CN118054014A - Lithium iron manganese phosphate and preparation method and application thereof - Google Patents

Lithium iron manganese phosphate and preparation method and application thereof Download PDF

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CN118054014A
CN118054014A CN202410445306.1A CN202410445306A CN118054014A CN 118054014 A CN118054014 A CN 118054014A CN 202410445306 A CN202410445306 A CN 202410445306A CN 118054014 A CN118054014 A CN 118054014A
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manganese
iron
solution
lithium
rich
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CN118054014B (en
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朱武
凌仕刚
靳佳
李文强
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Tianjin Guoan Mengguli New Material Technology Co ltd
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Tianjin Guoan Mengguli New Material Technology Co ltd
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Abstract

The invention belongs to the field of lithium ion batteries. The invention provides a lithium iron manganese phosphate and a preparation method and application thereof, wherein the lithium iron manganese phosphate comprises a core, the content gradient of manganese element is reduced, the content gradient of iron element is increased, the content gradient of phosphorus element is increased, and the outer surface of the core is a lithium-rich phosphate protective layer; the lithium iron manganese phosphate also includes a carbon layer coating the inner core. The invention reduces the crystallinity of the material by forming manganese, iron and phosphorus with gradient distribution, so that the material can grow faster to effectively improve the compaction density. The phosphorus element is excessive on the outer surface of the inner core to form a lithium phosphate-rich protective layer, and the lithium phosphate-rich protective layer can not only improve the conductivity, but also effectively improve the problem of manganese dissolution, so that the capacity and the cycle performance of the lithium manganese iron phosphate can be improved.

Description

Lithium iron manganese phosphate and preparation method and application thereof
Technical Field
The invention belongs to the field of lithium ion batteries, and relates to lithium iron manganese phosphate and a preparation method and application thereof.
Background
With the increasing severity of global energy crisis and environmental problems, the development of new energy has become a focus of attention in various countries. The lithium ion battery is used as an efficient and environment-friendly energy storage device and is widely applied to the fields of electric automobiles, electric bicycles, energy storage systems and the like. With the continuous expansion of new energy markets, the demand of lithium ion batteries has shown a trend of explosive growth.
In lithium ion batteries, the positive electrode material is one of the determining factors for the performance of lithium ion batteries. At present, common lithium ion battery anode materials mainly comprise lithium cobaltate, lithium manganate, nickel cobalt manganese ternary materials, lithium iron phosphate and the like. These materials have advantages and disadvantages, such as lithium cobaltate has higher energy density and voltage plateau, but has higher cost and poorer safety; the lithium manganate has lower cost and better safety, but has lower energy density and voltage platform; the nickel-cobalt-manganese ternary material combines the advantages of the nickel-cobalt-manganese ternary material and the nickel-cobalt-manganese ternary material, but the cost is still high.
The lithium iron phosphate anode material has the advantages of low cost, high safety, long service life and the like, and can better meet the requirements of new energy automobile markets on high safety and low cost of lithium ion batteries. However, lithium iron phosphate also has some disadvantages such as low tap density, low electron conductivity, etc., which limit its application in high energy density lithium ion batteries.
The lithium iron manganese phosphate, which is a novel material for further development of lithium iron phosphate, combines the advantages of manganese and iron, and is expected to improve the disadvantages of the lithium iron phosphate material. However, in the current research and application process, lithium iron manganese phosphate still has the problems of low compaction density and capacity and compaction are not compatible, and the potential advantage of high energy density is not exhibited. Meanwhile, due to the high manganese content, the material has the problem of manganese dissolution, thereby causing capacity attenuation and cycle performance reduction. Therefore, how to ensure the capacity, the compaction density of the lithium iron manganese phosphate is improved, and the lithium iron manganese phosphate can have excellent cycle performance, and becomes a key point of research.
Disclosure of Invention
In view of the problems existing in the prior art, the invention aims to provide a lithium iron manganese phosphate, a preparation method and application thereof, wherein the lithium iron manganese phosphate has high compaction density and simultaneously has excellent capacity and cycle performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides lithium iron manganese phosphate, which comprises an inner core, wherein the content of manganese element is reduced in a gradient manner from the center of the inner core to the outer surface of the inner core, the content of iron element is increased in a gradient manner, the content of phosphorus element is gradually increased, and the outer surface of the inner core is a lithium phosphate-rich protective layer; the lithium iron manganese phosphate also includes a carbon layer coating the inner core.
The invention forms the inner core with gradient distribution of manganese, iron and phosphorus, so that the phosphorus is excessive on the outer surface of the inner core. The non-stoichiometric phosphorus-rich design can reduce the crystallinity of the material, so that the material can grow unevenly more quickly, and the size particles are mixed so as to effectively improve the compaction density. The design of surface iron-rich can play a role in inhibiting Mn dissolution and improving circulation stability. In addition, excessive phosphorus forms a lithium-rich phosphate protective layer on the outer surface of the inner core, and the lithium-rich phosphate protective layer can not only improve conductivity, but also effectively improve the problem of manganese dissolution, so that the capacity and the cycle performance of lithium manganese iron phosphate can be improved.
The following technical scheme is a preferred technical scheme of the invention, but is not a limitation of the technical scheme provided by the invention, and the technical purpose and beneficial effects of the invention can be better achieved and realized through the following technical scheme.
As a preferable technical scheme of the invention, the chemical formula of the inner core comprises Li yMnxFe1-x(PO4)z, wherein x is 0.4-0.9, for example, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9 and the like; y is 1.02 to 1.1, and may be, for example, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, or the like; z is 1.03 to 1.1, and may be, for example, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, or 1.09, etc., but is not limited to the values recited above, and other values not recited in the above-mentioned numerical ranges are equally applicable.
Preferably, the minimum content of manganese element in the core is 85% -96% of the maximum content, for example 85%, 87%, 89%, 91%, 93%, 94% or 96%, etc., but not limited to the recited values, and other non-recited values in the above range are equally applicable.
Preferably, the highest content of phosphorus element in the core is 105% -130% of the lowest content, for example 105%, 108%, 110%, 114%, 116%, 118%, 120%, 122%, 124%, 126%, 128% or 130%, etc., but not limited to the recited values, and other non-recited values in the above range are equally applicable.
It should be noted that the values of x, y and z in Li yMnxFe1-x(PO4)z represent the macroscopic chemical general formula of all lithium iron manganese phosphate synthesized in the core, for example, in the lithium iron manganese phosphate material of the core, the actual value of z may be greater than 1.1 at one place and may be less than 1.03 at another place, but the total content of phosphorus is such that the value of z should be 1.03-1.1 when all lithium iron manganese phosphate materials of the whole core are synthesized. The value of z is 1.03-1.1, which indicates that the lithium iron manganese phosphate material is rich in phosphorus. Therefore, in the core, the highest content of the phosphorus element can be 105% -130% of the lowest content, and is not limited to 107% represented by the ratio of 1.1 to 1.03.
The particle diameter of the core is preferably 50 to 1000nm, for example, 50nm, 80nm, 100nm, 200nm, 300nm, 500nm, 600nm, 700nm, 800nm, 900nm or 1000nm, but the particle diameter is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned range are applicable.
Preferably, the inner core is a single crystal material, has an olivine structure, and belongs to Pmnb orthorhombic systems.
Preferably, the lithium phosphate-rich protective layer comprises 0.1% -3.5% by mass of the core, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4% or 3.5%, preferably 0.5% -3.2%, more preferably 0.5% -0.7%, but is not limited to the recited values, and other non-recited values within the above-recited ranges are equally applicable.
Preferably, the thickness of the lithium phosphate-rich protective layer is 1 to 5nm, for example, 1nm, 1.3nm, 1.5nm, 1.8nm, 2nm, 2.2nm, 2.5nm, 2.8nm, 3nm, 3.3nm, 3.5nm, 3.7nm, 3.9nm, 4nm, 4.3nm, 4.5nm, 4.7nm or 5nm, etc., and is not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.
Preferably, the carbon layer accounts for 0.8% -2.5% of the mass of the lithium manganese iron phosphate, for example, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.1%, 2.3% or 2.5%, etc., but is not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.
The D50 particle size of the lithium manganese iron phosphate is preferably 0.3 to 2. Mu.m, for example, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm or 2 μm, etc., but is not limited to the recited values, and other values not recited in the above-mentioned numerical ranges are equally applicable.
Preferably, the lithium manganese iron phosphate further contains a doping element comprising at least one of Zr, mg, ti, nb, V, mo, co or Ni, such as a typical but non-limiting combination including Zr and Mg, ti and Nb, V and Mo, or Co and Ni, etc.
Preferably, the doping element occupies 500 to 10000ppm by mass of the lithium manganese iron phosphate, for example, 500ppm, 800ppm, 1000ppm, 2000ppm, 5000ppm, 7000ppm, 8000ppm, 9000ppm, 10000ppm, or the like, but is not limited to the recited values, and other non-recited values within the above-mentioned numerical ranges are equally applicable.
In a second aspect, the present invention provides a method for preparing lithium iron manganese phosphate according to the first aspect, the method comprising:
the method comprises the steps of enabling a manganese source, an iron source, a phosphorus source, an oxidant and a precipitator to perform coprecipitation reaction in a solution, gradually reducing the concentration of the manganese source in the solution in the coprecipitation reaction process, and gradually increasing the concentration of the iron source and the phosphorus source in the solution at the same time to obtain a precursor;
mixing the precursor, lithium salt and a first carbon source, and performing first sintering to obtain a sintered material;
And mixing the primary sintering material with a second carbon source, and performing secondary sintering to obtain the lithium iron manganese phosphate.
The preparation method comprises the steps of firstly controlling the real-time dosage and concentration of a manganese source, an iron source and a phosphorus source in a coprecipitation reaction to obtain a precursor with the gradient distribution design of manganese, iron and phosphorus; the precursor is mixed with lithium salt and a first carbon source and then subjected to carbothermic reduction to generate an inner core with gradient distribution of manganese, iron and phosphorus, wherein the outer surface of the inner core is rich in phosphorus and excessive in phosphorus to generate a lithium phosphate-rich protective layer; the gradient distribution structure in the precursor causes rapid material growth, so that the compaction density is effectively improved; the invention does not need to be further crushed, avoids crushing and damaging a coated carbon layer, protects a surface structure, and effectively reduces the specific surface area, thereby improving the capacity and the cycle performance of the formed lithium manganese iron phosphate.
The lithium-rich phosphate protective layer does not contain manganese or iron, i.e., the lithium-rich phosphate layer is not composed of a pure phase of lithium phosphate, and the gradient of the present invention is designed such that phosphorus is present in an excessive amount on the outer surface layer, and the excessive phosphorus naturally combines with the excessive lithium to form lithium phosphate in the carbothermic reduction method, thereby forming the lithium-rich phosphate layer.
As a preferable technical scheme of the invention, the preparation method comprises the following steps:
Preparing a manganese source and an iron source into a manganese-rich and iron-poor solution and an iron-rich and manganese-poor solution; preparing a phosphorus source solution, an oxidant solution and a precipitator solution respectively from a phosphorus source, an oxidant and a precipitator;
and (3) co-current flowing the manganese-rich and iron-poor solution, the iron-rich and manganese-poor solution, the phosphorus source solution, the oxidant solution and the precipitator solution, performing a coprecipitation reaction, gradually reducing the co-current flow speed of the manganese-rich and iron-poor solution, and gradually increasing the co-current flow speed of the iron-rich and manganese-poor solution and the phosphorus source solution to obtain the precursor.
The precursor can be prepared by using separate manganese source solution and iron source solution in combination. The invention adopts the manganese-rich and iron-rich solution and the iron-rich and manganese-rich solution to be matched for use, and the mixing uniformity is better.
Preferably, the molar ratio of manganese to iron in the manganese-rich iron-depleted solution is (3-5): 1, such as 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, or 5:1, but not limited to the recited values, and other non-recited values within the above range are equally applicable.
Preferably, the molar ratio of manganese to iron in the iron-rich and manganese-poor solution is 1 (1-3), for example, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, or 1:3, etc., but not limited to the recited values, and other non-recited values within the above range are equally applicable.
Preferably, the total molar concentration of manganese and iron in the manganese-rich and iron-rich lean solution is the same as1 to 3mol/L, for example, 1mol/L, 1.2mol/L, 1.4mol/L, 1.6mol/L, 1.8mol/L, 2mol/L, 2.2mol/L, 2.4mol/L, 2.6mol/L, 2.8mol/L, or 3mol/L, etc., but not limited to the above values, and other non-enumerated values within the above numerical range are equally applicable.
Preferably, the sum of the real-time co-current velocity of the manganese-rich and iron-lean solution and the real-time co-current velocity of the iron-rich and manganese-lean solution is equal to the initial co-current velocity of the manganese-rich and iron-lean solution.
Preferably, the initial parallel flow velocity of the manganese-rich and iron-lean solution is 1 to 3L/h, for example, 1L/h, 1.2L/h, 1.4L/h, 1.6L/h, 1.8L/h, 2L/h, 2.2L/h, 2.4L/h, 2.6L/h, 2.8L/h or 3L/h, etc., and the initial parallel flow velocity of the manganese-rich and iron-lean solution is 0L/h, but is not limited to the listed values, and other values not listed in the above numerical ranges are equally applicable.
Preferably, the parallel flow speed of the manganese-rich and iron-lean solution is reduced by 0.2 to 0.6L/h, for example, 0.2L/h, 0.3L/h, 0.4L/h, 0.5L/h or 0.6L/h, etc., but the present invention is not limited to the recited values, and other non-recited values within the above-recited ranges are equally applicable.
Preferably, the parallel flow speed of the phosphorus source solution is increased by 0.05 to 0.1L/h, for example, 0.05L/h, 0.06L/h, 0.07L/h, 0.08L/h, 0.09L/h, or 0.1L/h, etc., but the present invention is not limited to the above-mentioned values, and other non-mentioned values within the above-mentioned values are equally applicable.
Preferably, the molar concentration of the phosphorus source in the phosphorus source solution is the same as the total molar concentration of manganese and iron in the manganese-rich iron-depleted solution; the parallel flow rate of the phosphorus source solution is 0.9 to 1.2 times, for example, 0.9 times, 0.94 times, 0.97 times, 1 times, 1.03 times, 1.05 times, 1.08 times, 1.1 times, or 1.2 times, the initial parallel flow rate of the manganese-rich iron-depleted solution, but is not limited to the recited values, and other values not recited in the above-mentioned numerical ranges are equally applicable.
Preferably, the molar concentration of oxidant in the oxidant solution is the same as the total molar concentration of manganese and iron in the manganese-rich iron-depleted solution; the co-current velocity of the oxidant solution is 1 to 1.4 times, for example, 1 time, 1.05 time, 1.1 time, 1.15 time, 1.2 time, 1.25 time, 1.3 time, 1.35 time, or 1.4 time, the initial co-current velocity of the manganese-rich iron-depleted solution, etc., but is not limited to the recited values, and other non-recited values within the above-recited ranges are equally applicable.
Preferably, the molar concentration of precipitant in the precipitant solution is the same as the total molar concentration of manganese and iron in the manganese-rich iron-depleted solution; the co-current flow rate of the precipitant solution is controlled to adjust the pH of the co-precipitation reaction.
In a preferred embodiment of the present invention, the pH of the coprecipitation reaction is 3 to 7, for example, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7, but the pH is not limited to the values listed, and other values not listed in the above-mentioned numerical ranges are equally applicable.
The temperature of the coprecipitation reaction is preferably 40 to 85 ℃, for example, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 85 ℃ or the like, but the coprecipitation reaction is not limited to the values listed, and other values not listed in the above-mentioned value ranges are applicable.
Preferably, the time of the coprecipitation reaction is 6 to 10 hours, for example, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but the present invention is not limited to the listed values, and other non-listed values in the above-mentioned range are applicable.
Preferably, the oxidant comprises hydrogen peroxide and/or ammonium persulfate.
Preferably, the precipitant comprises aqueous ammonia.
Preferably, the manganese source and the iron source include sulfate or sulfite of corresponding metal elements.
Preferably, the phosphorus source comprises at least one of phosphoric acid, monoammonium phosphate, or monoammonium phosphate.
As a preferred embodiment of the present invention, the method of mixing the precursor with the lithium salt and the first carbon source comprises sequentially grinding and spray drying.
Preferably, the precursor, the lithium salt and the first carbon source are ground in a liquid phase, and the grinding solvent is water.
Preferably, the grinding comprises sanding and/or ball milling.
The particle size obtained by the above-mentioned grinding is preferably 0.2 to 0.5. Mu.m, for example, 0.2. Mu.m, 0.25. Mu.m, 0.3. Mu.m, 0.35. Mu.m, 0.4. Mu.m, 0.45. Mu.m, or 0.5. Mu.m, etc., but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned numerical ranges are equally applicable.
Preferably, the inlet air temperature of the spray drying is 150 to 200 ℃, such as 150 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃, 190 ℃, 195 ℃, 200 ℃, or the like, and the outlet air temperature is 90 to 110 ℃, such as 90 ℃, 95 ℃, 100 ℃,105 ℃, or 110 ℃, or the like, but the spray drying is not limited to the recited values, and other values not recited in the above-mentioned ranges are equally applicable.
Preferably, the precursor and the lithium salt are used in an amount of 1:1.02, 1:1.04, 1:1.06, 1:1.08, or 1:1.1, etc. in accordance with the ratio of the total molar amount of iron and manganese to the molar amount of lithium being 1 (1.02 to 1.1), but the present invention is not limited to the recited values, and other non-recited values within the above-recited ranges are equally applicable.
Preferably, the amount of the first carbon source is controlled to be 5% -10% of the total mass of the precursor and the lithium salt, for example, 5%, 6%, 7%, 8%, 9% or 10%, etc., but the present invention is not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.
As a preferred technical scheme of the present invention, the preparation method further includes mixing a dopant with the precursor, the lithium salt and the first carbon source simultaneously;
The amount of the dopant is preferably controlled to be 500 to 10000ppm, for example, 500ppm, 800ppm, 1000ppm, 2000ppm, 5000ppm, 7000ppm, 8000ppm, 9000ppm or 10000ppm, etc., but is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value ranges are equally applicable.
Preferably, the dopant comprises an oxide and/or hydroxide corresponding to at least one doping element of Zr, mg, ti, nb, V, mo, co or Ni.
Preferably, the lithium salt comprises lithium hydroxide and/or lithium carbonate.
Preferably, the first carbon source comprises at least one of glucose, vitamin C, citric acid, or carbon nanotubes, such as typical but non-limiting examples of combinations include glucose in combination with vitamin C, glucose in combination with citric acid, glucose in combination with carbon nanotubes, vitamin C in combination with citric acid, and the like.
Preferably, the temperature of the first sintering is 600 to 700 ℃, for example 600 ℃, 610 ℃, 620 ℃, 630 ℃, 640 ℃, 650 ℃, 660 ℃, 670 ℃, 680 ℃, 690 ℃, 700 ℃ or the like, and the time is 4 to 8 hours, for example 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours or the like, but not limited to the recited values, and other non-recited values within the above-recited value range are equally applicable.
Preferably, the first sintering is performed under a protective atmosphere.
As a preferred technical scheme of the present invention, the primary combustion material is crushed before being mixed with the second carbon source.
Preferably, the method of crushing comprises jet milling and/or grinding.
Preferably, the particle size obtained by the crushing is 0.5 to 2.5 μm, for example, 0.5 μm, 0.8 μm,1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm or 2.5 μm, etc., but not limited to the values listed, and other values not listed in the above-mentioned numerical ranges are equally applicable.
The invention preferably controls the crushing granularity of the primary sintered material, and the excessive granularity can cause easy material dropping of pole pieces of the positive electrode material when rolling, and simultaneously causes lower compaction density of the pole pieces; too small particle size can cause too large specific surface area, and the material is easy to absorb water, so that the processability of the slurry is affected.
Preferably, the method for mixing the first sintered material and the second carbon source comprises the steps of preparing a second carbon source solution, mixing the first sintered material and the second carbon source solution, performing filter pressing to obtain a filter pressing material, and performing the second sintering on the filter pressing material.
In the preparation method of the invention, if the secondary carbon source coating is not carried out, the product has larger specific surface, low compaction, poor slurry processability and poor cycle performance. The preparation method of the invention preferably mixes the burned-in material and the second carbon source in a special mode, namely, the burned-in material and the second carbon source are mixed in a liquid phase system through pressure filtration, and secondary carbon coating is realized, which is beneficial to reducing the specific surface area of the material and further beneficial to improving the capacity and the cycle performance. Compared with the prior art, such as spray drying, for coating the second carbon source, the coating uniformity is not as good as that of the filter pressing mixing process, and in the existing scheme of spray drying, the second carbon source needs to be further crushed after the second sintering, so that the process cost is high, and the surface structure of the product can be damaged.
Preferably, the mass concentration of the second carbon source in the second carbon source solution is 40% -60%, for example 40%, 44%, 48%, 50%, 52%, 55%, 58% or 60%, etc., but not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.
Preferably, the water content of the press filter is 3 to 5wt%, for example, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, or 5wt%, etc., but the press filter is not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.
Preferably, in the filter press material, the second carbon source is 2% -8% of the mass of the burned-in material, for example, 2%, 3%, 4%, 5%, 6%, 7% or 8%, but not limited to the listed values, and other non-listed values in the above-mentioned range are equally applicable.
Preferably, the temperature of the second sintering is 650 to 750 ℃, for example, 650 ℃, 660 ℃, 670 ℃, 680 ℃, 690 ℃, 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, or the like, but the second sintering is not limited to the values listed, and other values not listed in the above-mentioned value ranges are equally applicable.
Preferably, the second carbon source comprises at least one of polyethylene glycol (PEG), polyvinyl alcohol (PVA), or polyvinylpyrrolidone (PVP), such as typical but non-limiting combinations comprising PEG in combination with PVA, PEG in combination with PVP, or PVP in combination with PVA, and the like.
In a third aspect, the invention provides a positive electrode plate, which contains the lithium iron manganese phosphate according to the second aspect.
In a fourth aspect, the invention provides a lithium ion battery, which contains the positive electrode plate in the third aspect.
Compared with the prior art, the invention has at least the following beneficial effects:
According to the invention, the crystallization degree of the material is reduced by forming the inner core with gradient distribution of manganese, iron and phosphorus, so that the material can grow more quickly to effectively improve the compaction density. The phosphorus elements in the inner core are sequentially raised from inside to outside, and a lithium phosphate-rich protective layer is formed on the outer surface of the inner core, so that the conductivity of the lithium phosphate-rich protective layer can be improved, the problem of manganese dissolution can be effectively solved, and the capacity and the cycle performance of lithium manganese iron phosphate can be further improved.
According to the preparation method, the primary combustion material and the second carbon source are mixed and carbon coating is realized by carrying out filter pressing in a liquid phase system, the coating amount of the secondary carbon source is controlled according to the concentration of the secondary carbon source solution and the residual moisture amount of the obtained filter pressing material, the morphology of the primary combustion material is kept, the moisture is controlled, the specific surface area of the material is reduced, and the capacity and the cycle performance are further improved.
Drawings
FIGS. 1 and 2 are SEM test charts of lithium manganese iron phosphate obtained in example 1 and comparative example 1, respectively;
FIG. 3 is a graph showing the compaction density test of lithium iron manganese phosphate obtained in example 1 and comparative example 1;
FIG. 4 is a graph showing charge-discharge curve test of lithium manganese iron phosphate obtained in example 1 and comparative example 1;
fig. 5 is a graph showing the IC capacity cycle curve test of lithium iron manganese phosphate obtained in example 1 and comparative example 1.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments.
It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides lithium manganese iron phosphate, which comprises an inner core with the particle size of 180-260 nm, wherein the content of manganese element is reduced in a gradient manner from the center of the inner core to the outer surface of the inner core, the lowest content of manganese element accounts for 50% of the highest content, the content of iron element is increased in a gradient manner, the content of phosphorus element is gradually increased, the highest content of phosphorus element is 121% of the lowest content, and the outer surface of the inner core is a lithium-rich phosphate protective layer; the lithium iron manganese phosphate also comprises a carbon layer coating the inner core; the lithium phosphate-rich protective layer accounts for 1.6% of the mass of the inner core; the carbon layer accounts for 1.8% of the mass of the lithium manganese iron phosphate; the lithium iron manganese phosphate also contains a doping element Ti, wherein the doping element accounts for 3000ppm of the mass of the lithium iron manganese phosphate; the D50 particle size of the lithium iron manganese phosphate is 0.8-1.6 mu m.
The embodiment also provides a preparation method of the lithium manganese iron phosphate, which comprises the following steps:
(1) Ferrous sulfate is used as an iron source, manganous sulfate is used as a manganese source, phosphoric acid is used as a phosphorus source, hydrogen peroxide is used as an oxidant, and ammonia water is used as a precipitator; preparing a manganese source and an iron source into 10L of a manganese-rich and iron-poor solution with a molar ratio of manganese to iron of 4:1 and 10L of an iron-rich and manganese-poor solution with a molar ratio of manganese to iron of 1:1.5, wherein the total molar concentration of manganese and iron in the manganese-rich and iron-poor solution is the same as that in the iron-rich and manganese-poor solution and is 2mol/L; preparing a phosphorus source, an oxidant and a precipitator into a 10.5L phosphorus source solution, a 12L oxidant solution and a precipitator solution with the concentration of 2mol/L respectively;
Feeding the manganese-rich and iron-poor solution into a reaction kettle at an initial parallel flow speed of 2L/h, and gradually reducing the real-time parallel flow speed at a speed of 0.4L/h; simultaneously, pumping the iron-rich and manganese-poor solution into a reaction kettle at an initial parallel flow speed of 0L/h, and gradually increasing the real-time parallel flow speed at a speed of 0.4L/h; simultaneously, the phosphorus source solution is injected into a reaction kettle at an initial parallel flow speed of 1.9L/h, and the real-time parallel flow speed is gradually increased at a speed of 0.08L/h until the real-time parallel flow speed is constant after 2.3L/h; simultaneously pumping the oxidant solution into a reaction kettle at a constant parallel flow speed of 2.4L/h, simultaneously pumping the precipitator solution into the reaction kettle, controlling the real-time parallel flow speed of the precipitator solution to enable the pH value of a reaction system to be 5, controlling the temperature of the reaction kettle to be 60 ℃, stopping feeding after 5h of feeding, and continuing coprecipitation reaction for 3h to obtain a precursor;
(2) Lithium carbonate is used as lithium salt, magnesium oxide is used as doping agent, and glucose is used as first carbon source; mixing the precursor, lithium salt, a doping agent and a first carbon source, and controlling the dosage of the precursor and the lithium salt according to the ratio of the total molar quantity of iron and manganese to the molar quantity of lithium being 1:1.02; controlling the dosage of the first carbon source according to 8% of the total mass of the precursor and the lithium salt; controlling the dosage of the dopant according to the doping amount of 3000 ppm; sequentially performing sand grinding and spray drying, controlling the granularity obtained by sand grinding to be 0.35 mu m, controlling the air inlet temperature of spray drying to be 170 ℃ and the air outlet temperature to be 100 ℃ to obtain a spray drying material, and performing first sintering on the spray drying material at 650 ℃ for 6 hours under nitrogen atmosphere to obtain a sintered material;
(3) And (3) carrying out jet milling on the primary sintered material to obtain a crushed material with the granularity of 0.8 mu m, mixing the crushed material with a second carbon source solution, wherein the second carbon source solution is a polyethylene glycol solution with the mass fraction of 50%, stirring for 15min, and then carrying out filter pressing to obtain a filter pressing material with the water content of 4%, wherein the second carbon source in the filter pressing material is 5% of the mass of the primary sintered material, and carrying out second sintering on the filter pressing material at the temperature of 700 ℃ to obtain the lithium manganese iron phosphate.
Example 2
The present embodiment provides a lithium iron manganese phosphate, which is prepared by adjusting the rate of gradually decreasing the solution rich in manganese and poor in iron and the rate of gradually increasing the solution rich in iron and poor in manganese from 0.4L/h to 0.1L/h in the step (2), except that the other conditions are exactly the same as in the embodiment 1.
Example 3
The present embodiment provides a lithium iron manganese phosphate, which is prepared by adjusting the rate of gradually decreasing the solution rich in manganese and poor in iron and the rate of gradually increasing the solution rich in iron and poor in manganese from 0.4L/h to 0.2L/h in the step (2), except that the other conditions are exactly the same as in the embodiment 1.
Example 4
The present embodiment provides a lithium iron manganese phosphate, which is prepared by adjusting the speed of gradually decreasing the solution rich in manganese and poor in iron and the speed of gradually increasing the solution rich in iron and poor in manganese from 0.4L/h to 0.6L/h in the step (2), wherein the speed of adding the solution rich in manganese and poor in iron is decreased to 0L/h, and the speed of increasing the concentration of the solution rich in iron and poor in manganese to 2L/h is kept unchanged, except that the other conditions are exactly the same as in the embodiment 1.
Example 5
The present embodiment provides a lithium iron manganese phosphate, which is prepared by adjusting the gradually decreasing speed of the solution rich in manganese and poor in iron and the gradually increasing speed of the solution rich in iron and poor in manganese from 0.4L/h to 0.7L/h in the step (2), wherein the adding speed of the solution rich in manganese and poor in iron is decreased to 0L/h, and the speed is kept unchanged after the concentration of the solution rich in iron and poor in manganese is gradually increased to 2L/h, except that the other conditions are exactly the same as in the embodiment 1.
Example 6
This example provides a lithium iron manganese phosphate which is prepared in the same manner as in example 1, except that no dopant is used in step (2).
Example 7
The embodiment provides a lithium manganese iron phosphate, which is prepared by performing jet milling on the primary sintered material to obtain a crushed material with the granularity of 0.8 μm, mixing the crushed material with a second carbon source solution, wherein the second carbon source solution is a polyethylene glycol solution with the mass fraction of 50%, controlling the mass fraction of the second carbon source to be 5% of that of the primary sintered material, performing spray drying after stirring and mixing, and performing secondary sintering at 700 ℃ to obtain the lithium manganese iron phosphate. Other conditions were exactly the same as in example 1 except for this.
Comparative example 1
The comparative example provides a lithium iron manganese phosphate, which is prepared by feeding a manganese-rich and manganese-poor solution into a reaction kettle at an initial parallel flow rate of 2L/h in the step (2) of the preparation method, and keeping the real-time parallel flow rate unchanged at 2L/h, without feeding the manganese-rich and manganese-poor solution, except that the conditions are exactly the same as in example 1.
Comparative example 2
The comparative example provides a lithium iron manganese phosphate, which is prepared by feeding an iron-rich and manganese-poor solution into a reaction kettle at an initial parallel flow rate of 2L/h in the step (2) of the preparation method, and keeping the real-time parallel flow rate unchanged at 2L/h, without feeding the manganese-rich and manganese-poor solution, except that the conditions are exactly the same as in example 1.
Comparative example 3
This comparative embodiment provides a method for preparing lithium manganese iron phosphate. In step (2) of the preparation method, both the rich manganese and poor iron solution and the rich iron and poor manganese solution are injected into the reaction vessel at an initial co flow rate of 1L/h, and the real-time co flow rate is kept constant at 1L/h. Other conditions are completely the same as in embodiment 1.
Comparative example 4
The comparative example provides a lithium iron manganese phosphate, which is prepared by the process of (2) feeding a phosphorus source solution into a reaction vessel at an initial parallel flow rate of 1.9L/h, and maintaining the real-time parallel flow rate at 1.9L/h, except that the conditions are exactly the same as in example 1.
Comparative example 5
The comparative example provides a lithium iron manganese phosphate, which is prepared by the process of (2) feeding a phosphorus source solution into a reaction vessel at an initial parallel flow rate of 2.3L/h, and maintaining the real-time parallel flow rate at 2.3L/h, except that the conditions are exactly the same as in example 1.
Comparative example 6
The comparative example provides a lithium iron manganese phosphate, the preparation method does not carry out the step (3), and the primary combustion material obtained in the step (2) is directly used as the lithium iron manganese phosphate.
In the lithium iron manganese phosphate material obtained in the above, the chemical formula of the lithium iron manganese phosphate obtained in the example 1 is Li 1.02Mn0.6Fe0.4(PO4)1.05 chemical formula, and the gradient distribution of manganese, iron and phosphorus elements is uniform; the chemical formula of the lithium iron manganese phosphate obtained in the embodiment 2 is Li 1.02Mn0.75Fe0.25(PO4)1.05, and the gradient distribution of manganese, iron and phosphorus elements is uniform; the chemical formula of the lithium iron manganese phosphate obtained in the embodiment 3 is Li 1.02Mn0.7Fe0.3(PO4)1.05 chemical formula, and the gradient distribution of manganese, iron and phosphorus elements is graded; the chemical formulas of the lithium iron manganese phosphate obtained in examples 4 and 5 are Li 1.02Mn0.6Fe0.4(PO4)1.05 chemical formulas, but the first stage of coprecipitation is gradient uniform doping, and the later stage is pure Li 1.02Mn0.4Fe0.6(PO4)1.05 without gradient; the chemical formula of the lithium iron manganese phosphate obtained in the comparative example 1 is Li 1.02Mn0.8Fe0.2(PO4)1.05, and manganese and iron are distributed in a non-gradient manner; the chemical formula of the lithium iron manganese phosphate obtained in the comparative example 2 is Li 1.02Mn0.4Fe0.6(PO4)1.05, and manganese and iron are distributed in a non-gradient manner; the chemical formula of the lithium iron manganese phosphate obtained in the comparative example 3 is Li 1.02Mn0.6Fe0.4(PO4)1.05;, the comparative example 4 is a uniform phosphorus-lean material with non-gradient distribution of phosphorus, and the comparative example 5 is a uniform phosphorus-rich material with non-gradient distribution of phosphorus.
Characterization and testing:
I, morphology: fig. 1 and 2 are SEM test charts of lithium manganese iron phosphate obtained in example 1 and comparative example 1, respectively, and it can be seen from the figures that the particles obtained in example 1 are significantly increased because the gradient material of the element gradient is not formed in comparative example 1, the elements are uniformly distributed from the inside to the surface, the reactivity is poor, and the particle growth is suppressed.
II. Conductivity and compaction Density: the tests were carried out using a kinetic PRCD1100 powder resistivity & compaction densitometer, experimental methods: firstly, thickness background subtraction is carried out, then 0.3g of sample is weighed and added into a sample bin, and single-point experiment is carried out: the continuous spot test was performed by test methods of 1000kg, 2000kg, 3000kg, 3500kg, to test conductivity and compaction at different pressures.
Fig. 3 shows the results of the compaction density tests of the lithium iron manganese phosphate obtained in example 1 and comparative example 1, and it can be seen from the figure that the compaction of the material obtained in example 1 is greater, because the material growth is greater in example 1, and the grain size distribution is better, so that the compaction of the material is improved.
Table 1 shows the conductivity test results of lithium manganese iron phosphate obtained in example 1 and comparative example 1, and it can be seen from table 1 that the powder conductivity of the material obtained in example 1 is improved by two orders of magnitude compared with comparative example 1, because the coating layer of lithium phosphate is formed on the surface of example 1, and the conductivity of the material is improved.
III, testing the battery performance: taking the lithium iron manganese phosphate obtained in the examples and the comparative examples as a positive electrode material, adding NMP to adjust the solid content of the slurry to 35% according to the mass ratio of the lithium iron manganese phosphate to the SP to the PVDF=90:5:5, compacting the pole piece to 2.30g/cm 3 with the surface density of 8mg/cm 2, testing by using a blue charging and discharging device, testing the pole piece with a testing system of 2.0-4.35V, carrying out constant-current constant-voltage charging at the first circle of 0.1C, and then carrying out constant-current discharging at the 0.1C to 2.0V under the cutoff condition that the current is less than or equal to 0.02C; the second circle of 1C constant-current constant-voltage charging is carried out, the cut-off condition is that the current is less than or equal to 0.02C, and then the 1C constant-current discharging is carried out until the current reaches 2.0V; the second work cycle was repeated 100 times, and the results are shown in Table 2.
Fig. 4 and 5 are respectively a charge-discharge curve test chart and an IC capacity cycle curve test chart of lithium iron manganese phosphate obtained in example 1 and comparative example 1, and it can be seen from the combination of table 1 that the specific discharge capacity of example 0.1C is 4.8mAh/g higher than that of comparative example, the capacity of 1C is 6.5mAh/g higher, the cycle retention rate is 1.7% higher, the capacity retention rate of 1C/0.1C is 1.7% higher, the constant current charging ratio is 1.8% higher, which indicates that the capacity and rate performance of the example are better, and the lithium phosphate coating layer formed by surface phosphorus enrichment improves the intrinsic conductivity of the material, improves the capacity and rate, simultaneously protects the surface interface of the material and improves the cycle performance.
From the above, it can be seen that the present invention allows the phosphorus to be in excess at the outer surface of the core by forming the core with a gradient distribution of manganese, iron and phosphorus. The non-stoichiometric phosphorus-rich design can reduce the crystallinity of the material, so that the material can grow unevenly more quickly, and the size particles are mixed so as to effectively improve the compaction density. The design of surface iron-rich can play a role in inhibiting Mn dissolution and improving circulation stability. In addition, excessive phosphorus forms a lithium-rich phosphate protective layer on the outer surface of the inner core, and the lithium-rich phosphate protective layer can not only improve conductivity, but also effectively improve the problem of manganese dissolution, so that the capacity and the cycle performance of lithium manganese iron phosphate can be improved.
The detailed process equipment and process flow of the present invention are described by the above embodiments, but the present invention is not limited to, i.e., it does not mean that the present invention must be practiced depending on the detailed process equipment and process flow. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims (10)

1. The lithium iron manganese phosphate is characterized by comprising a core, wherein the content of manganese element is reduced in a gradient manner from the center of the core to the outer surface of the core, the content of iron element is increased in a gradient manner, the content of phosphorus element is gradually increased, and the outer surface of the core is a lithium phosphate-rich protective layer; the lithium iron manganese phosphate also includes a carbon layer coating the inner core.
2. The lithium iron manganese phosphate according to claim 1, wherein the chemical formula of the inner core includes Li yMnxFe1-x(PO4)z, wherein x is 0.4 to 0.9; y is 1.02-1.1; z is 1.03-1.1; in the inner core, the lowest content of manganese element accounts for 85% -96% of the highest content; the highest content of the phosphorus element is 105% -130% of the lowest content.
3. The lithium iron manganese phosphate according to claim 1, wherein the particle size of the core is 50-1000 nm; the lithium phosphate-rich protective layer accounts for 0.1% -3.5% of the mass of the inner core; the thickness of the lithium phosphate-rich protective layer is 1-5 nm; the carbon layer accounts for 0.8% -2.5% of the mass of the lithium manganese iron phosphate; the D50 particle size of the lithium iron manganese phosphate is 0.3-2 mu m.
4. The lithium manganese iron phosphate according to claim 1, further comprising a doping element comprising at least one of Zr, mg, ti, nb, V, mo, co or Ni; the doping element accounts for 500-10000 ppm of the mass of the lithium manganese iron phosphate.
5. A method of preparing the lithium iron manganese phosphate according to any one of claims 1 to 4, comprising:
the method comprises the steps of enabling a manganese source, an iron source, a phosphorus source, an oxidant and a precipitator to perform coprecipitation reaction in a solution, gradually reducing the concentration of the manganese source in the solution in the coprecipitation reaction process, and gradually increasing the concentration of the iron source and the phosphorus source in the solution at the same time to obtain a precursor;
mixing the precursor, lithium salt and a first carbon source, and performing first sintering to obtain a sintered material;
And mixing the primary sintering material with a second carbon source, and performing secondary sintering to obtain the lithium iron manganese phosphate.
6. The method for preparing lithium iron manganese phosphate according to claim 5, comprising:
Preparing a manganese source and an iron source into a manganese-rich and iron-poor solution and an iron-rich and manganese-poor solution; preparing a phosphorus source solution, an oxidant solution and a precipitator solution respectively from a phosphorus source, an oxidant and a precipitator;
Cocurrent flow of a manganese-rich and iron-poor solution, an iron-rich and manganese-poor solution, a phosphorus source solution, an oxidant solution and a precipitator solution is carried out to carry out coprecipitation reaction, and simultaneously the cocurrent flow speed of the manganese-rich and iron-poor solution is gradually reduced, and the cocurrent flow speed of the iron-rich and manganese-poor solution and the phosphorus source solution is gradually increased to obtain a precursor;
Wherein the molar ratio of manganese to iron in the manganese-rich and iron-poor solution is (3-5): 1; the molar ratio of manganese to iron in the iron-rich and manganese-poor solution is 1 (1-3); the total molar concentration of manganese and iron in the manganese-rich and iron-poor solution is the same as that of the manganese-rich and iron-poor solution and is 1-3 mol/L; the molar concentration of the phosphorus source in the phosphorus source solution is the same as the total molar concentration of manganese and iron in the manganese-rich and iron-poor solution; the molar concentration of the oxidant in the oxidant solution is the same as the total molar concentration of manganese and iron in the manganese-rich and iron-poor solution; the molar concentration of the precipitant in the precipitant solution is the same as the total molar concentration of manganese and iron in the manganese-rich and iron-poor solution;
The sum of the real-time co-current velocity of the manganese-rich and iron-lean solution and the real-time co-current velocity of the iron-rich and manganese-lean solution is equal to the initial co-current velocity of the manganese-rich and iron-lean solution; the initial parallel flow speed of the manganese-rich and iron-poor solution is 1-3L/h, and the initial parallel flow speed of the iron-rich and manganese-poor solution is 0L/h; the parallel flow speed of the manganese-rich and iron-poor solution is reduced according to the speed of 0.2-0.6L/h; the parallel flow speed of the phosphorus source solution is increased according to the speed of 0.05-0.1L/h; the parallel flow speed of the phosphorus source solution is 0.9-1.2 times of the initial parallel flow speed of the manganese-rich and iron-poor solution; the parallel flow speed of the oxidant solution is 1-1.4 times of the initial parallel flow speed of the manganese-rich and iron-poor solution; the co-current flow rate of the precipitant solution is controlled to adjust the pH of the co-precipitation reaction.
7. The method for preparing lithium iron manganese phosphate according to claim 5, wherein,
Controlling the usage amount of the precursor and the lithium salt according to the ratio of the total molar amount of iron and manganese to the molar amount of lithium of 1 (1.02-1.1); controlling the dosage of the first carbon source according to 5% -10% of the total mass of the precursor and the lithium salt;
The pH of the coprecipitation reaction is 3-7; the temperature of the coprecipitation reaction is 40-85 ℃; the time of the coprecipitation reaction is 6-10 hours; the temperature of the first sintering is 600-700 ℃ and the time is 4-8 hours; and the first sintering is performed under a protective atmosphere; the temperature of the second sintering is 650-750 ℃;
The oxidant comprises hydrogen peroxide and/or ammonium persulfate; the precipitant comprises ammonia water; the manganese source and the iron source comprise sulfate or sulfite of corresponding metal elements; the phosphorus source comprises at least one of phosphoric acid, monoammonium phosphate or monoammonium phosphate; the lithium salt comprises lithium hydroxide and/or lithium carbonate; the first carbon source comprises at least one of glucose, vitamin C, citric acid or carbon nanotubes; the second carbon source comprises at least one of polyethylene glycol, polyvinyl alcohol, or polyvinylpyrrolidone.
8. The method of preparing lithium iron manganese phosphate according to claim 5, further comprising mixing the precursor with a lithium salt and a first carbon source, comprising sequentially milling and spray drying; the grinding comprises sanding and/or ball milling; the granularity obtained by grinding is 0.2-0.5 mu m; the air inlet temperature of the spray drying is 150-200 ℃, and the air outlet temperature is 90-110 ℃;
The preparation method further comprises the steps of mixing a doping agent, the precursor, lithium salt and a first carbon source simultaneously; controlling the dosage of the dopant according to the doping amount of 500-10000 ppm; the dopant comprises an oxide and/or a hydroxide corresponding to at least one doping element of Zr, mg, ti, nb, V, mo, co or Ni;
The preparation method further comprises the steps of crushing the first burning material before mixing the first burning material with the second carbon source; the crushing method comprises jet milling and/or grinding; the granularity obtained by crushing is 0.5-2.5 mu m;
The preparation method further comprises the steps of preparing a second carbon source solution, mixing a first burning material with the second carbon source solution, performing filter pressing to obtain a filter pressing material, and performing the second sintering on the filter pressing material; the mass concentration of the second carbon source in the second carbon source solution is 40% -60%; the water content of the filter pressing material is 3-5wt%; in the filter pressing material, the second carbon source accounts for 2% -8% of the mass of the primary combustion material.
9. A positive electrode sheet, characterized in that it contains the lithium iron manganese phosphate according to any one of claims 1 to 4.
10. A lithium ion battery comprising the positive electrode sheet of claim 9.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113871596A (en) * 2021-09-27 2021-12-31 湖南亿普腾科技有限公司 Lithium composite material, preparation method of lithium ion battery cathode material and lithium ion battery
CN114512649A (en) * 2022-02-08 2022-05-17 江苏中兴派能电池有限公司 Composite lithium manganese iron phosphate cathode material, preparation method and application thereof
CN116081588A (en) * 2021-11-05 2023-05-09 松山湖材料实验室 Positive electrode active material precursor and preparation method thereof, positive electrode active material and preparation method thereof, positive electrode and lithium ion secondary battery
WO2023231245A1 (en) * 2022-06-02 2023-12-07 深圳市德方纳米科技股份有限公司 Multi-element phosphate positive electrode material and preparation method therefor, and secondary battery
CN117497749A (en) * 2023-11-02 2024-02-02 湖北融通高科先进材料集团股份有限公司 Carbon-coated lithium iron manganese phosphate material, preparation method and application thereof
CN117832421A (en) * 2023-11-17 2024-04-05 宜都兴发化工有限公司 Single-core multi-shell lithium iron manganese phosphate composite positive electrode material and preparation method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113871596A (en) * 2021-09-27 2021-12-31 湖南亿普腾科技有限公司 Lithium composite material, preparation method of lithium ion battery cathode material and lithium ion battery
CN116081588A (en) * 2021-11-05 2023-05-09 松山湖材料实验室 Positive electrode active material precursor and preparation method thereof, positive electrode active material and preparation method thereof, positive electrode and lithium ion secondary battery
CN114512649A (en) * 2022-02-08 2022-05-17 江苏中兴派能电池有限公司 Composite lithium manganese iron phosphate cathode material, preparation method and application thereof
WO2023231245A1 (en) * 2022-06-02 2023-12-07 深圳市德方纳米科技股份有限公司 Multi-element phosphate positive electrode material and preparation method therefor, and secondary battery
CN117497749A (en) * 2023-11-02 2024-02-02 湖北融通高科先进材料集团股份有限公司 Carbon-coated lithium iron manganese phosphate material, preparation method and application thereof
CN117832421A (en) * 2023-11-17 2024-04-05 宜都兴发化工有限公司 Single-core multi-shell lithium iron manganese phosphate composite positive electrode material and preparation method thereof

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