CN116332147A - Lithium manganese iron phosphate positive electrode material, preparation method and application thereof, and lithium ion battery - Google Patents

Lithium manganese iron phosphate positive electrode material, preparation method and application thereof, and lithium ion battery Download PDF

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CN116332147A
CN116332147A CN202310323104.5A CN202310323104A CN116332147A CN 116332147 A CN116332147 A CN 116332147A CN 202310323104 A CN202310323104 A CN 202310323104A CN 116332147 A CN116332147 A CN 116332147A
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manganese
lithium
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phosphate
phosphoric acid
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张应朝
熊德宇
夏冬炎
李妍竹
陈明
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Guizhou Anda Technology Energy Co ltd
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    • H01—ELECTRIC ELEMENTS
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Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a lithium manganese iron phosphate anode material, a preparation method and application thereof and a lithium ion battery. The preparation method comprises the following steps: (1) Reacting the slurry or solution containing the manganese source with phosphoric acid solution, and performing post-treatment to obtain a manganous phosphate precursor; (2) And mixing the manganous phosphate precursor with ferric phosphate, a lithium source, a carbon source and a doped metal source, and sequentially performing sanding, spray drying and sintering to obtain the lithium manganese phosphate anode material. The method has the characteristics of simple equipment and process, good atomic economy, low environmental pressure and low manufacturing cost, can effectively improve the charge-discharge specific capacity of the lithium iron manganese phosphate anode material, reduces manganese dissolution, has the advantages of environmental protection, green and pollution-free properties and recycling, and is suitable for industrial production.

Description

Lithium manganese iron phosphate positive electrode material, preparation method and application thereof, and lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a lithium manganese iron phosphate positive electrode material, a preparation method and application thereof and a lithium ion battery.
Background
Along with the exhaustion of energy and the requirement of environmental protection, the lithium ion battery is widely used as a clean and green battery, and the positive electrode material of the lithium ion battery is used for limiting the wide application of the lithium ion battery in the aspect of power. Currently, the positive electrode material of the power battery mainly comprises ternary lithium and lithium iron phosphate. Ternary lithium has high capacity density, but has poor safety, and the raw materials used contain expensive metal nickel and cobalt, so the cost is high. The lithium iron phosphate has the advantages of good safety, environmental friendliness, good multiplying power charge-discharge characteristics, good circulation stability, abundant and cheap raw materials and the like, but has a lower discharge voltage platform (3.4V), thereby influencing the energy density exertion. The lithium manganese phosphate is similar to the lithium iron phosphate, has an olivine structure, has a theoretical gram capacity of approximately 170mAh/g, has a higher discharge voltage plateau (4.1V), has an energy density which can be theoretically 20% higher than that of the lithium iron phosphate, but has Mn in the charge and discharge process 3+ The Jahn-Teller effect of (C) causes distortion of the lattice, mn 3+ And the dissolution of lithium ions and the lower lithium ion diffusion rate and electron conductivity, thereby making the electric performance not effectively exhibited. The manganese in a certain proportion in the lithium manganese phosphate is changed into iron to form the lithium manganese iron phosphate, and then the electric performance of the lithium manganese iron phosphate can be released and Mn can be inhibited by means of carbon coating, nanocrystallization, metal ion doping and the like 3+ Is dissolved in the solvent. Compared with the liquid phase method, the solid phase method has simple flow, mild reaction conditions, environmental protection and easy industrialization.
Disclosure of Invention
The invention aims to solve the problems of low lithium ion diffusion rate, low electron conductivity and low manganese dissolution of a lithium iron phosphate positive electrode material in the prior art, and provides a lithium iron phosphate positive electrode material, a preparation method and application thereof, and a lithium ion battery.
The inventor finds that the manganese phosphate precursor is prepared by adopting the environment-friendly, pollution-free and recyclable reaction of phosphoric acid and a manganese source, the post-treatment steps are few, the environment is protected, and the reacted filtrate can be recycled. The phosphoric acid is directly used as a phosphorus source, so that the introduction of impurity ions (such as sodium ions and ammonium ions) is avoided, the environmental protection pressure and the cost are reduced, and the phosphoric acid in the filtrate can be recovered through concentration and is recycled.
In order to achieve the above object, a first aspect of the present invention provides a method for preparing a lithium iron manganese phosphate positive electrode material, the method comprising the steps of:
(1) Reacting the slurry or solution containing the manganese source with phosphoric acid solution, and performing post-treatment to obtain a manganous phosphate precursor;
(2) And mixing the manganous phosphate precursor with ferric phosphate, a lithium source, a carbon source and a doped metal source, and sequentially performing sanding, spray drying and sintering to obtain the lithium manganese phosphate anode material.
The second aspect of the invention provides a lithium iron manganese phosphate anode material prepared by the preparation method of the first aspect.
The third aspect of the invention provides an application of the lithium iron manganese phosphate anode material in the technical field of lithium ion batteries.
According to a fourth aspect of the invention, there is provided a lithium ion battery comprising the positive electrode, the negative electrode, the separator and the electrolyte made of the positive electrode material of lithium manganese iron phosphate according to the second aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) The preparation method of the lithium iron manganese phosphate anode material provided by the invention has the advantages that the required equipment and the process are simple, the charge-discharge specific capacity of the lithium iron manganese phosphate anode material can be effectively improved, and the manganese dissolution is reduced;
(2) The method uses the cheap manganese source and the environment-friendly, pollution-free and recyclable phosphorus source to prepare the manganous phosphate precursor, has the advantages of thorough reaction, high atomic utilization rate, low environmental pressure and low manufacturing cost, and is suitable for industrial production;
(3) The lithium iron manganese phosphate anode material provided by the invention has the advantages of good carbon coating effect and high charge and discharge capacity.
Drawings
FIG. 1 is an SEM image of a manganous phosphate precursor of example 1;
fig. 2 is an SEM image of the lithium iron manganese phosphate cathode material in example 1.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the present invention, unless otherwise indicated, the weights of lithium iron phosphate, manganese source, phosphorus source, lithium source, carbon source and doped metal source are all on a dry basis; the term "gram specific capacity" is used to refer to the total amount of electricity that can be discharged per unit mass of the battery active material, and the larger the value thereof, the larger the amount of electricity that the battery material can store.
The first aspect of the invention provides a preparation method of a lithium iron manganese phosphate anode material, which comprises the following steps:
(1) Reacting the slurry or solution containing the manganese source with phosphoric acid solution, and performing post-treatment to obtain a manganous phosphate precursor;
(2) And mixing the manganous phosphate precursor with ferric phosphate, a lithium source, a carbon source and a doped metal source, and sequentially performing sanding, spray drying and sintering to obtain the lithium manganese phosphate anode material.
In the invention, a solid phase method is adopted, and the electrochemical performances such as conductivity, multiplying power performance, energy density and the like of the lithium manganese iron phosphate anode material are improved by a technical means of combining element doping, carbon coating and nanocrystallization, and the preparation method has the advantages that the required equipment and process are simple, the charge-discharge specific capacity of the lithium manganese iron phosphate anode material can be effectively improved, and the manganese dissolution is reduced; the invention prepares the manganous phosphate precursor by using a cheap manganese source and an environment-friendly, pollution-free and recyclable phosphorus source, has the advantages of thorough reaction, high atomic utilization rate, low environmental pressure and low manufacturing cost, and is suitable for industrial production.
The mixing mode of the manganese source-containing slurry or solution and the phosphoric acid solution in the step (1) is not particularly limited, and according to a preferred embodiment of the present invention, the manganese source-containing slurry or solution is added to the phosphoric acid solution to react or the phosphoric acid solution is added to the manganese source-containing slurry or solution to react; preferably, the phosphoric acid solution is added to the slurry or solution containing the manganese source for the reaction. By adopting the embodiment, the manganous phosphate precursor with finer particle size can be obtained.
According to a preferred embodiment of the present invention, in step (1), the reaction conditions include: stirring speed is 100-1000r/min; the addition time is 30-60min. By adopting the embodiment, the reaction degree of the manganese source and phosphoric acid can be effectively improved, so that the utilization rate of atoms is improved, and the manufacturing cost is reduced.
According to a particularly preferred embodiment of the present invention, in step (1), the reaction conditions include: the stirring speed is 800-1000r/min; the adding time is 30-40min. By adopting the embodiment, the reaction degree of the manganese source and the phosphoric acid can be further improved, so that the utilization rate of atoms is improved, and the manufacturing cost is reduced.
The mode of the post-treatment in the step (1) is not particularly limited in the present invention, and is a conventional operation known to those skilled in the art. According to a preferred embodiment of the invention, the post-treatment comprises filter pressing, washing, drying, removal of crystal water. By adopting the embodiment, the manganous phosphate precursor with high purity can be obtained.
According to a preferred embodiment of the invention, in step (1), the manganese source is calculated as divalent manganese ion and the phosphoric acid is calculated as phosphate, the molar ratio of said manganese source to said phosphoric acid being 1 (1-1.1), preferably 1 (1.02-1.05).
According to a preferred embodiment of the invention, in step (1), the mass concentration of the manganese source-containing slurry or solution is 30-60%, preferably 40-50%.
According to a preferred embodiment of the invention, in step (1), the phosphoric acid solution has a mass concentration of 10-50%, preferably 20-40%.
According to a preferred embodiment of the present invention, in step (2), the manganous phosphate precursor is expressed as divalent manganese ion and the iron phosphate is expressed as iron ion, and the molar ratio of the manganous phosphate precursor to the iron phosphate is (1-5): 1, preferably (2-3): 1.
According to a preferred embodiment of the invention, in step (2), the phosphorus source is calculated as the total phosphorus ions in the manganese phosphate and the iron phosphate, and the molar ratio of the lithium source to the phosphorus source is (1-1.1): 1, preferably (1.01-1.05): 1, calculated as lithium ions.
According to a preferred embodiment of the present invention, in step (2), the carbon source is 5 to 15%, preferably 8 to 13% by mass based on 100% by mass of the total mass of the manganous phosphate precursor, the iron phosphate and the lithium source.
According to a preferred embodiment of the present invention, in step (2), the doped metal source has a mass of 0.01 to 1%, preferably 0.1 to 0.5%, based on 100% of the total mass of the manganous phosphate precursor, the iron source and the lithium source.
According to a preferred embodiment of the present invention, in step (2), the manganous phosphate precursor is mixed with iron phosphate, lithium source, carbon source and doped metal source and then sanded to a D50 of 300-500nm, D90 of 600-900nm, preferably to a D50 of 300-400nm, D90 of 600-700nm. By adopting the embodiment, the nanoscale lithium iron manganese phosphate anode material can be obtained.
The conditions for the sanding in the step (2) are not particularly limited as long as the aforementioned particle size range can be achieved. According to a preferred embodiment of the present invention, the sanding conditions include: the temperature is 10-60 ℃; the time is 5-20h. Preferably, the temperature is 20-30 ℃; the time is 10-15h.
The conditions for the spray-drying in the step (2) are not particularly limited in the present invention, and are conventional operations known to those skilled in the art. According to a preferred embodiment of the present invention, the spray drying conditions include: the feeding speed of the feeding pump is 30-100L/h; the temperature of the air inlet of the spray is 100-250 ℃; the temperature of the air outlet of the spray is 80-120 ℃.
According to a particularly preferred embodiment of the invention, the spray drying conditions comprise: the feeding speed of the feeding pump is 50-70L/h; the temperature of an air inlet of the spray is 150-200 ℃; the temperature of the air outlet of the spray is 90-110 ℃.
According to a preferred embodiment of the present invention, in step (2), the sintering conditions include: the temperature is 400-800 ℃; the time is 10-20h. Preferably, the temperature is 500-750 ℃; the time is 10-15h. According to the embodiment, the carbon source is cracked in the nitrogen atmosphere at a certain temperature to form carbon coated on the surfaces of the lithium manganese iron phosphate particles, so that on one hand, the lithium manganese iron phosphate particles can be prevented from growing excessively, and on the other hand, the conductivity of the lithium manganese iron phosphate positive electrode material can be improved, and therefore the electrical property of a battery assembled by taking the lithium manganese iron phosphate positive electrode material as a positive electrode is improved.
The sintering mode in the step (2) is not particularly limited, and according to a particularly preferred embodiment of the present invention, the sintering is performed for 3-10 hours by heating to 400-600 ℃ under a protective atmosphere, and then is performed for 7-10 hours by heating to 650-800 ℃.
The kind of the protective gas is not particularly limited in the present invention, and according to a preferred embodiment of the present invention, the protective gas is at least one of nitrogen, helium, neon, argon, krypton, xenon, and radon, preferably nitrogen.
The kind of the manganese source is not particularly limited in the present invention, and according to a preferred embodiment of the present invention, the manganese source is selected from at least one of manganese oxide, manganese carbonate, manganese acetate, manganese hydroxide and manganese citrate, preferably at least one of manganese carbonate, manganese acetate and manganese citrate, more preferably manganese carbonate. By adopting the embodiment, the byproducts of the reaction of the manganese source and the phosphoric acid are water, carbon dioxide and acid, so that the post-treatment is convenient, the pollution to the environment is reduced and the manufacturing cost is reduced through concentration, recovery and reutilization.
According to a preferred embodiment of the present invention, the lithium source is selected from at least one of lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate and lithium acetate, preferably lithium carbonate.
According to a preferred embodiment of the invention, the carbon source is selected from at least one of sucrose, glucose, fructose, lactose, citric acid and starch, preferably glucose. By adopting the embodiment, the carbon-coated lithium iron manganese phosphate anode material can be formed, so that the anode material is prevented from being in direct contact with electrolyte, mn dissolution is reduced, and the cycle performance of the material is improved.
According to a preferred embodiment of the invention, the metal element in the doped metal source is selected from at least one of Co, mg, ti, zr, al, V, cr, nb, preferably Mg and/or Ti. The kind of the metal-containing doped metal source is not particularly limited, and according to a preferred embodiment of the present invention, the metal-containing doped metal source includes sulfate, chloride, and nitrate containing the foregoing elements, and may be, for example, titanium sulfate, titanium chloride, titanium nitrate, aluminum sulfate, aluminum chloride, aluminum nitrate, and magnesium carbonate. With the foregoing embodiment, doping with a metal element causes defects inside the crystal to facilitate Li + And because of the charge difference generated by different charge valence states, cation vacancies are formed by a charge compensation mechanism, thereby improving the conductivity of the material and the rate capability of the material.
The second aspect of the invention provides a lithium iron manganese phosphate positive electrode material prepared by the preparation method of the lithium iron manganese phosphate positive electrode material in the first aspect.
In the invention, the lithium iron manganese phosphate anode material prepared by the preparation method has good carbon coating effect and high charge/discharge capacity, and can provide high-quality anode material for preparing high-capacity and high-conductivity lithium ion batteries.
The third aspect of the invention provides an application of the lithium iron manganese phosphate anode material in the technical field of lithium ion batteries.
In the invention, the lithium iron manganese phosphate anode material provided by the invention is manufactured into an anode plate, and can be combined with a cathode, a diaphragm and electrolyte to prepare a lithium ion battery.
According to a fourth aspect of the invention, there is provided a lithium ion battery comprising a positive electrode made of the positive electrode material of lithium iron manganese phosphate according to the second aspect, a negative electrode, a separator and an electrolyte.
The lithium iron manganese phosphate positive electrode material with high energy density, good conductivity and high charge/discharge capacity can be used for preparing a lithium ion battery with high capacity and long cycle with a negative electrode, a diaphragm and electrolyte.
The present invention will be described in detail by examples.
Example 1
(1) Adding 25kg of manganese carbonate into 50kg of pure water to fully dissolve and prepare a manganese carbonate solution with the mass fraction of 30%, adding 30kg of phosphoric acid with the concentration of 75% into 45kg of pure water to prepare a phosphoric acid solution with the mass fraction of 30%, adding the phosphoric acid solution into the manganese carbonate solution by a peristaltic pump at the stirring speed of 1000r/min for reaction, and then carrying out filter pressing, washing, drying and crystal water removal on the product to obtain a manganese phosphate precursor;
(2) Mixing manganese phosphate precursor, ferric phosphate, lithium carbonate, glucose and titanium nitrate uniformly according to the molar ratio of manganese to iron of 7:3, the molar ratio of lithium to phosphorus of 1.04:1, the weight percent of glucose of 11 and the weight percent of titanium nitrate, and then sanding at 25 ℃ for 13 hours, wherein D50 reaches 360nm, and D90 reaches 710nm; carrying out spray drying on the sand abrasive at the feeding speed of a feeding pump of 50L/h and the temperature of an air inlet of spraying of 190 ℃ and the temperature of an air outlet of spraying of 100 ℃ to obtain a spray material; and presintering the spray material for 3 hours at 400 ℃ in a nitrogen atmosphere, then heating to 750 ℃ for calcination for 7 hours, and naturally cooling to room temperature to obtain the lithium iron manganese phosphate anode material.
Example 2
(1) Adding 40kg of manganese acetate into 60kg of pure water to fully dissolve and prepare a manganese acetate solution with the mass fraction of 40%, adding 30kg of phosphoric acid with the concentration of 75% into 45kg of pure water to prepare a phosphoric acid solution with the mass fraction of 30%, adding the phosphoric acid solution into the manganese acetate solution by a peristaltic pump at the stirring speed of 900r/min for reaction, and then carrying out filter pressing, washing, drying and crystal water removal on the product to obtain a manganous phosphate precursor;
(2) Proportioning according to the molar ratio of manganese to iron of 7:3, the molar ratio of lithium to phosphorus of 1.04:1, the weight percent of glucose of 11 percent and the weight percent of titanium nitrate of 0.1 percent, uniformly mixing a manganous phosphate precursor with ferric phosphate, lithium carbonate, glucose and titanium nitrate, and then sanding for 14 hours at 25 ℃ until the D50 of the sand abrasive is 420nm and D90=780 nm; then carrying out spray drying on the sand abrasive under the condition that the feeding speed of a feeding pump is 50L/h, the temperature of an air inlet of spraying is 190 ℃, and the temperature of an air outlet of spraying is 100 ℃ to obtain a spray material; and presintering the spray material for 3 hours at 400 ℃ in a nitrogen atmosphere, then heating to 750 ℃ for calcination for 7 hours, and naturally cooling to room temperature to obtain the lithium iron manganese phosphate anode material.
Example 3
A lithium iron manganese phosphate cathode material was prepared according to the method of example 1, except that the addition order of the manganese carbonate solution and the phosphoric acid solution in step (1) was adjusted, i.e., the manganese carbonate solution was added to the phosphoric acid solution, and the results are shown in table 1.
Example 4
A lithium iron manganese phosphate cathode material was prepared in the same manner as in example 1, except that in step (1), a 50% by mass manganese citrate solution was prepared by substituting manganese citrate for manganese carbonate, and the results are shown in table 1.
Example 5
A lithium iron manganese phosphate cathode material was prepared in the same manner as in example 1, except that in step (2), titanium nitrate was replaced with magnesium carbonate of equal mass, and the results are shown in table 1.
Example 6
A lithium iron manganese phosphate positive electrode material was prepared according to the method of example 1, except that in step (2), the spray material was pre-burned at 400 ℃ for 3 hours under a nitrogen atmosphere, then heated to 650 ℃ for 10 hours, and naturally cooled to room temperature, thereby obtaining the lithium iron manganese phosphate positive electrode material. The results are shown in Table 1.
In the above examples, the capacity, rate charge and discharge performance of the lithium iron manganese phosphate cathode material were tested by CR2016 button cell.
The preparation method of the CR2016 button cell comprises the following steps:
(1) Preparation of the Positive electrode
2.5g of lithium iron manganese phosphate positive electrode material, 0.3125 binder PVDF HSV900 (Adama France) and 0.3125g of conductive agent Super-P were mixed by: firstly, taking NMP as a solvent, dissolving an adhesive to prepare a solution with the concentration of 6wt%, respectively mixing a lithium manganese iron phosphate positive electrode material, a conductive agent and the solution of the adhesive under stirring, stirring to form uniform slurry, uniformly coating the slurry on aluminum foil with the thickness of 20 mu m, drying at 100 ℃, and cutting into wafers with the diameter of 14.0mm, wherein the mass of active substances in the positive electrode sheet is about 0.0071g;
(2) Assembly of a battery
The positive plate is taken as a positive electrode, the lithium plate is taken as a negative electrode, the polypropylene film is taken as a diaphragm, and the battery cell assembly is assembled, and then the LiPF is assembled 6 And (3) dissolving the electrolyte in a mixed solvent of EC/DMC=1:1 (volume ratio) according to the concentration of 1mol/L to form a nonaqueous electrolyte, wherein the electrolyte is added in an amount which is based on the complete infiltration of a diaphragm and positive and negative electrodes, and then sealing the battery to prepare the CR2016 button battery.
The capacity test method of the lithium iron manganese phosphate anode material comprises the following steps:
(1) When a CR2016 button cell is manufactured, the mass m of an active material of a positive plate is recorded;
(2) Charging the button cell to 4.5V at a constant current of 0.1C (or 0.5C), maintaining constant voltage charging of 4.5V until the current is less than 0.01C, and discharging to 2.5V at a constant current of 0.1C (or 0.5C);
(3) Setting a 10-minute rest period between each two steps; the test results are shown in Table 1.
TABLE 1
Figure BDA0004152486250000101
Figure BDA0004152486250000111
Comparative examples 1, 2, 4 show that when manganese carbonate, manganese acetate and manganese citrate are used as the manganese source of the precursor, manganese citrate and manganese carbonate are superior to manganese acetate, and that the manganese carbonate and phosphoric acid reaction by-products are carbon dioxide, water and phosphoric acid, so that the manganese carbonate is used as the manganese source to be more easily handled;
as can be seen from comparative examples 1 and 3, the reaction performed by adding the phosphoric acid solution to the manganese carbonate solution is superior to the reaction performed by adding the manganese carbonate solution to the phosphoric acid solution;
comparative examples 1 and 5 show that similar results are obtained with titanium nitrate doping and magnesium carbonate doping;
comparative examples 1 and 6 show that the 650 ℃ sintering effect is significantly improved over 750 ℃ sintering effect, because smaller particles can be obtained at low temperature;
in summary, compared with examples 1-5, in example 6, manganese carbonate is used as a manganese source, a phosphoric acid solution is added into the manganese carbonate solution, metal element doping is performed through titanium nitrate, sintering is performed at a lower temperature (pre-sintering for 3 hours at 400 ℃ and then sintering for 10 hours at 650 ℃ in advance) in a nitrogen atmosphere, and the prepared lithium iron manganese phosphate anode material has higher capacity and better multiplying power charge-discharge performance.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (10)

1. The preparation method of the lithium iron manganese phosphate anode material is characterized by comprising the following steps of:
(1) Reacting the slurry or solution containing the manganese source with phosphoric acid solution, and performing post-treatment to obtain a manganous phosphate precursor;
(2) And mixing the manganous phosphate precursor with ferric phosphate, a lithium source, a carbon source and a doped metal source, and sequentially performing sanding, spray drying and sintering to obtain the lithium manganese phosphate anode material.
2. The process according to claim 1, wherein, in the step (1),
adding the manganese source-containing slurry or solution into a phosphoric acid solution for reaction or adding the phosphoric acid solution into the manganese source-containing slurry or solution for reaction;
preferably, the phosphoric acid solution is added to a slurry or solution containing a manganese source to effect a reaction under conditions including:
the stirring speed is 100-1000r/min, preferably 800-1000r/min; and/or
The addition time is 30-60min, preferably 30-40min;
and/or
The post-treatment comprises filter pressing, washing, drying and removing crystal water.
3. The production method according to claim 1 or 2, wherein, in the step (1),
the manganese source is calculated as bivalent manganese ion, phosphoric acid is calculated as phosphate radical, and the molar ratio of the manganese source to the phosphoric acid is 1 (1-1.1), preferably 1 (1.02-1.05); and/or
The mass concentration of the slurry or solution containing the manganese source is 30-60%, preferably 40-50%; and/or
The mass concentration of the phosphoric acid solution is 10-50%, preferably 20-40%.
4. A process according to any one of claim 1 to 3, wherein, in the step (2),
the manganous phosphate precursor is calculated by bivalent manganese ion, the ferric phosphate is calculated by ferric ion, the phosphorus source is calculated by the total phosphorus ion in the manganous phosphate and the ferric phosphate, the lithium source is calculated by lithium ion,
the molar ratio of the manganous phosphate precursor to the ferric phosphate is (1-5): 1, preferably (2-3): 1; and/or
The molar ratio of the lithium source to the phosphorus source is (1-1.1): 1, preferably (1.01-1.05): 1; and/or
Based on the total mass of the manganous phosphate precursor, the ferric phosphate and the lithium source as 100 percent,
the mass of the carbon source is 5-15%, preferably 8-13%; and/or
The mass of the doped metal source is 0.01-1%, preferably 0.1-0.5%.
5. The process according to any one of claims 1 to 4, wherein, in the step (2),
the manganous phosphate precursor is mixed with ferric phosphate, a lithium source, a carbon source and a doped metal source and then sanded until the D50 is 300-500nm and the D90 is 600-900nm, and preferably sanded until the D50 is 300-400nm and the D90 is 600-700nm;
preferably, the sanding conditions include:
the temperature is 10-60 ℃, preferably 20-30 ℃; and/or
The time is 5-20h, preferably 10-15h.
6. The production process according to any one of claims 1 to 5, wherein, in the step (2),
the spray drying conditions include:
the feeding speed of the feeding pump is 30-100L/h, preferably 50-70L/h; and/or
The temperature of the air inlet of the spray is 100-250 ℃, preferably 150-200 ℃; and/or
The temperature of the air outlet of the spray is 80-120 ℃, preferably 90-110 ℃;
and/or
The sintering conditions include:
the temperature is 400-800 ℃, preferably 500-750 ℃; and/or
The time is 10-20h, preferably 10-15h;
preferably, the sintering is heated to 400-600 ℃ under the protective atmosphere for calcination for 3-10 hours, and then heated to 650-800 ℃ for calcination for 7-10 hours;
preferably, the shielding gas is at least one of nitrogen, helium, neon, argon, krypton, xenon and radon, preferably nitrogen.
7. The process according to any one of claim 1 to 6, wherein,
the manganese source is selected from at least one of manganese oxide, manganese carbonate, manganese acetate, manganese hydroxide and manganese citrate, preferably at least one of manganese carbonate, manganese acetate and manganese citrate, more preferably manganese carbonate; and/or
The lithium source is at least one selected from lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate and lithium acetate, preferably lithium carbonate; and/or
The carbon source is at least one selected from sucrose, glucose, fructose, lactose, citric acid and starch, preferably glucose; and/or
The metal element in the doped metal source is selected from at least one of Co, mg, ti, zr, al, V, cr, nb, preferably Mg and/or Ti.
8. The lithium iron manganese phosphate positive electrode material prepared by the preparation method of any one of claims 1 to 7.
9. The application of the lithium iron manganese phosphate anode material in the technical field of lithium ion batteries.
10. A lithium ion battery, characterized in that the lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte, wherein the positive electrode, the negative electrode, the diaphragm and the electrolyte are made of the lithium manganese iron phosphate positive electrode material according to claim 8.
CN202310323104.5A 2023-03-29 2023-03-29 Lithium manganese iron phosphate positive electrode material, preparation method and application thereof, and lithium ion battery Pending CN116332147A (en)

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