CN109867268B - Preparation method of high-compaction high-capacity lithium iron phosphate - Google Patents
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Abstract
The invention discloses a preparation method of high-compaction high-capacity lithium iron phosphate. Weighing iron phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, and adding alcohol for wet grinding; spray drying the slurry, and crushing the spray-dried material to obtain crushed material; putting the crushed material into a roller furnace, sintering, wherein the sintering is divided into four stages, namely a heating stage, a heat preservation stage, a decarburization stage and a cooling stage, and discharging after cooling to a material temperature of less than 80 ℃ to obtain a calcined material; and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate. The method is simple and low in cost, and the lithium iron phosphate with high compaction density and good electrical property can be obtained by the gas treatment of carbon dioxide.
Description
Technical Field
The invention relates to a preparation method of high-compaction high-capacity lithium iron phosphate, belonging to the technical field of lithium battery anode materials.
Background
Lithium iron phosphate is a novel electrode material of lithium ion batteries. Its advantages are high discharge capacity, low cost, no poison and no environmental pollution. Countries around the world are competing to realize industrialized production. But its tap density is low, affecting the capacitance. The main production method is a high-temperature solid-phase synthesis method, and the product index is relatively stable.
The safety performance and the cycle life of the lithium iron phosphate are not comparable with those of other materials, and the safety performance and the cycle life are the most important technical indexes of the power battery. The 1C charging and discharging cycle life reaches 2000 times. The overcharged voltage of the single battery is 30V, and the single battery does not burn and does not explode when being punctured. The lithium iron phosphate anode material can be used in series connection of large-capacity lithium ion batteries more easily. So as to meet the requirement of frequent charging and discharging of the electric vehicle. The lithium ion battery anode material has the advantages of no toxicity, no pollution, good safety performance, wide raw material source, low price, long service life and the like, and is an ideal anode material of a new generation of lithium ion batteries.
However, with the adjustment of the national subsidy policy for new energy vehicles, the requirement on lithium iron phosphate materials is higher and higher, and particularly the requirement on the compaction density of lithium iron phosphate is higher and higher, at present, the highest requirement of lithium battery manufacturers on compaction reaches more than 2.5g/mL, and meanwhile, the requirement on the gram capacity of 0.1C is maintained to be more than 156 mAh.
However, the current methods for preparing high-compaction lithium iron phosphate mainly include raising sintering temperature, prolonging heat preservation time and reducing carbon content, but these methods have the following problems: the primary particle size of the lithium iron phosphate is large, so that the capacity of the lithium iron phosphate is low, and after the lithium iron phosphate is compacted to be higher than 2.45g/mL, the gram capacity requirement of 0.1C is smaller than 155 mAh.
Disclosure of Invention
In view of the above, the invention provides a preparation method of high-compaction high-capacity lithium iron phosphate, which is simple and low in cost, and can obtain lithium iron phosphate with high compaction density and good electrical property by carbon dioxide gas treatment, wherein the first discharge capacity at 0.1C is greater than 156mAh/g, the capacity attenuation rate after 1C cycle for 500 times is less than 10%, and the high-temperature cycle is good.
The invention solves the technical problems by the following technical means:
a preparation method of high-compaction high-capacity lithium iron phosphate comprises the following steps:
(1) weighing iron phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, adding alcohol for wet grinding, and obtaining slurry with the particle size of 400-500 nm;
(2) spray drying the slurry obtained in the step (1), condensing dried alcohol steam to obtain alcohol, crushing the spray-dried material to obtain crushed material with the particle size of 3-5 microns;
(3) putting the crushed material obtained in the step (2) into a roller furnace, sintering, wherein the sintering is divided into four stages, namely a temperature rising stage, a heat preservation stage, a decarbonization stage and a temperature reduction stage, nitrogen is introduced into the temperature rising stage and the heat preservation stage, carbon dioxide is introduced into the decarbonization stage and the temperature reduction stage, the temperature rising time of the temperature rising stage is 6-7h, the temperature rises to 760 and 790 ℃ and the temperature preservation time of the heat preservation stage is 7-9h, the temperature preservation temperature is 760 and 790 ℃, the temperature of the decarbonization stage is 700 and 720 ℃, the decarbonization time is 4-6h and the temperature reduction time of the temperature reduction stage is 4-5h, and discharging is carried out after the temperature of the material is reduced to less than 80 ℃ to obtain a calcined material;
(4) and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate.
The molar ratio of ferric phosphate to lithium carbonate to polyethylene glycol to sucrose in the step (1) is 1: 1.01-1.02: 0.05-0.1: 0.1-0.15 percent, the solid content of the obtained slurry is 40-50 percent, the wet grinding is carried out by adopting a sand mill, and zirconia balls are placed in the sand mill.
And (3) performing spray drying in the step (2) by adopting high-temperature nitrogen, wherein the temperature of the high-temperature nitrogen is 150-200 ℃, the temperature of an inner cavity of the spray dryer is maintained to be 80-100 ℃, alcohol vapor generated by spraying is condensed to recover alcohol, the residual gas is filtered by a precision filter and then returns to the spray dryer to be heated, and the alcohol content of the spray-dried material is lower than 0.5%.
And (3) crushing in the step (2) by using a jet mill.
And (3) in the calcining process, the temperature rising section and the temperature reduction section are both provided with air inducing ports, the air inducing ports are connected with an induced draft fan, the pressure of introduced nitrogen and carbon dioxide is the same and is 0.2-0.3MPa, and the temperature reduction section is cooled by cooling water.
In the step (4), the temperature in the constant-temperature and constant-humidity room is 20-25 ℃, the relative humidity is less than or equal to 15%, the materials are crushed until the particle size of the materials is 0.8-1 micron, the materials are sieved by a 80-mesh sieve during screening, and 2-level electromagnetic iron removal is adopted for iron removal.
The preparation method of the ferric phosphate in the step (1) comprises the steps of uniformly mixing ferrous salt and urea, heating to 95-100 ℃, stirring at the speed of 200-300r/min, reacting for 2-4h, adding hydrogen peroxide and phosphoric acid under stirring, reacting for 30-60min at the temperature of 80-90 ℃, adding the hydrogen peroxide and the phosphoric acid for 60-90min, filtering and washing to obtain ferric phosphate dihydrate, and calcining at the temperature of 650-700 ℃ to obtain the ferric phosphate.
The molar ratio of the ferrous salt to the urea to the hydrogen peroxide to the phosphoric acid is 1:1.5-2:0.55-0.6: 1.02-1.05.
The obtained ferric phosphate has D50 of 0.6-1.5 μm and BET of 1.5-2.5m2(ii)/g, tap density of 1.2-1.5g/mL, primary particle diameter of 200-400 nm.
The carbon content of the discharged material of the heat preservation section in the step (3) is maintained at 2-2.2%, and the carbon content of the calcined material is maintained at 0.8-1.1%.
According to the process, iron phosphate and lithium carbonate are used as an iron source and a lithium source, polyethylene glycol and sucrose are used as carbon sources, an organic system, namely an alcohol system, is adopted, so that the effects of dispersing and reducing energy consumption can be achieved, meanwhile, the recycling of an alcohol solvent can be realized by recycling alcohol, and the cost is further reduced;
meanwhile, the invention can obtain lithium iron phosphate with carbon content of 2-2.2% in a heat preservation section through the adjustment of a formula, the lithium iron phosphate has good electrical property and low compaction density, then a decarbonization section is added, carbon dioxide reacts with incandescent carbon at high temperature (700-.
In the decarbonization section, only carbon with high activity, intangibility and poor conductivity is consumed, and carbon with high conductivity is left, so that the capacity of the lithium iron phosphate is not reduced, and the compaction density of the product is improved.
In the heat preservation section, the growth of the primary particle size of the lithium iron phosphate is prevented due to the higher carbon content, and in the decarbonization section, only the decarbonization reaction is carried out, so that the growth of the primary particle size of the product is avoided, the capacity is also ensured, and the primary particle size of the finally obtained lithium iron phosphate is basically not more than 400 nm.
The carbon content of the finally obtained lithium iron phosphate is 0.8-1.1%, the 0.1C first discharge capacity is larger than 156mAh/g, the capacity fading rate of 500 times of 1C circulation is smaller than 10%, and the high-temperature circulation is good.
Meanwhile, the invention provides a novel preparation method of the iron phosphate, which comprises the steps of firstly preparing ferrous hydroxide with uniform particles by a homogeneous precipitation method, then adding phosphoric acid and hydrogen peroxide to realize oxidation and precipitation conversion to obtain the iron phosphate.
The invention has the beneficial effects that: the method is simple and low in cost, and meanwhile, the lithium iron phosphate with high compaction density and good electrical property can be obtained through the gas treatment of carbon dioxide, the 0.1C first discharge capacity is larger than 156mAh/g, the capacity attenuation rate of 500 times of 1C circulation is smaller than 10%, and the high-temperature circulation is good.
Drawings
FIG. 1 is a SEM of example 1 of the present invention.
FIG. 2 is a SEM of example 2 of the invention.
FIG. 3 is a SEM of example 3 of the invention.
Figure 4 is an XRD of example 1 of the invention.
Figure 5 is an XRD of example 2 of the invention.
Figure 6 is an XRD of example 3 of the invention.
Detailed Description
The invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Example 1
A preparation method of high-compaction high-capacity lithium iron phosphate comprises the following steps:
(1) weighing ferric phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, adding alcohol, and carrying out wet grinding to obtain slurry with the particle size of 455 nm;
(2) spray drying the slurry obtained in the step (1), condensing dried alcohol steam to obtain alcohol, crushing the spray-dried material to obtain crushed material with the particle size of 4 microns;
(3) putting the crushed material obtained in the step (2) into a roller furnace, sintering, wherein the sintering is divided into four stages, namely a heating stage, a heat preservation stage, a decarbonization stage and a cooling stage, nitrogen is introduced into the heating stage and the heat preservation stage, carbon dioxide is introduced into the decarbonization stage and the cooling stage, the heating time of the heating stage is 6.5 hours, the temperature is increased to 780 ℃, the heat preservation time of the heat preservation stage is 9 hours, the heat preservation temperature is 780 ℃, the temperature of the decarbonization stage is 710 ℃, the decarbonization time is 6 hours, the cooling time of the cooling stage is 5 hours, and discharging is carried out after the temperature is reduced to less than 80 ℃ to obtain a calcined material;
(4) and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate.
The molar ratio of ferric phosphate to lithium carbonate to polyethylene glycol to sucrose in the step (1) is 1: 1.015: 0.08: 0.12, the solid content in the obtained slurry is 48 percent, wet grinding is carried out by adopting a sand mill, and zirconia balls are placed in the sand mill.
And (3) performing spray drying in the step (2) by adopting high-temperature nitrogen, wherein the temperature of the high-temperature nitrogen is 180 ℃, the temperature of an inner cavity of a spray dryer is maintained to be 85 ℃, alcohol vapor generated by spraying is condensed to recover alcohol, the residual gas is filtered by a precision filter and then returns to the spray dryer to be heated, and the alcohol content of the spray-dried material is lower than 0.5%.
And (3) crushing in the step (2) by using a jet mill.
And (3) in the calcining process, the temperature rising section and the temperature reduction section are both provided with air inducing ports, the air inducing ports are connected with an induced draft fan, the pressure of introduced nitrogen and carbon dioxide is the same and is 0.25MPa, and the temperature reduction section is cooled by cooling water.
And (4) crushing the materials until the particle size of the materials is 0.88 microns under the condition that the temperature in the constant-temperature and constant-humidity room is 25 ℃ and the relative humidity is less than or equal to 15 percent in the step (4), and sieving the materials by using a 80-mesh sieve during sieving to remove iron by adopting 2-level electromagnetic iron removal.
The preparation method of the ferric phosphate in the step (1) comprises the steps of uniformly mixing ferrous salt and urea, heating to 98 ℃, stirring at a speed of 250r/min, reacting for 4 hours, adding hydrogen peroxide and phosphoric acid under stirring, reacting for 55 minutes at 85 ℃, adding the hydrogen peroxide and the phosphoric acid for 80 minutes, filtering and washing to obtain ferric phosphate dihydrate, and calcining at 685 ℃ to obtain the ferric phosphate.
The molar ratio of the ferrous salt to the urea to the hydrogen peroxide to the phosphoric acid is 1:1.8:0.58: 1.04.
The iron phosphate obtained had a D50 of 0.95. mu.m and a BET of 1.9m2(ii)/g, tap density of 1.28g/mL, primary particle diameter of 310 nm.
The carbon content of the discharged material of the heat preservation section in the step (3) is maintained at 2.13 percent, and the carbon content of the calcined material is maintained at 0.92 percent.
As shown in fig. 1 and 4, the final product is nearly spherical or spheroidal, the surface is smooth, the crystal form is complete, and the final product has the following indexes:
example 2
A preparation method of high-compaction high-capacity lithium iron phosphate comprises the following steps:
(1) weighing iron phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, adding alcohol, and performing wet grinding to obtain slurry with the particle size of 420 nm;
(2) spray drying the slurry obtained in the step (1), condensing dried alcohol steam to obtain alcohol, crushing the spray-dried material to 5 microns in particle size to obtain crushed material;
(3) putting the crushed material obtained in the step (2) into a roller furnace, sintering, wherein the sintering is divided into four stages, namely a heating stage, a heat preservation stage, a decarbonization stage and a cooling stage, nitrogen is introduced into the heating stage and the heat preservation stage, carbon dioxide is introduced into the decarbonization stage and the cooling stage, the heating time of the heating stage is 7 hours, the temperature is increased to 785 ℃, the heat preservation time of the heat preservation stage is 8 hours, the heat preservation temperature is 785 ℃, the temperature of the decarbonization stage is 705 ℃, the decarbonization time is 6 hours, the cooling time of the cooling stage is 4 hours, and discharging is carried out after the temperature is reduced to less than 80 ℃ to obtain a calcined material;
(4) and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate.
The molar ratio of ferric phosphate to lithium carbonate to polyethylene glycol to sucrose in the step (1) is 1: 1.015: 0.08: 0.12, the solid content in the obtained slurry is 48 percent, wet grinding is carried out by adopting a sand mill, and zirconia balls are placed in the sand mill.
And (3) performing spray drying in the step (2) by adopting high-temperature nitrogen, wherein the temperature of the high-temperature nitrogen is 180 ℃, the temperature of an inner cavity of a spray dryer is maintained to be 85 ℃, alcohol vapor generated by spraying is condensed to recover alcohol, the residual gas is filtered by a precision filter and then returns to the spray dryer to be heated, and the alcohol content of the spray-dried material is lower than 0.5%.
And (3) crushing in the step (2) by using a jet mill.
And (3) in the calcining process, the temperature rising section and the temperature reduction section are both provided with air inducing ports, the air inducing ports are connected with an induced draft fan, the pressure of introduced nitrogen and carbon dioxide is the same and is 0.25MPa, and the temperature reduction section is cooled by cooling water.
And (4) crushing the materials until the particle size of the materials is 0.83 microns under the condition that the temperature in the constant-temperature and constant-humidity room is 25 ℃ and the relative humidity is less than or equal to 15 percent in the step (4), and sieving the materials by using a 80-mesh sieve during sieving, wherein 2-level electromagnetic iron removal is adopted for iron removal.
The preparation method of the ferric phosphate in the step (1) comprises the steps of uniformly mixing ferrous salt and urea, heating to 98 ℃, stirring at a speed of 250r/min, reacting for 4 hours, adding hydrogen peroxide and phosphoric acid under stirring, reacting for 55 minutes at 85 ℃, adding the hydrogen peroxide and the phosphoric acid for 80 minutes, filtering and washing to obtain ferric phosphate dihydrate, and calcining at 685 ℃ to obtain the ferric phosphate.
The molar ratio of the ferrous salt to the urea to the hydrogen peroxide to the phosphoric acid is 1:1.8:0.58: 1.04.
The iron phosphate obtained had a D50 of 0.94. mu.m and a BET of 1.92m2(ii)/g, tap density of 1.27g/mL, primary particle diameter of 319 nm.
The carbon content of the discharged material of the heat preservation section in the step (3) is maintained at 2.15 percent, and the carbon content of the calcined material is maintained at 0.93 percent.
As shown in fig. 2 and 5, the final product is nearly spherical or spheroidal, the surface is smooth, the crystal form is complete, and the final product has the following indexes:
example 3
A preparation method of high-compaction high-capacity lithium iron phosphate comprises the following steps:
(1) weighing iron phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, adding alcohol, and performing wet grinding to obtain slurry with the particle size of 445 nm;
(2) spray drying the slurry obtained in the step (1), condensing dried alcohol steam to obtain alcohol, crushing the spray-dried material to obtain crushed material with the particle size of 4.2 microns;
(3) putting the crushed material obtained in the step (2) into a roller furnace, sintering, wherein the sintering is divided into four stages, namely a heating stage, a heat preservation stage, a decarbonization stage and a cooling stage, nitrogen is introduced into the heating stage and the heat preservation stage, carbon dioxide is introduced into the decarbonization stage and the cooling stage, the heating time of the heating stage is 7 hours, the temperature is increased to 775 ℃, the heat preservation time of the heat preservation stage is 9 hours, the heat preservation temperature is 775 ℃, the temperature of the decarbonization stage is 710 ℃, the decarbonization time is 6 hours, the cooling time of the cooling stage is 4 hours, and discharging is carried out after the temperature is reduced to the material temperature less than 80 ℃ to obtain a calcined material;
(4) and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate.
The molar ratio of ferric phosphate to lithium carbonate to polyethylene glycol to sucrose in the step (1) is 1: 1.018: 0.08: 0.13, the solid content in the obtained slurry is 45%, wet grinding is carried out by adopting a sand mill, and zirconia balls are placed in the sand mill.
And (3) performing spray drying in the step (2) by adopting high-temperature nitrogen, wherein the temperature of the high-temperature nitrogen is 185 ℃, the temperature of an inner cavity of the spray dryer is maintained to be 90 ℃, alcohol vapor generated by spraying is condensed to recover alcohol, the residual gas is filtered by a precision filter and then returns to the spray dryer to be heated, and the alcohol content of the spray-dried material is lower than 0.5%.
And (3) crushing in the step (2) by using a jet mill.
And (3) in the calcining process, the temperature rising section and the temperature reduction section are both provided with air inducing ports, the air inducing ports are connected with an induced draft fan, the pressure of introduced nitrogen and carbon dioxide is the same and is 0.28MPa, and the temperature reduction section is cooled by cooling water.
And (4) crushing the materials until the particle size of the materials is 0.95 micron at the temperature of 24 ℃ and the relative humidity of less than or equal to 15% in the constant-temperature and constant-humidity room in the step (4), and sieving the materials by a 80-mesh sieve to remove iron by 2-level electromagnetic iron removal.
The preparation method of the ferric phosphate in the step (1) comprises the steps of uniformly mixing ferrous salt and urea, heating to 98 ℃, stirring at 215r/min for reaction for 3 hours, adding hydrogen peroxide and phosphoric acid under stirring, reacting at 85 ℃ for 55 minutes, adding the hydrogen peroxide and the phosphoric acid for 85 minutes, filtering and washing to obtain ferric phosphate dihydrate, and calcining at 685 ℃ to obtain the ferric phosphate.
The molar ratio of the ferrous salt to the urea to the hydrogen peroxide to the phosphoric acid is 1:1.8:0.58: 1.04.
The iron phosphate obtained had a D50 of 1.3 μm and a BET of 2.4m2(ii)/g, tap density of 1.37g/mL, primary particle diameter of 325 nm.
The carbon content of the discharged material of the heat preservation section in the step (3) is maintained at 2.15 percent, and the carbon content of the calcined material is maintained at 1.03 percent.
As shown in fig. 3 and 6, the final product is nearly spherical or spheroidal, the surface is smooth, the crystal form is complete, and the final product has the following indexes:
finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (5)
1. A preparation method of high-compaction high-capacity lithium iron phosphate is characterized by comprising the following steps:
(1) weighing ferric phosphate, lithium carbonate, polyethylene glycol and sucrose, mixing, adding alcohol for wet grinding to obtain slurry with the particle size of 400-500nm, wherein the preparation method of the ferric phosphate comprises the steps of uniformly mixing ferrous salt and urea, heating to 95-100 ℃, stirring at the speed of 200-300r/min, reacting for 2-4h, adding hydrogen peroxide and phosphoric acid under the stirring condition, and stirring at the temperature of 80-Reacting at 90 ℃ for 30-60min, adding hydrogen peroxide and phosphoric acid for 60-90min, filtering and washing to obtain ferric phosphate dihydrate, calcining at 650-plus 700 ℃ to obtain ferric phosphate, wherein the molar ratio of ferrous salt, urea, hydrogen peroxide and phosphoric acid is 1:1.5-2:0.55-0.6:1.02-1.05, the D50 of the obtained ferric phosphate is 0.6-1.5 mu m, and the BET is 1.5-2.5m2(ii)/g, tap density of 1.2-1.5g/mL, primary particle size of 200-400 nm;
(2) spray drying the slurry obtained in the step (1), condensing dried alcohol steam to obtain alcohol, crushing the spray-dried material to obtain crushed material with the particle size of 3-5 microns, performing spray drying by adopting high-temperature nitrogen at the temperature of 150 ℃ and 200 ℃, maintaining the temperature of an inner cavity of a spray dryer at 80-100 ℃, condensing the alcohol steam generated by spraying to recover alcohol, filtering the residual gas by a precision filter, and returning the filtered gas to the spray dryer for heating, wherein the alcohol content of the spray-dried material is lower than 0.5%;
(3) putting the crushed material obtained in the step (2) into a roller furnace for sintering, wherein the sintering is divided into four stages, namely a temperature rising stage, a heat preservation stage, a decarbonization stage and a temperature reduction stage, nitrogen is introduced into the temperature rising stage and the heat preservation stage, carbon dioxide is introduced into the decarbonization stage and the temperature reduction stage, the temperature rising stage has the temperature rising time of 6-7h, the temperature rises to 760 and 790 ℃ and the temperature preservation stage has the temperature preservation time of 7-9h, the temperature preservation stage has the temperature of 760 and 790 ℃, the decarbonization stage has the temperature of 700 and 720 ℃, the decarbonization time is 4-6h and the temperature reduction stage has the temperature reduction time of 4-5h, discharging is carried out after the temperature is reduced to the material temperature of less than 80 ℃, thus obtaining the calcined material, the calcining process is carried out, the temperature rising stage and the temperature reduction stage are both provided with air inlets, the air inlets are connected with an induced draft fan, the pressures of the introduced nitrogen and the carbon dioxide are the same and are, cooling the cooling section by adopting cooling water;
(4) and crushing, screening and deironing the calcined material in a constant temperature and humidity room, and then vacuumizing and packaging to obtain the high-compaction high-capacity lithium iron phosphate.
2. The method for preparing high-compaction high-capacity lithium iron phosphate according to claim 1, wherein the method comprises the following steps: the molar ratio of ferric phosphate to lithium carbonate to polyethylene glycol to sucrose in the step (1) is 1: 1.01-1.02: 0.05-0.1: 0.1-0.15 percent, the solid content of the obtained slurry is 40-50 percent, the wet grinding is carried out by adopting a sand mill, and zirconia balls are placed in the sand mill.
3. The method for preparing high-compaction high-capacity lithium iron phosphate according to claim 1, wherein the method comprises the following steps: and (3) crushing in the step (2) by using a jet mill.
4. The method for preparing high-compaction high-capacity lithium iron phosphate according to claim 1, wherein the method comprises the following steps: in the step (4), the temperature in the constant-temperature and constant-humidity room is 20-25 ℃, the relative humidity is less than or equal to 15%, the materials are crushed until the particle size of the materials is 0.8-1 micron, the materials are sieved by a 80-mesh sieve during screening, and 2-level electromagnetic iron removal is adopted for iron removal.
5. The method for preparing high-compaction high-capacity lithium iron phosphate according to claim 1, wherein the method comprises the following steps: the carbon content of the discharged material of the heat preservation section in the step (3) is maintained at 2-2.2%, and the carbon content of the calcined material is maintained at 0.8-1.1%.
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| CN111533103A (en) * | 2020-05-08 | 2020-08-14 | 蒋达金 | High-compaction ferric phosphate and preparation method of high-compaction lithium ferric phosphate |
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| CN109867268A (en) | 2019-06-11 |
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