CN118083937A - Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application - Google Patents
Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application Download PDFInfo
- Publication number
- CN118083937A CN118083937A CN202410210193.7A CN202410210193A CN118083937A CN 118083937 A CN118083937 A CN 118083937A CN 202410210193 A CN202410210193 A CN 202410210193A CN 118083937 A CN118083937 A CN 118083937A
- Authority
- CN
- China
- Prior art keywords
- manganese
- iron
- source
- carbon
- phosphate precursor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002243 precursor Substances 0.000 title claims abstract description 89
- AWKHTBXFNVGFRX-UHFFFAOYSA-K iron(2+);manganese(2+);phosphate Chemical compound [Mn+2].[Fe+2].[O-]P([O-])([O-])=O AWKHTBXFNVGFRX-UHFFFAOYSA-K 0.000 title claims abstract description 75
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 title claims abstract description 28
- 239000007774 positive electrode material Substances 0.000 title claims abstract description 27
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 93
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 77
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 77
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 75
- 230000003247 decreasing effect Effects 0.000 claims abstract description 14
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 9
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 60
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 26
- 239000008103 glucose Substances 0.000 claims description 26
- 238000002156 mixing Methods 0.000 claims description 25
- 229910052742 iron Inorganic materials 0.000 claims description 24
- 239000011572 manganese Substances 0.000 claims description 24
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 claims description 24
- 229910052748 manganese Inorganic materials 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 239000002245 particle Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 15
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 11
- 229910052744 lithium Inorganic materials 0.000 claims description 11
- 239000002202 Polyethylene glycol Substances 0.000 claims description 10
- 239000008139 complexing agent Substances 0.000 claims description 10
- 239000002270 dispersing agent Substances 0.000 claims description 10
- 229920001223 polyethylene glycol Polymers 0.000 claims description 10
- 229940116007 ferrous phosphate Drugs 0.000 claims description 7
- 229910000155 iron(II) phosphate Inorganic materials 0.000 claims description 7
- SDEKDNPYZOERBP-UHFFFAOYSA-H iron(ii) phosphate Chemical compound [Fe+2].[Fe+2].[Fe+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O SDEKDNPYZOERBP-UHFFFAOYSA-H 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 230000032683 aging Effects 0.000 claims description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 239000011574 phosphorus Substances 0.000 claims description 5
- 229910019142 PO4 Inorganic materials 0.000 claims description 4
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 4
- 235000006748 manganese carbonate Nutrition 0.000 claims description 4
- 239000011656 manganese carbonate Substances 0.000 claims description 4
- 229940093474 manganese carbonate Drugs 0.000 claims description 4
- 229940099596 manganese sulfate Drugs 0.000 claims description 4
- 235000007079 manganese sulphate Nutrition 0.000 claims description 4
- 239000011702 manganese sulphate Substances 0.000 claims description 4
- 229910000016 manganese(II) carbonate Inorganic materials 0.000 claims description 4
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 claims description 4
- XMWCXZJXESXBBY-UHFFFAOYSA-L manganese(ii) carbonate Chemical compound [Mn+2].[O-]C([O-])=O XMWCXZJXESXBBY-UHFFFAOYSA-L 0.000 claims description 4
- GEVPUGOOGXGPIO-UHFFFAOYSA-N oxalic acid;dihydrate Chemical compound O.O.OC(=O)C(O)=O GEVPUGOOGXGPIO-UHFFFAOYSA-N 0.000 claims description 4
- 238000005245 sintering Methods 0.000 claims description 4
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 3
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 claims description 3
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 3
- 239000010452 phosphate Substances 0.000 claims description 3
- HMFHBZSHGGEWLO-SOOFDHNKSA-N D-ribofuranose Chemical compound OC[C@H]1OC(O)[C@H](O)[C@@H]1O HMFHBZSHGGEWLO-SOOFDHNKSA-N 0.000 claims description 2
- 229930091371 Fructose Natural products 0.000 claims description 2
- RFSUNEUAIZKAJO-ARQDHWQXSA-N Fructose Chemical compound OC[C@H]1O[C@](O)(CO)[C@@H](O)[C@@H]1O RFSUNEUAIZKAJO-ARQDHWQXSA-N 0.000 claims description 2
- 239000005715 Fructose Substances 0.000 claims description 2
- PYMYPHUHKUWMLA-LMVFSUKVSA-N Ribose Natural products OC[C@@H](O)[C@@H](O)[C@@H](O)C=O PYMYPHUHKUWMLA-LMVFSUKVSA-N 0.000 claims description 2
- HMFHBZSHGGEWLO-UHFFFAOYSA-N alpha-D-Furanose-Ribose Natural products OCC1OC(O)C(O)C1O HMFHBZSHGGEWLO-UHFFFAOYSA-N 0.000 claims description 2
- 229920002401 polyacrylamide Polymers 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- 238000009826 distribution Methods 0.000 abstract description 8
- 238000004090 dissolution Methods 0.000 abstract description 3
- 230000002195 synergetic effect Effects 0.000 abstract description 3
- 239000010405 anode material Substances 0.000 description 15
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 12
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 12
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 12
- 235000019837 monoammonium phosphate Nutrition 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 11
- 229910052808 lithium carbonate Inorganic materials 0.000 description 11
- 239000012299 nitrogen atmosphere Substances 0.000 description 10
- 238000001694 spray drying Methods 0.000 description 10
- 238000001816 cooling Methods 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 238000011282 treatment Methods 0.000 description 9
- 238000001035 drying Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- 238000001914 filtration Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000002386 leaching Methods 0.000 description 4
- 238000013508 migration Methods 0.000 description 4
- 230000005012 migration Effects 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 229910018663 Mn O Inorganic materials 0.000 description 2
- 229910003176 Mn-O Inorganic materials 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000006230 acetylene black Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
- TYTHZVVGVFAQHF-UHFFFAOYSA-N manganese(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Mn+3].[Mn+3] TYTHZVVGVFAQHF-UHFFFAOYSA-N 0.000 description 2
- GEYXPJBPASPPLI-UHFFFAOYSA-N manganese(III) oxide Inorganic materials O=[Mn]O[Mn]=O GEYXPJBPASPPLI-UHFFFAOYSA-N 0.000 description 2
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 2
- 239000006012 monoammonium phosphate Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 229910015645 LiMn Inorganic materials 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Inorganic materials [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 description 1
- 238000007709 nanocrystallization Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention relates to the field of lithium ion batteries, in particular to a manganese iron phosphate precursor, a manganese iron lithium phosphate positive electrode material, a preparation method and application; the manganese iron phosphate precursor comprises manganese element, iron element and carbon element; from the inner core to the surface, the content of manganese element is decreased progressively, the content of iron element is increased progressively, and the content of carbon element is decreased progressively; the contents of the three elements show gradient distribution synergistic effect, and the battery containing the lithium iron manganese phosphate positive electrode material prepared from the precursor can give consideration to higher discharge gram capacity and discharge platform voltage, and the dissolution amount of manganese element is reduced.
Description
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a manganese iron phosphate precursor, a manganese iron lithium phosphate positive electrode material, a preparation method and application.
Background
Lithium iron phosphate (LiMn xFe1-xPO4, abbreviated as LMFP) is a positive electrode material of a lithium ion battery, and gradually becomes a further selection for replacing lithium iron phosphate by virtue of the advantages of high safety performance, long cycle life, high voltage, wide raw material sources and the like, and becomes an important selection for new energy automobiles and energy storage markets in the future.
However, lithium iron manganese phosphate also has problems of poor electron conductivity, manganese elution, and the like, because in a nonlinear MnO 6 octahedron, mn 3+ in a high spin state has a very large magnetic moment, and only one electron exists in a double degenerate eg orbit (including dx 2-y2 and dz 2 orbitals), resulting in an asymmetric distribution of electrons. Meanwhile, electrons in dx 2-y2 and dz 2 orbitals show different degrees of shielding effect on Mn nuclei in different directions, and in order to stabilize Mn 3+ migration in molecules, longitudinal Mn-O bonds are gradually elongated, and horizontal Mn-O bonds are shortened, so that linear MnO 2 alignment is elongated along the axial direction, and Jahn-Teller distortion is generated. Jahn-Teller distortion will bring severe structural changes to the material, accelerate the destruction of the material structure, and cause the inactivation of the material; in order to avoid Jahn-Teller distortion, the material can be modified to improve the performance, and the modification process comprises carbon coating, particle size nanocrystallization, ion doping, manganese content optimization and other processes.
However, the current technology has the following problems: the conductivity of the material is obviously reduced due to the introduction of the manganese element, and meanwhile, the problem of manganese element dissolution can occur.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defect that the battery in the prior art cannot achieve both higher discharge gram capacity and discharge platform voltage, and the manganese element in the battery can be dissolved out, so as to provide a manganese iron phosphate precursor, a manganese iron lithium phosphate anode material, a preparation method and application.
Therefore, the invention provides the following technical scheme:
The first aspect of the invention provides a manganese iron phosphate precursor, which comprises manganese element, iron element and carbon element; wherein, from the inner core to the surface, the content of manganese element is decreased, the content of iron element is increased, and the content of carbon element is decreased.
According to the manganese iron phosphate precursor provided by the invention, from the inner core to the surface, the content of manganese element is reduced, the content of iron element is increased, the content of carbon element is reduced, and a battery containing the manganese iron phosphate lithium anode material prepared from the manganese iron phosphate precursor can give consideration to higher discharge gram capacity and discharge platform voltage; the gradient distribution of the carbon content enhances the electronic conductivity, promotes the migration and diffusion of lithium ions and improves the conductivity of the battery.
According to the invention, the molar ratio of manganese element to iron element at the core is (8-9): (1-2).
According to the invention, the content of the carbon element is 5-8wt% based on the mass of the manganese iron phosphate precursor at the core.
According to the invention, the molar ratio of manganese element to iron element is (6-7.5) (2.2-4) in the middle of the core and the surface.
According to the invention, the content of carbon element is 2-4wt% based on the mass of the manganese iron phosphate precursor in the middle of the core and the surface.
According to the invention, the molar ratio of manganese element to iron element at the surface is (3-5): (5-7).
According to the invention, the content of carbon element is 1-2wt% based on the mass of the manganese iron phosphate precursor at the surface.
In the invention, the average particle size of the manganese iron phosphate precursor is 0-1.8 mu m at the inner core, the average particle size of the manganese iron phosphate precursor is 1.8-2.5 mu m (excluding 1.8 mu m) at the middle between the inner core and the surface, and the average particle size of the manganese iron phosphate precursor is 2.5-5 mu m (excluding 2.5 mu m) at the surface.
In the invention, the content of different metal elements at different parts of the manganese iron phosphate precursor is determined by adopting an ICP method, and the specific method comprises the following steps: 1g of the sample was digested by adding it to 20mL of hydrochloric acid solution (37 wt% hydrochloric acid: pure water=1:1), the liquid sample was pumped into the plasma torch by the atomizer, the sample was excited, the characteristic spectrum of the emitted element was reflected by a mirror, and then focused on the entrance slit of the spectrometer. When light enters the spectrometer, the light is emitted to the grating, and diffracted light irradiates the photosensitive cathode of the photomultiplier through the exit slit according to the analysis wavelength. The light corresponding to each sample is converted to electrical energy and the computer directly converts the signal intensity to the corresponding sample concentration and records the reading.
In the invention, a carbon-sulfur analyzer is used for measuring the content of carbon, and the specific method is that a sample is oxidized by oxygen at high temperature of a combustion furnace, is introduced into a carbon detection tank for measuring carbon, and is read on a computer.
According to the invention, the average particle size of the ferric manganese phosphate precursor is 3-5 μm.
The second aspect of the invention provides a method for preparing a manganese iron phosphate precursor, comprising the following steps:
step 1, mixing a first manganese source, a first iron source, a first phosphorus source and a first carbon source to obtain a base solution;
Step 2, adding a manganese source solution, an iron source solution, a carbon source solution and a complexing agent into the base solution at an initial flow rate to perform a reaction, and respectively reducing the flow rates of the manganese source solution and the carbon source solution to 2/3-9/10 of the initial flow rates when the average particle size of the reaction reaches 1.5-2 mu m; increasing the flow rate of the iron source solution to 2-4 times of the initial flow rate;
when the reaction is carried out until the average particle size is 2.5-2.8 mu m, respectively reducing the flow rate of the manganese source solution and the flow rate of the carbon source solution to 1/3-3/4 of the initial flow rate; increasing the flow rate of the iron source solution to 3-7 times of the initial flow rate;
And step 3, ageing the material obtained after the reaction in the step 2, and separating to obtain a manganese iron phosphate precursor.
In the invention, a step-by-step preparation mode is adopted, and a base solution is obtained first; and then, through the regulation and control of the multistage flow rate, the content of manganese element is decreased progressively, the content of iron element is increased progressively and the content of carbon element is decreased progressively from the inner core to the surface in the prepared manganese iron phosphate precursor, so that the gradient distribution state is presented, and finally, the electric conductivity of the battery containing the positive electrode material prepared from the precursor is excellent, and the dissolution amount of manganese element is reduced.
In step 3 of the present invention, the separation is carried out in a manner conventional in the art, typically without limitation, the separation comprising: filtering, washing and drying; the conditions of washing and drying are not limited, and pure and dry manganese iron phosphate precursor can be obtained.
According to the invention, in step 1, the molar ratio of the first manganese source, the first iron source, the first phosphorus source and the first carbon source is (5-10): (0.5-2): (5-12): 1, preferably (8-9): (1-1.5): (9-10): 1.
According to the invention, in step 1, a dispersing agent is also added before mixing.
According to the invention, the mass ratio of the dispersing agent to the first iron source is 8-12:1.
According to the invention, the dispersant comprises polyethylene glycol and/or polyacrylamide.
According to the invention, in step 2, the molar ratio of the complexing agent to the first iron source is between 0.3 and 0.6:1.
According to the invention, in step 2, the complexing agent comprises ferrous phosphate and/or oxalic acid dihydrate.
According to the invention, in the step 2, the manganese source solution comprises a second manganese source and water, wherein the concentration of the second manganese source is 1.8-2.2mol/L.
According to the invention, in the step 2, the iron source solution comprises a second iron source and water, wherein the concentration of the second iron source is 0.7-1.3mol/L.
According to the invention, in the step 2, the carbon source solution contains a second carbon source and water, wherein the concentration of the second carbon source is 0.3-0.5g/L.
According to the present invention, the first manganese source and the second manganese source are each independently selected from at least one of manganese nitrate, manganese sulfate, and manganese carbonate.
According to the present invention, the first iron source and the second iron source are each independently selected from at least one of ferric nitrate, manganese sulfate, and manganese carbonate.
According to the present invention, the first carbon source and the second carbon source are each independently selected from at least one of glucose, fructose, and ribose.
In the present invention, the mixing conditions in step 1 are conventional in the art, and the mixing conditions are not limited and can be uniformly mixed.
According to the invention, in step 2, the initial flow rate is between 0.005 and 0.1L/s.
According to the invention, the reaction conditions include: the reaction temperature is 50-80 ℃.
The third aspect of the invention protects a manganese iron phosphate precursor prepared by the preparation method.
The fourth aspect of the invention provides a lithium iron manganese phosphate positive electrode material, wherein the lithium iron manganese phosphate positive electrode material is prepared by sintering a lithium source and the precursor of the lithium iron manganese phosphate.
According to the invention, the molar ratio of the lithium source to the manganese iron phosphate precursor is 0.5-1.2:1.
In the invention, the lithium source adopted in the preparation process comprises at least one of lithium carbonate, lithium sulfate and lithium nitrate.
In the present invention, the manganese iron phosphate precursor and the lithium source are mixed before sintering, and the mixing mode of the manganese iron phosphate precursor and the lithium source is a conventional mixing mode in the field, typically, but not limited to, the mixing mode comprises the following steps: mixing a ferric manganese phosphate precursor with a lithium source and water, performing sanding treatment, and then performing spray drying; the amount of water is conventional in the art and typically, without limitation, the ratio of the lithium source to the water is (250-300): (0.5-0.7) in g: mol.
In the invention, the sintering condition is conventional in the field, and typically, but not limited to, under the protection of N 2, the temperature is raised to 800-900 ℃ at the speed of 1-2 ℃/min, and the temperature is kept for 8-10 hours, so as to obtain the lithium iron manganese phosphate anode material.
The fifth aspect of the invention provides an application of the lithium manganese iron phosphate anode material in a lithium ion battery.
In the invention, the composition and the preparation method of the provided lithium ion battery are all conventional in the field. Typically, without limitation, the composition and preparation method of the positive electrode sheet includes: mixing the anode material with conductive agent acetylene black and binder PVDF according to the mass ratio of 90:5:5, adding 3-5g of 1-methyl-2 pyrrolidone, ball milling for 1h to prepare slurry, uniformly coating the slurry on an aluminum sheet, and drying and tabletting to prepare the anode sheet. The composition and preparation method of the negative electrode plate comprise the following steps: taking a metal lithium sheet as a negative electrode; the 2032 button cell is assembled, the blue electric testing system is adopted for electric performance testing, the charge and discharge voltage is 2.0-4.2V, the first circle is charged and discharged at 0.1C/0.1C, and then the cycle is 200 circles at 1C/1C.
The technical scheme of the invention has the following advantages:
1. The invention provides a manganese iron phosphate precursor, wherein from an inner core to a surface, the content of manganese element is decreased, the content of iron element is increased, and the content of carbon element is decreased; the contents of the three elements show gradient distribution and synergistic effect, and the battery containing the lithium iron manganese phosphate positive electrode material prepared from the precursor can give consideration to higher discharge gram capacity and discharge platform voltage, so that the leaching amount of manganese element is reduced; further, the gradient distribution of the carbon content enhances the electronic conductivity, promotes the migration and diffusion of lithium ions, and improves the conductivity of the battery.
2. According to the invention, by a stepwise preparation method, a base solution is prepared, wherein the base solution comprises manganese element, iron element, phosphorus element and carbon element; then manganese element, iron element and carbon element are added again in a mode of regulating and controlling the multistage flow velocity; the two steps cooperate to enable the contents of manganese element, iron element and carbon element in the prepared manganese iron phosphate precursor to be distributed in a gradient way, the contents of manganese element are decreased progressively, the contents of iron element are increased progressively and the contents of carbon element are decreased progressively from the inner core to the surface, and the battery containing the manganese iron lithium phosphate positive electrode material prepared from the precursor can give consideration to higher discharge gram capacity and discharge platform voltage and the quantity of manganese element dissolved out is reduced.
Detailed Description
The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the invention, any product which is the same or similar to the present invention, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present invention.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
The content of different metal elements at different parts of the manganese iron phosphate precursor is measured by adopting an ICP method, and the specific method comprises the following steps: 1g of the sample was digested by adding it to 20mL of hydrochloric acid solution (37 wt% hydrochloric acid: pure water=1:1), the liquid sample was pumped into the plasma torch by the atomizer, the sample was excited, the characteristic spectrum of the emitted element was reflected by a mirror, and then focused on the entrance slit of the spectrometer. When light enters the spectrometer, the light is emitted to the grating, and diffracted light irradiates the photosensitive cathode of the photomultiplier through the exit slit according to the analysis wavelength. The light corresponding to each sample is converted to electrical energy and the computer directly converts the signal intensity to the corresponding sample concentration and records the reading.
The carbon content is measured by a carbon-sulfur analyzer, specifically, a sample is oxidized by oxygen at high temperature in a combustion furnace, introduced into a carbon detection tank to measure carbon, and a reading is read on a computer.
Polyethylene glycol (weight average molecular weight 5000 g/mol).
Example 1
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
45mol of manganese nitrate, 5mol of ferric nitrate, 50mol of ammonium dihydrogen phosphate and 5mol of glucose are added, and the mol ratio of the manganese nitrate to the ferric nitrate to the ammonium dihydrogen phosphate to the glucose is 9:1:10:1; adding 12.5kg of polyethylene glycol as a dispersing agent (the mass ratio of the polyethylene glycol to the ferric nitrate is 10:1), and uniformly mixing to obtain a base solution; adding 2mol of ferrous phosphate as a complexing agent (the molar ratio of ferrous phosphate to ferric nitrate is 0.4:1), pumping 2mol/L of manganese nitrate solution, 1mol/L of ferric nitrate solution and 0.3g/L of glucose solution into a base solution according to the initial flow rate of 0.005L/s, and carrying out reaction under the atmosphere of N 2 and at the temperature of 75 ℃, wherein when the average grain size is 1.8 mu m, the flow rates of the manganese nitrate solution and the glucose solution are respectively reduced to 9/10 of the initial flow rate, and the flow rate of the ferric nitrate solution is increased to 2 times of the initial flow rate; when the average particle size is 2.5 mu m, respectively reducing the flow rate of the manganese nitrate solution and the flow rate of the glucose solution to 3/4 of the initial flow rate, improving the flow rate of the ferric nitrate solution to 3 times of the initial flow rate, and stopping the reaction when the average particle size is 3 mu m; aging, filtering, washing and drying to obtain a manganese iron phosphate precursor A1;
The molar ratio of the manganese element to the iron element at the inner core is 9:10, and the content of the carbon element is 6wt% based on the mass of the manganese iron phosphate precursor at the inner core;
the molar ratio of the manganese element to the iron element is 7.5:2.5 at the middle of the core and the surface, and the content of the carbon element is 3wt% based on the mass of the manganese iron phosphate precursor at the middle of the core and the surface;
the molar ratio of the manganese element to the iron element at the surface is 5:5, and the content of the carbon element is 2wt% based on the mass of the manganese iron phosphate precursor at the surface;
In 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A1 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 900 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material B1.
Example 2
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
45mol of manganese nitrate, 5mol of ferric nitrate, 50mol of ammonium dihydrogen phosphate and 5mol of glucose are added, and the mol ratio of the manganese nitrate to the ferric nitrate to the ammonium dihydrogen phosphate to the glucose is 9:1:10:1; adding 12.5kg of polyethylene glycol as a dispersing agent (the mass ratio of the polyethylene glycol to the ferric nitrate is 10:1), and uniformly mixing to obtain a base solution; adding 2mol of oxalic acid dihydrate as a complexing agent (the molar ratio of the oxalic acid dihydrate to the ferric nitrate is 0.4:1), pumping 2mol/L of manganese nitrate solution, 1mol/L of ferric nitrate solution and 0.3g/L of glucose solution into a base solution according to the initial flow rate of 0.005L/s, and carrying out reaction under the atmosphere of N 2 and at the temperature of 75 ℃, wherein when the average grain size is 1.8 mu m, the flow rates of the manganese nitrate solution and the glucose solution are respectively reduced to 3/4 of the initial flow rate, and the flow rate of the ferric nitrate solution is increased to 3 times of the initial flow rate; when the reaction is carried out until the average particle size is 2.5 mu m, respectively reducing the flow rate of the manganese nitrate solution and the flow rate of the glucose solution to 1/2 of the initial flow rate, and improving the flow rate of the ferric nitrate solution to 5 times of the initial flow rate until the reaction is carried out until the average particle size reaches 3 mu m; aging, filtering, washing and drying to obtain a manganese iron phosphate precursor A2;
The molar ratio of the manganese element to the iron element at the inner core is 9:10, and the content of the carbon element is 5wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 7:3 at the middle of the inner core and the surface, and the content of the carbon element is 4wt% based on the mass of the manganese iron phosphate precursor at the middle of the inner core and the surface;
the molar ratio of the manganese element to the iron element at the surface is 5:5, and the content of the carbon element is 3wt% based on the mass of the manganese iron phosphate precursor at the surface;
And in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A2 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 850 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10 hours, and cooling to obtain the lithium iron phosphate anode material B2.
Example 3
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
45mol of manganese nitrate, 5mol of ferric nitrate, 50mol of ammonium dihydrogen phosphate and 5mol of glucose are added, and the mol ratio of the manganese nitrate to the ferric nitrate to the ammonium dihydrogen phosphate to the glucose is 9:1:10:1; adding 12.5kg of polyethylene glycol as a dispersing agent (the mass ratio of the polyethylene glycol to the ferric nitrate is 10:1), uniformly mixing to obtain a base solution, adding 2mol of ferrous phosphate as a complexing agent (the mol ratio of the ferrous phosphate to the ferric nitrate is 0.4:1), pumping 2mol/L of manganese nitrate solution, 1mol/L of ferric nitrate solution and 0.3g/L of glucose solution into the base solution according to the initial flow rate of 0.05L/s, respectively, and reacting under the N 2 atmosphere and at 75 ℃, wherein when the average particle size is 1.8 mu m, the flow rates of the manganese nitrate solution and the glucose solution are respectively reduced to 2/3 of the initial flow rate, and the flow rate of the ferric nitrate solution is increased to 4 times of the initial flow rate; when the reaction is carried out until the average particle size is 2.5 mu m, respectively reducing the flow rate of the manganese nitrate solution and the flow rate of the glucose solution to 1/3 of the initial flow rate, and improving the flow rate of the ferric nitrate solution to 7 times of the initial flow rate until the average particle size reaches 3 mu m; aging, filtering, washing and drying to obtain a manganese iron phosphate precursor A3;
The molar ratio of the manganese element to the iron element at the inner core is 9:10, and the content of the carbon element is 5wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 6:4 at the middle of the inner core and the surface, and the content of the carbon element is 4wt% based on the mass of the manganese iron phosphate precursor at the middle of the inner core and the surface;
The molar ratio of the manganese element to the iron element at the surface is 3:7, and the content of the carbon element is 2wt% based on the mass of the manganese iron phosphate precursor at the surface;
And in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A3 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 800 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material B3.
Example 4
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
according to the mode of example 1, except that "the molar ratio of manganese nitrate, ferric nitrate, ammonium dihydrogen phosphate and glucose is 5:2:6:1" is used for replacing "the molar ratio of manganese nitrate, ferric nitrate, ammonium dihydrogen phosphate and glucose is 9:1:10:1", so as to obtain a manganese iron phosphate precursor A4;
The molar ratio of the manganese element to the iron element at the inner core is 8:2, and the content of the carbon element is 5wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 6:4 at the middle of the inner core and the surface, and the content of the carbon element is 3wt% based on the mass of the manganese iron phosphate precursor at the middle of the inner core and the surface;
At the surface, the molar ratio of the manganese element to the iron element is 4.8:5.2, and the content of the carbon element is 2wt% based on the mass of the manganese iron phosphate precursor at the surface;
And in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A4 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 800 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10 hours, and cooling to obtain the lithium iron phosphate anode material B4.
Example 5
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
in the same manner as in example 1 except that "the initial flow rate was 0.1L/s" was used instead of "the initial flow rate was 0.005L/s", a ferromanganese phosphate precursor A5 was obtained;
The molar ratio of the manganese element to the iron element at the inner core is 9:10, and the content of the carbon element is 8wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 7.8:2.2 at the middle of the core and the surface, and the content of the carbon element is 3.5wt% based on the mass of the manganese iron phosphate precursor at the middle of the core and the surface;
the molar ratio of the manganese element to the iron element at the surface is 5:5, and the content of the carbon element is 2wt% based on the mass of the manganese iron phosphate precursor at the surface;
And in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A5 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 800 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material B5.
Example 6
The embodiment provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
according to the manner of example 1, except that "0.2g/L of glucose solution" was used instead of "0.3g/L of glucose solution", manganese iron phosphate precursor A6 was obtained;
the molar ratio of the manganese element to the iron element at the inner core is 8.5:1.5, and the content of the carbon element is 8wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 7.5:2.5 at the middle of the core and the surface, and the content of the carbon element is 4wt% based on the mass of the manganese iron phosphate precursor at the middle of the core and the surface;
At the surface, the molar ratio of the manganese element to the iron element is 4.5:5.5, and the content of the carbon element is 2wt% based on the mass of the manganese iron phosphate precursor at the surface;
And in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor A6 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 800 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material B6.
Comparative example 1
The comparative example provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
45mol of manganese nitrate, 5mol of ferric nitrate, 50mol of ammonium dihydrogen phosphate and 5mol of glucose are added, and the mol ratio of the manganese nitrate to the ferric nitrate to the ammonium dihydrogen phosphate to the glucose is 9:1:10:1; adding 12.5kg of polyethylene glycol as a dispersing agent, and uniformly mixing to obtain a base solution; adding 2mol of ferrous phosphate as a complexing agent, pumping 2mol/L of manganese nitrate solution, 1mol/L of ferric nitrate solution and 0.3g/L of glucose solution into a base solution according to the initial flow rate of 0.005L/s, and stopping reacting until the average particle size reaches 3 mu m under the atmosphere of N 2 at 75 ℃; aging, filtering, washing and drying to obtain a manganese iron phosphate precursor DA1;
The molar ratio of the manganese element to the iron element at the inner core is 9:10, and the content of the carbon element is 6wt% based on the mass of the manganese iron phosphate precursor at the inner core;
The molar ratio of the manganese element to the iron element is 9:10 at the middle of the inner core and the surface, and the content of the carbon element is 6wt% based on the mass of the manganese iron phosphate precursor at the middle of the inner core and the surface;
The molar ratio of the manganese element to the iron element at the surface is 9:10, and the content of the carbon element is 6wt% based on the mass of the manganese iron phosphate precursor at the surface;
In 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor DA1 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 850 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material DB1.
Comparative example 2
The comparative example provides a lithium iron manganese phosphate positive electrode material, which comprises the following specific preparation steps and operation parameters:
according to the manner of example 1, except that "45 mol of manganese nitrate, 5mol of ferric nitrate, 50mol of monoammonium phosphate were added" instead of "45 mol of manganese nitrate, 5mol of ferric nitrate, 50mol of monoammonium phosphate, and 5mol of glucose were added", manganese iron phosphate precursor DA2 was obtained;
The molar ratio of the manganese element to the iron element at the inner core is 9.5:0.5, and the content of the carbon element is 0 based on the mass of the manganese iron phosphate precursor at the inner core;
the molar ratio of the manganese element to the iron element is 8.5:1.5 at the middle of the core and the surface, and the content of the carbon element is 0 based on the mass of the manganese iron phosphate precursor at the middle of the core and the surface;
the molar ratio of the manganese element to the iron element at the surface is 7:3, and the content of the carbon element is 0 based on the mass of the manganese iron phosphate precursor at the surface;
in 250g of water, uniformly mixing lithium carbonate and a manganese iron phosphate precursor DA2 according to a molar ratio of 0.5:1, performing sanding treatment, spray drying, heating to 850 ℃ at a speed of 2 ℃/min under an N 2 atmosphere, preserving heat for 10h, and cooling to obtain the lithium iron phosphate anode material DB2.
Comparative example 3
Weighing 100g of manganese sesquioxide, a tetraoxide, lithium carbonate (manganese sesquioxide, a tetraoxide and lithium carbonate according to a metal molar ratio of 6:4:10.3), weighing 2g of glucose, mixing 250g of deionized water, sanding, and spray drying to obtain a lithium iron phosphate positive electrode material precursor DA3; and in the N 2 atmosphere, heating to 800 ℃ at a speed of 2 ℃/min, preserving heat for 10 hours, and cooling to obtain the lithium iron phosphate anode material DB3.
The positive electrode materials obtained in examples and comparative examples were assembled into a battery.
And uniformly mixing the prepared anode material with acetylene black serving as a conductive agent, namely PVDF serving as a binder according to a mass ratio of 90:5:5, adding 4g of 1-methyl-2 pyrrolidone, ball milling for 1h to prepare slurry, uniformly coating the slurry on an aluminum sheet, coating the slurry on a current collector, and drying and tabletting to prepare the anode sheet. The metal lithium sheet is used as a negative electrode to assemble a 2032 button cell, a blue electric test system is used for electric performance test, the charge and discharge voltage is 2.0-4.2V, the first circle is charged and discharged at 0.1C/0.1C, and then the cycle is 200 circles at 1C/1C.
The method for testing the discharge platform voltage of the battery prepared from the lithium iron phosphate positive electrode material comprises the following steps: data are collected through voltage intervals, then the voltage curve is differentiated, and the voltage of the platform is determined through the peak value of dQ/dV.
The method for testing the manganese element leaching amount of the battery prepared from the lithium iron phosphate positive electrode material comprises the following steps: the ICP method is adopted, and the concrete method comprises the following steps: 1g of the sample was digested by adding it to 20mL of hydrochloric acid solution (37 wt% hydrochloric acid: pure water=1:1), the liquid sample was pumped into the plasma torch by the atomizer, the sample was excited, the characteristic spectrum of the emitted element was reflected by a mirror, and then focused on the entrance slit of the spectrometer. When light enters the spectrometer, the light is emitted to the grating, and diffracted light irradiates the photosensitive cathode of the photomultiplier through the exit slit according to the analysis wavelength. The light corresponding to each sample is converted to electrical energy and the computer directly converts the signal intensity to the corresponding sample concentration and records the reading.
The specific test results are shown in table 1.
TABLE 1
| Gram discharge capacity (mAh/g) | Manganese element elution amount (wt%) | Discharge platform voltage (V) | |
| Example 1 | 130.1 | 0.0032 | 3.84 |
| Example 2 | 134.3 | 0.0048 | 3.8 |
| Example 3 | 138.5 | 0.0083 | 3.65 |
| Example 4 | 142 | 0.0099 | 3.6 |
| Example 5 | 126.1 | 0.0123 | 3.87 |
| Example 6 | 136.3 | 0.0078 | 3.77 |
| Comparative example 1 | 88.9 | 0.0158 | 3.95 |
| Comparative example 2 | 117.7 | 0.0224 | 3.9 |
| Comparative example 3 | 140.3 | 0.0185 | 3.63 |
The invention provides a manganese iron phosphate precursor, wherein from an inner core to a surface, the content of manganese element is decreased, the content of iron element is increased, and the content of carbon element is decreased; the contents of the three elements show gradient distribution and synergistic effect, and the battery containing the lithium iron manganese phosphate positive electrode material prepared from the precursor can give consideration to higher discharge gram capacity and discharge platform voltage, so that the leaching amount of manganese element is reduced;
As is clear from comparison between example 1 and comparative example 2, the discharge plateau voltage of comparative example 2 still maintains a high value, but the discharge gram capacity is greatly reduced, which proves that the gradient distribution of carbon content enhances electron conductivity, promotes migration and diffusion of lithium ions, improves the conductivity of the battery, and reduces the leaching amount of manganese element.
As can be seen from comparison of example 1 and example 6, the discharge plateau voltage is reduced while the discharge gram capacity of example 6 remains high, which can prove that the specific carbon source concentration can improve the electrical performance of the cathode material, and the discharge gram capacity and the discharge plateau voltage are both high.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (10)
1. The ferromanganese phosphate precursor is characterized by comprising manganese element, iron element and carbon element; wherein, from the inner core to the surface, the content of manganese element is decreased, the content of iron element is increased, and the content of carbon element is decreased.
2. The ferromanganese phosphate precursor according to claim 1, wherein the molar ratio of manganese element to iron element at the core is (8-9): (1-2);
And/or, the content of the carbon element is 5-8wt% based on the mass of the manganese iron phosphate precursor at the inner core;
And/or the molar ratio of manganese element to iron element is (6-7.5) (2.2-4) at the middle of the inner core and the surface;
and/or the content of the carbon element is 2-4wt% based on the mass of the manganese iron phosphate precursor at the middle of the core and the surface;
And/or, at the surface, the molar ratio of the manganese element to the iron element is (3-5): 5-7;
and/or the content of the carbon element is 1-2wt% based on the mass of the manganese iron phosphate precursor at the surface.
3. The manganese iron phosphate precursor according to claim 1 or 2, wherein the manganese iron phosphate precursor has an average particle size of 3-5 μm.
4. The preparation method of the ferric manganese phosphate precursor is characterized by comprising the following steps of:
step 1, mixing a first manganese source, a first iron source, a first phosphorus source and a first carbon source to obtain a base solution;
Step 2, adding a manganese source solution, an iron source solution, a carbon source solution and a complexing agent into the base solution at an initial flow rate to perform a reaction, and respectively reducing the flow rates of the manganese source solution and the carbon source solution to 2/3-9/10 of the initial flow rates when the average particle size of the reaction reaches 1.5-2 mu m; increasing the flow rate of the iron source solution to 2-4 times of the initial flow rate;
when the reaction is carried out until the average particle size is 2.5-2.8 mu m, respectively reducing the flow rate of the manganese source solution and the flow rate of the carbon source solution to 1/3-3/4 of the initial flow rate; increasing the flow rate of the iron source solution to 3-7 times of the initial flow rate;
And step 3, ageing the material obtained after the reaction in the step 2, and separating to obtain a manganese iron phosphate precursor.
5. The method according to claim 4, wherein in step 1, the molar ratio of the first manganese source, the first iron source, the first phosphorus source, and the first carbon source is (5-10): 0.5-2): 5-12): 1, preferably (8-9): 1-1.5): 9-10): 1;
Optionally, in step 1, a dispersing agent is added before mixing;
optionally, the mass ratio of the dispersing agent to the first iron source is 8-12:1;
Optionally, the dispersant comprises polyethylene glycol and/or polyacrylamide.
6. The method of claim 4 or 5, wherein in step 2, the molar ratio of the complexing agent to the first iron source is from 0.3 to 0.6:1;
Optionally, in step 2, the complexing agent comprises ferrous phosphate and/or oxalic acid dihydrate;
Optionally, in the step 2, the manganese source solution contains a second manganese source and water, wherein the concentration of the second manganese source is 1.8-2.2mol/L;
Optionally, in the step 2, the iron source solution contains a second iron source and water, wherein the concentration of the second iron source is 0.7-1.3mol/L;
optionally, in step 2, the carbon source solution contains a second carbon source and water, wherein the concentration of the second carbon source is 0.3-0.5g/L;
optionally, the first manganese source and the second manganese source are each independently selected from at least one of manganese nitrate, manganese sulfate, and manganese carbonate;
optionally, the first iron source and the second iron source are each independently selected from at least one of ferric nitrate, manganese sulfate, and manganese carbonate;
Optionally, the first carbon source and the second carbon source are each independently selected from at least one of glucose, fructose, and ribose.
7. The method according to any one of claims 4 to 6, wherein in step 2, the initial flow rate is 0.005 to 0.1L/s;
Optionally, the reaction conditions include: the reaction temperature is 50-80 ℃.
8. A manganese iron phosphate precursor produced by the production method of any one of claims 4 to 7.
9. A lithium manganese iron phosphate positive electrode material, characterized in that the lithium manganese iron phosphate positive electrode material is prepared by sintering a lithium source and the lithium manganese iron phosphate precursor according to any one of claims 1-3 or claim 8;
optionally, the molar ratio of the lithium source to the manganese iron phosphate precursor is 0.5-1.2:1.
10. Use of the lithium iron manganese phosphate positive electrode material according to claim 9 in a lithium ion battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410210193.7A CN118083937A (en) | 2024-02-26 | 2024-02-26 | Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410210193.7A CN118083937A (en) | 2024-02-26 | 2024-02-26 | Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118083937A true CN118083937A (en) | 2024-05-28 |
Family
ID=91141636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410210193.7A Pending CN118083937A (en) | 2024-02-26 | 2024-02-26 | Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118083937A (en) |
-
2024
- 2024-02-26 CN CN202410210193.7A patent/CN118083937A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101661827B1 (en) | Positive electrode active material for lithium-ion cell, positive electrode for lithium-ion cell, and lithium-ion cell | |
| CN107331852A (en) | Nickel-cobalt-manganese ternary combination electrode material of improved oxide surface cladding and preparation method thereof | |
| CN105742629A (en) | In-situ preparation method of positive electrode material lithium iron phosphate/graphene compound for lithium-ion battery | |
| CN105720254A (en) | Preparation method for carbon-coated lithium vanadate used as negative electrode material of lithium ion battery | |
| CN110474039B (en) | Sodium-ion battery positive electrode material and preparation method and application thereof | |
| CN110970615A (en) | Modification method of high-performance lithium manganate positive electrode material | |
| CN118083937A (en) | Manganese iron phosphate precursor, manganese iron lithium phosphate positive electrode material, preparation method and application | |
| CN111540901B (en) | Method for preparing lithium iron phosphate (LEP) by using lithium iron phosphate (III) | |
| CN109638275A (en) | A kind of selenium, the nickelic positive electrode of silicate codope and its preparation method and application | |
| US11942643B2 (en) | Doped sodium vanadium phosphate and preparation method and application thereof | |
| CN116750740A (en) | Method for recycling waste lithium iron phosphate battery | |
| CN116443839A (en) | Preparation method of lithium iron manganese phosphate | |
| CN105655574B (en) | A kind of nickel lithium manganate cathode material and preparation method thereof | |
| CN114655943B (en) | Lithium iron manganese phosphate composite material, preparation method thereof, positive electrode and lithium ion battery | |
| US20240222623A1 (en) | Iron-manganese-based positive electrode material, and preparation method therefor and use thereof | |
| CN105655575A (en) | Lithium-ion battery cathode material and preparation method thereof | |
| CN110808371A (en) | Multi-element lithium-rich manganese-based positive electrode material and preparation method and application thereof | |
| CN115259128B (en) | Preparation method of high-compaction high-capacity low-cost lithium iron phosphate | |
| CN114560511B (en) | High-nickel positive electrode material with high cycle stability and preparation method thereof | |
| CN115849330B (en) | Lithium iron manganese phosphate positive electrode material and preparation method thereof | |
| CN114436234B (en) | Use of FePO 4 Lithium iron phosphate material prepared from/C composite material and preparation method thereof | |
| CN116314765A (en) | Core-shell structured lithium iron manganese phosphate material and preparation method and application thereof | |
| CN116573627A (en) | Vanadium-containing ore Na + Method for preparing lithium vanadium phosphate lithium battery anode material by in-situ doping | |
| CN116666601A (en) | Water-soluble titanium doped positive electrode material, preparation method and battery | |
| FR3143209A1 (en) | LITHIUM-MANGANESE-IRON PHOSPHATE CATHODE MATERIAL AND PREPARATION METHOD THEREFOR |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |