WO2025102463A1 - 前驱体及其制备方法、正极材料、正极极片及锂离子电池 - Google Patents

前驱体及其制备方法、正极材料、正极极片及锂离子电池 Download PDF

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WO2025102463A1
WO2025102463A1 PCT/CN2023/137863 CN2023137863W WO2025102463A1 WO 2025102463 A1 WO2025102463 A1 WO 2025102463A1 CN 2023137863 W CN2023137863 W CN 2023137863W WO 2025102463 A1 WO2025102463 A1 WO 2025102463A1
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precursor
source
lithium
positive electrode
manganese
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English (en)
French (fr)
Inventor
温圣耀
吴婷婷
高建行
刘范芬
苑丁丁
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Eve Power Co Ltd
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Eve Power Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/45—Phosphates containing plural metal, or metal and ammonium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of electrode materials, and in particular to a precursor and a preparation method thereof, a positive electrode material, a positive electrode sheet and a lithium-ion battery.
  • Lithium manganese iron phosphate is a new generation of lithium-ion battery positive electrode material. It has a stable structure during the charge and discharge process, and has a high operating voltage, high energy density and good safety.
  • the present application provides a precursor and a preparation method thereof, a positive electrode material, a positive electrode plate and a lithium-ion battery to solve the above-mentioned technical problems.
  • an embodiment of the present application provides a method for preparing a precursor, comprising the following steps:
  • first raw material components comprising an iron source, a manganese source, a phosphorus source, an M source and hydrogen peroxide
  • first precursor the general formula of the first precursor being Mn x Fe y M z PO 4 ⁇ nH 2 O;
  • M is a metal element
  • x is 0.10 to 0.95
  • y is 0.10 to 0.95
  • z is 0.01 to 0.10
  • the sum of x, y and z is 0.95 to 1.06
  • n is any integer from 0 to 10.
  • an embodiment of the present application provides a precursor, wherein the precursor includes any one of a first precursor, a second precursor, and a third precursor:
  • the general formula of the first precursor is Mn x Fe y M z PO 4 ⁇ nH 2 O;
  • the second precursor includes a core of the general formula Mn x Fe y M z PO 4 ;
  • the third precursor includes a core and a carbon coating layer coated on the outer surface of the core, and the material of the core includes a material with a general formula of Li a Mn x Fe y M z PO 4 ;
  • M is a metal element
  • x is 0.10 to 0.95
  • y is 0.10 to 0.95
  • z is 0.01 to 0.10
  • the sum of x, y and z is 0.95 to 1.06
  • a is 0.95 to 1.10
  • n is any integer from 0 to 10.
  • an embodiment of the present application provides a positive electrode material, wherein the positive electrode material is prepared from a precursor, wherein the precursor includes a precursor prepared by the preparation method described above, or the precursor described above.
  • an embodiment of the present application provides a positive electrode plate, comprising a positive electrode current collector and a coating disposed on one side of the positive electrode current collector, wherein the material of the coating comprises the positive electrode material described above.
  • an embodiment of the present application provides a lithium-ion battery, comprising the positive electrode plate as described above.
  • a precursor for preparing a lithium iron manganese phosphate material is provided.
  • the properties of the lithium iron manganese phosphate material can be better controlled, and the technical problems of low specific energy and poor cycle performance of the lithium iron manganese phosphate can be improved.
  • FIG1 is a schematic flow diagram of a method for preparing a precursor provided in one embodiment of the present application.
  • FIG2 is a schematic flow diagram of a method for preparing a precursor provided in another embodiment of the present application.
  • FIG3 is a schematic flow diagram of a method for preparing a precursor provided in another embodiment of the present application.
  • FIG4 is a schematic diagram of the structure of a lithium-ion battery provided in one embodiment of the present application.
  • FIG5 is a schematic diagram of the structure of the core package in FIG4;
  • FIG6 is a schematic diagram of the structure of the positive electrode sheet in FIG5 ;
  • range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range.
  • a numerical range is indicated in this article, it is meant to include any cited numbers (fractions or integers) within the indicated range.
  • multiple refers to two (times) or more than two (times), for example, it can be two (times), three (times), four (times), five (times), six (times), etc.
  • the selection scope of the term “and/or” includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the said any and all combinations include any combination of two related listed items, any more related listed items, or all related listed items.
  • “A and/or B” includes three parallel solutions of A, B and A+B.
  • the technical solution of "A, and/or, B, and/or, C, and/or, D” includes any one of A, B, C, and D (that is, the technical solution connected by "logical or"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four items of A, B, C, and D (that is, the technical solution connected by "logical and").
  • solid content refers to the ratio of the mass of solid matter in the slurry to the total mass of the slurry.
  • the present application provides a precursor and a preparation method thereof, wherein the precursor may be a first precursor.
  • the present invention can be used as a precursor to prepare a lithium manganese iron phosphate positive electrode material .
  • the present invention can be used as a precursor to prepare a lithium manganese iron phosphate positive electrode material .
  • the Mn and Fe elements in the precursor uniformly form a solid solution, effectively avoiding element segregation, and the proportion of each element in the precursor is optimized and within a preferred proportion range.
  • the precursor can better regulate the characteristics of the lithium manganese iron phosphate positive electrode material, and prepare a positive electrode material with a stable structure, smooth ion channels, high specific energy and long cycle.
  • the positive electrode material includes a core and a carbon coating layer coated on the outer surface of the core, and the core has the following general formula: Li a Mn x Fe y M z PO 4. The specific characteristics of the positive electrode material will be described in detail later, and will not be mentioned here for the time being.
  • the present embodiment provides a method for preparing a first precursor, the method comprising the following steps:
  • the present embodiment provides a method for preparing a second precursor, and the preparation method comprises the following steps:
  • the present embodiment provides a method for preparing a third precursor, and the preparation method comprises the following steps:
  • the first precursor has a general formula of Mn x Fe y M z PO 4 ⁇ nH 2 O.
  • a first precursor can be prepared, and the general formula of the first precursor is MnxFeyMzPO4 ⁇ nH2O .
  • x is 0.10-0.95, for example, it can be 0.10, 0.12, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.91, 0.93, 0.95 and values between any two of the above values
  • y is 0.10-0.95, for example, it can be 0.10, 0.12, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.91, 0.93, 0.95 and values between any two of the above values
  • z is 0.01-0.10, for example, it can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10 and values between any two of the above values.
  • the sum of x, y and z satisfies greater than or equal to 0.95 and less than or equal to 1.06; for example, x+y+z can be 0.95, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, and values between any two of the above values.
  • n is any integer from 0 to 10, for example, it can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.
  • x is 0.40 to 0.70, and when the molar ratio of the Mn element is precisely controlled to meet the above conditions, it is beneficial to balance the specific energy and cycle performance of the lithium manganese iron phosphate positive electrode material to obtain a positive electrode material with both high specific energy and high cycle performance. Furthermore, x is 0.50 to 0.60, within this range, it is helpful to further improve the specific energy and cycle performance.
  • y is 0.30 to 0.60, and when the molar ratio of the Fe element is precisely controlled to meet the above conditions, it is beneficial to balance the specific energy and cycle performance of the lithium manganese iron phosphate positive electrode material to obtain a positive electrode material with both high specific energy and high cycle performance. Furthermore, y is 0.50 to 0.60, within this range, it is helpful to further improve the cycle performance.
  • the ratio of x to y when the ratio of x to y is 0.9 to 1.1, it helps to further improve the cycle performance.
  • z is 0.05 to 0.10, and when the molar ratio of the M element is precisely controlled to meet the above conditions, it is beneficial to balance the specific energy and cycle performance of the lithium manganese iron phosphate positive electrode material to obtain a positive electrode material with both high specific energy and high cycle performance. Furthermore, z is 0.05 to 0.07, within this range, it is helpful to further improve the specific energy and cycle performance.
  • the sum of x, y and z is 0.96 to 0.99.
  • n is 0 or 1 or 2.
  • M represents a doped metal element. By doping the M metal element, it helps to improve the lithium ion diffusion channel in the positive electrode material, thereby improving the conductivity of the positive electrode material. In addition, the doped metal element M can form a more stable lattice skeleton with oxygen, thereby enhancing the stability of the structure, and helping to improve the rate performance, cycle stability and energy density.
  • the M element includes but is not limited to one or more elements of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum; it can be understood that M can be one element, or two, three or more elements.
  • the metal elements contained in M the phosphates of some of the metal elements have an olivine structure.
  • the phosphate of the M element and the manganese phosphate or the iron phosphate are all configured as an olivine structure, thereby constituting a multinary olivine-based positive electrode material.
  • the charge and discharge curve and the cycle performance curve of the multinary olivine-based positive electrode material can be regarded as the linear superposition of the charge and discharge curve and the cycle performance curve of the olivine structure constituted by the phosphate of each metal element, thereby effectively improving the cycle performance of the positive electrode material.
  • the iron source refers to a raw material compound for providing the iron element, and can be any compound containing the iron element that is commonly used in the preparation of positive electrode materials in the art, for example, it can include but is not limited to one or more of iron powder, inorganic iron salts and organic iron salts, wherein the inorganic iron salts include ferrous sulfate, ferric phosphate, phosphorus
  • the organic iron salt comprises one or more of ferrous hydrogen phosphate and ferrous dihydrogen phosphate, and the organic iron salt comprises one or more of ferrous acetate, ferrous oxalate, ferrous tartrate, ferrous lactate and ferrous formate.
  • the manganese source refers to a raw material compound for providing manganese element, and can be any compound containing manganese element that is commonly used in the preparation of positive electrode materials in the art, for example, it can include but is not limited to one or more of inorganic manganese salts and organic manganese salts, the inorganic manganese salts include one or more of manganese sulfate, manganese carbonate, manganese nitrate, manganese phosphate, and manganese hydrogen phosphate, and the organic manganese salts include one or more of manganese acetate and manganese oxalate.
  • the M source refers to a raw material compound for providing the M element, which can be any compound containing the M element commonly used in the preparation of positive electrode materials in the art, for example, it can include but is not limited to one or more of organic M salts and inorganic M salts, the organic M salts include one or more of the formate of the M element, the acetate of the M element, the glycolate of the M element, the lactate of the M element, the tartrate of the M element, and the oxalate of the M element, the inorganic M salt includes at least one of the phosphate of the M element, the hydrogen phosphate of the M element, the dihydrogen phosphate of the M element, the carbonate of the M element, the oxide of the M element, the hydroxide of the M element, the fluoride of the M element, the chloride of the M element, the nitrate of the M element, the sulfate of the M element, and the bromide of the M element, wherein the M element includes one or more of
  • the phosphorus source refers to a raw material compound for providing phosphorus, including but not limited to one or both of phosphoric acid and ammonium dihydrogen phosphate. It can be understood that in some embodiments, when the iron source, manganese source, M source and other compounds used in the multiple first raw material components also contain phosphorus, the compound can also be used as a phosphorus source.
  • the iron source, manganese source, phosphorus source, M source and hydrogen peroxide are fully contacted by mixing to form a mixed phase.
  • the molar ratio of the manganese element in the manganese source, the iron element in the iron source, the M element in the M source and the phosphorus element in the phosphorus source is (0.10-0.95):(0.10-0.95):(0.01-0.10): 1 .
  • the molar ratio of each element in the first precursor can be controlled to obtain MnxFeyMzPO4 ⁇ nH2O .
  • the molar ratio of the hydrogen peroxide to the iron element in the iron source is (2-3):1, for example, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1 and values between any two of the above values.
  • the plurality of first raw material components further include a complexing agent
  • the complexing agent includes one or more of HEDP (hydroxyethyl diphosphonic acid), ATMP (aminotrimethylphosphonic acid) and DTPA (diacetic acid tetramine).
  • the added mass of the complexing agent is 0.1-1wt% of the mass of the iron source, for example, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt% and values between any two of the above values.
  • the second precursor may be a precursor material without a carbon layer.
  • the second precursor is a material with a general formula of MnxFeyMzPO4
  • the carbon content in the second precursor is 0.
  • the second precursor may also be a precursor material with a carbon layer .
  • the second precursor includes a core and a carbon layer attached to the surface of the core, and the core includes a material with a general formula of MnxFeyMzPO4 .
  • the mass of the carbon layer accounts for a percentage of less than or equal to 5% of the mass of the second precursor, for example, a value greater than 0 and less than 0.01%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, and a value between any two of the above values.
  • the carbon layer refers to the carbon attached to the outer surface of the core, which can be a continuous film layer that completely covers the core, or a discontinuous film layer that only covers part of the surface of the core.
  • step S20
  • the calcination temperature can be 550-750°C, for example, 550°C, 560°C, 580°C, 600°C, 620°C, 650°C, 670°C, 690°C, 700°C, 710°C, 730°C, 750°C and values between any two of the above values.
  • the second precursor has a carbon layer.
  • a compound of carbon element needs to be provided.
  • the present application names the compound of the carbon element source of the carbon layer in the second precursor as the first carbon source.
  • the first carbon source includes one or more of an organic metal salt, an organic carbon source and an inorganic carbon source, and the organic metal salt includes one or more of an organic iron salt, an organic manganese salt, and an organic M source, and the organic carbon source includes one or more of glucose, sucrose, lactose, starch, organic acid, vitamin, polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), hydroxyethyl diphosphonic acid, aminotrimethylphosphonic acid, diacetate tetramine and phenolic resin, and the inorganic carbon source includes one or more of graphene, carbon nanotubes and graphite.
  • the organic metal salt is composed of a metal cation and an organic anion, and because the organic anion contains a carbon element, it
  • step S20 can be implemented as follows: providing a calcined material, and calcining the calcined material under the protection of an inert gas to obtain a second precursor, wherein the inert gas includes one or more of nitrogen, argon, and helium.
  • the first carbon source may be added separately in step S20, or may be introduced as an iron source, a manganese source or an M source in step S10.
  • the calcined material may further include a first carbon source, and the amount of the first carbon source added satisfies: the first carbon source contains The mass of some carbon elements accounts for a percentage of the total mass of the roasting material that is greater than 0 and less than or equal to 25%; for example, it can be a value less than 0.001%, 0.001%, 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 10%, 15%, 20%, 25% and a value between any two of the above values.
  • the multiple first raw material components for preparing the first precursor contain organic anions, that is, the multiple first raw material components include one or more of organic iron salts, organic manganese salts and organic M salts
  • a carbon source may or may not be additionally added during the calcination in step S20.
  • the mass of the carbon element contained in the first carbon source accounts for a percentage of the total mass of the roasting material that is greater than 0 and less than or equal to 25%, wherein the mass of the carbon element contained in the first carbon source refers to the sum of the mass of the carbon element contained in multiple first raw material components and the mass of the carbon element in the additionally added carbon source.
  • the third precursor can be prepared from the second precursor.
  • the third precursor includes a core and a carbon coating layer coated on the outer surface of the core, and the material of the core includes a material with the general formula of Li a Mn x Fe y M z PO 4 , wherein M is a metal element, including but not limited to one or more elements of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum; a is 0.95-1.10, x is 0.10-0.95, y is 0.10-0.95, z is 0.01-0.10, and the sum of x, y and z is 0.95-1.06.
  • the carbon coating layer refers to a carbon layer coated on the outer surface of the core, which can be a continuous film layer that completely covers the core, or a discontinuous film layer that only covers part of the surface of the core.
  • the lithium source In the process of mixing the second precursor and the lithium source, the lithium source fully contacts the second precursor and gradually enters into the inner core to form a mixed phase, thereby obtaining a third precursor.
  • the mass of the carbon coating layer accounts for 1% to 5% of the mass of the third precursor, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% and values between any two of the above values.
  • step S30
  • the lithium source includes but is not limited to one or more of lithium oxide, lithium hydroxide, organic lithium salt and inorganic lithium salt.
  • the lithium oxide includes but is not limited to Li2O .
  • the inorganic lithium salt includes but is not limited to one or more of lithium carbonate, lithium sulfate, lithium nitrate, lithium dihydrogen phosphate and lithium phosphate.
  • the organic lithium salt includes But it is not limited to one or more of lithium acetate and lithium oxalate.
  • the surfactant includes, but is not limited to, one or both of PEG (polyethylene glycol) and ATMP (aminotrimethylphosphonic acid).
  • the molar ratio of the lithium element in the lithium source to the iron element in the iron source is (0.95-1.10): (0.10-0.95).
  • the added mass of the surfactant is 1 to 5 wt % of the mass of the iron source, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% and values between any two of the above values.
  • the plurality of second raw material components further include a phosphorus source, and the phosphorus source is added again to ensure an excess of the phosphorus source, thereby promoting sufficient reaction.
  • the third precursor has a carbon coating layer, and the carbon of the carbon coating layer is introduced when preparing the second precursor, and can also be introduced by a newly added carbon source.
  • the newly introduced carbon source is named as the second carbon source when preparing the third precursor.
  • the second carbon source includes but is not limited to one or more of an organic metal salt, an organic carbon source and an inorganic carbon source
  • the organic metal salt includes one or more of an organic iron salt, an organic manganese salt, an organic M source, and an organic lithium source
  • the organic carbon source includes one or more of glucose, sucrose, lactose, starch, organic acid, vitamins, polyvinyl pyrrolidone, polyethylene glycol, hydroxyethyl diphosphonic acid, aminotrimethylphosphonic acid, diacetate tetramine and phenolic resin
  • the inorganic carbon source includes one or more of graphene, carbon nanotubes and graphite.
  • the multiple second raw material components also include a second carbon source, and the mass of carbon elements in the multiple second carbon sources accounts for 1% to 25% of the total mass of the multiple second raw material components; for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 10%, 15%, 20%, 25% and values between any two of the above values.
  • the plurality of second raw material components may include a second carbon source or may not include the second carbon source.
  • the second carbon source is added, the total mass of the carbon contained in the second precursor and the carbon contained in the second carbon source accounts for 1 to 25% of the total mass of the plurality of second raw material components; for example, it may be 1%, 2%, 3%, 4%, 5%, 6%, 10%, 15%, 20%, 25% and values between any two of the above values.
  • the present application further proposes a positive electrode material, which can be prepared from the above precursor.
  • the positive electrode material includes an inner core and a carbon coating layer coated outside the inner core, wherein the material of the inner core includes a material of the general formula Li a Mn x Fe y M z PO 4 , wherein M is a metal element, including but not limited to one or more elements of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum; a is 0.95-1.10, x is 0.10-0.95, y is 0.10-0.95, z is 0.01-0.10, and the sum of x, y and z is 0.95-1.06.
  • M is a metal element, including but not limited to one or more elements of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc
  • the mass of the carbon coating layer accounts for 1% to 2% of the mass of the positive electrode material; for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2% and values between any two of the above values.
  • the positive electrode material has higher specific energy and better cycle performance.
  • the present application also provides a method for preparing a positive electrode material, the method comprising the following steps:
  • the general formula of the first precursor is Mn x Fe y M z PO 4 ⁇ nH 2 O, wherein x is 0.10 to 0.95, y is 0.10 to 0.95, z is 0.01 to 0.10, and the sum of x, y and z satisfies greater than or equal to 0.95 and less than or equal to 1.06.
  • the second precursor comprises a core of the general formula Mn x Fe y M z PO 4 , wherein M is a metal element, including but not limited to magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, One or more elements selected from beryllium, lanthanum and aluminum; x is 0.10 to 0.95, y is 0.10 to 0.95, z is 0.01 to 0.10, and the sum of x, y and z is 0.95 to 1.06.
  • the second precursor may be a precursor material without a carbon layer or a precursor material with a carbon layer, and in the second precursor, the mass of the carbon layer accounts for less than or equal to 5% of the mass of the second precursor.
  • the third precursor includes a core and a carbon coating layer coated on the outer surface of the core, wherein the material of the core includes a material of the general formula LiaMnxFeyMzPO4 , wherein M is a metal element, including but not limited to one or more elements of magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum; a is 0.95-1.10, x is 0.10-0.95, y is 0.10-0.95, z is 0.01-0.10, and the sum of x, y and z is 0.95-1.06.
  • the mass of the carbon coating layer accounts for 1%-5% of the mass of the third precursor.
  • step S200 an additional carbon source may be added in step S200 or step S300.
  • steps S100, S200 and S300 may be implemented with reference to the aforementioned steps S10, S20 and S30, which will not be described in detail herein.
  • step S400 may include: under the protection of an inert gas, heating the third precursor to 600-950° C. at a heating rate of 2-10° C., keeping the temperature for 5-24 hours, and cooling the precursor to room temperature under an inert atmosphere to obtain a positive electrode material.
  • the room temperature mentioned in this application refers to 20 to 40°C.
  • the embodiment of the present application also provides a positive electrode plate 100, as shown in Figure 6, the positive electrode plate 10 includes a positive electrode current collector 10 and a coating 20 disposed on one side of the positive electrode current collector 10, and the material of the coating 20 includes the positive electrode material described in any of the above embodiments.
  • the material of the positive electrode current collector 10 can be any common conductive metal material in the art, including but not limited to aluminum foil, platinum foil or palladium foil, and the present application does not limit this.
  • the embodiment of the present application also provides a lithium-ion battery 100, including but not limited to button batteries, soft-pack batteries, square lithium-ion batteries, cylindrical lithium-ion batteries, etc.
  • the lithium-ion battery includes the above The positive electrode sheet of any embodiment described in the above. Specifically, please refer to Figures 4 and 5.
  • the lithium-ion battery 200 includes an outer shell 1 and a core package 2.
  • the outer shell 1 is composed of a shell 11 and a shell cover 12.
  • a housing space is formed in the shell 11, and the core package 2 is installed in the housing space.
  • the core package 2 includes the positive electrode sheet 100, the separator 4 and the negative electrode sheet 3 stacked in sequence, wherein in the positive electrode sheet 100, the positive electrode collector 10 is arranged close to the separator 4, and the coating 20 is arranged on the side of the positive electrode collector 10 away from the separator 4; in addition, in some embodiments, the core package 2 also includes a positive electrode ear 51 connected to the positive electrode sheet 100 and a negative electrode ear 61 connected to the negative electrode sheet 3.
  • the core package 2 is filled with electrolyte.
  • the lithium-ion battery 200 also includes a positive electrode column 52 and a negative electrode column 62 arranged on the outer shell 1, wherein the positive electrode column 52 is arranged corresponding to the positive electrode ear 51, passes through the outer shell 1 and is connected to the positive electrode ear 51 through a first connecting piece 53, and the negative electrode column 62 is arranged corresponding to the negative electrode ear 61, passes through the outer shell 1 and is connected to the negative electrode ear 61 through a second connecting piece 63.
  • This embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content of the positive electrode material is 1.4%.
  • the molar ratio of manganese in manganese carbonate, iron in ferric phosphate, magnesium in magnesium oxide and phosphorus in phosphoric acid is 0.55:0.35:0.1:1; the molar ratio of hydrogen peroxide and iron in ferric phosphate is 2.5:1; and the added mass of HEDP is 0.5wt% of the mass of ferrous phosphate.
  • the first precursor is calcined at 550-750° C. to obtain a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 .
  • the carbon content of the second precursor is 0%.
  • the second precursor, sucrose, PEG, ATMP and lithium carbonate are mixed and ground to obtain a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C.
  • the carbon content of the third precursor is 3.5%.
  • the mass of carbon in sucrose accounts for 10% of the total mass of the second precursor, sucrose, PEG, ATMP and lithium carbonate.
  • the mass of carbon element in PEG accounts for 2% of the total mass of the second precursor, sucrose, PEG, ATMP and lithium carbonate, the mass ratio of lithium element in lithium carbonate to iron element in iron phosphate is 1.04:0.35, and the added mass of ATMP is 3wt% of the mass of iron phosphate.
  • the third precursor was heated to 800°C at a heating rate of 8°C, kept at this temperature for 10 h, and then cooled to room temperature under an inert atmosphere to obtain the positive electrode material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this embodiment, the iron phosphate is replaced by scrap iron, the manganese carbonate is replaced by manganese dioxide, and the sucrose is replaced by glucose. In addition, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, in this embodiment, the iron phosphate is changed to iron oxalate, the manganese dioxide is changed to manganese oxalate, and hydrogen peroxide is not added. In addition, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.1 Fe 0.75 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate to iron element in iron phosphate is changed to 0.1:0.75. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.95 Fe 0.1 Mg 0.01 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate, iron element in iron phosphate and magnesium element in magnesium oxide is changed to 0.95:0.1:0.01. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.1 Fe 0.95 Mg 0.01 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate, iron element in iron phosphate and magnesium element in magnesium oxide is changed to 0.1:0.95:0.01. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.4 Mg 0.05 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate, iron element in iron phosphate and magnesium element in magnesium oxide is changed to 0.55:0.4:0.05. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.38 Fe 0.5 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate to iron element in iron phosphate is changed to 0.38:0.5. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.7 Fe 0.3 Mg 0.05 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate, iron element in iron phosphate and magnesium element in magnesium oxide is changed to 0.7:0.3:0.05. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.57 Fe 0.3 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate to iron element in iron phosphate is changed to 0.57:0.3. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.3 Fe 0.58 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate to iron element in iron phosphate is changed to 0.3:0.58. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.39 Mg 0.05 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of the iron element in the iron phosphate and the magnesium element in the magnesium oxide is changed to 0.39:0.05. In addition, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.5 Fe 0.4 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of manganese element in manganese carbonate to iron element in iron phosphate is changed to 0.5:0.4. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.37 Mg 0.04 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of the iron element in the iron phosphate and the magnesium element in the magnesium oxide is changed to 0.37:0.04. In addition, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.37 Mg 0.07 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, the molar ratio of the iron element in the iron phosphate and the magnesium element in the magnesium oxide is changed to 0.37:0.07. In addition, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as embodiment 1, except that this embodiment provides a manganese phosphate
  • the iron-lithium material is Li 0.95 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • the mass ratio of lithium element in lithium carbonate to iron element in iron phosphate is 0.95:0.35. Apart from this, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.1 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (3) of this embodiment, the mass ratio of lithium element in lithium carbonate to iron element in iron phosphate is 1.1:0.35. In addition, other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Co 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, magnesium oxide is replaced by cobalt oxide. Other than that, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Ca 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, magnesium oxide is replaced by calcium oxide. Other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Sc 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, magnesium oxide is replaced by scandium oxide. Other than that, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as the embodiment 1, except that this embodiment provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Cr 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in step (1) of this embodiment, magnesium oxide is replaced by chromium oxide. Other than that, the other parameters and steps remain unchanged.
  • This embodiment is basically the same as embodiment 1, except that this embodiment provides a manganese phosphate
  • the iron lithium material is Li 1.04 Mn 0.55 Fe 0.35 V 0.1 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • magnesium oxide is replaced by vanadium oxide. Apart from this, other parameters and steps remain unchanged.
  • This embodiment is basically the same as Embodiment 1, except that this embodiment provides a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 1%, and a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 3%. Accordingly, lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C can be prepared, and the carbon content in the positive electrode material is 1.4%.
  • steps (2) and (3) are changed to:
  • the first precursor and PEG are calcined at 550-750° C. to obtain a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, wherein the mass of the carbon element in PEG accounts for 4% of the total mass of the first precursor and PEG.
  • the second precursor, sucrose, PEG, ATMP and lithium carbonate are mixed and ground to obtain a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C; wherein the added mass of sucrose accounts for 8% of the total mass of the second precursor, sucrose, PEG and ATMP, the added mass of PEG accounts for 2% of the total mass of the second precursor, sucrose, PEG and ATMP, the mass ratio of lithium element in lithium carbonate to iron element in iron phosphate is 1.04:0.35, and the added mass of ATMP is 3wt% of the mass of iron phosphate.
  • This embodiment is basically the same as Embodiment 1, with the only difference being that this embodiment provides a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 5%, and a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 3%. Accordingly, lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C can be prepared, and the carbon content in the positive electrode material is 2%.
  • steps (2) and (3) are changed to:
  • the first precursor and PEG are calcined at 550-750° C. to obtain a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, wherein the mass of the carbon element in PEG accounts for 5% of the total mass of the first precursor and PEG.
  • This embodiment is basically the same as Embodiment 1, except that this embodiment provides a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 5.5%, and a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 6%. Accordingly, lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C can be prepared, and the carbon content in the positive electrode material is 3%.
  • steps (2) and (3) are changed to:
  • the first precursor and PEG are calcined at 550-750° C. to obtain a second precursor Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, wherein the mass of the carbon element in PEG accounts for 17% of the total mass of the first precursor and PEG.
  • the second precursor, sucrose, PEG, ATMP and lithium carbonate are mixed and ground to obtain a third precursor Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C; wherein the mass of the carbon element in sucrose accounts for 3% of the total mass of the second precursor, sucrose, PEG and ATMP, the mass of the carbon element in PEG accounts for 1% of the total mass of the second precursor, sucrose, PEG and ATMP, the mass ratio of the lithium element in lithium carbonate to the iron element in iron phosphate is 1.04:0.35, and the added mass of ATMP is 3wt% of the mass of iron phosphate.
  • This comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.1 PO 4 @C, in which the carbon content is 1.4%.
  • the lithium manganese iron phosphate material of this comparative example is prepared by the following preparation method:
  • Lithium carbonate, manganese carbonate, iron phosphate, magnesium oxide, phosphoric acid, and graphite are mixed and ground, then calcined under nitrogen protection, and cooled to room temperature under an inert atmosphere to obtain a positive electrode material.
  • This comparative example is basically the same as comparative example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Co 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this comparative example, magnesium oxide is replaced by cobalt oxide. Other than that, other parameters and steps remain unchanged.
  • This comparative example is basically the same as comparative example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Ca 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this comparative example, magnesium oxide is replaced by calcium oxide. Other parameters and steps remain unchanged.
  • This comparative example is basically the same as comparative example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Sc 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this comparative example, magnesium oxide is replaced by scandium oxide. Other than that, other parameters and steps remain unchanged.
  • This comparative example is basically the same as comparative example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Cr 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this comparative example, magnesium oxide is replaced by chromium oxide. Other than that, other parameters and steps remain unchanged.
  • This comparative example is basically the same as comparative example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 V 0.1 PO 4 @C, the carbon content in the positive electrode material is 1.4%, and in this comparative example, magnesium oxide is replaced by vanadium oxide. Other than that, other parameters and steps remain unchanged.
  • This comparative example is substantially the same as Example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.35 Mg 0.11 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • the molar ratio of manganese element in manganese dioxide, iron element in scrap iron, magnesium element in magnesium oxide and phosphorus element in phosphoric acid is changed to 0.55:0.35:0.11:1.
  • This comparative example is substantially the same as Example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.55 Fe 0.45 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • step (1) of the preparation method of this comparative example magnesium oxide is not added.
  • This comparative example is substantially the same as Example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.96 Fe 0.1 Mg 0.01 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • step (1) of the preparation method of this comparative example the molar ratio of manganese in manganese dioxide, iron in scrap iron, magnesium in magnesium oxide and phosphorus in phosphoric acid is changed to 0.96:0.1:0.01:1.
  • This comparative example is substantially the same as Example 1, except that this comparative example provides a lithium manganese iron phosphate material Li 1.04 Mn 0.1 Fe 0.96 Mg 0.01 PO 4 @C, and the carbon content in the positive electrode material is 1.4%.
  • step (1) of the preparation method of this comparative example the molar ratio of manganese in manganese dioxide, iron in scrap iron, magnesium in magnesium oxide and phosphorus in phosphoric acid is changed to 0.1:0.96:0.01:1.
  • the lithium manganese iron phosphate materials prepared in the above examples and comparative examples were used to prepare batteries and perform performance tests.
  • positive electrode sheet The corresponding positive electrode active material (i.e., the lithium manganese iron phosphate material prepared in the embodiment and the comparative example), the conductive agent acetylene black and the binder polyvinylidene fluoride are mixed in a weight ratio of 96:2:2, and N-methylpyrrolidone is used as a solvent. After fully grinding and stirring, a uniform positive electrode slurry is formed; the slurry is coated on the positive electrode current collector aluminum foil, and then dried and cold pressed to obtain a positive electrode sheet.
  • the corresponding positive electrode active material i.e., the lithium manganese iron phosphate material prepared in the embodiment and the comparative example
  • the conductive agent acetylene black and the binder polyvinylidene fluoride are mixed in a weight ratio of 96:2:2, and N-methylpyrrolidone is used as a solvent. After fully grinding and stirring, a uniform positive electrode slurry is formed; the slurry is coated on the positive electrode current collector
  • the battery cycle charge and discharge life test was carried out under 1C-1C charge and discharge conditions.
  • the number of cycles that the battery can achieve was recorded as 25°C 1C-1C cycle number @80%;
  • the battery cycle charge and discharge life test was carried out under 1C-1C charge and discharge conditions.
  • the number of cycles that the battery can achieve was recorded as 45°C 1C-1C cycle number @80%.
  • Example 1 has a better charge-discharge specific energy and cycle number than Comparative Example 1
  • Example 18 has a better charge-discharge specific energy and cycle number than Comparative Example 2
  • Example 19 has a better charge-discharge specific energy and cycle number than Comparative Example 3
  • Example 20 has a better charge-discharge specific energy and cycle number than Comparative Example 4
  • Example 21 has a better charge-discharge specific energy and cycle number than Comparative Example 5
  • Example 22 has a better charge-discharge specific energy and cycle number than Comparative Example 6, indicating that compared with the conventional pure solid phase method, the present application adopts a liquid-solid phase method to synthesize materials and prepares precursors of different stages by graded preparation, and accurately controls the structure of each precursor, which can significantly improve the specific energy and cycle number of the positive electrode material;
  • Example 1 Compared with Comparative Example 8, Example 1 has significantly higher charge and discharge specific energy and cycle number, indicating that the addition of doped metal elements into the positive electrode material in the present application helps to improve the cycle performance and specific energy of the positive electrode material;
  • Comparative Example 7 is compared with Example 1
  • Comparative Example 9 is compared with Example 5
  • Comparative Example 10 is compared with Example 6.
  • Each example has a significantly higher charge and discharge specific energy and cycle number, indicating that there is a specific molar ratio range between the elements in the precursor. When the molar ratio of each element is within this range, the prepared positive electrode material has good cycle performance and specific energy. Further optimizing the molar ratio of the elements so that it falls within the preferred range is helpful to further improve the cycle performance and specific energy of the positive electrode material; when the molar ratio of one of the elements exceeds the range, the cycle performance or specific energy of the material will decrease;
  • the batteries of Examples 23 and 24 have higher charge and discharge specific energy and cycle times, indicating that regulating the carbon content in the precursor helps to better regulate the performance of the positive electrode material.
  • the carbon content of the precursor exceeds the control range (carbon content is less than or equal to 5%), the material's cycle performance or specific energy will decrease.

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Abstract

一种前驱体的制备方法，包括以下步骤：提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体，所述第一前驱体的通式为MnxFeyMzPO 4·nH 2O；其中，M为金属元素，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，n为0～10任意整数；根据该前驱体制备得到的正极材料、正极极片及锂离子电池。

Description

前驱体及其制备方法、正极材料、正极极片及锂离子电池
本申请要求在2023年11月15日提交中国专利局、申请号为202311538600.9的中国专利申请的优先权，以上申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及电极材料技术领域，具体涉及一种前驱体及其制备方法、正极材料、正极极片及锂离子电池。
背景技术
正极材料是对锂离子电池的性能具有重要影响，是提高电池性能的重要掣肘。磷酸锰铁锂是新一代锂离子电池正极材料，在充放电过程中结构稳定，具有较高的工作电压、较高的能量密度以及良好的安全性。
相关技术中，磷酸锰铁锂材料的性能受其合成路线的影响，存在循环性能差、比能量低的问题，影响了材料的应用。
技术问题
本申请提供一种前驱体及其制备方法、正极材料、正极极片及锂离子电池来解决上述技术问题。
技术解决方案
第一方面，本申请实施例提供了一种前驱体的制备方法，包括以下步骤：
提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O；
其中，M为金属元素，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，n为0～10任意整数。
第二方面，本申请实施例提供了一种前驱体，所述前驱体包括第一前驱体、第二前驱体和第三前驱体中的任意一种：
所述第一前驱体的通式为MnxFeyMzPO4·nH2O；
所述第二前驱体包括通式为MnxFeyMzPO4的核；
所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料；
其中，M为金属元素，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，a为0.95～1.10，n为0～10任意整数。
第三方面，本申请实施例提供了一种正极材料，所述正极材料由前驱体制备得到，所述前驱体包括上文所述的制备方法制得的前驱体，或者，上文所述的前驱体。
第四方面，本申请的实施例提供了一种正极极片，包括正极集流体以及设置在所述正极集流体一侧的涂层，所述涂层的材料包括上文所述的正极材料。
第五方面，本申请的实施例提供了一种锂离子电池，包括如上文所述的正极极片。
有益效果
本申请的有益效果：
在本申请的实施例提供了一种用于制备磷酸锰铁锂材料的前驱体，通过优化前驱体的元素配比，可以更好地调控磷酸锰铁锂材料的特性，改善磷酸锰铁锂的比能量低以及循环性能差的技术问题。
附图说明
图1是本申请的一实施例提供的前驱体的制备方法的流程示意图；
图2是本申请的另一实施例提供的前驱体的制备方法的流程示意图；
图3是本申请的又一实施例提供的前驱体的制备方法的流程示意图；
图4是本申请一实施例提供的锂离子电池的结构示意图；
图5是图4中芯包的结构示意图；
图6是图5中正极极片的结构示意图；
附图标记说明：100-正极极片；10-正极集流体；20-涂层；200-锂离子电池；1-外壳；11-壳体；12-壳盖；2-芯包；3-负极极片；4-隔膜；51-正极耳；52-正极柱；53-第一连接片；61-负极耳；62-负极柱；63-第二连接片。
本发明的实施方式
除非另行定义，文中所使用的所有专业与科学用语与本领域技术人员所熟悉的意义相同，并且本申请实施例和对比例中所用的材料或试剂可商购获得。此外，任何与所记载内容相似或均等的方法及材料皆可应用于本申请中。文中所述的较佳实施方法与材料仅作示范之用，但不能限制本申请的内容。
需说明的是，以下实施例的描述顺序不作为对实施例优选顺序的限定。本申请的各个实施例可以以一个范围的型式存在；应当理解，以一范围型式的描述仅仅是因为方便及简洁，不应理解为对本申请范围的硬性限制；因此，应当认为所述的范围描述已经具体公开所有可能的子范围以及该范围内的单一数值。例如，应当认为从1到6的范围描述已经具体公开子范围，例如从1到3，从1到4，从1到5，从2到4，从2到6，从3到6等，以及所数范围内的单一数字，例如1、2、3、4、5及6，此不管范围为何皆适用。另外，每当在本文中指出数值范围，是指包括所指范围内的任何引用的数字(分数或整数)。
在本申请的描述中，术语“包括”是指“包括但不限于”。
术语“多种”、“多次”或其类似表达指的是两种(次)或两种(次)以上，例如可以是两种(次)、三种(次)、四种(次)、五种(次)、六种(次)等。
术语“和/或”的选择范围包括两个或两个以上相关所列项目中任一个项目，也包括相关所列项目的任意的和所有的组合，所述任意的和所有的组合包括任意的两个相关所列项目、任意的更多个相关所列项目、或者全部相关所列项目的组合。比如，“A和/或B”包括A、B以及A+B三种并列方案。又比如，“A，及/或，B，及/或，C，及/或，D”的技术方案，包括A、B、C、D中任一项(也即均用“逻辑或”连接的技术方案)，也包括A、B、C、D的任意的和所有的组合，也即包括A、B、C、D中任两项或任三项的组合，还包括A、B、C、D的四项组合(也即均用“逻辑与”连接的技术方案)。
术语“固含量”是指浆料中固形物的质量占浆料的总质量的比例。
本申请实施例提出一种前驱体及其制备方法，所述前驱体可以是第一前驱 体MnxFeyMzPO4·nH2O，也可以是第二前驱体，所述第二前驱体包括通式为MnxFeyMzPO4的核，还可以是第三前驱体，所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料，上述所述前驱体可以用于制备磷酸锰铁锂正极材料。
所述前驱体中Mn、Fe元素均匀形成固溶体，有效避免元素偏析，且前驱体中各元素占比经过优化而处于较佳的比例范围内，采用所述前驱体可以更好地调控磷酸锰铁锂正极材料的特性，制备出结构稳定、离子通道畅通、且具有较高的比能量和较长的循环的正极材料，所述正极材料包括内核以及包覆在内核外表面的碳包覆层，所述内核具有如下通式：LiaMnxFeyMzPO4。所述正极材料的具体特征将在后文详细描述，此处暂且不提。
如图1所示，本申请实施例提出一种第一前驱体的制备方法，所述制备方法包括以下步骤：
S10，提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O。
如图2所示，本申请实施例提出一种第二前驱体的制备方法，所述制备方法包括以下步骤：
S10，提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O。
S20，提供焙烧料，所述焙烧料包括所述第一前驱体，将所述焙烧料进行焙烧，得到第二前驱体，所述第二前驱体包括通式为MnxFeyMzPO4的核。
如图3所示，本申请实施例提出一种第三前驱体的制备方法，所述制备方法包括以下步骤：
S10，提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前 驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O。
S20，提供焙烧料，所述焙烧料包括所述第一前驱体，将所述焙烧料进行焙烧，得到第二前驱体，所述第二前驱体包括通式为MnxFeyMzPO4的核。
S30，提供多个第二原料组分，所述多个第二原料组分包括所述第二前驱体、锂源和表面活性剂，将所述多个第二原料组分混合，干燥，得到第三前驱体，所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料。
基于步骤S10，可以制备出第一前驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O。其中，x为0.10～0.95，例如可以为0.10、0.12、0.15、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、0.91、0.93、0.95以及上述任意两个值之间的值；y为0.10～0.95，例如可以为0.10、0.12、0.15、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、0.91、0.93、0.95以及上述任意两个值之间的值；z为0.01～0.10，例如可以为0.01、0.02、0.03、0.04、0.05、0.06、0.07、0.08、0.09、0.10以及上述任意两个值之间的值。进一步地，在一些实施例中，x、y及z的和满足大于等于0.95且小于等于1.06；例如，x+y+z可以为0.95、0.96、0.97、0.98、0.99、1.00、1.01、1.02、1.03、1.04、1.05、1.06以及上述任意两个值之间的值。其中，n为0～10任意整数，例如可以是0、1、2、3、4、5、6、7、8、9或者10。
进一步地，在一些实施例中，x为0.40～0.70，精确控制Mn元素的摩尔占比范围满足以上条件时，有利于平衡磷酸锰铁锂正极材料的比能量和循环性能，以获取兼具高比能量和高循环性能的正极材料。更进一步地，x为0.50～0.60，在此范围内，有助于进一步提高比能量和循环性能。
进一步地，在一些实施例中，y为0.30～0.60，精确控制Fe元素的摩尔占比范围满足以上条件时，有利于平衡磷酸锰铁锂正极材料的比能量和循环性能，以获取兼具高比能量和高循环性能的正极材料。更进一步地，y为0.50～0.60，在此范围内，有助于进一步提高循环性能。
更进一步地，在一些实施例中，x与y的比值为0.9～1.1时，有助于进一步提升循环性能。
进一步地，在一些实施例中，z为0.05～0.10，精确控制M元素的摩尔占比范围满足以上条件时，有利于平衡磷酸锰铁锂正极材料的比能量和循环性能，以获取兼具高比能量和高循环性能的正极材料。更进一步地，z为0.05～0.07，在此范围内，有助于进一步提高比能量和循环性能。
进一步地，在一些实施例中，x、y及z的和为0.96～0.99。精确控制各个元素的摩尔比范围满足以上条件时，有利于平衡磷酸锰铁锂正极材料的比能量和循环性能，以获取兼具高比能量和高循环性能的正极材料。
在一些实施例中，n为0或1或2。
M代表掺杂金属元素，通过掺杂M金属元素，有助于改善正极材料中锂离子扩散通道，进而提高正极材料的电导率，此外，掺杂金属元素M可以和氧形成更稳定的晶格骨架，进而加强结构的稳定性，有助于提高倍率性能、循环稳定性及能量密度。在一些实施例中，所述M元素包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素；可以理解，M可以是一种元素，也可以是两种、三种或者三种以上的元素。M所包含的金属元素中，一部分的金属元素的磷酸盐具有橄榄石结构，例如当M为镍元素或者钴元素时，或者M为镍元素和钴元素时，M元素的磷酸盐与磷酸锰或者磷酸铁均配置为橄榄石结构，从而构成多元橄榄石系正极材料，多元橄榄石系正极材料的充放电曲线、循环性能曲线可以看作每种金属元素的磷酸盐所构成的橄榄石结构的充放电曲线、循环性能曲线的线性叠加，进而有效提升正极材料的循环性能。
回到步骤S10中：
所述铁源是指用于提供铁元素的原料化合物，可以是本领域常用于正极材料制备的、含有铁元素的任意化合物，例如可以包括但不限于铁粉、无机铁盐及有机铁盐中的一种或多种，其中，所述无机铁盐包括硫酸亚铁、磷酸铁、磷 酸氢铁、磷酸二氢铁中的一种或多种，所述有机铁盐包括乙酸铁、草酸亚铁、酒石酸亚铁、乳酸亚铁、甲酸亚铁中的一种或多种。
所述锰源是指用于提供锰元素的原料化合物，可以是本领域常用于正极材料制备的、含有锰元素的任意化合物，例如可以包括但不限于无机锰盐和有机锰盐中的一种或多种，所述无机锰盐包括硫酸锰、碳酸锰、硝酸锰、磷酸锰、磷酸氢锰中的一种或多种，所述有机锰盐包括醋酸锰、草酸锰中的一种或多种。
所述M源是指用于提供M元素的原料化合物，可以是本领域常用于正极材料制备的、含有M元素的任意化合物，例如可以包括但不限于有机M盐和无机M盐中的一种或多种，所述有机M盐包括M元素的甲酸盐、M元素的乙酸盐、M元素的羟乙酸盐、M元素的乳酸盐、M元素的酒石酸盐、M元素的草酸盐中的一种或多种，所述无机M盐包括M元素的磷酸盐、M元素的磷酸氢盐、M元素的磷酸二氢盐、M元素的碳酸盐、M元素的氧化物、M元素的氢氧化物、M元素的氟化物、M元素的氯化物、M元素的硝酸盐、M元素的硫酸盐、M元素的溴化物中的至少一种，其中，M元素包括镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种。可以理解，M源中可以含有一种金属元素，也可以含有两种或者两种以上的元素。
所述磷源是指用于提供磷元素的原料化合物，包括但不限于磷酸、磷酸二氢铵中的一种或两种。可以理解，在一些实施例中，多个第一原料组分中，所采用的铁源、锰源、M源等化合物中也含有磷元素时，该化合物也可以作为磷源。
铁源、锰源、磷源、M源以及双氧水通过混合充分接触，形成混合相。
为了制备出具有较佳元素配比的第一前驱体，在一些实施例中，所述锰源中的锰元素、所述铁源中的铁元素、所述M源中的M元素以及所述磷源中的磷元素的摩尔比为(0.10～0.95)：(0.10～0.95)：(0.01～0.10)：1，如此可以调控第一前驱体中各元素的摩尔比，制得MnxFeyMzPO4·nH2O。
在一些实施例中，所述双氧水和所述铁源中铁元素的摩尔比为(2～3)：1，例如可以为2:1、2.1:1、2.2:1、2.3:1、2.4:1、2.5:1、2.6:1、2.7:1、2.8:1、2.9:1、3:1以及上述任意两个值之间的值。
在一些实施例中，所述多个第一原料组分还包括络合剂，所述络合剂包括HEDP(羟乙基二膦酸)、ATMP(氨基三甲膦酸)及DTPA(二乙酸四胺)中的一种或多种。所述络合剂的添加质量为铁源的质量的0.1～1wt％，例如可以为0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％以及上述任意两个值之间的值。
在一些实施例中，将所述多个第一原料组分混合，干燥，得到第一前驱体的步骤包括：将所述多个第一原料组分混合，在60～95℃温度条件下进行加热，然后对反应产物进行过滤，取固相物在100～150℃下进行干燥，得到第一前驱体。
所述第二前驱体可以由第一前驱体焙烧得到。所述第二前驱体包括通式为MnxFeyMzPO4的核，其中，M为金属元素，包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素；x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06。
所述第二前驱体可以为没有碳层的前驱体材料，具体的，所述第二前驱体为通式为MnxFeyMzPO4的材料，所述第二前驱体中碳含量为0；所述第二前驱体也可以为具有碳层的前驱体材料，具体的，所述第二前驱体包括核以及附着在所述核表面的碳层，所述核包括通式为MnxFeyMzPO4的材料，所述第二前驱体中，所述碳层的质量占所述第二前驱体的质量的百分比小于等于5％，例如可以为大于0且小于0.01％的值、0.01％、0.05％、0.1％、0.5％、1％、1.5％、2％、2.5％、3％、4％、5％以及上述任意两个值之间的值。通过在核外表面附着碳层，并控制其质量含量在上述范围内，一方面可以在制备正极材料的过程中起到保护作用，有助于防止材料过度氧化，减少副反应，提高产物的纯度，另一方面，还可以有效调控晶体长大速率和反应均匀性，使晶体各处均匀生长， 并抑制晶体颗粒团聚或粘连，有助于获得尺寸更均匀、离子电导率更高、性能更稳定的产物；此外，采用第二前驱体制得的正极材料制备电池，有助于提高电池导电性。可以理解，所述碳层是指附着在核外表面上的碳，其可以是连续且完全包覆住核的膜层，也可以是不连续的、只包覆了核的部分表面的膜层。
步骤S20中：
在一些实施例中，焙烧的温度可以为550～750℃，例如可以为550℃、560℃、580℃、600℃、620℃、650℃、670℃、690℃、700℃、710℃、730℃、750℃以及上述任意两个值之间的值。
在一些实施例中，所述第二前驱体具有碳层。为了形成碳层，需要提供碳元素的化合物，本申请将第二前驱体中碳层的碳元素来源的化合物命名为第一碳源。所述第一碳源包括有机金属盐、有机碳源以及无机碳源中的一种或多种，所述有机金属盐包括有机铁盐、有机锰盐、有机M源中的一种或多种，所述有机碳源包括葡萄糖、蔗糖、乳糖、淀粉、有机酸、维生素、聚乙烯吡咯烷酮(PVP)、聚乙二醇(PEG)、羟乙基二膦酸、氨基三甲膦酸、二乙酸四胺以及酚醛树脂中的一种或多种，所述无机碳源包括石墨烯、碳纳米管以及石墨中的一种或多种。其中，有机金属盐由金属阳离子和有机阴离子组成，由于有机阴离子含有碳元素，其在惰性气体保护下焙烧时也可以形成碳层，因此可以作为碳源使用。
具体的，步骤S20可以按照如下步骤实施：提供焙烧料，将所述焙烧料在惰性气体的保护下进行焙烧，得到第二前驱体。其中，所述惰性气体包括氮气、氩气、氦气中的一种或多种。
所述第一碳源可以在步骤S20中另行添加，也可以在步骤S10中作为铁源、锰源或M源时引入。
当制备第一前驱体的多个第一原料组分中不含有有机阴离子，也即多个第一原料组分包括铁粉或无机铁盐、无机锰盐以及无机M盐时，步骤S20中，焙烧料还可以包括第一碳源，且所述第一碳源的添加量满足：所述第一碳源含 有的碳元素的质量占焙烧料的总质量的百分比大于0且小于等于25％；例如可以是小于0.001％的值、0.001％、0.1％、1％、2％、3％、4％、5％、6％、10％、15％、20％、25％以及上述任意两个值之间的值。
当制备第一前驱体的多个第一原料组分中含有有机阴离子时，也即多个第一原料组分包括有机铁盐、有机锰盐以及有机M盐中的一种或多种时，在进行步骤S20的焙烧时，可以额外掺入碳源，也可以不额外掺入碳源。
实际应用时，无论是否额外掺入碳源，原料的投料量需满足：所述第一碳源含有的碳元素的质量占焙烧料的总质量的百分比大于0且小于等于25％，其中，第一碳源含有的碳元素的质量是指多个第一原料组分中含有的碳元素的质量以及额外添加的碳源中碳元素的质量的总和。
所述第三前驱体可以由第二前驱体制备得到。所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料，其中，M为金属元素，包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素；a为0.95～1.10，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06。可以理解，所述碳包覆层是指包覆在内核外表面上的碳层，其可以是连续且完全包覆住内核的膜层，也可以是不连续的、只包覆了内核的部分表面的膜层。在将第二前驱体和锂源混合的过程中，锂源与第二前驱体充分接触，并逐步进入到内核中形成混合相，得到第三前驱体。
所述第三前驱体中，所述碳包覆层的质量占所述第三前驱体的质量的百分比为1％～5％，例如可以为1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％以及上述任意两个值之间的值。
步骤S30中：
所述锂源包括但不限于锂的氧化物、氢氧化锂、有机锂盐以及无机锂盐中的一种或多种，锂的氧化物包括但不限于是Li2O，无机锂盐包括但不限于碳酸锂、硫酸锂、硝酸锂、磷酸二氢锂、磷酸锂中的一种或多种，有机锂盐包括 但不限于乙酸锂、草酸锂中的一种或多种。
所述表面活性剂包括但不限于PEG(聚乙二醇)、ATMP(氨基三甲膦酸)中的一种或两种。
在一些实施例中，所述锂源中的锂元素和所述铁源中的铁元素的摩尔比为(0.95～1.10)：(0.10～0.95)。
在一些实施例中，所述表面活性剂的添加质量为铁源的质量的1～5wt％，例如可以为1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％以及上述任意两个值之间的值。
在一些实施例中，所述多个第二原料组分还包括磷源，通过再次添加磷源，以确保磷源过量，从而促进反应充分。
所述第三前驱体具有碳包覆层，所述碳包覆层的碳在制备第二前驱体时引入，也可以通过新添加的碳源引入。本申请将制备第三前驱体时，新引入的碳源命名为第二碳源。所述第二碳源包括但不限于有机金属盐、有机碳源以及无机碳源中的一种或多种，所述有机金属盐包括有机铁盐、有机锰盐、有机M源、有机锂源中的一种或多种，所述有机碳源包括葡萄糖、蔗糖、乳糖、淀粉、有机酸、维生素、聚乙烯吡咯烷酮、聚乙二醇、羟乙基二膦酸、氨基三甲膦酸、二乙酸四胺以及酚醛树脂中的一种或多种，所述无机碳源包括石墨烯、碳纳米管以及石墨中的一种或多种。
当第二前驱体含有的碳元素的质量百分比为0时，所述多个第二原料组分还包括第二碳源，且所述多个第二碳源中碳元素的质量占所述多个第二原料组分的总质量的百分比为1～25％；例如可以是1％、2％、3％、4％、5％、6％、10％、15％、20％、25％以及上述任意两个值之间的值。
当第二前驱体含有的碳元素的质量百分比大于0且小于等于5％时，所述多个第二原料组分可以包括第二碳源，也可以不包括第二碳源，当添加第二碳源时，第二前驱体含有的碳元素以及第二碳源含有的碳元素的总质量占多个第二原料组分的总质量的百分比为1～25％；例如可以是1％、2％、3％、4％、5％、 6％、10％、15％、20％、25％以及上述任意两个值之间的值。
本申请进一步提出一种正极材料，所述正极材料可以由上述前驱体制备得到。
所述正极材料包括内核以及包覆在内核外的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料，其中，M为金属元素，包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素；a为0.95～1.10，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06。所述碳包覆层的质量占所述正极材料的质量的百分比为1％～2％；例如可以为1％、1.1％、1.2％、1.3％、1.4％、1.5％、1.6％、1.7％、1.8％、1.9％、2％以及上述任意两个值之间的值。所述正极材料具有较高的比能量以及较佳的循环性能。
本申请实施例还提出一种正极材料的制备方法，所述制备方法包括以下步骤：
S100，提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体；
S200，提供焙烧料，所述焙烧料包括所述第一前驱体，将所述焙烧料进行焙烧，得到第二前驱体；
S300，提供多个第二原料组分，所述多个第二原料组分包括所述第二前驱体、锂源和表面活性剂，将所述多个第二原料组分混合，干燥，得到第三前驱体，所述第三前驱体。
S400，在惰性气体保护下，将所述第三前驱体焙烧，得到正极材料。
所述第一前驱体的通式为MnxFeyMzPO4·nH2O；其中，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和满足大于等于0.95且小于等于1.06。
所述第二前驱体包括通式为MnxFeyMzPO4的核，其中，M为金属元素，包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、 铍、镧以及铝中的一种或多种元素；x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06。所述第二前驱体可以为没有碳层的前驱体材料，也可以为具有碳层的前驱体材料，且所述第二前驱体中，所述碳层的质量占所述第二前驱体的质量的百分比小于等于5％。
所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料，其中，M为金属元素，包括但不限于镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素；a为0.95～1.10，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06。所述第三前驱体中，所述碳包覆层的质量占所述第三前驱体的质量的百分比为1％～5％。
通过分级制备不同阶段的前驱体，并精确调控各前驱体结构，可以有效制备出结构稳定、离子通道畅通，具有较高的比能量、较长的循环的正极材料。
可以理解，根据待制备的前驱体中碳含量的需求，可以在步骤S200或步骤S300中额外添加碳源。具体的，步骤S100、S200以及S300可以参考前述的步骤S10、S20以及S30实施，在此不作赘述。
具体的，步骤S400可以包括：在惰性气体保护下，将第三前驱体以2～10℃的升温速率升温至600～950℃，保温5～24h后，在惰性气氛下冷却至室温，得到正极材料。
本申请所述的室温是指20～40℃。
本申请的实施例还提供一种正极极片100，如图6所示，所述正极极片10包括正极集流体10以及设置在所述正极集流体10一侧的涂层20，所述涂层20的材料包括如前文中任意实施例所述的正极材料。具体的，正极集流体10的材料可以是本领域任意常见的导电金属材料，包括但不限于是铝箔、铂箔或钯箔，对此，本申请不作限制。
本申请的实施例还提供一种锂离子电池100，包括但不限于是扣式电池、软包电池、方形锂离子电池、圆柱形锂离子电池等等。锂离子电池包括如前文 中任意实施例所述的正极极片。具体来说，请参阅图4和图5，在一些实施例中，所述锂离子电池200包括外壳1和芯包2，外壳1由壳体11和壳盖12组成，壳体11内形成容纳空间，芯包2安装在容纳空间内。所述芯包2包括依次层叠设置的所述正极极片100、隔膜4和负极极片3，其中，正极极片100中，正极集流体10靠近隔膜4设置，涂层20设于正极集流体10背离隔膜4的一侧；此外，在一些实施例中，芯包2还包括与正极极片100连接的正极耳51以及与负极极片3连接的负极耳61。芯包2中填充有电解质。此外，锂离子电池200还包括设于外壳1的正极柱52和负极柱62，其中，正极柱52对应正极耳51设置，且穿过外壳1并通过第一连接片53与正极耳51连接，负极柱62对应负极耳61设置，且穿过外壳1并通过第二连接片63与负极耳61连接。
实施例1
本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％。
本实施例磷酸锰铁锂材料采用如下制备方法制备得到：
(1)将磷酸铁、磷酸、碳酸锰、氧化镁进行混合，缓慢加入双氧水、HEDP，然后，在80℃温度条件下进行加热，然后对反应产物进行过滤，取固相物在120℃下进行干燥，得到第一前驱体Mn0.55Fe0.35Mg0.1PO4·nH2O，n为0。其中，碳酸锰中锰元素、磷酸铁中铁元素、氧化镁中镁元素以及磷酸中磷元素的摩尔比为0.55:0.35:0.1:1；双氧水和磷酸铁中铁元素的摩尔比为2.5:1；HEDP的添加质量为磷酸铁的质量的0.5wt％。
(2)在氮气保护下，将第一前驱体在550～750℃下焙烧，得到第二前驱体Mn0.55Fe0.35Mg0.1PO4，第二前驱体中，碳含量为0％。
(3)将第二前驱体、蔗糖、PEG、ATMP和碳酸锂进行混合研磨得到第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C，第三前驱体中，碳含量为3.5％；其中，蔗糖中碳元素的质量占第二前驱体、蔗糖、PEG、ATMP和碳酸锂总质量的10％， PEG中碳元素的质量占第二前驱体、蔗糖、PEG、ATMP和碳酸锂总质量的2％，碳酸锂中锂元素和磷酸铁中铁元素的质量比为1.04:0.35，ATMP的添加质量为磷酸铁的质量的3wt％。
(4)在惰性气体保护下，将第三前驱体以8℃的升温速率升温至800℃，保温10h后，在惰性气氛下冷却至室温，得到正极材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C。
实施例2
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例中，磷酸铁改为废铁，碳酸锰改为二氧化锰，蔗糖改为葡萄糖。除此之外，其它参数和步骤均不变。
实施例3
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例中，磷酸铁改为草酸铁，二氧化锰改为草酸锰，不添加双氧水。除此之外，其它参数和步骤均不变。
实施例4
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.1Fe0.75Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素的摩尔比改为0.1:0.75。除此之外，其它参数和步骤均不变。
实施例5
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.95Fe0.1Mg0.01PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.95:0.1:0.01。除此之外，其它参数和步骤均不变。
实施例6
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.1Fe0.95Mg0.01PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.1:0.95:0.01。除此之外，其它参数和步骤均不变。
实施例7
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.4Mg0.05PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.55:0.4:0.05。除此之外，其它参数和步骤均不变。
实施例8
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.38Fe0.5Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素的摩尔比改为0.38:0.5。除此之外，其它参数和步骤均不变。
实施例9
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.7Fe0.3Mg0.05PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.7:0.3:0.05。除此之外，其它参数和步骤均不变。
实施例10
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.57Fe0.3Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素的摩尔比改为0.57:0.3。除此之外，其它参数和步骤均不变。
实施例11
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.3Fe0.58Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素的摩尔比改为0.3:0.58。除此之外，其它参数和步骤均不变。
实施例12
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.39Mg0.05PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.39:0.05。除此之外，其它参数和步骤均不变。
实施例13
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.5Fe0.4Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，碳酸锰中锰元素、磷酸铁中铁元素的摩尔比改为0.5:0.4。除此之外，其它参数和步骤均不变。
实施例14
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.37Mg0.04PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.37:0.04。除此之外，其它参数和步骤均不变。
实施例15
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.37Mg0.07PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，磷酸铁中铁元素及氧化镁中镁元素的摩尔比改为0.37:0.07。除此之外，其它参数和步骤均不变。
实施例16
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰 铁锂材料Li0.95Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(3)中，碳酸锂中锂元素和磷酸铁中铁元素的质量比为0.95:0.35。除此之外，其它参数和步骤均不变。
实施例17
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.1Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(3)中，碳酸锂中锂元素和磷酸铁中铁元素的质量比为1.1:0.35。除此之外，其它参数和步骤均不变。
实施例18
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Co0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，氧化镁改为氧化钴。除此之外，其它参数和步骤均不变。
实施例19
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Ca0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，氧化镁改为氧化钙。除此之外，其它参数和步骤均不变。
实施例20
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Sc0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，氧化镁改为氧化钪。除此之外，其它参数和步骤均不变。
实施例21
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Cr0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，氧化镁改为氧化铬。除此之外，其它参数和步骤均不变。
实施例22
本实施例与实施例1基本相同，区别仅在于，本实施例提供了一种磷酸锰 铁锂材料Li1.04Mn0.55Fe0.35V0.1PO4@C，正极材料中，碳含量为1.4％，本实施例步骤(1)中，氧化镁改为氧化钒。除此之外，其它参数和步骤均不变。
实施例23
本实施例与实施例1基本相同，区别仅在于，本实施例提供了第二前驱体Mn0.55Fe0.35Mg0.1PO4@C，第二前驱体中，碳含量为1％，以及第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C，第三前驱体中，碳含量为3％，相应的，可以制备出磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％。
本实施例制备方法中步骤(2)和(3)改为：
(2)在氮气保护下，将第一前驱体和PEG在550～750℃下焙烧，得到第二前驱体Mn0.55Fe0.35Mg0.1PO4@C。其中，PEG中碳元素的质量占第一前驱体和PEG总质量的4％。
(3)将第二前驱体、蔗糖、PEG、ATMP和碳酸锂进行混合研磨得到第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C；其中，蔗糖的添加质量占第二前驱体、蔗糖、PEG、ATMP总质量的8％，PEG的添加质量占第二前驱体、蔗糖、PEG、ATMP总质量的2％，碳酸锂中锂元素和磷酸铁中铁元素的质量比为1.04:0.35，ATMP的添加质量为磷酸铁的质量的3wt％。
实施例24
本实施例与实施例1基本相同，区别仅在于，本实施例提供了第二前驱体Mn0.55Fe0.35Mg0.1PO4@C，第二前驱体中，碳含量为5％，以及第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C，第三前驱体中，碳含量为3％，相应的，可以制备出磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为2％。
本实施例制备方法中步骤(2)和(3)改为：
(2)在氮气保护下，将第一前驱体和PEG在550～750℃下焙烧，得到第二前驱体Mn0.55Fe0.35Mg0.1PO4@C。其中，PEG中碳元素的质量占第一前驱体和PEG总质量的5％。
(3)将第二前驱体、ATMP和碳酸锂进行混合研磨得到第三前驱体 Li1.04Mn0.55Fe0.35Mg0.1PO4@C；其中，碳酸锂中锂元素和磷酸铁中铁元素的质量比为1.04:0.35，ATMP的添加质量为磷酸铁的质量的3wt％。
实施例25
本实施例与实施例1基本相同，区别仅在于，本实施例提供了第二前驱体Mn0.55Fe0.35Mg0.1PO4@C，第二前驱体中，碳含量为5.5％，以及第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C，第三前驱体中，碳含量为6％，相应的，可以制备出磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为3％。
本实施例制备方法中步骤(2)和(3)改为：
(2)在氮气保护下，将第一前驱体和PEG在550～750℃下焙烧，得到第二前驱体Mn0.55Fe0.35Mg0.1PO4@C。其中，PEG中碳元素的质量占第一前驱体和PEG总质量的17％。
(3)将第二前驱体、蔗糖、PEG、ATMP和碳酸锂进行混合研磨得到第三前驱体Li1.04Mn0.55Fe0.35Mg0.1PO4@C；其中，蔗糖中碳元素的质量占第二前驱体、蔗糖、PEG、ATMP总质量的3％，PEG中碳元素的质量占第二前驱体、蔗糖、PEG、ATMP总质量的1％，碳酸锂中锂元素和磷酸铁中铁元素的质量比为1.04:0.35，ATMP的添加质量为磷酸铁的质量的3wt％。
对比例1
本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.1PO4@C，正极材料中，碳含量为1.4％。
本对比例磷酸锰铁锂材料采用如下制备方法制备得到：
将碳酸锂、碳酸锰、磷酸铁、氧化镁、磷酸、以及石墨混合研磨，然后在氮气保护下进行焙烧，并在惰性气氛下冷却至室温，得到正极材料。
其中，碳酸锂中的锂元素、碳酸锰中的锰元素、磷酸铁中的铁元素、氧化镁中的镁元素、以及磷酸中的磷元素的摩尔比为1.04:0.55:0.35:0.1:1，石墨的质量占碳酸锂、碳酸锰、磷酸铁、氧化镁、磷酸以及石墨总质量的百分比为3.0％。
对比例2
本对比例与对比例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Co0.1PO4@C，正极材料中，碳含量为1.4％，本对比例中，氧化镁改为氧化钴。除此之外，其它参数和步骤均不变。
对比例3
本对比例与对比例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Ca0.1PO4@C，正极材料中，碳含量为1.4％，本对比例中，氧化镁改为氧化钙。除此之外，其它参数和步骤均不变。
对比例4
本对比例与对比例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Sc0.1PO4@C，正极材料中，碳含量为1.4％，本对比例中，氧化镁改为氧化钪。除此之外，其它参数和步骤均不变。
对比例5
本对比例与对比例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Cr0.1PO4@C，正极材料中，碳含量为1.4％，本对比例中，氧化镁改为氧化铬。除此之外，其它参数和步骤均不变。
对比例6
本对比例与对比例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35V0.1PO4@C，正极材料中，碳含量为1.4％，本对比例中，氧化镁改为氧化钒。除此之外，其它参数和步骤均不变。
对比例7
本对比例与实施例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.35Mg0.11PO4@C，正极材料中，碳含量为1.4％。
本对比例制备方法中，二氧化锰中锰元素、废铁中铁元素、氧化镁中镁元素以及磷酸中磷元素的摩尔比改为0.55:0.35:0.11:1。
对比例8
本对比例与实施例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.55Fe0.45PO4@C，正极材料中，碳含量为1.4％。
本对比例制备方法步骤(1)中，不添加氧化镁。
对比例9
本对比例与实施例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.96Fe0.1Mg0.01PO4@C，正极材料中，碳含量为1.4％。
本对比例制备方法步骤(1)中，二氧化锰中锰元素、废铁中铁元素、氧化镁中镁元素以及磷酸中磷元素的摩尔比改为0.96:0.1:0.01:1。
对比例10
本对比例与实施例1基本相同，区别仅在于，本对比例提供了一种磷酸锰铁锂材料Li1.04Mn0.1Fe0.96Mg0.01PO4@C，正极材料中，碳含量为1.4％。
本对比例制备方法步骤(1)中，二氧化锰中锰元素、废铁中铁元素、氧化镁中镁元素以及磷酸中磷元素的摩尔比改为0.1:0.96:0.01:1。
实验例
取上述实施例和对比例中制得的磷酸锰铁锂材料制备成电池并进行性能测试。
实施例和对比例的锂离子电池的制备方法如下：
(1)负极极片制备：将负极活性物质石墨、导电剂乙炔黑、粘结剂丁苯橡胶和增稠剂羧甲基纤维素钠按照重量比为石墨：乙炔黑：丁苯橡胶：羧甲基纤维素钠＝95:2:2:1进行混合，加入适量去离子水充分搅拌混合，形成均匀的负极浆料；将浆料涂覆于负极集流体铜箔上后，进行烘干、冷压，得到负极极片。
(2)正极极片制备：将相应的正极活性材料(即实施例和对比例中制得的磷酸锰铁锂材料)、导电剂乙炔黑和粘结剂聚偏二氟乙烯按重量比96:2:2进行混合，使用N-甲基吡咯烷酮作溶剂，充分研磨搅拌混合后，形成均匀的正极浆料；将浆料涂覆于正极集流体铝箔上后，进行烘干、冷压，得到正极极片。
(3)电池的制备：将正极片、隔离膜(PE/PP多孔聚合物薄膜)、负极片按顺序叠好，使隔离膜处于正负极片之间起到隔离的作用，然后卷绕得到裸电芯；将裸电芯置于外包装箔中，将EC(碳酸乙烯酯)/EMC(碳酸甲基乙基酯)等有机溶剂和LiPF6组成的锂离子电解液注入到干燥后的电池中，然后经过真空封装、静置、化成、整形等工序，获得锂离子电池。
性能测试方法：
使用恒温箱电池测试柜，在25℃的恒温环境中，1C-1C充放电条件下进行电池循环充放电测试，测试上述实施例及对比例磷酸锰铁锂材料所制备得到的电池的1C充电比能量以及1C放电比能量；
在25℃的恒温环境中，1C-1C充放电条件下进行电池循环充放电寿命测试，测试上述电池容量下降至额定容量的80％时，电池可达到的循环次数，记为25℃1C-1C循环次数@80％；在45℃的恒温环境中，1C-1C充放电条件下进行电池循环充放电寿命测试，测试上述电池容量下降至额定容量的80％时，电池可达到的循环次数，记为45℃1C-1C循环次数@80％。
结果记入表1。
表1


从上表可以看出：
实施例1具有优于对比例1的充放比能量以及循环次数，实施例18具有优于对比例2的充放比能量以及循环次数，实施例19具有优于对比例3的充放比能量以及循环次数，实施例20具有优于对比例4的充放比能量以及循环次数，实施例21具有优于对比例5的充放比能量以及循环次数，实施例22具有优于对比例6的充放比能量以及循环次数，说明相较常规的纯固相法，本申请采用液相-固相法合成材料并通过分级制备不同阶段的前驱体，且精确调控各前驱体结构，可以显著提高正极材料的比能量和循环次数；
相较对比例8，实施例1具有明显更高的充放比能量以及循环次数，说明本申请在正极材料中掺入掺杂金属元素，有助于提升正极材料的循环性能和比能量；
将对比例7和实施例1进行对比、对比例9和实施例5进行对比，对比例10和实施例6进行对比，各实施例具有明显更高的充放比能量以及循环次数，说明前驱体中各元素之间存在特定的摩尔比范围，当各元素的摩尔比在此范围内时，制得的正极材料具有良好的循环性能和比能量，进一步优化元素的摩尔比，使其落在优选范围内，有助于进一步提高正极材料的循环性能和比能量；当其中某一个元素的摩尔比超出范围，会导致材料的循环性能或比能量下降；
实施例23至实施例25中，实施例23和24的电池具有更高的充放比能量以及循环次数，说明调控前驱体中的碳含量有助于更好的调控正极材料的性能，当前驱体碳含量超出控制范围(碳含量小于等于5％)时，会导致材料的循环性能或比能量下降。

Claims (20)

  1. 一种前驱体的制备方法，包括以下步骤：
    提供多个第一原料组分，所述多个第一原料组分包括铁源、锰源、磷源、M源以及双氧水，将所述多个第一原料组分混合，干燥，得到第一前驱体，所述第一前驱体的通式为MnxFeyMzPO4·nH2O；
    其中，M为金属元素，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，n为0～10任意整数。
  2. 根据权利要求1所述的制备方法，其中，所述锰源中的锰元素、所述铁源中的铁元素、所述M源中的M元素以及所述磷源中的磷元素的摩尔比为(0.10～0.95)：(0.10～0.95)：(0.01～0.10)：1。
  3. 根据权利要求1所述的制备方法，其中，M元素包括镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种；和/或，
    所述铁源包括铁粉、无机铁盐及有机铁盐中的一种或多种，所述无机铁盐包括硫酸亚铁、磷酸铁、磷酸氢铁、磷酸二氢铁中的一种或多种，所述有机铁盐包括乙酸铁、草酸亚铁、酒石酸亚铁、乳酸亚铁、甲酸亚铁中的一种或多种；和/或，
    所述锰源包括无机锰盐和有机锰盐中的一种或多种，所述无机锰盐包括硫酸锰、碳酸锰、硝酸锰、磷酸锰、磷酸氢锰中的一种或多种，所述有机锰盐包括醋酸锰、草酸锰中的一种或多种；和/或，
    所述M源包括有机M盐和无机M盐中的一种或多种，所述有机M盐包括M元素的甲酸盐、M元素的乙酸盐、M元素的羟乙酸盐、M元素的乳酸盐、M元素的酒石酸盐、M元素的草酸盐中的一种或多种，所述无机M盐包括M元素的磷酸盐、M元素的磷酸氢盐、M元素的磷酸二氢盐、M元素的碳酸盐、M元素的氧化物、M元素的氢氧化物、M元素的氟化物、M元素的氯化物、 M元素的硝酸盐、M元素的硫酸盐、M元素的溴化物中的至少一种；和/或，
    所述磷源包括磷酸、磷酸二氢铵中的一种或两种。
  4. 根据权利要求1所述的制备方法，其中，所述制备方法还包括：提供焙烧料，所述焙烧料包括所述第一前驱体，将所述焙烧料进行焙烧，得到第二前驱体，所述第二前驱体包括通式为MnxFeyMzPO4的核。
  5. 根据权利要求4所述的制备方法，其中，所述第二前驱体还包括附着在所述核表面的碳层，所述碳层的质量占所述第二前驱体的质量的百分比小于等于5％。
  6. 根据权利要求5所述的制备方法，其中，所述焙烧料还包括第一碳源，所述第一碳源包括有机金属盐、有机碳源以及无机碳源中的一种或多种，所述有机金属盐包括有机铁盐、有机锰盐、有机M源中的一种或多种，所述有机碳源包括葡萄糖、蔗糖、乳糖、淀粉、有机酸、维生素、聚乙烯吡咯烷酮、聚乙二醇、羟乙基二膦酸、氨基三甲膦酸、二乙酸四胺以及酚醛树脂中的一种或多种，所述无机碳源包括石墨烯、碳纳米管以及石墨中的一种或多种。
  7. 根据权利要求5所述的制备方法，其中，所述焙烧料还包括第一碳源，且所述焙烧料中碳元素的质量占所述焙烧料的总质量的百分比为0～25％。
  8. 根据权利要求4至7任一项所述的制备方法，其中，所述制备方法还包括：提供多个第二原料组分，所述多个第二原料组分包括所述第二前驱体、锂源和表面活性剂，将所述多个第二原料组分混合，干燥，得到第三前驱体，所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料，其中，a为0.95～1.10。
  9. 根据权利要求8所述的制备方法，其中，所述锂源中的锂元素和所述铁源中的铁元素的摩尔比为(0.95～1.10)：(0.10～0.95)。
  10. 根据权利要求8所述的制备方法，其中，所述第三前驱体中，所述碳包覆层的质量占所述第三前驱体的质量的百分比为1％～5％。
  11. 根据权利要求8所述的制备方法，其中，所述多个第二原料组分还包 括第二碳源，且所述多个第二原料组分中碳元素的质量占所述多个第二原料组分的总质量的百分比为1～25％。
  12. 根据权利要求8所述的制备方法，其中，所述多个第二原料组分还包括第二碳源，所述第二碳源包括有机金属盐、有机碳源以及无机碳源中的一种或多种，所述有机金属盐包括有机铁盐、有机锰盐、有机M源、有机锂源中的一种或多种，所述有机碳源包括葡萄糖、蔗糖、乳糖、淀粉、有机酸、维生素、聚乙烯吡咯烷酮、聚乙二醇、羟乙基二膦酸、氨基三甲膦酸、二乙酸四胺以及酚醛树脂中的一种或多种，所述无机碳源包括石墨烯、碳纳米管以及石墨中的一种或多种；和/或，
    所述锂源包括锂的氧化物、氢氧化锂、有机锂盐以及无机锂盐中的一种或多种，所述锂的氧化物包括Li2O，所述无机锂盐包括碳酸锂、硫酸锂、硝酸锂、磷酸二氢锂、磷酸锂中的一种或多种，所述有机锂盐包括乙酸锂、草酸锂中的一种或多种。
  13. 一种前驱体，所述前驱体包括第一前驱体、第二前驱体和第三前驱体中的任意一种：
    所述第一前驱体的通式为MnxFeyMzPO4·nH2O；
    所述第二前驱体包括通式为MnxFeyMzPO4的核；
    所述第三前驱体包括内核以及包覆在所述内核的外表面上的碳包覆层，所述内核的材料包括通式为LiaMnxFeyMzPO4的材料；
    其中，M为金属元素，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，a为0.95～1.10，n为0～10任意整数。
  14. 根据权利要求13所述的前驱体，其中，M包括镁、钙、锶、钴、钛、锆、钼、钒、铌、镍、钪、铬、铜、锌、铍、镧以及铝中的一种或多种元素。
  15. 根据权利要求13所述的前驱体，其中，所述第二前驱体还包括附着在所述核表面的碳层，所述碳层的质量占所述第二前驱体的质量的百分比小于等于5％。
  16. 根据权利要求13所述的前驱体，其中，所述第三前驱体中，所述碳包覆层的质量占所述第三前驱体的质量的百分比为1％～5％；和/或，
    x为0.40～0.70；和/或，
    y为0.30～0.60；和/或，
    z为0.05～0.10；和/或，
    x、y及z的和为0.96～0.99。
  17. 一种正极材料，所述正极材料由前驱体制备得到，所述前驱体包括权利要求1至12任一项所述的制备方法制得的前驱体，或者，权利要求13至16任一项所述的前驱体。
  18. 根据权利要求17所述的正极材料，其中，所述正极材料包括内核以及包覆在内核外表面的碳包覆层，所述内核具有如下通式：LiaMnxFeyMzPO4；
    其中，M为金属元素，a为0.95～1.10，x为0.10～0.95，y为0.10～0.95，z为0.01～0.10，x、y及z的和为0.95～1.06，且所述正极材料中，所述碳包覆层的质量百分含量为1％～2％。
  19. 一种正极极片，包括正极集流体以及设置在所述正极集流体一侧的涂层，所述涂层的材料包括权利要求17或18所述的正极材料。
  20. 一种锂离子电池，包括权利要求19所述的正极极片。
PCT/CN2023/137863 2023-11-15 2023-12-11 前驱体及其制备方法、正极材料、正极极片及锂离子电池 Pending WO2025102463A1 (zh)

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