CN102185137A - Preparation method of multilevel-coated multivariate composite lithium iron phosphate cathode material - Google Patents
Preparation method of multilevel-coated multivariate composite lithium iron phosphate cathode material Download PDFInfo
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- CN102185137A CN102185137A CN2011100321653A CN201110032165A CN102185137A CN 102185137 A CN102185137 A CN 102185137A CN 2011100321653 A CN2011100321653 A CN 2011100321653A CN 201110032165 A CN201110032165 A CN 201110032165A CN 102185137 A CN102185137 A CN 102185137A
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- iron phosphate
- preparation
- lithium iron
- composite lithium
- positive electrode
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Abstract
A preparation method of a multilevel-coated multivariate composite lithium iron phosphate cathode material relates to a lithium ion battery cathode material. The method comprises the following steps: feeding main raw materials of Fe(OH)3, Li2CO3, NH4H2PO4 and oxide doped with metal ions into a ball mill according to a stoichiometric ratio, adding deionized water and zirconium balls as milling media; performing ball milling, drying, and sieving; sintering the dried materials in argon atmosphere; sieving the primary sintered materials after calcination, adding polymer organic carbon source for carbon coating for the second time, adding deionized water, performing ball milling and drying; sintering all the materials in argon atmosphere, cooling to obtain a multilevel-coated multivariate composite lithium iron phosphate cathode material. The preparation process is stable; the steps are simple; especially the product reproducibility is good; and industrial production is quite easy to realize.
Description
Technical field
The present invention relates to a kind of anode material for lithium-ion batteries, especially relate to the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating.
Background technology
The LiFePO of olivine-type structure
4Have environmentally friendly, the energy density height, You Yi cycle performance especially, best remarkable advantages such as security performance, and its synthesis material aboundresources, cheap, by consistent being known as is to make high safety, low cost, the best positive electrode of long-life power lithium-ion battery, be one of new energy materials of tool potentiality, become the manufacturing object of pursuing of battery industry and new energy materials.But LiFePO4 exists the defective of the character of material own: conductance is low, and high rate performance is poor, and this has limited its extensive use in practical field greatly; And preparation process relative complex (raw material type is many, the difficult mixing); Synthesis condition is harsh (inert gas shielding) comparatively; To atmosphere, equipment requirements higher (good air-tightness will be arranged), this has just further limited its large-scale industrialization.
Chinese patent CN101521276 discloses a kind of preparation method of lithium ion battery positive material coated with carbon: the certain amount of lithium ion battery positive powder is put into polyacrylonitrile solution; abundant stirring and evenly mixing; behind the heating evaporation solvent; under air atmosphere; put into baking oven and heat 2～4h down at 150～300 ℃; obtain black solid; again the black solid of gained is put into high temperature furnace; 400～1200 ℃ of heating 0.5～4h just obtain the lithium ion battery powdery positive electrode that the surface has coated carbon under inert gas shielding.
Chinese patent CN101521278 discloses a kind of anode composite material of lithium ion battery preparation method, adopts high-temperature decomposition to prepare δ-MnO
2Adopt ion implantation to prepare composite material δ-MnO
2-X, wherein X is a transition metal, with the δ-MnO that makes
2With the sheet is matrix, then the implanting transition metal ion; Composite material is made battery anode slice; Scrape δ-MnO that the top layer forms
2-X make positive electrode active materials and mix in proportion with other material and through film, drying, compressing tablet, step such as dry, weigh make based lithium-ion battery positive plate.Owing to adopt ion implantation technique, inject a certain amount of transition metal ions in the table of layered manganese oxide, make the layered manganese oxide modification, strengthen lithium ion and embed/deviate from ability in the electrochemistry of this material, improve stratiform MnO
2Specific discharge capacity, the lithium ion battery of making has that cost is low, performance good, the advantage of environmental protection.
Summary of the invention
The preparation method who the purpose of this invention is to provide the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating.
The polynary composite lithium iron phosphate positive electrode of described multi-level coating is LiM
xFe
1-xPO
4/ C composite material.
The present invention includes following steps:
1) with main material Fe (OH)
3, Li
2CO
3, NH
4H
2PO
4Join in the ball mill according to stoichiometric proportion with the oxide of doped metal ion M, add deionized water and zirconium ball and do abrasive media, behind the ball milling, drying is sieved;
In step 1), the amount of described adding deionized water can be main material Fe (OH)
3, Li
2CO
3, NH
4H
2PO
4With 30%～50% of the oxide aggregate of doped metal ion M, the time of described ball milling can be 3～5h, and described drying can adopt spray drying; The oxide of described doped metal ion M can be selected from TiO
2, Nb
2O
5Or MnO
2Deng.
2) dried material is calcined under argon shield;
In step 2) in, described calcining can be calcined 3～5h under 350～500 ℃ in tube furnace.
3) primary sintered material after will calcining sieves, and adds the macromolecule organic carbon source and carries out second time charcoal and coat, and adds deionized water again, drying behind the ball milling;
In step 3), the described amount that adds deionized water again can be 30%～40% of primary sintered material; The ball material mass ratio of described ball milling can be (4～8): 1, and the time of described ball milling can be 3～5h, and described drying can adopt spray drying; Described macromolecule organic carbon source can be selected from glucose, sucrose, citric acid or polyethylene glycol etc.
4), promptly get after the cooling and coat polynary composite lithium iron phosphate positive electrode at many levels with step 3) gained material sintering under argon atmosphere.
In step 4), described sintering, can be in tube furnace 600～800 ℃ of following sintering 12～16h.
The invention has the advantages that in building-up process, except passing through doped metal ion (Ti
4+, Nb
5+And Mn
4+), replace a spot of iron in the LiFePO4 with outside the conductivity that improves LiFePO 4 material, most importantly adopt by twice batching, the different carbon sources of twice adding, especially for the second time batching adds the macromolecule organic carbon source, to the method that twice carbon of LiFePO 4 material coats, improves LiM
xFe
1-xPO
4The conductivity of/C composite material; Further improve its big multiplying power and charge and discharge electric energy.Through facts have proved that this process is feasible, effect is remarkable: the LiM that adopts preparation technology of the present invention to produce
xFe
1-xPO
4/ C composite material, phosphorus content be 2%～5%, and tap density is at 0.8-1.3g/ml, make battery after, internal resistance is less than 30m Ω, its capacity of electrochemical property test 1C reaches 115～130mAh/g, and the cycle performance excellence, 800 weeks are unattenuated; The big advantage of another of this invention is exactly the sintering stable preparation process that repeatedly coats of the present invention, and step is simple relatively, and particularly the product reappearance is good, is very easy to realize industrialization production.
Description of drawings
Fig. 1 is the LiM of preparation
xFe
1-xPO
4The laser particle size distribution map of/C composite material.In Fig. 1, abscissa is granularity (μ m), and ordinate is distributive law (%).
Fig. 2 is the LiM of preparation
xFe
1-xPO
4The SEM figure of/C composite material.
Fig. 3 is the LiM of preparation
xFe
1-xPO
4The discharge cycles curve (1C) of/C composite material.In Fig. 3, abscissa is a cycle-index, and ordinate is a discharge capacity.
Fig. 4 is the LiM of preparation
xFe
1-xPO
4The XRD figure of/C composite material.In Fig. 4, abscissa be angle of diffraction 2-Theta (°), ordinate is diffracted intensity Intensity (CPS); Respectively composing the peak from left to right is: d=5.1691,2T=17.140,40.0%; D=4.2753,2T=20.760,88.8%; D=3.9175,2T=22.680,28.3%; D=3.7012,2T=24.024,10.8%; D=3.4821,2T=25.560,99.4%; D=3.0053,2T=29.702,91.6%; D=2.7774,2T=32.203,33.6%; D=2.5985,2T=34.487,2.0%; D=2.5198,2T=35.599,100.0%; D=2.4571,2T=36.539,30.6%; D=2.3730,2T=37.883,19.6%; D=2.2892,2T=39.326,14.3%; D=2.2630,2T=39.799,23.1%; D=2.1368,2T=42.260,18.5%; D=2.0366,2T=44.401,6.2%; D=2.0129,2T=44.998,4.4%; D=1.9586,2T=46.319,2.0%; D=1.8490,2T=49.239,10.3%; D=1.8132,2T=50.280,11.0%; D=1.7404,2T=52.539,26.4%; D=1.6682,2T=55.000,13.4%; D=1.6544,2T=55.498,14.1%; D=1.6242,2T=56.621,17.6%; D=1.5819,2T=58.276,8.8%; D=1.4982,2T=61.880,18.0%; D=1.4530,2T=64.026,2.9%; D=1.4075,2T=66.359,4.8%; D=1.3854,2T=57.560,4.4%; D=1.3399,2T=70.182,7.7%; Wherein d is an interplanar distance, and 2T is the angle of diffraction.
Embodiment
With 4.0mol Fe (OH)
3, 2.1mol Li
2CO
3, 4mol NH
4H
2PO
4, 0.02mol TiO
2, 0.02mol MnO
2, add in the ball mill, add 1.5L deionized water and abrasive media zirconium ball (ratio of grinding media to material 8: 1) again, rotating speed is 40Hz, 5 h of ball milling after making the raw material porphyrize and mixing, carry out spray drying, sieve; Under argon shield, the heating rate with 5 ℃/min in tube furnace rises to 350 ℃, constant temperature 5h with the material after the spray drying; Primary sintered material is crossed 100 mesh sieves, add the 200g polyethylene glycol, 1 deionized water and abrasive media zirconium ball (ratio of grinding media to material 6: 1), rotating speed is 30Hz, ball milling 3h is fully permeated primary sintered material and coats, and carries out spray drying, sieves; With the material that the second time, carbon coated, continue under the protection of argon gas, to be put in the tube furnace, rise to 700 ℃ with the heating rate of 5 ℃/min, constant temperature 12h is cooled to room temperature, and 200 eye mesh screens are crossed in back discharging must finished product.Products obtained therefrom, tap density are 0.95g/ml, and phosphorus content is 2.79%, makes battery, and the 1C discharge capacity is 125mAh/g.
With 4.0mol Fe (OH)
3, 2.05mol Li
2CO
3, 4mol NH
4H
2PO
4, 0.02mol TiO
2, 0.01mol Nb
2O
5, add in the ball mill, add 1.5L deionized water and abrasive media zirconium ball (ratio of grinding media to material 8: 1) again, rotating speed is 40Hz, 5 h of ball milling after making the raw material porphyrize and mixing, carry out spray drying, sieve; Under argon shield, the heating rate with 5 ℃/min in tube furnace rises to 350 ℃, constant temperature 5h with the material after the spray drying; Primary sintered material is sieved, add the 250g polyethylene glycol, 1 deionized water and abrasive media zirconium ball (ratio of grinding media to material 6: 1), rotating speed is 40Hz, ball milling 2h is fully permeated primary sintered material and coats, and carries out spray drying, sieves; With the material that the second time, carbon coated, continue under the protection of argon gas, to be put in the tube furnace, rise to 700 ℃ with the heating rate of 5 ℃/min, constant temperature 12h is cooled to room temperature, and 200 eye mesh screens are crossed in back discharging must finished product.Products obtained therefrom, tap density are 0.88g/ml, and phosphorus content is 3.12%, makes battery, and the 1C discharge capacity is 138mAh/g.
With 4.0mol Fe (OH)
3, 2.05mol Li
2CO
3, 4mol NH
4H
2PO
4, 0.01mol TiO
2, 0.02mol Nb
2O
5, 0.01mol MnO
2, add in the ball mill, add 1.5L deionized water and abrasive media zirconium ball (ratio of grinding media to material 8: 1) again, rotating speed is 50Hz, ball milling 3h after making the raw material porphyrize and mixing, carries out spray drying, sieves; Under argon shield, the heating rate with 5 ℃/min in tube furnace rises to 350 ℃, constant temperature 5h with the material after the spray drying; Primary sintered material is sieved, add the 250g polyethylene glycol, 1L deionized water and abrasive media zirconium ball (ratio of grinding media to material 6: 1), rotating speed is 40Hz, ball milling 2h is fully permeated primary sintered material and coats, and carries out spray drying, sieves; With the material that the second time, carbon coated, continue under the protection of argon gas, to be put in the tube furnace, rise to 750 ℃ with the heating rate of 5 ℃/min, constant temperature 16h is cooled to room temperature, and 200 eye mesh screens are crossed in back discharging must finished product.Products obtained therefrom, tap density are 1.02g/ml, and phosphorus content is 3.02%, makes battery, and the 1C discharge capacity is 131mAh/g.
Prepared LiM
xFe
1-xPO
4The laser particle size distribution map of/C composite material is referring to Fig. 1, prepared LiM
xFe
1-xPO
4The SEM figure of/C composite material is referring to Fig. 2, prepared LiM
xFe
1-xPO
4The discharge cycles curve (1C) of/C composite material is referring to Fig. 3, prepared LiM
xFe
1-xPO
4The XRD figure of/C composite material is referring to Fig. 4.
Claims (10)
1. multi-level preparation method who coats polynary composite lithium iron phosphate positive electrode is characterized in that may further comprise the steps:
1) with main material Fe (OH)
3, Li
2CO
3, NH
4H
2PO
4Join in the ball mill according to stoichiometric proportion with the oxide of doped metal ion M, add deionized water and zirconium ball and do abrasive media, behind the ball milling, drying is sieved;
2) dried material is calcined under argon shield;
3) primary sintered material after will calcining sieves, and adds the macromolecule organic carbon source and carries out second time charcoal and coat, and adds deionized water again, drying behind the ball milling;
4), promptly get after the cooling and coat polynary composite lithium iron phosphate positive electrode at many levels with step 3) gained material sintering under argon atmosphere.
2. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 1) the amount of described adding deionized water is main material Fe (OH)
3, Li
2CO
3, NH
4H
2PO
4With 30%～50% of the oxide aggregate of doped metal ion M.
3. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 1) the time of described ball milling is 3～5h; Described drying is to adopt spray drying.
4. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 1) the oxide of described doped metal ion M is selected from TiO
2, Nb
2O
5Or MnO
2
5. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 2) in, described calcining is to calcine 3～5h in tube furnace under 350～500 ℃.
6. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 3) the described amount that adds deionized water again is 30%～40% of a primary sintered material.
7. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 3) the ball material mass ratio of described ball milling is 4～8: 1.
8. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 3) the time of described ball milling is 3～5h; Described drying is to adopt spray drying.
9. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 3) described macromolecule organic carbon source is selected from glucose, sucrose, citric acid or polyethylene glycol.
10. the preparation method of the polynary composite lithium iron phosphate positive electrode of a kind of multi-level coating as claimed in claim 1 is characterized in that in step 4), and described sintering is 600～800 ℃ of following sintering 12～16h in tube furnace.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103247778A (en) * | 2013-04-26 | 2013-08-14 | 北大先行科技产业有限公司 | High-power lithium iron phosphate positive pole material and manufacturing method thereof |
| CN106207170A (en) * | 2016-08-15 | 2016-12-07 | 海宁永欣科技咨询有限公司 | A kind of production technology of nanometer lithium iron phosphate cathode material |
| CN114927655A (en) * | 2022-04-29 | 2022-08-19 | 山东昭文新能源科技有限公司 | Multilayer coated lithium iron phosphate electrode material and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103247778A (en) * | 2013-04-26 | 2013-08-14 | 北大先行科技产业有限公司 | High-power lithium iron phosphate positive pole material and manufacturing method thereof |
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| CN114927655A (en) * | 2022-04-29 | 2022-08-19 | 山东昭文新能源科技有限公司 | Multilayer coated lithium iron phosphate electrode material and preparation method and application thereof |
| CN114927655B (en) * | 2022-04-29 | 2023-12-05 | 山东昭文新能源科技有限公司 | Multilayer coated lithium iron phosphate electrode material and preparation method and application thereof |
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Application publication date: 20110914 |