WO2018171144A1 - 正极材料及其制备方法 - Google Patents

正极材料及其制备方法 Download PDF

Info

Publication number
WO2018171144A1
WO2018171144A1 PCT/CN2017/102978 CN2017102978W WO2018171144A1 WO 2018171144 A1 WO2018171144 A1 WO 2018171144A1 CN 2017102978 W CN2017102978 W CN 2017102978W WO 2018171144 A1 WO2018171144 A1 WO 2018171144A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium
lifepo
positive electrode
salt
core
Prior art date
Application number
PCT/CN2017/102978
Other languages
English (en)
French (fr)
Inventor
战鹏
刘敏
顾春芳
黄勇
金鹰
Original Assignee
中天新兴材料有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中天新兴材料有限公司 filed Critical 中天新兴材料有限公司
Publication of WO2018171144A1 publication Critical patent/WO2018171144A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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 invention relates to the technical field of new energy materials, in particular to a cathode material of a lithium ion battery and a preparation method thereof.
  • lithium ion batteries have outstanding advantages such as high energy density, long cycle life, low self-discharge efficiency, no memory effect, and good safety, and are widely used in production and life.
  • cathode material is the material with the highest single-cost cost of single-cell lithium battery. The optimization of its performance is the key to improve the performance of lithium-ion battery, and it is also the focus of current industry, while nickel-cobalt aluminum Lithium acid ternary cathode material is considered to be the most promising ternary cathode material due to its high energy density and good rate performance.
  • lithium nickel cobalt aluminate ternary cathode material has the disadvantages of high surface activity, easy reduction of nickel and high surface alkalinity.
  • the current improvement method is to coat the surface of the material with an inert substance such as Al 2 O 3 and ZnO. , TiO 2 , MgO, AlF 3 , AlPO 4 and the like. These inert coatings are insulative, do not have electrochemical activity, and do not participate in electrochemical reactions, so their coating thickness will directly affect the performance of the cathode material.
  • Olivine-type LiFePO 4 and C-LiFePO 4 have become widely used as positive electrode materials in the lithium battery industry due to their stable structure, good safety, low price, environmental protection and excellent cycle performance. If it is used as a cladding of a ternary positive electrode material, it has excellent electron conductivity and a lithium ion diffusion coefficient compared to a conventional inert coating material, and can achieve good electron and lithium ion transport. In addition, as a coating layer, while enhancing the stability of the core material, it can also participate in the electrochemical reaction. The theoretical gram capacity can reach 170 mAh/g, which can maintain the most significant advantage of the high energy density of the ternary cathode material system.
  • the ternary cathode material needs an oxygen-rich oxidizing atmosphere in its production and preparation process, while the olivine-type LiFePO 4 and carbon-coated LiFePO 4 require an oxygen-reducing reducing atmosphere in the production process, so in the past industry It is difficult to achieve effective combination and large-scale production in production.
  • the present invention provides a positive electrode material which is effective in combining a ternary positive electrode material and LiFePO4, and has a high energy density, and a preparation method thereof.
  • a positive electrode material comprising a core and a cladding layer;
  • the core is Li 1+x Ni 1- yz Co y Al z O 2 , wherein -0.1 ⁇ x ⁇ 0.2, 0 ⁇ y+z ⁇ 0.5, the coating layer is one or both of nano-sized LiFePO 4 and C-LiFePO 4 .
  • the core is an ⁇ -NaFeO 2 type lattice structure
  • the shell layer is an olivine crystal structure
  • the cathode material comprises 1-2 shell layers.
  • the invention also provides a preparation method of the cathode material, the method comprising the following steps:
  • a cathode material is obtained by low-temperature sintering.
  • the preparation of the core material comprises uniformly mixing a ternary precursor Ni 1-y- z Co y Al z (OH) 2 with a lithium salt, and sintering at a high temperature in an oxygen-rich atmosphere to obtain the Li 1+x Ni 1-yz Co y Al z O 2 .
  • the preparing the cladding material comprises uniformly mixing the iron salt, the phosphorus salt, the lithium salt and the carbon source, and then sintering at a high temperature in a reducing atmosphere to obtain nano-scale LiFePO 4 and/or C-LiFePO 4 .
  • the preparing the cladding material comprises uniformly mixing the iron salt, the phosphorus salt and the lithium salt, and then pulverizing at a high temperature in a reducing atmosphere to obtain nano-scale LiFePO 4 .
  • the lithium salt is at least one of lithium carbonate, lithium hydroxide, lithium dihydrogen phosphate, lithium chloride, lithium nitrate, and lithium acetate.
  • the iron salt is at least one of iron phosphate, iron oxide, and ferrous oxalate
  • the phosphorus salt is at least one of iron phosphate, lithium dihydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.
  • the carbon source is at least one of glucose, sucrose, starch, polyethylene glycol, and polyvinyl alcohol.
  • the invention also provides a lithium ion battery comprising the cathode material.
  • the invention adopts a nickel-cobalt-aluminum (NCA) ternary material Li 1+x Ni 1-yz Co y Al z O 2 as a core, one or two of nano-scale LiFePO 4 and C-LiFePO 4 as a coating layer.
  • NCA nickel-cobalt-aluminum
  • the two materials are uniformly mixed by a high-speed mixer, and then the mixed materials are fused together by low-temperature sintering to form a positive electrode material.
  • the positive electrode material provided by the present invention can not reduce Li 1+x Ni.
  • the prepared positive electrode material has stable structure and high energy density, and can simultaneously have Li 1+x Ni 1-yz Co y Al z O 2 and Advantages of nanoscale LiFePO 4 and/or C-LiFePO 4 .
  • FIG. 1 is a schematic view showing a process flow of a method for preparing a positive electrode material according to an embodiment of the present invention
  • NCA positive electrode material not coated with other materials
  • FIG. 3 is a scanning electron micrograph of a positive electrode material of a first example of an embodiment of the present invention
  • FIG. 4 is a scanning electron micrograph of a second example of a positive electrode material according to an embodiment of the present invention.
  • FIG. 5 is an energy spectrum analysis diagram of the positive electrode material shown in FIG. 3;
  • FIG. 6 is an energy spectrum analysis diagram of the positive electrode material shown in FIG. 4;
  • Figure 8 is a discharge curve of the NCA and the first and second positive electrode materials not coated with other materials
  • Figure 9 is a room temperature (25 ° C) cycle life curve of NCA and other first and second positive electrode materials not coated with other materials;
  • Figure 10 is the rate of NCA and other first and second positive electrode materials not coated with other materials. Can compare the map.
  • the positive electrode material provided by the embodiment of the present invention comprises a core and a cladding layer, the core is a nickel cobalt aluminum ternary material ("NCA" for short), and the cladding layer is nanometer LiFePO 4 and C-LiFePO 4 One or two.
  • NCA nickel cobalt aluminum ternary material
  • the NCA is Li 1+x Ni 1-y- z Co y Al z O 2 , wherein -0.1 ⁇ x ⁇ 0.2, 0 ⁇ y+z ⁇ 0.5.
  • the core is an ⁇ -NaFeO 2 type lattice structure; the coating layer is an olivine crystal structure; and the cathode material has 1-2 shell layers.
  • FIG. 1 is a schematic diagram of a process flow of a method for preparing the cathode material.
  • the core is a ternary level material NCA, and the NCA is Li 1+x Ni 1-yz Co y Al z O 2 .
  • the ternary precursor Ni 1-yz Co y Al z (OH) 2 and the lithium salt are uniformly mixed in a mixer according to a molar ratio of a metal element to a lithium element of 1:1.00 to 1.15, and then placed in a mixer.
  • the calcination device it is cooled by pre-calcination and calcination treatment at 600-1000 ° C and an oxygen-rich atmosphere, and then the cooled material is pulverized, sieved, and iron-removed, thereby obtaining a ternary layered material Li 1+x Ni 1-yz Co y Al z O 2 , which is NCA.
  • the lithium salt is one or more selected from the group consisting of lithium carbonate, lithium hydroxide, lithium dihydrogen phosphate, lithium chloride, lithium nitrate, and lithium acetate.
  • the coating layer being one or two of nano-scale LiFePO 4 and C-LiFePO 4 .
  • the coating layer is nano-sized LiFePO 4 .
  • the iron salt, the phosphorus salt and the lithium salt are uniformly mixed in a mixing machine according to a molar ratio of iron, phosphorus and lithium to a ratio of 1:1:1.0-1.15, crushed, dried and placed in a calcining device.
  • Pre-calcination and calcination treatment are carried out at 400-900 ° C and a reducing atmosphere, and then the calcined mixture is cooled, and the cooled material is pulverized, sieved, and iron-removed to obtain nano-scale LiFePO 4 .
  • the coating layer may also be C-LiFePO 4 .
  • the iron salt, the phosphorus salt and the lithium salt are weighed according to the molar ratio of iron, phosphorus and lithium in a ratio of 1:1:1.0-1.15, and the mass ratio of the carbon source to the iron salt is 1:1-10, and the above materials are
  • the mixture is uniformly mixed, pulverized, dried, placed in a crucible into a kiln, pre-calcined and calcined at 400-900 ° C and a reducing atmosphere, and then the calcined mixture is cooled, and the cooled material is cooled. After crushing, sieving, and iron removal, a C-LiFePO 4 positive electrode material is obtained.
  • the coating layer may also be prepared by using nano-scale LiFePO 4 and C-LiFePO 4 , and preparing the nano-scale LiFePO 4 and preparing C-LiFePO 4 .
  • each may be prepared nanoscale LiFePO 4 and C-LiFePO 4, the mixture of both, may also be prepared nanoscale LiFePO 4 and C-LiFePO 4 by an iron salt at the same time, phosphonium salts, lithium salts and a carbon source.
  • the iron salt is at least one of iron phosphate, iron oxide, and ferrous oxalate.
  • the phosphorus salt is at least one of iron phosphate, lithium dihydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.
  • the carbon source is at least one of glucose, sucrose, starch, polyethylene glycol, and polyvinyl alcohol.
  • the positive electrode material is obtained by temperature sintering.
  • the cladding material is LiFePO 4 .
  • LiFePO 4 weighing ⁇ 30 wt% is weighed and mixed with NCA in a mixer, and the speed of the mixer is set to 200-500 rpm.
  • the mixer may be in a dry or wet manner, and the corresponding dispersion system is a solid dispersion system or a liquid dispersion system. Further, the liquid dispersion system uses an organic solvent such as alcohol as a dispersant.
  • NCA/LFP ternary/lithium iron phosphate
  • the LiFePO 4 may also be replaced by C-LiFePO 4 or a mixture of LiFePO 4 and C-LiFePO 4 .
  • the mass fraction of LiFePO 4 was 10% by weight of the positive electrode material.
  • the ternary precursor Ni 1-yz Co y Al z (OH) 2 and lithium hydroxide are mixed in a mixing machine at a molar ratio of metal element to lithium element of 1:1.00-1.15, and then placed in a mixer.
  • the kiln is placed in the kiln, pre-calcined and calcined at 600-1000 ° C and an oxygen-rich atmosphere, and the cooled material is pulverized, sieved and iron-removed to obtain a ternary layered material Li 1+x Ni 1-yz Co y Al z O 2 , which is NCA.
  • the lithium hydroxide may be replaced with one or more of lithium salts such as lithium carbonate, lithium dihydrogen phosphate, lithium chloride, lithium nitrate, and lithium acetate.
  • the iron oxide, lithium carbonate, and diammonium hydrogen phosphate are uniformly mixed in a mixing machine at a molar ratio of iron, phosphorus, and lithium to a ratio of 1:1:1.0-1.15, and then pulverized, dried, and then placed in a crucible.
  • the furnace is introduced into the kiln, pre-calcined and calcined at 400-900 ° C and a reducing atmosphere, and then the calcined mixture is cooled.
  • the cooled material is pulverized, sieved and iron-removed to obtain nano-scale LiFePO 4 . It is ensured that the reducing atmosphere can be assisted by the introduction of an inert gas such as nitrogen.
  • the mixer may be in a wet dispersion mode, and the corresponding dispersion system is a liquid dispersion system. Further, the liquid dispersion system uses an organic solvent such as alcohol as a dispersant. In other embodiments, the mixer may also adopt a dry dispersion method, and the corresponding dispersion system is a solid dispersion system.
  • the mixed material was placed in a vacuum oven and calcined at a temperature of 120 ° C for 3 h to obtain a positive electrode material having a mass fraction of LiFePO 4 of 10 wt%, which may be expressed as "10 wt% LFP + NCA".
  • the mass fraction of LiFePO 4 was 15% by weight of the positive electrode material. Since the preparation method of NCA and nano-scale LiFePO 4 and/or C-LiFePO 4 in this example is the same as that in the first example, it will not be described herein.
  • the positive electrode material in the present embodiment includes a core composed of NCA and a coating layer composed of nano-sized LiFePO 4 and/or C-LiFePO 4 .
  • the core is a layered structure, and the NCA is Li 1+x Ni 1-yz Co y Al z O 2 , wherein -0.1 ⁇ x ⁇ 0.2, 0 ⁇ y+z ⁇ 0.5;
  • the coating layer is an olivine crystal structure.
  • the core is an ⁇ -NaFeO 2 type lattice structure; the coating layer is an olivine crystal structure; and the cathode material includes 1 to 2 shell layers.
  • the positive electrode material provided in the embodiment can be used for preparing a lithium ion battery positive electrode and a lithium ion battery.
  • the method for preparing the positive electrode of the lithium ion battery is as follows: the prepared positive electrode material and the conductive agent carbon black (Super-P) and the binder polyvinylidene fluoride (PVDF) are 92:5:3. The mass ratio is uniformly mixed in a solution of nitrogen methylpyrrolidone (NMP) to form a slurry, and then the slurry is uniformly coated on an aluminum foil, and the aluminum foil coated with the slurry is dried under vacuum at 120 ° C for 4 hours. Lithium ion battery positive electrode.
  • NMP nitrogen methylpyrrolidone
  • the lithium ion battery is prepared by using the positive electrode tab of the lithium ion battery as a positive electrode and the lithium metal plate as a negative electrode, and using a mixed solution of ethylene carbonate and dimethyl carbonate of 1 mol/L lithium hexafluorophosphate as an electrolyte, and
  • the 20 micron thick polyethylene is a diaphragm that is assembled into a CR2032 button lithium ion battery in a glove box (argon atmosphere).
  • the positive electrode composite material provided by the embodiment of the present invention and the button type lithium ion battery fabricated by the above method are subjected to charge and discharge tests on a blue electric charge and discharge tester, and the voltage range thereof is 2.8-4.3V.
  • FIG. 2 is a scanning electron micrograph of the NCA positive electrode material not coated with other materials.
  • the NCA not coated with other materials is a spherical particle having a smooth surface.
  • 3 is a scanning electron micrograph of a positive electrode material according to a first embodiment of the present invention. Referring to FIG. 2, the positive electrode composite material of FIG. 3 is a spherical particle having an attached surface, and the attached matter is flocculent.
  • 4 is a scanning electron micrograph of a second example of a positive electrode material according to an embodiment of the present invention. Referring to FIG. 3, the surface of the positive electrode composite material of FIG. 4 is attached with more flocculent attachments.
  • FIG. 5 is an energy spectrum analysis diagram of the cathode material of the first example shown in FIG. 3
  • FIG. 6 is an energy spectrum analysis diagram of the cathode material of the second example shown in FIG. It can be seen from FIG. 2-6 that the preparation method in the embodiment of the present invention can uniformly coat the nano-scale LiFePO 4 and/or C-LiFePO 4 on the surface of the core NCA material, thereby obtaining a positive electrode with uniform coating layer. material.
  • FIG. 7 is an X-ray diffraction diagram of the NCA and the first and second positive electrode materials which are not coated with other materials, and the “10 wt% LFP+NCA” indicates the first positive electrode material.
  • the crystal structures of the first and second positive electrode materials contain both NCA and LiFePO 4 ("LFP"). It can be understood that a positive electrode material comprising two materials of NCA and LiFePO 4 can be obtained by using the preparation method provided in the embodiment of the present invention.
  • FIG. 8 is a discharge curve of the NCA and the first and second positive electrode materials which are not coated with other materials
  • 10 wt% indicates a positive electrode material with a mass fraction of LiFePO 4 of 10 wt% (“10 wt% LFP” +NCA”)
  • 15 wt% indicates a positive electrode material (“15 wt% LFP + NCA") having a mass fraction of LiFePO 4 of 15 wt%.
  • the initial discharge capacity values of the NCA and the first and second positive electrode materials not coated with other materials can be obtained from the curve of Fig. 8, as shown in the following table:
  • the initial discharge capacity of the positive electrode material provided by the embodiment of the present invention is substantially the same as the initial discharge capacity of the core material NCA, or slightly higher than the core material.
  • the initial discharge capacity of the NCA was not attenuated.
  • FIG. 9 is a room temperature (25 ° C) cycle life curve of NCA and other first and second positive electrode materials not coated with other materials. After circulating at room temperature (25 ° C) for 100 weeks,
  • the capacity retention rate is shown in the following table:
  • FIG. 10 is a comparison diagram of the ratio performance of the NCA and the first and second positive electrode materials which are not coated with other materials.
  • the results in Figure 10 show that 10wt% LFP+NCA, 15wt% LFP+NCA have no significant effect on the rate performance compared to untreated NCA, and at the same magnification, 10wt% LFP+NCA, 15wt% LFP+NCA The discharge gram capacity is significantly higher than the discharge gram capacity of NCA that is not coated with other materials.
  • the positive electrode material provided in the embodiment of the present invention uses NCA (Li 1+x Ni 1-y- z Co y Al z O 2 ) as a core, one or two of nano-scale LiFePO 4 and C-LiFePO 4 as The coating layer is firstly mixed uniformly by a mixer, and then the mixed materials are fused together by low-temperature sintering to form a positive electrode material.
  • the positive electrode material provided by the present invention does not reduce the NCA energy density. Under the premise, the cycle life is improved, and the prepared positive electrode material has stable structure and high energy density, and can simultaneously have the advantages of NCA and nano-scale LiFePO 4 and/or C-LiFePO 4 .
  • the preparation method provided by the invention can effectively inhibit the diffusion of nickel element in the core part and the phase transition of the surface structure, improve the stability and safety of the core nickel-cobalt aluminate ternary layer material, and uniformly mix the materials and the core.
  • the shell material is firmly bonded.

Abstract

提供一种正极材料，包括核芯和包覆层，所述核芯为Li 1+xNi 1-y-zCo yAl zO 2，其中，-0.1≤x≤0.2，0≤y+z≤0.5，所述包覆层为纳米级LiFePO 4、C-LiFePO 4中的一种或两种；还提供一种制备所述正极材料的方法，制备核芯材料，制备包覆层材料，将所述核芯材料和所述包覆层材料混合均匀后，通过低温烧结得到正极材料。

Description

正极材料及其制备方法 技术领域
本发明涉及新能源材料技术领域，尤其涉及一种锂离子电池正极材料及其制备方法。
背景技术
现有技术中，锂离子电池具有能量密度高、循环寿命长、自放电效率小、无记忆效应、安全性好等方面的突出优势，在生产和生活中有广泛应用。而正极材料作为锂离子电池的核心部分之一，是单体锂电池单项成本占比最高的材料，其性能的优化是提升锂离子电池性能的关键，也是当前产业中关注重点，而镍钴铝酸锂三元正极材料由于具有能量密度高、倍率性能好等特性，被认为是最有应用前景的三元正极材料。但镍钴铝酸锂三元正极材料存在表面活性高、镍容易被还原、表面碱性高等缺点，目前通常采用的改进方法是在材料表面包覆一层惰性物质，例如Al2O3、ZnO、TiO2、MgO、AlF3、AlPO4等。这些惰性包覆层呈绝缘性，不具备电化学活性，不参与电化学反应，因而其包覆厚度将直接影响正极材料的性能。
橄榄石型LiFePO4、C-LiFePO4因其结构稳定、安全性好、价格低廉、绿色环保、循环性能优良，已成为目前锂电池行业中广为应用的正极材料。如果用其作为三元正极材料的包层，与传统的惰性包覆材料相比，它具有优异的电子导电性和锂离子扩散系数，可以实现良好的电子和锂离子传输。此外，作为包覆层在提升核芯材料稳定性的同时，还可以参与电化学反应，理论克容量可达170mAh/g，能够维持三元正极材料体系的高能量密度这一最为显著的优势。但三元正极材料在其生产制备过程中需要富氧的氧化性氛围，而橄榄石型LiFePO4、碳包覆LiFePO4生产制备过程所需 的是贫氧的还原性气氛，因此在以往的产业生产中较难实现两者的有效结合及规模化生产。
发明内容
鉴于上述状况，本发明提供一种将三元正极材料与LiFePO4有效结合，且能量密度高的正极材料及其制备方法。
一种正极材料，其中，包括核芯和包覆层；所述核芯为Li1+xNi1- y-zCoyAlzO2，其中，-0.1≤x≤0.2，0≤y+z≤0.5，所述包覆层为纳米级LiFePO4、C-LiFePO4中的一种或两种。
进一步的，所述核芯为α-NaFeO2型晶格结构；所述壳层为橄榄石型晶体结构；所述正极材料包括1-2层壳层。
本发明还提供一种所述正极材料的制备方法，所述方法包括以下步骤：
制备核芯材料；
制备包覆层材料；
将所述核芯材料和所述包覆层材料混合均匀后，通过低温烧结得到正极材料。
进一步的，所述制备核芯材料包括将三元前驱体Ni1-y- zCoyAlz(OH)2与锂盐混合均匀，在富氧气氛中高温烧结得到所述Li1+xNi1-y-zCoyAlzO2。
进一步的，所述制备包覆层材料包括将铁盐、磷盐、锂盐和碳源混合均匀，再在还原性气氛中高温烧结后经粉碎得到纳米级LiFePO4及/或C-LiFePO4。
进一步的，所述制备包覆层材料包括将铁盐、磷盐和锂盐混合均匀，再在还原性气氛中高温烧结后经粉碎得到纳米级LiFePO4。
进一步的，所述锂盐为碳酸锂、氢氧化锂、磷酸二氢锂、氯化锂、硝酸锂、醋酸锂中的至少一种。
进一步的，所述铁盐为磷酸铁、氧化铁、草酸亚铁中的至少一种，所述磷盐为磷酸铁、磷酸二氢锂、磷酸二氢铵、磷酸氢二铵中的至少一种，所述碳源为葡萄糖、蔗糖、淀粉、聚乙二醇、聚乙烯醇中的至少一种。
进一步的，为保证还原性气氛可采用氮气等惰性气体通入的方式协助实现。
本发明还提供一种锂离子电池，包括所述正极材料。
本发明采用镍钴铝(NCA)三元材料Li1+xNi1-y-zCoyAlzO2作为核芯，纳米级LiFePO4、C-LiFePO4中的一种或两种作为包覆层，先通过高速混合机使两者混合均匀，再通过低温烧结使混合的物料融合在一起，形成正极材料，与现有技术相比，本发明提供的正极材料可在不降低Li1+xNi1-y-zCoyAlzO2能量密度的前提下提升其循环寿命，且制成的正极材料结构稳定、能量密度高，可同时具备Li1+xNi1-y-zCoyAlzO2与纳米级LiFePO4及/或C-LiFePO4的优点。
附图说明
图1为本发明实施方式的正极材料的制备方法的工艺流程示意图；
图2为未包覆其他材料的NCA正极材料的扫描电镜图；
图3为本发明实施方式的第一例正极材料的扫描电镜图；
图4为本发明实施方式的第二例正极材料的扫描电镜图；
图5为图3所示的正极材料的能谱分析图；
图6为图4所示的正极材料的能谱分析图；
图7为未包覆其他材料的NCA及第一、二例正极材料的X射线衍射图；
图8为未包覆其他材料的NCA及第一、二例正极材料的放电曲线；
图9为未包覆其他材料的NCA及第一、二例正极材料的室温(25℃)循环寿命曲线；
图10为未包覆其他材料的NCA及第一、二例正极材料的倍率性 能对比图。
具体实施方式
下面将结合本发明实施方式中的附图，对本发明实施方式中的技术方案进行清楚、完整地描述，显然，所描述的实施方式仅仅是本发明一部分实施方式，而不是全部的实施方式。基于本发明中的实施方式，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施方式，都属于本发明保护的范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文所使用的术语“或/及”包括一个或多个相关的所列项目的任意的和所有的组合。
本发明实施方式提供的正极材料包括核芯和包覆层，所述核芯为镍钴铝三元材料(简称“NCA”)，所述包覆层为纳米级LiFePO4、C-LiFePO4中的一种或两种。具体的，所述NCA为Li1+xNi1-y- zCoyAlzO2，其中，-0.1≤x≤0.2，0≤y+z≤0.5。所述核芯为α-NaFeO2型晶格结构；所述包覆层为橄榄石型晶体结构；所述正极材料具有1-2层壳层。
请参考图1，图1所示为所述正极材料的制备方法的工艺流程示意图。
S101，制备核芯，在本实施方式中，所述核芯为三元层级材料NCA，所述NCA为Li1+xNi1-y-zCoyAlzO2。
具体的，将三元前驱体Ni1-y-zCoyAlz(OH)2与锂盐按照金属元素、锂元素的摩尔比为1:1.00-1.15的比例在混料机中混合均匀，然后放入煅烧装置中，在600-1000℃和富氧气氛下经预煅烧和煅烧处理后冷却，再将冷却后的物料经粉碎、过筛、除铁，从而得到三元层状材料Li1+xNi1-y-zCoyAlzO2，即NCA。
所述锂盐为碳酸锂、氢氧化锂、磷酸二氢锂、氯化锂、硝酸锂、醋酸锂中的一种或两种以上。
S102，制备包覆层，所述包覆层为纳米级LiFePO4、C-LiFePO4中的一种或两种。
在本实施方式中，包覆层为纳米级LiFePO4。具体的，将铁盐、磷盐和锂盐按铁、磷、锂元素的摩尔比为1:1:1.0-1.15的比例在混料机中混合均匀，经粉碎、干燥后放入煅烧装置中，在400-900℃和还原性气氛下进行预煅烧、煅烧处理，再将煅烧的混合物料冷却，冷却后的物料经粉碎、过筛、除铁，得到纳米级LiFePO4。
另一种实施方式中，所述包覆层也可以选用C-LiFePO4。铁盐、磷盐和锂盐按铁、磷、锂元素的摩尔比为1:1:1.0-1.15的比例称量，碳源与铁盐的质量比为1:1-10，将上述物料在混料机中混合均匀，经粉碎、干燥后放入匣钵中进入窑炉，在400-900℃和还原性气氛下进行预煅烧、煅烧处理，再将煅烧的混合物料冷却，冷却后的物料经粉碎、过筛、除铁，得到C-LiFePO4正极材料。
再一种实施方式中，所述包覆层也可以选用纳米级LiFePO4和C-LiFePO4两种，采用上述制备纳米级LiFePO4和制备C-LiFePO4的方式制备。具体的，可分别制备纳米级LiFePO4和C-LiFePO4后，将两者混合，也可通过铁盐、磷盐、锂盐和碳源同时制备纳米级LiFePO4和C-LiFePO4。
为保证还原性气氛可采用氮气等惰性气体通入的方式协助实现。所述铁盐为磷酸铁、氧化铁、草酸亚铁中的至少一种。所述磷盐为磷酸铁、磷酸二氢锂、磷酸二氢铵、磷酸氢二铵中的至少一种。所述碳源为葡萄糖、蔗糖、淀粉、聚乙二醇、聚乙烯醇中的至少一种。
S103，将所述核芯材料和所述包覆层材料混合均匀后，通过低 温烧结得到正极材料。
在本实施方式中，包覆层材料为LiFePO4。具体的，称取质量分数≤30wt％的LiFePO4同NCA放入混合机中混合，设置混合机的转速为200-500rpm。所述混合机可采用干式或湿式两种分散方式，其对应分散体系分别为固态分散体系或液态分散体系，进一步的，所述液态分散体系采用添加酒精等有机溶剂作为分散剂。
混合5h后，将物料置于真空烘箱，在100-250℃温度下煅烧3h，即得三元/磷酸铁锂(简称“NCA/LFP”)的核壳结构的正极材料。
在其他实施方式中，所述LiFePO4也可替换为C-LiFePO4或LiFePO4和C-LiFePO4的混合物。
下面再详细叙述两例LiFePO4的质量分数不同的正极复合材料及其制备方法。
第一例，LiFePO4的质量分数为10wt％的正极材料。
首先，将三元前驱体Ni1-y-zCoyAlz(OH)2与氢氧化锂按金属元素、锂元素的摩尔比为1:1.00-1.15的比例在混料机中混合均匀，然后放入匣钵中进入窑炉，在600-1000℃和富氧气氛下进行预煅烧、煅烧处理，冷却后的物料经粉碎、过筛、除铁，从而得到三元层状材料Li1+xNi1-y-zCoyAlzO2，即NCA。在其他实施方式中，所述氢氧化锂也可替换成碳酸锂、磷酸二氢锂、氯化锂、硝酸锂、醋酸锂等锂盐中的一种或两种以上。
然后，将氧化铁、碳酸锂、磷酸氢二铵按铁、磷、锂元素的摩尔比为1:1:1.0-1.15的比例在混料机中混合均匀，经粉碎、干燥后放入匣钵中进入窑炉，在400-900℃和还原性气氛下进行预煅烧、煅烧处理，再将煅烧的混合物料冷却，冷却后的物料经粉碎、过筛、除铁，得到纳米级LiFePO4，为保证还原性气氛可采用氮气等惰性气体通入的方式协助实现。
最后，将10g纳米级LiFePO4与90gNCA放入混合机中混合5h，设置混合机的转速为260rpm。所述混合机可采用湿式分散方式，其对应的分散体系为液态分散体系，进一步的，所述液态分散体系采用添加酒精等有机溶剂作为分散剂。在其他实施方式中，所述混合机也可采用干式分散方式，其对应的分散体系为固态分散体系。
将混合后的物料置于真空烘箱，在120℃温度下煅烧3h，即得LiFePO4的质量分数为10wt％的正极材料，所述正极材料可表示为“10wt％LFP+NCA”。
第二例，LiFePO4的质量分数为15wt％的正极材料。由于本例中NCA与纳米级LiFePO4及/或C-LiFePO4的制成方法与第一例中的方法相同，在此不再赘述。
在第二例的制备方法中，将15g纳米级LiFePO4与85gNCA放入混合机中分散5h，将混合好的物料放入真空干燥箱中120℃煅烧3h，从而得到LiFePO4的质量分数为15wt％的正极材料，所述正极材料可表示为“15wt％LFP+NCA”。
可以理解的，本实施方式中的正极材料包括由NCA组成的核芯以及由纳米级LiFePO4及/或C-LiFePO4组成的包覆层。具体的，所述核芯为层状结构，所述NCA为Li1+xNi1-y-zCoyAlzO2，其中，-0.1≤x≤0.2，0≤y+z≤0.5；所述包覆层为橄榄石型晶体结构。除此之外，所述核芯为α-NaFeO2型晶格结构；所述包覆层为橄榄石型晶体结构；所述正极材料包括1～2层壳层。
本实施方式中提供的正极材料可用于制备锂离子电池正极及锂离子电池。
具体的，制备锂离子电池正极的方法为：将配置好的正极材料与导电剂炭黑(Super-P)、粘结剂聚偏氟乙烯(PVDF)以92:5:3 的质量比在氮甲基吡咯烷酮(NMP)溶液中混合均匀形成浆料，然后将所述浆料均匀的涂覆在铝箔上，及将涂覆浆料的铝箔在120℃下真空干燥4h后制备成锂离子电池正极。
制备锂离子电池的方法为：将所述锂离子电池正极极片作为正极，以金属锂片作为负极，采用1mol/L六氟磷酸锂的碳酸乙烯酯和碳酸二甲酯的混合溶液作为电解液，并以20微米厚的聚乙烯为隔膜，在手套箱中(氩气气氛)组装成CR2032型纽扣锂离子电池。
采用本发明实施方式中提供的正极复合材料、以上述方法制成的纽扣式锂离子电池，在蓝电充放电测试仪上进行充放电测试，其电压范围为2.8-4.3V。
请参考图2-6，图2为未包覆其他材料的NCA正极材料的扫描电镜图，由图2可知，未包覆其他材料的NCA为表面较光滑的圆球颗粒。图3为本发明实施方式的第一例正极材料的扫描电镜图，对比图2，图3中的正极复合材料为表面有附着物的圆球颗粒，所述附着物呈絮状。图4为本发明实施方式的第二例正极材料的扫描电镜图，对比图3，图4中的正极复合材料的表面附有更多的絮状附着物。图5为图3所示的第一例正极材料的能谱分析图，图6为图4所示的第二例正极材料的能谱分析图。从图2-6可以看出，采用本发明实施方式中的制备方法能够使纳米级LiFePO4及/或C-LiFePO4均匀的包覆在核芯NCA材料表面，从而得到包覆层均匀的正极材料。
请参考图7，图7为未包覆其他材料的NCA及第一、二例正极材料的X射线衍射图，图中所示“10wt％LFP+NCA”表示第一例正极材料，图中所示“15wt％LFP+NCA”表示第二例正极材料。从图7中可以看出，第一、二例正极材料的晶体结构中均包含NCA及 LiFePO4(“LFP”)两种物质。可以理解的，使用本发明实施方式中提供的制备方法可以得到包含NCA及LiFePO4两种物质的正极材料。
请参考图8，图8为未包覆其他材料的NCA及第一、二例正极材料的放电曲线，图中“10wt％”表示LiFePO4的质量分数为10wt％的正极材料(“10wt％LFP+NCA”)，图中“15wt％”表示LiFePO4的质量分数为15wt％的正极材料(“15wt％LFP+NCA”)。由图8曲线可得到未包覆其他材料的NCA及第一、二例正极材料的初始放电容量值，如下表所示：
材料 初始放电容量(mAh/g)
NCA 189.9
10wt％LFP+NCA 192.1
15wt％LFP+NCA 191
由上表数据对比可知，因LiFePO4(LFP)亦有容量贡献，本发明实施方式提供的正极材料的初始放电容量与核芯材料NCA的初始放电容量基本保持一致，或略高于核芯材料NCA的初始放电容量，未有衰减。
请参考图9，图9为未包覆其他材料的NCA及第一、二例正极材料的室温(25℃)循环寿命曲线。室温(25℃)循环100周后，
容量保持率如下表所示：
材料 容量保持率
NCA 87.82％
10wt％LFP+NCA 91.33％
15wt％LFP+NCA 91.63％
图9及上表对比可知，通过在NCA材料表面包覆LiFePO4(LFP)，可以在不降低NCA材料容量的同时，显著改善材料的 循环稳定性，提升三元层状材料NCA的使用寿命。
请参考图10，图10为未包覆其他材料的NCA及第一、二例正极材料的倍率性能对比图。图10的结果表明，10wt％LFP+NCA、15wt％LFP+NCA同未处理的NCA相比，其倍率性能未受明显影响，且相同倍率下，10wt％LFP+NCA、15wt％LFP+NCA的放电克容量明显高于未包覆其他材料的NCA的放电克容量。
本发明实施方式中提供的正极材料采用NCA(Li1+xNi1-y- zCoyAlzO2)作为核芯，纳米级LiFePO4、C-LiFePO4中的一种或两种作为包覆层，先通过混合机使两者混合均匀，再通过低温烧结使混合的物料融合在一起，形成正极材料，与现有技术相比，本发明提供的正极材料在不降低NCA能量密度的前提下提升其循环寿命，且制成的正极材料结构稳定、能量密度高，可同时具备NCA与纳米级LiFePO4及/或C-LiFePO4的优点。本发明提供的制备方法能够有效抑制核心部分镍元素的扩散以及表面结构相变的发生，提高芯部镍钴铝酸锂三元层状材料的稳定性和使用安全性，物料间混合均匀且核壳材料之间结合牢固。
以上实施方式仅用以说明本发明的技术方案而非限制，尽管参照以上较佳实施方式对本发明进行了详细说明，本领域的普通技术人员应当理解，可以对本发明的技术方案进行修改或等同替换都不应脱离本发明技术方案的精神和范围。

Claims (10)

  1. 一种正极材料，其特征在于，包括核芯和包覆层；所述核芯为Li1+xNi1-y-zCoyAlzO2，其中，-0.1≤x≤0.2，0≤y+z≤0.5，所述包覆层为纳米级LiFePO4、C-LiFePO4中的一种或两种。
  2. 如权利要求1所述的正极材料，其特征在于，所述核芯为α-NaFeO2型晶格结构；所述壳层为橄榄石型晶体结构；所述正极材料包括1-2层壳层。
  3. 一种如权利要求1或2所述的正极材料的制备方法，其特征在于，所述方法包括以下步骤：
    制备核芯材料；
    制备包覆层材料；
    将所述核芯材料和所述包覆层材料混合均匀后，通过低温烧结得到正极材料。
  4. 如权利要求3所述的制备方法，其特征在于，所述制备核芯材料包括将三元前驱体Ni1-y-zCoyAlz(OH)2与锂盐混合均匀，在富氧气氛中高温烧结得到所述Li1+xNi1-y-zCoyAlzO2。
  5. 如权利要求3所述的制备方法，其特征在于，所述制备包覆层材料包括将铁盐、磷盐、锂盐和碳源混合均匀，再在还原性气氛中高温烧结后经粉碎得到纳米级LiFePO4及/或C-LiFePO4。
  6. 如权利要求3所述的制备方法，其特征在于，所述制备包覆层材料包括将铁盐、磷盐和锂盐混合均匀，再在还原性气氛中高温烧结后经粉碎得到纳米级LiFePO4。
  7. 如权利要求4-6任一项所述的制备方法，其特征在于，所述锂盐为碳酸锂、氢氧化锂、磷酸二氢锂、氯化锂、硝酸锂、醋酸锂中的至少一种。
  8. 如权利要求5或6任一项所述的制备方法，其特征在于， 所述铁盐为磷酸铁、氧化铁、草酸亚铁中的至少一种，所述磷盐为磷酸铁、磷酸二氢锂、磷酸二氢铵、磷酸氢二铵中的至少一种，所述碳源为葡萄糖、蔗糖、淀粉、聚乙二醇、聚乙烯醇中的至少一种。
  9. 如权利要求5所述的制备方法，其特征在于，所述还原性气氛可采用氮气等惰性气体通入的方式协助实现。
  10. 一种锂离子电池，其特征在于，包括如权利要求1-2任一项所述的正极材料。
PCT/CN2017/102978 2017-03-24 2017-09-22 正极材料及其制备方法 WO2018171144A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201710184088.0 2017-03-24
CN201710184088.0A CN108630936A (zh) 2017-03-24 2017-03-24 正极材料及其制备方法

Publications (1)

Publication Number Publication Date
WO2018171144A1 true WO2018171144A1 (zh) 2018-09-27

Family

ID=63584126

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/102978 WO2018171144A1 (zh) 2017-03-24 2017-09-22 正极材料及其制备方法

Country Status (2)

Country Link
CN (1) CN108630936A (zh)
WO (1) WO2018171144A1 (zh)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110660978B (zh) * 2019-08-29 2022-07-15 孚能科技(赣州)股份有限公司 核壳结构的锂离子电池正极材料及其制备方法和正极片以及锂离子电池及其应用
CN113066963B (zh) * 2021-03-22 2022-06-28 上海空间电源研究所 一种全固态薄膜锂电池正极薄膜的制造方法及锂电池
WO2024020795A1 (zh) * 2022-07-26 2024-02-01 宁德时代新能源科技股份有限公司 一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104701527A (zh) * 2013-12-05 2015-06-10 陕西汇沣新能源科技有限公司 一种锂离子电池正极材料镍钴铝酸锂的制备方法
CN106299353A (zh) * 2015-06-01 2017-01-04 龙能科技（苏州）有限公司 镍钴铝酸锂复合材料及其制备方法和应用
CN106299355A (zh) * 2015-10-15 2017-01-04 江西省金锂科技股份有限公司 一种纳米碳包覆磷酸铁锂正极材料的制备方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103178251B (zh) * 2013-03-15 2017-07-28 宁德新能源科技有限公司 锂离子动力电池正极材料及包含该材料的锂离子动力电池
CN104577093A (zh) * 2015-01-13 2015-04-29 海宁美达瑞新材料科技有限公司 一种表面包覆改性的锂离子电池正极材料及其制备方法
CN105355880B (zh) * 2015-11-13 2018-06-08 山东精工电子科技有限公司 一种LiFePO4/C改性三元正极材料的制备方法
CN105552324A (zh) * 2015-12-15 2016-05-04 天津斯特兰能源科技有限公司 一种磷酸铁锂包覆镍钴锰酸锂复合材料的制备方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104701527A (zh) * 2013-12-05 2015-06-10 陕西汇沣新能源科技有限公司 一种锂离子电池正极材料镍钴铝酸锂的制备方法
CN106299353A (zh) * 2015-06-01 2017-01-04 龙能科技（苏州）有限公司 镍钴铝酸锂复合材料及其制备方法和应用
CN106299355A (zh) * 2015-10-15 2017-01-04 江西省金锂科技股份有限公司 一种纳米碳包覆磷酸铁锂正极材料的制备方法

Also Published As

Publication number Publication date
CN108630936A (zh) 2018-10-09

Similar Documents

Publication Publication Date Title
CN109336193B (zh) 多元素原位共掺杂三元材料前驱体及其制备方法和应用
US20210367233A1 (en) Ternary positive electrode material and preparation method therefor, and lithium-ion battery
CN104134801B (zh) 氮化碳-石墨烯包覆磷酸铁锂复合正极材料及其制备方法
CN109390563B (zh) 改性磷酸铁锂正极材料及其制备方法、正极片、锂二次电池
WO2022011939A1 (zh) 无钴正极材料及其制备方法以及锂离子电池正极和锂电池
Xiao et al. Effect of MgO and TiO2 Coating on the Electrochemical Performance of Li‐Rich Cathode Materials for Lithium‐Ion Batteries
US11791452B2 (en) Positive electrode for solid-state batteries, solid-state battery and method for producing solid-state battery
CN105261740A (zh) 一种锂电池正极材料，其制备方法及含有该材料的锂离子电池
CN108630904B (zh) 一种正极复合材料及其制备方法和应用
Chaudhary et al. Surface modification of cathode materials for energy storage devices: A review
EP3694035A1 (en) Anode layer and all solid state battery
CN112635722B (zh) 一种锂离子电池复合正极材料及制备方法
CN114665058A (zh) 一种锂离子电池正极材料磷酸锰铁锂的制备方法
WO2018171144A1 (zh) 正极材料及其制备方法
KR102342216B1 (ko) 부극층 및 전고체 전지
US20200006804A1 (en) Lithium Ion Battery Silicate Positive Electrode Material, and Preparation and Application Thereof
CN110459764B (zh) 一种锂离子电池正极材料及其制备方法与应用
CN116014104A (zh) 富锂镍系正极材料及其制备方法、正极片与二次电池
Du et al. A three volt lithium ion battery with LiCoPO4 and zero-strain Li4Ti5O12 as insertion material
CN108878873B (zh) 磷酸铁锂正极材料改性表面结构及其制备方法和应用
CN113582253A (zh) 一种四元正极材料及其制备方法和应用
CN102295280A (zh) 一种改善锂离子电池正极材料磷酸铁锂的电化学性能的方法
CN108682847B (zh) 一种多壳层中空微球形α-Fe2O3材料、制备方法及其应用
CN115863797A (zh) 一种适用于高压正极的补锂剂及其制备方法和应用
CN105375004B (zh) 一种长寿命高能锂二次电池正极材料及其制备方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17901486

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17901486

Country of ref document: EP

Kind code of ref document: A1