Ferromanganese phosphate material as well as preparation method and application thereof
By controlling the preparation of manganese iron phosphate materials through spray pyrolysis, the problem of uniform distribution of Mn and Fe elements in lithium manganese iron phosphate materials was solved, the rate performance of the materials was improved, the process flow was simplified, and wastewater generation was reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WANHUA CHEM GRP BATTERY TECH CO LTD
- Filing Date
- 2024-10-31
- Publication Date
- 2026-05-08
AI Technical Summary
The rate performance of lithium manganese iron phosphate materials in the current technology needs to be further improved, and the co-precipitation method makes it difficult for Mn and Fe elements to be evenly distributed, which affects the battery performance.
Manganese iron phosphate material was prepared by spray pyrolysis. By controlling the pH value of the mixture and materials and carrying out spray pyrolysis at specific temperature, pressure and flow rate, the uniform precipitation of Mn and Fe elements was ensured, the element loss during solid-liquid separation was avoided and the process was simplified.
Precise control of Mn and Fe elements in lithium manganese iron phosphate materials has been achieved, improving the rate performance of lithium manganese iron phosphate materials, simplifying the preparation process, and reducing wastewater generation.
Smart Images
Figure CN121990544A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of secondary battery technology, specifically relating to a manganese iron phosphate material, its preparation method, and its application. Background Technology
[0002] Lithium iron phosphate (LFP) has been widely used in electric vehicles due to its advantages such as good safety, long cycle life, and low cost. However, the energy density of LFP materials themselves limits their application in long-range vehicles. Introducing manganese ions into LFP can increase the operating voltage from 3.4V to 4.1V and improve the energy density by 15%-20%. It also possesses advantages such as long cycle life, high thermal stability, and strong safety, making it a promising candidate for use in long-range vehicles.
[0003] In existing technologies, lithium manganese iron phosphate materials are usually prepared by co-precipitation, but the rate performance of the resulting materials still needs to be further improved. Summary of the Invention
[0004] This application provides a manganese iron phosphate material, its preparation method, and its application, in order to address the issue that the rate performance of lithium manganese iron phosphate materials needs further improvement.
[0005] In a first aspect, this application provides a method for preparing ferromanganese phosphate material, comprising the following steps:
[0006] S1, mix iron salt solution, manganese salt solution, phosphoric acid solution and pH adjuster solution to obtain mixture A, and control the pH of mixture A to be 0.8-1.6;
[0007] S2, the mixture A is mixed with ammonia water to obtain mixture B, and the pH of mixture B is controlled to be 6-7;
[0008] S3, the obtained mixture B is subjected to spray pyrolysis. The spray pyrolysis treatment temperature is 500℃-750℃, the atomization pressure is 0.3MPa-0.8MPa, and the feed flow rate is 2L / min-60L / min to obtain manganese iron phosphate material.
[0009] In some embodiments, in step S1, the anions in the iron salt solution, manganese salt solution, and pH adjuster are of the same type, optionally chloride ions or nitrate ions.
[0010] In some embodiments, the spray pyrolysis treatment is carried out at a temperature of 550°C-650°C, an atomization pressure of 0.4MPa-0.6MPa, and a feed flow rate of 20L / min-30L / min.
[0011] In some embodiments, in step S1, the molar ratio of (Fe+Mn):P in the mixture A is 1:(1-1.05) based on elemental composition; the molar ratio of Mn:Fe is x:(1-x), where 0.2≤x≤0.8.
[0012] In some embodiments, in step S1, the total concentration of iron salt and manganese salt in the mixture A is between 1 mol / L and 4 mol / L.
[0013] Secondly, this application provides a manganese iron phosphate material, which is prepared by the above-described preparation method.
[0014] Thirdly, this application provides a lithium manganese iron phosphate material, which is prepared using the aforementioned iron manganese phosphate material.
[0015] Fourthly, this application provides a method for preparing lithium manganese iron phosphate material, comprising the following steps:
[0016] S11, the above-mentioned manganese iron phosphate material, lithium source, carbon source, additives and water are mixed to obtain slurry A;
[0017] S12, spray dry slurry A to obtain powder B;
[0018] S13, powder B is sintered and pulverized under a non-reactive atmosphere to obtain lithium manganese iron phosphate material.
[0019] In some embodiments, the preparation method of the lithium manganese iron phosphate material satisfies at least one of the following (1)-(10):
[0020] (1) In step S11, the molar ratio of Li:(Fe+Mn) is (1-1.05):1, based on elements.
[0021] (2) The mass ratio of the carbon source to the manganese iron phosphate material is 0.05-0.2:1;
[0022] (3) The mass ratio of the additive to the manganese ferric phosphate material is 0.002-0.01:1;
[0023] (4) The solid content of the slurry A is 20-50 wt%;
[0024] (5) The lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxide;
[0025] (6) The carbon source includes at least one of glucose, sucrose, polyethylene glycol, and starch;
[0026] (7) The additives include at least one of titanium dioxide, magnesium oxide, zirconium oxide, yttrium oxide, and vanadium pentoxide;
[0027] (8) The inlet air temperature of the spray dryer is 220-260℃, and the outlet air temperature is 105-120℃;
[0028] (9) The sintering temperature is 600-850℃ and the sintering time is 4-20h;
[0029] (10) In step S13, the material is crushed until the particle size Dv50 is 0.6-1.5μm.
[0030] Fifthly, this application provides a positive electrode sheet, comprising:
[0031] Positive current collector, and
[0032] A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer comprising the above-mentioned lithium manganese iron phosphate material or the lithium manganese iron phosphate material prepared by the above-mentioned preparation method.
[0033] Sixthly, this application provides a secondary battery, including the aforementioned positive electrode plate.
[0034] Seventhly, this application provides an electrical device including the aforementioned secondary battery.
[0035] The technical solution of this application has the following advantages:
[0036] The method for preparing ferromanganese phosphate material provided in this application includes the following steps: S1, mixing iron salt solution, manganese salt solution, phosphoric acid solution, and pH adjuster solution to obtain mixture A, controlling the pH of mixture A to be 0.8-1.6; S2, mixing mixture A with ammonia water to obtain mixture B, controlling the pH of mixture B to be 6-7; S3, subjecting the obtained mixture B to spray pyrolysis, wherein the spray pyrolysis treatment temperature is 500℃-750℃, the atomization pressure is 0.3MPa-0.8MPa, and the feed flow rate is 2L / min-60L / min, to obtain ferromanganese phosphate material. The preparation method provided in this application, by limiting the pH at both the mixture A and the mixture B, enables the uniform precipitation of Mn and Fe elements in the raw materials, resulting in a uniform element distribution in the obtained ferromanganese phosphate material. By directly subjecting the mixture B to spray pyrolysis, this application avoids element loss during solid-liquid separation, ensuring that all Mn and Fe elements in the raw materials are incorporated into the final product, achieving precise control of Mn and Fe elements in the ferromanganese phosphate material. Simultaneously, the precise control of Mn and Fe elements in the ferromanganese phosphate material is achieved through spray pyrolysis technology under specific conditions, ensuring complete reaction, good crystallinity, and preventing the generation of impurities such as ferropyrophosphate from side reactions. Compared with conventional methods, this method eliminates the need for high-temperature aging, crystal transformation, solid-liquid separation, washing, and sintering steps, resulting in a simpler process, shorter reaction time, and no large amount of wastewater generated.
[0037] The method for preparing ferromanganese phosphate provided in this application uses the same anion in the iron salt solution, manganese salt solution, and pH adjuster, which is either chloride or nitrate ions. By limiting the anion, this application enables the anions in the raw materials to be removed in gaseous form during subsequent spray pyrolysis, eliminating the need for a water washing step, avoiding the generation of waste liquid, and facilitating solvent recovery during subsequent spray pyrolysis by using the same anion, thus reducing the introduction of impurities.
[0038] The method for preparing ferromanganese phosphate provided in this application obtains precisely proportioned ferromanganese phosphate by controlling the elemental ratio of Mn, Fe, and P in the raw materials.
[0039] The lithium manganese iron phosphate material provided in this application is prepared using the ferromanganese phosphate material provided in this application. Because the Mn and Fe elements in the ferromanganese phosphate material are evenly distributed, the rate performance of the lithium manganese iron phosphate material is improved. Attached Figure Description
[0040] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0041] Figure 1 This is the XRD pattern of the lithium manganese iron phosphate material provided in Example 1 of this application. Detailed Implementation
[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0043] 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 application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0045] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0046] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0047] In the description of the embodiments of this application, the term "at least one" refers to two or more (including two).
[0048] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0049] As mentioned earlier, the existing technology typically uses co-precipitation to prepare lithium manganese iron phosphate materials. However, due to the significant difference in the solubility products (Ksp) of Mn and Fe phosphates, Fe and Mn are difficult to distribute uniformly in the main structure of the material during the co-precipitation preparation of the precursor, which can lead to Mn... 3+ The Jahn-Teller effect is severe, affecting the rate performance of the battery. Furthermore, existing co-precipitation methods generally include a solid-liquid separation step, which leads to elemental loss.
[0050] To address the problems existing in the aforementioned related technologies, according to the first aspect of this application, a method for preparing ferromanganese phosphate material includes the following steps:
[0051] S1, mix iron salt solution, manganese salt solution, phosphoric acid solution and pH adjuster solution to obtain mixture A, and control the pH of mixture A to be 0.8-1.6;
[0052] S2, the mixture A is mixed with ammonia water to obtain mixture B, and the pH of mixture B is controlled to be 6-7;
[0053] S3, the obtained mixture B is subjected to spray pyrolysis. The spray pyrolysis treatment temperature is 500℃-750℃, the atomization pressure is 0.3MPa-0.8MPa, and the feed flow rate is 2L / min-60L / min to obtain manganese iron phosphate material.
[0054] The preparation method provided in this application, by limiting the pH at both the mixture A and the mixture B, enables the uniform precipitation of Mn and Fe elements in the raw materials, resulting in a uniform element distribution in the obtained ferromanganese phosphate material. If the pH of the mixture A is too high, ferric phosphate / manganese phosphate precipitation will occur, leading to uneven precipitation. If the pH of the mixture B is too low, element precipitation will be incomplete, resulting in a deviation in the manganese-iron ratio in the obtained ferromanganese phosphate. Both a low pH in the mixture A and a high pH in the mixture B will lead to an increase in the amount of ammonia used in step S2, potentially generating precipitates such as ammonium ferric phosphate. This application directly sprays and pyrolyzes the mixture B, avoiding elemental losses during solid-liquid separation. This ensures that all Mn and Fe elements in the raw materials are incorporated into the final product, achieving precise control of Mn and Fe elements in the ferromanganese phosphate material. This guarantees complete reaction, good crystallinity, and prevents side reactions that produce impurities such as ferropyrophosphate. In this application, if the spray pyrolysis temperature is too low, the reactants cannot be fully pyrolyzed, resulting in poor product crystallinity. Conversely, if the temperature is too high, phosphates may polymerize, producing impurities such as ferropyrophosphate. If the atomization pressure is too low, the product particles spend too long in the high-temperature reactor, causing agglomeration and larger particle size. If the pressure is too high, the product spends too little time in the high-temperature reactor, leading to incomplete pyrolysis and poor product crystallinity. Furthermore, if the feed flow rate during spray pyrolysis is too low, the system's solid content will be low, causing ferromanganese phosphate particles to sinter and agglomerate, resulting in larger particle size. Conversely, if the feed rate is too high, incomplete pyrolysis and poor product crystallinity will result. Meanwhile, compared with conventional methods, it does not require steps such as high-temperature aging, crystal transformation, solid-liquid separation, washing, and sintering. The process is simple, the reaction time is short, and it does not generate a large amount of wastewater.
[0055] In some embodiments, the pH of mixture A can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, or within any range of the above values; the pH of mixture B can be 6, 6.1, 6.3, 6.5, 6.7, 6.8, 6.9, 7, or within any range of the above values. For example, the spray pyrolysis temperature can be 500℃, 530℃, 550℃, 580℃, 600℃, 620℃, 650℃, 670℃, 710℃, 750℃, etc., or within any range of the above values; the atomization pressure can be 0.3Mpa, 0.35Mpa, 0.4Mpa, 0.5Mpa, 0.6Mpa, 0.77Mpa, 0.8Mpa, etc., or within any range of the above values; the feed flow rate can be 2L / min, 8L / min, 15L / min, 20L / min, 23L / min, 25L / min, 28L / min, 30L / min, 40L / min, 45L / min, 50L / min, 55L / min, 60L / min, etc., or within any range of the above values.
[0056] In some embodiments, the iron salt solution is a trivalent iron salt solution, which can be a solution obtained by dissolving a directly soluble salt, or a solution obtained by dissolving iron powder or iron oxide in a corresponding acid and then oxidizing it.
[0057] In some embodiments, the manganese salt solution is a solution obtained by dissolving a directly soluble salt, or a solution obtained by dissolving manganese oxide in a corresponding acid.
[0058] In some embodiments, in step S1, the anions in the iron salt solution, manganese salt solution, and pH adjuster are of the same type, optionally chloride ions or nitrate ions.
[0059] This application, by limiting the presence of anions, enables the removal of anions in the raw material in gaseous form during subsequent spray pyrolysis, eliminating the need for water washing and preventing waste liquid generation. The presence of anions also facilitates solvent recovery during later spray pyrolysis, reducing the introduction of impurities.
[0060] In some embodiments, the spray pyrolysis treatment is carried out at a temperature of 550°C-650°C, an atomization pressure of 0.4MPa-0.6MPa, and a feed flow rate of 20L / min-30L / min.
[0061] This application ensures complete reaction and good crystallinity by optimizing the spray pyrolysis treatment parameters; at the same time, it avoids side reactions that produce impurities such as ferric pyrophosphate.
[0062] In some embodiments, in step S1, the molar ratio of (Fe+Mn):P in the mixture A, based on elemental composition, is 1:(1-1.05). For example, the molar ratio of (Fe+Mn):P can be 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, etc., or fall within any range of the above values.
[0063] This application achieves a precise ratio of Mn, Fe, and P in the final manganese ferric phosphate by limiting the molar ratio of elements in the raw materials, which can ensure that all Mn and Fe in the raw materials are incorporated into the final product and avoid element loss.
[0064] In some embodiments, in step S1, the total concentration of iron salt and manganese salt in the mixture A is between 1 mol / L and 4 mol / L.
[0065] This application achieves the effect of uniform precipitation of Mn and Fe elements by controlling the total concentration of iron and manganese salts in the mixed solution A; too high a concentration will cause segregation of Mn or Fe elements, while too low a concentration will result in low production efficiency and excessively large manganese ferric phosphate particles.
[0066] Secondly, this application provides a manganese iron phosphate material prepared by the above-described preparation method. Because the Mn and Fe elements in the manganese iron phosphate material are uniformly distributed, the rate performance of the lithium manganese iron phosphate material is improved.
[0067] Thirdly, this application provides a lithium manganese iron phosphate material, which is prepared using the aforementioned iron manganese phosphate material.
[0068] Fourthly, this application provides a method for preparing lithium manganese iron phosphate material, comprising the following steps:
[0069] S11, the manganese iron phosphate material as described in claim 8, lithium source, carbon source, additives, and water are mixed to obtain slurry A;
[0070] S12, spray dry slurry A to obtain powder B;
[0071] S13, powder B is sintered and pulverized under a non-reactive atmosphere to obtain lithium manganese iron phosphate material.
[0072] In some embodiments, the preparation method of the lithium manganese iron phosphate material satisfies at least one of the following (1)-(10):
[0073] (1) In step S11, the molar ratio of Li:(Fe+Mn) is (1-1.05):1 in terms of elements; as an example, the molar ratio of Li:(Fe+Mn) is 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, or within any of the above values.
[0074] (2) The mass ratio of the carbon source to the manganese iron phosphate material is 0.02-0.1:1; as an example, the mass ratio of the carbon source to the manganese iron phosphate material is 0.02:1, 0.04:1, 0.05:1, 0.06:1, 0.08:1, 0.1:1, or within any of the above values.
[0075] (3) The mass ratio of the additive to the ferromanganese phosphate material is 0.005-0.02:1; as an example, the mass ratio of the additive to the ferromanganese phosphate material is 0.005:1, 0.008:1, 0.01:1, 0.012:1, 0.015:1, 0.017:1, 0.02:1, or within any of the above values.
[0076] (4) The solid content of the slurry A is 20-50 wt%; as an example, the solid content of the slurry is 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, or within any of the above values.
[0077] (5) The lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxide;
[0078] (6) The carbon source includes at least one of glucose, sucrose, polyethylene glycol, and starch;
[0079] (7) The additives include at least one of titanium dioxide, magnesium oxide, zirconium oxide, yttrium oxide and vanadium pentoxide.
[0080] (8) The inlet air temperature of the spray dryer is 220-260℃ and the outlet air temperature is 105-120℃; as an example, the inlet air temperature is 220℃, 230℃, 240℃, 250℃, 260℃, or within any of the above values; the outlet air temperature is 105℃, 108℃, 110℃, 113℃, 115℃, 118℃, 120℃, or within any of the above values.
[0081] (9) The sintering temperature is 600-850℃ and the sintering time is 4-20h; as an example, the sintering temperature is 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, or within any range of the above values; the sintering time is 4h, 8h, 10h, 12h, 16h, 18h, 20h, 24h, or within any range of the above values.
[0082] (10) In step S13, the material is pulverized to a particle size Dv50 of 0.6-1.5 μm; as an example, the particle size Dv50 is 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.3 μm, 1.5 μm, or within any of the above values.
[0083] Fifthly, this application provides a positive electrode sheet, comprising:
[0084] Positive current collector, and
[0085] A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer comprising the above-mentioned lithium manganese iron phosphate material or the lithium manganese iron phosphate material prepared by the above-mentioned preparation method.
[0086] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.
[0087] In some embodiments, the positive electrode active material layer in the positive electrode sheet of this application does not exclude other positive electrode active materials besides the lithium manganese iron phosphate material described in the third aspect of this application. For example, other positive electrode active materials may be positive electrode active materials known in the art for use in batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), iron pyrophosphate (Li2FeP2O7), lithium cobalt oxide (LiCoO2), spinel-type lithium manganese oxide (LiMn2O4), and spinel-type lithium nickel manganese oxide (LiNi). 0.5 Mn 1.5 Lithium manganese oxide (LiMnO2), lithium nickel oxide (LiNiO2), lithium niobate (LiNbO2), lithium ferrite (LiFeO2), lithium magnesium oxide (LiMgO2), lithium calcium oxide (LiCaO2), lithium copper oxide (LiCuO2), lithium zinc oxide (LiZnO2), lithium molybdate (LiMoO2), lithium tantalate (LiTaO2), lithium tungstate (LiWO2), lithium nickel cobalt aluminum oxide (LiNiO2). x Co y Al 1-x-yO2, where 0 < x < 1, 0 < y < 1, 0 < x + y < 1, such as LiNi 0.8 Co 0.15 Al 0.05 O2), lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2, where 0 < x < 1, 0 < y < 1, 0 < x + y < 1, such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, etc.), lithium-rich materials (such as lithium-rich nickel cobalt manganese oxide), manganese oxide (MnO2), vanadium oxide, sulfur oxide, silicate oxide, and at least one of their respective modified compounds.
[0088] The modified compounds of the above positive electrode active materials can be doping modification, surface coating modification, or simultaneous doping and coating modification of the positive electrode active materials, etc.
[0089] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
[0090] In some embodiments, the positive electrode active material layer can further include a binder. As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.
[0091] In some embodiments, the positive electrode active material layer can further include a conductive agent. As an example, the conductive agent can include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0092] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.
[0093] Sixthly, this application provides a secondary battery, including the aforementioned positive electrode plate.
[0094] Typically, a secondary battery also includes a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.
[0095] [Negative electrode plate]
[0096] The negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, wherein the negative active material layer includes a negative active material.
[0097] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.
[0098] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
[0099] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
[0100] In some embodiments, the negative electrode active material layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).
[0101] In some embodiments, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0102] In some embodiments, the negative electrode active material layer may also include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).
[0103] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.
[0104] [Electrolytes]
[0105] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.
[0106] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.
[0107] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.
[0108] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.
[0109] In some embodiments, the electrolyte may also include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
[0110] [Isolation membrane]
[0111] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.
[0112] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.
[0113] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.
[0114] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.
[0115] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.
[0116] This application does not impose any particular restrictions on the shape of the secondary battery; it can be cylindrical, square, or any other arbitrary shape.
[0117] In some implementations, the secondary batteries can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.
[0118] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.
[0119] Seventhly, this application provides an electrical device including the aforementioned secondary battery.
[0120] In some embodiments, the aforementioned electrical device may also include a battery module or battery pack assembled from the aforementioned secondary batteries. The secondary batteries, battery modules, or battery packs can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
[0121] As the electrical device, a secondary battery, battery module, or battery pack can be selected according to its usage requirements. An example electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the secondary battery for this electrical device, a battery pack or battery module can be used.
[0122] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use rechargeable batteries as their power source.
[0123] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.
[0124] Example 1
[0125] This embodiment provides a lithium manganese iron phosphate material, the specific preparation steps and operating parameters of which are as follows:
[0126] (1) Prepare a 5 mol / L iron salt (ferric chloride) solution, a 5 mol / L manganese salt (manganese chloride) solution, an 85 wt% phosphoric acid solution, and a 10 wt% pH adjuster (HCl) solution.
[0127] (2) The above solution is prepared into a mixture A in a certain proportion, wherein, in terms of elements, the molar ratio of Mn:Fe:P is 6:4:10, the pH of the mixture A is 1.2, and the total concentration of iron salt and manganese salt in the mixture A is 2 mol / L;
[0128] (3) Mix the mixture A with ammonia water to obtain mixture B, and control the pH of mixture B to be 6.3;
[0129] (4) The mixture is subjected to spray pyrolysis at a temperature of 600℃, an atomization pressure of 0.5MPa, and a feed flow rate of 30L / min to obtain manganese iron phosphate powder; at the same time, the evaporated solvent is recovered and tested for metal content during the spray pyrolysis process.
[0130] (5) Manganese ferric phosphate powder, lithium carbonate, glucose, titanium dioxide and pure water are mixed and dispersed by sand milling to obtain slurry A; wherein, based on elements, the molar ratio of Li:(Fe+Mn) is 1.02:1, the mass ratio of the carbon source to manganese ferric phosphate is 0.1:1, the mass ratio of the additive to manganese ferric phosphate is 0.005:1, and the solid content of the slurry is 40wt%.
[0131] (6) Spray drying of slurry A to obtain powder B; wherein the spray drying temperature is: inlet air temperature 230℃, outlet air temperature 120℃;
[0132] (7) Powder B was sintered in an inert atmosphere at a temperature of 750°C for 8 hours. The powder was then crushed and sieved to obtain lithium manganese iron phosphate with a particle size of 1 μm (Dv50).
[0133] Figure 1 The XRD pattern of the obtained lithium manganese iron phosphate material is shown in the figure. As can be seen from the figure, it is a pure lithium manganese iron phosphate phase without other impurities. The other embodiments also provide pure lithium manganese iron phosphate, and their XRD patterns are not shown one by one.
[0134] Example 2
[0135] This embodiment provides a lithium manganese iron phosphate material. Compared with embodiment 1, the only difference is that ferric nitrate is used instead of ferric chloride in step (1), and the pH of mixture B in step (3) is 7.0.
[0136] Example 3
[0137] This embodiment provides a lithium manganese iron phosphate material. Compared with embodiment 1, the only difference is that in the mixture A in step (2), the molar ratio of Mn:Fe:P is 7:3:10 in terms of elements, and the pH of the mixture B in step (3) is 7.
[0138] Example 4
[0139] This embodiment provides a lithium manganese iron phosphate material. Compared with Example 1, the only difference is that in the mixture A in step (2), the molar ratio of Mn:Fe:P is 6:4:10.2 in terms of elements, and the pH of the mixture B in step (3) is 7.
[0140] Example 5
[0141] This embodiment provides a lithium manganese iron phosphate material, the specific preparation steps and operating parameters of which are as follows:
[0142] (1) Prepare a 4 mol / L iron salt (ferric chloride) solution, a 4 mol / L manganese salt (manganese chloride) solution, an 85 wt% phosphoric acid solution, and a 10 wt% pH adjuster (HCl) solution.
[0143] (2) The above solution is prepared into a mixture A in a certain proportion, wherein the molar ratio of Mn:Fe:P is 6:4:10 based on elements, the pH of the mixture A is 0.8, and the total concentration of iron salt and manganese salt in the mixture A is 1.5 mol / L;
[0144] (3) Mix the mixture A with ammonia water to obtain mixture B, and control the pH of mixture B to be 6;
[0145] (4) The mixture is subjected to spray pyrolysis at a temperature of 525℃, an atomization pressure of 0.3MPa, and a feed flow rate of 5L / min to obtain manganese iron phosphate powder; at the same time, the evaporated solvent is recovered and tested for metal content during the spray pyrolysis process.
[0146] (5) Manganese iron phosphate powder, lithium carbonate (lithium source), glucose (carbon source), titanium dioxide (additive), and pure water are mixed and dispersed by sand milling to obtain slurry A; wherein, based on elements, the molar ratio of Li:(Fe+Mn) is 1.01:1, the mass ratio of the carbon source to manganese iron phosphate is 0.06:1, the mass ratio of the additive to manganese iron phosphate is 0.015:1, and the solid content is 48wt%.
[0147] (6) Spray drying of slurry A to obtain powder B; wherein the spray drying temperature is: inlet air temperature 220℃, outlet air temperature 110℃;
[0148] (7) Powder B was sintered in an inert atmosphere at a temperature of 625°C for 12 hours. The powder was then crushed and sieved to obtain lithium manganese iron phosphate with a Dv50 particle size of 1.3 μm.
[0149] Example 6
[0150] This embodiment provides a lithium manganese iron phosphate material, the specific preparation steps and operating parameters of which are as follows:
[0151] (1) Prepare a 4 mol / L iron salt (ferric nitrate) solution, a 5 mol / L manganese salt (manganese nitrate) solution, an 85 wt% phosphoric acid solution, and a 10 wt% pH adjuster (HCl) solution.
[0152] (2) The above solution is prepared into a mixture A in a certain proportion, wherein, in terms of elements, the molar ratio of Mn:Fe:P is 6:4:10, the pH of the mixture A is 1.5, and the total concentration of iron salt and manganese salt in the mixture A is 3.5 mol / L;
[0153] (3) Mix the mixture A with ammonia water to obtain mixture B, and control the pH of mixture B to be 7;
[0154] (4) The mixture is subjected to spray pyrolysis at a temperature of 680℃, an atomization pressure of 0.7MPa, and a feed flow rate of 50L / min to obtain manganese iron phosphate powder; at the same time, the evaporated solvent is recovered and tested for metal content during the spray pyrolysis process.
[0155] (5) Manganese iron phosphate powder, lithium carbonate (lithium source), glucose (carbon source), titanium dioxide (additive), and pure water are mixed and dispersed by sand milling to obtain slurry A; wherein, based on elements, the molar ratio of Li:(Fe+Mn) is 1.04:1, the mass ratio of the carbon source to manganese iron phosphate is 0.14:1, the mass ratio of the additive to manganese iron phosphate is 0.007:1, and the solid content is 30wt%.
[0156] (6) Spray drying of slurry A to obtain powder B; wherein the spray drying temperature is: inlet air temperature 230℃, outlet air temperature 120℃;
[0157] (7) Powder B was sintered in an inert atmosphere at a temperature of 810°C for 6 hours. The powder was then crushed and sieved to obtain lithium manganese iron phosphate with a Dv50 particle size of 1.3 μm.
[0158] Example 7
[0159] This embodiment provides a lithium manganese iron phosphate material. The only difference from embodiment 1 is that in step (5), the lithium source is lithium hydroxide.
[0160] Example 8
[0161] This embodiment provides a lithium manganese iron phosphate material. The only difference from embodiment 1 is that in step (5), the carbon source is polyethylene glycol (PEG2000).
[0162] Example 9
[0163] This embodiment provides a lithium manganese iron phosphate material. The only difference from embodiment 1 is that in step (5), the additive is zirconium oxide.
[0164] Comparative Example 1
[0165] This comparative example provides a lithium manganese iron phosphate material. The only difference from Example 1 is that no pH adjuster was added in step (2), and the pH of the resulting mixture A is 2.8.
[0166] Comparative Example 2
[0167] This comparative example provides a lithium manganese iron phosphate material, which differs from Example 1 only in that the pH of the mixture B is controlled to be 4.1 in step (3).
[0168] Comparative Example 3
[0169] This comparative example provides a lithium manganese iron phosphate material, which differs from Example 1 only in that the pH of the mixture B is controlled to be 8 in step (3).
[0170] Comparative Example 4
[0171] This comparative example provides a lithium manganese iron phosphate material. The only difference from Example 1 is that the spray pyrolysis temperature in step (4) is 800℃, the atomization pressure is 0.5Mpa, and the feed flow rate is 80L / min.
[0172] Test case
[0173] 1. Preparation and testing method of lithium-ion battery: The lithium manganese iron phosphate positive electrode materials prepared in each example and comparative example were mixed with conductive carbon black and binder PVDF at a weight ratio of 90:5:5 and homogenized. The homogenization parameters were 2000 rpm and 15 min. The solvent was NMP and the solid content of the slurry was 50 wt%. The slurry was coated on carbon-coated aluminum foil with a coating thickness of 200 μm and transferred to a vacuum dryer to dry and obtain the positive electrode material sheet. The drying conditions were 120 °C and 3 h. Then, the positive electrode sheet was cut into round pieces with a diameter of 14 mm and weighed. Using lithium metal sheet as negative electrode, polypropylene microporous membrane as separator, and 1 mol / L LiPF6 / EC+DMC (volume ratio of 1:1) as electrolyte, the assembly was carried out in an argon-filled glove box according to the assembly process of LIR2025 button battery.
[0174] Test method: Test its 0.1C discharge, 1C discharge, and rate performance. The specific test steps are as follows:
[0175] During electrochemical testing, the capacitor was charged at 25°C with a constant current rate of 0.1C to 4.3V, and then discharged at a constant current rate of 0.1C to 2.0V to obtain the 0.1C discharge capacity. It was then charged again with a constant current rate of 1C to 4.3V, and then discharged at a constant current rate of 0.1C to 2.0V to obtain the 1C discharge capacity.
[0176] 2. The content of metal elements in the manganese iron phosphate materials and the recovered solvent provided in each example and comparative example was determined by ICP (inductively coupled plasma) and atomic absorption spectrometry.
[0177] 3. Specific surface area: Tested by nitrogen adsorption method according to GB / T 19587-2017.
[0178] 4. The material was characterized using a Rigaku X-ray powder diffractometer (XRD) from Japan.
[0179] The specific test results are shown in the table below:
[0180] Table 1
[0181]
[0182] Note: The manganese iron phosphate in Examples 7-9 is the same as that in Example 1, and they are from the same batch.
[0183] As shown in Table 1, the Mn, Fe, and P contents in the ferromanganese phosphate and the Mn and Fe contents in the recovered solvent indicate that all three elements in the raw materials of Examples 1-6 are incorporated into the final product with minimal element loss, achieving precise control. The first three columns in the table show the test results at two different locations in the ferromanganese phosphate materials provided in each example and comparative example. The test results show that the results at different locations in the examples are very similar, indicating uniform element distribution. However, in Comparative Examples 1-3, the test results at two different locations differ significantly, indicating that Fe and Mn ions cannot precipitate simultaneously and are unevenly distributed in the target product. Regarding the 0.1C discharge data, the 0.1C discharge of the examples is generally above 149 mA·h / g, with a 1C / 0.1C rate performance above 88.5%. In contrast, the 0.1C discharge of the comparative examples is generally around 145 mA·h / g, with a 1C / 0.1C rate performance below 87%. The manganese iron phosphate obtained in Comparative Example 4 was due to its larger particle size and smaller BET, resulting in lower 0.1C discharge and lower rate.
[0184] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A method for preparing a manganese iron phosphate material, characterized in that, Includes the following steps: S1, mix iron salt solution, manganese salt solution, phosphoric acid solution and pH adjuster solution to obtain mixture A, and control the pH of mixture A to be 0.8-1.6; S2, the mixture A is mixed with ammonia water to obtain mixture B, and the pH of mixture B is controlled to be 6-7; S3, the obtained mixture B is subjected to spray pyrolysis at a temperature of 500℃-750℃, an atomization pressure of 0.3MPa-0.8MPa, and a feed flow rate of 2L / min-60L / min to obtain ferromanganese phosphate material, and the evaporated solvent is recovered.
2. The method for preparing manganese iron phosphate material according to claim 1, characterized in that, In step S1, the anions in the iron salt solution, manganese salt solution, and pH adjuster are all of the same type; Optionally, the anion is a chloride ion or a nitrate ion.
3. The method for preparing manganese iron phosphate material according to claim 2, characterized in that, In step S3, the temperature of the spray pyrolysis treatment is 550℃-650℃, the atomization pressure is 0.4MPa-0.6MPa, and the feed flow rate is 20L / min-30L / min.
4. The method for preparing ferromanganese phosphate material according to any one of claims 1-3, characterized in that, In step S1, in the mixture A, the molar ratio of (Fe+Mn):P is 1:(1-1.05) based on elements; the molar ratio of Mn:Fe is x:(1-x), where 0.2≤x≤0.
8.
5. The method for preparing manganese iron phosphate material according to claim 4, characterized in that, In step S1, the total concentration of iron salt and manganese salt in the mixture A is 1 mol / L-4 mol / L.
6. A manganese iron phosphate material, characterized in that, Prepared by the preparation method according to any one of claims 1-5, optionally, the specific surface area is 5-14 cm². 2 / g.
7. A lithium manganese iron phosphate material, characterized in that, It was prepared using the manganese iron phosphate material described in claim 6.
8. A method for preparing lithium manganese iron phosphate material, characterized in that, Includes the following steps: S11, the manganese iron phosphate material as described in claim 7, lithium source, carbon source, additives, and water are mixed to obtain slurry A; S12, spray dry slurry A to obtain powder B; S13, powder B is sintered and pulverized under a non-reactive atmosphere to obtain lithium manganese iron phosphate material.
9. The method for preparing lithium manganese iron phosphate material according to claim 8, characterized in that, Satisfy at least one of the following (1)-(10): (1) In step S11, the molar ratio of Li:(Fe+Mn) is (1-1.05):1, based on elements. (2) The mass ratio of the carbon source to the manganese iron phosphate material is 0.05-0.2:1; (3) The mass ratio of the additive to the manganese ferric phosphate material is 0.002-0.01:1; (4) The solid content of the slurry A is 20-50 wt%; (5) The lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxide; (6) The carbon source includes at least one of glucose, sucrose, polyethylene glycol, and starch; (7) The additives include at least one of titanium dioxide, magnesium oxide, zirconium oxide, yttrium oxide, and vanadium pentoxide; (8) The inlet air temperature of the spray dryer is 220-260℃, and the outlet air temperature is 105-120℃; (9) The sintering temperature is 600-850℃ and the sintering time is 4-20h; (10) In step S13, the material is crushed until the particle size Dv50 is 0.6-1.5μm.
10. A positive electrode plate, characterized in that, include: Positive current collector, and A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer comprising the lithium manganese iron phosphate material according to claim 7 or the lithium manganese iron phosphate material prepared by the preparation method according to any one of claims 8-9.
11. A secondary battery, characterized in that, Includes the positive electrode sheet as described in claim 12.
12. An electrical appliance, characterized in that, Includes the secondary battery as described in claim 13.