iron is typically defective and exists within the compositional range. In contrast, iron metal (Fe) 0 Hematite (Fe2O3) and, to a certain extent, magnetite (Fe3O4) all have well-defined compositions and are commercially available. LiPO3 can be formed in situ in a melt from Li-containing precursors such as Li2CO3, LiOH, and Li2SO4, and P-containing precursors such as P2O5, H3PO4, HPO3, ammonium monohydrogen phosphate (MAP), and diammonium hydrogen phosphate (DAP), or from Li and P-containing chemicals such as LiH2PO4 and Li3PO4.

[0007] The use of Fe2O3 and Fe3O4 is interesting because these high-purity materials are widely available as pigments or specialty chemicals, and are less expensive and have a smaller environmental impact compared to iron phosphate. Nevertheless, they are relatively expensive relative to iron ores and iron metal. The inventors have previously shown that iron ore concentrates can also be used to manufacture LFP, with the main disadvantage being that contamination by Si (in the form of SiO2) and other residual impurities reduces the reversible capacity of LFP (Talebi et al.). J. Solid State Electrochem. (DOIs 10.1007 / s10008-015-3049-7 and 10.1007 / s10008-016-3324-2). The proposal to use ferrous metal as a partial source of Fe, in conjunction with supplemental Fe2O3 (or Fe3O4), has the advantage that its higher purity stems from the inherent purification of iron and steel (low alloys), which removes SiO2 and other impurities from the mineral gangue into the slag. Ferrous metal is attractive as the sole source of Fe in the molten process of this invention because it is readily available in large quantities, chemically well-defined, has reproducible specifications, and is inexpensive due to its large-scale production. However, for LFP molten synthesis, ferrous metal alone is impractical because an additional oxygen source is required to form LiFePO4. This oxygen can be supplied by a mixture of oxygen-containing gases such as O2, CO2, and H2O, or by supplementary reactants such as Li2CO3 and LiH2PO4 (which release CO2 and H2O, respectively).

[0008] The lack of a reproducible, well-known, widely available, and low-cost iron source for alternative reactant mixtures (iron + iron oxides) stems from the fact that, given the need for an oxygen source, using iron metal as the sole source of both reactant and Fe is currently impractical. Instead, iron ore concentrates used as iron sources carry SiO2 and other impurities from gangue, leading to batch-to-batch compositional variations and, more importantly, inter-mine compositional variations. This also applies to Fe requiring an additional reducing source. +2 / Fe +3 Although these Fe reactants, as shown in WO 02 / 27823 and WO 02 / 27824, can be used with suitable reducing agents, their cost, quality, reproducibility, and ease of use are not optimal for the broad market share development required for electric vehicles and large-scale energy storage.

[0009] A reactant iron source is needed to serve as a single iron source in the preparation of cathode materials. In particular, such an iron source is needed to be efficient, have controlled purity, be cost-effective, and be obtained under environmentally friendly conditions. Summary of the Invention

[0010] The inventor designed, prepared, and used FeO 1+x (where x varies between 0.046 and 0.195) (“FeO”) reactant iron source. The reactant iron source according to the invention has a defined and reproducible chemical composition and rapid kinetics, and is obtained from a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2). The first iron source can be an iron metal, such as soft iron, steel, cast iron, and carbonyl iron (carbonyl iron powder). Alternatively, the first iron source can be purified iron oxide or iron ore.

[0011] In addition, the inventors designed and carried out the preparation of LiFe 1-y M y A method for a cathode material of PO4 (where M is iron or a substituted metal of iron and y varies between 0 and 0.9) or a lithium iron phosphate (LFP) composition or a lithium manganese iron phosphate (LMFP) composition, the method comprising using a reactant iron source (“FeO”) according to the invention with a lithium source and a phosphate source.

[0012] In embodiments of the present invention, the reactant iron source (“FeO”) can be used as a single iron source in the method according to the present invention, which can be a melting method, a semi-melting method, or a solid method.

[0013] In an embodiment of the present invention, the reactant iron source is used in the melting method for preparing cathode materials, and a reaction time of less than about 30 minutes, or less than about 10 minutes, or about 2 minutes is achieved.

[0014] In embodiments of the invention, the cathode material, LFP composition, or LMFP composition is obtained in the form of ingots or broken ingots; optionally, the ingots or broken ingots are further subjected to at least one other process, including micronization, submicronization, or pyrolysis in the presence of a carbon material. These processes can be carried out on-site or at different locations.

[0015] Therefore, the present invention provides the following aspects:

[0016] (1). Used to prepare FeO 1+x A method for producing a reactant iron source (where x varies between 0.046 and 0.195) (“FeO”) includes treating a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2) to produce a reactant iron source, wherein the reactant iron source has a defined and reproducible chemical composition and rapid kinetics.

[0017] (2). The method of (1) above, wherein the first iron source is iron metal, purified iron oxide or iron ore; preferably, the iron metal is soft iron, steel, cast iron or ex-carbonyl iron (carbonyl iron powder).

[0018] (3). Used to prepare FeO 1+x A method for obtaining a reactant iron source (where x varies between 0.046 and 0.195) (“FeO”) includes: subjecting iron metal to an oxidation reaction at a controlled temperature (T) and oxygen partial pressure (pO2) to obtain iron oxides including Fe2O3 or Fe3O4; and subjecting the iron oxides to a reduction reaction at a controlled buffer atmosphere to obtain a reactant iron source; wherein the reactant iron source has a defined and reproducible chemical composition and rapid kinetics.

[0019] (4). The method described in (3) above, wherein the iron metal is soft iron, steel, cast iron or exo-carbonyl iron (carbonyl iron powder).

[0020] (5) The method of any one of (1) to (4) above, wherein the reactant iron source is obtained at a temperature above about 560°C, or 600°C-850°C, or 600°C-1250°C.

[0021] (6) Any of the methods in (1) to (5) above, wherein the oxygen partial pressure pO2 is 1.4 × 10⁻⁶. -25 and 7.0×10 -17 Between atm or 1.4 × 10 -25 and 3.2×10 -9 Between ATM.

[0022] (7). The method of any one of (1) to (6) above, wherein the desired oxygen partial pressure pO2 is achieved by selecting a buffer gas mixture, said buffer gas mixture comprising CO / CO2, H2 / H2O, H2 / O2, CH4 / O2, CH4 / CO2, H2 / CO2, organic compounds suitable for forming a buffer composition by pyrolysis, gasification or combustion; preferably, the buffer gas is pure and / or diluted with an inert gas including argon or nitrogen.

[0023] (8). The method of (2) above, wherein the first iron source comprises particulate material with a particle size between 25 μm and 1 mm in at least one dimension.

[0024] (9) The reactant iron source (“FeO”) obtained by any of the methods defined in (1)-(8) above.

[0025] (10). The general formula is FeO 1+x (where x varies between 0.046 and 0.195) (“FeO”) reactant iron source, which has a defined and reproducible chemical composition and rapid kinetics, wherein the reactant iron source is obtained from a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2).

[0026] (11). The general formula is FeO 1+x (where x varies between 0.046 and 0.195) (“FeO”) reactant iron source, having a defined and reproducible chemical composition and rapid kinetics, wherein the reactant iron source is obtained from iron metal in a two-step process, which includes subjecting the iron metal to oxidation to obtain iron oxide comprising Fe2O3 or Fe3O4, and then reducing the iron oxide under a controlled buffer atmosphere to produce the reactant iron source.

[0027] (12). The iron source of the reactants in (10) above, wherein the first iron source is iron metal, purified iron oxide or iron ore; preferably, the iron metal is soft iron, steel, cast iron or ex-carbonyl iron (carbonyl iron powder).

[0028] (13). The iron source of the reactants in (11) above, wherein the iron metal is soft iron, steel, cast iron or exo-carbonyl iron (carbonyl iron powder).

[0029] (14). Used to prepare LiFe with the general formula LiFe 1-y M y A method for a cathode material consisting of PO4 (where M is a substituted metal of iron and y varies between 0 and 0.9) or a cathode material consisting of lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP), comprising reacting an iron source of reactants defined in any of (1)-(13) above with a lithium source and a phosphate source and optionally a manganese source or a substituted metal M.

[0030] (15). The method described in (14) above, wherein the reactant iron source is used as a single iron source.

[0031] (16). The method described in (14) or (15) above is a melting method, a semi-melting method or a solid method.

[0032] (17). The method described in (14) or (15) above is a melting method.

[0033] (18). The method described in (17) above, wherein the reaction time is less than about 30 minutes, or less than about 10 minutes, or about 2 minutes.

[0034] (19). The method of (17) above, wherein the reaction temperature is between 660°C and 1300°C or between 900°C and 1200°C, and wherein the reaction is carried out in an oxygen-buffered atmosphere; optionally, a cooling step and a solidification step are performed after the reaction to obtain a reactant iron source in the form of ingots or atomized droplets.

[0035] (20) The method of any one of (14)-(19) above, wherein the lithium source is Li2CO3, LiOH, Li2SO4, LiH2PO4, LiPO3, Li3PO4 or a mixture thereof, such as a LiPO3-Li3PO4 mixture; and the phosphate source is P2O5, H3PO4, HPO3, monoammonium hydrogen phosphate (MAP) or diammonium hydrogen phosphate (DAP), or related chemicals, including LiH2PO4, LiPO3, Li3PO4 and a mixture thereof, such as a LiPO3-Li3PO4 mixture.

[0036] (21). The method of any one of (14)-(20) above, wherein the cathode material is obtained in the form of an ingot or a broken ingot; optionally, the ingot or the broken ingot is further subjected to at least one other process, including micronization, to obtain a homogeneous granulated powder; optionally, the homogeneous granulated powder is further subjected to submicronization by dry milling, wet milling or jet milling to obtain a submicronized powder; optionally, the submicronized powder is further subjected to pyrolysis in the presence of at least one carbon source to obtain an electrochemically active cathode material.

[0037] (22). The method of any one of (14)-(21) above, wherein the cathode material has an olivine structure.

[0038] (23). The reactant iron source (“FeO”) as defined in any of (9)-(13) above is used to prepare the general formula LiFe 1-y M y In methods for preparing cathode materials of PO4, where M is iron or a metal substituted with iron and y varies between 0 and 0.9, or in methods for preparing lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP) compositions.

[0039] (24). The reactant iron source (“FeO”) as defined in any of (9)-(13) above is used in the preparation of general formula LiFe 1- y M y Use in methods of producing cathode materials of PO4, wherein M is iron or a metal substituted for iron and y varies between 0 and 0.9, or in methods of preparing lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP) compositions.

[0040] (25). Cathode material obtained by any of the methods defined in (14)-(22) above.

[0041] (26). A battery having a cathode comprising a material obtained by any of the methods defined in (14)-(22) above.

[0042] (27). A battery manufacturer that implements the methods defined in any one of (1)-(8) and (14)-(22) above.

[0043] Other objects, advantages and features of the invention will become more apparent after reading the following non-limiting description of specific embodiments thereof, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0044] The patent or application documents contain at least one color drawing. Upon request and payment of the necessary fees, the International Bureau will provide a copy of the patent or patent application publication with the color drawing.

[0045] In the attached diagram:

[0046] Figure 1 : A phase diagram showing the stability regions of single-phase FeO ("FeO") compositions. Presented below. Figure 2-5 The region of interest used is located within the dashed box. (Adapted from: Li et al., Metals & Corrosion, DOI:10.1007 / s10853-019-04027-0).

[0047] Figure 2 : Stability windows for the Floatite phase for various oxygen partial pressures. Combinations of temperature and oxygen partial pressure can be selected to produce O / Fe content (derived from FACTSage) within the "FeO" phase domain; specific boundary values ​​are shown in Table 2.

[0048] Figure 3: The Floatate phase stability window as a function of temperature for various CO / CO2 buffer gas mixture compositions. Gas mixtures and temperature impart effective oxygen partial pressures. In the absence of dilution, the Budoal effect limits applicability below 700°C (derived by FACTSage).

[0049] Figure 4 : The Floatite phase stability window as a function of temperature for various CO / CO2 buffer gas mixture compositions (diluted with an inert gas). Diluting the gas mixture with an inert gas can mitigate the Budoal effect (derived from FACTSage).

[0050] Figure 5 : The temperature-dependent window of the Floatite phase stability for various H2 / H2O buffer gas mixture compositions. H2 / H2O avoids the Budoal effect (derived from FACTSage).

[0051] Figure 6 TGA signals of a reference substance undergoing the conversion from Fe2O3 to FeO at 750°C under equimolar CO / CO2 buffer conditions and without conversion under N2 atmosphere.

[0052] Figure 7 Typical XRD pattern after heat treatment at 900℃ in a CO / CO2 buffer gas mixture. The FeO phase is predominantly observed, accompanied by some Fe3O4. The initial Fe2O3 phase is no longer visible.

[0053] Figure 8 XRD pattern of FeO material in Example 7 after a 2-minute reaction time in a hot bath.

[0054] Figure 9 XRD pattern of the material from Example 8, which uses carbonyl iron powder (CIP) as an iron source supplied to a hot pool of LiPO3. Detailed Implementation

[0055] Before further describing the invention, it should be understood that the invention is not limited to the specific embodiments described below, as variations of these embodiments can be made and still fall within the scope of the appended claims. It should also be understood that the terminology used is for the purpose of describing particular embodiments and is not intended to be limiting. Rather, the scope of the invention will be determined by the appended claims.

[0056] To provide a clear and consistent understanding of the terminology used herein, numerous definitions are provided below. Furthermore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0057] When used with the term "comprising" in the claims and / or specification, the use of the words "a" or "an" can mean "one," but is consistent with "one or more," "at least one," and "more than one." Similarly, the word "another" can mean at least a second or more.

[0058] As used in this specification and claims, the terms “comprising” (and any form of “comprising”, such as “comprise” and “comprises”), “having” (and any form of “having”, such as “have” and “has”), “including” (and any form of “including”, such as “include” and “includes”), or “containing” (and any form of “containing”, such as “contain” and “contains”) are inclusive or open-ended and do not exclude additional undescribed elements or process steps.

[0059] As used herein, the term "FeO" refers to the reactant iron source according to the present invention. It has the general formula FeO 1+x , where x varies between 0.046 and 0.195. Furthermore, it has a defined and reproducible chemical composition and rapid kinetics. The reactant iron source according to the invention is obtained by a method comprising treating a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2). The first iron source can be iron metal, purified iron oxide, or iron ore. And this iron source can be soft iron, steel, cast iron, or exo-carbonyl iron (carbonyl iron powder). The reactant according to the invention can be used particularly in melting processes to prepare cathode materials, wherein the reaction time is less than about 30 minutes, or less than about 10 minutes.

[0060] As used herein, the terms "ex-carbonyl iron" or "carbonyl iron powder (CIP)" refer to iron metal obtained from a carbonyl deposition process (i.e., thermal decomposition of a metal carbonyl compound). This particulate iron exhibits high purity. The reactant iron source according to the invention can be obtained using carbonyl iron. In embodiments of the invention, carbonyl iron is oxidized to iron oxides such as "FeO", or alternatively as Fe2O3 and Fe3O4, which are further reduced to obtain the reactant iron source "FeO".

[0061] This invention benefits from the production and use of a single-source Fe reactant as 'FeO' with a well-defined composition obtained from iron metal, in embodiments of the invention, because soft iron, steel, and cast iron are currently produced in large quantities from several iron minerals (magnetite, hematite, ilmenite, etc.) and even from recycled scrap iron. Furthermore, new processes are being developed to produce green iron by replacing fossil fuels with renewable hydrogen or ammonia, which can also be converted according to the invention to similarly produce green 'FeO' reactants. Although iron oxides (e.g., Fe₂O₃, Fe₃O₄) have been demonstrated in molten processes, these processes use C, CO / CO₂, or H₂ / H₂O reducing agents to fix Fe. +2 Oxidized state, or alternatively, Fe. 0 As a reducing agent and supplementary iron source in combination, for example, as (Fe 0 A mixture of Fe₂O₃ and Fe₂O₃ was used, which serves as the chemical equivalent of the FeO source according to Equation 1 above. This solution was found to rapidly form LiFePO₄ in the melt, but some drawbacks remain: the pure and well-defined Fe₂O₃ chemical reactants are relatively expensive, and more importantly, Fe… 0 Specific gravity (7.8 g / cm³) 3 The specific gravity of Fe is much higher than that of Fe₂O₃ powder or LiFePO₄ melt. We observed that Fe 0 There is a tendency for settling after the melt is added, with iron quickly found at the bottom of the crucible, where it may sinter into larger, slower-reacting lumps. Although this can be mitigated by stirring the melt, both chemicals may gradually aggregate or react with the graphite crucible. Depending on the melt temperature and composition, for example, carbon from the graphite container can react with Fe. 0 Competition as a reducing agent for Fe2O3 and the need to consider adjusting Fe 0 and Fe 3+ When the source is present, unreacted Fe2O3 then contributes to reducing the lifespan of the graphite crucible.

[0062] For these reasons, the present invention has a higher Fe content than Fe 0 A single iron source in the form of 'FeO' with a low specific gravity and a well-defined composition is particularly attractive for melting processes. Non-stoichiometric 'FeO' is known to exist at high temperatures, but is therefore not considered stable at ambient temperatures. Furthermore, its variable composition is considered unfavorable as a reliable chemical reactant.

[0063] However, this invention defines the specific experimental conditions required to form 'FeO', which is useful as a single iron reactant source for the melting process of this invention. The instability of floppy at ambient temperature does not affect the overall Fe / O ratio required to form stoichiometric LiFePO4 at a specific temperature. The use of a buffer gas atmosphere during synthesis corrects for 'FeO' floppy relative to pure Fe according to Equation 2 outlined below. 2+ Slight deviations in composition, in which LiPO3 can be alternatively formed in situ from reactants containing Li and P.

[0064] Equation 2

[0065] Apart from a slight correction to the 1:1 Fe / O ratio from the buffer atmosphere, the simplicity of the reaction, which requires no additional redox reactants, allows for rapid residence times to form LiFePO4 in less than 30 minutes, even less than 10 minutes, and even less than 2 minutes, thereby improving productivity and the lifespan of graphite crucibles.

[0066] In embodiments of the invention, the 'FeO' single reactant is produced from widely available, low-cost, high-purity iron, preferably in particulate form and with reproducible specifications, through controlled oxidation as described below. As an example, low-carbon or cast iron powders, typically with particle sizes in the range of 50 to 700 μm, can be used to form 'FeO' as a reactant for LiFePO4. Atomized iron, such as Atomet from Quebec metal powder QMP (now Rio Tinto), is particularly convenient for producing 'FeO' reactants with defined and reproducible compositions that can be used directly as the sole source of Fe (close to Fe). +2 This is particularly suitable for melting processes, and therefore benefits from known iron purification processes that result in low-C or cast iron powder, especially for low SiO2 concentrations and other related elements. The compositions of two typical grades, Atomet 1001HP (reduced iron) and Atomet 56 (cast iron), are summarized in Table 1 below.

[0067] Table 1. Atomet and concentrated / purified iron oxide references and major impurities present.

[0068]

[0069] To achieve the conversion of iron powder into flosite 'FeO' with a reproducible known composition, the metal powder is subjected to controlled oxidation. Buffer gas mixtures such as CO / CO2, H2 / H2O, CH4 / O2, and CH4 / CO2 (biogas) are preferably used, with H2 / H2O preferably used at a temperature between about 563°C and 1363°C, and the composition determined by thermodynamic calculations under equilibrium conditions as shown in the examples below. The preferred flosite composition of the present invention is FeO. (1+x) Where x changes from 0.046 to 0.195, this is due to the use of Fe 0 The conversion to a well-defined and known floatite composition, termed 'FeO,' is limited by temperature and pO2 atmosphere. Of these compositions, iron-rich compositions are more attractive due to their closer approximation to a 1:1 stoichiometric ratio. Table 2 below summarizes the compositions that can be prepared under equilibrium conditions at different temperatures and pO2 to obtain the desired 'FeO' reactants for melt synthesis. Fluidization, stirring (e.g., rotary kilns), fixed-bed reactors, and enclosed solid reactors, known to those skilled in the art, can be used to achieve rapid conversion equilibrium.

[0070] Table 2. Experimental parameters for temperature and oxygen partial pressure limits to obtain a single 'FeO' phase with known and reproducible stoichiometric ratios.

[0071]

[0072] Depending on the kinetic rate of cooling, flostenite (which is thermodynamically unstable below 563°C) may decompose into a mixture of iron forms, as summarized below:

[0073] Equation 3

[0074] Surprisingly, however, these transformations do not affect the values ​​of the 'FeO' iron reactants of the present invention, because the overall chemical composition obtained at room temperature remains unchanged regardless of the degree of transformation, and the amounts of iron and oxygen in each solid particle, as defined at high temperature and pO2, remain unchanged and are equivalent to the 'FeO' flourishing composition under LFP melt synthesis conditions as shown in Equation 1.

[0075] Another implementation of the invention is to obtain the 'FeO' reactants from a mine source, such as previously concentrated and purified magnetite or flocculation, especially, but not limited to, the removal of SiO2, a major impurity in most iron concentrates. This is important because, although iron metal is widely available and inexpensive to form 'FeO', alternative iron mine sources can further reduce the conversion steps required through the iron metal and can provide a large quantity of iron that can be used to manufacture 'FeO' according to the invention. This is a significant advantage considering the currently anticipated large market for LFP and LFMP cathode powders, which currently exceeds one million tons annually and is growing.

[0076] In an embodiment of the present invention, Fe is used. 0 Fine particulate form, such as atomized form. In other embodiments of the invention, particulate iron can be obtained via a carbonyl deposition process (i.e., thermal decomposition of a metal carbonyl compound). This particulate iron has a high level of purity and, despite its higher production cost, remains within the scope of this invention. In further embodiments of the invention, other forms and shapes of particulate iron are considered. For example, at least one sheet or needle-like object with a size less than 1 mm can be used to produce a well-defined “FeO” because its size can be reduced before use in LFP synthesis.

[0077] The T and pO2 parameters given in Table 2 are applicable to determining the required “FeO” composition at equilibrium. x and Fe 0 As a starting material. In embodiments of the present invention, two preferred methods for forming "FeO" and their use in the melt synthesis of LiFePO4 are represented by the following Equation 4:

[0078] Equation 4

[0079] In an embodiment of the present invention, iron metal can be first completely oxidized to FeO. x (Fe2O3 and / or Fe3O4), and then FeO under a controlled buffer atmosphere. x The first part of Equation 4 is performed in two steps, reducing it to "FeO".

[0080] As illustrated in the embodiments of the invention described below, particulate iron powder or purified low-SiO2 iron minerals are particularly well-suited for the rapid equilibrium kinetics of a buffer gas composition to produce “FeO”, resulting in easily dispersed and molten particulate single Fe reactants. This is consistent with the previously described equivalent (FeO) 0 +FeO x This is a significant improvement compared to mixtures, which are due to the high density of iron metal particles. (7.87 g / cc) Iron tends to separate in the melt, with the iron particles accumulating at the bottom of the crucible and sintering into lumps. This separated iron mixes and reacts more slowly and tends to form localized Fe-C chemicals with the crucible material, while unreacted Fe2O3 may gradually consume the graphite crucible. Not only is the density of floppyite lower... 5.7g / cc) and closer to the average melt density 2.75 g / cc, and it is known that floatite is Fe +2 Ions are also electronic conductors, allowing for rapid oxide growth, diffusion, and reaction in both liquid and solid states. Although these properties of the reactant "FeO" according to the invention are used in melt processes, they can also be used in other variant synthesis processes involving, for example, "solid-state" or "semi-molten" reactions. This is also represented by Equations 2 and 4, since LiPO3 melts at approximately 650°C, while unreacted stearite remains solid above 1300°C. In embodiments of the invention, other P and Li sources besides the "FeO" of the invention can be used instead of LiPO3.

[0081] Although the use of “FeO” reactant is described primarily in the case of LiFePO4 synthesis in this specification, the invention also includes its use as a reactant for the formation of other iron-containing olivine structures, including LFMP (where M is, for example, Mn) or other LFP and LFMP substituted or doped by other elements through this melting process.

[0082] In embodiments of the present invention, the lithium source is Li2CO3, LiOH, Li2SO4, LiH2PO4, LiPO3, Li3PO4 or a mixture thereof, such as a LiPO3-Li3PO4 mixture; and the phosphate source is P2O5, H3PO4, HPO3, ammonium monohydrogen phosphate (MAP) or dihydrogen phosphate (DAP), or related chemicals, including LiH2PO4, LiPO3, Li3PO4 and mixtures thereof, such as a LiPO3-Li3PO4 mixture.

[0083] According to the present invention, an iron source 'FeO' is prepared as a reactant, and its iron-containing composition includes well-known LFP and LFMP. Applications of olivine structure in synthesis

[0084] Table 2 above allows for the selection of oxygen partial pressures at different temperatures that respect the pO2 constraint for the formation of single-phase “FeO” flourite with well-defined and reproducible stoichiometry, while avoiding a second Fe 0 Or Fe3O4 spinel phase. Figure 1The phase diagram illustrates the stability domain of single-phase "FeO" float. Particulate iron metal powder or purified iron oxide, preferably from iron ore, is used as the starting material because it is more conducive to rapid reaction and equilibrium with the buffer gas. Fluidization, stirring, or a high-surface-area thin fixed bed is advantageously used to rapidly form the desired "FeO".

[0085] Using particulate iron metal obtained by melt atomization, such as Atomet 1001HP from Québec Iron Powder (now Rio Tinto) or cast iron, such as Atomet 56, and low-silica purified iron oxides, such as IronOre Canada (now Rio Tinto), to illustrate the synthesis of “FeO” from metals and oxides to result in a well-defined “FeO”. Both the metal and oxide powders are widely available from the steelmaking industry and have reproducible compositions, as required for large-scale production of LFP, LFMP (> million tons / year) for electric transport and energy storage by 2022. Table 1 above lists the two types and purities of Atomet powders and the concentrated / purified iron minerals used to illustrate the invention.

[0086] In an embodiment of the invention, the Fe-containing... 0 or Fe +3 The iron precursor is used to obtain a well-defined and reproducible 'FeO' reactant, preferably at a temperature between about 563°C and 1363°C, more preferably between about 650°C and 1100°C. For example... Figure 2 As shown, depending on temperature and oxygen partial pressure pO2, different stoichiometric ratios of iron ore can be fixed because of the flostenite FeO (1+x)This is not a stoichiometric composition. For example, at 750°C, x varies from 0.05 to 0.11. The data represented in these figures were generated by the FACTSage program (FactSage 8.2, https: / / www.factsage.com, using an internal database optimized for LFP) and experimentally verified through the examples below. Table 2 above lists the pO2 values ​​that should be fixed to obtain the desired 'FeO', but in practice, this low oxygen partial pressure must be fixed by the buffer gas composition currently used in the steel industry (as commonly represented in the well-known Ellingham diagram). In practice, control of the oxygen partial pressure at a given temperature is obtained by using buffer gas compositions (ratios) such as CO / CO2, H2 / H2O, or by generating a buffer of reactive gas mixtures such as H2 / O2, CH4 / O2, CH4 / CO2, preferably H2 / CO2, which is essential for obtaining flounder with the desired composition according to the present invention. In the case of a buffer that produces a reactant gas mixture, kinetics can benefit from the use of a catalyst (e.g., an oxidation or water-gas shift catalyst) to rapidly achieve the desired buffer gas composition. Diluting the mixture with an inert gas such as Ar or N2 may also be desirable to shift / mitigate the Budoal (C formation) and / or Sabatier (CH4 formation) reactions, which would otherwise limit the effectiveness of the gas mixture in the lower range of the temperature window.

[0087] Figure 3 , Figure 4 and Figure 5 It uses a buffer gas mixture ratio to generate an oxygen partial pressure level at a given temperature, thereby resulting in a specific 'FeO' composition. Figure 2 The implementation of the data in Table 2. Similar gas ratio calculations can be developed for other gases and reactant gas mixtures. Although this invention can potentially be used to achieve the well-defined 'FeO', in the synthesis of LFP (Fe 2+ In the context of ), the O / Fe ratio should be chosen to be close to the floatite-Fe boundary, but still within the floatite region, in order to reduce the degree of reduction required during LFP synthesis (Equation 4).

[0088] The advantages of using a single 'FeO' iron source as described in this invention are the benefit of high iron reactant purity, availability, and ease of dispersion in the melt, as well as a shorter reaction time to form LFP, since both the reactants and the final product have the same Fe content. +2Oxidation state. The following examples demonstrate that reaction times as short as 2 minutes are possible to form LFMP compositions using the 'FeO' reactants of the present invention. Furthermore, an additional advantage of forming LiFePO4 according to Formulas 2 and 4 is the avoidance of gas formation that could lead to foaming, thus allowing for rapid reaction and equilibrium at higher reactant introduction rates. Only small amounts of buffer gas mixtures are used in such synthesis processes to fine-tune the LFP stoichiometry or correct for any unexpected Fe... +2 Oxidation or reduction, as taught in WO 2015 / 179972 A1.

[0089] In embodiments of the invention, the iron precursor used to produce 'FeO' is in particulate form (e.g., low-carbon or cast iron powder or purified FeO). x The preferred iron source is the 'FeO' mineral, which optimizes the conversion and equilibrium rate, and also because of the ease of dispersion of the 'FeO' reactant in the molten pool, as used in WO 2013 / 177671 A1. All these iron sources are widely available from metal powder metallurgy and have reproducible compositions, and can be produced without the chemical waste (e.g., FePO4 and its Na2SO4 waste and wastewater) associated with the production of this iron source. Limiting the number of chemical steps and the accumulation of chemical waste is a significant advantage of this invention for large-scale production.

[0090] When using iron ore to form high-purity 'FeO' reactants, it is important to limit the concentration of impurities such as Si, Mg, Ca, and Al. These residues from gangue can be reduced through mineral concentration and purification via optimized steelmaking processes, as shown in Table 1 above. For example, in Talebi et al., J. Solid State Electrochem., DOI 10.1007 / s10008-015-3049-7 and 10.1007 / s10008-016-3324-2, it was found that in the total Fe source... 0.15 wt% Si (or 0.32% SiO2) is acceptable and has no / low impact on the reversible capacity of the LFP cathode. Total Fe source 1.5 wt% Si (or 3.3 wt% SiO2) results in a 3-10 mAh / g reduction in the reversible capacity of the cathode. In the latter case, the improvement is achieved by adjusting the LFP stoichiometric excess (Li and P) to displace contaminants to the grain boundaries.

[0091] Not only can the process of the present invention be carbon-free, using H2 / H2O and green electricity, and have little waste and few conversion steps (using iron or iron ore directly), but it can also use iron ore or iron metal processed without using carbon or fossil fuels as reducing agents, such as from hydrogen or ammonia, which can be used at any time to prepare the green iron precursor for LFP.

[0092] The 'FeO' reactant according to the present invention can not only ensure a wide supply of iron from green sources but also simplify the process operation because, as shown in the above reaction (Equation 2), only two reactants with known compositions are needed to fix the melt stoichiometry and the overall composition of the solid olivine to be obtained after cooling. Another advantage of the particulate 'FeO' reactant according to the present invention is its ease of dispersion in the melt. In addition, no redox reaction needs to occur because the iron is already close to the +2 oxidation state, like the LFP final product. Under such conditions, only a buffer gas mixture needs to be used above the melt during LFP synthesis to control the local pO2 to fine-tune the LiFePO4 melt composition and stoichiometry and avoid any accidental Fe +2 oxidation or reduction. This is particularly advantageous for rapid LiFePO4 formation and equilibrium.

[0093] The melt synthesis used to illustrate the interest of the 'FeO' precursor of the present invention is merely a preferred mode of implementation. It is not restrictive because other synthesis routes, such as solid-state or semi-molten, can also benefit from the advantageous properties of 'FeO'. This also applies to other Li and P sources that can be used to replace or in-situ form LiPO3, such as Li2CO3, P2O5, Li3PO4, etc.

[0094] The iron precursor of the present invention and its use for olivine phosphate melt synthesis are mainly illustrated by the known compositions of LFP and LFMP, but those skilled in the art will readily understand that the versatility of the melt process can also be used to prepare similar compositions based on the olivine structure. Such analogues are generally represented as Li a Fe 1-x M x P b-y X y O z where: 0.9 < a < 1.1, 0.9 < b < 1.1, 0 < x < 0.9, y < 0.25, 3 < z < 5, M is at least one other fixed-valence or heterovalent metal cation that partially replaces Fe in the olivine structure, and X is at least one other fixed-valence or heterovalent oxygen anion that partially replaces P in the olivine structure, with the overall substitution respecting the principle of electrical neutrality.

[0095] Examples of different compositions and simplified synthesis conditions are described to illustrate different non-limiting embodiments of the invention. Although variations are possible, they still include the key elements of the invention.

[0096] Example

[0097] The following examples are typically used to illustrate how to calculate and select from Fe 0 and FeO x The conditions for synthesizing 'FeO' from the reactants are anticipated, and several modes are used to synthesize LFP and LFMP ingots, and optionally convert them into C-LFP or C-LFMP powders. Fluidized beds have been chosen for the production of 'FeO', but as those skilled in the art will understand, it is by no means the only technology available in industry to achieve the same purpose.

[0098] Apart from using a novel single-phase 'FeO' reactant to simplify and optimize the LFP-LFMP synthesis, the other Li-P reactants used for synthesis and the synthesis conditions of the examples are similar to those described in the same family of patent applications mentioned above, namely WO 2005 / 062404 A1, WO 2013 / 177671 A1 and WO 2015 / 179972 A1.

[0099] Although granular Fe is preferred 0 or FeO x However, other shapes of starting materials are considered, particularly those with at least one needle or flake smaller than 1 mm. In these cases, the formed 'FeO' can be ground to facilitate its reaction and mixing in the melt synthesis of LFP or LFMP.

[0100] Furthermore, in order to minimize the degree of reduction required when using 'FeO' which is slightly richer in O than true FeO, implementation of the present invention will benefit from selecting a 'FeO' composition close to the floostite / floostite-Fe boundary, while remaining within the floostite region of the figure, thereby achieving a near-FeO composition. 2+ It is composed of 'FeO'.

[0101] Example 1

[0102] To reduce the risk of particle agglomeration, a fluidized bed synthesis of 'FeO' was employed. The fluidized bed consisted of a dense bed zone of 15 mm inner diameter × 20 cm length extending to an expanded section of 30 mm inner diameter × 15 cm length to limit particle entrainment. The 15 mm section had a fritted disk fixed to the tube, serving as a gas distributor. The fluidized bed was installed in an electrically heated vertical tube furnace capable of reaching temperatures up to 1200 °C. Insulation material was installed on the tube section extending beyond the furnace. The tube was installed such that the fritted disk distributor was aligned with the bottom of the furnace heating zone. A Fe source sufficient to achieve an initial bed height of 20-30 mm was added to the cooling system. An inert gas (Ar or N2) was introduced into the fluidized bed at a sufficient rate to achieve an apparent gas velocity of 0.3 m / s in the 15 mm section at the target processing temperature. The inert-purged fluidized bed was then heated. When the holding temperature was reached, the inert gas was replaced with a CO / CO2 mixture adjusted to the same apparent velocity. The system was allowed to operate at this temperature and gas mixture composition for 4 hours. After the holding time was reached, the gas mixture was replaced with an inert gas (Ar or N2) to prevent further reaction during cooling. The three feedstock chemicals used to form 'FeO' are summarized in Table 1 above.

[0103] Example 1a: Synthesis of 'FeO' from low-carbon Atomet 1001 HP

[0104] Use Table 2 above and Figure 3 Following the teachings, a temperature of 775 °C and pO2 (using CO / CO2 at a ratio of 1.5 mol / mol) were fixed to obtain 'FeO' with an O / Fe stoichiometric ratio of 1.06. XRD and, more importantly, Fe analysis confirmed the float phase and the predicted stoichiometric ratio.

[0105] Example 1b: Synthesis of 'FeO' from cast iron Atomet 56

[0106] Using the same parameters as in Example 1a and with similar results, this example confirms the equilibrium obtained under these conditions, where the initially present residual carbon is oxidized.

[0107] Example 1c: Synthesis of 'FeO' from IOP low silica concentrate (Iron Ore Canada)

[0108] Starting with oxides, the same parameters as in Examples 1a and 1b were used with similar results. This example confirms the equilibrium conditions reached during the treatment, as the predicted 'FeO' floatite composition was obtained regardless of the initial iron oxide state.

[0109] Example 2: Synthesis of LiFePO4 from 'FeO' in Example 1a

[0110] Using 'FeO' and LiPO3 from Example 1a, LiFePO4 synthesis was achieved starting from a molten LiPO3 pool. Granulated 'FeO' powder from Example 1a was added to molten LiPO3 heated to 1050°C, which was held in a graphite crucible under a 'controlled' pO2 (fixed with CO / CO2) gas mixture. Upon casting and solidification of the melt, pure LiFePO4 ingots with an olivine structure were confirmed, which can be produced and sold as such, or converted into ready-to-use C-LFP cathode powder by grinding and coating.

[0111] Example 3: Synthesis of a typical LFMP composition from 'FeO' in Example 1a

[0112] The same experimental conditions as in Example 2 were used, except that a calculated amount of MnCO3 was added to the molten reaction tank to form LiFe. 0.25 Mn 0.75 PO4.

[0113] Example 4: Synthesis of LiFePO4 in a 'semi-molten state' from 'FeO' in Example 1a

[0114] Using 'FeO' and LiPO3 from Example 1a, LiFePO4 was synthesized starting with a solid stoichiometric mixture of finely dispersed powders of 'FeO' and LiPO3. This solid stoichiometric mixture was placed in a graphite crucible and heated and maintained at 825°C for 5 hours, while being kept under a controlled pO2 (fixed with CO / CO2) gas mixture. After cooling, the homogeneous ingot was milled and XRD analysis was performed to confirm the structure and purity of the LiFePO4 produced by this hybrid synthesis route.

[0115] Example 5: TGA Verification

[0116] In this example, a commercially available Fe2O3 source was used in the TGA: Remuriate ARO (acid regenerated oxide) with a particle size of less than 45 μm.

[0117] The powder was heated to 750°C under a nitrogen stream at 10°C / min and held there for 5 minutes. Then, an equimolar mixture of CO / CO2 was purged at 25 mL / min for 30 minutes instead of the nitrogen stream. After this period, the nitrogen stream was purged again with nitrogen instead of the CO / CO2 mixture. The mixture was held for 5 minutes initially, then cooled to room temperature at 10°C / min. The weight change of the sample was measured using a TGA.

[0118] Figure 6The TGA measurements over time are shown, compared with the same powder exposed to the same heating program but entirely under a N2 atmosphere. A weight loss of 8.6% was determined, corresponding to the transformation from Fe2O3 to FeO floatite. Under these conditions, the transformation occurred within 20 minutes.

[0119] Example 6: Experimental data on FeO conversion

[0120] Similar to Example 5, but using a fluidized bed and approximately 10 g of Fe₂O₃ precursor, FeO magnetite was prepared using a CO / CO₂ mixture. After heating, a nitrogen stream was maintained for 90 minutes to ensure uniform powder temperature, while the CO / CO₂ mixture was purged for 1 hour. The powder was then purged with N₂ again during cooling.

[0121] The cold powder was recovered, weighed, and analyzed by XRD. Figure 7 The typical pattern of the powder after FeO conversion is shown. No Fe2O3 phase is visible. Instead, the FeO phase is predominantly found, along with Fe3O4, which likely originates from the expected disproportionation of FeO into a mixture of Fe3O4 and Fe upon cooling.

[0122] Table 3 below summarizes the weight ratios based on thermal and atmospheric conditions. At 900 °C, the weight of the final product is consistent with expectations based on thermodynamic calculations. In contrast, at 700 °C, kinetic constraints prevented rapid FeO conversion.

[0123] Table 3. Experimental conditions for FeO conversion of Fe2O3 precursor.

[0124]

[0125] Example 7: Reaction kinetics of LFMP synthesis using FeO from the example as the starting iron source

[0126] This embodiment uses the composition of LiFeMnPO4 measured by lattice parameters to illustrate the unusually rapid kinetics of the molten reaction pool.

[0127] 34.25 g of LiH₂PO₄ and 27.5 g of MnCO₃ were placed in a graphite crucible without a graphite cap and maintained at 1100 °C to produce a molten pool of LiMnPO₄ + 25% excess LiPO₃. Once the mixture was completely liquefied, 5.75 g of “FeO”, prepared as in Example 6 at 900 °C with a 1.5% CO / CO₂ gas mixture, was added to the hot pool and held in the crucible without stirring. The added iron is to produce LiFe in the liquid melt. 0.25 Mn 0.75The necessary amount of PO4 was determined for the overall composition. Two minutes after adding FeO, the melt was cast and solidified. After solidification, the ingot was milled to a particle size of less than 75 μm and analyzed by XRD. Figure 8 Analysis revealed a pure olivine material without any trace of Fe impurities (i.e., Fe, FeO, Fe3O4, and Fe2O3). Rietveld refinement analysis of the lattice parameters indicated the formation of pure LiFe. 0.25 Mn 0.75 The presence of the PO4 phase indicates that Fe has intercalated into the resulting olivine material. This example demonstrates the feasibility of using the FeO flochite precursor and the rapid reaction kinetics.

[0128] This needs to be compared with existing solid-state processes that take into account slower diffusion kinetics in the solid phase and residence times of several hours.

[0129] Example 8: Preparation of high-purity LFP using FeO floatite from Fe (carbonyl)

[0130] The procedure in this embodiment is similar to the hot-feed in Example 7, but the starting material is high-purity carbonyl iron powder (CIP) from a commercial source: American Carbonyl, with a particle size of less than 10 μm, and the purpose is to prepare LFP. Here, the CIP is first oxidized to a composition close to Fe2O3 before controlled oxidation at 900°C under CO / CO2. This oxidation step mitigates the risk of CIP agglomeration in the fluidized bed apparatus. Oxidation is performed by feeding 10 g of CIP over 30 minutes using a vibrating feeder and passing it through an upward airflow in a vertical tube furnace maintained at 1000°C. Therefore, 12.9 g of oxidized powder is collected.

[0131] The oxidized powder was converted to "FeO" at 900°C using a CO / CO2 ratio of 1.5, as in Example 6. It should be noted that direct, controlled oxidation of CIP is possible in limited aggregate structures, such as using a rotary kiln or circulating fluidized bed.

[0132] 8.7 g of LiH₂PO₄ was then heated to 800 °C in a graphite crucible to generate a LiPO₃ pool. 6 g of FeO carbonyl groups were then introduced into the molten LiPO₃ pool, and the crucible was further heated to 1100 °C and held at this temperature for 30 minutes. The melt was then cast and solidified into ingots. The ingots were ground until the particle size was below 75 μm for XRD analysis. Figure 9 The XRD pattern is shown, and it shows 100% pure LFP phase without any Fe impurities.

[0133] As those skilled in the art will understand, other variations and combinations can be made to the various embodiments of the invention described above.

[0134] Although this disclosure has been described with reference to specific embodiments, it should be understood that further modifications may be made, and this application is intended to cover any changes, uses or adaptations, including such deviations from this disclosure that fall within the scope of what is known or customary in the art and can be applied to the essential features described herein and as set forth in the appended claims.

[0135] Features described in the context of individual aspects and embodiments of the invention may be used together and / or interchanged. Similarly, features described in the context of a single embodiment may also be provided individually or in any suitable sub-combination.

[0136] This manual references numerous documents, all of which are incorporated herein by reference in their entirety.

[0137] The scope of the claims should not be limited to the preferred embodiments described above; rather, it should be given the broadest interpretation consistent with the entire specification.

Claims

1. A method for preparing FeO 1+x A method for producing a reactant iron source ("FeO"), wherein x varies between 0.046 and 0.195, the method comprising treating a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2) to produce the reactant iron source, wherein the reactant iron source has a defined and reproducible chemical composition and rapid kinetics.

2. The method according to claim 1, wherein the first iron source is iron metal, purified iron oxide, or iron ore. Preferably, the ferrous metal is soft iron, steel, cast iron, or exo-carbonyl iron (carbonyl iron powder).

3. A method for preparing FeO 1+x A method for a reactant iron source ("FeO"), wherein x varies between 0.046 and 0.195, the method comprising: Iron metal is subjected to oxidation reactions at controlled temperatures (T) and oxygen partial pressures (pO2) to obtain iron oxides, including Fe2O3 or Fe3O4; and The iron oxide is subjected to a reduction reaction under a controlled buffer atmosphere to obtain the reactant iron source. The reactant iron source described herein has a defined and reproducible chemical composition and rapid kinetics.

4. The method according to claim 3, wherein the ferrous metal is soft iron, steel, cast iron, or exo-carbonyl iron (carbonyl iron powder).

5. The method according to any one of claims 1 to 4, wherein the reactant iron source is obtained at a temperature above about 560°C, or between 600°C and 850°C, or between 600°C and 1250°C.

6. The method according to any one of claims 1 to 5, wherein the oxygen partial pressure pO2 is 1.4 × 10⁻⁶. -25 and 7.0×10 -17 Between atm or 1.4 × 10 -25 and 3.2×10 -9 Between ATM.

7. The method according to any one of claims 1 to 6, wherein the desired oxygen partial pressure pO2 is achieved by selecting a buffer gas mixture, said buffer gas mixture comprising CO / CO2, H2 / H2O, H2 / O2, CH4 / O2, CH4 / CO2, H2 / CO2, organic compounds suitable for forming a buffer composition by pyrolysis, gasification, or combustion. Preferably, the buffer gas is pure and / or diluted with an inert gas including argon or nitrogen.

8. The method of claim 2, wherein the first iron source comprises particulate material having a particle size between 25 μm and 1 mm in at least one dimension.

9. A reactant iron source ("FeO") obtained by the method according to any one of claims 1 to 8.

10. The general formula is FeO 1+x The reactant iron source ("FeO"), wherein x varies between 0.046 and 0.195, has a defined and reproducible chemical composition and rapid kinetics, wherein the reactant iron source is obtained from a first iron source at a controlled temperature (T) and oxygen partial pressure (pO2).

11. The general formula is FeO 1+x The reactant iron source ("FeO"), wherein x varies between 0.046 and 0.195, has a defined and reproducible chemical composition and rapid kinetics, wherein the reactant iron source is obtained from iron metal via a two-step process comprising oxidizing the iron metal to obtain an iron oxide comprising Fe2O3 or Fe3O4, and then reducing the iron oxide under a controlled buffer atmosphere to produce the reactant iron source.

12. The reactant iron source according to claim 10, wherein the first iron source is iron metal, purified iron oxide, or iron ore. Preferably, the ferrous metal is soft iron, steel, cast iron, or exo-carbonyl iron (carbonyl iron powder).

13. The reactant iron source according to claim 11, wherein the iron metal is soft iron, steel, cast iron or exo-carbonyl iron (carbonyl iron powder).

14. A method for preparing LiFe 1-y M y A method for a cathode material of PO4 or a cathode material having a composition of lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP), wherein M is a substituted metal of iron and y varies between 0 and 0.9, the method comprising reacting a reactant iron source according to any one of claims 1 to 13 with a lithium source and a phosphate source and optionally a manganese source or a substituted metal M.

15. The method of claim 14, wherein the reactant iron source is used as a single iron source.

16. The method according to claim 14 or 15, wherein it is a melting method, a semi-melting method, or a solid method.

17. The method according to claim 14 or 15, wherein it is a melting method.

18. The method of claim 17, wherein the reaction time is less than about 30 minutes, or less than about 10 minutes, or about 2 minutes.

19. The method of claim 17, wherein the reaction temperature is between 660°C and 1300°C or between 900°C and 1200°C, and wherein the reaction is carried out under an oxygen buffer atmosphere. Optionally, the reaction is followed by a cooling and solidification step to obtain a reactant iron source in the form of ingots or atomized droplets.

20. The method according to any one of claims 14 to 19, wherein the lithium source is Li2CO3, LiOH, Li2SO4, LiH2PO4, LiPO3, Li3PO4 or a mixture thereof, such as a LiPO3-Li3PO4 mixture; and the phosphate source is P2O5, H3PO4, HPO3, ammonium monohydrogen phosphate (MAP) or dihydrogen phosphate (DAP), or related chemicals including LiH2PO4, LiPO3, Li3PO4 and mixtures thereof, such as a LiPO3-Li3PO4 mixture.

21. The method according to any one of claims 14 to 20, wherein the cathode material is obtained in the form of ingots or pulverized ingots. Optionally, the ingot or pulverized ingot may be further subjected to at least one other process, including micronization, to obtain a homogeneous granulated powder. Optionally, the homogeneous granulated powder may be further subjected to submicronization by dry milling, wet milling, or jet milling to obtain submicronized powder. Optionally, the submicronized powder may be further subjected to pyrolysis in the presence of at least one carbon source to obtain an electrochemically active cathode material.

22. The method according to any one of claims 14 to 21, wherein the cathode material has an olivine structure.

23. The reactant iron source ("FeO") according to any one of claims 9 to 13, used to prepare LiFe 1- y M y In methods for preparing cathode materials of PO4, where M is iron or a metal substituted with iron and y varies between 0 and 0.9, or in methods for preparing lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP) compositions.

24. The reactant iron source ("FeO") according to any one of claims 9 to 13 in the preparation of LiFe 1-y M y Use in methods of producing PO4 and cathode materials in which M is iron or a metal substituted for iron and y varies between 0 and 0.9, or in methods of preparing lithium iron phosphate (LFP) or lithium manganese iron phosphate (LMFP) compositions.

25. The cathode material obtained by the method according to any one of claims 14 to 22.

26. A battery having a cathode comprising a material obtained by the method according to any one of claims 14 to 22.

27. A battery manufacturing plant that implements the method according to any one of claims 1 to 8 and 14 to 22.

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