WO2023082182A1 - Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack, and electric device - Google Patents

Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack, and electric device Download PDF

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Publication number
WO2023082182A1
WO2023082182A1 PCT/CN2021/130350 CN2021130350W WO2023082182A1 WO 2023082182 A1 WO2023082182 A1 WO 2023082182A1 CN 2021130350 W CN2021130350 W CN 2021130350W WO 2023082182 A1 WO2023082182 A1 WO 2023082182A1
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Prior art keywords
positive electrode
active material
electrode active
optionally
phosphate
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PCT/CN2021/130350
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French (fr)
Chinese (zh)
Inventor
蒋耀
欧阳楚英
张欣欣
邓斌
赵旭山
王志强
袁天赐
刘少军
陈尚栋
徐波
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宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2021/130350 priority Critical patent/WO2023082182A1/en
Priority to CN202180093423.0A priority patent/CN116964774A/en
Priority to AU2022371736A priority patent/AU2022371736A1/en
Priority to KR1020237024611A priority patent/KR20230122108A/en
Priority to CN202280013384.3A priority patent/CN116964781A/en
Priority to PCT/CN2022/126829 priority patent/WO2023066393A1/en
Priority to PCT/CN2022/126838 priority patent/WO2023066394A1/en
Priority to CN202280007637.6A priority patent/CN116547835A/en
Priority to PCT/CN2022/126778 priority patent/WO2023066386A1/en
Priority to CN202280013385.8A priority patent/CN117121236A/en
Priority to KR1020247007998A priority patent/KR20240046889A/en
Priority to KR1020247008222A priority patent/KR20240048003A/en
Priority to EP22882990.9A priority patent/EP4261946A1/en
Priority to JP2023543271A priority patent/JP2024505446A/en
Publication of WO2023082182A1 publication Critical patent/WO2023082182A1/en
Priority to US18/351,925 priority patent/US20230361296A1/en

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    • 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
    • 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 lithium batteries, in particular to a positive electrode active material and a preparation method thereof, a positive electrode sheet containing the same, a secondary battery, a battery module, a battery pack and an electrical device.
  • lithium-ion batteries are widely used in various large-scale power devices, energy storage systems and various consumer products due to their excellent electrochemical performance, no memory effect, and low environmental pollution. Widely used in pure electric vehicles, hybrid electric vehicles and other new energy vehicles.
  • lithium manganese phosphate positive electrode active material has the advantages of high working voltage, wide range of raw material sources and less environmental pollution, and is considered to be the preferred positive electrode active material for lithium-ion batteries that is expected to replace lithium iron phosphate.
  • the cycle performance, high-temperature storage performance and safety performance of secondary batteries using lithium manganese phosphate cathode active materials have not been comprehensively improved, which greatly limits the wider application of lithium manganese phosphate batteries. Therefore, it is expected to design a lithium manganese phosphate secondary battery with high gram capacity, good cycle performance and safety performance.
  • the present application is made in view of the above problems, and its purpose is to provide a lithium manganese phosphate positive electrode active material, so that the secondary battery using the positive electrode active material has a higher gram capacity, good cycle performance and safety performance.
  • the present application provides a lithium manganese phosphate positive electrode active material and a preparation method thereof, as well as related positive electrode sheets, secondary batteries, battery modules, battery packs and electrical devices.
  • the first aspect of the present application provides a positive electrode active material with a core-shell structure, which includes an inner core and a shell covering the inner core,
  • the shell includes a first cladding layer covering the inner core and a second cladding layer covering the first cladding layer,
  • the first cladding layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein the M and X are each independently selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, One or more of Ag, Zr, Nb or Al;
  • the second cladding layer includes carbon.
  • the positive electrode active material of the present application can improve the gram capacity, cycle performance and safety performance of the secondary battery.
  • the lithium manganese phosphate positive electrode active material of the present application has a core-shell structure, wherein by doping the manganese site and phosphorus site of the lithium manganese phosphate core with element A and element R respectively, not only can effectively reduce The dissolution of manganese, thereby reducing the migration of manganese ions to the negative electrode, reducing the consumption of electrolyte due to the decomposition of the SEI film, improving the cycle performance and safety performance of the secondary battery, can also promote the adjustment of Mn-O bonds, and reduce the migration barrier of lithium ions.
  • the inner core by coating the inner core with the first coating layer including pyrophosphate and phosphate, the migration resistance of manganese can be further increased, its dissolution can be reduced, and the surface lithium impurities can be reduced. content, reduce the contact between the inner core and the electrolyte, thereby reducing the side reaction at the interface, reducing gas production, and improving the high-temperature storage performance, cycle performance and safety performance of the secondary battery; by further coating the carbon-containing layer as the second coating layer, The safety performance and dynamic performance of the secondary battery can be further improved.
  • the first coating layer including pyrophosphate and phosphate by coating the inner core with the first coating layer including pyrophosphate and phosphate, the migration resistance of manganese can be further increased, its dissolution can be reduced, and the surface lithium impurities can be reduced. content, reduce the contact between the inner core and the electrolyte, thereby reducing the side reaction at the interface, reducing gas production, and improving the high-temperature storage performance, cycle performance and safety performance of the secondary battery;
  • the interplanar spacing of the phosphate of the first cladding layer is 0.345-0.358nm, and the included angle of the crystal direction (111) is 24.25°-26.45°; the pyrophosphate of the first cladding layer The interplanar spacing is 0.293-0.326nm, and the included angle of the crystal direction (111) is 26.41°-32.57°.
  • the cycle performance and rate performance of the secondary battery are further improved.
  • the ratio of y to 1-y is 1:10 to 10:1, optionally 1:4 to 1:1.
  • the cycle performance and rate performance of the secondary battery are further improved.
  • the ratio of z to 1-z is 1:9 to 1:999, optionally 1:499 to 1:249.
  • the cycle performance and rate performance of the secondary battery are further improved.
  • the coating amount of the first coating layer is greater than 0% by weight and less than or equal to 7% by weight, optionally 4-5.6% by weight, based on the weight of the inner core.
  • the coating amount of the first coating layer is within the above range, the function of the first coating layer can be effectively exerted, and at the same time, the kinetic performance of the secondary battery will not be affected due to the over thickness of the coating layer.
  • the weight ratio of pyrophosphate to phosphate in the first coating layer is 1:3 to 3:1, optionally 1:3 to 1:1. Therefore, by using pyrophosphate and phosphate in a suitable weight ratio range, it can not only effectively hinder the dissolution of manganese, but also effectively reduce the content of lithium impurities on the surface and reduce the side reaction at the interface, thereby improving the high-temperature storage performance and safety performance of the secondary battery. and cycle performance.
  • the crystallinity of the pyrophosphate salt and the phosphate salt is independently 10%-100%, optionally 50%-100%. Therefore, the pyrophosphate and phosphate having the crystallinity in the above-mentioned range are conducive to fully exerting the functions of pyrophosphate to hinder manganese dissolution and phosphate to reduce the content of lithium impurities on the surface and reduce the side reaction at the interface.
  • the coating amount of the second coating layer is greater than 0% by weight and less than or equal to 6% by weight, optionally 3-5% by weight, based on the weight of the inner core. Therefore, the presence of the second coating layer can effectively reduce the contact between the active material in the coating layer and the electrolyte, reduce the corrosion of the active material by the electrolyte, and improve the conductivity of the positive electrode active material. When the coating amount of the second layer is within the above range, the gram capacity of the positive electrode active material can be effectively increased.
  • the A is selected from at least two of Fe, Ti, V, Ni, Co and Mg. Therefore, if A is two or more metals within the above range, doping at the manganese site is beneficial to enhance the doping effect, further reduce the surface oxygen activity, and thereby inhibit the dissolution of manganese.
  • the Li/Mn antisite defect concentration of the positive electrode active material is less than 4%, optionally less than 2%. Therefore, through the Li/Mn antisite defect concentration within the above range, Mn 2+ can be prevented from hindering the transport of Li + , and at the same time, the gram capacity and rate performance of the positive electrode active material can be improved.
  • the lattice change rate of the positive electrode active material is less than 6%, optionally less than 4%. Therefore, when the lattice change rate is within the above range, it is possible to avoid excessive interfacial stress from affecting Li + transport, thereby improving the rate performance of the secondary battery.
  • the surface oxygen valence state of the positive electrode active material is below -1.88, optionally between -1.98 and -1.88. Therefore, the surface oxygen valence state of the positive electrode material is within the above range, which can avoid the following situation that may be caused: because the surface oxygen valence state is too high, the ability to obtain electrons is too strong, resulting in increased interface side reactions with the electrolyte, thereby affecting the two.
  • the cycle performance and high temperature storage performance of the secondary battery is below -1.88, optionally between -1.98 and -1.88. Therefore, the surface oxygen valence state of the positive electrode material is within the above range, which can avoid the following situation that may be caused: because the surface oxygen valence state is too high, the ability to obtain electrons is too strong, resulting in increased interface side reactions with the electrolyte, thereby affecting the two.
  • the cycle performance and high temperature storage performance of the secondary battery is
  • the positive electrode active material has a compacted density at 3 tons (T) of 2.0 g/cm 3 or more, optionally 2.2 g/cm 3 or more. Therefore, if the compression density of the positive electrode active material is within the above range, the weight of the active material per unit volume is greater, which is more conducive to increasing the volumetric energy density of the secondary battery.
  • the second aspect of the present application provides a method for preparing a positive electrode active material, comprising the following steps:
  • the Said A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and may be One or more of Fe, Ti, V, Ni, Co and Mg
  • the R is selected from one or more of B, Si, N and S;
  • Coating step provide MP 2 O 7 powder and XPO 4 suspension containing carbon source, add the core material, MP 2 O 7 powder into XPO 4 suspension containing carbon source and mix, Sintering to obtain a positive electrode active material, wherein the M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al;
  • the positive electrode active material has a core-shell structure, which includes an inner core and a shell covering the inner core, and the shell includes a first cladding layer covering the inner core and a shell covering the first cladding layer.
  • the second coating layer, the first coating layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , and the second coating layer includes carbon.
  • the step of providing core material comprises the following steps:
  • Step (1) mixing and stirring a source of manganese, a source of element A, and an acid in a container to obtain manganese salt particles doped with element A;
  • the step (1) is carried out at a temperature of 20-120°C, optionally 25-80°C; and/or,
  • the stirring in the step (1) is carried out at 500-700 rpm for 60-420 minutes, optionally for 120-360 minutes.
  • the doping elements can be uniformly distributed, and the crystallinity of the material after sintering is higher, thereby improving the gram capacity and rate performance of the material.
  • the source of element A is selected from one or more of element A, sulfate, halide, nitrate, organic acid salt, oxide or hydroxide; and/or,
  • the source of the element R is selected from one or more of elemental R elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides, and inorganic acids of element R. Therefore, by selecting the source of each dopant element within the above range, the performance of the material can be effectively improved.
  • the MP 2 O 7 powder is prepared by adding the source of element M and the source of phosphorus into a solvent to obtain a mixture, adjusting the pH of the mixture to 4-6, stirring and fully reacting, and then Obtained by drying and sintering, wherein M is selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al.
  • the drying step is drying at 100-300°C, optionally 150-200°C, for 4-8h.
  • the sintering step is sintering at 500-800° C., optionally 650-800° C., for 4-10 hours in an inert gas atmosphere.
  • the sintering temperature in the cladding step is 500-800° C., and the sintering time is 4-10 h. Therefore, by controlling the sintering temperature and time during cladding, the gram capacity and rate performance of the material can be further improved.
  • the preparation method described in this application has wide sources of raw materials, low cost and simple process, which is beneficial to realize industrialization.
  • the third aspect of the present application provides a positive electrode sheet, which includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer includes the positive electrode active material described in the first aspect of the present application or by The positive electrode active material prepared by the method described in the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
  • the content of the positive electrode active material in the positive electrode film layer is 90-99.5% by weight, based on the total weight of the positive electrode film layer.
  • the content of the positive electrode active material is within the above range, it is beneficial to give full play to the advantages of the positive electrode active material of the present application.
  • the fourth aspect of the application provides a secondary battery, which includes the positive electrode active material described in the first aspect of the application or the positive electrode active material prepared by the method described in the second aspect of the application or the positive electrode active material described in the third aspect of the application Positive pole piece.
  • a fifth aspect of the present application provides a battery module, which includes the secondary battery described in the fourth aspect of the present application.
  • a sixth aspect of the present application provides a battery pack, which includes the battery module described in the fifth aspect of the present application.
  • the seventh aspect of the present application provides an electric device, which includes at least one of the secondary battery described in the fourth aspect of the present application, the battery module described in the fifth aspect of the present application, or the battery pack described in the sixth aspect of the present application. A sort of.
  • the positive electrode sheet, secondary battery, battery module, battery pack and electrical device described in the present application include the lithium manganese phosphate positive electrode active material described in the present application, and thus have at least the same advantages as the lithium manganese phosphate positive electrode active material.
  • FIG. 1 is a schematic diagram of a positive electrode active material with a core-shell structure according to an embodiment of the present application.
  • Fig. 2 is a comparison chart of the XRD spectrum of Example 1-1 of the present application before the first coating layer and the second coating layer are not coated with the standard XRD spectrum of lithium manganese phosphate (00-033-0804).
  • FIG. 3 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 3 .
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 6 .
  • FIG. 8 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • ranges disclosed herein are defined in terms of lower and upper limits, and a given range is defined by selecting a lower limit and an upper limit that define the boundaries of the specified range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range "a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c) , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b) and so on.
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • the median particle diameter Dv 50 refers to the particle diameter corresponding to when the cumulative volume distribution percentage of the positive electrode active material reaches 50%.
  • the median diameter Dv 50 of the positive electrode active material can be measured by laser diffraction particle size analysis.
  • a laser particle size analyzer such as Malvern Master Size 3000 is used for measurement.
  • coating layer refers to a material layer coated on the inner core.
  • the material layer can completely or partially cover the inner core.
  • the use of “coating layer” is only for the convenience of description and is not intended to limit the present invention. invention.
  • thickness of the coating layer refers to the thickness of the material layer coated on the inner core in the radial direction of the inner core.
  • the term “source” refers to a compound that is the source of a certain element.
  • the types of the “source” include but are not limited to carbonates, sulfates, nitrates, elemental substances, halides, oxides and hydroxide etc.
  • the inventors of the present application have found in practical work that the manganese elution is relatively serious in the deep charge and discharge process of the lithium manganese phosphate positive electrode active material. Although there are attempts in the prior art to coat lithium manganese phosphate with lithium iron phosphate to reduce interfacial side reactions, this coating cannot prevent the migration of dissolved manganese into the electrolyte. The dissolved manganese is reduced to metal manganese after migrating to the negative electrode.
  • the metal manganese produced is equivalent to a "catalyst", which can catalyze the decomposition of the SEI film (solid electrolyte interphase, solid electrolyte interphase film) on the surface of the negative electrode, and part of the by-products produced are gases, which can easily cause the battery to expand and affect the safety of the secondary battery.
  • the other part is deposited on the surface of the negative electrode, hindering the passage of lithium ions into and out of the negative electrode, causing the impedance of the secondary battery to increase and affecting the kinetic performance of the battery.
  • the electrolyte and the active lithium inside the battery are continuously consumed, which has an irreversible impact on the capacity retention of the secondary battery.
  • the inventors found that for lithium manganese phosphate positive electrode active materials, the problems of severe manganese dissolution and high surface reactivity may be caused by the ginger-Taylor effect of Mn 3+ and the change of Li + channel size after delithiation. For this reason, the inventor obtained a positive electrode active material that can significantly reduce manganese dissolution and lattice change rate by modifying lithium manganese phosphate, and then has good cycle performance, high-temperature storage performance and safety performance.
  • a first aspect of the present application provides a positive electrode active material with a core-shell structure, which includes an inner core and a shell covering the inner core,
  • the shell includes a first cladding layer covering the inner core and a second cladding layer covering the first cladding layer,
  • the first cladding layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein the M and X are each independently selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, One or more of Ag, Zr, Nb or Al;
  • the second cladding layer includes carbon.
  • the above-mentioned limitation on the numerical range of y is not only a limitation on the stoichiometric number of each element as A, but also a limitation on each element as A.
  • Limitation of the sum of stoichiometric numbers For example, when A is two or more elements A1, A2...An, the stoichiometric numbers y1, y2...yn of A1, A2...An each need to fall within the numerical range defined by the application for y, and y1 The sum of , y2 ... yn also needs to fall within this value range.
  • the limitation of the numerical range of the stoichiometric number of R in this application also has the above meaning.
  • the lithium manganese phosphate positive electrode active material of the present application has a core-shell structure with two cladding layers, wherein the inner core includes Li 1+x Mn 1-y A y P 1-z R z O 4 .
  • the element A doped at the manganese position of lithium manganese phosphate in the inner core helps to reduce the lattice change rate of lithium manganese phosphate during lithium deintercalation, improves the structural stability of lithium manganese phosphate cathode material, and greatly reduces the dissolution of manganese And reduce the oxygen activity on the particle surface.
  • the element R doped at the phosphorus site helps to change the difficulty of the change of the Mn-O bond length, thereby reducing the migration barrier of lithium ions, promoting the migration of lithium ions, and improving the rate performance of the secondary battery.
  • the first coating layer of the positive electrode active material of the present application includes pyrophosphate and phosphate. Due to the high migration barrier (>1eV) of transition metals in pyrophosphate, the dissolution of transition metals can be effectively suppressed. Phosphate has an excellent ability to conduct lithium ions, and can reduce the content of lithium impurities on the surface.
  • the second cladding layer is a carbon-containing layer, it can effectively improve the electrical conductivity and desolvation ability of LiMnPO 4 .
  • the "barrier" effect of the second cladding layer can further hinder the migration of manganese ions into the electrolyte and reduce the corrosion of the active materials by the electrolyte.
  • this application can effectively suppress the dissolution of Mn in the process of lithium intercalation and deintercalation, and at the same time promote the migration of lithium ions, thereby improving the rate performance of the battery cell and increasing the secondary The cycle performance and high temperature performance of the battery.
  • the positive electrode active material of the present application is basically consistent with the positions of the main characteristic peaks before doping of LiMnPO, indicating that doping
  • the mixed lithium manganese phosphate positive electrode active material has no impurity phase, and the improvement of the performance of the secondary battery is mainly caused by element doping, not the impurity phase.
  • the interplanar spacing of the phosphate of the first cladding layer is 0.345-0.358nm, and the included angle of the crystal direction (111) is 24.25°-26.45°; the first cladding layer The interplanar distance of pyrophosphate is 0.293-0.326nm, and the included angle of crystal direction (111) is 26.41°-32.57°.
  • the impurity phase in the cladding layer can be effectively avoided, thereby increasing the gram capacity of the material, and cycle performance and rate performance.
  • the ratio of y to 1-y is 1:10 to 10:1, optionally 1:4 to 1:1.
  • y represents the sum of stoichiometric numbers of Mn-site doping elements.
  • the ratio of z to 1-z is 1:9 to 1:999, optionally 1:499 to 1:249.
  • y represents the sum of the stoichiometric numbers of the P-site doping elements.
  • the coating amount of the first coating layer is greater than 0% by weight and less than or equal to 7% by weight, optionally 4-5.6% by weight, based on the weight of the inner core.
  • the coating amount of the first coating layer is within the above range, the dissolution of manganese can be further suppressed, and at the same time, the transport of lithium ions can be further promoted. And it can effectively avoid the following situation: if the coating amount of the first coating layer is too small, it may cause insufficient inhibition of pyrophosphate on manganese dissolution, and the improvement of lithium ion transport performance is not significant; If the coating amount of the first coating layer is too large, the coating layer may be too thick, which increases the battery impedance and affects the kinetic performance of the battery.
  • the weight ratio of pyrophosphate to phosphate in the first coating layer is 1:3 to 3:1, optionally 1:3 to 1:1.
  • the proper ratio of pyrophosphate and phosphate is conducive to giving full play to the synergistic effect of the two. And it can effectively avoid the following situations: if there is too much pyrophosphate and too little phosphate, it may lead to an increase in battery impedance; if there is too much phosphate and too little pyrophosphate, the effect of inhibiting the dissolution of manganese is not significant.
  • the crystallinity of the pyrophosphate salt and the phosphate salt is each independently 10% to 100%, optionally 50% to 100%.
  • pyrophosphate and phosphate with a certain degree of crystallinity are beneficial to keep the structure of the first coating layer stable and reduce lattice defects. On the one hand, this is beneficial to give full play to the role of pyrophosphate in hindering the dissolution of manganese. On the other hand, it is also beneficial to phosphate to reduce the content of lithium on the surface and the valence state of oxygen on the surface, thereby reducing the interface side reactions between the positive electrode material and the electrolyte, and reducing the The consumption of electrolyte improves the cycle performance and safety performance of the battery.
  • the crystallinity of pyrophosphate and phosphate can be adjusted, for example, by adjusting the process conditions of the sintering process, such as sintering temperature, sintering time, and the like.
  • the crystallinity of pyrophosphate and phosphate salts can be measured by methods known in the art, such as by X-ray diffraction, densitometry, infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance absorption methods.
  • the coating amount of the second coating layer is greater than 0% by weight and less than or equal to 6% by weight, optionally 3-5% by weight, based on the weight of the inner core.
  • the carbon-containing layer as the second coating layer can play a "barrier" function to avoid direct contact between the positive electrode active material and the electrolyte, thereby reducing the corrosion of the active material by the electrolyte and improving the safety performance of the battery at high temperatures.
  • it has strong electrical conductivity, which can reduce the internal resistance of the battery, thereby improving the kinetic performance of the battery.
  • the gram capacity of the carbon material is low, when the amount of the second coating layer is too large, the gram capacity of the entire positive electrode active material may be reduced. Therefore, when the coating amount of the second coating layer is in the above range, the kinetic performance and safety performance of the battery can be further improved without sacrificing the gram capacity of the positive electrode active material.
  • the A is selected from at least two of Fe, Ti, V, Ni, Co and Mg.
  • Simultaneously doping two or more of the above-mentioned elements on the manganese site in the lithium manganese phosphate positive electrode active material is beneficial to enhance the doping effect, on the one hand, further reduce the lattice change rate, thereby inhibiting the dissolution of manganese, and reducing the electrolyte and active lithium. On the other hand, it is also beneficial to further reduce the surface oxygen activity and reduce the interface side reaction between the positive electrode active material and the electrolyte, thereby improving the cycle performance and high temperature storage performance of the battery.
  • the Li/Mn antisite defect concentration of the positive electrode active material is less than 4%, optionally less than 2%.
  • the Li/Mn antisite defect means that in the LiMnPO 4 lattice, the positions of Li + and Mn 2+ are exchanged. Since the Li + transport channel is a one-dimensional channel, Mn 2+ is difficult to migrate in the Li + transport channel, so the Mn 2+ with antisite defects will hinder the transport of Li + .
  • the gram capacity and rate performance of LiMnPO4 can be improved by controlling the Li/Mn antisite defect concentration at a low level.
  • the antisite defect concentration can be measured according to JIS K 0131-1996, for example.
  • the lattice change rate of the positive electrode active material is less than 6%, optionally less than 4%.
  • the lithium-deintercalation process of LiMnPO 4 is a two-phase reaction.
  • the interfacial stress of the two phases is determined by the lattice change rate. The smaller the lattice change rate, the smaller the interfacial stress and the easier Li + transport. Therefore, reducing the lattice change rate of the inner core will be beneficial to enhance the Li + transport ability, thereby improving the rate performance of secondary batteries.
  • the average discharge voltage of the positive electrode active material is above 3.5V, and the discharge gram capacity is above 140mAh/g; optionally, the average discharge voltage is above 3.6V, and the discharge gram capacity is above 145mAh /g or more.
  • the average discharge voltage of undoped LiMnPO 4 is above 4.0V, its discharge gram capacity is low, usually less than 120mAh/g, so the energy density is low; adjusting the lattice change rate by doping can make it The discharge gram capacity has been greatly improved, and the overall energy density has increased significantly under the condition of a slight drop in the average discharge voltage.
  • the surface oxygen valence state of the positive electrode active material is below -1.88, optionally between -1.98 and -1.88.
  • the higher the valence state of oxygen in the compound the stronger its ability to obtain electrons, that is, the stronger the oxidation.
  • the reactivity of the surface of the positive electrode material can be reduced, and the interface side reaction between the positive electrode material and the electrolyte can be reduced, thereby improving the secondary The cycle performance and high temperature storage performance of the battery.
  • the positive electrode active material has a compacted density at 3 tons (T) of 2.0 g/cm 3 or more, optionally 2.2 g/cm 3 or more.
  • the compacted density can be measured according to GB/T 24533-2009, for example.
  • the second aspect of the present application provides the preparation method of the positive electrode active material of the first aspect of the present application, which comprises the following steps:
  • the Said A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and may be One or more of Fe, Ti, V, Ni, Co and Mg
  • the R is selected from one or more of B, Si, N and S;
  • Coating step provide MP 2 O 7 powder and XPO 4 suspension containing carbon source, add the core material, MP 2 O 7 powder into XPO 4 suspension containing carbon source and mix, Sintering to obtain a positive electrode active material, wherein the M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al;
  • the positive electrode active material has a core-shell structure, which includes an inner core and a shell covering the inner core, and the shell includes a first cladding layer covering the inner core and a shell covering the first cladding layer.
  • the second coating layer, the first coating layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , and the second coating layer includes carbon.
  • the preparation method of the present application has no special limitation on the source of the material.
  • the core material in the preparation method of the present application may be commercially available, or prepared by the method of the present application.
  • the core material is prepared by the method described below.
  • the step of providing the core material comprises the following steps:
  • Step (1) mixing and stirring a source of manganese, a source of element A, and an acid in a container to obtain manganese salt particles doped with element A;
  • the step (1) is carried out at a temperature of 20-120°C, optionally 25-80°C; and/or,
  • the stirring in the step (1) is carried out at 500-700 rpm for 60-420 minutes, optionally for 120-360 minutes.
  • the doping elements By controlling the reaction temperature, stirring rate and mixing time during doping, the doping elements can be evenly distributed, the lattice defects can be reduced, the dissolution of manganese can be suppressed, and the interface side reaction between the positive electrode active material and the electrolyte can be reduced, thereby improving the grammage of the material. capacity and rate performance, etc.
  • the source of a certain element may include one or more of elemental elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides of the element.
  • the body is the source that can realize the purpose of the preparation method of the present application.
  • the source of the element A is selected from one or more of element A, sulfate, halide, nitrate, organic acid salt, oxide or hydroxide; and/or, the element
  • the source of R is selected from one or more of elemental R elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides, and inorganic acids of element R.
  • the source of manganese in the present application is one or more selected from elemental manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate.
  • element A is iron
  • the source of iron is one or more selected from ferrous carbonate, ferric hydroxide, and ferrous sulfate.
  • the acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, organic acids such as oxalic acid, etc., and may be oxalic acid.
  • the acid is a dilute acid having a concentration of 60% by weight or less.
  • the mineral acid of element R is selected from one or more of phosphoric acid, nitric acid, boric acid, silicic acid, ortho silicic acid.
  • the source of lithium in the present application is one or more selected from lithium carbonate, lithium hydroxide, lithium phosphate, and lithium dihydrogen phosphate.
  • the source of phosphorus in the present application is one or more selected from diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate and phosphoric acid.
  • the source of carbon in the present application is an organic carbon source, and the organic carbon source is selected from one of starch, sucrose, glucose, polyvinyl alcohol, polyethylene glycol, and citric acid. one or more species.
  • the solvent used in the preparation method described in the present application is a solvent commonly used in the art.
  • the solvents in the preparation method of the present application can be independently selected from at least one of ethanol and water (eg, deionized water).
  • the pH of the solution is controlled to be 4-6. It should be noted that in this application, the pH of the resulting mixture can be adjusted by methods commonly used in the art, for example, by adding acid or base.
  • step (2) the molar ratio of the manganese salt particles to the source of lithium and the source of phosphorus is 1:0.5-2.1:0.5-2.1.
  • the sintering condition is: sintering at 600-800° C. for 4-10 hours in an atmosphere of inert gas or a mixture of inert gas and hydrogen.
  • the mixture of inert gas and hydrogen is nitrogen (70-90 volume %)+hydrogen (10-30 volume %).
  • the MP 2 O 7 powder is a commercially available product, or alternatively, the MP 2 O 7 powder is prepared by adding a source of element M and a source of phosphorus to In the solvent, the mixture is obtained, the pH of the mixture is adjusted to 4-6, stirred and fully reacted, then obtained by drying and sintering, wherein M is selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr , Nb or Al in one or more.
  • the drying step is drying at 100-300°C, optionally 150-200°C, for 4-8h.
  • the sintering step is sintering at 500-800° C., optionally 650-800° C., in an inert gas atmosphere for 4-10 hours.
  • the XPO suspension comprising a source of carbon is commercially available, or alternatively, is prepared by combining a source of lithium, a source of X, phosphorus The source of carbon and the source of carbon are uniformly mixed in a solvent, and then the reaction mixture is heated to 60-120° C. for 2-8 hours to obtain the XPO 4 suspension containing the source of carbon.
  • the pH of the mixture is adjusted to 4-6.
  • the mass ratio of the lithium manganese phosphate doped with the A element and the R element, MP 2 O 7 powder and XPO 4 suspension containing carbon source It is: 1:(0.001-0.05):(0.001-0.05).
  • the sintering temperature is 500-800° C., and the sintering time is 4-10 h.
  • the median particle diameter Dv50 of the primary particles of the double-layer coated lithium manganese phosphate positive electrode active material of the present application is 50-2000 nm.
  • the third aspect of the present application provides a positive electrode sheet, which includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the lithium manganese phosphate positive electrode active material according to the first aspect of the present application Or the lithium manganese phosphate positive electrode active material prepared according to the method of the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
  • the content of the positive electrode active material in the positive electrode film layer is 90-99.5% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid Formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET ethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode film layer may further optionally include a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer may also optionally include a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode film layer of the present application includes 90-99.5% of the lithium manganese phosphate positive electrode active material of the first aspect of the present application, 0.4-5.5% of the binder, 0.1-2.5% of the conductive carbon and 0.001- 1% of other additives, based on the total weight of the positive film layer.
  • the positive electrode film layer of the present application may also include other additives such as dispersants, wetting agents, rheology modifiers and other additives commonly used in this field.
  • the positive electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the coating weight of the anode film layer of the present application is 0.28-0.45g/1540.25mm 2 , and the compacted density reaches 2.2-2.8g/cm 3 .
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector can use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • CMC-Na sodium carboxymethylcellulose
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may optionally include additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • a separator is further included in the secondary battery.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • the fourth aspect of the application provides a secondary battery, which includes the positive electrode active material described in the first aspect of the application or the positive electrode active material prepared by the method described in the second aspect of the application or the positive electrode active material described in the third aspect of the application Positive pole piece.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
  • a lithium ion secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer package of the lithium-ion secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the lithium-ion secondary battery may also be a soft bag, such as a pouch-type soft bag.
  • the material of the soft bag may be plastic, and examples of plastic include polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).
  • FIG. 3 shows a square-shaped secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating cavity. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the lithium-ion secondary battery can be assembled into a battery module, and the number of lithium-ion batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 5 is a battery module 4 as an example.
  • a plurality of lithium-ion batteries 5 can be arranged sequentially along the length direction of the battery module 4 .
  • the plurality of lithium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may also include a housing with an accommodating space, and a plurality of lithium-ion batteries 5 are accommodated in the accommodating space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 8 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • the reactor was heated to 80° C. and stirred at 600 rpm for 6 hours until the reaction was terminated (no bubbles were generated), and a Fe, Co, V and S co-doped manganese oxalate suspension was obtained. Then the suspension was filtered, the filter cake was dried at 120° C., and then ground to obtain Fe, Co and V co-doped manganese oxalate dihydrate particles with a median diameter Dv50 of 100 nm.
  • the drying temperature was set at 250° C. and dried for 4 hours to obtain a powder.
  • a protective atmosphere of nitrogen (90 volume %) + hydrogen (10 volume %) the above powder was sintered at 700° C. for 4 hours to obtain 1572.1 g of Fe, Co, V and S co-doped lithium manganese phosphate.
  • lithium iron pyrophosphate powder 4.77 g of lithium carbonate, 7.47 g of ferrous carbonate, 14.84 g of ammonium dihydrogen phosphate and 1.3 g of oxalic acid dihydrate were dissolved in 50 ml of deionized water. The pH of the mixture was 5, and the reaction mixture was stirred for 2 hours to fully react. Then the temperature of the reacted solution was raised to 80°C and maintained at this temperature for 4 hours to obtain a suspension containing Li 2 FeP 2 O 7 , which was filtered, washed with deionized water, and dried at 120°C for 4 hours , to obtain powder. The powder was sintered at 650° C. under a nitrogen atmosphere for 8 hours, cooled naturally to room temperature, and then ground to obtain Li 2 FeP 2 O 7 powder.
  • lithium iron phosphate suspension dissolve 11.1g of lithium carbonate, 34.8g of ferrous carbonate, 34.5g of ammonium dihydrogen phosphate, 1.3g of oxalic acid dihydrate and 74.6g of sucrose (calculated as C 12 H 22 O 11 , the same below) The mixture was obtained in 150 ml of deionized water, and then stirred for 6 hours to fully react the above mixture. The reacted solution was then warmed up to 120 °C and kept at this temperature for 6 hours to obtain a suspension containing LiFePO4 .
  • the above-mentioned double-coated lithium manganese phosphate positive electrode active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) were added to N-methylpyrrolidone (NMP) in a weight ratio of 92:2.5:5.5 ), stir and mix evenly to obtain positive electrode slurry. Then, the positive electrode slurry was uniformly coated on the aluminum foil at a thickness of 0.280g/1540.25mm 2 , dried, cold pressed, and cut to obtain the positive electrode sheet.
  • NMP N-methylpyrrolidone
  • Negative electrode active material artificial graphite, hard carbon, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener carboxymethylcellulose sodium (CMC-Na) are 90: 5: 2: 2 according to weight ratio : 1 dissolved in deionized water as a solvent, stirred and mixed evenly to prepare negative electrode slurry.
  • the negative electrode slurry was evenly coated on the copper foil of the negative electrode current collector at a ratio of 0.117g/1540.25mm 2 , and the negative electrode sheet was obtained by drying, cold pressing, and slitting.
  • a commercially available PP-PE copolymer microporous film with a thickness of 20 ⁇ m and an average pore diameter of 80 nm was used.
  • the above obtained positive electrode sheet, separator, and negative electrode sheet are stacked in order, so that the separator is in the middle of the positive and negative electrodes to play the role of isolation, and the bare cell is obtained by winding. Place the bare cell in the outer package, inject the above electrolyte and package it to obtain a full battery (hereinafter also referred to as "full battery").
  • the above-mentioned double-coated lithium manganese phosphate positive electrode active material, PVDF, and acetylene black were added to NMP at a weight ratio of 90:5:5, and stirred in a drying room to form a slurry.
  • the above slurry is coated on the aluminum foil, dried and cold pressed to form a positive electrode sheet.
  • the coating amount was 0.2 g/cm 2
  • the compacted density was 2.0 g/cm 3 .
  • a lithium sheet is used as the negative electrode, and a solution of 1 mol/L LiPF 6 in ethylene carbonate (EC) + diethyl carbonate (DEC) + dimethyl carbonate (DMC) with a volume ratio of 1:1:1 is used as the electrolytic solution.
  • liquid and assembled into a button battery (hereinafter also referred to as "button battery") in a button box together with the above-mentioned positive pole piece prepared.
  • Examples 1-15 were the same as those of Examples 1-14.
  • Example 1-17 Except that in Example 1-16, 466.4g of NiCO 3 , 5.0g of zinc carbonate and 7.2g of titanium sulfate were used instead of ferrous carbonate during the preparation of the co-doped lithium manganese phosphate core, and in Example 1-17
  • the ferrous carbonate of 455.2g and the vanadium dichloride of 8.5g are used in the preparation process of the lithium manganese phosphate inner core, and the ferrous carbonate of 455.2g is used in the preparation process of the co-doped lithium manganese phosphate inner core in embodiment 1-18 , 4.9g of vanadium dichloride and 2.5g of magnesium carbonate, the conditions of Examples 1-17 to 1-19 are the same as in Example 1-7.
  • embodiment 1-19 uses the lithium carbonate of 369.4g in the preparation process of co-doped lithium manganese phosphate inner core, and replaces dilute sulfuric acid with the dilute nitric acid of 60% concentration of 1.05g
  • embodiment 1-20 is in co-doped
  • the conditions of Examples 1-19 to 1-20 are the same as those of Example 1-18, except that 369.7 g of lithium carbonate and 0.78 g of silicic acid are used instead of dilute sulfuric acid during the preparation of the lithium manganese phosphate inner core.
  • Examples 1-21 632.0g of manganese carbonate, 463.30g of ferrous carbonate, 30.5g of vanadium dichloride, 21.0g of magnesium carbonate and 0.78g of silicate were used in the preparation process of the co-doped lithium manganese phosphate core.
  • Embodiment 1-22 uses 746.9g manganese carbonate, 289.6g ferrous carbonate, 60.9g of vanadium dichloride, 42.1g of magnesium carbonate and 0.78g of silicate in the preparation process of co-doped lithium manganese phosphate core
  • the conditions of Examples 1-21 to 1-22 are the same as those of Example 1-20.
  • embodiment 1-23 uses 804.6g manganese carbonate, 231.7g ferrous carbonate, 1156.2g ammonium dihydrogen phosphate, 1.2g boric acid (mass fraction 99.5%) and 370.8 g lithium carbonate; embodiment 1-24 uses 862.1g manganese carbonate, 173.8g ferrous carbonate, 1155.1g ammonium dihydrogen phosphate, boric acid (mass fraction 99.5% of 1.86g) in the preparation process of co-doped lithium manganese phosphate core ) and 371.6g lithium carbonate, the conditions of embodiment 1-23 to 1-24 are identical with embodiment 1-22.
  • embodiment 1-25 uses 370.1g of lithium carbonate, 1.56g of silicic acid and 1147.7g of ammonium dihydrogen phosphate in the preparation process of the co-doped lithium manganese phosphate core, the conditions of embodiment 1-25 and embodiment 1-20 are the same.
  • embodiment 1-26 uses 368.3g lithium carbonate, 4.9g mass fraction to be 60% dilute sulfuric acid, 919.6g manganese carbonate, 224.8g ferrous carbonate, 3.7g dichloro Except the ammonium dihydrogen phosphate of vanadium, 2.5g magnesium carbonate and 1146.8g, the condition of embodiment 1-26 is identical with embodiment 1-20.
  • Example 1-27 uses 367.9g of lithium carbonate, 6.5g concentration of 60% dilute sulfuric acid and 1145.4g of ammonium dihydrogen phosphate in the preparation process of the co-doped lithium manganese phosphate core, the conditions of Example 1-27 Same as Example 1-20.
  • embodiment 1-28 to 1-33 uses 1034.5g manganese carbonate, 108.9g ferrous carbonate, 3.7g vanadium dichloride and 2.5g magnesium carbonate in the preparation process of co-doped lithium manganese phosphate inner core, the use of lithium carbonate
  • the amounts are: 367.6g, 367.2g, 366.8g, 366.4g, 366.0g, and 332.4g
  • the amounts of ammonium dihydrogen phosphate are: 1144.5g, 1143.4g, 1142.2g, 1141.1g, 1139.9g, and 1138.8g
  • Concentration is that the consumption of the dilute sulfuric acid of 60% is respectively: except 8.2g, 9.8g, 11.4g, 13.1g, 14.7g and 16.3g, the conditions of embodiment 1-28 to 1-33 are identical with embodiment 1-20 .
  • the sintering temperature in the powder sintering step is 550°C, and the sintering time is 1h to control the crystallinity of Li 2 FeP 2 O 7 to 30%.
  • the sintering temperature in the coating sintering step is 650° C., and the sintering time is 2 h to control the crystallinity of LiFePO 4 to 30%.
  • Other conditions are the same as in Example 1-1.
  • the sintering temperature in the powder sintering step is 550°C, and the sintering time is 2h to control the crystallinity of Li 2 FeP 2 O 7 to 50%.
  • the sintering temperature in the coating sintering step is 650° C., and the sintering time is 3 h to control the crystallinity of LiFePO 4 to 50%.
  • Other conditions are the same as in Example 1-1.
  • the sintering temperature in the powder sintering step is 600°C, and the sintering time is 3h to control the crystallinity of Li 2 FeP 2 O 7 to 70%.
  • the sintering temperature in the coating sintering step is 650° C., and the sintering time is 4 hours to control the crystallinity of LiFePO 4 to 70%.
  • Other conditions are the same as in Example 1-1.
  • the sintering temperature in the powder sintering step is 650°C, and the sintering time is 4h to control the crystallinity of Li 2 FeP 2 O 7 to 100%.
  • the sintering temperature in the coating sintering step was 700°C, and the sintering time was 6h to control the crystallinity of LiFePO 4 to 100%, other conditions were the same as in Example 1-1.
  • the heating temperature/stirring time in the reactor of Example 3-1 was respectively 60°C/120 minutes; the heating in the reactor of Example 3-2 Temperature/stirring time is respectively 70 °C/120 minutes; The heating temperature/stirring time in embodiment 3-3 reactor is respectively 80 °C/120 minutes; The heating temperature/stirring time in embodiment 3-4 reactor is respectively 90°C/120 minutes; the heating temperature/stirring time in the reactor of Example 3-5 was 100°C/120 minutes respectively; the heating temperature/stirring time in the reactor of Example 3-6 was 110°C/120 minutes respectively; The heating temperature/stirring time in the reactor of embodiment 3-7 is respectively 120 °C/120 minutes; The heating temperature/stirring time in the reactor of embodiment 3-8 is respectively 130 °C/120 minutes; Embodiment 3-9 reaction The heating temperature/stirring time in the kettle is respectively 100 DEG C/60 minutes; The heating temperature/stir
  • Examples 4-1 to 4-4 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the drying temperature/drying time in the drying step were 100°C/4h, 150°C/6h, 200°C/6h and 200°C/6h; the sintering temperature and sintering time in the sintering step during the preparation of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ) were 700°C/6h, 700°C/6h, 700°C, respectively Except for °C/6h and 600°C/6h, other conditions are the same as in Examples 1-7.
  • Examples 4-5 to 4-7 Except in the coating process, the drying temperature/drying time in the drying step is 150°C/6h, 150°C/6h and 150°C/6h respectively; Except that the sintering temperature and sintering time in the steps are 600°C/4h, 600°C/6h and 800°C/8h respectively, other conditions are the same as in Examples 1-12.
  • Preparation of carbon-coated lithium manganese phosphate take 1789.6g of manganese oxalate dihydrate particles obtained above, 369.4g of lithium carbonate (calculated as Li 2 CO 3 , the same below), 1150.1g of ammonium dihydrogen phosphate (calculated as NH 4 H 2 PO 4 meter, the same below) and 31 g of sucrose (calculated as C 12 H 22 O 11 , the same below) were added to 20 liters of deionized water, and the mixture was stirred for 10 hours to make it evenly mixed to obtain a slurry. The slurry was transferred to a spray drying device for spray drying and granulation. The drying temperature was set at 250° C. and dried for 4 hours to obtain a powder. In a nitrogen (90 volume %) + hydrogen (10 volume %) protective atmosphere, the above powder was sintered at 700° C. for 4 hours to obtain carbon-coated lithium manganese phosphate.
  • Comparative Example 2 Except for using 689.5g of manganese carbonate and additionally adding 463.3g of ferrous carbonate, other conditions of Comparative Example 2 were the same as those of Comparative Example 1.
  • the powder was sintered at 500°C under a nitrogen atmosphere for 4 hours, and ground after naturally cooling to room temperature.
  • the crystallinity of Li 2 FeP 2 O 7 was controlled to be 5%.
  • Li 2 FeP 2 Except that the consumption of O 7 is 62.8g, other conditions of Comparative Example 5 are the same as Comparative Example 4.
  • lithium iron phosphate suspension 14.7g lithium carbonate, 46.1g ferrous carbonate, 45.8g ammonium dihydrogen phosphate and 50.2g dihydrate oxalic acid were dissolved in 500ml deionized water, then stirred for 6 hours to make The mixture reacted well.
  • the reacted solution is heated to 120°C and maintained at this temperature for 6 hours to obtain a suspension containing LiFePO 4 , and the sintering temperature in the coating sintering step during the preparation of lithium iron phosphate (LiFePO 4 ) is 600°C ,
  • the sintering time is 4h to control the crystallinity of LiFePO 4 to be 8%, when preparing the carbon-coated material, the amount of LiFePO 4 is 62.8g, the other conditions of Comparative Example 6 are the same as Comparative Example 4.
  • lithium iron pyrophosphate powder 2.38 g of lithium carbonate, 7.5 g of ferrous carbonate, 7.4 g of ammonium dihydrogen phosphate and 8.1 g of oxalic acid dihydrate were dissolved in 50 ml of deionized water. The pH of the mixture was 5, and the reaction mixture was stirred for 2 hours to fully react. Then the temperature of the reacted solution was raised to 80°C and maintained at this temperature for 4 hours to obtain a suspension containing Li 2 FeP 2 O 7 , which was filtered, washed with deionized water, and dried at 120°C for 4 hours , to obtain powder. The powder was sintered at 500° C. under a nitrogen atmosphere for 4 hours, cooled naturally to room temperature, and then ground to control the crystallinity of Li 2 FeP 2 O 7 to 5%.
  • lithium iron phosphate suspension 11.1g of lithium carbonate, 34.7g of ferrous carbonate, 34.4g of ammonium dihydrogen phosphate, 37.7g of oxalic acid dihydrate and 37.3g of sucrose (calculated as C 12 H 22 O 11 , the same below) were dissolved in 1500 ml of deionized water, then stirred for 6 hours to fully react the mixture. The reacted solution was then warmed up to 120 °C and kept at this temperature for 6 hours to obtain a suspension containing LiFePO4 .
  • the sintering temperature in the coating sintering step is 600 ° C, and the sintering time is 4 hours to control the LiFePO 4 Except that the crystallinity of 4 was 8%, the other conditions of Comparative Example 7 were the same as those of Comparative Example 4, and amorphous lithium iron pyrophosphate, amorphous lithium iron phosphate, and carbon-coated positive electrode active materials were obtained.
  • the drying temperature/drying time in the drying step was 80°C/3h, 80°C/3h, 80°C/ 3h; the sintering temperature and sintering time in the sintering step during the preparation of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ) were 400°C/3h, 400°C/3h, and 350°C in Comparative Examples 8-10, respectively /2h, the drying temperature/drying time in the drying step during the preparation of lithium iron phosphate (LiFePO 4 ) in Comparative Example 11 was 80°C/3h; and Li 2 FeP 2 O 7 /LiFePO in Comparative Examples 8-11 Except that the dosage of 4 is 47.2g/15.7g, 15.7g/47.2g, 62.8g/0g, 0g/62.8g respectively, other conditions are the same as in Examples 1-7.
  • the button battery prepared above at a constant temperature of 25°C, let it stand for 5 minutes, discharge it at 0.1C to 2.5V, let it stand for 5 minutes, charge it at 0.1C to 4.3V, and then charge it at a constant voltage at 4.3V until the current is less than Equal to 0.05mA, let stand for 5 minutes; then discharge to 2.5V according to 0.1C, the discharge capacity at this time is the initial gram capacity, denoted as D0, the discharge energy is the initial energy, denoted as E0, and the average discharge voltage V after charging is E0 /D0.
  • the above-fabricated full cells were stored at 60°C at 100% state of charge (SOC).
  • SOC state of charge
  • the open circuit voltage (OCV) and AC internal resistance (IMP) of the cell are measured before, after and during storage to monitor the SOC, and the volume of the cell is measured.
  • the full battery was taken out after every 48 hours of storage, and the open circuit voltage (OCV) and internal resistance (IMP) were tested after standing for 1 hour, and the cell volume was measured by the drainage method after cooling to room temperature.
  • the batteries of all the examples kept the SOC above 99% during the experiment until the end of storage.
  • the anode active material sample was prepared as a button charge using the above button charge preparation method, and the above button charge was charged at a small rate of 0.05C until the current was reduced to 0.01C. Then take out the positive pole piece in the button battery, and soak in dimethyl carbonate (DMC) for 8 hours. Then dry, scrape the powder, and screen out the particles whose particle size is less than 500nm. Take a sample and calculate its unit cell volume v1 in the same way as the above-mentioned test fresh sample, and use (v0-v1)/v0 ⁇ 100% as the lattice change rate (unit cell volume change rate) before and after it completely deintercalates lithium. in the table.
  • DMC dimethyl carbonate
  • the Li/Mn antisite defect concentration is obtained. Specifically, import the XRD results tested in the "Measurement Method of Lattice Change Rate” into the General Structural Analysis System (GSAS) software, and automatically obtain the refined results, which include the occupancy of different atoms. By reading the refined As a result, the Li/Mn antisite defect concentration is obtained.
  • GSAS General Structural Analysis System
  • the full battery was discharged to a cut-off voltage of 2.0V at a rate of 0.1C after being cycled at 45°C until the capacity decayed to 80%. Then the battery was disassembled, and the negative pole piece was taken out. On the negative pole piece, 30 discs with a unit area (1540.25mm 2 ) were randomly selected, and the inductively coupled plasma emission spectrum (ICP) was tested with Agilent ICP-OES730. According to the ICP results, the amounts of Fe (if the Mn site of the positive electrode active material is doped with Fe) and Mn are calculated, so as to calculate the dissolution amount of Mn (and Fe doped at the Mn site) after cycling.
  • the test standard is based on EPA-6010D-2014.
  • the positive electrode active material sample prepared above Take 5 g of the positive electrode active material sample prepared above to prepare a button electrode according to the above button electrode preparation method. Charge the button with a small rate of 0.05C until the current decreases to 0.01C. Then take out the positive pole piece in the button battery, and soak in dimethyl carbonate (DMC) for 8 hours. Then dry, scrape the powder, and screen out the particles whose particle size is less than 500nm. The obtained particles were measured by electron energy loss spectroscopy (EELS, the instrument model used was Talos F200S), and the energy loss near-edge structure (ELNES) was obtained, which reflected the density of states and energy level distribution of the elements. According to the density of states and energy level distribution, the number of occupied electrons is calculated by integrating the data of the valence band density of states, so as to calculate the valence state of the charged surface oxygen.
  • DMC dimethyl carbonate
  • the positive electrode active material powder prepared above Take 5g of the positive electrode active material powder prepared above, and measure the total scattering intensity by X-rays, which is the sum of the scattering intensity of the entire space material, and is only related to the intensity of the primary ray, the chemical structure, and the total number of electrons participating in the diffraction, that is, the mass. It is related, but not related to the order state of the sample; then the crystalline scattering and the non-crystalline scattering are separated from the diffraction pattern, and the degree of crystallinity is the ratio of the crystalline partial scattering to the total scattering intensity.
  • the existence of the first cladding layer is beneficial to reduce the Li/Mn antisite defect concentration of the obtained material and the amount of Fe and Mn dissolved after cycling, and improve the battery performance. Reduce battery capacity and improve battery safety and cycle performance.
  • the lattice change rate, antisite defect concentration and Fe and Mn dissolution amount of the obtained material can be significantly reduced, the gram capacity of the battery can be increased, and the safety performance and cycle of the battery can be improved. performance.

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Abstract

Provided in the present application is a positive electrode active material with a core-shell structure, which material comprises an inner core and a shell coating the inner core, wherein the inner core comprises Li1+xMn1-yAyP1-zRzO4, in which x = -0.100 to 0.100, y = 0.001 to 0.500, z = 0.001 to 0.100, A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and is optionally one or more of Fe, Ti, V, Ni, Co and Mg, and R is selected from one or more of B, Si, N and S; and the shell comprises a first coating layer coating the inner core and a second coating layer coating the first coating layer, wherein the first coating layer comprises a pyrophosphate MP2O7 and a phosphate XPO4, in which M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al, and the second coating layer contains carbon.

Description

正极活性材料、正极极片、二次电池、电池模块、电池包和用电装置Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack and electrical device 技术领域technical field
本申请涉及锂电池技术领域，尤其涉及一种正极活性材料及其制备方法、包含其的正极极片、二次电池、电池模块、电池包和用电装置。The present application relates to the technical field of lithium batteries, in particular to a positive electrode active material and a preparation method thereof, a positive electrode sheet containing the same, a secondary battery, a battery module, a battery pack and an electrical device.
背景技术Background technique
随着新能源领域的快速发展，锂离子电池凭借其优良的电化学性能、无记忆效应、环境污染小等优势广泛应用于各类大型动力装置、储能系统以及各类消费类产品中，尤其广泛应用于纯电动汽车、混合电动汽车等新能源汽车领域。其中，磷酸锰锂正极活性材料具有工作电压高、原料来源广泛和对环境污染小等优点，被认为是有望取代磷酸铁锂而成为动力锂离子电池的首选正极活性材料。然而，在现有技术中，采用磷酸锰锂正极活性材料的二次电池的循环性能、高温存储性能和安全性能一直无法得到综合提升，这极大地限制了磷酸锰锂电池更大范围的应用。因此，期望设计出一款兼具较高的克容量、良好的循环性能和安全性能的磷酸锰锂二次电池。With the rapid development of the new energy field, lithium-ion batteries are widely used in various large-scale power devices, energy storage systems and various consumer products due to their excellent electrochemical performance, no memory effect, and low environmental pollution. Widely used in pure electric vehicles, hybrid electric vehicles and other new energy vehicles. Among them, lithium manganese phosphate positive electrode active material has the advantages of high working voltage, wide range of raw material sources and less environmental pollution, and is considered to be the preferred positive electrode active material for lithium-ion batteries that is expected to replace lithium iron phosphate. However, in the prior art, the cycle performance, high-temperature storage performance and safety performance of secondary batteries using lithium manganese phosphate cathode active materials have not been comprehensively improved, which greatly limits the wider application of lithium manganese phosphate batteries. Therefore, it is expected to design a lithium manganese phosphate secondary battery with high gram capacity, good cycle performance and safety performance.
发明内容Contents of the invention
本申请是鉴于上述课题而进行的，其目的在于，提供一种磷酸锰锂正极活性材料，使得应用所述正极活性材料的二次电池具有较高的克容量、良好的循环性能和安全性能。The present application is made in view of the above problems, and its purpose is to provide a lithium manganese phosphate positive electrode active material, so that the secondary battery using the positive electrode active material has a higher gram capacity, good cycle performance and safety performance.
为了达到上述目的，本申请提供了一种磷酸锰锂正极活性材料及其制备方法，以及相关的正极极片、二次电池、电池模块、电池包和用电装置。In order to achieve the above purpose, the present application provides a lithium manganese phosphate positive electrode active material and a preparation method thereof, as well as related positive electrode sheets, secondary batteries, battery modules, battery packs and electrical devices.
本申请的第一方面提供了一种具有核-壳结构的正极活性材料，其包括内核及包覆所述内核的壳，The first aspect of the present application provides a positive electrode active material with a core-shell structure, which includes an inner core and a shell covering the inner core,
所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100～0.100，y＝0.001～0.500，z＝0.001～0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； The inner core includes Li 1+x Mn 1-y A y P 1-z R z O 4 , wherein x=-0.100～0.100, y=0.001～0.500, z=0.001～0.100, and the A is selected from Zn, One or more of Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, may be Fe, Ti, V, One or more of Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，the shell includes a first cladding layer covering the inner core and a second cladding layer covering the first cladding layer,
其中，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Wherein, the first cladding layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein the M and X are each independently selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, One or more of Ag, Zr, Nb or Al;
所述第二包覆层包含碳。The second cladding layer includes carbon.
由此，本申请的正极活性材料能够提高二次电池的克容量、循环性能和安全性能。虽然机理尚不清楚，但推测是本申请的磷酸锰锂正极活性材料为核-壳结构，其中通过对磷酸锰锂内核的锰位和磷位分别掺杂元素A和元素R，不仅可有效减少锰溶出，进而减少迁移到负极的锰离子，减少因SEI膜分解而消耗的电解液，提高二次电池的循环性能和安全性能，还能够促进Mn-O键调整，降低锂离子迁移势垒，促进锂离子迁移，提高二次电池的倍率性能；通过对内核包覆包括焦磷酸盐和磷酸盐的第一包覆层，能够进一步增大锰的迁移阻力，减少其溶出，并减少表面杂锂含量、减少内核与电解液的接触，从而减少界面副反应、减少产气，提高二次电池的高温存储性能、循环性能和安全性能；通过进一步包覆作为第二包覆层的含碳层，能够进一步提升二次电池的安全性能和动力学性能。Thus, the positive electrode active material of the present application can improve the gram capacity, cycle performance and safety performance of the secondary battery. Although the mechanism is not yet clear, it is speculated that the lithium manganese phosphate positive electrode active material of the present application has a core-shell structure, wherein by doping the manganese site and phosphorus site of the lithium manganese phosphate core with element A and element R respectively, not only can effectively reduce The dissolution of manganese, thereby reducing the migration of manganese ions to the negative electrode, reducing the consumption of electrolyte due to the decomposition of the SEI film, improving the cycle performance and safety performance of the secondary battery, can also promote the adjustment of Mn-O bonds, and reduce the migration barrier of lithium ions. Promote the migration of lithium ions and improve the rate performance of the secondary battery; by coating the inner core with the first coating layer including pyrophosphate and phosphate, the migration resistance of manganese can be further increased, its dissolution can be reduced, and the surface lithium impurities can be reduced. content, reduce the contact between the inner core and the electrolyte, thereby reducing the side reaction at the interface, reducing gas production, and improving the high-temperature storage performance, cycle performance and safety performance of the secondary battery; by further coating the carbon-containing layer as the second coating layer, The safety performance and dynamic performance of the secondary battery can be further improved.
在任意实施方式中，所述第一包覆层的磷酸盐的晶面间距为0.345-0.358nm，晶向(111)的夹角为24.25°-26.45°；第一包覆层焦磷酸盐的晶面间距为0.293-0.326nm，晶向(111)的夹角为26.41°-32.57°。由此，进一步提升二次电池的循环性能和倍率性能。In any embodiment, the interplanar spacing of the phosphate of the first cladding layer is 0.345-0.358nm, and the included angle of the crystal direction (111) is 24.25°-26.45°; the pyrophosphate of the first cladding layer The interplanar spacing is 0.293-0.326nm, and the included angle of the crystal direction (111) is 26.41°-32.57°. Thus, the cycle performance and rate performance of the secondary battery are further improved.
在任意实施方式中，在所述内核中，y与1-y的比值为1∶10至 10∶1，可选为1∶4至1∶1。由此，进一步提升二次电池的循环性能和倍率性能。In any embodiment, in the kernel, the ratio of y to 1-y is 1:10 to 10:1, optionally 1:4 to 1:1. Thus, the cycle performance and rate performance of the secondary battery are further improved.
在任意实施方式中，在所述内核中，z与1-z的比值为1∶9至1∶999，可选为1∶499至1∶249。由此，进一步提升二次电池的循环性能和倍率性能。In any embodiment, in the kernel, the ratio of z to 1-z is 1:9 to 1:999, optionally 1:499 to 1:249. Thus, the cycle performance and rate performance of the secondary battery are further improved.
在任意实施方式中，所述第一包覆层的包覆量为大于0重量％且小于等于7重量％，可选为4-5.6重量％，基于所述内核的重量计。当第一包覆层的包覆量在上述范围内时，能够有效发挥第一包覆层的功能，同时不会由于包覆层过厚而影响二次电池的动力学性能。In any embodiment, the coating amount of the first coating layer is greater than 0% by weight and less than or equal to 7% by weight, optionally 4-5.6% by weight, based on the weight of the inner core. When the coating amount of the first coating layer is within the above range, the function of the first coating layer can be effectively exerted, and at the same time, the kinetic performance of the secondary battery will not be affected due to the over thickness of the coating layer.
在任意实施方式中，所述第一包覆层中焦磷酸盐和磷酸盐的重量比为1∶3至3∶1，可选为1∶3至1∶1。由此，通过焦磷酸盐和磷酸盐在合适的重量比范围，既可有效阻碍锰溶出，又可有效减少表面杂锂含量，减少界面副反应，从而提高二次电池的高温存储性能、安全性能和循环性能。In any embodiment, the weight ratio of pyrophosphate to phosphate in the first coating layer is 1:3 to 3:1, optionally 1:3 to 1:1. Therefore, by using pyrophosphate and phosphate in a suitable weight ratio range, it can not only effectively hinder the dissolution of manganese, but also effectively reduce the content of lithium impurities on the surface and reduce the side reaction at the interface, thereby improving the high-temperature storage performance and safety performance of the secondary battery. and cycle performance.
在任意实施方式中，所述焦磷酸盐和磷酸盐的结晶度各自独立地为10％-100％，可选为50％至100％。由此具备上述范围的结晶度的焦磷酸盐和磷酸盐有利于充分发挥焦磷酸盐阻碍锰溶出和磷酸盐减少表面杂锂含量、减少界面副反应的功能。In any embodiment, the crystallinity of the pyrophosphate salt and the phosphate salt is independently 10%-100%, optionally 50%-100%. Therefore, the pyrophosphate and phosphate having the crystallinity in the above-mentioned range are conducive to fully exerting the functions of pyrophosphate to hinder manganese dissolution and phosphate to reduce the content of lithium impurities on the surface and reduce the side reaction at the interface.
在任意实施方式中，所述第二包覆层的包覆量为大于0重量％且小于等于6重量％，可选为3-5重量％，基于所述内核的重量计。由此，第二包覆层的存在能够有效减少包覆层内活性材料与电解液的接触，减少电解液对活性材料的腐蚀，并提高正极活性材料的导电能力。当第二层包覆量在上述范围内时，能够有效提升正极活性材料的克容量。In any embodiment, the coating amount of the second coating layer is greater than 0% by weight and less than or equal to 6% by weight, optionally 3-5% by weight, based on the weight of the inner core. Therefore, the presence of the second coating layer can effectively reduce the contact between the active material in the coating layer and the electrolyte, reduce the corrosion of the active material by the electrolyte, and improve the conductivity of the positive electrode active material. When the coating amount of the second layer is within the above range, the gram capacity of the positive electrode active material can be effectively increased.
在任意实施方式中，所述A选自Fe、Ti、V、Ni、Co和Mg中的至少两种。由此，通过所述A为上述范围内的两种或更多种金属，因而在锰位掺杂有利于增强掺杂效果，进一步降低表面氧活性，从而抑制锰的溶出。In any embodiment, the A is selected from at least two of Fe, Ti, V, Ni, Co and Mg. Therefore, if A is two or more metals within the above range, doping at the manganese site is beneficial to enhance the doping effect, further reduce the surface oxygen activity, and thereby inhibit the dissolution of manganese.
在任意实施方式中，所述正极活性材料的Li/Mn反位缺陷浓度为4％以下，可选为2％以下。由此，通过Li/Mn反位缺陷浓度在上述范 围内，能够避免Mn 2+阻碍Li +的传输，同时提升正极活性材料的克容量和倍率性能。 In any embodiment, the Li/Mn antisite defect concentration of the positive electrode active material is less than 4%, optionally less than 2%. Therefore, through the Li/Mn antisite defect concentration within the above range, Mn 2+ can be prevented from hindering the transport of Li + , and at the same time, the gram capacity and rate performance of the positive electrode active material can be improved.
在任意实施方式中，所述正极活性材料的晶格变化率为6％以下，可选为4％以下。由此，通过晶格变化率在上述范围内，能够避免界面应力过大而影响Li +传输，从而提升二次电池的倍率性能。 In any embodiment, the lattice change rate of the positive electrode active material is less than 6%, optionally less than 4%. Therefore, when the lattice change rate is within the above range, it is possible to avoid excessive interfacial stress from affecting Li + transport, thereby improving the rate performance of the secondary battery.
在任意实施方式中，所述正极活性材料的表面氧价态为-1.88以下，可选地为-1.98～-1.88。由此，正极材料的表面氧价态在上述范围内，能够避免可能导致的以下情况：由于表面氧价态过高，得电子能力过强，导致增加与电解液的界面副反应，从而影响二次电池的循环性能和高温储存性能。In any embodiment, the surface oxygen valence state of the positive electrode active material is below -1.88, optionally between -1.98 and -1.88. Therefore, the surface oxygen valence state of the positive electrode material is within the above range, which can avoid the following situation that may be caused: because the surface oxygen valence state is too high, the ability to obtain electrons is too strong, resulting in increased interface side reactions with the electrolyte, thereby affecting the two. The cycle performance and high temperature storage performance of the secondary battery.
在任意实施方式中，所述正极活性材料在3吨(T)下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。由此，正极活性材料的压密度在上述范围内，则单位体积活性物质的重量更大，将更有利于提升二次电池的体积能量密度。 In any embodiment, the positive electrode active material has a compacted density at 3 tons (T) of 2.0 g/cm 3 or more, optionally 2.2 g/cm 3 or more. Therefore, if the compression density of the positive electrode active material is within the above range, the weight of the active material per unit volume is greater, which is more conducive to increasing the volumetric energy density of the secondary battery.
本申请第二方面提供一种正极活性材料的制备方法，包括以下步骤：The second aspect of the present application provides a method for preparing a positive electrode active material, comprising the following steps:
提供内核材料的步骤：所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； Step of providing core material: the core comprises Li 1+x Mn 1-y A y P 1-z R z O 4 , where x=-0.100-0.100, y=0.001-0.500, z=0.001-0.100, the Said A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and may be One or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
包覆步骤：提供MP 2O 7粉末和包含碳的源的XPO 4悬浊液，将所述内核材料、MP 2O 7粉末加入到包含碳的源的XPO 4悬浊液中并混合，经烧结获得正极活性材料，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Coating step: provide MP 2 O 7 powder and XPO 4 suspension containing carbon source, add the core material, MP 2 O 7 powder into XPO 4 suspension containing carbon source and mix, Sintering to obtain a positive electrode active material, wherein the M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al;
其中，所述正极活性材料具有核-壳结构，其包括内核及包覆所述内核的壳，所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，所述第二包覆层包含碳。 Wherein, the positive electrode active material has a core-shell structure, which includes an inner core and a shell covering the inner core, and the shell includes a first cladding layer covering the inner core and a shell covering the first cladding layer. The second coating layer, the first coating layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , and the second coating layer includes carbon.
在任意实施方式中，所述提供内核材料的步骤包括以下步骤：In any embodiment, the step of providing core material comprises the following steps:
步骤(1)：将锰的源、元素A的源和酸在容器中混合并搅拌，得到掺杂有元素A的锰盐颗粒；Step (1): mixing and stirring a source of manganese, a source of element A, and an acid in a container to obtain manganese salt particles doped with element A;
步骤(2)：将所述掺杂有元素A的锰盐颗粒与锂的源、磷的源和元素R的源在溶剂中混合并得到浆料，在惰性气体气氛保护下烧结后得到掺杂有元素A和元素R的磷酸锰锂，其中，所述掺杂有元素A和元素R的磷酸锰锂为Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种。 Step (2): Mix the manganese salt particles doped with element A with a source of lithium, a source of phosphorus and a source of element R in a solvent to obtain a slurry, which is sintered under the protection of an inert gas atmosphere to obtain a doped Lithium manganese phosphate with element A and element R, wherein the lithium manganese phosphate doped with element A and element R is Li 1+x Mn 1-y A y P 1-z R z O 4 , where x= -0.100-0.100, y=0.001-0.500, z=0.001-0.100, said A is selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, One or more of Sn, Sb, Nb and Ge, optionally one or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from B, Si, N and S one or more of .
在任意实施方式中，所述步骤(1)在20-120℃，可选为25-80℃的温度下进行；和/或，In any embodiment, the step (1) is carried out at a temperature of 20-120°C, optionally 25-80°C; and/or,
所述步骤(1)中所述搅拌在500-700rpm下进行60-420分钟，可选地为120-360分钟。The stirring in the step (1) is carried out at 500-700 rpm for 60-420 minutes, optionally for 120-360 minutes.
由此，通过控制掺杂时的反应温度、搅拌速率和混合时间，能够使掺杂元素均匀分布，并且烧结后材料的结晶度更高，从而可提升材料的克容量和倍率性能等。Therefore, by controlling the reaction temperature, stirring rate and mixing time during doping, the doping elements can be uniformly distributed, and the crystallinity of the material after sintering is higher, thereby improving the gram capacity and rate performance of the material.
在任意实施方式中，所述元素A的源选自元素A的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物中的一种或多种；和/或，所述元素R的源选自元素R的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物以及元素R的无机酸中的一种或多种。由此，通过在上述范围内选择各掺杂元素的源，能够有效改善材料的性能。In any embodiment, the source of element A is selected from one or more of element A, sulfate, halide, nitrate, organic acid salt, oxide or hydroxide; and/or, The source of the element R is selected from one or more of elemental R elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides, and inorganic acids of element R. Therefore, by selecting the source of each dopant element within the above range, the performance of the material can be effectively improved.
在任意实施方式中，所述MP 2O 7粉末通过以下方法制备：将元素M的源和磷的源添加到溶剂中，得到混合物，调节混合物的pH为4-6，搅拌并充分反应，然后经干燥、烧结获得，其中M选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种。 In any embodiment, the MP 2 O 7 powder is prepared by adding the source of element M and the source of phosphorus into a solvent to obtain a mixture, adjusting the pH of the mixture to 4-6, stirring and fully reacting, and then Obtained by drying and sintering, wherein M is selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al.
在任意实施方式中，在制备MP 2O 7粉末过程中，所述干燥步骤为在100-300℃、可选150-200℃下干燥4-8h。 In any embodiment, during the preparation of MP 2 O 7 powder, the drying step is drying at 100-300°C, optionally 150-200°C, for 4-8h.
在任意实施方式中，在制备MP 2O 7粉末过程中，所述烧结步骤 为在500-800℃、可选650-800℃下，在惰性气体气氛下烧结4-10h。 In any embodiment, during the preparation of MP 2 O 7 powder, the sintering step is sintering at 500-800° C., optionally 650-800° C., for 4-10 hours in an inert gas atmosphere.
在任意实施方式中，所述包覆步骤中烧结温度为500-800℃，烧结时间为4-10h。由此，通过控制包覆时的烧结温度和时间，可以进一步提升材料的克容量和倍率性能等。In any embodiment, the sintering temperature in the cladding step is 500-800° C., and the sintering time is 4-10 h. Therefore, by controlling the sintering temperature and time during cladding, the gram capacity and rate performance of the material can be further improved.
本申请所述制备方法，原料来源广泛、成本低廉，工艺简单，有利于实现工业化。The preparation method described in this application has wide sources of raw materials, low cost and simple process, which is beneficial to realize industrialization.
本申请第三方面提供一种正极极片，其包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请第一方面所述的正极活性材料或通过本申请第二方面所述的方法制备的正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。The third aspect of the present application provides a positive electrode sheet, which includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer includes the positive electrode active material described in the first aspect of the present application or by The positive electrode active material prepared by the method described in the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
在任意实施方式中，所述正极活性材料在所述正极膜层中的含量为90-99.5重量％，基于所述正极膜层的总重量计。当所述正极活性材料的含量在上述范围内时，有利于充分发挥本申请正极活性材料的优势。In any embodiment, the content of the positive electrode active material in the positive electrode film layer is 90-99.5% by weight, based on the total weight of the positive electrode film layer. When the content of the positive electrode active material is within the above range, it is beneficial to give full play to the advantages of the positive electrode active material of the present application.
本申请第四方面提供一种二次电池，其包括本申请第一方面所述的正极活性材料或通过本申请第二方面所述的方法制备的正极活性材料或本申请第三方面所述的正极极片。The fourth aspect of the application provides a secondary battery, which includes the positive electrode active material described in the first aspect of the application or the positive electrode active material prepared by the method described in the second aspect of the application or the positive electrode active material described in the third aspect of the application Positive pole piece.
本申请第五方面提供一种电池模块，其包括本申请第四方面所述的二次电池。A fifth aspect of the present application provides a battery module, which includes the secondary battery described in the fourth aspect of the present application.
本申请第六方面提供一种电池包，其包括本申请第五方面所述的电池模块。A sixth aspect of the present application provides a battery pack, which includes the battery module described in the fifth aspect of the present application.
本申请第七方面提供一种用电装置，其包括本申请第四方面所述的二次电池、本申请第五方面所述的电池模块或本申请第六方面所述的电池包中的至少一种。The seventh aspect of the present application provides an electric device, which includes at least one of the secondary battery described in the fourth aspect of the present application, the battery module described in the fifth aspect of the present application, or the battery pack described in the sixth aspect of the present application. A sort of.
本申请所述正极极片、二次电池、电池模块、电池包和用电装置包括本申请所述的磷酸锰锂正极活性材料，因而至少具有与所述磷酸锰锂正极活性材料相同的优势。The positive electrode sheet, secondary battery, battery module, battery pack and electrical device described in the present application include the lithium manganese phosphate positive electrode active material described in the present application, and thus have at least the same advantages as the lithium manganese phosphate positive electrode active material.
附图说明Description of drawings
图1为本申请一实施方式的具有核壳结构的正极活性材料的示意图。FIG. 1 is a schematic diagram of a positive electrode active material with a core-shell structure according to an embodiment of the present application.
图2为本申请实施例1-1在未包覆第一包覆层和第二包覆层之前的XRD谱图与磷酸锰锂XRD标准谱图(00-033-0804)的对比图。Fig. 2 is a comparison chart of the XRD spectrum of Example 1-1 of the present application before the first coating layer and the second coating layer are not coated with the standard XRD spectrum of lithium manganese phosphate (00-033-0804).
图3是本申请一实施方式的二次电池的示意图。FIG. 3 is a schematic diagram of a secondary battery according to an embodiment of the present application.
图4是图3所示的本申请一实施方式的二次电池的分解图。FIG. 4 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 3 .
图5是本申请一实施方式的电池模块的示意图。FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
图6是本申请一实施方式的电池包的示意图。FIG. 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
图7是图6所示的本申请一实施方式的电池包的分解图。FIG. 7 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 6 .
图8是本申请一实施方式的二次电池用作电源的用电装置的示意图。FIG. 8 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
附图标记说明：Explanation of reference signs:
11内核；12第一包覆层；13第二包覆层；11 inner core; 12 first cladding layer; 13 second cladding layer;
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly
具体实施方式Detailed ways
以下，适当地参照附图详细说明具体公开了本申请的正极活性材料及其制造方法、正极极片、二次电池、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。Hereinafter, embodiments of the positive electrode active material, the manufacturing method thereof, the positive electrode sheet, the secondary battery, the battery module, the battery pack, and the electrical device of the present application will be disclosed in detail with reference to the accompanying drawings. However, unnecessary detailed description may be omitted. For example, detailed descriptions of well-known items and repeated descriptions of substantially the same configurations may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特定范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110 的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。A "range" disclosed herein is defined in terms of lower and upper limits, and a given range is defined by selecting a lower limit and an upper limit that define the boundaries of the specified range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, 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 "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values. In addition, when expressing that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。If there is no special description, all the implementation modes and optional implementation modes of the present application can be combined with each other to form new technical solutions.
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。If there is no special description, all the technical features and optional technical features of the present application can be combined with each other to form a new technical solution.
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。Unless otherwise specified, all steps in the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence. For example, mentioning that the method may also include step (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c) , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b) and so on.
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。If there is no special description, the "comprising" and "comprising" mentioned in this application mean open or closed. For example, the "comprising" and "comprising" may mean that other components not listed may be included or included, or only listed components may be included or included.
本申请中使用的术语“以上”、“以下”包含本数，例如“一种以上”是指一种或多种，“A和B中的一种以上”是指“A”、“B”或“A和B”。The terms "above" and "below" used in this application include the number, for example, "more than one" refers to one or more, "more than one of A and B" refers to "A", "B" or "A and B".
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B 都为真(或存在)。In this application, the term "or" is inclusive unless otherwise stated. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
需要说明的是，在本文中，中值粒径Dv 50是指，所述正极活性材料累计体积分布百分数达到50％时所对应的粒径。在本申请中，正极活性材料的中值粒径Dv 50可采用激光衍射粒度分析法测定。例如参照标准GB/T 19077-2016，使用激光粒度分析仪(例如Malvern Master Size 3000)进行测定。 It should be noted that, herein, the median particle diameter Dv 50 refers to the particle diameter corresponding to when the cumulative volume distribution percentage of the positive electrode active material reaches 50%. In the present application, the median diameter Dv 50 of the positive electrode active material can be measured by laser diffraction particle size analysis. For example, with reference to the standard GB/T 19077-2016, a laser particle size analyzer (such as Malvern Master Size 3000) is used for measurement.
在本文中，术语“包覆层”是指包覆在内核上的物质层，所述物质层可以完全或部分地包覆内核，使用“包覆层”只是为了便于描述，并不意图限制本发明。同样地，术语“包覆层的厚度”是指包覆在内核上的所述物质层在内核径向上的厚度。In this article, the term "coating layer" refers to a material layer coated on the inner core. The material layer can completely or partially cover the inner core. The use of "coating layer" is only for the convenience of description and is not intended to limit the present invention. invention. Likewise, the term "thickness of the coating layer" refers to the thickness of the material layer coated on the inner core in the radial direction of the inner core.
在本文中，术语“源”是指作为某种元素的来源的化合物，作为实例，所述“源”的种类包括但不限于碳酸盐、硫酸盐、硝酸盐、单质、卤化物、氧化物和氢氧化物等。As used herein, the term "source" refers to a compound that is the source of a certain element. As an example, the types of the "source" include but are not limited to carbonates, sulfates, nitrates, elemental substances, halides, oxides and hydroxide etc.
本申请发明人在实际作业中发现：磷酸锰锂正极活性材料在深度充放电过程中，锰溶出比较严重。虽然现有技术中有尝试对磷酸锰锂进行磷酸铁锂包覆，从而减少界面副反应，但这种包覆无法阻止溶出的锰向电解液中的迁移。溶出的锰在迁移到负极后，被还原成金属锰。这些产生的金属锰相当于“催化剂”，能够催化负极表面的SEI膜(solid electrolyte interphase，固态电解质界面膜)分解，产生的副产物一部分为气体，容易导致电池发生膨胀，影响二次电池的安全性能，另一部分沉积在负极表面，阻碍锂离子进出负极的通道，造成二次电池的阻抗增加，影响电池的动力学性能。此外，为补充损失的SEI膜，电解液和电池内部的活性锂被不断消耗，给二次电池的容量保持率带来不可逆的影响。The inventors of the present application have found in practical work that the manganese elution is relatively serious in the deep charge and discharge process of the lithium manganese phosphate positive electrode active material. Although there are attempts in the prior art to coat lithium manganese phosphate with lithium iron phosphate to reduce interfacial side reactions, this coating cannot prevent the migration of dissolved manganese into the electrolyte. The dissolved manganese is reduced to metal manganese after migrating to the negative electrode. The metal manganese produced is equivalent to a "catalyst", which can catalyze the decomposition of the SEI film (solid electrolyte interphase, solid electrolyte interphase film) on the surface of the negative electrode, and part of the by-products produced are gases, which can easily cause the battery to expand and affect the safety of the secondary battery. The other part is deposited on the surface of the negative electrode, hindering the passage of lithium ions into and out of the negative electrode, causing the impedance of the secondary battery to increase and affecting the kinetic performance of the battery. In addition, in order to supplement the lost SEI film, the electrolyte and the active lithium inside the battery are continuously consumed, which has an irreversible impact on the capacity retention of the secondary battery.
发明人经过大量研究后发现，对于磷酸锰锂正极活性材料，锰溶出严重和表面反应活性高等问题可能是由于脱锂后Mn 3+的姜-泰勒效应和Li +通道大小变化引起的。为此，发明人通过对磷酸锰锂进行改性，得到了能够显著降低锰溶出和降低晶格变化率，进而具备良好的循环性能、高温存储性能和安全性能的正极活性材料。 After a lot of research, the inventors found that for lithium manganese phosphate positive electrode active materials, the problems of severe manganese dissolution and high surface reactivity may be caused by the ginger-Taylor effect of Mn 3+ and the change of Li + channel size after delithiation. For this reason, the inventor obtained a positive electrode active material that can significantly reduce manganese dissolution and lattice change rate by modifying lithium manganese phosphate, and then has good cycle performance, high-temperature storage performance and safety performance.
[正极活性材料][Positive electrode active material]
本申请的第一方面提供一种具有核-壳结构的正极活性材料，其包括内核及包覆所述内核的壳，A first aspect of the present application provides a positive electrode active material with a core-shell structure, which includes an inner core and a shell covering the inner core,
所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100～0.100，例如x可以为0.006、0.004、0.003、0.002、0.001、0、-0.001、-0.003、-0.004、-0.005、-0.006、-0.007、-0.008、-0.009、-0.10；y＝0.001～0.500，例如y可以为0.1、0.2、0.25、0.3、0.35、0.4、0.45；z＝0.001～0.100，例如z可以为0.001、0.002、0.003、0.004、0.005、0.006、0.007、0.008、0.009、0.1；所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； The inner core includes Li 1+x Mn 1-y A y P 1-z R z O 4 , where x=-0.100～0.100, for example, x can be 0.006, 0.004, 0.003, 0.002, 0.001, 0, -0.001, -0.003, -0.004, -0.005, -0.006, -0.007, -0.008, -0.009, -0.10; y=0.001～0.500, for example, y can be 0.1, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45; z= 0.001～0.100, for example z can be 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.1; said A is selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V , one or more of Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, may be one or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，the shell includes a first cladding layer covering the inner core and a second cladding layer covering the first cladding layer,
其中，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Wherein, the first cladding layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein the M and X are each independently selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, One or more of Ag, Zr, Nb or Al;
所述第二包覆层包含碳。The second cladding layer includes carbon.
除非另有说明，否则上述化学式中，当A为两种以上元素时，上述对于y数值范围的限定不仅是对每种作为A的元素的化学计量数的限定，也是对各个作为A的元素的化学计量数之和的限定。例如当A为两种以上元素A1、A2……An时，A1、A2……An各自的化学计量数y1、y2……yn各自均需落入本申请对y限定的数值范围内，且y1、y2……yn之和也需落入该数值范围内。类似地，对于R为两种以上元素的情况，本申请中对R化学计量数的数值范围的限定也具有上述含义。Unless otherwise stated, in the above chemical formula, when A is two or more elements, the above-mentioned limitation on the numerical range of y is not only a limitation on the stoichiometric number of each element as A, but also a limitation on each element as A. Limitation of the sum of stoichiometric numbers. For example, when A is two or more elements A1, A2...An, the stoichiometric numbers y1, y2...yn of A1, A2...An each need to fall within the numerical range defined by the application for y, and y1 The sum of , y2 ... yn also needs to fall within this value range. Similarly, for the case where R is two or more elements, the limitation of the numerical range of the stoichiometric number of R in this application also has the above meaning.
如图1所示，本申请的磷酸锰锂正极活性材料为具有两层包覆层的核-壳结构，其中内核包括Li 1+xMn 1-yA yP 1-zR zO 4。所述内核在磷酸锰锂的锰位掺杂的元素A有助于减小脱嵌锂过程中磷酸锰锂的晶格变化率，提高磷酸锰锂正极材料的结构稳定性，大大减少锰的溶出并降 低颗粒表面的氧活性。在磷位掺杂的元素R有助于改变Mn-O键长变化的难易程度，从而降低锂离子迁移势垒，促进锂离子迁移，提高二次电池的倍率性能。 As shown in FIG. 1 , the lithium manganese phosphate positive electrode active material of the present application has a core-shell structure with two cladding layers, wherein the inner core includes Li 1+x Mn 1-y A y P 1-z R z O 4 . The element A doped at the manganese position of lithium manganese phosphate in the inner core helps to reduce the lattice change rate of lithium manganese phosphate during lithium deintercalation, improves the structural stability of lithium manganese phosphate cathode material, and greatly reduces the dissolution of manganese And reduce the oxygen activity on the particle surface. The element R doped at the phosphorus site helps to change the difficulty of the change of the Mn-O bond length, thereby reducing the migration barrier of lithium ions, promoting the migration of lithium ions, and improving the rate performance of the secondary battery.
本申请的正极活性材料的第一包覆层包括焦磷酸盐和磷酸盐。由于过渡金属在焦磷酸盐中的迁移势垒较高(＞1eV)，能够有效抑制过渡金属的溶出。而磷酸盐具有优异的导锂离子的能力，并可减少表面杂锂含量。另外，由于第二包覆层为含碳层，因而能够有效改善LiMnPO 4的导电性能和去溶剂化能力。此外，第二包覆层的“屏障”作用可以进一步阻碍锰离子迁移到电解液中，并减少电解液对活性材料的腐蚀。 The first coating layer of the positive electrode active material of the present application includes pyrophosphate and phosphate. Due to the high migration barrier (>1eV) of transition metals in pyrophosphate, the dissolution of transition metals can be effectively suppressed. Phosphate has an excellent ability to conduct lithium ions, and can reduce the content of lithium impurities on the surface. In addition, since the second cladding layer is a carbon-containing layer, it can effectively improve the electrical conductivity and desolvation ability of LiMnPO 4 . In addition, the "barrier" effect of the second cladding layer can further hinder the migration of manganese ions into the electrolyte and reduce the corrosion of the active materials by the electrolyte.
因此，本申请通过对磷酸锰锂进行特定的元素掺杂和表面包覆，能够有效抑制脱嵌锂过程中的Mn溶出，同时促进锂离子的迁移，从而改善电芯的倍率性能，提高二次电池的循环性能和高温性能。Therefore, by performing specific element doping and surface coating on lithium manganese phosphate, this application can effectively suppress the dissolution of Mn in the process of lithium intercalation and deintercalation, and at the same time promote the migration of lithium ions, thereby improving the rate performance of the battery cell and increasing the secondary The cycle performance and high temperature performance of the battery.
需要指出的是，如图2所示，本申请中通过对比LiMnPO 4掺杂前后XRD谱图，可见，本申请的正极活性材料与LiMnPO 4掺杂前的主要特征峰的位置基本一致，说明掺杂的磷酸锰锂正极活性材料没有杂质相，二次电池性能的改善主要来自元素掺杂，而不是杂质相导致的。 It should be pointed out that, as shown in Figure 2, by comparing the XRD spectra before and after doping of LiMnPO in the present application, it can be seen that the positive electrode active material of the present application is basically consistent with the positions of the main characteristic peaks before doping of LiMnPO, indicating that doping The mixed lithium manganese phosphate positive electrode active material has no impurity phase, and the improvement of the performance of the secondary battery is mainly caused by element doping, not the impurity phase.
在一些实施方式中，可选地，所述第一包覆层的磷酸盐的晶面间距为0.345-0.358nm，晶向(111)的夹角为24.25°-26.45°；第一包覆层焦磷酸盐的晶面间距为0.293-0.326nm，晶向(111)的夹角为26.41°-32.57°。In some embodiments, optionally, the interplanar spacing of the phosphate of the first cladding layer is 0.345-0.358nm, and the included angle of the crystal direction (111) is 24.25°-26.45°; the first cladding layer The interplanar distance of pyrophosphate is 0.293-0.326nm, and the included angle of crystal direction (111) is 26.41°-32.57°.
当第一包覆层中磷酸盐和焦磷酸盐的晶面间距和晶向(111)的夹角在上述范围时，能够有效避免包覆层中的杂质相，从而提升材料的克容量，循环性能和倍率性能。When the interplanar spacing of phosphate and pyrophosphate in the first cladding layer and the included angle of crystal orientation (111) are in the above range, the impurity phase in the cladding layer can be effectively avoided, thereby increasing the gram capacity of the material, and cycle performance and rate performance.
在一些实施方式中，可选地，在所述内核中，y与1-y的比值为1∶10至10∶1，可选为1∶4至1∶1。此处y表示Mn位掺杂元素的化学计量数之和。在满足上述条件时，正极活性材料的能量密度和循环性能可进一步提升。In some embodiments, optionally, in the kernel, the ratio of y to 1-y is 1:10 to 10:1, optionally 1:4 to 1:1. Here y represents the sum of stoichiometric numbers of Mn-site doping elements. When the above conditions are met, the energy density and cycle performance of the positive electrode active material can be further improved.
在一些实施方式中，可选地，在所述内核中，z与1-z的比值为 1∶9至1∶999，可选为1∶499至1∶249。此处y表示P位掺杂元素的化学计量数之和。在满足上述条件时，正极活性材料的能量密度和循环性能可进一步提升。In some embodiments, optionally, in the kernel, the ratio of z to 1-z is 1:9 to 1:999, optionally 1:499 to 1:249. Here y represents the sum of the stoichiometric numbers of the P-site doping elements. When the above conditions are met, the energy density and cycle performance of the positive electrode active material can be further improved.
在一些实施方式中，可选地，所述第一包覆层的包覆量为大于0重量％且小于等于7重量％，可选为4-5.6重量％，基于所述内核的重量计。In some embodiments, optionally, the coating amount of the first coating layer is greater than 0% by weight and less than or equal to 7% by weight, optionally 4-5.6% by weight, based on the weight of the inner core.
当所述第一包覆层的包覆量在上述范围内时，能够进一步抑制锰溶出，同时进一步促进锂离子的传输。并能够有效避免以下情况：若第一包覆层的包覆量过小，则可能会导致焦磷酸盐对锰溶出的抑制作用不充分，同时对锂离子传输性能的改善也不显著；若第一包覆层的包覆量过大，则可能会导致包覆层过厚，增大电池阻抗，影响电池的动力学性能。When the coating amount of the first coating layer is within the above range, the dissolution of manganese can be further suppressed, and at the same time, the transport of lithium ions can be further promoted. And it can effectively avoid the following situation: if the coating amount of the first coating layer is too small, it may cause insufficient inhibition of pyrophosphate on manganese dissolution, and the improvement of lithium ion transport performance is not significant; If the coating amount of the first coating layer is too large, the coating layer may be too thick, which increases the battery impedance and affects the kinetic performance of the battery.
在一些实施方式中，可选地，所述第一包覆层中焦磷酸盐和磷酸盐的重量比为1∶3至3∶1，可选为1∶3至1∶1。In some embodiments, optionally, the weight ratio of pyrophosphate to phosphate in the first coating layer is 1:3 to 3:1, optionally 1:3 to 1:1.
焦磷酸盐和磷酸盐的合适配比有利于充分发挥二者的协同作用。并能够有效避免以下情况：如果焦磷酸盐过多而磷酸盐过少，则可能导致电池阻抗增大；如果磷酸盐过多而焦磷酸盐过少，则抑制锰溶出的效果不显著。The proper ratio of pyrophosphate and phosphate is conducive to giving full play to the synergistic effect of the two. And it can effectively avoid the following situations: if there is too much pyrophosphate and too little phosphate, it may lead to an increase in battery impedance; if there is too much phosphate and too little pyrophosphate, the effect of inhibiting the dissolution of manganese is not significant.
在一些实施方式中，可选地，所述焦磷酸盐和磷酸盐的结晶度各自独立地为10％至100％，可选为50％至100％。In some embodiments, optionally, the crystallinity of the pyrophosphate salt and the phosphate salt is each independently 10% to 100%, optionally 50% to 100%.
在本申请磷酸锰锂正极活性材料的第一包覆层中，具备一定结晶度的焦磷酸盐和磷酸盐有利于保持第一包覆层的结构稳定，减少晶格缺陷。这一方面有利于充分发挥焦磷酸盐阻碍锰溶出的作用，另一方面也有利于磷酸盐减少表面杂锂含量、降低表面氧的价态，从而减少正极材料与电解液的界面副反应，减少对电解液的消耗，改善电池的循环性能和安全性能。In the first coating layer of the lithium manganese phosphate positive electrode active material of the present application, pyrophosphate and phosphate with a certain degree of crystallinity are beneficial to keep the structure of the first coating layer stable and reduce lattice defects. On the one hand, this is beneficial to give full play to the role of pyrophosphate in hindering the dissolution of manganese. On the other hand, it is also beneficial to phosphate to reduce the content of lithium on the surface and the valence state of oxygen on the surface, thereby reducing the interface side reactions between the positive electrode material and the electrolyte, and reducing the The consumption of electrolyte improves the cycle performance and safety performance of the battery.
需要说明的是，在本申请中，焦磷酸盐和磷酸盐的结晶度例如可通过调整烧结过程的工艺条件例如烧结温度、烧结时间等进行调节。焦磷酸盐和磷酸盐的结晶度可通过本领域中已知的方法测量，例如通过X射线衍射法、密度法、红外光谱法、差示扫描量热法和核磁共 振吸收方法等方法测量。It should be noted that, in this application, the crystallinity of pyrophosphate and phosphate can be adjusted, for example, by adjusting the process conditions of the sintering process, such as sintering temperature, sintering time, and the like. The crystallinity of pyrophosphate and phosphate salts can be measured by methods known in the art, such as by X-ray diffraction, densitometry, infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance absorption methods.
在一些实施方式中，可选地，所述第二包覆层的包覆量为大于0重量％且小于等于6重量％，可选为3-5重量％，基于所述内核的重量计。In some embodiments, optionally, the coating amount of the second coating layer is greater than 0% by weight and less than or equal to 6% by weight, optionally 3-5% by weight, based on the weight of the inner core.
作为第二包覆层的含碳层一方面可以发挥“屏障”功能，避免正极活性材料与电解液直接接触，从而减少电解液对活性材料的腐蚀，提高电池在高温下的安全性能。另一方面，其具备较强的导电能力，可降低电池内阻，从而改善电池的动力学性能。然而，由于碳材料的克容量较低，因此当第二包覆层的用量过大时，可能会降低正极活性材料整体的克容量。因此，第二包覆层的包覆量在上述范围时，能够在不牺牲正极活性材料克容量的前提下，进一步改善电池的动力学性能和安全性能。On the one hand, the carbon-containing layer as the second coating layer can play a "barrier" function to avoid direct contact between the positive electrode active material and the electrolyte, thereby reducing the corrosion of the active material by the electrolyte and improving the safety performance of the battery at high temperatures. On the other hand, it has strong electrical conductivity, which can reduce the internal resistance of the battery, thereby improving the kinetic performance of the battery. However, since the gram capacity of the carbon material is low, when the amount of the second coating layer is too large, the gram capacity of the entire positive electrode active material may be reduced. Therefore, when the coating amount of the second coating layer is in the above range, the kinetic performance and safety performance of the battery can be further improved without sacrificing the gram capacity of the positive electrode active material.
在一些实施方式中，可选地，所述A选自Fe、Ti、V、Ni、Co和Mg中的至少两种。In some embodiments, optionally, the A is selected from at least two of Fe, Ti, V, Ni, Co and Mg.
在磷酸锰锂正极活性材料中的锰位同时掺杂两种以上的上述元素有利于增强掺杂效果，一方面进一步减小晶格变化率，从而抑制锰的溶出，减少电解液和活性锂的消耗，另一方面也有利于进一步降低表面氧活性，减少正极活性材料与电解液的界面副反应，从而改善电池的循环性能和高温储存性能。Simultaneously doping two or more of the above-mentioned elements on the manganese site in the lithium manganese phosphate positive electrode active material is beneficial to enhance the doping effect, on the one hand, further reduce the lattice change rate, thereby inhibiting the dissolution of manganese, and reducing the electrolyte and active lithium. On the other hand, it is also beneficial to further reduce the surface oxygen activity and reduce the interface side reaction between the positive electrode active material and the electrolyte, thereby improving the cycle performance and high temperature storage performance of the battery.
在一些实施方式中，可选地，所述正极活性材料的Li/Mn反位缺陷浓度为4％以下，可选为2％以下。In some embodiments, optionally, the Li/Mn antisite defect concentration of the positive electrode active material is less than 4%, optionally less than 2%.
在本申请的正极活性材料中，Li/Mn反位缺陷是指LiMnPO 4晶格中，Li +和Mn 2+的位置发生互换。由于Li +传输通道为一维通道，Mn 2+在Li +传输通道中难以迁移，因此，反位缺陷的Mn 2+会阻碍Li +的传输。通过将Li/Mn反位缺陷浓度控制在低水平，能够改善LiMnPO 4的克容量和倍率性能。本申请中，反位缺陷浓度例如可根据JIS K 0131-1996测定。 In the positive electrode active material of the present application, the Li/Mn antisite defect means that in the LiMnPO 4 lattice, the positions of Li + and Mn 2+ are exchanged. Since the Li + transport channel is a one-dimensional channel, Mn 2+ is difficult to migrate in the Li + transport channel, so the Mn 2+ with antisite defects will hinder the transport of Li + . The gram capacity and rate performance of LiMnPO4 can be improved by controlling the Li/Mn antisite defect concentration at a low level. In the present application, the antisite defect concentration can be measured according to JIS K 0131-1996, for example.
在一些实施方式中，可选地，所述正极活性材料的晶格变化率为6％以下，可选为4％以下。In some embodiments, optionally, the lattice change rate of the positive electrode active material is less than 6%, optionally less than 4%.
LiMnPO 4的脱嵌锂过程是两相反应。两相的界面应力由晶格变化 率大小决定，晶格变化率越小，界面应力越小，Li +传输越容易。因此，减小内核的晶格变化率将有利于增强Li +的传输能力，从而改善二次电池的倍率性能。 The lithium-deintercalation process of LiMnPO 4 is a two-phase reaction. The interfacial stress of the two phases is determined by the lattice change rate. The smaller the lattice change rate, the smaller the interfacial stress and the easier Li + transport. Therefore, reducing the lattice change rate of the inner core will be beneficial to enhance the Li + transport ability, thereby improving the rate performance of secondary batteries.
在一些实施方式中，可选地，所述正极活性材料的扣电平均放电电压为3.5V以上，放电克容量在140mAh/g以上；可选为平均放电电压3.6V以上，放电克容量在145mAh/g以上。In some embodiments, optionally, the average discharge voltage of the positive electrode active material is above 3.5V, and the discharge gram capacity is above 140mAh/g; optionally, the average discharge voltage is above 3.6V, and the discharge gram capacity is above 145mAh /g or more.
尽管未掺杂的LiMnPO 4的平均放电电压在4.0V以上，但它的放电克容量较低，通常小于120mAh/g，因此，能量密度较低；通过掺杂调整晶格变化率，可使其放电克容量大幅提升，在平均放电电压微降的情况下，整体能量密度有明显升高。 Although the average discharge voltage of undoped LiMnPO 4 is above 4.0V, its discharge gram capacity is low, usually less than 120mAh/g, so the energy density is low; adjusting the lattice change rate by doping can make it The discharge gram capacity has been greatly improved, and the overall energy density has increased significantly under the condition of a slight drop in the average discharge voltage.
在一些实施方式中，可选地，所述正极活性材料的表面氧价态为-1.88以下，可选地为-1.98～-1.88。In some embodiments, optionally, the surface oxygen valence state of the positive electrode active material is below -1.88, optionally between -1.98 and -1.88.
这是由于氧在化合物中的价态越高，其得电子能力越强，即氧化性越强。而在本申请的磷酸锰锂正极活性材料中，通过将氧的表面价态控制在较低水平，可降低正极材料表面的反应活性，减少正极材料与电解液的界面副反应，从而改善二次电池的循环性能和高温储存性能。This is because the higher the valence state of oxygen in the compound, the stronger its ability to obtain electrons, that is, the stronger the oxidation. In the lithium manganese phosphate positive electrode active material of the present application, by controlling the surface valence state of oxygen at a lower level, the reactivity of the surface of the positive electrode material can be reduced, and the interface side reaction between the positive electrode material and the electrolyte can be reduced, thereby improving the secondary The cycle performance and high temperature storage performance of the battery.
在一些实施方式中，可选地，所述正极活性材料在3吨(T)下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。 In some embodiments, optionally, the positive electrode active material has a compacted density at 3 tons (T) of 2.0 g/cm 3 or more, optionally 2.2 g/cm 3 or more.
正极活性材料的压实密度越高，即单位体积活性物质的重量越大，将更有利于提升电池的体积能量密度。本申请中，压实密度例如可根据GB/T 24533-2009测定。The higher the compaction density of the positive electrode active material, that is, the greater the weight of the active material per unit volume, it will be more conducive to improving the volumetric energy density of the battery. In the present application, the compacted density can be measured according to GB/T 24533-2009, for example.
本申请的第二方面提供本申请的第一方面的正极活性材料的制备方法，其包括以下步骤：The second aspect of the present application provides the preparation method of the positive electrode active material of the first aspect of the present application, which comprises the following steps:
提供内核材料的步骤：所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； Step of providing core material: the core comprises Li 1+x Mn 1-y A y P 1-z R z O 4 , where x=-0.100-0.100, y=0.001-0.500, z=0.001-0.100, the Said A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and may be One or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
包覆步骤：提供MP 2O 7粉末和包含碳的源的XPO 4悬浊液，将所 述内核材料、MP 2O 7粉末加入到包含碳的源的XPO 4悬浊液中并混合，经烧结获得正极活性材料，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Coating step: provide MP 2 O 7 powder and XPO 4 suspension containing carbon source, add the core material, MP 2 O 7 powder into XPO 4 suspension containing carbon source and mix, Sintering to obtain a positive electrode active material, wherein the M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al;
其中，所述正极活性材料具有核-壳结构，其包括内核及包覆所述内核的壳，所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，所述第二包覆层包含碳。 Wherein, the positive electrode active material has a core-shell structure, which includes an inner core and a shell covering the inner core, and the shell includes a first cladding layer covering the inner core and a shell covering the first cladding layer. The second coating layer, the first coating layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , and the second coating layer includes carbon.
本申请的制备方法对材料的来源没有特别的限制。可选地，本申请制备方法中的内核材料可以是市售获得的，也可以是通过本申请的方法制备获得的。可选地，所述内核材料通过下文中所述方法制备获得。The preparation method of the present application has no special limitation on the source of the material. Optionally, the core material in the preparation method of the present application may be commercially available, or prepared by the method of the present application. Optionally, the core material is prepared by the method described below.
在一些实施方式中，可选地，提供内核材料的步骤包括以下步骤：In some embodiments, optionally, the step of providing the core material comprises the following steps:
步骤(1)：将锰的源、元素A的源和酸在容器中混合并搅拌，得到掺杂有元素A的锰盐颗粒；Step (1): mixing and stirring a source of manganese, a source of element A, and an acid in a container to obtain manganese salt particles doped with element A;
步骤(2)：将所述掺杂有元素A的锰盐颗粒与锂的源、磷的源和元素R的源在溶剂中混合并得到浆料，在惰性气体气氛保护下烧结后得到掺杂有元素A和元素R的磷酸锰锂，其中，所述掺杂有元素A和元素R的磷酸锰锂为Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种。 Step (2): Mix the manganese salt particles doped with element A with a source of lithium, a source of phosphorus and a source of element R in a solvent to obtain a slurry, which is sintered under the protection of an inert gas atmosphere to obtain a doped Lithium manganese phosphate with element A and element R, wherein the lithium manganese phosphate doped with element A and element R is Li 1+x Mn 1-y A y P 1-z R z O 4 , where x= -0.100-0.100, y=0.001-0.500, z=0.001-0.100, said A is selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, One or more of Sn, Sb, Nb and Ge, optionally one or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from B, Si, N and S one or more of .
在一些实施方式中，可选地，所述步骤(1)在20-120℃，可选为25-80℃的温度下进行；和/或，In some embodiments, optionally, the step (1) is carried out at a temperature of 20-120°C, optionally 25-80°C; and/or,
所述步骤(1)中所述搅拌在500-700rpm下进行60-420分钟，可选地为120-360分钟。The stirring in the step (1) is carried out at 500-700 rpm for 60-420 minutes, optionally for 120-360 minutes.
通过控制掺杂时的反应温度、搅拌速率和混合时间，能够使掺杂元素均匀分布，减少晶格缺陷，抑制锰溶出，减少正极活性材料与电解液的界面副反应，从而可提升材料的克容量和倍率性能等。By controlling the reaction temperature, stirring rate and mixing time during doping, the doping elements can be evenly distributed, the lattice defects can be reduced, the dissolution of manganese can be suppressed, and the interface side reaction between the positive electrode active material and the electrolyte can be reduced, thereby improving the grammage of the material. capacity and rate performance, etc.
需要说明的是，在本申请中，某种元素的来源可包括该元素的单 质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物中的一种或多种，前体是该来源可实现本申请制备方法的目的。作为示例，所述元素A的源选自元素A的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物中的一种或多种；和/或，所述元素R的源选自元素R的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物以及元素R的无机酸中的一种或多种。It should be noted that, in this application, the source of a certain element may include one or more of elemental elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides of the element. The body is the source that can realize the purpose of the preparation method of the present application. As an example, the source of the element A is selected from one or more of element A, sulfate, halide, nitrate, organic acid salt, oxide or hydroxide; and/or, the element The source of R is selected from one or more of elemental R elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides, and inorganic acids of element R.
在一些实施方式中，可选地，本申请中锰的源为选自单质锰、二氧化锰、磷酸锰、草酸锰、碳酸锰中的一种或多种。In some embodiments, optionally, the source of manganese in the present application is one or more selected from elemental manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate.
在一些实施方式中，可选地，元素A为铁，并且可选地，铁的源为选自碳酸亚铁、氢氧化铁、硫酸亚铁中的一种或多种。In some embodiments, optionally, element A is iron, and optionally, the source of iron is one or more selected from ferrous carbonate, ferric hydroxide, and ferrous sulfate.
在一些实施方式中，可选地，在步骤(1)中，所述酸选自盐酸、硫酸、硝酸、磷酸、有机酸如草酸等中的一种或多种，可选为草酸。在一些实施方式中，所述酸为浓度为60重量％以下的稀酸。In some embodiments, optionally, in step (1), the acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, organic acids such as oxalic acid, etc., and may be oxalic acid. In some embodiments, the acid is a dilute acid having a concentration of 60% by weight or less.
在一些实施方式中，可选地，元素R的无机酸选自磷酸、硝酸、硼酸、亚硅酸、原硅酸中的一种或多种。In some embodiments, optionally, the mineral acid of element R is selected from one or more of phosphoric acid, nitric acid, boric acid, silicic acid, ortho silicic acid.
在一些实施方式中，可选地，本申请中锂的源为选自碳酸锂、氢氧化锂、磷酸锂、磷酸二氢锂中的一种或多种。In some embodiments, optionally, the source of lithium in the present application is one or more selected from lithium carbonate, lithium hydroxide, lithium phosphate, and lithium dihydrogen phosphate.
在一些实施方式中，可选地，本申请中磷的源为选自磷酸氢二铵、磷酸二氢铵、磷酸铵和磷酸中的一种或多种。In some embodiments, optionally, the source of phosphorus in the present application is one or more selected from diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate and phosphoric acid.
在一些实施方式中，可选地，本申请中的碳的源为有机碳源，并且所述有机碳源选自淀粉、蔗糖、葡萄糖、聚乙烯醇、聚乙二醇、柠檬酸中的一种或多种。In some embodiments, optionally, the source of carbon in the present application is an organic carbon source, and the organic carbon source is selected from one of starch, sucrose, glucose, polyvinyl alcohol, polyethylene glycol, and citric acid. one or more species.
在一些实施方式中，可选地，本申请所述制备方法中使用的溶剂为本领域通常使用的溶剂。例如，本申请制备方法中的溶剂可各自独立地选自乙醇、水(例如去离子水)中的至少一种。In some embodiments, optionally, the solvent used in the preparation method described in the present application is a solvent commonly used in the art. For example, the solvents in the preparation method of the present application can be independently selected from at least one of ethanol and water (eg, deionized water).
在一些实施方式中，可选地，在制备A元素掺杂的锰盐颗粒的过程中，控制溶液pH为4-6。需要说明的是，在本申请中可通过本领域通常使用的方法调节所得混合物的pH，例如可通过添加酸或碱。In some embodiments, optionally, during the preparation of element A-doped manganese salt particles, the pH of the solution is controlled to be 4-6. It should be noted that in this application, the pH of the resulting mixture can be adjusted by methods commonly used in the art, for example, by adding acid or base.
在一些实施方式中，可选地，在步骤(2)中，所述锰盐颗粒与锂的源、磷的源的摩尔比为1∶0.5-2.1∶0.5-2.1。In some embodiments, optionally, in step (2), the molar ratio of the manganese salt particles to the source of lithium and the source of phosphorus is 1:0.5-2.1:0.5-2.1.
在一些实施方式中，可选地，在步骤(2)中，烧结条件为：在惰性气体或惰性气体与氢气混合气氛下在600-800℃下烧结4-10小时。In some embodiments, optionally, in step (2), the sintering condition is: sintering at 600-800° C. for 4-10 hours in an atmosphere of inert gas or a mixture of inert gas and hydrogen.
在一些实施方式中，可选地，惰性气体与氢气混合物为氮气(70-90体积％)+氢气(10-30体积％)。In some embodiments, optionally, the mixture of inert gas and hydrogen is nitrogen (70-90 volume %)+hydrogen (10-30 volume %).
在一些实施方式中，可选地，所述MP 2O 7粉末是市售产品，或者可选地，所述MP 2O 7粉末通过以下方法制备：将元素M的源和磷的源添加到溶剂中，得到混合物，调节混合物的pH为4-6，搅拌并充分反应，然后经干燥、烧结获得，其中M选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种。 In some embodiments, optionally, the MP 2 O 7 powder is a commercially available product, or alternatively, the MP 2 O 7 powder is prepared by adding a source of element M and a source of phosphorus to In the solvent, the mixture is obtained, the pH of the mixture is adjusted to 4-6, stirred and fully reacted, then obtained by drying and sintering, wherein M is selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr , Nb or Al in one or more.
在一些实施方式中，可选地，在MP 2O 7粉末的制备过程中，所述干燥步骤为在100-300℃、可选150-200℃下干燥4-8h。 In some embodiments, optionally, during the preparation of MP 2 O 7 powder, the drying step is drying at 100-300°C, optionally 150-200°C, for 4-8h.
在一些实施方式中，可选地，在MP 2O 7粉末的制备过程中，所述烧结步骤为在500-800℃、可选650-800℃下，在惰性气体气氛下烧结4-10h。 In some embodiments, optionally, during the preparation of MP 2 O 7 powder, the sintering step is sintering at 500-800° C., optionally 650-800° C., in an inert gas atmosphere for 4-10 hours.
在一些实施方式中，可选地，所述包含碳的源的XPO 4悬浊液是市售可得的，或者可选地，通过以下方法来制备：将锂的源、X的源、磷的源和碳的源在溶剂中混合均匀，然后将反应混合物升温至60-120℃保持2-8小时即可获得包含碳的源的XPO 4悬浊液。可选地，在制备包含碳的源的XPO 4悬浊液的过程中，调节所述混合物的pH为4-6。 In some embodiments, optionally, the XPO suspension comprising a source of carbon is commercially available, or alternatively, is prepared by combining a source of lithium, a source of X, phosphorus The source of carbon and the source of carbon are uniformly mixed in a solvent, and then the reaction mixture is heated to 60-120° C. for 2-8 hours to obtain the XPO 4 suspension containing the source of carbon. Optionally, during the preparation of the XPO 4 suspension comprising the source of carbon, the pH of the mixture is adjusted to 4-6.
在一些实施方式中，可选地，在步骤(3)中，所述A元素和R元素掺杂的磷酸锰锂、MP 2O 7粉末和包含碳的源的XPO 4悬浊液的质量比为：1∶(0.001-0.05)∶(0.001-0.05)。 In some embodiments, optionally, in step (3), the mass ratio of the lithium manganese phosphate doped with the A element and the R element, MP 2 O 7 powder and XPO 4 suspension containing carbon source It is: 1:(0.001-0.05):(0.001-0.05).
在一些实施方式中，可选地，所述包覆步骤中烧结温度为500-800℃，烧结时间为4-10h。In some embodiments, optionally, in the cladding step, the sintering temperature is 500-800° C., and the sintering time is 4-10 h.
在一些实施方式中，可选地，本申请双层包覆的磷酸锰锂正极活性材料的一次颗粒的中值粒径Dv50为50-2000nm。In some embodiments, optionally, the median particle diameter Dv50 of the primary particles of the double-layer coated lithium manganese phosphate positive electrode active material of the present application is 50-2000 nm.
[正极极片][Positive pole piece]
本申请的第三方面提供一种正极极片，其包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请 第一方面的磷酸锰锂正极活性材料或根据本申请第二方面的方法制备的磷酸锰锂正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。The third aspect of the present application provides a positive electrode sheet, which includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the lithium manganese phosphate positive electrode active material according to the first aspect of the present application Or the lithium manganese phosphate positive electrode active material prepared according to the method of the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
在一些实施方式中，可选地，所述正极活性材料在所述正极膜层中的含量为90-99.5重量％，基于所述正极膜层的总重量计。In some embodiments, optionally, the content of the positive electrode active material in the positive electrode film layer is 90-99.5% by weight, based on the total weight of the positive electrode film layer.
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。As an example, the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid Formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。In some embodiments, the positive electrode film layer may also optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
在一些实施方式中，本申请的正极膜层包括90-99.5％的本申请第一方面的磷酸锰锂正极活性材料、0.4-5.5％的粘结剂、0.1-2.5％的导电碳和0.001-1％的其他添加剂，基于所述正极膜层的总重量计。In some embodiments, the positive electrode film layer of the present application includes 90-99.5% of the lithium manganese phosphate positive electrode active material of the first aspect of the present application, 0.4-5.5% of the binder, 0.1-2.5% of the conductive carbon and 0.001- 1% of other additives, based on the total weight of the positive film layer.
在一些实施方式中，可选地，本申请的正极膜层中还可包括其他添加剂如分散剂、润湿剂、流变改性剂等本领域通常使用的添加剂。In some embodiments, optionally, the positive electrode film layer of the present application may also include other additives such as dispersants, wetting agents, rheology modifiers and other additives commonly used in this field.
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意 其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。In some embodiments, the positive electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
在一些实施方式中，本申请正极膜层的涂覆重量为0.28-0.45g/1540.25mm 2，压实密度达到2.2-2.8g/cm 3。 In some embodiments, the coating weight of the anode film layer of the present application is 0.28-0.45g/1540.25mm 2 , and the compacted density reaches 2.2-2.8g/cm 3 .
[负极极片][Negative pole piece]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。As an example, the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。In some embodiments, the negative electrode current collector can use a metal foil or a composite current collector. For example, copper foil can be used as the metal foil. The composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material. Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。In some embodiments, the negative electrode active material can be a negative electrode active material known in the art for 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 material, tin-based material, lithium titanate, and the like. The silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。In some embodiments, the negative electrode film layer may further optionally include a binder. The binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。In some embodiments, the negative electrode film layer may also optionally include a conductive agent. The conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。In some embodiments, the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。In some embodiments, the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
[电解质][Electrolyte]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。The electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece. The present application has no specific limitation on the type of electrolyte, which can be selected according to requirements. For example, electrolytes can be liquid, gel or all solid.
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。In some embodiments, the electrolyte is an electrolytic solution. The electrolyte solution includes an electrolyte salt and a solvent.
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。In some embodiments, the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1，4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。In some embodiments, the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
[隔离膜][Isolation film]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。In some embodiments, a separator is further included in the secondary battery. The present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。In some embodiments, the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。In some embodiments, the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
[二次电池][Secondary battery]
本申请第四方面提供一种二次电池，其包括本申请第一方面所述的正极活性材料或通过本申请第二方面所述的方法制备的正极活性材料或本申请第三方面所述的正极极片。The fourth aspect of the application provides a secondary battery, which includes the positive electrode active material described in the first aspect of the application or the positive electrode active material prepared by the method described in the second aspect of the application or the positive electrode active material described in the third aspect of the application Positive pole piece.
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。Typically, a secondary battery includes a positive pole piece, a negative pole piece, an electrolyte, and a separator. During the charging and discharging process of the battery, active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode. The electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece. The separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
在一些实施方式中，锂离子二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。In some embodiments, a lithium ion secondary battery may include an outer package. The outer package can be used to package the above-mentioned electrode assembly and electrolyte.
在一些实施方式中，锂离子二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。锂离子二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)以及聚丁二酸丁二醇酯(PBS)等。In some embodiments, the outer package of the lithium-ion secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like. The outer packaging of the lithium-ion secondary battery may also be a soft bag, such as a pouch-type soft bag. The material of the soft bag may be plastic, and examples of plastic include polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。In addition, the secondary battery, the battery module, the battery pack, and the power consumption device of the present application will be described below with appropriate reference to the accompanying drawings.
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方 形或其他任意的形状。例如，图3是作为一个示例的方形结构的二次电池5。The present application has no special limitation on the shape of the secondary battery, which may be cylindrical, square or any other shape. For example, FIG. 3 shows a square-shaped secondary battery 5 as an example.
在一些实施方式中，参照图4，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。In some embodiments, referring to FIG. 4 , the outer package may include a housing 51 and a cover 53 . Wherein, the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity. The housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity. The positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is packaged in the accommodating cavity. Electrolyte is infiltrated in the electrode assembly 52 . The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
在一些实施方式中，锂离子二次电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。In some embodiments, the lithium-ion secondary battery can be assembled into a battery module, and the number of lithium-ion batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
图5是作为一个示例的电池模块4。参照图5，在电池模块4中，多个锂离子电池5可以沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个锂离子电池5进行固定。FIG. 5 is a battery module 4 as an example. Referring to FIG. 5 , in the battery module 4 , a plurality of lithium-ion batteries 5 can be arranged sequentially along the length direction of the battery module 4 . Of course, it can also be arranged in any other manner. Further, the plurality of lithium ion batteries 5 can be fixed by fasteners.
可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。Optionally, the battery module 4 may also include a housing with an accommodating space, and a plurality of lithium-ion batteries 5 are accommodated in the accommodating space.
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。In some embodiments, the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
图6和图7是作为一个示例的电池包1。参照图6和图7，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。6 and 7 show the battery pack 1 as an example. Referring to FIGS. 6 and 7 , the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 . Multiple battery modules 4 can be arranged in the battery box in any manner.
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手 机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。In addition, the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device. The electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。As the electric device, a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
图8是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。FIG. 8 is an example of an electrical device. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the electric device for the secondary battery, a battery pack or a battery module may be used.
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。As another example, a device may be a cell phone, tablet, laptop, or the like. The device is generally required to be light and thin, and a secondary battery can be used as a power source.
实施例Example
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。本发明实施例中各成分的含量，如果没有特别说明，均以不含结晶水的质量计。Hereinafter, examples of the present application will be described. The embodiments described below are exemplary and are only used for explaining the present application, and should not be construed as limiting the present application. If no specific technique or condition is indicated in the examples, it shall be carried out according to the technique or condition described in the literature in this field or according to the product specification. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products. The content of each component in the examples of the present invention is based on the mass without water of crystallization, unless otherwise specified.
本申请实施例涉及的原材料来源如下：The sources of raw materials involved in the embodiments of the present application are as follows:
名称name 化学式chemical formula 厂家factory 规格Specification
碳酸锰manganese carbonate MnCO 3 MnCO 3 山东西亚化学工业有限公司Shandong West Asia Chemical Industry Co., Ltd. 1Kg1Kg
碳酸锂lithium carbonate Li 2CO 3 Li 2 CO 3 山东西亚化学工业有限公司Shandong West Asia Chemical Industry Co., Ltd. 1Kg1Kg
碳酸镁magnesium carbonate MgCO 3 MgCO 3 山东西亚化学工业有限公司Shandong West Asia Chemical Industry Co., Ltd. 1Kg1Kg
碳酸锌zinc carbonate ZnCO 3 ZnCO 3 武汉鑫儒化工有限公司Wuhan Xinru Chemical Co., Ltd. 25Kg25Kg
碳酸亚铁Ferrous carbonate FeCO 3 FeCO 3 西安兰之光精细材料有限公司Xi'an Lanzhiguang Fine Materials Co., Ltd. 1Kg1Kg
硫酸镍nickel sulfate NiCO 3 NiCO 3 山东西亚化学工业有限公司Shandong West Asia Chemical Industry Co., Ltd. 1Kg1Kg
硫酸钛Titanium Sulfate Ti(SO 4) 2 Ti(SO 4 ) 2 山东西亚化学工业有限公司Shandong West Asia Chemical Industry Co., Ltd. 1Kg1Kg
硫酸钴cobalt sulfate CoSO 4 CoSO4 厦门志信化学有限公司Xiamen Zhixin Chemical Co., Ltd. 500g500g
二氯化钒Vanadium dichloride VCl 2 VCl 2 上海金锦乐实业有限公司Shanghai Jinjinle Industrial Co., Ltd. 1Kg1Kg
二水合草酸oxalic acid dihydrate C 2H 2O 4·2H 2O C 2 H 2 O 4 2H 2 O 上海金锦乐实业有限公司Shanghai Jinjinle Industrial Co., Ltd. 1Kg1Kg
磷酸二氢铵Ammonium dihydrogen phosphate NH 4H 2PO 4 NH 4 H 2 PO 4 上海澄绍生物科技有限公司Shanghai Chengshao Biotechnology Co., Ltd. 500g500g
蔗糖sucrose C 12H 22O 11 C 12 H 22 O 11 上海源叶生物科技有限公司Shanghai Yuanye Biotechnology Co., Ltd. 100g100g
硫酸sulfuric acid H 25O 4 H 2 5O 4 深圳海思安生物技术有限公司Shenzhen Hisian Biotechnology Co., Ltd. 质量分数60％Quality score 60%
硝酸nitric acid HNO 3 HNO 3 安徽凌天精细化工有限公司Anhui Lingtian Fine Chemical Co., Ltd. 质量分数60％Quality score 60%
亚硅酸Silicic acid H 2SiO 3 H 2 SiO 3 上海源叶生物科技有限公司Shanghai Yuanye Biotechnology Co., Ltd. 100g100g
硼酸boric acid H 3BO 3 H 3 BO 3 常州市启迪化工有限公司Changzhou Qidi Chemical Co., Ltd. 1Kg1Kg
实施例1-1Example 1-1
【双层包覆的磷酸锰锂正极活性材料的制备】[Preparation of double-layer coated lithium manganese phosphate cathode active material]
(1)共掺杂磷酸锰锂内核的制备(1) Preparation of co-doped lithium manganese phosphate core
制备Fe、Co和V共掺杂的草酸锰：将689.5g碳酸锰(以MnCO 3计，下同)、455.2g碳酸亚铁(以FeCO 3计，下同)、4.6g硫酸钴(以CoSO 4计，下同)和4.9g二氯化钒(以VCl 2计，下同)在混料机中充分混合6小时。将混合物转移至反应釜中，并加入5升去离子水和1260.6g二水合草酸(以C 2H 2O 4.2H 2O计，下同)。将反应釜加热至80℃，以600rpm的转速搅拌6小时，直至反应终止(无气泡产生)，得到Fe、Co、V和S共掺杂的草酸锰悬浮液。然后过滤所述悬浮液，将滤饼在120℃下烘干，之后进行研磨，得到中值粒径Dv50为100nm的Fe、Co和V共掺杂的二水草酸锰颗粒。 Prepare Fe, Co and V co-doped manganese oxalate: 689.5g manganese carbonate (calculated as MnCO3 , the same below), 455.2g ferrous carbonate (calculated as FeCO3 , the same below), 4.6g cobalt sulfate (calculated as CoSO 4 meter, the same below) and 4.9g vanadium dichloride (in VCl 2 meter, the same below) were fully mixed in the mixer for 6 hours. The mixture was transferred to a reaction kettle, and 5 liters of deionized water and 1260.6 g of oxalic acid dihydrate (calculated as C 2 H 2 O 4 .2H 2 O, the same below) were added. The reactor was heated to 80° C. and stirred at 600 rpm for 6 hours until the reaction was terminated (no bubbles were generated), and a Fe, Co, V and S co-doped manganese oxalate suspension was obtained. Then the suspension was filtered, the filter cake was dried at 120° C., and then ground to obtain Fe, Co and V co-doped manganese oxalate dihydrate particles with a median diameter Dv50 of 100 nm.
制备Fe、Co、V和S共掺杂的磷酸锰锂：将前一步骤获得的二水草酸锰颗粒(1793.4g)、369.0g碳酸锂(以Li 2CO 3计，下同)，1.6g浓度为60％的稀硫酸(以60％H 2SO 4计，下同)和1148.9g磷酸二氢铵(以NH 4H 2PO 4计，下同)加入到20升去离子水中，将混合物搅拌10小时使其混合均匀，得到浆料。将所述浆料转移到喷雾干燥设备中进行喷雾干燥造粒，设定干燥温度为250℃，干燥4小时，得到粉料。在氮气(90体积％)+氢气(10体积％)保护气氛中，将上述粉料在700℃下烧结4小时，得到1572.1g的Fe、Co、V和S共掺杂的磷酸锰锂。 Preparation of lithium manganese phosphate co-doped with Fe, Co, V and S: Manganese oxalate dihydrate particles (1793.4g) obtained in the previous step, 369.0g lithium carbonate (calculated as Li 2 CO 3 , the same below), 1.6g Concentration is 60% dilute sulfuric acid (calculated as 60% H 2 SO 4 , the same below) and 1148.9g ammonium dihydrogen phosphate (calculated as NH 4 H 2 PO 4 , the same below) are added to 20 liters of deionized water, and the mixture Stir for 10 hours to make it evenly mixed to obtain a slurry. The slurry was transferred to a spray drying device for spray drying and granulation. The drying temperature was set at 250° C. and dried for 4 hours to obtain a powder. In a protective atmosphere of nitrogen (90 volume %) + hydrogen (10 volume %), the above powder was sintered at 700° C. for 4 hours to obtain 1572.1 g of Fe, Co, V and S co-doped lithium manganese phosphate.
(2)焦磷酸铁锂和磷酸铁锂的制备(2) Preparation of lithium iron pyrophosphate and lithium iron phosphate
制备焦磷酸铁锂粉末：将4.77g碳酸锂、7.47g碳酸亚铁、14.84g磷酸二氢铵和1.3g二水合草酸溶于50ml去离子水中。混合物的pH为5，搅拌2小时使反应混合物充分反应。然后将反应后的溶液升温到80℃并保持该温度4小时，得到包含Li 2FeP 2O 7的悬浊液，将悬浊液进行过滤，用去离子水洗涤，并在120℃下干燥4h，得到粉末。将所述粉末在650℃、氮气气氛下烧结8小时，并自然冷却至室温后进行研磨，得到Li 2FeP 2O 7粉末。 Preparation of lithium iron pyrophosphate powder: 4.77 g of lithium carbonate, 7.47 g of ferrous carbonate, 14.84 g of ammonium dihydrogen phosphate and 1.3 g of oxalic acid dihydrate were dissolved in 50 ml of deionized water. The pH of the mixture was 5, and the reaction mixture was stirred for 2 hours to fully react. Then the temperature of the reacted solution was raised to 80°C and maintained at this temperature for 4 hours to obtain a suspension containing Li 2 FeP 2 O 7 , which was filtered, washed with deionized water, and dried at 120°C for 4 hours , to obtain powder. The powder was sintered at 650° C. under a nitrogen atmosphere for 8 hours, cooled naturally to room temperature, and then ground to obtain Li 2 FeP 2 O 7 powder.
制备磷酸铁锂悬浊液：将11.1g碳酸锂、34.8g碳酸亚铁、34.5g磷酸二氢铵、1.3g二水合草酸和74.6g蔗糖(以C 12H 22O 11计，下同)溶于150ml去离子水中，得到混合物，然后搅拌6小时使上述混合物充分反应。然后将反应后的溶液升温到120℃并保持该温度6小时，得到包含LiFePO 4的悬浊液。 Preparation of lithium iron phosphate suspension: dissolve 11.1g of lithium carbonate, 34.8g of ferrous carbonate, 34.5g of ammonium dihydrogen phosphate, 1.3g of oxalic acid dihydrate and 74.6g of sucrose (calculated as C 12 H 22 O 11 , the same below) The mixture was obtained in 150 ml of deionized water, and then stirred for 6 hours to fully react the above mixture. The reacted solution was then warmed up to 120 °C and kept at this temperature for 6 hours to obtain a suspension containing LiFePO4 .
(3)包覆(3) Coating
将1572.1g上述Fe、Co、V和S共掺杂的磷酸锰锂与15.72g上述焦磷酸铁锂(Li 2FeP 2O 7)粉末加入到上一步骤制备获得的磷酸铁锂(LiFePO 4)悬浊液中，搅拌混合均匀后转入真空烘箱中在150℃下干燥6小时。然后通过砂磨分散所得产物。在分散后，将所得产物在氮气气氛中、在700℃下烧结6小时，得到目标产物双层包覆的磷酸锰锂。 Add 1572.1g of the aforementioned Fe, Co, V and S co-doped lithium manganese phosphate and 15.72g of the aforementioned lithium iron pyrophosphate (Li 2 FeP 2 O 7 ) powder to the lithium iron phosphate (LiFePO 4 ) prepared in the previous step The suspension was stirred evenly and then transferred to a vacuum oven for drying at 150° C. for 6 hours. The resulting product was then dispersed by sand milling. After dispersion, the obtained product was sintered at 700° C. for 6 hours in a nitrogen atmosphere to obtain the target product double-coated lithium manganese phosphate.
【正极极片的制备】【Preparation of Positive Electrode】
将上述制备的双层包覆的磷酸锰锂正极活性材料、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比为92∶2.5∶5.5加入到N-甲基吡咯烷酮(NMP)中，搅拌混合均匀，得到正极浆料。然后将正极浆料按0.280g/1540.25mm 2均匀涂覆于铝箔上，经烘干、冷压、分切，得到正极极片。 The above-mentioned double-coated lithium manganese phosphate positive electrode active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) were added to N-methylpyrrolidone (NMP) in a weight ratio of 92:2.5:5.5 ), stir and mix evenly to obtain positive electrode slurry. Then, the positive electrode slurry was uniformly coated on the aluminum foil at a thickness of 0.280g/1540.25mm 2 , dried, cold pressed, and cut to obtain the positive electrode sheet.
【负极极片的制备】[Preparation of negative electrode sheet]
将负极活性物质人造石墨、硬碳、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照重量比为90∶ 5∶2∶2∶1溶于溶剂去离子水中，搅拌混合均匀后制备成负极浆料。将负极浆料按0.117g/1540.25mm 2均匀涂覆在负极集流体铜箔上，经过烘干、冷压、分切得到负极极片。 Negative electrode active material artificial graphite, hard carbon, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener carboxymethylcellulose sodium (CMC-Na) are 90: 5: 2: 2 according to weight ratio : 1 dissolved in deionized water as a solvent, stirred and mixed evenly to prepare negative electrode slurry. The negative electrode slurry was evenly coated on the copper foil of the negative electrode current collector at a ratio of 0.117g/1540.25mm 2 , and the negative electrode sheet was obtained by drying, cold pressing, and slitting.
【电解液的制备】【Preparation of Electrolyte】
在氩气气氛手套箱中(H 2O＜0.1ppm，O 2＜0.1ppm)，作为有机溶剂，将碳酸亚乙酯(EC)/碳酸甲乙酯(EMC)按照体积比3/7混合均匀，加入12.5重量％(基于所述有机溶剂的重量计)LiPF 6溶解于上述有机溶剂中，搅拌均匀，得到电解液。 In an argon atmosphere glove box (H 2 O<0.1ppm, O 2 <0.1ppm), as an organic solvent, mix ethylene carbonate (EC)/ethyl methyl carbonate (EMC) in a volume ratio of 3/7 evenly , add 12.5% by weight (based on the weight of the organic solvent) LiPF 6 to dissolve in the above organic solvent, and stir evenly to obtain an electrolyte solution.
【隔离膜】【Isolation film】
使用市售的厚度为20μm、平均孔径为80nm的PP-PE共聚物微孔薄膜(来自卓高电子科技公司，型号20)。A commercially available PP-PE copolymer microporous film with a thickness of 20 μm and an average pore diameter of 80 nm (from Zhuogao Electronic Technology Company, model 20) was used.
【全电池的制备】【Preparation of full battery】
将上述获得的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入上述电解液并封装，得到全电池(下文也称“全电”)。The above obtained positive electrode sheet, separator, and negative electrode sheet are stacked in order, so that the separator is in the middle of the positive and negative electrodes to play the role of isolation, and the bare cell is obtained by winding. Place the bare cell in the outer package, inject the above electrolyte and package it to obtain a full battery (hereinafter also referred to as "full battery").
【扣式电池的制备】[Preparation of button cell]
将上述制备的双层包覆的磷酸锰锂正极活性材料、PVDF、乙炔黑以90∶5∶5的重量比加入至NMP中，在干燥房中搅拌制成浆料。在铝箔上涂覆上述浆料，干燥、冷压制成正极极片。涂覆量为0.2g/cm 2，压实密度为2.0g/cm 3。 The above-mentioned double-coated lithium manganese phosphate positive electrode active material, PVDF, and acetylene black were added to NMP at a weight ratio of 90:5:5, and stirred in a drying room to form a slurry. The above slurry is coated on the aluminum foil, dried and cold pressed to form a positive electrode sheet. The coating amount was 0.2 g/cm 2 , and the compacted density was 2.0 g/cm 3 .
采用锂片作为负极，采用1mol/L的LiPF 6在体积比1∶1∶1的碳酸亚乙酯(EC)+碳酸二乙酯(DEC)+碳酸二甲酯(DMC)中的溶液作为电解液，与上述制备的正极极片一起在扣电箱中组装成扣式电池(下文也称“扣电”)。 A lithium sheet is used as the negative electrode, and a solution of 1 mol/L LiPF 6 in ethylene carbonate (EC) + diethyl carbonate (DEC) + dimethyl carbonate (DMC) with a volume ratio of 1:1:1 is used as the electrolytic solution. liquid, and assembled into a button battery (hereinafter also referred to as "button battery") in a button box together with the above-mentioned positive pole piece prepared.
实施例1-2至1-6Examples 1-2 to 1-6
在共掺杂磷酸锰锂内核的制备过程中，除不使用二氯化钒和硫酸钴、使用463.4g的碳酸亚铁，1.6g的60％浓度的稀硫酸，1148.9g的磷酸二氢铵和369.0g碳酸锂以外，实施例1-2至1-6中磷酸锰锂内核的制备条件与实施例1-1相同。In the preparation process of the co-doped lithium manganese phosphate inner core, in addition to not using vanadium dichloride and cobalt sulfate, using 463.4g of ferrous carbonate, 1.6g of 60% concentration of dilute sulfuric acid, 1148.9g of ammonium dihydrogen phosphate and Except for 369.0g of lithium carbonate, the preparation conditions of the lithium manganese phosphate core in Examples 1-2 to 1-6 are the same as in Example 1-1.
此外，在焦磷酸铁锂和磷酸铁锂的制备过程以及包覆第一包覆层和第二包覆层的过程中，除所使用的原料按照表1中所示包覆量与实施例1-1对应的包覆量的比值对应调整，以使实施例1-2至1-6中Li 2FeP 2O 7/LiFePO 4的用量分别为12.6g/37.7g、15.7g/47.1g、18.8g/56.5g、22.0/66.0g和25.1g/75.4g，实施例1-2至1-6中蔗糖的用量为37.3g以外，其他条件与实施例1-1相同。 In addition, in the preparation process of lithium iron pyrophosphate and lithium iron phosphate and the process of coating the first cladding layer and the second cladding layer, except that the raw materials used are in accordance with the coating amount shown in Table 1 and Example 1 The ratio of coating amount corresponding to -1 is adjusted accordingly, so that the dosages of Li 2 FeP 2 O 7 /LiFePO 4 in Examples 1-2 to 1-6 are 12.6g/37.7g, 15.7g/47.1g, 18.8 g/56.5g, 22.0/66.0g and 25.1g/75.4g, except that the amount of sucrose used in Examples 1-2 to 1-6 is 37.3g, other conditions are the same as in Example 1-1.
实施例1-7至1-10Examples 1-7 to 1-10
除蔗糖的用量分别为74.6g、149.1g、186.4g和223.7g以使作为第二包覆层的碳层的对应包覆量分别为31.4g、62.9g、78.6g和94.3g以外，实施例1-7至1-10的条件与实施例1-3相同。Except that the consumption of sucrose is respectively 74.6g, 149.1g, 186.4g and 223.7g so that the corresponding coating amounts of the carbon layer as the second coating layer are respectively 31.4g, 62.9g, 78.6g and 94.3g, the embodiment The conditions of 1-7 to 1-10 are the same as in Example 1-3.
实施例1-11至1-14Examples 1-11 to 1-14
除在焦磷酸铁锂和磷酸铁锂的制备过程中按照表1中所示包覆量对应调整各种原料的用量以使Li 2FeP 2O 7/LiFePO 4的用量分别为23.6g/39.3g、31.4g/31.4g、39.3g/23.6g和47.2g/15.7g以外，实施例1-11至1-14的条件与实施例1-7相同。 Except in the preparation process of lithium iron pyrophosphate and lithium iron phosphate, adjust the amount of various raw materials according to the coating amount shown in Table 1 so that the amount of Li 2 FeP 2 O 7 /LiFePO 4 is 23.6g/39.3g respectively , 31.4g/31.4g, 39.3g/23.6g and 47.2g/15.7g, the conditions of Examples 1-11 to 1-14 are the same as those of Example 1-7.
实施例1-15Examples 1-15
除在共掺杂磷酸锰锂内核的制备过程中使用492.80g ZnCO 3代替碳酸亚铁以外，实施例1-15的条件与实施例1-14相同。 Except that 492.80 g of ZnCO was used instead of ferrous carbonate during the preparation of the co-doped lithium manganese phosphate core, the conditions of Examples 1-15 were the same as those of Examples 1-14.
实施例1-16至1-18Examples 1-16 to 1-18
除实施例1-16在共掺杂磷酸锰锂内核的制备过程中使用466.4g的NiCO 3、5.0g的碳酸锌和7.2g的硫酸钛代替碳酸亚铁，实施例1-17 在共掺杂的磷酸锰锂内核的制备过程中使用455.2g的碳酸亚铁和8.5g的二氯化钒，实施例1-18在共掺杂的磷酸锰锂内核的制备过程中使用455.2g的碳酸亚铁、4.9g的二氯化钒和2.5g的碳酸镁以外，实施例1-17至1-19的条件与实施例1-7相同。 Except that in Example 1-16, 466.4g of NiCO 3 , 5.0g of zinc carbonate and 7.2g of titanium sulfate were used instead of ferrous carbonate during the preparation of the co-doped lithium manganese phosphate core, and in Example 1-17 The ferrous carbonate of 455.2g and the vanadium dichloride of 8.5g are used in the preparation process of the lithium manganese phosphate inner core, and the ferrous carbonate of 455.2g is used in the preparation process of the co-doped lithium manganese phosphate inner core in embodiment 1-18 , 4.9g of vanadium dichloride and 2.5g of magnesium carbonate, the conditions of Examples 1-17 to 1-19 are the same as in Example 1-7.
实施例1-19至1-20Examples 1-19 to 1-20
除实施例1-19在共掺杂磷酸锰锂内核的制备过程中使用369.4g的碳酸锂、和以1.05g的60％浓度的稀硝酸代替稀硫酸，实施例1-20在共掺杂的磷酸锰锂内核的制备过程中使用369.7g的碳酸锂、和以0.78g的亚硅酸代替稀硫酸以外，实施例1-19至1-20的条件与实施例1-18相同。Except that embodiment 1-19 uses the lithium carbonate of 369.4g in the preparation process of co-doped lithium manganese phosphate inner core, and replaces dilute sulfuric acid with the dilute nitric acid of 60% concentration of 1.05g, embodiment 1-20 is in co-doped The conditions of Examples 1-19 to 1-20 are the same as those of Example 1-18, except that 369.7 g of lithium carbonate and 0.78 g of silicic acid are used instead of dilute sulfuric acid during the preparation of the lithium manganese phosphate inner core.
实施例1-21至1-22Examples 1-21 to 1-22
除实施例1-21在共掺杂磷酸锰锂内核的制备过程中使用632.0g碳酸锰、463.30g碳酸亚铁、30.5g的二氯化钒、21.0g的碳酸镁和0.78g的亚硅酸；实施例1-22在共掺杂磷酸锰锂内核的制备过程中使用746.9g碳酸锰、289.6g碳酸亚铁、60.9g的二氯化钒、42.1g的碳酸镁和0.78g的亚硅酸以外，实施例1-21至1-22的条件与实施例1-20相同。In addition to Examples 1-21, 632.0g of manganese carbonate, 463.30g of ferrous carbonate, 30.5g of vanadium dichloride, 21.0g of magnesium carbonate and 0.78g of silicate were used in the preparation process of the co-doped lithium manganese phosphate core. ; Embodiment 1-22 uses 746.9g manganese carbonate, 289.6g ferrous carbonate, 60.9g of vanadium dichloride, 42.1g of magnesium carbonate and 0.78g of silicate in the preparation process of co-doped lithium manganese phosphate core Other than that, the conditions of Examples 1-21 to 1-22 are the same as those of Example 1-20.
实施例1-23至1-24Examples 1-23 to 1-24
除实施例1-23在共掺杂磷酸锰锂内核的制备过程中使用804.6g碳酸锰、231.7g碳酸亚铁、1156.2g的磷酸二氢铵、1.2g的硼酸(质量分数99.5％)和370.8g碳酸锂；实施例1-24在共掺杂磷酸锰锂内核的制备过程中使用862.1g碳酸锰、173.8g碳酸亚铁、1155.1g的磷酸二氢铵、1.86g的硼酸(质量分数99.5％)和371.6g碳酸锂以外，实施例1-23至1-24的条件与实施例1-22相同。Except that embodiment 1-23 uses 804.6g manganese carbonate, 231.7g ferrous carbonate, 1156.2g ammonium dihydrogen phosphate, 1.2g boric acid (mass fraction 99.5%) and 370.8 g lithium carbonate; embodiment 1-24 uses 862.1g manganese carbonate, 173.8g ferrous carbonate, 1155.1g ammonium dihydrogen phosphate, boric acid (mass fraction 99.5% of 1.86g) in the preparation process of co-doped lithium manganese phosphate core ) and 371.6g lithium carbonate, the conditions of embodiment 1-23 to 1-24 are identical with embodiment 1-22.
实施例1-25Examples 1-25
除实施例1-25在共掺杂磷酸锰锂内核的制备过程中使用370.1g 碳酸锂、1.56g的亚硅酸和1147.7g的磷酸二氢铵以外，实施例1-25的条件与实施例1-20相同。Except that embodiment 1-25 uses 370.1g of lithium carbonate, 1.56g of silicic acid and 1147.7g of ammonium dihydrogen phosphate in the preparation process of the co-doped lithium manganese phosphate core, the conditions of embodiment 1-25 and embodiment 1-20 are the same.
实施例1-26Examples 1-26
除实施例1-26在共掺杂磷酸锰锂内核的制备过程中使用368.3g碳酸锂、4.9g质量分数为60％的稀硫酸、919.6g碳酸锰、224.8g碳酸亚铁、3.7g二氯化钒、2.5g碳酸镁和1146.8g的磷酸二氢铵以外，实施例1-26的条件与实施例1-20相同。Except that embodiment 1-26 uses 368.3g lithium carbonate, 4.9g mass fraction to be 60% dilute sulfuric acid, 919.6g manganese carbonate, 224.8g ferrous carbonate, 3.7g dichloro Except the ammonium dihydrogen phosphate of vanadium, 2.5g magnesium carbonate and 1146.8g, the condition of embodiment 1-26 is identical with embodiment 1-20.
实施例1-27Examples 1-27
除实施例1-27在共掺杂磷酸锰锂内核的制备过程中使用367.9g碳酸锂、6.5g浓度为60％的稀硫酸和1145.4g的磷酸二氢铵以外，实施例1-27的条件与实施例1-20相同。Except that Example 1-27 uses 367.9g of lithium carbonate, 6.5g concentration of 60% dilute sulfuric acid and 1145.4g of ammonium dihydrogen phosphate in the preparation process of the co-doped lithium manganese phosphate core, the conditions of Example 1-27 Same as Example 1-20.
实施例1-28至1-33Examples 1-28 to 1-33
除实施例1-28至1-33在共掺杂磷酸锰锂内核的制备过程中使用1034.5g碳酸锰、108.9g碳酸亚铁、3.7g二氯化钒和2.5g碳酸镁，碳酸锂的使用量分别为：367.6g、367.2g、366.8g、366.4g、366.0g和332.4g，磷酸二氢铵的使用量分别为：1144.5g、1143.4g、1142.2g、1141.1g、1139.9g和1138.8g，浓度为60％的稀硫酸的使用量分别为：8.2g、9.8g、11.4g、13.1g、14.7g和16.3g以外，实施例1-28至1-33的条件与实施例1-20相同。Except that embodiment 1-28 to 1-33 uses 1034.5g manganese carbonate, 108.9g ferrous carbonate, 3.7g vanadium dichloride and 2.5g magnesium carbonate in the preparation process of co-doped lithium manganese phosphate inner core, the use of lithium carbonate The amounts are: 367.6g, 367.2g, 366.8g, 366.4g, 366.0g, and 332.4g, and the amounts of ammonium dihydrogen phosphate are: 1144.5g, 1143.4g, 1142.2g, 1141.1g, 1139.9g, and 1138.8g, Concentration is that the consumption of the dilute sulfuric acid of 60% is respectively: except 8.2g, 9.8g, 11.4g, 13.1g, 14.7g and 16.3g, the conditions of embodiment 1-28 to 1-33 are identical with embodiment 1-20 .
实施例2-1至2-4Examples 2-1 to 2-4
实施例2-1Example 2-1
除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在粉末烧结步骤中的烧结温度为550℃，烧结时间为1h以控制Li 2FeP 2O 7的结晶度为30％，在磷酸铁锂(LiFePO 4)的制备过程中在包覆烧结步骤中的烧结温度为650℃，烧结时间为2h以控制LiFePO 4的结晶度为30％以外，其他条件与实施例1-1相同。 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the sintering temperature in the powder sintering step is 550°C, and the sintering time is 1h to control the crystallinity of Li 2 FeP 2 O 7 to 30%. In the preparation process of lithium iron phosphate (LiFePO 4 ), the sintering temperature in the coating sintering step is 650° C., and the sintering time is 2 h to control the crystallinity of LiFePO 4 to 30%. Other conditions are the same as in Example 1-1.
实施例2-2Example 2-2
除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在粉末烧结步骤中的烧结温度为550℃，烧结时间为2h以控制Li 2FeP 2O 7的结晶度为50％，在磷酸铁锂(LiFePO 4)的制备过程中在包覆烧结步骤中的烧结温度为650℃，烧结时间为3h以控制LiFePO 4的结晶度为50％以外，其他条件与实施例1-1相同。 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the sintering temperature in the powder sintering step is 550°C, and the sintering time is 2h to control the crystallinity of Li 2 FeP 2 O 7 to 50%. In the preparation process of lithium iron phosphate (LiFePO 4 ), the sintering temperature in the coating sintering step is 650° C., and the sintering time is 3 h to control the crystallinity of LiFePO 4 to 50%. Other conditions are the same as in Example 1-1.
实施例2-3Example 2-3
除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在粉末烧结步骤中的烧结温度为600℃，烧结时间为3h以控制Li 2FeP 2O 7的结晶度为70％，在磷酸铁锂(LiFePO 4)的制备过程中在包覆烧结步骤中的烧结温度为650℃，烧结时间为4h以控制LiFePO 4的结晶度为70％以外，其他条件与实施例1-1相同。 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the sintering temperature in the powder sintering step is 600°C, and the sintering time is 3h to control the crystallinity of Li 2 FeP 2 O 7 to 70%. In the preparation process of lithium iron phosphate (LiFePO 4 ), the sintering temperature in the coating sintering step is 650° C., and the sintering time is 4 hours to control the crystallinity of LiFePO 4 to 70%. Other conditions are the same as in Example 1-1.
实施例2-4Example 2-4
除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在粉末烧结步骤中的烧结温度为650℃，烧结时间为4h以控制Li 2FeP 2O 7的结晶度为100％，在磷酸铁锂(LiFePO 4)的制备过程中在包覆烧结步骤中的烧结温度为700℃，烧结时间为6h以控制LiFePO 4的结晶度为100％以外，其他条件与实施例1-1相同。 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the sintering temperature in the powder sintering step is 650°C, and the sintering time is 4h to control the crystallinity of Li 2 FeP 2 O 7 to 100%. In the preparation process of lithium iron phosphate (LiFePO 4 ), the sintering temperature in the coating sintering step was 700°C, and the sintering time was 6h to control the crystallinity of LiFePO 4 to 100%, other conditions were the same as in Example 1-1.
实施例3-1至3-12Embodiment 3-1 to 3-12
除制备Fe、Co和V共掺杂的草酸锰颗粒的过程中，实施例3-1反应釜内的加热温度/搅拌时间分别为60℃/120分钟；实施例3-2反应釜内的加热温度/搅拌时间分别为70℃/120分钟；实施例3-3反应釜内的加热温度/搅拌时间分别为80℃/120分钟；实施例3-4反应釜内的加热温度/搅拌时间分别为90℃/120分钟；实施例3-5反应釜内的加热温度/搅拌时间分别为100℃/120分钟；实施例3-6反应釜内的加热温度/搅拌时间分别为110℃/120分钟；实施例3-7反应釜内的加热温度/搅拌时间分别为120℃/120分钟；实施例3-8反应釜内的加热温度/搅拌时间分别为130℃/120分钟；实施例3-9反应釜内的加热温度/搅拌时间分别为100℃/60分钟；实施例3-10反应釜内的加热温度 /搅拌时间分别为100℃/90分钟；实施例3-11反应釜内的加热温度/搅拌时间分别为100℃/150分钟；实施例3-12反应釜内的加热温度/搅拌时间分别为100℃/180分钟以外，实施例3-1至3-12的其他条件与实施例1-1相同。In addition to the process of preparing Fe, Co and V co-doped manganese oxalate particles, the heating temperature/stirring time in the reactor of Example 3-1 was respectively 60°C/120 minutes; the heating in the reactor of Example 3-2 Temperature/stirring time is respectively 70 ℃/120 minutes; The heating temperature/stirring time in embodiment 3-3 reactor is respectively 80 ℃/120 minutes; The heating temperature/stirring time in embodiment 3-4 reactor is respectively 90°C/120 minutes; the heating temperature/stirring time in the reactor of Example 3-5 was 100°C/120 minutes respectively; the heating temperature/stirring time in the reactor of Example 3-6 was 110°C/120 minutes respectively; The heating temperature/stirring time in the reactor of embodiment 3-7 is respectively 120 ℃/120 minutes; The heating temperature/stirring time in the reactor of embodiment 3-8 is respectively 130 ℃/120 minutes; Embodiment 3-9 reaction The heating temperature/stirring time in the kettle is respectively 100 DEG C/60 minutes; The heating temperature/stirring time in the embodiment 3-10 reactor is respectively 100 DEG C/90 minutes; The heating temperature/stirring time in the embodiment 3-11 reactor The stirring time is respectively 100°C/150 minutes; the heating temperature/stirring time in the reactor of Example 3-12 is respectively 100°C/180 minutes, other conditions of Examples 3-1 to 3-12 are the same as those of Example 1- 1 is the same.
实施例4-1至4-7Examples 4-1 to 4-7
实施例4-1至4-4：除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在干燥步骤中的干燥温度/干燥时间分别为100℃/4h、150℃/6h、200℃/6h和200℃/6h；在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在烧结步骤中的烧结温度和烧结时间分别为700℃/6h、700℃/6h、700℃/6h和600℃/6h以外，其它条件与实例1-7相同。 Examples 4-1 to 4-4: Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the drying temperature/drying time in the drying step were 100°C/4h, 150°C/6h, 200°C/6h and 200°C/6h; the sintering temperature and sintering time in the sintering step during the preparation of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ) were 700°C/6h, 700°C/6h, 700°C, respectively Except for °C/6h and 600°C/6h, other conditions are the same as in Examples 1-7.
实施例4-5至4-7：除在包覆过程中在干燥步骤中的干燥温度/干燥时间分别为150℃/6h、150℃/6h和150℃/6h；在包覆过程中在烧结步骤中的烧结温度和烧结时间分别为600℃/4h、600℃/6h和800℃/8h以外，其它条件与实例1-12相同。Examples 4-5 to 4-7: Except in the coating process, the drying temperature/drying time in the drying step is 150°C/6h, 150°C/6h and 150°C/6h respectively; Except that the sintering temperature and sintering time in the steps are 600°C/4h, 600°C/6h and 800°C/8h respectively, other conditions are the same as in Examples 1-12.
对比例1Comparative example 1
制备草酸锰：将1149.3g碳酸锰加至反应釜中，并加入5升去离子水和1260.6g二水合草酸(以C 2H 2O 4·2H 2O计，下同)。将反应釜加热至80℃，以600rpm的转速搅拌6小时，直至反应终止(无气泡产生)，得到草酸锰悬浮液，然后过滤所述悬浮液，将滤饼在120℃下烘干，之后进行研磨，得到中值粒径Dv50为100nm的二水草酸锰颗粒。 Preparation of manganese oxalate: 1149.3 g of manganese carbonate was added to the reactor, and 5 liters of deionized water and 1260.6 g of oxalic acid dihydrate (calculated as C 2 H 2 O 4 ·2H 2 O, the same below) were added. The reactor was heated to 80°C, and stirred at a speed of 600rpm for 6 hours until the reaction was terminated (no air bubbles were generated), and a suspension of manganese oxalate was obtained, then the suspension was filtered, and the filter cake was dried at 120°C, and then carried out Grinding to obtain manganese oxalate dihydrate particles with a median particle diameter Dv50 of 100 nm.
制备碳包覆的磷酸锰锂：取1789.6g上述获得的二水草酸锰颗粒、369.4g碳酸锂(以Li 2CO 3计，下同)，1150.1g磷酸二氢铵(以NH 4H 2PO 4计，下同)和31g蔗糖(以C 12H 22O 11计，下同)加入到20升去离子水中，将混合物搅拌10小时使其混合均匀，得到浆料。将所述浆料转移到喷雾干燥设备中进行喷雾干燥造粒，设定干燥温度为250℃，干燥4小时，得到粉料。在氮气(90体积％)+氢气(10体积％)保护气氛中，将上述粉料在700℃下烧结4小时，得到碳包覆的磷酸锰 锂。 Preparation of carbon-coated lithium manganese phosphate: take 1789.6g of manganese oxalate dihydrate particles obtained above, 369.4g of lithium carbonate (calculated as Li 2 CO 3 , the same below), 1150.1g of ammonium dihydrogen phosphate (calculated as NH 4 H 2 PO 4 meter, the same below) and 31 g of sucrose (calculated as C 12 H 22 O 11 , the same below) were added to 20 liters of deionized water, and the mixture was stirred for 10 hours to make it evenly mixed to obtain a slurry. The slurry was transferred to a spray drying device for spray drying and granulation. The drying temperature was set at 250° C. and dried for 4 hours to obtain a powder. In a nitrogen (90 volume %) + hydrogen (10 volume %) protective atmosphere, the above powder was sintered at 700° C. for 4 hours to obtain carbon-coated lithium manganese phosphate.
对比例2Comparative example 2
除使用689.5g的碳酸锰和额外添加463.3g的碳酸亚铁以外，对比例2的其他条件与对比例1相同。Except for using 689.5g of manganese carbonate and additionally adding 463.3g of ferrous carbonate, other conditions of Comparative Example 2 were the same as those of Comparative Example 1.
对比例3Comparative example 3
除使用1148.9g的磷酸二氢铵和369.0g碳酸锂，并额外添加1.6g的60％浓度的稀硫酸以外，对比例3的其他条件与对比例1相同。Except for using 1148.9 g of ammonium dihydrogen phosphate and 369.0 g of lithium carbonate, and additionally adding 1.6 g of 60% concentration of dilute sulfuric acid, other conditions of comparative example 3 were the same as those of comparative example 1.
对比例4Comparative example 4
除使用689.5g的碳酸锰、1148.9g的磷酸二氢铵和369.0g碳酸锂，并额外添加463.3g的碳酸亚铁、1.6g的60％浓度的稀硫酸以外，对比例4的其他条件与对比例1相同。Except using the manganese carbonate of 689.5g, the ammonium dihydrogen phosphate of 1148.9g and 369.0g lithium carbonate, and additionally add the ferrous carbonate of 463.3g, the dilute sulfuric acid of the 60% concentration of 1.6g, other conditions of comparative example 4 and the Scale 1 is the same.
对比例5Comparative example 5
除额外增加以下步骤：制备焦磷酸铁锂粉末：将9.52g碳酸锂、29.9g碳酸亚铁、29.6g磷酸二氢铵和32.5g二水合草酸溶于50ml去离子水中。混合物的pH为5，搅拌2小时使反应混合物充分反应。然后将反应后的溶液升温到80℃并保持该温度4小时，得到包含Li 2FeP 2O 7的悬浊液，将悬浊液进行过滤，用去离子水洗涤，并在120℃下干燥4h，得到粉末。将所述粉末在500℃、氮气气氛下烧结4小时，并自然冷却至室温后进行研磨，控制Li 2FeP 2O 7的结晶度为5％，制备碳包覆的材料时，Li 2FeP 2O 7的用量为62.8g以外，对比例5的其它条件与对比例4相同。 In addition, the following steps were added: Preparation of lithium iron pyrophosphate powder: 9.52g of lithium carbonate, 29.9g of ferrous carbonate, 29.6g of ammonium dihydrogen phosphate and 32.5g of oxalic acid dihydrate were dissolved in 50ml of deionized water. The pH of the mixture was 5, and the reaction mixture was stirred for 2 hours to fully react. Then the temperature of the reacted solution was raised to 80°C and maintained at this temperature for 4 hours to obtain a suspension containing Li 2 FeP 2 O 7 , which was filtered, washed with deionized water, and dried at 120°C for 4 hours , to obtain powder. The powder was sintered at 500°C under a nitrogen atmosphere for 4 hours, and ground after naturally cooling to room temperature. The crystallinity of Li 2 FeP 2 O 7 was controlled to be 5%. When preparing carbon-coated materials, Li 2 FeP 2 Except that the consumption of O 7 is 62.8g, other conditions of Comparative Example 5 are the same as Comparative Example 4.
对比例6Comparative example 6
除额外增加以下步骤：制备磷酸铁锂悬浊液：将14.7g碳酸锂、46.1g碳酸亚铁、45.8g磷酸二氢铵和50.2g二水合草酸溶于500ml去离子水中，然后搅拌6小时使混合物充分反应。然后将反应后的溶液升温到120℃并保持该温度6小时，得到包含LiFePO 4的悬浊液，在 磷酸铁锂(LiFePO 4)的制备过程中在包覆烧结步骤中的烧结温度为600℃，烧结时间为4h以控制LiFePO 4的结晶度为8％以外，制备碳包覆的材料时，LiFePO 4的用量为62.8g以外，对比例6的其它条件与对比例4相同。 In addition to adding the following steps: Preparation of lithium iron phosphate suspension: 14.7g lithium carbonate, 46.1g ferrous carbonate, 45.8g ammonium dihydrogen phosphate and 50.2g dihydrate oxalic acid were dissolved in 500ml deionized water, then stirred for 6 hours to make The mixture reacted well. Then the reacted solution is heated to 120°C and maintained at this temperature for 6 hours to obtain a suspension containing LiFePO 4 , and the sintering temperature in the coating sintering step during the preparation of lithium iron phosphate (LiFePO 4 ) is 600°C , The sintering time is 4h to control the crystallinity of LiFePO 4 to be 8%, when preparing the carbon-coated material, the amount of LiFePO 4 is 62.8g, the other conditions of Comparative Example 6 are the same as Comparative Example 4.
对比例7Comparative example 7
制备焦磷酸铁锂粉末：将2.38g碳酸锂、7.5g碳酸亚铁、7.4g磷酸二氢铵和8.1g二水合草酸溶于50ml去离子水中。混合物的pH为5，搅拌2小时使反应混合物充分反应。然后将反应后的溶液升温到80℃并保持该温度4小时，得到包含Li 2FeP 2O 7的悬浊液，将悬浊液进行过滤，用去离子水洗涤，并在120℃下干燥4h，得到粉末。将所述粉末在500℃、氮气气氛下烧结4小时，并自然冷却至室温后进行研磨，控制Li 2FeP 2O 7的结晶度为5％。 Preparation of lithium iron pyrophosphate powder: 2.38 g of lithium carbonate, 7.5 g of ferrous carbonate, 7.4 g of ammonium dihydrogen phosphate and 8.1 g of oxalic acid dihydrate were dissolved in 50 ml of deionized water. The pH of the mixture was 5, and the reaction mixture was stirred for 2 hours to fully react. Then the temperature of the reacted solution was raised to 80°C and maintained at this temperature for 4 hours to obtain a suspension containing Li 2 FeP 2 O 7 , which was filtered, washed with deionized water, and dried at 120°C for 4 hours , to obtain powder. The powder was sintered at 500° C. under a nitrogen atmosphere for 4 hours, cooled naturally to room temperature, and then ground to control the crystallinity of Li 2 FeP 2 O 7 to 5%.
制备磷酸铁锂悬浊液：将11.1g碳酸锂、34.7g碳酸亚铁、34.4g磷酸二氢铵、37.7g二水合草酸和37.3g蔗糖(以C 12H 22O 11计，下同)溶于1500ml去离子水中，然后搅拌6小时使混合物充分反应。然后将反应后的溶液升温到120℃并保持该温度6小时，得到包含LiFePO 4的悬浊液。 Preparation of lithium iron phosphate suspension: 11.1g of lithium carbonate, 34.7g of ferrous carbonate, 34.4g of ammonium dihydrogen phosphate, 37.7g of oxalic acid dihydrate and 37.3g of sucrose (calculated as C 12 H 22 O 11 , the same below) were dissolved in 1500 ml of deionized water, then stirred for 6 hours to fully react the mixture. The reacted solution was then warmed up to 120 °C and kept at this temperature for 6 hours to obtain a suspension containing LiFePO4 .
将得到的焦磷酸铁锂粉末15.7g，加入上述磷酸铁锂(LiFePO 4)和蔗糖悬浊液中，制备过程中在包覆烧结步骤中的烧结温度为600℃，烧结时间为4h以控制LiFePO 4的结晶度为8％以外，对比例7的其它条件与对比例4相同，得到非晶态焦磷酸铁锂、非晶态磷酸铁锂、碳包覆的正极活性材料。 Add 15.7 g of the obtained lithium iron phosphate powder to the above-mentioned lithium iron phosphate (LiFePO 4 ) and sucrose suspension. During the preparation process, the sintering temperature in the coating sintering step is 600 ° C, and the sintering time is 4 hours to control the LiFePO 4 Except that the crystallinity of 4 was 8%, the other conditions of Comparative Example 7 were the same as those of Comparative Example 4, and amorphous lithium iron pyrophosphate, amorphous lithium iron phosphate, and carbon-coated positive electrode active materials were obtained.
对比例8-11Comparative example 8-11
除在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在干燥步骤中的干燥温度/干燥时间在对比例8-10中分别为80℃/3h、80℃/3h、80℃/3h；在焦磷酸铁锂(Li 2FeP 2O 7)的制备过程中在烧结步骤中的烧结温度和烧结时间在对比例8-10中分别为400℃/3h、400℃/3h、350℃/2h，对比例11在磷酸铁锂(LiFePO 4)的制备过程中在干燥步骤中的干燥温 度/干燥时间为80℃/3h；以及在对比例8-11中Li 2FeP 2O 7/LiFePO 4的用量分别为47.2g/15.7g、15.7g/47.2g、62.8g/0g、0g/62.8g以外，其他条件与实施例1-7相同。 Except in the preparation process of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), the drying temperature/drying time in the drying step was 80°C/3h, 80°C/3h, 80°C/ 3h; the sintering temperature and sintering time in the sintering step during the preparation of lithium iron pyrophosphate (Li 2 FeP 2 O 7 ) were 400°C/3h, 400°C/3h, and 350°C in Comparative Examples 8-10, respectively /2h, the drying temperature/drying time in the drying step during the preparation of lithium iron phosphate (LiFePO 4 ) in Comparative Example 11 was 80°C/3h; and Li 2 FeP 2 O 7 /LiFePO in Comparative Examples 8-11 Except that the dosage of 4 is 47.2g/15.7g, 15.7g/47.2g, 62.8g/0g, 0g/62.8g respectively, other conditions are the same as in Examples 1-7.
上述实施例和对比例的【正极极片的制备】、【负极极片的制备】、【电解液的制备】、【隔离膜】和【电池的制备】均与实施例1-1的工艺相同。[Preparation of Positive Electrode], [Preparation of Negative Electrode], [Preparation of Electrolyte], [Separator] and [Preparation of Battery] in the above examples and comparative examples are all the same as those in Example 1-1. .
【相关参数测试】【Related parameter test】
1.扣式电池初始克容量测试：1. Initial gram capacity test of button battery:
在2.5～4.3V下，将上述制得的扣式电池按照0.1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA，静置5min，然后按照0.1C放电至2.0V，此时的放电容量为初始克容量，记为D0。At 2.5-4.3V, charge the button cell prepared above to 4.3V at 0.1C, then charge at a constant voltage at 4.3V until the current is less than or equal to 0.05mA, let it stand for 5min, and then discharge at 0.1C to 2.0V , the discharge capacity at this time is the initial gram capacity, denoted as D0.
2.扣电平均放电电压(V)测试：2. Test the average discharge voltage (V) of the button:
将上述制得的扣式电池在25℃恒温环境下，静置5min，按照0.1C放电至2.5V，静置5min，按照0.1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA，静置5min；然后按照0.1C放电至2.5V，此时的放电容量为初始克容量，记为D0，放电能量为初始能量，记为E0，扣电平均放电电压V即为E0/D0。Put the button battery prepared above at a constant temperature of 25°C, let it stand for 5 minutes, discharge it at 0.1C to 2.5V, let it stand for 5 minutes, charge it at 0.1C to 4.3V, and then charge it at a constant voltage at 4.3V until the current is less than Equal to 0.05mA, let stand for 5 minutes; then discharge to 2.5V according to 0.1C, the discharge capacity at this time is the initial gram capacity, denoted as D0, the discharge energy is the initial energy, denoted as E0, and the average discharge voltage V after charging is E0 /D0.
3.全电池60℃胀气测试：3. Full battery 60°C flatulence test:
在60℃下，存储100％充电状态(SOC)的上述制得的全电池。在存储前后及过程中测量电芯的开路电压(OCV)和交流内阻(IMP)以监控SOC，并测量电芯的体积。其中在每存储48h后取出全电池，静置1h后测试开路电压(OCV)、内阻(IMP)，并在冷却至室温后用排水法测量电芯体积。排水法即先用表盘数据自动进行单位转换的天平单独测量电芯的重力F 1，然后将电芯完全置于去离子水(密度已知为1g/cm 3)中，测量此时的电芯的重力F 2，电芯受到的浮力F 浮即为F 1-F 2，然后根据阿基米德原理F 浮＝ρ×g×V 排，计算得到电芯 体积V＝(F 1-F 2)/(ρ×g)。 The above-fabricated full cells were stored at 60°C at 100% state of charge (SOC). The open circuit voltage (OCV) and AC internal resistance (IMP) of the cell are measured before, after and during storage to monitor the SOC, and the volume of the cell is measured. Among them, the full battery was taken out after every 48 hours of storage, and the open circuit voltage (OCV) and internal resistance (IMP) were tested after standing for 1 hour, and the cell volume was measured by the drainage method after cooling to room temperature. The drainage method is to first measure the gravity F 1 of the cell with a balance that automatically performs unit conversion on the dial data, and then place the cell completely in deionized water (with a known density of 1g/cm 3 ) to measure the cell at this time gravity F 2 , the buoyancy force F float on the cell is F 1 -F 2 , and then according to Archimedes’ principle F float = ρ×g×V row , the cell volume V=(F 1 -F 2 )/(ρ×g).
由OCV、IMP测试结果来看，本实验过程中直至存储结束，全部实施例的电池始终保持99％以上的SOC。According to the test results of OCV and IMP, the batteries of all the examples kept the SOC above 99% during the experiment until the end of storage.
存储30天后，测量电芯体积，并计算相对于存储前的电芯体积，存储后的电芯体积增加的百分比。After 30 days of storage, measure the cell volume and calculate the percentage increase in cell volume after storage relative to the cell volume before storage.
另外，测量电芯残余容量。在2.5～4.3V下，将全电池按照1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA。静置5min，记录此时的充电容量为电芯残余容量。In addition, measure the residual capacity of the battery. At 2.5-4.3V, charge the full battery to 4.3V at 1C, and then charge at a constant voltage at 4.3V until the current is less than or equal to 0.05mA. Stand still for 5 minutes, and record the charging capacity at this time as the remaining capacity of the battery cell.
4.全电池45℃下循环性能测试：4. Cycle performance test of full battery at 45°C:
在45℃的恒温环境下，在2.5～4.3V下，将上述制得的全电池按照1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA。静置5min，然后按照1C放电至2.5V，记录此时的放电容量为D0。重复前述充放电循环，直至放电容量降低到D0的80％。记录此时电池经过的循环圈数。In a constant temperature environment of 45°C, at 2.5-4.3V, the full battery prepared above was charged to 4.3V at 1C, and then charged at a constant voltage at 4.3V until the current was less than or equal to 0.05mA. Let stand for 5 minutes, then discharge to 2.5V according to 1C, and record the discharge capacity at this time as D0. Repeat the above charge and discharge cycles until the discharge capacity is reduced to 80% of D0. Record the number of cycles the battery has gone through at this time.
5.晶格变化率测试：5. Lattice change rate test:
在25℃恒温环境下，将上述制得的正极活性材料样品置于XRD(型号为Bruker D8 Discover)中，采用1°/min对样品进行测试，并对测试数据进行整理分析，参照标准PDF卡片，计算出此时的晶格常数a0、b0、c0和v0(a0、b0和c0表示晶胞各个方面上的长度大小，v0表示晶胞体积，可通过XRD精修结果直接获取)。In a constant temperature environment of 25°C, put the positive electrode active material sample prepared above in an XRD (model Bruker D8 Discover), test the sample at 1°/min, and organize and analyze the test data, refer to the standard PDF card , Calculate the lattice constants a0, b0, c0 and v0 at this time (a0, b0 and c0 represent the length of the unit cell in all aspects, and v0 represents the volume of the unit cell, which can be directly obtained through XRD refinement results).
采用上述扣电制备方法，将所述正极活性材料样品制备成扣电，并对上述扣电以0.05C小倍率进行充电，直至电流减小至0.01C。然后将扣电中的正极极片取出，并置于碳酸二甲酯(DMC)中浸泡8小时。然后烘干，刮粉，并筛选出其中粒径小于500nm的颗粒。取样并按照与上述测试新鲜样品同样的方式计算出其晶胞体积v1，将(v0-v1)/v0×100％作为其完全脱嵌锂前后的晶格变化率(晶胞体积变化率)示于表中。The anode active material sample was prepared as a button charge using the above button charge preparation method, and the above button charge was charged at a small rate of 0.05C until the current was reduced to 0.01C. Then take out the positive pole piece in the button battery, and soak in dimethyl carbonate (DMC) for 8 hours. Then dry, scrape the powder, and screen out the particles whose particle size is less than 500nm. Take a sample and calculate its unit cell volume v1 in the same way as the above-mentioned test fresh sample, and use (v0-v1)/v0×100% as the lattice change rate (unit cell volume change rate) before and after it completely deintercalates lithium. in the table.
6.Li/Mn反位缺陷浓度测试：6. Li/Mn antisite defect concentration test:
将“晶格变化率测量方法”中测试的XRD结果与标准晶体的PDF(Powder Diffraction File)卡片对比，得出Li/Mn反位缺陷浓度。具体而言，将“晶格变化率测量方法”中测试的XRD结果导入通用结构分析系统(GSAS)软件中，自动获得精修结果，其中包含了不同原子的占位情况，通过读取精修结果获得Li/Mn反位缺陷浓度。Comparing the XRD results tested in the "Lattice Change Rate Measurement Method" with the standard crystal PDF (Powder Diffraction File) card, the Li/Mn antisite defect concentration is obtained. Specifically, import the XRD results tested in the "Measurement Method of Lattice Change Rate" into the General Structural Analysis System (GSAS) software, and automatically obtain the refined results, which include the occupancy of different atoms. By reading the refined As a result, the Li/Mn antisite defect concentration is obtained.
7.过渡金属溶出测试：7. Transition metal dissolution test:
将45℃下循环至容量衰减至80％后的全电池采用0.1C倍率进行放电至截止电压2.0V。然后将电池拆开，取出负极极片，在负极极片上随机取30个单位面积(1540.25mm 2)的圆片，用Agilent ICP-OES730测试电感耦合等离子体发射光谱(ICP)。根据ICP结果计算其中Fe(如果正极活性材料的Mn位掺杂有Fe的话)和Mn的量，从而计算循环后Mn(以及Mn位掺杂的Fe)的溶出量。测试标准依据EPA-6010D-2014。 The full battery was discharged to a cut-off voltage of 2.0V at a rate of 0.1C after being cycled at 45°C until the capacity decayed to 80%. Then the battery was disassembled, and the negative pole piece was taken out. On the negative pole piece, 30 discs with a unit area (1540.25mm 2 ) were randomly selected, and the inductively coupled plasma emission spectrum (ICP) was tested with Agilent ICP-OES730. According to the ICP results, the amounts of Fe (if the Mn site of the positive electrode active material is doped with Fe) and Mn are calculated, so as to calculate the dissolution amount of Mn (and Fe doped at the Mn site) after cycling. The test standard is based on EPA-6010D-2014.
8.表面氧价态测试：8. Surface oxygen valence test:
取5g上述制得的正极活性材料样品按照上述扣电制备方法制备成扣电。对扣电采用0.05C小倍率进行充电，直至电流减小至0.01C。然后将扣电中的正极极片取出，并置于碳酸二甲酯(DMC)中浸泡8小时。然后烘干，刮粉，并筛选出其中粒径小于500nm的颗粒。将所得颗粒用电子能量损失谱(EELS，所用仪器型号为Talos F200S)进行测量，获取能量损失近边结构(ELNES)，其反映元素的态密度和能级分布情况。根据态密度和能级分布，通过对价带态密度数据进行积分，算出占据的电子数，从而推算出充电后的表面氧的价态。Take 5 g of the positive electrode active material sample prepared above to prepare a button electrode according to the above button electrode preparation method. Charge the button with a small rate of 0.05C until the current decreases to 0.01C. Then take out the positive pole piece in the button battery, and soak in dimethyl carbonate (DMC) for 8 hours. Then dry, scrape the powder, and screen out the particles whose particle size is less than 500nm. The obtained particles were measured by electron energy loss spectroscopy (EELS, the instrument model used was Talos F200S), and the energy loss near-edge structure (ELNES) was obtained, which reflected the density of states and energy level distribution of the elements. According to the density of states and energy level distribution, the number of occupied electrons is calculated by integrating the data of the valence band density of states, so as to calculate the valence state of the charged surface oxygen.
9.压实密度测量：9. Compaction density measurement:
取5g的上述制得的正极活性材料粉末放于压实专用模具(美国CARVER模具，型号13mm)中，然后将模具放在压实密度仪器上。施加3T的压力，在设备上读出压力下粉末的厚度(卸压后的厚度， 用于测试的容器的面积为1540.25mm 2)，通过ρ＝m/v，计算出压实密度。 Take 5g of the positive electrode active material powder prepared above and put it in a special compacting mold (CARVER mold in the United States, model 13mm), and then put the mold on a compaction density instrument. Apply a pressure of 3T, read the thickness of the powder under pressure on the device (thickness after pressure relief, the area of the container used for the test is 1540.25mm 2 ), and calculate the compacted density by ρ=m/v.
10.X射线衍射法测试焦磷酸盐和磷酸盐的结晶度10. X-ray diffraction method to test the crystallinity of pyrophosphate and phosphate
取5g上述制得的正极活性材料粉末，通过X射线测得总散射强度，它是整个空间物质的散射强度之和，只与初级射线的强度、化学结构、参加衍射的总电子数即质量多少有关，而与样品的序态无关；然后从衍射图上将结晶散射和非结晶散射分开，结晶度即是结晶部分散射与散射总强度之比。Take 5g of the positive electrode active material powder prepared above, and measure the total scattering intensity by X-rays, which is the sum of the scattering intensity of the entire space material, and is only related to the intensity of the primary ray, the chemical structure, and the total number of electrons participating in the diffraction, that is, the mass. It is related, but not related to the order state of the sample; then the crystalline scattering and the non-crystalline scattering are separated from the diffraction pattern, and the degree of crystallinity is the ratio of the crystalline partial scattering to the total scattering intensity.
11.晶面间距和夹角11. Interplane spacing and included angle
取1g上述制得的各正极活性材料粉末于50mL的试管中，并在试管中注入10mL质量分数为75％的酒精，然后进行充分搅拌分散30分钟，然后用干净的一次性塑料吸管取适量上述溶液滴加在300目铜网上，此时，部分粉末将在铜网上残留，将铜网连带样品转移至TEM(Talos F200s G2)样品腔中进行测试，得到TEM测试原始图片，保存原始图片格式(xx.dm3)。Take 1g of each positive electrode active material powder prepared above in a 50mL test tube, and inject 10mL of alcohol with a mass fraction of 75% into the test tube, then fully stir and disperse for 30 minutes, and then use a clean disposable plastic straw to take an appropriate amount of the above The solution is dripped on the 300-mesh copper grid. At this time, part of the powder will remain on the copper grid. Transfer the copper grid and the sample to the TEM (Talos F200s G2) sample chamber for testing, and obtain the original picture of the TEM test. Save the original picture format ( xx.dm3).
将上述TEM测试所得原始图片在DigitalMicrograph软件中打开，并进行傅里叶变换(点击操作后由软件自动完成)得到衍射花样，量取衍射花样中衍射光斑到中心位置的距离，即可得到晶面间距，夹角根据布拉格方程进行计算得到。Open the original picture obtained from the above TEM test in DigitalMicrograph software, and perform Fourier transform (automatically completed by the software after clicking the operation) to obtain a diffraction pattern, and measure the distance from the diffraction spot to the center position in the diffraction pattern to obtain the crystal plane The spacing and included angle are calculated according to the Bragg equation.
Figure PCTCN2021130350-appb-000001
Figure PCTCN2021130350-appb-000001
Figure PCTCN2021130350-appb-000002
Figure PCTCN2021130350-appb-000002
Figure PCTCN2021130350-appb-000003
Figure PCTCN2021130350-appb-000003
Figure PCTCN2021130350-appb-000004
Figure PCTCN2021130350-appb-000004
Figure PCTCN2021130350-appb-000005
Figure PCTCN2021130350-appb-000005
综合实施例1-1至1-33以及对比例1-4可知，第一包覆层的存在有利于降低所得材料的Li/Mn反位缺陷浓度和循环后Fe和Mn溶出量，提高电池的扣电克容量，并改善电池的安全性能和循环性能。当在Mn位和磷位分别掺杂其他元素时，可显著降低所得材料的晶格变化率、反位缺陷浓度和Fe和Mn溶出量，提高电池的克容量，并改善电池的安全性能和循环性能。Based on Examples 1-1 to 1-33 and Comparative Example 1-4, it can be known that the existence of the first cladding layer is beneficial to reduce the Li/Mn antisite defect concentration of the obtained material and the amount of Fe and Mn dissolved after cycling, and improve the battery performance. Reduce battery capacity and improve battery safety and cycle performance. When other elements are doped on the Mn site and the phosphorus site respectively, the lattice change rate, antisite defect concentration and Fe and Mn dissolution amount of the obtained material can be significantly reduced, the gram capacity of the battery can be increased, and the safety performance and cycle of the battery can be improved. performance.
综合实施例1-1至1-6可知，随着第一包覆层的量从3.2％增加至6.4％，所得材料的Li/Mn反位缺陷浓度逐渐下降，循环后Fe和Mn溶出量逐渐下降，对应电池的安全性能和45℃下的循环性能也得到改善，但扣电克容量略有下降。可选地，当第一包覆层的总量为4-5.6重量％时，对应电池的综合性能最佳。Combining Examples 1-1 to 1-6, it can be seen that as the amount of the first cladding layer increases from 3.2% to 6.4%, the Li/Mn antisite defect concentration of the obtained material gradually decreases, and the dissolution amount of Fe and Mn gradually decreases after cycling. Correspondingly, the safety performance of the battery and the cycle performance at 45°C are also improved, but the deduction capacity is slightly reduced. Optionally, when the total amount of the first coating layer is 4-5.6% by weight, the overall performance of the corresponding battery is the best.
综合实施例1-3以及实施例1-7至1-10可知，随着第二包覆层的量从1％增加至6％，所得材料的Li/Mn反位缺陷浓度逐渐下降，循环后Fe和Mn溶出量逐渐下降，对应电池的安全性能和45℃下的循环性能也得到改善，但扣电克容量却略有下降。可选地，当第二包覆层的总量为3-5重量％时，对应电池的综合性能最佳。Combining Examples 1-3 and Examples 1-7 to 1-10, it can be seen that as the amount of the second cladding layer increases from 1% to 6%, the Li/Mn antisite defect concentration of the obtained material gradually decreases, and after cycling The dissolution of Fe and Mn decreased gradually, and the safety performance of the corresponding battery and the cycle performance at 45°C were also improved, but the buckle capacity decreased slightly. Optionally, when the total amount of the second coating layer is 3-5% by weight, the overall performance of the corresponding battery is the best.
综合实施例1-11至1-15以及对比例5-6可知，当第一包覆层中同时存在Li 2FeP 2O 7和LiFePO 4、特别是Li 2FeP 2O 7和LiFePO 4的重量比为1∶3至3∶1，并且尤其是1∶3至1∶1时，对电池性能的改善更加明显。 Combining Examples 1-11 to 1-15 and Comparative Examples 5-6, it can be seen that when Li 2 FeP 2 O 7 and LiFePO 4 exist in the first cladding layer, especially the weight of Li 2 FeP 2 O 7 and LiFePO 4 When the ratio is 1:3 to 3:1, and especially 1:3 to 1:1, the improvement of battery performance is more obvious.
Figure PCTCN2021130350-appb-000006
Figure PCTCN2021130350-appb-000006
Figure PCTCN2021130350-appb-000007
Figure PCTCN2021130350-appb-000007
Figure PCTCN2021130350-appb-000008
Figure PCTCN2021130350-appb-000008
Figure PCTCN2021130350-appb-000009
Figure PCTCN2021130350-appb-000009

Claims (27)

  1. 一种具有核-壳结构的正极活性材料，其包括内核及包覆所述内核的壳，A positive electrode active material with a core-shell structure, comprising an inner core and a shell covering the inner core,
    所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100～0.100，y＝0.001～0.500，z＝0.001～0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； The inner core includes Li 1+x Mn 1-y A y P 1-z R z O 4 , wherein x=-0.100～0.100, y=0.001～0.500, z=0.001～0.100, and the A is selected from Zn, One or more of Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, may be Fe, Ti, V, One or more of Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
    所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，the shell includes a first cladding layer covering the inner core and a second cladding layer covering the first cladding layer,
    其中，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Wherein, the first cladding layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein the M and X are each independently selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, One or more of Ag, Zr, Nb or Al;
    所述第二包覆层包含碳。The second cladding layer includes carbon.
  2. 根据权利要求1所述的正极活性材料，其中，The positive electrode active material according to claim 1, wherein,
    所述第一包覆层的磷酸盐的晶面间距为0.345-0.358nm，晶向(111)的夹角为24.25°-26.45°；所述第一包覆层的焦磷酸盐的晶面间距为0.293-0.326nm，晶向(111)的夹角为26.41°-32.57°。The interplanar spacing of the phosphate in the first cladding layer is 0.345-0.358nm, and the included angle of the crystal direction (111) is 24.25°-26.45°; the interplanar spacing of the pyrophosphate in the first cladding layer 0.293-0.326nm, and the included angle of the crystal direction (111) is 26.41°-32.57°.
  3. 根据权利要求1或2所述的正极活性材料，其中，The positive electrode active material according to claim 1 or 2, wherein,
    在所述内核中，y与1-y的比值为1：10至10：1，可选为1：4至1：1。In said kernel, the ratio of y to 1-y is 1:10 to 10:1, optionally 1:4 to 1:1.
  4. 根据权利要求1-3中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-3, wherein,
    在所述内核中，z与1-z的比值为1：9至1：999，可选为1：499至1：249。In said kernel, the ratio of z to 1-z is 1:9 to 1:999, optionally 1:499 to 1:249.
  5. 根据权利要求1-4中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-4, wherein,
    所述第一包覆层的包覆量大于0重量％且小于等于7重量％，可选为4-5.6重量％，基于所述内核的重量计。The coating amount of the first coating layer is greater than 0% by weight and less than or equal to 7% by weight, optionally 4-5.6% by weight, based on the weight of the inner core.
  6. 根据权利要求1-5中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-5, wherein,
    所述第一包覆层中焦磷酸盐和磷酸盐的重量比为1:3至3:1，可 选为1:3至1:1。The weight ratio of pyrophosphate and phosphate in the first coating layer is 1:3 to 3:1, optionally 1:3 to 1:1.
  7. 根据权利要求1-6中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-6, wherein,
    所述焦磷酸盐和磷酸盐的结晶度各自独立地为10％至100％，可选为50％至100％。The crystallinity of the pyrophosphate and the phosphate is independently 10% to 100%, optionally 50% to 100%.
  8. 根据权利要求1-7中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-7, wherein,
    所述第二包覆层的包覆量为大于0重量％且小于等于6重量％，可选为3-5重量％，基于所述内核的重量计。The coating amount of the second coating layer is greater than 0% by weight and less than or equal to 6% by weight, optionally 3-5% by weight, based on the weight of the inner core.
  9. 根据权利要求1-8中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-8, wherein,
    所述A选自Fe、Ti、V、Ni、Co和Mg中的至少两种。The A is at least two selected from Fe, Ti, V, Ni, Co and Mg.
  10. 根据权利要求1-9中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-9, wherein,
    所述正极活性材料的Li/Mn反位缺陷浓度为4％以下，可选为2％以下。The Li/Mn antisite defect concentration of the positive electrode active material is less than 4%, optionally less than 2%.
  11. 根据权利要求1-10中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-10, wherein,
    所述正极活性材料的晶格变化率为6％以下，可选为4％以下。The lattice change rate of the positive electrode active material is less than 6%, optionally less than 4%.
  12. 根据权利要求1-11中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-11, wherein,
    所述正极活性材料的表面氧价态为-1.88以下，可选地为-1.98～-1.88。The surface oxygen valence state of the positive electrode active material is less than -1.88, optionally -1.98˜-1.88.
  13. 根据权利要求1-12中任一项所述的正极活性材料，其中，The positive electrode active material according to any one of claims 1-12, wherein,
    所述正极活性材料在3吨下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。 The compacted density of the positive electrode active material at 3 tons is above 2.0 g/cm 3 , optionally above 2.2 g/cm 3 .
  14. 一种正极活性材料的制备方法，包括以下步骤：A preparation method of positive electrode active material, comprising the following steps:
    提供内核材料的步骤：所述内核包括Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种； Step of providing core material: the core comprises Li 1+x Mn 1-y A y P 1-z R z O 4 , where x=-0.100-0.100, y=0.001-0.500, z=0.001-0.100, the Said A is selected from one or more of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and may be One or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from one or more of B, Si, N and S;
    包覆步骤：提供MP 2O 7粉末和包含碳的源的XPO 4悬浊液，将所述内核材料、MP 2O 7粉末加入到包含碳的源的XPO 4悬浊液中并混合，经烧结获得正极活性材料，其中所述M和X各自独立地选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种； Coating step: provide MP 2 O 7 powder and XPO 4 suspension containing carbon source, add the core material, MP 2 O 7 powder into XPO 4 suspension containing carbon source and mix, Sintering to obtain a positive electrode active material, wherein the M and X are each independently selected from one or more of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb or Al;
    其中，所述正极活性材料具有核-壳结构，其包括内核及包覆所述内核的壳，所述壳包括包覆所述内核的第一包覆层以及包覆所述第一包覆层的第二包覆层，所述第一包覆层包括焦磷酸盐MP 2O 7和磷酸盐XPO 4，所述第二包覆层包含碳。 Wherein, the positive electrode active material has a core-shell structure, which includes an inner core and a shell covering the inner core, and the shell includes a first cladding layer covering the inner core and a shell covering the first cladding layer. The second coating layer, the first coating layer includes pyrophosphate MP 2 O 7 and phosphate XPO 4 , and the second coating layer includes carbon.
  15. 根据权利要求14所述的正极活性材料的制备方法，所述提供内核材料的步骤包括以下步骤：The preparation method of positive electrode active material according to claim 14, said step of providing inner core material comprises the following steps:
    步骤(1)：将锰的源、元素A的源和酸在容器中混合并搅拌，得到掺杂有元素A的锰盐颗粒；Step (1): mixing and stirring a source of manganese, a source of element A, and an acid in a container to obtain manganese salt particles doped with element A;
    步骤(2)：将所述掺杂有元素A的锰盐颗粒与锂的源、磷的源和元素R的源在溶剂中混合并得到浆料，在惰性气体气氛保护下烧结后得到掺杂有元素A和元素R的磷酸锰锂，其中，所述掺杂有元素A和元素R的磷酸锰锂为Li 1+xMn 1-yA yP 1-zR zO 4，其中x＝-0.100-0.100，y＝0.001-0.500，z＝0.001-0.100，所述A选自Zn、Al、Na、K、Mg、Mo、W、Ti、V、Zr、Fe、Ni、Co、Ga、Sn、Sb、Nb和Ge中的一种或多种，可选为Fe、Ti、V、Ni、Co和Mg中的一种或多种，所述R选自B、Si、N和S中的一种或多种。 Step (2): Mix the manganese salt particles doped with element A with a source of lithium, a source of phosphorus and a source of element R in a solvent to obtain a slurry, which is sintered under the protection of an inert gas atmosphere to obtain a doped Lithium manganese phosphate with element A and element R, wherein the lithium manganese phosphate doped with element A and element R is Li 1+x Mn 1-y A y P 1-z R z O 4 , where x= -0.100-0.100, y=0.001-0.500, z=0.001-0.100, said A is selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, One or more of Sn, Sb, Nb and Ge, optionally one or more of Fe, Ti, V, Ni, Co and Mg, the R is selected from B, Si, N and S one or more of .
  16. 根据权利要求15所述的方法，其中，The method of claim 15, wherein,
    所述步骤(1)在20-120℃，可选为25-80℃的温度下进行；和/或，The step (1) is carried out at a temperature of 20-120°C, optionally 25-80°C; and/or,
    所述步骤(1)中所述搅拌在500-700rpm下进行60-420分钟，可选地为120-360分钟。The stirring in the step (1) is carried out at 500-700 rpm for 60-420 minutes, optionally for 120-360 minutes.
  17. 根据权利要求15～16中任一项所述的方法，其中，The method according to any one of claims 15-16, wherein,
    所述元素A的源选自元素A的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物中的一种或多种；和/或，所述元素R的源选自元素R的单质、硫酸盐、卤化物、硝酸盐、有机酸盐、氧化物或氢氧化物以及元素R的无机酸中的一种或多种。The source of the element A is selected from one or more of element A, sulfate, halide, nitrate, organic acid salt, oxide or hydroxide; and/or, the source of the element R One or more selected from elemental R elements, sulfates, halides, nitrates, organic acid salts, oxides or hydroxides, and inorganic acids of element R.
  18. 根据权利要求14～17中任一项所述的方法，其中，The method according to any one of claims 14-17, wherein,
    所述MP 2O 7粉末通过以下方法制备： The MP 2 O 7 powder is prepared by the following method:
    将元素M的源和磷的源添加到溶剂中，得到混合物，调节混合物的pH为4-6，搅拌并充分反应，然后经干燥、烧结获得，其中M 选自Li、Fe、Ni、Mg、Co、Cu、Zn、Ti、Ag、Zr、Nb或Al中的一种或多种。Add the source of element M and the source of phosphorus to the solvent to obtain a mixture, adjust the pH of the mixture to 4-6, stir and fully react, then dry and sinter to obtain, wherein M is selected from Li, Fe, Ni, Mg, One or more of Co, Cu, Zn, Ti, Ag, Zr, Nb or Al.
  19. 根据权利要求18所述的方法，其中，The method of claim 18, wherein,
    所述干燥步骤为在100-300℃、可选150-200℃下干燥4-8h。The drying step is drying at 100-300° C., optionally 150-200° C., for 4-8 hours.
  20. 根据权利要求18～19中任一项所述的方法，其中，The method according to any one of claims 18-19, wherein,
    所述烧结步骤为在500-800℃、可选650-800℃下，在惰性气体气氛下烧结4-10h。The sintering step is sintering at 500-800° C., optionally 650-800° C., in an inert gas atmosphere for 4-10 hours.
  21. 根据权利要求14～20中任一项所述的方法，其中，The method according to any one of claims 14-20, wherein,
    所述包覆步骤中的烧结温度为500-800℃，烧结时间为4-10h。The sintering temperature in the cladding step is 500-800° C., and the sintering time is 4-10 hours.
  22. 一种正极极片，其包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括权利要求1-13中任一项所述的正极活性材料或通过权利要求14-21中任一项所述的方法制备的正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。A positive electrode sheet, comprising a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer comprising the positive electrode active material described in any one of claims 1-13 or by claim The positive electrode active material prepared by the method described in any one of 14-21, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
  23. 根据权利要求22所述的正极极片，其中所述正极活性材料在所述正极膜层中的含量为90-99.5重量％，基于所述正极膜层的总重量计。The positive electrode sheet according to claim 22, wherein the content of the positive electrode active material in the positive electrode film layer is 90-99.5% by weight, based on the total weight of the positive electrode film layer.
  24. 一种二次电池，包括根据权利要求1-13中任一项所述的正极活性材料或通过权利要求14-21中任一项所述的方法制备的正极活性材料或者权利要求22或23所述的正极极片。A secondary battery, comprising the positive electrode active material according to any one of claims 1-13 or the positive electrode active material prepared by the method according to any one of claims 14-21 or the positive electrode active material according to claim 22 or 23 The positive electrode sheet described above.
  25. 一种电池模块，其特征在于，包括权利要求24所述的二次电池。A battery module comprising the secondary battery according to claim 24.
  26. 一种电池包，其特征在于，包括权利要求25所述的电池模块。A battery pack, characterized by comprising the battery module according to claim 25.
  27. 一种用电装置，其特征在于，包括选自权利要求24所述的二次电池、权利要求25所述的电池模块或权利要求26所述的电池包中的至少一种。An electrical device, characterized by comprising at least one selected from the secondary battery of claim 24, the battery module of claim 25, or the battery pack of claim 26.
PCT/CN2021/130350 2021-10-22 2021-11-12 Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack, and electric device WO2023082182A1 (en)

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CN202280013384.3A CN116964781A (en) 2021-10-22 2022-10-21 Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack, and electricity device
PCT/CN2022/126829 WO2023066393A1 (en) 2021-10-22 2022-10-21 Positive electrode active material, positive electrode sheet, secondary battery, battery module, battery pack, and electric device
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AU2022371736A AU2022371736A1 (en) 2021-10-22 2022-10-21 Positive electrode active material and preparation method therefor, positive electrode pole piece, secondary battery, battery module, battery pack, and power-consuming device
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KR1020237024611A KR20230122108A (en) 2021-10-22 2022-10-21 Positive electrode active material and manufacturing method, positive electrode plate, secondary battery, battery module, battery pack and electric device
KR1020247007998A KR20240046889A (en) 2021-10-22 2022-10-21 Cathode active materials, cathode plates, secondary batteries, battery modules, battery packs, and electrical devices
KR1020247008222A KR20240048003A (en) 2021-10-22 2022-10-21 Cathode active material, cathode plate, secondary battery, battery module, battery pack, and electrical device
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