CN102381693A - Preparation method of lithium iron phosphate - Google Patents
Preparation method of lithium iron phosphate Download PDFInfo
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- CN102381693A CN102381693A CN2010102730091A CN201010273009A CN102381693A CN 102381693 A CN102381693 A CN 102381693A CN 2010102730091 A CN2010102730091 A CN 2010102730091A CN 201010273009 A CN201010273009 A CN 201010273009A CN 102381693 A CN102381693 A CN 102381693A
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Abstract
The invention provides a preparation method of lithium iron phosphate, wherein the method comprises the following steps of: (1) mixing the fluid flow of an aqueous solution containing an iron source and a phosphorus source with the fluid flow of an aqueous solution containing a lithium source in a concurrent flow charging way at an inert atmosphere, raising the temperature to 150-250 DEG C after the charging is finished, reacting for 4-8h under stirring, cooling to the temperature lower than 80 DEG C, and filtering to obtain a lithium iron phosphate precursor; (2) mixing the lithium iron phosphate precursor obtained in the step (1), a soluble carbon source additive and water to obtain size with the solid content of 30-40wt%, spray-drying the size under the condition that the mass loss of a dried product is not larger than 5wt% below 800 DEG C; and (3) roasting the product obtained in the step (2). The lithium iron phosphate product obtained by using the method provided by the invention has favorable electrochemical performance.
Description
Technical field
The present invention relates to a kind of preparation method of LiFePO 4.
Background technology
Since last century, the nineties lithium ion battery was realized commercial applications; Its Application Areas develops to usefulness large vol such as power tool, electromobile, high power power direction from small-sized portable power sources such as mobile communication, laptop computers, and this security and chemical property to battery is had higher requirement.(the LiCoO of cobalt system with present widespread use
2), (Li of manganese system
2Mn
2O
4) positive electrode material compares, and has the LiFePO 4 (LiFePO of rhombic system olivine structural
4) be considered to the power type lithium-ion battery anode material of tool application prospect.
The compound method of ferrousphosphate lithium material can be divided into solid reaction process and wet chemistry method from reaction formation.Solid reaction process is about to solid material to be mixed by certain proportioning, and warp grinds, calcines repeatedly and powder essence finally makes product.Like US 591382, US 6085015, US 6702961 and CN1581537A etc., used lithium source is mainly Quilonum Retard or Lithium Hydroxide MonoHydrate, and used phosphorus source is that primary ammonium phosphate or monometallic, used source of iron are red oxide of iron, iron powder or Ferrox.The performance of product depends on the kind and the physical and chemical performance of source of iron to a great extent, in the preparation process or have a large amount of ammonias, dioxide gas to emit, and needs to grind repeatedly, is difficult to guarantee the chemical property of product and stability in batches in the production.
Compare with solid reaction process, wet chemistry method prepares that reaction raw materials can mix at molecular level in the process.Adopt liquid-phase coprecipitation like WO02083555A2,, make its formation contain the phosphoric acid salt and the ferrous phosphate mixture of lithium, the i.e. presoma of LiFePO 4 through the pH value of conditioned reaction system.This presoma is made the LiFePO 4 that particle diameter is the 2-3 micron under 650-800 ℃, calcining again after 150 ℃ of dryings.In this method, whole process places nitrogen protection, and this processing condition are unfavorable for industrialization production, does not show the quality of its high rate performance in the patent.
CN101117216A discloses a kind of method of hydrothermal method synthesizing lithium ferrous phosphate, with ferrous sulfate, phosphoric acid, the Lithium Hydroxide MonoHydrate LiFePO 4 that has been feedstock production, does not show the quality of gained material high temperature performance in the patent.
CN1635648A discloses a kind of method that adopts the wet chemistry method synthesizing lithium ferrous phosphate; This method comprises the presoma tertiary iron phosphate of preparation iron earlier; Prepare the spherical LiFePO 4 with high-bulk-density with lithium source, carbon source and doped metal ion compound through calcining again, the material granule granularity is bigger, is solid sphere; The evolving path of lithium ion is longer, is unfavorable for the performance of high rate performance.
Summary of the invention
Goal of the invention of the present invention is to overcome the deficiency that exists in the prior art, a kind of low cost, product batches good stability are provided, have higher specific storage, the preparation method of the LiFePO 4 of good multiplying power discharging property, stable circulation performance, low temperature discharge ability and pole piece coating performance.
The invention provides a kind of preparation method of LiFePO 4, wherein, this method comprises the steps:
The aqueous solution liquid flow that (1) will contain source of iron and phosphorus source is mixed with aqueous solution liquid flow mode with cocurrent adding material in inert atmosphere in lithium source; And use the pH value of the mixture that pH value regulator control obtains to be 7-9, the mol ratio of Li: Fe: P is 1.5-3 in said lithium source, source of iron and the phosphorus source: 1: 1.04-1.1, feed in raw material finish after; Be warming up to 150-250 ℃; Under agitation react 4-8 hour, and be cooled to below 80 ℃, filter; Washing precipitation to sulphate content or chloride content obtain lithium iron phosphate precursor less than 0.5 weight %;
(2) lithium iron phosphate precursor that step (1) is obtained mixes with soluble carbon source additive and water, obtains the slurry that solid content is 30-40 weight %, and wherein, the weight ratio of lithium iron phosphate precursor and soluble carbon source additive is 100: 10-20; Said slurry is carried out spraying drying, and spray-dired condition makes the desciccate that obtains be not more than 5 weight % at the weight loss of heating under 800 ℃;
(3) product that step (2) is obtained carries out roasting.
The present invention at first adopts wet chemistry method synthesizing lithium ferrous phosphate presoma; Mode through adopting cocurrent adding material comparatively forms in the constant pH scope at one with the assurance lithium iron phosphate precursor; The pH value of control proportion of raw materials and reaction system is controlled the composition of product; After the reacting by heating; The lithium iron phosphate precursor that obtains is mixed with the water dissolvable carbon source of liquid form, improved the carbon cladding uniformity, and carry out drying through spray-dired method and control degree of drying simultaneously; The moisture content of the part-structure property in free moisture content and the carbon source in the ferrous lithium presoma of dephosphorylate simultaneously, the chemical property that has improved product with and the coating that helps electrode slice process.
Description of drawings
Fig. 1 is the transmission electron microscope photo of the ferrous phosphate lithium/carbon mixture that obtains according to the method for the embodiment of the invention 1;
The discharge curve of ferrous phosphate lithium/carbon mixture under different multiplying that Fig. 2 obtains for the method according to the embodiment of the invention 1;
Fig. 3 is the low-temperature performance curve of the ferrous phosphate lithium/carbon mixture that obtains according to the method for the embodiment of the invention 1.
Embodiment
According to the present invention, the preparation method of said LiFePO 4 comprises the steps:
The aqueous solution liquid flow that (1) will contain source of iron and phosphorus source is mixed with aqueous solution liquid flow mode with cocurrent adding material in inert atmosphere in lithium source, and uses the pH value of the mixture that pH value regulator control obtains to be 7-9, and the mol ratio of Li: Fe: P is 1.5-3 in said lithium source, source of iron and the phosphorus source: 1: 1.04-1.1; Behind reinforced the finishing; Be warming up to 150-250 ℃, under agitation react 4-8 hour, and be cooled to below 80 ℃; Filter; Washing precipitation to sulphate content or chloride content preferably less than 0.2 weight %, obtain lithium iron phosphate precursor less than 0.5 weight %;
(2) lithium iron phosphate precursor that step (1) is obtained mixes with soluble carbon source additive and water, obtains the slurry that solid content is 30-40 weight %, and wherein, the weight ratio of lithium iron phosphate precursor and soluble carbon source additive is 100: 10-20; Said slurry is carried out spraying drying, and the weight loss when spray-dired condition makes the desciccate that obtains under inert atmosphere, be heated to 800 ℃ is not more than 5 weight %;
(3) product that step (2) is obtained carries out roasting.
Contriver of the present invention finds, if the adding mode of the liquid stock of step (1) is not and stream mode, contains more impurity in the ferrous phosphate crystalline lithium that obtains, and is unfavorable for the raising of product chemical property.In addition, contain the source of iron in the aqueous solution liquid flow in aqueous solution liquid flow and lithium source in source of iron and phosphorus source, the mol ratio in phosphorus source is preferably 1: 1.04-1.1.If the phosphorus source is very few, because of the resolvability of phosphorus, the theory that does not reach iron/phosphorus in the product is than more than 1, and causes producing the phosphorus deficiency; If the phosphorus source is too much, then the content of Trilithium phosphate increases in the product, because it belongs to inactive substance, and can influence the chemical property of the LiFePO 4 that finally obtains.Same solubility because of lithium ion, the mole proportioning in lithium source should be theoretical than more than 1 greater than it.
Said phosphorus source can be selected from the phosphorus compound of the various water dissolvables that are used to prepare LiFePO 4, like H
3PO
4, LiH
2PO
4And NH
4H
2PO
4In one or more mixtures.
Said source of iron can be selected from the ferrous compound of the various water dissolvables that are used to prepare LiFePO 4, like one or both mixtures of ferrous sulfate, iron protochloride.
Said lithium source can be selected from the lithium compound of the various water dissolvables that are used to prepare LiFePO 4, like LiOH and LiH
2PO
4In one or both mixtures.
According to the present invention; Contain less impurity in order to make in the ferrous phosphate crystalline lithium that obtains; Be beneficial to the raising of product chemical property; In said step (1), the aqueous solution liquid flow that will contain source of iron and phosphorus source is mixed with the mode of cocurrent adding material with the aqueous solution liquid flow in lithium source for the aqueous solution liquid flow that will contain source of iron and phosphorus source with aqueous solution liquid flow method of mixing in nitrogen atmosphere in lithium source, more preferably under agitation carries out.Under the preferable case; The reinforced volume that PM contains the aqueous solution liquid flow in source of iron and phosphorus source is the 1/10-1/30 of the TV of the aqueous solution to be added, and the reinforced volume of the aqueous solution liquid flow in PM lithium source is the 1/10-1/30 of the TV of the aqueous solution to be added; And preferably keep above-mentioned two bursts of liquid flow reinforced, and in the identical time, add with at the uniform velocity.
According to the present invention; The condition of the roasting in the drying conditions of step (2) and the step (3) can be the conventional condition in this area, for example, and in step (2); Said drying conditions is included in and carries out spraying drying under air atmosphere or the inert atmosphere; 300-400 ℃ of inlet gas temperature, temperature out is 100-150 ℃, makes the weight loss of desciccate under 800 ℃ that obtains be not more than 5 weight %.
In step (3), said roasting condition is included under the inert atmosphere, 650-780 ℃ with normal pressure under roasting 4-10 hour.
In order further to control the LiFePO 4 that obtains excellent property, in step (3), preferably the heat-up rate with 1-8 ℃/min is warming up to 300-400 ℃ earlier; Be incubated after 1-2 hour; Be warmed up to 650-780 ℃ with same heat-up rate again, and be incubated 4-10 hour, be cooled to then below 100 ℃.Wherein, said inert atmosphere refers to not any one gas or the gaseous mixture with reactant and product generation chemical reaction, like in nitrogen and the periodic table of elements zero group gas one or more.This inert atmosphere be preferably gas flow rate be the 2-50 liter/minute mobile atmosphere.
According to the present invention, for fear of the oxidation of source of iron, under the preferable case, this method also is included in the step (1), and with xitix powder and the step that contains the aqueous solution in source of iron and phosphorus source, the add-on of said xitix can be 0.1-0.5g/L.
According to the present invention, in step (2), the soluble carbon source additive is mixed with the product of step (1) in liquid phase, and adopt spray-dired method that the slurry that obtains is carried out drying.Control exsiccant degree; Make when the weight loss of dried desciccate under 800 ℃ is not more than 5 weight %; Be preferably 1.5-4.5 weight %; Can remove the free water of product particle surface and the structural moisture content in the carbon source additive molecule so simultaneously, so that in follow-up calcination process, can water-gas reaction not take place because of the existence of a large amount of steam.Because of the existence of water-gas can make the reductibility of atmosphere excessive, cause the phosphate anion reduction, generate impurity, reduce the electrochemistry capacitance and the cycle performance of material.
The present invention preferably is defined as less than 400 ℃ said exsiccant condition; Temperature is too high; May cause the ferrous oxidation in step (1) products therefrom; Be no more than 5 weight % as long as guarantee the weight loss of desciccate in being heated to 800 ℃ process and after keeping 1-5 hour under this temperature, just can guarantee to remove structural moisture content in free water and the part carbon source additive in the product; Under the preferable case, in said step (2), spray-dired condition comprises that the exsiccant inlet temperature is 300-400 ℃, and temperature out is 100-150 ℃.
Said soluble carbon source additive can be selected from and well known in the artly can play carbon source additive electric action, solubility, as being selected from Zulkovsky starch, Z 150PH, sucrose, glucose, the resol resin one or more.
According to the present invention, the pattern that adopts wet chemistry method synthetic lithium iron phosphate precursor is that diameter is that 0.5-1 μ m, thickness are the class disk shape particle (like Fig. 1) of 70-100nm.
To further describe in detail the present invention through specific embodiment below.
In following embodiment, under nitrogen protection, to measure the weight loss of treating calcining matter with the TGA/DSC1 thermal analyzer of Switzerland's plum Teller-holder benefit company and change, test condition is 5 ℃/min, ends at 800 ℃; The Mastersizer 2000E laser particle analyzer of employing Britain Ma Erwen company is measured the granularity of the ferrous phosphate lithium/carbon composite material that obtains; The specific surface area of the ferrous phosphate lithium/carbon composite material that the Autosorb-3B type nitrogen adsorption appearance that adopts U.S. Kang Ta instrument company obtains with determination of nitrogen adsorption.
The chemical property measuring method of material: according to ferrous phosphate lithium/carbon composite material: conductive carbon black: the weight ratio of pvdf is 9: 1: 1 a ratio batching.The N-Methyl pyrrolidone solution (6 weight %) of ferrous phosphate lithium/carbon mixture, conductive carbon black and pvdf is mixed into uniform slurry; Evenly coat on the aluminum foil current collector; In 120 ℃ of oven dry 2 hours, be rolled into the positive plate that thickness is about 100-120 μ m.Cut-off directly is the positive pole of the disk of 18mm as battery, is the negative pole of the lithium sheet of 20mm as battery with the diameter, is the barrier film of battery with Celgard 2400, with the LiFP of 1M
6Organic solution (EC: DEC: EMC=1: 1: 1) be ionogen, be assembled into 2430 type button cells, carry out the discharge test under the different multiplying, the charge and discharge stopping potential is respectively 4.2V and 2.3V.Wherein, the curve that is lower than 0.1C discharge adopts the identical multiplying power of charge and discharge when discharging and recharging, and the discharge curve that is higher than 1C then adopts the system that discharges and recharges of 1C charging, high-multiplying power discharge.The high rate performance curve of ferrous phosphate lithium/carbon composite material is seen Fig. 2, and the low-temperature performance curve is seen Fig. 3.
The specific discharge capacity of different sample ferrous phosphate lithium/carbon composite materials under different multiplying seen table 1.
Embodiment 1
Present embodiment is used to explain the preparation of LiFePO 4 provided by the invention.
(1) take by weighing ferrous sulfate (the ferrous 99.55 weight % of sulfur acid) 27.93kg (100mol), phosphoric acid (mass percent concentration is 85.25%) 12.07kg (105mol), at room temperature; Elder generation's water is diluted to 80L with phosphoric acid; Again it is added in the ferrous sulfate, be stirred to dissolving, in this solution, add 25g xitix powder; Add water to 100L, obtain containing the acidic aqueous solution A in source of iron and phosphorus source; Take by weighing 12.60kg Lithium Hydroxide Monohydrate (99.98%), water-soluble, and be diluted to 100L, obtain containing the alkaline aqueous solution B in lithium source.Prepare the pH value regulator of the Lithium Hydroxide MonoHydrate of 20g/L as reaction system in addition, this is a solution C.
(2) earlier with the nitrogen purging retort to remove air wherein; Start stirring; Add said acidic aqueous solution A, said alkaline aqueous solution B simultaneously, feed rate be 8L/min (the reinforced volume of the said liquid flow of PM be the aqueous solution to be added TV 1/12.5), behind reinforced the end; Stirred 30 minutes, using the pH value of small volume of solution C conditioned reaction system is 8.5.Then, be warming up to 150 ℃, and continued stirring reaction 8 hours, the interior pressure of retort this moment comes from the autogenous pressure of water vapor, i.e. the saturated vapor pressure 0.38Mpa of water vapor under this temperature.After reaction finishes, be cooled to below 80 ℃, filter, wash to sulphate content less than 0.2 weight % (with respect to dry material), filter cake 33.4kg, be 48.5% through measuring its solid content, promptly contain amount of solid 16.2kg.
(3) in above-mentioned filtration gained filter cake thing, add 1.62kg glucose, add the 20L deionized water again, be mixed with the slurry that solid content is about 30 weight %.Dry with centrifugal spray dryer, 400 ℃ of inlet temperatures, 140 ℃ of temperature outs obtain Powdered desciccate.Under nitrogen atmosphere, be warming up to 800 ℃ through measuring the desciccate that obtains after the spraying drying, and the weight loss of keeping after 1 hour is about 4.2 weight %.It is the intermittent type calcining furnace of 800L that above-mentioned powder is placed volume, under nitrogen protection, is warmed up to 350 ℃ with the heat-up rate of 8 ℃/min; Be incubated after 1 hour, be warmed up to 750 ℃ with same heat-up rate again, and after being incubated 8 hours; Naturally cool to below 100 ℃, take out.
Wherein, the transmission electron microscope photo of the lithium iron phosphate precursor that obtains of step (2) is as shown in Figure 1.Show its type of being disk shape crystallization among the figure, thickness is 70-100nm.Early stage, a large amount of research reports showed that this direction is the lithium ion dispersal direction.This shows that the inventive method can significantly shorten the evolving path of lithium ion.
The testing graininess result is D
50=5.3 μ m; The BET specific surface area is 13.6m
2/ g; Tap density is 1.20g/cm
3The 0.1C specific discharge capacity is 156mAh/g in the time of 25 ℃, and the loading capacity of 0.1C is 112mAh/g in the time of-30 ℃, is equivalent to 71% of normal temperature loading capacity.300 capability retentions of 1C circulation are 98.5% in the time of 25 ℃.
Comparative example 1
This Comparative Examples is used to explain the reference method of preparation LiFePO 4.
The feed way of reaction raw materials liquid among the embodiment 1 is become adding alkali solution B in reaction kettle earlier, add acid liquid A again, other is constant.The color of gained presoma is a lead; Gradually become brick-red in the washing process; Explanation is under this kind feed way; Ferrous iron in the raw material can not all participate in generating the reaction of LiFePO 4, but hydrolysis has generated the hydroxide iron contamination under high pH value, and this impurity is oxidized in air to become ferric impurity.Chemical property is seen table 1.
Comparative example 2
This Comparative Examples is used to explain the reference method of preparation LiFePO 4.
The feed way of reaction raw materials liquid among the embodiment 1 is become adding alkali solution A in reaction kettle earlier, add acid liquid B again, feeding quantity is constant.Earlier acidic aqueous solution A is all added retort, to remove air wherein, start stirring with the nitrogen purging retort, the feed rate adding alkaline aqueous solution B with 8L/min behind reinforced the end, stirred 30 minutes, did not carry out the pH value of reaction system and regulated.Be warmed up to 150 ℃, and continued stirring reaction 8 hours, generate white depositions.After the filtration, with identical wash water washing, sulphate content is 1.2% (with respect to dry material).Other treating processes is identical with embodiment 1.Chemical property is seen table 1.
Comparative example 3
This Comparative Examples is used to explain the reference method of preparation LiFePO 4.
With the quantitative change of the reaction raw materials phosphoric acid among the embodiment 1 is 11.50kg (100mol), and other is constant.The pattern of gained presoma is identical with embodiment 1.Chemical property is seen table 1.To cross that I haven't seen you for ages and cause in the presoma phosphorus not enough for phosphorus during batching, the product that can not obtain having the good electric chemical property.
Comparative example 4
This Comparative Examples is used to explain the reference method of preparation LiFePO 4.
With the quantitative change of the reaction raw materials phosphoric acid among the embodiment 1 is 12.86kg (112mol), and the pH value of reaction system is 7.The pattern of gained presoma is identical with embodiment 1.Chemical property is seen table 1.Because phosphorus is too much in the batching, causes existing in the presoma lithium hydrogen phosphate or Trilithium phosphate, this is an inactive substance, can reduce the chemical property of material.Chemical property is seen table 1.
Embodiment 2
Present embodiment is used to explain the preparation of LiFePO 4 provided by the invention.
(1) take by weighing ferrous sulfate (the ferrous 99.55 weight % of sulfur acid) 55.86kg (200mol), monometallic (mass percent concentration is 98.32%) 23.04kg (218mol), at room temperature; Elder generation's water is with the monometallic dissolving and be diluted to 100L; Again it is added in the ferrous sulfate, stirring and dissolving, and in this solution, add 50g xitix powder; Add water to 120L, obtain containing the acidic aqueous solution A in source of iron and phosphorus source; It is water-soluble to take by weighing 16kg Lithium Hydroxide Monohydrate (99.98%), and is diluted to 80L, obtains containing the alkaline aqueous solution B of lithium salts.Prepare the pH value regulator of the ammoniacal liquor of 20g/L as reaction system in addition, this is a solution C.
(2) earlier with the nitrogen purging retort to remove air wherein; Start stirring; Add said acidic aqueous solution A, said alkaline aqueous solution B simultaneously; The feed rate of A liquid be 4L/min (the reinforced volume of the said liquid flow of PM be the aqueous solution to be added TV 1/30); The feed rate of B liquid be 2.6L/min (the reinforced volume of the said liquid flow of PM be the aqueous solution to be added TV 1/30) behind reinforced the end, stirred 30 minutes, the pH value of use small volume of solution C conditioned reaction system is 8.0.Then, the confined reaction jar is warmed up to 180 ℃, and continues stirring reaction 4 hours.Pressure in the retort comes from the autogenous pressure of water vapor, reach 180 ℃ after, pressure is 1.00Mpa.After reaction finishes, be cooled to below 80 ℃, filter, wash to sulphate content less than 0.5 weight % (with respect to dry material), filter cake 63.6kg, be 50.3% through measuring its solid content, promptly contain amount of solid 32.0kg.
(3) sucrose of adding 5.5kg in above-mentioned filtration gained filter cake thing adds the 55L deionized water again, is mixed with the slurry that solid content is 36 weight %.Dry with centrifugal spray dryer, 350 ℃ of inlet temperatures, 140 ℃ of temperature outs obtain pale powder, and the desciccate that obtains after this spraying drying is warming up to 800 ℃ under nitrogen atmosphere, and the weight loss of keeping after 1.5 hours is 4.8 weight %.It is the intermittent type calcining furnace of 800L that above-mentioned pale powder is placed volume, under argon gas body protection, is warmed up to 350 ℃ with the heat-up rate of 1 ℃/min; Be incubated after 1 hour; Be warmed up to 750 ℃ with same heat-up rate again, and after being incubated 4 hours, naturally cool to below 100 ℃.Obtain ferrous phosphate lithium/carbon composite material.Chemical property is seen table 1.
Comparative example 5
This Comparative Examples is used to explain the reference method of preparation LiFePO 4.
Step (1) is identical with embodiment 2.Middle step 1 products therefrom is dried to constant weight in 120 ℃ in Vacuumdrier, desciccate 32.8kg, mix with 4.5kg glucose again after pulverizing with ball mill, mix with micronizer mill is levigate.This mixture is warming up to 800 ℃ under nitrogen atmosphere after, weight loss is 12.1 weight %.It is the intermittent type calcining furnace of 800L that above-mentioned pale powder is placed volume, under argon gas body protection, is warmed up to 350 ℃ with the heat-up rate of 8 ℃/min; Be incubated after 1 hour; Be warmed up to 750 ℃ with same heat-up rate again, and after being incubated 4 hours, naturally cool to below 100 ℃.Obtain ferrous phosphate lithium/carbon composite material.Chemical property is seen table 1.
Embodiment 3
Present embodiment is used to explain the preparation of LiFePO 4 provided by the invention.
(1) take by weighing ferrous sulfate (the ferrous 97.11 weight % of sulfur acid) 42.94kg (150mol), phosphoric acid (mass percent concentration is 85.25%) 17.93kg (156mol), at room temperature; Elder generation's water is diluted to 80L with phosphoric acid; Again it is added in the ferrous sulfate, stirring and dissolving, and in this solution, add 50g xitix powder; Add water to 100L, must contain the acidic aqueous solution A in source of iron and phosphorus source; Take by weighing 18.90kg Lithium Hydroxide Monohydrate (99.98%) and be dissolved in the water under the room temperature, and be diluted to 100L, obtain containing the alkaline aqueous solution B of lithium salts.Prepare the pH value regulator of the Lithium Hydroxide MonoHydrate of 20g/L as reaction system in addition, this is a solution C.
(2) earlier with the nitrogen purging retort to remove air wherein; Start stirring; Add said acidic aqueous solution A, said alkaline aqueous solution B, feed rate be 5L/min (the reinforced volume of the said liquid flow of PM be the aqueous solution to be added TV 1/20), behind reinforced the end; Stirred 30 minutes, using the pH value of small volume of solution C conditioned reaction system is 9.0.Then, be warmed up to 220 ℃ (this moment, corresponding autogenous pressure was 2.2MPa), and continued stirring reaction 4 hours, generate white depositions.Filter, wash to sulphate content less than 0.5 weight % (with respect to dry material), filter cake 48.7kg, be 49.3% through measuring its solid content, promptly contain amount of solid 24.0kg.
(3) resol resin with 1.2kg is dissolved in 5L ethanol, adds in the above-mentioned filtration gained filter cake, adds the 45L deionized water again, is mixed with the slurry that solid content is 35 weight %.Dry with centrifugal spray dryer, 350 ℃ of inlet temperatures, 140 ℃ of temperature outs obtain pale powder, and this desciccate is heated to 800 ℃ under nitrogen atmosphere, and the weight loss of keeping after 2 hours is 1.9 weight %.It is the intermittent type calcining furnace of 800L that above-mentioned pale powder is placed volume, under oxide gas protection, is warmed up to 350 ℃ with the heat-up rate of 2 ℃/min; Be incubated after 1 hour; Be warmed up to 750 ℃ with same heat-up rate again, and after being incubated 4 hours, naturally cool to below 100 ℃.Chemical property is seen table 1.
Table 1
The specific discharge capacity (mAh/g) of ferrous phosphate lithium/carbon composite material under different multiplying
Can find out that from The above results the ferrous phosphate lithium/carbon composite material that adopts method of the present invention to prepare has good electrochemical.Its specific discharge capacity under the 0.2C condition can reach more than the 150mAh/g, and specific discharge capacity can reach more than the 130mAh/g under the 5C condition, is higher than Comparative Examples far away.Drawing abillity and cycle performance are good, and especially low-temperature performance is good, reach more than 70% of normal temperature loading capacity.In addition, the present invention can prepare LiFePO 4 under comparatively gentle reaction conditions, and facility investment is few, and is simple to operate.
Claims (10)
1. the preparation method of a LiFePO 4 is characterized in that, this method comprises the steps:
The aqueous solution liquid flow that (1) will contain source of iron and phosphorus source is mixed with aqueous solution liquid flow mode with cocurrent adding material in inert atmosphere in lithium source; And use the pH value of the mixture that pH value regulator control obtains to be 7-9, the mol ratio of Li: Fe: P is 1.5-3 in said lithium source, source of iron and the phosphorus source: 1: 1.04-1.1, feed in raw material finish after; Be warming up to 150-250 ℃; Under agitation react 4-8 hour, and be cooled to below 80 ℃, filter; Washing precipitation to sulphate content or chloride content obtain lithium iron phosphate precursor less than 0.5 weight %;
(2) lithium iron phosphate precursor that step (1) is obtained mixes with soluble carbon source additive and water, obtains the slurry that solid content is 30-40 weight %, and wherein, the weight ratio of lithium iron phosphate precursor and soluble carbon source additive is 100: 10-20; Said slurry is carried out spraying drying, and spray-dired condition makes the weight loss of desciccate under 800 ℃ that obtains be not more than 5 weight %;
(3) product that step (2) is obtained carries out roasting.
2. method according to claim 1, wherein, said phosphorus source is selected from H
3PO
4, LiH
2PO
4And NH
4H
2PO
4In one or more.
3. method according to claim 1, wherein, said source of iron is selected from FeSO
4And/or FeCl
2
4. method according to claim 1, wherein, said lithium source is LiOH and/or LiH
2PO
4
5. method according to claim 1, wherein, said pH value regulator is Lithium Hydroxide MonoHydrate and/or ammoniacal liquor.
6. method according to claim 1; Wherein, The reinforced volume that PM contains the aqueous solution liquid flow in source of iron and phosphorus source is the 1/10-1/30 of the TV of the aqueous solution to be added, and the reinforced volume of the aqueous solution liquid flow in PM lithium source is the 1/10-1/30 of the TV of the aqueous solution to be added.
7. method according to claim 1, wherein, this method also is included in the step (1), and with xitix powder and the step that contains the aqueous solution in source of iron and phosphorus source, the add-on of said xitix powder is 0.1-0.5g/L.
8. method according to claim 1, wherein, the spraying drying of step (2) is in air atmosphere, to carry out, and the hot gas flow inlet temperature is 300-400 ℃, and temperature out is 100-150 ℃.
9. method according to claim 1, wherein, in the said step (2), the soluble carbon source additive is selected from one or more in Zulkovsky starch, Z 150PH, sucrose, glucose and the resol resin.
10. method according to claim 1, wherein, the condition of the roasting in the step (3) is included under the inert atmosphere, 300-400 ℃ of roasting 1-2 hour and 650-780 ℃ with normal pressure under roasting 4-10 hour.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104752716A (en) * | 2013-12-27 | 2015-07-01 | 比亚迪股份有限公司 | Lithium iron phosphate and its preparation method and use |
| CN104752720A (en) * | 2013-12-30 | 2015-07-01 | 比亚迪股份有限公司 | Lithium manganese ferric phosphate, preparation method and application thereof |
| US20150259208A1 (en) * | 2014-03-14 | 2015-09-17 | Valence Technology, Inc. | Method of Making Active Materials for Use in Secondary Electrochemical Cells |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002083555A2 (en) * | 2001-04-10 | 2002-10-24 | Zentrum Für Sonnenenergie- Und Wasserstoff-Forschung Baden-Württemberg, Gemeinnützige Stiftung | Binary, ternary and quaternary lithium phosphates, method for the production thereof and use of the same |
| CN1903708A (en) * | 2006-08-18 | 2007-01-31 | 河南环宇集团有限公司 | Wet method of preparing lithium ferrous phosphate and its prepared lithium ferrous phosphate |
| CN101442117A (en) * | 2008-12-22 | 2009-05-27 | 上海电力学院 | Method for preparing carbon-coating ferric phosphate lithium |
-
2010
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002083555A2 (en) * | 2001-04-10 | 2002-10-24 | Zentrum Für Sonnenenergie- Und Wasserstoff-Forschung Baden-Württemberg, Gemeinnützige Stiftung | Binary, ternary and quaternary lithium phosphates, method for the production thereof and use of the same |
| CN1903708A (en) * | 2006-08-18 | 2007-01-31 | 河南环宇集团有限公司 | Wet method of preparing lithium ferrous phosphate and its prepared lithium ferrous phosphate |
| CN101442117A (en) * | 2008-12-22 | 2009-05-27 | 上海电力学院 | Method for preparing carbon-coating ferric phosphate lithium |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104752716A (en) * | 2013-12-27 | 2015-07-01 | 比亚迪股份有限公司 | Lithium iron phosphate and its preparation method and use |
| CN104752716B (en) * | 2013-12-27 | 2017-02-15 | 比亚迪股份有限公司 | Lithium iron phosphate and its preparation method and use |
| CN104752720A (en) * | 2013-12-30 | 2015-07-01 | 比亚迪股份有限公司 | Lithium manganese ferric phosphate, preparation method and application thereof |
| CN104752720B (en) * | 2013-12-30 | 2017-12-01 | 比亚迪股份有限公司 | A kind of iron manganese phosphate for lithium and its preparation method and application |
| US20150259208A1 (en) * | 2014-03-14 | 2015-09-17 | Valence Technology, Inc. | Method of Making Active Materials for Use in Secondary Electrochemical Cells |
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