WO2023197483A1 - 一种纳米磷酸铁锰锂的水热合成方法 - Google Patents

一种纳米磷酸铁锰锂的水热合成方法 Download PDF

Info

Publication number
WO2023197483A1
WO2023197483A1 PCT/CN2022/110407 CN2022110407W WO2023197483A1 WO 2023197483 A1 WO2023197483 A1 WO 2023197483A1 CN 2022110407 W CN2022110407 W CN 2022110407W WO 2023197483 A1 WO2023197483 A1 WO 2023197483A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium iron
hydrothermal synthesis
synthesis method
autoclave
lithium
Prior art date
Application number
PCT/CN2022/110407
Other languages
English (en)
French (fr)
Inventor
�田一弘
Original Assignee
深圳沃伦特新能源科技有限公司
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 深圳沃伦特新能源科技有限公司 filed Critical 深圳沃伦特新能源科技有限公司
Priority to EP22937121.6A priority Critical patent/EP4393875A1/en
Publication of WO2023197483A1 publication Critical patent/WO2023197483A1/zh

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/45—Phosphates containing plural metal, or metal and ammonium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • 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
    • H01M4/36—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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • 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 raw material preparation for lithium ion batteries, and in particular to a hydrothermal synthesis method of nanometer lithium iron manganese phosphate.
  • Lithium iron phosphate with an olivine structure has received great attention in the field of secondary lithium-ion batteries because of its safety, low price, and environmental friendliness. Due to its poor electronic conductivity and only one-dimensional ion transmission channel, its ion conductivity is also poor, resulting in the material's electrochemical performance not being able to be effectively exerted. In addition, because its discharge voltage platform is around 3.45V, the energy density is low. By replacing some iron atoms with manganese atoms to prepare lithium iron manganese phosphate materials, a phosphate material with an olivine structure (LiFe x Mn 1-x PO 4 ) can still be obtained. This material exhibits two discharge platforms of 3.45V and 4.0V.
  • the technical routes for synthesizing lithium iron manganese phosphate are mainly divided into two categories.
  • One is the solid phase method.
  • the basic principle of this method is that a solid phase synthesis reaction occurs between solid reactant particles at high temperature through surface diffusion, and the product The particle control and batch stability of the product need to be improved;
  • the other type is the liquid phase method, including the hydrothermal method using water as the reaction medium and the solvothermal method using organic solvents as the reaction medium.
  • liquid-phase synthesis has the advantages of uniform physical phase and easy control of particle size, and can obtain nanoscale particles.
  • the use of organic solvents as the medium has a good effect on reducing the pressure in the reactor and controlling the particle size of the product.
  • the patent with the publication number CN104582878A uses triethanolamine as a solvent
  • the patent with the publication number CN111777051A uses ethylene glycol as the solvent and also acts as a surfactant
  • the patent with the publication number CN104583130A uses glycerol as the solvent
  • the patent with the publication number CN104918888A uses ethylene glycol as the solvent and surfactant.
  • Various alcohols are used as solvents to synthesize nanoscale products.
  • methods for controlling particle size include: (1) using surfactants, such as the technology in ZL200710058352.2; (2) controlling process parameters such as reaction temperature and pH value, such as the technology in ZL202010031395.3 Technology can achieve the purpose of reducing particle size.
  • surfactants such as the technology in ZL200710058352.2
  • process parameters such as reaction temperature and pH value, such as the technology in ZL202010031395.3 Technology can achieve the purpose of reducing particle size.
  • the particle size of the material only reaches about 100 nanometers in one dimension. The industry still needs to further reduce the particle size, and the material is in a flaky shape, which is not conducive to increasing the packing density.
  • the main steps are to dissolve soluble ferrous salts and manganese salts, phosphoric acid and lithium hydroxide in a certain proportion, mix them in a reactor, and then raise the temperature to 120 ⁇ 374°C (the critical temperature of water), lithium iron manganese phosphate crystals can be prepared in a wide temperature range, but the morphology and particle size of the crystals are different. Generally speaking, the higher the reaction temperature, the smaller the particles of the crystals prepared. The smaller, the better the electrochemical performance.
  • the raw materials participating in the hydrothermal reaction are first dissolved and then added to the reaction kettle.
  • the raw materials are molecularly mixed. But in fact, at normal temperature or slightly higher than normal temperature, after the reaction raw material solution is mixed, new materials are formed immediately.
  • the precipitation mixture reacts as follows:
  • Li 3 PO 4 ⁇ and Fe 3 (PO 4 ) 2 ⁇ dissolve one after another, releasing Li + , Fe 2+ and PO 4 3- , and these ions recombine to form lithium iron phosphate.
  • the mechanism is the same when part of manganese is used to replace iron. With such a process, the goal of actual molecular-level mixing cannot be achieved, and a large number of crystal nuclei cannot be formed in a short period of time. Therefore, the particle size will be difficult to decrease due to the small number of crystal nuclei.
  • the present invention provides a hydrothermal synthesis method of nano-lithium iron manganese phosphate, by preheating the reactant raw material liquid to make it higher than lithium phosphate (produced after mixing lithium hydroxide and phosphoric acid or recovered from the mother liquor). ) starts to dissolve, and then mixed with ferrous sulfate (or part of the iron element is replaced by manganese) at high temperature. During the mixing process, the raw materials are all in liquid phase, which is a true molecular level mixing and can produce a large number of crystal nuclei instantly. , thus forming nanometer lithium iron manganese phosphate particles.
  • the present invention adopts the following technical solutions.
  • a hydrothermal synthesis method of nanometer lithium iron manganese phosphate including the following steps:
  • step (4) Mix the lithium iron manganese phosphate powder obtained in step (4) with the carbon source, and bake at 700°C for 4 hours under the protection of an inert gas to obtain carbon-coated lithium iron manganese phosphate.
  • step (4) the mother liquor filtered in step (4) and the washing water used to wash the filter cake are combined, and after evaporation and concentration, the lithium phosphate is recovered.
  • step (4) was vacuum dried at 110-120°C for 12 hours.
  • ferrous sulfate and manganese sulfate are finished crystals or liquids before crystallization of ferrous sulfate and manganese sulfate; the lithium phosphate is obtained by neutralizing lithium hydroxide and phosphoric acid, or recovered from the mother liquor. .
  • lithium iron manganese phosphate powder and the carbon source are mixed evenly according to a mass ratio of 100: (15-20).
  • the carbon source is glucose
  • the present invention has the following beneficial effects:
  • the hydrothermal synthesis method of nanometer lithium iron manganese phosphate of the present invention uses high-temperature mixed reaction raw materials to create true molecular-level mixing reaction starting conditions.
  • the particles of the produced material are uniform and the morphology is similar to that of ordinary hydrothermal products.
  • the flake shape turns to a spherical shape, and the three-dimensional scale can reach the nanometer level, which is conducive to shortening the lithium ion diffusion path, conducive to the contact between the positive electrode active material particles after the electrode material is added to the pole piece, and is fundamentally conducive to improving the electrical conductivity of the material. chemical properties and extended cycle life.
  • the hydrothermal synthesis method of nano-lithium iron manganese phosphate of the present invention controls the temperature of the reaction raw materials, changes the number of crystal nuclei generated, and ultimately controls the particle size to obtain uniform nano-scale product particles, and the process conditions are mild. , easy to operate.
  • Nano-lithium iron manganese phosphate obtained by the hydrothermal synthesis method of the present invention is used as a positive electrode material for lithium-ion batteries.
  • the prepared lithium-ion battery has high-rate discharge performance, and the low-temperature discharge performance is also effectively improved.
  • Figure 1 is a morphology diagram of lithium iron manganese phosphate prepared in Example 1 of the present invention.
  • Figure 2 is a morphology diagram of lithium iron manganese phosphate prepared in Comparative Example 1 of the present invention
  • Figure 3 is a 25°C, 0.2C charge and discharge curve of the battery prepared in Example 1 of the present invention.
  • a hydrothermal synthesis method of nanometer lithium iron manganese phosphate including the following steps:
  • Step 2 Filtration, washing and drying of the product
  • the pink-white powder prepared in the second step was mixed with glucose at a mass ratio of 100:15, and calcined at 700°C for 4 hours under nitrogen protection to obtain carbon-coated lithium iron manganese phosphate (LiFe 0.5 Mn 0.5 PO 4 /C )product.
  • the lithium iron manganese phosphate/carbon prepared above was used as the battery cathode material, and its charge and discharge performance was tested. Specifically: mix the lithium iron manganese phosphate/carbon, acetylene black, and 60% polytetrafluoroethylene emulsion obtained above in a mass ratio of 7:2:1, roll them into sheets with a thickness of 0.10 to 0.15mm, and mix them with The aluminum foils were pressed together and vacuum dried at 120°C for 12 hours to prepare the battery positive electrode. Use the metal lithium sheet negative electrode, 1M LiPF 6 solution as the electrolyte, and cell gard 2300 as the separator. Assemble the button battery with the above-mentioned positive electrode. Charge and discharge at 25°C at a rate of 0.2C and 1C, and then at -20°C at a rate of 0.2 C discharge, the voltage range of charge and discharge is 4.5 ⁇ 2.3V. The test results are shown in Table 1 and Figure 3.
  • the morphology of the product produced in this embodiment is shown in Figure 1. It can be seen that the particles of the material are uniform, the shape is spherical, and the three-dimensional scale reaches the nanometer level, which is conducive to shortening the lithium ion diffusion path and is conducive to the processing of electrode materials. The contact between the positive electrode active material particles after forming the electrode sheet.
  • Example 1 The lithium phosphate in slurry A in Example 1 was replaced with the lithium phosphate recovered from the mother liquor, and other preparation steps were the same as in Example 1.
  • Example 1 The slurry A, slurry B and final hydrothermal synthesis reaction temperature in Example 1 were all set to 140°C, the reaction time was set to 4 hours, and other preparation steps were the same as in Example 1.
  • the hydrothermal synthesis reaction is carried out according to conventional feeding techniques, and the starting temperature of all reaction raw material liquids is room temperature.
  • the morphology of the product prepared in this comparative example is shown in Figure 2.
  • the reaction raw materials are mixed under normal temperature conditions. During the subsequent temperature rise process, the reaction starts before reaching the set reaction temperature. First, the intermediate products - lithium phosphate and blue iron manganese phosphate in precipitated form are generated. When the temperature rises, the intermediate product begins to dissolve and generates the target product lithium iron manganese phosphate. It takes about 10 minutes to rise from 120°C to 150°C (there is a period of temperature stagnation due to endothermic dissolution). The nucleation of ions depends on the dissolution of the intermediate product. To release, therefore, there are insufficient nucleation ions, and the particles of the product are relatively large.
  • the volume of the reactor becomes larger, for example, from 10L to 1M 3 , the volume of the reactor is enlarged by 100 times, and theoretically its heat transfer surface area is only enlarged by 21 times, resulting in negative effects after the expansion of the reactor.
  • the lithium iron manganese phosphate formed in the low-temperature section not only has ion misalignment problems in the crystal structure of the material, but also has poor particle uniformity, larger particle size, and poor performance. To make matters worse, in fact, production-type reactors are often larger. Even if coils can be added to increase the heat transfer area, the negative effects cannot be avoided.
  • Example 1 159.7 149.1 132.1
  • Example 2 159.6 148.5 131.8
  • Example 3 158.9 147.7 129.7 Comparative example 1 148.5 138.8 114.6
  • the high-temperature feeding method creates conditions for molecular-level mixing between the reaction raw materials, and under this condition, a large number of crystal nuclei are instantly generated, and there are a large number of free crystallization ions in the reaction system. , thereby reversing the insufficient state of crystallizing ions caused by solid precursors existing in previous technologies.
  • the direction-selective growth trend of crystals is replaced by rapid crystal growth, a large number of crystal nuclei grow rapidly, and the final product has fine particles and high sphericity, which is beneficial to increasing the compaction density of the electrode and exerting the electrochemical capacity.
  • the lithium iron manganese phosphate material exhibits excellent electrochemical performance.
  • the preparation method of the present invention is simple and economical, the process conditions are mild and easy to operate, it solves the negative effect of equipment amplification in conventional technology, and is suitable for industrial large-scale production applications.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Nanotechnology (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本发明涉及锂电池原料制备技术领域，尤其涉及一种纳米磷酸铁锰锂的水热合成方法，包括以下步骤：将磷酸锂和水混合后加入高压釜1中，搅拌下从室温加热至140-150℃，得到料浆A；将硫酸亚铁和硫酸锰用水溶解，加入高压釜2中，加热至140-150℃，得到料浆B；将高压釜3加热到140-150℃，向高压釜3中并流加入料浆A和料浆B，搅拌，维持140-150℃反应2-4小时；停止加热，降温，打开出料阀，过滤生成物，洗涤滤饼，真空干燥，得到磷酸铁锰锂粉末，再进行碳包覆处理。本发明采用高温混合反应原料，创造了真正的分子级混合的反应起始条件，制得的材料颗粒均匀，三维尺度均可达到纳米级别，有利于锂离子扩散路径的缩短，从根本上有利于提高材料的电化学性能及延长循环寿命。

Description

一种纳米磷酸铁锰锂的水热合成方法
本公开基于申请号为202210381172.2，申请日为2022年4月12日的中国专利申请提出，并要求该篇中国专利申请的优先权，该篇中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本发明涉及锂离子电池原料制备技术领域，尤其涉及一种纳米磷酸铁锰锂的水热合成方法。
背景技术
具有橄榄石结构的磷酸铁锂，因其具有的安全性、价廉性、环境友好性，在二次锂离子电池领域受到极大关注。由于其本身的电子导电性较差，且仅具有一维离子传输通道，其离子导电性也较差，造成此材料的电化学性能不能有效发挥。另外，由于其放电电压平台在3.45V左右，能量密度较低。用锰原子替换部分铁原子，制备磷酸铁锰锂材料，仍可得到具有橄榄石结构的磷酸盐材料(LiFe xMn 1-xPO 4)，此材料呈现3.45V和4.0V两个放电平台，锰的替代在理论上，提高了材料的能量密度，但是，材料的导性和离子扩散性能进一步降低，影响其电化学性能的发挥。为了解决上述问题，减小粒径缩短离子以扩散距离和碳包覆以提高电子导电性是最有效的两种方法。已有许多研究表明，将材料的粒径制备成纳米级，可使其达到近于其理论容量，同时也使倍率性能和低温性能得到提高。
现有技术中，合成磷酸铁锰锂的技术路线主要分两类，一类是固相法，此方法的基本原理是在高温下固体反应物颗粒之间通过表面扩散发生固相合成反应，产物的颗粒控制和产品的批量稳定性有待提高；另一类是液相法，包括以水为反应介质的水热法和以有机溶剂为反应介质的溶剂热法。与固相法相比，液相合成具有物相均匀和粒径易控且可得到纳米级颗粒的优点。在液相合成法之溶剂热合成技术中，采用有机溶剂为介质，对降低反应釜内的压力、控制产 物粒径方面都有较好的效果。例如，公开号为CN104582878A的专利用三乙醇胺作为溶剂，公开号为CN111777051A的专利以乙二醇为溶剂兼做表面活性剂，公开号为CN104583130A的专利以甘油为溶剂，公开号为CN104918888A的专利以各种醇类为溶剂，合成出了纳米级的产物。但是，以有机物为溶剂，在大规模产业化应用方面，存在环保问题，如生产现场防爆、工艺中产生的有机废水处理增加生产成本等问题。采用水为介质的水热合成技术，上述问题不突出。现有水热合成技术中，控制粒径的方法有：(1)采用表面活性剂，例如ZL200710058352.2中的技术；(2)控制反应温度和pH值等工艺参数，例如ZL202010031395.3中的技术，都可以达到减小粒径的目的。但是，材料的粒径仅在一维维度上达到100左右的纳米级，业界对粒径的进一步下降仍有需求，且材料呈片状，不利于堆积密度的提高。目前已有的水热制备磷酸铁锰锂技术路线中，主要采取的步骤是将可溶性亚铁盐和锰盐、磷酸和氢氧化锂按一定比例溶解，于反应釜中混合后，升温至120～374℃(水的临界温度)，在一个较广的温度范围内均可制得磷酸铁锰锂晶体，但晶体的形貌和颗粒大小不同，一般来说反应温度越高制备的晶体的颗粒越小，电化学性能越好。为了获得细小的磷酸铁锰锂颗粒，需采用较高的反应温度并辅以表面活性剂、有机溶剂以达到细化颗粒的目的，存在的缺点是在较高温度下反应，反应体系的自生压力较大，由此带来设备投资大、操作控制难的问题；另外，表面活性剂存留于母液中，母液蒸发过程会产生大量泡沫难以控制，且生产工艺中出现含有机物的废水，增加后续处理成本。事实上，提高反应温度和利用表面活性剂，都未从结晶过程的根本上着手以控制粒径。因为，表面上看，参与水热反应的原料首先被溶解，再加入反应釜，原料之间是分子混合，但事实上，在常温或稍高于常温下，反应原料溶液混合之后，立即形成新的沉淀混合物，反应如下：
LiOH+H 3PO 4+FeSO 4→Li 3PO 4↓+Fe 3(PO 4) 2↓+Li 2SO 4
随着温度的升高，Li 3PO 4↓和Fe 3(PO 4) 2↓相继溶解，释放出Li +、Fe 2+和PO 4 3-，这些离子再重新结合生成磷酸铁锂。用部分锰代替铁的情况下，机理相同。以这样的过程，达不到事实上的分子级混合的目标，就不能在短时间内形成大量的晶核，因此，颗粒粒径就会因晶核少而难以下降。
需要解决上述问题。
发明内容
为了解决上述问题，本发明提供一种纳米磷酸铁锰锂的水热合成方法，通过对反应物原料液预加热，使其高于磷酸锂(氢氧化锂与磷酸混合后产生的或母液回得到的)开始溶解的温度，再于高温下与硫酸亚铁(或其中部分铁元素被锰替代)混合，混合过程中原料均是液相，是真正的分子级混合，并可瞬间产生大量晶核，由此形成纳米磷酸铁锰锂颗粒。本发明采用如下技术方案。
一种纳米磷酸铁锰锂的水热合成方法，包括以下步骤：
(1)将磷酸锂和水混合后加入高压釜1中，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，搅拌下从室温加热至140-150℃，保温备用，得到料浆A；
(2)将硫酸亚铁和硫酸锰用水溶解，加入高压釜2中，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，加热至140-150℃，保温备用，得到料浆B；
(3)将高压釜3加热到140-150℃，打开进料阀和安全排气阀，向高压釜3中并流加入料浆A和料浆B，搅拌，维持140-150℃反应2-4小时；
(4)在140-150℃下保温2-4小时后，停止加热，冷却，降温至80℃以下，打开出料阀，过滤生成物，得到滤饼和母液，洗涤滤饼后，真空干燥，得到磷酸铁锰锂粉末；
(5)将步骤(4)得到的磷酸铁锰锂粉末与碳源混匀，在惰性气体保护下，700℃焙烧4小时，得到碳包覆的磷酸铁锰锂。
进一步的，步骤(3)中加入物质的摩尔比为Li:M(Fe+Mn):P＝3.0:1.0:1.0；加料完毕后铁锰元素的合量浓度为0.3-0.5mol/L。
进一步的，将步骤(4)中过滤的母液以及洗涤滤饼的洗水合并，蒸发浓缩后，回收磷酸锂。
进一步的，步骤(4)中洗涤后滤饼在110-120℃真空干燥12小时。
进一步的，所述硫酸亚铁和硫酸锰为硫酸亚铁和硫酸锰的成品晶体或结晶前的液体；所述磷酸锂为氢氧化锂和磷酸中和得来的，或由母液回收得来的。
进一步的，磷酸铁锰锂粉末与碳源按照100:(15-20)的质量比混匀。
进一步的，所述碳源为葡萄糖。
相比于现有技术，本发明具有以下有益效果：
(1)本发明的纳米磷酸铁锰锂的水热合成方法，采用高温混合反应原料，创造了真正的分子级混合的反应起始条件，制得的材料颗粒均匀，形貌由普通水热产物的片状转向类球状，三维尺度均可达到纳米级别，有利于锂离子扩散路径的缩短，有利于电极材料加成极片后正极活性物质颗粒间的接触，从根本上有利于提高材料的电化学性能及延长循环寿命。
(2)本发明的纳米磷酸铁锰锂的水热合成方法，通过控制反应原料的温度，改变晶核生成的数量，最终实现颗粒大小的控制，得到均匀的纳米级产物颗粒，且工艺条件温和、易操作。
(3)采用本发明的水热合成方法得到的纳米磷酸铁锰锂，用于锂离子电池正极材料，制备得到的锂离子电池具有高倍率放电性能，同时低温放电性能也得到有效提高。
附图说明
为了更清楚的说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单的介绍，显而易见的，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它附图。
图1为本发明实施例1制备得到的磷酸铁锰锂的形貌图；
图2为本发明对比例1制备得到的磷酸铁锰锂的形貌图；
图3为本发明实施例1制备得到的电池的25℃，0.2C充放电曲线图。
具体实施方式
下面将结合本发明中的实施例，对本发明实施例中的技术方案进行清楚、完整的描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通的技术人员在没有做出创造性劳动的前提下所获得的所有其它实施例，都属于本发明的保护范围。
实施例1
一种纳米磷酸铁锰锂的水热合成方法，包括以下步骤：
第一步：水热合成反应
(1)将6mol一水氢氧化锂溶于水，使溶液的体积为2L，加入高压釜1中，在搅拌下加入2mol磷酸约0.15L，加完后，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，搅拌下从室温加热至150℃，保温备用，得到料浆A；
(2)将1mol七水硫酸亚铁和1mol二水硫酸锰用水溶解，并稀释至2L，加入高压釜2中，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，加热至150℃，保温备用，得到料浆B；
(3)将高压釜3加热到150℃，打开进料阀和安全排气阀，向高压釜3中并流加入料浆A和料浆B，同时强力搅拌，维持150℃反应2小时；加入物质的摩尔比为：Li：M(Fe+Mn)：P＝3.0：1.0：1.0；加料完毕后，溶液中铁锰元素的合量浓度约为0.5mol/L；
第二步：生成物的过滤、洗涤和干燥
(4)上述反应完成后，高压釜通过盘管用冷却油冷却至80℃，打开放空阀和出料阀，过滤生成物，得到滤饼和母液，洗涤滤饼三次，滤饼于120℃真空烘干至恒重，得到LiFe 0.5Mn 0.5PO 4粉白色粉体；母液并洗水入回收罐，蒸发结晶后回收磷酸锂。
第三步：碳包覆处理
将第二步制备得到的粉白色粉体与葡萄糖按质量比100:15混合，在700℃、氮气保护下煅烧4小时，得到碳包覆的磷酸铁锰锂(LiFe 0.5Mn 0.5PO 4/C)产品。
将以上制备得到的磷酸铁锰锂/碳作为电池正极材料，测试其充放电性能。具体的：将上面得到的磷酸铁锰锂/碳、乙炔黑、60％聚四氟乙烯乳液按质量比7∶2∶1的比例混合，碾压成厚度为0.10～0.15㎜的片，并与铝箔压合在一起，于120℃真空干燥12小时，制得电池正极。以金属锂片负极、1M的LiPF 6溶液为电解液、cell gard 2300为隔膜，与上述正极组装成扣式电池，在25℃以0.2C、1C倍率进行充放电，再于-20℃以0.2C放电，充放电的电压范围为4.5～2.3V。其测试结果如表1及图3所示。
本实施例制得的产品的形貌，如图1所示，可见材料的颗粒均匀、形貌为类球状，且三维尺度达到纳米级别，有利于锂离子扩散路径的缩短，有利于电极材料加工成极片后正极活性物质颗粒间的接触。
实施例2
将实施例1中的料浆A中的磷酸锂以母液回收的磷酸锂代替，其他制备步骤同实施例1。
其电化学性能测试结果如表1所示。
实施例3
将实施例1中的料浆A、料浆B和最终水热合成反应温度均设为140℃，反应时间设为4小时，其他制备步骤同实施例1。
其电化学性能测试结果如表1所示。
对比例1
按常规加料技术进行水热合成反应，所有的反应原料液起始温度均是室温。
将6mol一水氢氧化锂溶于水，使溶液的体积为2L，在搅拌下加入2mol磷酸约0.15L，得到磷酸锂浆料，此为料浆A。
将1mol七水硫酸亚铁和1mol二水硫酸锰用水溶解，并稀释至2L，得到料浆B。
将料浆A加入10L的高压反应釜，用惰性气体吹扫釜内死体积中的空气后，在强力搅拌下加入料浆B，加料完毕后，密闭反应釜。设定升温速度为4℃/min，反应温度150℃，反应时间2小时。其它步骤同实施例1。
电化学性能测试结果见表1。
本对比例制得的产品的形貌，如图2所示。反应原料在常温条件下混合，之后的升温过程中，在尚未达到设定的反应温度时即已开始反应，首先生成中间产物-沉淀形态的磷酸锂和蓝铁矿磷酸铁锰，在接近120℃时，中间产物开始溶解并生成目标产物磷酸铁锰锂，从120℃升至150℃经历约10分钟(中间有一段因溶解吸热出现的温度停滞现象)，成核离子要靠中间产物的溶解来释放，因此，成核离子不足，产物的颗粒就比较大。可以预见，如果反应釜的体积变大，例如由10L变为1M 3，反应釜的体积放大了100倍，理论上其传热表面积只放大了21倍，造成反应器扩大后产生负面效应，表现为升温速度更慢，使得反应体系在低温段停留时间更长，低温段形成的磷酸铁锰锂不仅在材料晶体结构上存在离子错排问题，而且产物的颗粒均匀性差，颗粒尺寸更大，性能更加恶化，而事实上，生产型的反应釜往往都是更大型的，即使可以增加盘管以增 大传热面积，仍无法避免放大负效应。
表1电化学性能测试结果
  0.2C比容量/mAhg -1 1C比容量/mAhg -1 -20℃下0.2C比容量/mAhg -1
实施例1 159.7 149.1 132.1
实施例2 159.6 148.5 131.8
实施例3 158.9 147.7 129.7
对比例1 148.5 138.8 114.6
由表1及图3结果可见，高温加料方式，创造了反应原料之间分子级混合的条件，并且在这种条件下，瞬间产生大量晶核，反应体系中存在大量的自由态的构晶离子，从而扭转了以前的技术中存在的固体前驱体导致的构晶离子不足状态。同时本发明中，晶体的择向生长趋势被晶体快速生长所取代，大量晶核快速生长，最终产物的颗粒细小，球形度高，有利于电极压实密度的提高及电化学容量的发挥。由实施例和对比例数据可见，在本发明的优化条件下，磷酸铁锰锂材料表现出极佳的电化学性能。同时本发明的制备方法简单、经济，工艺条件温和、易操作，解决了常规技术中的设备放大负效应，适合工业化大生产应用。
以上借助具体实施例对本发明做了进一步描述，但是应该理解的是，这里具体的描述，不应理解为对本发明的实质和范围的限定，本领域内的普通技术人员在阅读本说明书后对上述实施例做出的各种修改，都属于本发明所保护的范围。

Claims (7)

  1. 一种纳米磷酸铁锰锂的水热合成方法，其特征在于，包括以下步骤：
    (1)将磷酸锂和水混合后加入高压釜1中，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，搅拌下从室温加热至140-150℃，保温备用，得到料浆A；
    (2)将硫酸亚铁和硫酸锰用水溶解，加入高压釜2中，用惰性气体吹扫釜内死体积中的空气后，密封高压釜，加热至140-150℃，保温备用，得到料浆B；
    (3)将高压釜3加热到140-150℃，打开进料阀和安全排气阀，向高压釜3中并流加入料浆A和料浆B，搅拌，维持140-150℃反应2-4小时；
    (4)在140-150℃下保温2-4小时后，停止加热，冷却，降温至80℃以下，打开出料阀，过滤生成物，得到滤饼和母液，洗涤滤饼后，真空干燥，得到磷酸铁锰锂粉末；
    (5)将步骤(4)得到的磷酸铁锰锂粉末与碳源混匀，在惰性气体保护下，700℃焙烧4小时，得到碳包覆的磷酸铁锰锂。
  2. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，步骤(3)中加入物质的摩尔比为Li:M(Fe+Mn):P＝3.0:1.0:1.0；加料完毕后铁锰元素的合量浓度为0.3-0.5mol/L。
  3. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，将步骤(4)中过滤的母液以及洗涤滤饼的洗水合并，蒸发浓缩后，回收磷酸锂。
  4. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，所述硫酸亚铁和硫酸锰为硫酸亚铁和硫酸锰的成品晶体或结晶前的液体。
  5. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，所述磷酸锂为氢氧化锂和磷酸中和得来的，或由母液回收得来的。
  6. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，步骤(5)中磷酸铁锰锂粉末与碳源按照100：(15-20)的质量比混匀。
  7. 根据权利要求1所述的纳米磷酸铁锰锂的水热合成方法，其特征在于，所述碳源为葡萄糖。
PCT/CN2022/110407 2022-04-12 2022-08-05 一种纳米磷酸铁锰锂的水热合成方法 WO2023197483A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP22937121.6A EP4393875A1 (en) 2022-04-12 2022-08-05 Hydrothermal synthesis method for nano lithium manganese iron phosphate

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210381172.2A CN114644329B (zh) 2022-04-12 2022-04-12 一种纳米磷酸铁锰锂的水热合成方法
CN202210381172.2 2022-04-12

Publications (1)

Publication Number Publication Date
WO2023197483A1 true WO2023197483A1 (zh) 2023-10-19

Family

ID=81997508

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/110407 WO2023197483A1 (zh) 2022-04-12 2022-08-05 一种纳米磷酸铁锰锂的水热合成方法

Country Status (3)

Country Link
EP (1) EP4393875A1 (zh)
CN (1) CN114644329B (zh)
WO (1) WO2023197483A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114644329B (zh) * 2022-04-12 2023-07-07 深圳市沃伦特新能源有限公司 一种纳米磷酸铁锰锂的水热合成方法
CN115385385A (zh) * 2022-09-26 2022-11-25 江苏沙英喜实业有限公司 一种锂电池用锂锰铁复合盐及其生产工艺和应用

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102249208A (zh) * 2011-05-06 2011-11-23 朱鸥鹭 一种锂离子电池正极材料磷酸锰铁锂的水热合成方法
CN102569800A (zh) * 2012-02-01 2012-07-11 大连理工大学 超临界水热过程制备锂离子电池正极材料磷酸铁锂的方法
CN103762362A (zh) * 2014-01-27 2014-04-30 厦门钨业股份有限公司 一种纳米磷酸锰铁锂正极材料的水热制备方法
CN104583130A (zh) 2013-01-10 2015-04-29 株式会社Lg化学 磷酸铁锂纳米粉末的制备方法
CN104918888A (zh) 2013-01-10 2015-09-16 株式会社Lg化学 用于制备磷酸铁锂纳米粉末的方法
CN105060266A (zh) * 2015-07-20 2015-11-18 河北工业大学 一种纳米磷酸铁锂的水热合成方法
JP5890886B1 (ja) * 2014-10-22 2016-03-22 太平洋セメント株式会社 リン酸マンガン鉄リチウム正極活物質及びその製造方法
CN105470468A (zh) * 2015-12-30 2016-04-06 山东精工电子科技有限公司 一种氟掺杂磷酸铁锰锂正极材料及其制备方法
CN111777051A (zh) 2020-07-03 2020-10-16 南京理工大学 一种片状的磷酸铁锂电极材料的制备方法
CN112125292A (zh) * 2020-08-14 2020-12-25 中国科学院金属研究所 一种磷酸锰铁锂的水热合成方法
CN113871596A (zh) * 2021-09-27 2021-12-31 湖南亿普腾科技有限公司 锂复合材料、锂离子电池正极材料制备方法及锂离子电池
CN114644329A (zh) * 2022-04-12 2022-06-21 深圳沃伦特新能源科技有限公司 一种纳米磷酸铁锰锂的水热合成方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100570930C (zh) * 2005-09-16 2009-12-16 上海电力学院 磷酸铁锂的制备方法
CN102671577B (zh) * 2011-08-30 2015-10-14 中国科学院宁波材料技术与工程研究所 无机纳米粒子合成用水热反应装置
CN103035909B (zh) * 2011-09-29 2015-07-22 比亚迪股份有限公司 磷酸亚铁锂前躯体、磷酸亚铁锂材料和磷酸亚铁锂/碳复合材料的制备方法
CN104752720B (zh) * 2013-12-30 2017-12-01 比亚迪股份有限公司 一种磷酸锰铁锂及其制备方法和应用
KR20160080243A (ko) * 2014-12-29 2016-07-07 주식회사 엘지화학 리튬철-망간인산화물 제조 방법 및 이로부터 제조된 올리빈형 리튬철-망간인산화물
CN104681795B (zh) * 2015-01-29 2017-11-14 北大先行科技产业有限公司 一种磷酸铁锰锂/碳复合材料的制备方法
CN104934601B (zh) * 2015-06-15 2017-08-04 北京石油化工学院 一种磷酸锰铁锂正极材料的制备方法
CN105036103B (zh) * 2015-08-03 2017-08-01 山东威能环保电源科技股份有限公司 一种长方体型锂电池正极材料磷酸铁锰锂的制备方法

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102249208A (zh) * 2011-05-06 2011-11-23 朱鸥鹭 一种锂离子电池正极材料磷酸锰铁锂的水热合成方法
CN102569800A (zh) * 2012-02-01 2012-07-11 大连理工大学 超临界水热过程制备锂离子电池正极材料磷酸铁锂的方法
CN104583130A (zh) 2013-01-10 2015-04-29 株式会社Lg化学 磷酸铁锂纳米粉末的制备方法
CN104582878A (zh) 2013-01-10 2015-04-29 株式会社Lg化学 磷酸铁锂纳米粉末的制备方法
CN104918888A (zh) 2013-01-10 2015-09-16 株式会社Lg化学 用于制备磷酸铁锂纳米粉末的方法
CN103762362A (zh) * 2014-01-27 2014-04-30 厦门钨业股份有限公司 一种纳米磷酸锰铁锂正极材料的水热制备方法
JP5890886B1 (ja) * 2014-10-22 2016-03-22 太平洋セメント株式会社 リン酸マンガン鉄リチウム正極活物質及びその製造方法
CN105060266A (zh) * 2015-07-20 2015-11-18 河北工业大学 一种纳米磷酸铁锂的水热合成方法
CN105470468A (zh) * 2015-12-30 2016-04-06 山东精工电子科技有限公司 一种氟掺杂磷酸铁锰锂正极材料及其制备方法
CN111777051A (zh) 2020-07-03 2020-10-16 南京理工大学 一种片状的磷酸铁锂电极材料的制备方法
CN112125292A (zh) * 2020-08-14 2020-12-25 中国科学院金属研究所 一种磷酸锰铁锂的水热合成方法
CN113871596A (zh) * 2021-09-27 2021-12-31 湖南亿普腾科技有限公司 锂复合材料、锂离子电池正极材料制备方法及锂离子电池
CN114644329A (zh) * 2022-04-12 2022-06-21 深圳沃伦特新能源科技有限公司 一种纳米磷酸铁锰锂的水热合成方法

Also Published As

Publication number Publication date
EP4393875A1 (en) 2024-07-03
CN114644329A (zh) 2022-06-21
CN114644329B (zh) 2023-07-07

Similar Documents

Publication Publication Date Title
US11345609B2 (en) High voltage lithium nickel cobalt manganese oxide precursor, method for making the same, and high voltage lithium nickel cobalt manganese oxide cathode material
WO2023197483A1 (zh) 一种纳米磷酸铁锰锂的水热合成方法
CN110048118B (zh) 一种高镍型镍钴锰酸锂单晶前驱体及其制备方法和高镍型镍钴锰酸锂单晶正极材料
CN101752564B (zh) 一维纳米结构的锂离子电池正极材料磷酸铁锂的水热合成法
CN112028126B (zh) 一种小粒径补锂添加剂Li5FeO4的制备方法和应用
CN113871596B (zh) 锂复合材料、锂离子电池正极材料制备方法及锂离子电池
CN114348984A (zh) 一种利用钛白副产制备纳米磷酸铁、纳米磷酸亚铁的方法
WO2024060549A1 (zh) 一种连续化制备磷酸铁的方法和应用
GB2621302A (en) Nanometer sheet-like iron phosphate, preparation method therefor and use thereof
WO2022151977A1 (zh) 纳米钴酸锂正极材料的制备方法及其应用
CN108511724B (zh) 一种溶胶凝胶辅助超临界co2干燥制备磷酸锰铁锂方法
WO2023142677A1 (zh) 掺杂型磷酸铁及其制备方法和应用
CN111244447B (zh) 一种片状二水磷酸铁及其制备方法
CN114628660A (zh) 一种磷酸铁锰锂纳米颗粒的水热合成方法
WO2022237393A1 (zh) 磷酸铁锂的制备方法
CN116730317A (zh) 一种磷酸铁锂的制备方法
CN105060266B (zh) 一种纳米磷酸铁锂的水热合成方法
CN113213545B (zh) 一种球形碳酸铁锰及其制备方法
CN116902943A (zh) 一种可调控比表面的磷酸铁的制备方法
WO2023020063A1 (zh) 一种三元前驱体的制备方法
CN115974036A (zh) 一种球形磷酸铁锰锂纳米颗粒及其制备方法
WO2024036906A1 (zh) 一种锂离子电池正极材料及其制备方法
CN115448382A (zh) 一种高镍三元前驱体及其制备方法和应用
CN105680044A (zh) 一种水热法等摩尔制备磷酸铁锂的方法
CN113526531A (zh) 从锂电三元材料洗液中回收高纯亚微米级碳酸锂的方法

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: 22937121

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2022937121

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2022937121

Country of ref document: EP

Effective date: 20240328