CN115974161A - Manganous manganic oxide pre-intercalated lithium intermediate and preparation method and application thereof - Google Patents
Manganous manganic oxide pre-intercalated lithium intermediate and preparation method and application thereof Download PDFInfo
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 183
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 183
- GEYXPJBPASPPLI-UHFFFAOYSA-N manganese(III) oxide Inorganic materials O=[Mn]O[Mn]=O GEYXPJBPASPPLI-UHFFFAOYSA-N 0.000 title claims abstract description 31
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims abstract description 80
- 239000000463 material Substances 0.000 claims abstract description 67
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000001301 oxygen Substances 0.000 claims abstract description 56
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 56
- 238000006243 chemical reaction Methods 0.000 claims abstract description 52
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 43
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 36
- 238000000034 method Methods 0.000 claims abstract description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 230000008569 process Effects 0.000 claims abstract description 20
- 229910002102 lithium manganese oxide Inorganic materials 0.000 claims abstract description 14
- VLXXBCXTUVRROQ-UHFFFAOYSA-N lithium;oxido-oxo-(oxomanganiooxy)manganese Chemical compound [Li+].[O-][Mn](=O)O[Mn]=O VLXXBCXTUVRROQ-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000010406 cathode material Substances 0.000 claims abstract description 8
- 239000013078 crystal Substances 0.000 claims abstract description 8
- 229910052596 spinel Inorganic materials 0.000 claims abstract description 8
- 239000011029 spinel Substances 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims abstract description 8
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 claims description 105
- 238000009830 intercalation Methods 0.000 claims description 76
- 230000002687 intercalation Effects 0.000 claims description 76
- 239000002245 particle Substances 0.000 claims description 61
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical group [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 48
- 239000011572 manganese Substances 0.000 claims description 35
- 229910052748 manganese Inorganic materials 0.000 claims description 22
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 7
- 238000001354 calcination Methods 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 5
- 230000035484 reaction time Effects 0.000 claims description 4
- 238000010304 firing Methods 0.000 claims description 2
- 238000005265 energy consumption Methods 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 4
- 239000000543 intermediate Substances 0.000 description 105
- 239000000047 product Substances 0.000 description 44
- 239000012071 phase Substances 0.000 description 33
- 239000002994 raw material Substances 0.000 description 27
- 239000013067 intermediate product Substances 0.000 description 24
- 238000001514 detection method Methods 0.000 description 22
- 238000009826 distribution Methods 0.000 description 19
- 239000002243 precursor Substances 0.000 description 18
- VASIZKWUTCETSD-UHFFFAOYSA-N manganese(II) oxide Inorganic materials [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 17
- 239000007774 positive electrode material Substances 0.000 description 15
- 238000002441 X-ray diffraction Methods 0.000 description 13
- 238000010532 solid phase synthesis reaction Methods 0.000 description 13
- 238000001878 scanning electron micrograph Methods 0.000 description 12
- 238000001816 cooling Methods 0.000 description 11
- 239000000203 mixture Substances 0.000 description 10
- 229910001416 lithium ion Inorganic materials 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 8
- 230000014759 maintenance of location Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000007873 sieving Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000007599 discharging Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 238000000967 suction filtration Methods 0.000 description 6
- 238000003786 synthesis reaction Methods 0.000 description 6
- KLARSDUHONHPRF-UHFFFAOYSA-N [Li].[Mn] Chemical compound [Li].[Mn] KLARSDUHONHPRF-UHFFFAOYSA-N 0.000 description 5
- 238000005054 agglomeration Methods 0.000 description 5
- 230000002776 aggregation Effects 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 239000007795 chemical reaction product Substances 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000012798 spherical particle Substances 0.000 description 4
- 239000010405 anode material Substances 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000012065 filter cake Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 3
- 229910052808 lithium carbonate Inorganic materials 0.000 description 3
- PPNAOCWZXJOHFK-UHFFFAOYSA-N manganese(2+);oxygen(2-) Chemical compound [O-2].[Mn+2] PPNAOCWZXJOHFK-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 238000007665 sagging Methods 0.000 description 3
- 238000003892 spreading Methods 0.000 description 3
- 230000007480 spreading Effects 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 239000010431 corundum Substances 0.000 description 2
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910002982 Li2MnO3 phase Inorganic materials 0.000 description 1
- WAEMQWOKJMHJLA-UHFFFAOYSA-N Manganese(2+) Chemical group [Mn+2] WAEMQWOKJMHJLA-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 229940010514 ammonium ferrous sulfate Drugs 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 239000012792 core layer Substances 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- PQVSTLUFSYVLTO-UHFFFAOYSA-N ethyl n-ethoxycarbonylcarbamate Chemical compound CCOC(=O)NC(=O)OCC PQVSTLUFSYVLTO-UHFFFAOYSA-N 0.000 description 1
- IMBKASBLAKCLEM-UHFFFAOYSA-L ferrous ammonium sulfate (anhydrous) Chemical compound [NH4+].[NH4+].[Fe+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O IMBKASBLAKCLEM-UHFFFAOYSA-L 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- GLXDVVHUTZTUQK-UHFFFAOYSA-M lithium hydroxide monohydrate Substances [Li+].O.[OH-] GLXDVVHUTZTUQK-UHFFFAOYSA-M 0.000 description 1
- 229940040692 lithium hydroxide monohydrate Drugs 0.000 description 1
- QEXMICRJPVUPSN-UHFFFAOYSA-N lithium manganese(2+) oxygen(2-) Chemical class [O-2].[Mn+2].[Li+] QEXMICRJPVUPSN-UHFFFAOYSA-N 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 150000002696 manganese Chemical class 0.000 description 1
- 229910001437 manganese ion Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000004382 potting Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G45/00—Compounds of manganese
- C01G45/02—Oxides; Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G45/00—Compounds of manganese
- C01G45/12—Manganates manganites or permanganates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
-
- 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
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a manganous manganic oxide pre-intercalated lithium intermediate, which comprises a manganous manganic oxide phase and a pre-intercalated lithium element, wherein the lithium element is coated or intercalated into the manganous manganic oxide phase by the lithium manganese oxide phase, and the molar ratio of the pre-intercalated lithium element to the manganese element is consistent with the stoichiometric ratio of the lithium element to the manganese element in a target lithium manganate material prepared based on the pre-intercalated lithium intermediate. During preparation, manganous manganic oxide, a lithium source and water are put into a pressure reaction kettle, the temperature in the kettle is controlled to be more than 100 ℃ under the condition of introducing oxygen, the internal pressure of the kettle is controlled to be more than 0.1MPa, and the reaction is fully and completely carried out under the stirring condition to obtain a pre-intercalated lithium intermediate. And (3) roasting the dry material or the wet material of the pre-intercalated lithium intermediate in an aerobic atmosphere, completely roasting and completing the crystal structure conversion to obtain the spinel type lithium manganate cathode material. The invention has the advantages of short process flow, low energy consumption, good product uniformity and the like.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery anode materials, and particularly relates to a lithium manganate anode material precursor, a preparation method and application thereof.
Background
The lithium manganate used as the positive electrode material of the lithium ion battery and synthesized by using the trimanganese tetroxide as the precursor has the characteristics of high capacity, good cycle and high-temperature performance, low magnetic foreign matter, good safety performance and the like, and is an ideal raw material for manufacturing the low-cost power and energy storage lithium ion battery.
At present, the process route for synthesizing lithium manganate by using trimanganese tetroxide as a precursor is the same as that of a ternary cathode material, and a high-temperature solid phase method is adopted, namely, trimanganese tetroxide and lithium carbonate or lithium hydroxide are fully and mechanically mixed, then the mixture is put into a sagger, the mixture is placed in a continuous kiln at 700-850 ℃ in the air for primary roasting for 10-15 hours, and after cooling and crushing, the mixture is roasted for about 10 hours for the second time, and after cooling, the product is prepared by the working procedures of crushing, iron removal, sieving and the like.
The high-temperature solid phase method for synthesizing the cathode material has the advantages that: the product inherits the advantages of low impurity content, regular and controllable appearance and the like of the precursor on the physical and chemical indexes, gives consideration to the balance of high gram capacity and good cycle performance on the electrical performance index, and is favorable for improving the energy density of the battery due to high compaction density.
The high-temperature solid-phase method for synthesizing lithium manganate by using manganous manganic oxide has the more prominent defects: firstly, the requirement on the uniform mixing effect is high. The manganous manganic oxide powder and the lithium carbonate or lithium hydroxide powder are mechanically mixed, and due to the difference of powder materials in the aspects of input amount, particle size, specific surface area, loose loading, tap density and the like, the micro uniform mixing effect is difficult to achieve, and the problem of local lithium enrichment/lithium depletion is easy to occur. Secondly, the process flow is long. And after the first roasting is finished, carrying out second roasting, wherein the operations of cooling, crushing, sieving, re-potting, feeding and the like are required in the second roasting. Thirdly, the energy consumption is high. On one hand, the heat preservation roasting temperature is higher than the melting temperature of lithium carbonate or lithium hydroxide, a slow temperature rise program is needed in the process, the problems of agglomeration and lithium intercalation unevenness caused by microcosmic sagging of a lithium source are avoided, and on the other hand, enough time is needed after the heat preservation temperature is reached to allow lithium ions and oxygen in the ambient atmosphere to migrate into the micro powder particles, so that a uniform and stable crystal structure is formed. Fourthly, the quality stability is poor. Due to the macroscopic and microscopic differences of the uniform mixing effect, the temperature rise control, the heat preservation temperature, the time and other factors, the performance of the product of the same sagger is obviously different between the upper layer and the lower layer of the sagger and between the edge and the middle of the sagger.
At present, there are many reports on hydrothermal synthesis of lithium manganate, and the method mainly comprises mixing soluble manganese salt, soluble lithium source and soluble oxidant, placing the mixture in a pressure reactor, carrying out high-temperature pressurized reaction at a temperature of more than 100 ℃ to obtain nano-scale or submicron-scale precipitate, and carrying out post-treatment such as separation and drying to obtain the product. Although the obtained product has characteristics in performance indexes such as capacity, circulation and the like, the indexes such as particle size, morphology, specific surface area and the like are uncontrollable, and most of the product is mixed with anion or cation impurities brought by reaction raw materials, so that the quality and the electrical property of the product are influenced, and no practical application is formed.
Disclosure of Invention
The invention aims to solve the technical problems that the defects and defects (such as long process flow, high energy consumption, high product uniformity control difficulty and the like) mentioned in the background technology are overcome, and a manganous manganic oxide pre-intercalated lithium intermediate and a preparation method thereof are provided.
In order to solve the technical problems, the technical scheme provided by the invention is a manganous manganic oxide pre-lithium intercalation intermediate, the pre-lithium intercalation intermediate comprises a manganous manganic oxide phase and a pre-intercalated lithium element, the lithium element is coated or intercalated into the manganous manganic oxide phase by the lithium manganese oxide phase, and the molar ratio of the pre-intercalated lithium element in the pre-lithium intercalation intermediate to the manganese element in the pre-intercalated lithium intermediate is consistent with the stoichiometric ratio of the lithium element to the manganese element in a target lithium manganate material prepared based on the pre-lithium intercalation intermediate. The pre-intercalated lithium intermediate provided by the invention can realize structural transformation through one-time roasting, and the spinel type lithium manganate cathode material with a stable structure is obtained.
The manganous manganic oxide pre-lithium intercalation intermediate can be one or more, and after differential thermal scanning is carried out on a sample of the pre-lithium intercalation intermediate in a nitrogen environment, the weight loss is found to be less than 2% before 420 ℃, which indicates that the structural water content is low; the difference thermal scanning is carried out in an oxygen environment, the mass is increased by about 2 percent between 250 ℃ and 613 ℃, which indicates that the intermediate has the oxygen absorption process, and this also indicates that oxygen is introduced in the synthesis process of the pre-intercalated lithium intermediate, so that the valence state of manganese in the lithium manganese oxide phase is higher than the average valence state of manganese in trimanganese tetroxide. More preferably, the lithium manganese oxide contains mainly Li 2 MnO 3 。
Although the phase of the manganomanganic oxide pre-intercalated lithium intermediate can be basically determined, considering the complexity of the generation of the lithium manganese oxide under different process conditions and the possible difference of different XRD pattern peak positions, the pre-intercalated lithium intermediate has the XRD diffraction pattern meeting the following conditions which can be considered to meet the preferable requirements of the invention: 2 θ has a diffraction peak at 18.5 ° ± 0.5 ° with an intensity greater than 600 cps; 2 theta has a diffraction peak with an intensity of more than 200cps (preferably more than 400 cps) at 44.5 DEG + -0.5 DEG, and 2 theta has at least three (preferably 3-4) diffraction peaks with an intensity in the range of 80-260cps in the range of 58-66 deg.
Preferably, the pre-lithium intercalation intermediate is prepared by performing hydrothermal reaction on manganous-manganic oxide and a lithium source under the condition of introducing oxygen. The preferable scheme is that firstly, under the condition of oxygen introduction, hydrothermal reaction of manganous manganic oxide and a lithium source (such as lithium hydroxide) is carried out to obtain a pre-lithium intercalation intermediate, and then the pre-lithium intercalation intermediate is roasted to realize structural transformation, so that the spinel type lithium manganate cathode material with stable structure is obtained.
As a general technical concept, the present invention also provides a method for preparing a trimanganese tetroxide pre-lithium intercalation intermediate, comprising the steps of:
putting manganous-manganic oxide, a lithium source and water into a pressure reaction kettle, controlling the temperature in the kettle to be more than 100 ℃ and the internal pressure of the kettle to be more than 0.1MPa under the condition of introducing oxygen (not limited to pure oxygen), and fully and completely reacting under the stirring condition to obtain a pre-intercalated lithium intermediate;
the input amount of the lithium source is determined according to the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared by the pre-lithium intercalation intermediate.
According to the preparation method, lithium intercalation is carried out on the trimanganese tetroxide through a hydrothermal reaction, and oxygen introduction (such as continuous oxygen introduction) is used as a necessary condition, so that manganese elements in the trimanganese tetroxide are oxidized into a higher valence state, and then lithium intercalation is realized. Through the hydrothermal reaction of the invention, almost all the manganous-manganic oxide micro particles can realize the pre-intercalation of lithium ions, and the phenomenon of non-uniform intercalation of lithium easily occurring in the solid-phase synthesis is thoroughly solved.
In the above preparation method, preferably, the lithium source is lithium hydroxide. The lithium hydroxide is selected because of strong alkalinity, which is beneficial to promoting the oxidation of the trimanganese tetroxide, and other new impurities or new gas products are not introduced, thereby avoiding the change of reaction atmosphere or the uncontrollable reaction pressure. More preferably, the lithium hydroxide is selected from particles with a particle size of less than 10mm (more preferably less than 5 mm). The input amount of the lithium hydroxide raw material is basically determined according to the stoichiometric ratio of a target lithium manganate material, and particularly the input amount of the lithium hydroxide can be basically determined according to the mass of the manganous manganic oxide input into a pressure reaction kettle and the lithium manganese ratio in the target lithium manganate. Because the invention adopts a wet hydrothermal reaction, the lithium hydroxide does not need to use micro powder with very fine granularity, and the particle material with the particle size of less than 10mm can achieve the effect of lithium pre-embedding, and simultaneously reduces the operation steps of ball milling, crushing and the like and the energy consumption.
In the above preparation method, preferably, the mass ratio of the manganous-manganic oxide to the water is controlled to be 1: 0.3-10. The concentration of the reaction system of the preparation method is controlled by the mass ratio of the trimanganese tetroxide to the water, if the reaction system is too thick, the stirring is not facilitated, and if the reaction system is too thin, the reaction system needs higher reaction temperature and longer reaction time, and repeated experiments show that the effect achieved by the preferable mass ratio range is better.
In the preparation method, the temperature in the kettle is preferably controlled to be 110-250 ℃, and the reaction time is preferably controlled to be 4-12 hours. Preferably, a certain temperature value within the temperature range is selected for carrying out the isothermal reaction, generally, the higher the temperature is selected, the shorter the time required for the reaction is; however, our experiments show that if the temperature is too high, the reaction is too fast, and the floccule phenomenon appears on the surface layer of the particles, which affects the final pre-lithium intercalation effect. Although the control is preferably constant temperature in production, the fluctuation of the temperature value within a certain range is allowed, and the fluctuation range is mainly determined by the regulation and control precision of the temperature control equipment.
In the above preparation method, preferably, the gauge pressure in the autoclave is controlled to be 0.2 to 5.0MPa, and the pressure in the autoclave after the introduction of oxygen exceeds the saturated vapor pressure of water vapor at the corresponding temperature in the autoclave. The reaction temperature in the pre-lithium embedding kettle controlled by the invention exceeds 100 ℃, and the pressure in the pressure reaction kettle exists under the consideration of the vapor pressure of water, so the pressure in the kettle exceeds the saturated vapor pressure of the vapor at the corresponding temperature in the kettle after oxygen is preferably introduced, otherwise, the oxygen introduction effect is difficult to guarantee. As for the degree that the pressure in the kettle is higher than the saturated vapor pressure of water vapor at the reaction temperature after oxygen introduction, no special requirement is made so as to ensure that oxygen can smoothly enter the kettle, but an over-high pressure atmosphere is not required to be maintained so as to avoid safety risks.
In the above production method, preferably, the introduction of oxygen into the pressure reactor is performed continuously, and oxygen is introduced from the start of temperature rise of the reaction material, and before the introduction of oxygen, an operation of discharging air is performed in the pressure reactor. Our experiments show that after the charging is completed and before the temperature is raised to the target reaction temperature, air is preferably exhausted, otherwise, the air at the upper part in the pressure reaction kettle generates larger pressure along with the rise of the temperature in the reaction kettle, and the regulation and control of the oxygen introducing pressure are influenced. The air exhaust operation can be performed by first vacuumizing and then introducing oxygen, and preferably, the air is exhausted by continuously introducing oxygen. The continuous oxygen introduction can be realized by regulating a pressure stabilizing valve of oxygen, and during operation, the pressure in the pressure reaction kettle is higher than the saturated vapor pressure of water vapor at the reaction temperature until the reaction time is finished.
In order to obtain better cycle performance, excessive lithium is usually added to replace part of manganese ion positions with lithium ions to form non-stoichiometric lithium manganate with a chemical formula expressed as Li 1+x Mn 2 O 4 . Under the condition of controlling the lithium manganese ratio of the target lithium manganate product, the reaction which occurs on the single intermediate particles may comprise:
of these, the lithium pre-intercalated lithium manganese oxides are preferably predominantly of the formula Li 2 MnO 3 The oxide form of (a) is consistent with the later XRD pattern detection data, and the intermediate particles are Li probably 2 MnO 3 Coated Mn 3 O 4 . Our XRD patterns of the pre-intercalated lithium intermediate showed (see the detailed description) that it is predominantly composed of Mn 3 O 4 With Li phase 2 MnO 3 Phase composition. In addition, based on the subsequent electron microscope image, the surface layer of the pre-lithium intercalation intermediate is fine crystal particles, the XRD pattern of the pre-lithium intercalation intermediate has the characteristic of a lithium-rich manganese phase, and the pre-lithium intercalation intermediate is considered to be Mn possibly 3 O 4 With lithium-rich manganese (Li being particularly preferred) 2 MnO 3 ) And is preferably Li 2 MnO 3 Coated with manganous-manganic oxide.
As a general technical concept, the invention further provides an application of the manganous manganic oxide pre-lithium intercalation intermediate, wherein a dry material or a wet material of the pre-lithium intercalation intermediate is roasted in an oxygen atmosphere (the oxygen atmosphere can be air, oxygen or a mixture of air and oxygen), and after the roasting is completed and the crystal structure conversion is completed, the spinel type lithium manganate positive electrode material is obtained.
In the whole technical route, firstly, the pre-lithium intercalation intermediate slurry is generated by reaction in a pressure reaction kettle, and then the slurry is subjected to solid-liquid separation (the solid-liquid separation mode can be suction filtration, filter pressing or centrifugal separation), so that the pre-lithium intercalation intermediate is obtained. Our experiments show that the spinel type lithium manganate product with an intact crystal structure can be prepared by drying the pre-intercalated lithium intermediate and then roasting, or directly roasting the wet material of the pre-intercalated lithium intermediate.
Whether dry or wet using a pre-intercalated lithium intermediate, the reaction is as follows:
in the roasting process, oxygen is supplemented from the ambient atmosphere to carry out phase change to obtain the spinel type lithium manganate with stable structure. Since partial oxidation of manganese has already been completed in the pre-intercalated lithium intermediate, less oxygen needs to be taken up from the ambient atmosphere than in the solid-phase synthesis, and thus the conditions for the calcination process can be further simplified.
In the above application, preferably, the wet material of the pre-lithium intercalation intermediate is selected for roasting, and the moisture content of the wet material is below 30%. Generally speaking, the moisture content of the wet material is related to material characteristics (including granularity, specific surface area, particle compactness and the like) and a separation mode, but considering the characteristics of the process route of the invention, the roasting can be realized by properly controlling the moisture content and adopting simple suction filtration, filter pressing or centrifugal separation operation to control the moisture content to be below 30%, the wet material with the moisture content of 30% is difficult to directly roast in the existing process route because the quality of a lithium manganate product is seriously influenced, but under the specific process route of the invention, the moisture can be evaporated in the temperature rise stage of roasting synthesis, and the direct roasting of the wet material can not have negative influence on the lithium manganate product based on the characteristics of a pre-embedded lithium intermediate, and compared with two-step operation of roasting after drying, the operation can be simplified and the energy consumption can be saved.
In the above application, preferably, the roasting temperature is 700-850 ℃, and the roasting time is 3-10 hours. Because lithium ions are pre-embedded in the intermediate, compared with the conventional solid phase method, the invention has the advantage that the roasting time can be shortened by more than half.
The above application, preferably, is carried out by rapidly increasing the temperature to the firing temperature range at a temperature increase rate of more than 5 ℃/min. Because lithium ions are pre-embedded in the microscopic particles, the problem of sagging of a lithium source easily generated during solid phase synthesis is solved, so the process route of the invention can omit the process of slow temperature rise and can be accepted at a faster temperature rise rate. In industrial production, the temperature rise rate of the solid phase method roasting control is 3-5 ℃/min, but the temperature rise rate of the method of the invention can not be limited by the temperature rise rate, and the temperature rise rate can be preferably more than 10 ℃/min under the permission of production equipment.
Compared with the prior art, the invention has the beneficial effects that:
1) The lithium manganate anode material prepared by adopting the manganous manganic oxide pre-intercalated lithium intermediate has very sharp diffraction peaks and high signal-to-noise ratio, shows good crystallinity and no impurity phase and is of a pure-phase spinel crystal structure.
2) The lithium manganate positive electrode material prepared by the manganous manganic oxide pre-lithium intercalation intermediate has microscopic particles, keeps the appearance of a precursor, also keeps the distribution characteristic of the precursor in particle size distribution, realizes uniform lithium intercalation of material particles, avoids the problems of local lithium enrichment/poor lithium and agglomeration in the conventional solid phase synthesis, ensures the consistency of product quality, and improves the gram capacity and cycle performance of the product.
3) According to the invention, the lithium ions are embedded into the pre-embedded lithium intermediate, so that the agglomeration phenomenon caused by the sagging of lithium source substances is avoided, and after the roasting is finished, the material is uniform in color, fluffy and fragile, does not need to be crushed, and is suitable for being directly sieved.
In conclusion, the positive electrode material product prepared by the method disclosed by the invention keeps the appearance and granularity characteristics of a precursor, realizes uniform lithium intercalation of material particles, avoids the problems of local lithium enrichment/lithium depletion and agglomeration in solid-phase synthesis, ensures the quality consistency and improves the gram capacity and cycle performance of the product. Meanwhile, compared with the solid phase synthesis process, the method simplifies the mixing and secondary roasting processes, shortens the high-temperature roasting time, reduces the energy consumption and improves the capacity of roasting equipment.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the embodiments or technical solutions in the prior art are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a comparative XRD pattern of a manganomanganic oxide raw material, a pre-intercalated lithium intermediate and a lithium manganate product in example 1 of the present invention.
FIG. 2 is an SEM image of the micro-morphology of a manganomanganic oxide raw material in example 1 of the invention.
FIG. 3 is a SEM image of the microstructure of a pre-intercalated lithium intermediate in example 1 of the invention.
FIG. 4 is a SEM image of the microstructure of the lithium manganate product of example 1 of the present invention.
FIG. 5 is a TG-DSC of a pre-intercalated lithium intermediate of example 2 of the present invention in nitrogen.
FIG. 6 is a TG-DSC of a pre-lithium intercalation intermediate of example 2 of the present invention in oxygen.
FIG. 7 is a particle size distribution diagram of a trimanganese tetroxide raw material in example 3 of the present invention.
FIG. 8 is a graph showing the particle size distribution of the pre-intercalated lithium intermediate in example 3 of the present invention.
FIG. 9 is a graph showing the particle size distribution of the lithium manganate product of example 3 of the present invention.
FIG. 10 is an XRD pattern of a pre-intercalated lithium intermediate as in example 1 of the present invention.
FIG. 11 is an XRD pattern of a pre-intercalated lithium intermediate in example 2 of the present invention.
FIG. 12 is an XRD pattern of a pre-intercalated lithium intermediate in example 3 of the present invention.
FIG. 13 is an XRD pattern of a pre-intercalated lithium intermediate in example 4 of the present invention.
Fig. 14 is a SEM image of a precursor trimanganese tetroxide material particle in example 2 of the present invention.
FIG. 15 is a SEM image of the microstructure of a pre-intercalated lithium intermediate in example 2 of the invention.
FIG. 16 is a SEM photograph of a particle cut of a pre-intercalated lithium intermediate material in example 2 of the present invention.
FIG. 17 is a SEM image of a particle cut of a lithium manganate product according to example 2 of the present invention.
FIG. 18 is a SEM image of a cut of lithium manganate product particles prepared by a conventional solid phase method.
Figure 19 is a comparative XRD pattern of pre-intercalated lithium intermediates of various embodiments of the invention.
Detailed Description
In order to facilitate an understanding of the invention, reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings, and the scope of the invention is not limited to the following specific embodiments.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In the following examples: the content of the lithium element is detected by adopting an ICP-AES method, and the content of the manganese element is detected by adopting an ammonium ferrous sulfate titration method (see GB/T21836-2008 appendix A).
In the following embodiments, the method for detecting the charging performance may be: according to the lithium manganate: PVDF: graphite: acetylene black =9, 0.2, and a metal lithium sheet is used as a negative electrode to manufacture a CR2016 button cell, and an electrical property test is performed in a temperature environment of 25 ℃ and a charging and discharging interval of 3.0V to 4.3V, and first 0.2C detection is performed, and then 1C (setting lithium manganate material 1c = 120ma/g) circulation is performed.
Example 1:
the invention relates to a preparation method of a manganous manganic oxide pre-lithium intercalation intermediate, which comprises the following steps:
adding 1000g of spherical trimanganese tetroxide with the manganese content of 69.2 percent and the granularity D50 of 11.4 mu m, 310g of lithium hydroxide (lithium hydroxide monohydrate) with the particle size of less than 1mm and the content of 56.5 percent and 5L of pure water into a nickel-lined pressure reaction kettle with the volume of 10L according to the proportion of the trimanganese tetroxide to the solid-liquid mass ratio of 1:5 of water, introducing high-pressure oxygen, continuously introducing the oxygen into the pressure reaction kettle, introducing the oxygen when the temperature of reaction materials begins to rise, and performing air exhaust operation in the pressure reaction kettle before introducing the oxygen; stirring and reacting for 5 hours at the temperature of 210 ℃ in the kettle and the gauge pressure of 2.5MPa in the kettle, cooling to below 80 ℃, removing a reaction product, and performing suction filtration to obtain a pre-intercalated lithium intermediate.
Through detection, the moisture content of the pre-lithium intercalation intermediate wet material is 21%, the granularity D50 is 11.6 mu m, the filter cake is dried for 24 hours at 120 ℃, and the lithium content and the manganese content of the dried material are 4.46% and 61.5%.
And (3) spreading 300g of the prepared pre-lithium intercalation intermediate dry material (or wet material) in a corundum sagger, placing in an air atmosphere furnace, heating to 750 ℃ at a heating rate of more than 5 ℃/min, keeping the temperature for 5 hours, then discharging after power failure and cooling to below 100 ℃, and sieving the material with a 120-mesh sieve to obtain 304g (240 g if the wet material is selected) of the lithium manganate positive electrode material. Through detection, the particle size D50 of the lithium manganate positive electrode material is 12.1 μm, the lithium content is 4.35%, the manganese content is 60.1%, and the lithium-manganese molar ratio is 0.57.
Comparison of the present example by XRD PatternXRD patterns of the medium manganic manganous oxide raw material, the prepared pre-lithium intercalation intermediate product and the finally prepared lithium manganate product are shown in figures 1 and 10. XRD of the lithium manganate product of FIG. 1 shows that the product is pure lithium manganate without impurity phase, and XRD of FIG. 10 shows that the pre-intercalated lithium intermediate product is made of Mn 3 O 4 With Li phase 2 MnO 3 Phase composition.
By comparing the particle size distribution diagrams, it was found that the particle size distributions of the pre-intercalated lithium intermediate product (having a particle size D50 of 11.6 μm) and the manganous oxide raw material (having a particle size D50 of 11.4 μm) were substantially uniform, and the particle size distribution of the pre-intercalated lithium intermediate product and the manganous oxide raw material, having a particle size D50 of 12.1 μm, was substantially followed by the lithium manganate positive electrode material finally prepared.
Comparing the trimanganese tetroxide raw material, the prepared pre-lithium intercalation intermediate product and the finally prepared lithium manganate product in the embodiment by SEM images of microscopic appearances, as shown in figures 2 to 4, the trimanganese tetroxide raw material, the pre-lithium intercalation intermediate product and the finally prepared lithium manganate product are all regular spherical particles, the microscopic appearances are good, and the uniformity and the consistency of the product are good.
Based on the above detection and analysis, we believe that the above example produces a manganomanganic pre-intercalated lithium intermediate comprising a manganomanganic oxide phase and a pre-intercalated lithium element that is lithium manganese oxide (Li) 2 MnO 3 ) The phase is coated or inserted into a manganomanganic oxide phase, and the molar ratio of the pre-inserted lithium element in the pre-inserted lithium intermediate to the manganese element therein is consistent with the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared based on the pre-inserted lithium intermediate (0.57. By comparing the precursor trimanganese tetroxide, the pre-lithium intercalation intermediate and the synthesized lithium manganate material, the fact that oxygen is introduced during the synthesis of the pre-lithium intercalation intermediate can be shown to oxidize manganese elements.
Table 1: in this example, the ratio of the components of the precursor, the intermediate and the lithium manganate is changed
In this example, the chemical formula of the lithium manganate product finally prepared is Li 1.14 Mn 2 O 4 。
And (3) carrying out electricity-buckling detection on the lithium manganate obtained by the preparation:
the detection results are as follows:
the capacity of 0.2C g is 113mAh/g, the capacity of 1C is 112mAh/g, the capacity retention rate is 95 percent after 50 times of circulation at 25 ℃, the capacity retention rate is 92 percent after 100 times of circulation.
Example 2:
the invention relates to a preparation method of a manganous-manganic oxide pre-lithium intercalation intermediate, which comprises the following steps of:
adding 3000g of spherical trimanganese tetroxide with the manganese content of 69.8 percent and the granularity D50 of 8.1 mu m, 899g of lithium hydroxide with the particle size of less than 1mm and the content of 56.5 percent and 6L of pure water into a nickel-lined pressure reaction kettle with the volume of 10L according to the proportion of the trimanganese tetroxide to the solid-liquid mass ratio of 1:2 of water, introducing high-pressure oxygen into the pressure reaction kettle continuously, introducing oxygen when the temperature of reaction materials begins to rise, and exhausting air in the pressure reaction kettle before introducing oxygen; stirring and reacting for 10 hours at the temperature of 160 ℃ in the kettle and the gauge pressure of 0.6MPa in the kettle, cooling to below 80 ℃, removing reaction products, and performing suction filtration to obtain the wet material of the pre-intercalated lithium intermediate.
Through detection, the moisture content of the pre-lithium intercalation intermediate wet material is 20.5%, the granularity D50 is 9.4 mu m, and the lithium content and the manganese content of the dried material are 4.49% and 60.9%.
And (2) spreading 300g of the prepared pre-lithium intercalation intermediate dry material (or wet material) in a corundum sagger, placing in an air atmosphere furnace, heating to 790 ℃ at a heating rate of more than 5 ℃/min, preserving heat for 5 hours, then discharging after power failure and cooling to below 100 ℃, and sieving the material with a 120-mesh sieve to obtain 307g (244 g when the wet material is selected) of the lithium manganate positive electrode material. Through detection, the particle size D50 of the lithium manganate positive electrode material is 9.5 μm, the lithium content is 4.40%, the manganese content is 59.6%, and the lithium-manganese molar ratio is 0.58.
FIG. 11 is an XRD pattern of the pre-intercalated lithium intermediate of this example, showing that the pre-intercalated lithium intermediate product is made from Mn 3 O 4 With Li phase 2 MnO 3 Phase composition.
By comparing the trimanganese tetroxide raw material, the prepared pre-intercalated lithium intermediate product and the finally prepared lithium manganate product in the present example by the particle size distribution diagram, it was found that the particle size distribution of the pre-intercalated lithium intermediate product (the particle size D50 of which is 9.4 μm) and the trimanganese tetroxide raw material (the particle size D50 of which is 8.1 μm) were substantially uniform, and the finally prepared lithium manganate positive electrode material also substantially followed the particle size distribution of the pre-intercalated lithium intermediate product and the trimanganese tetroxide raw material, the particle size D50 of which was 9.5 μm.
And comparing the trimanganese tetroxide raw material, the prepared pre-lithium intercalation intermediate product and the finally prepared lithium manganate product in the embodiment by using an SEM image of the micro-morphology, wherein the trimanganese tetroxide raw material, the pre-lithium intercalation intermediate product and the finally prepared lithium manganate product are all regular spherical particles, the micro-morphology is good, and the uniformity and the consistency of the product are good.
Based on the above detection and analysis, we found that the weight loss of the pre-intercalated lithium intermediate sample of this example is less than 2% before 420 ℃ after differential thermal scanning in a nitrogen environment, which indicates that the structural water content is low (see fig. 5); and the mass is increased by about 2 percent (see figure 6) when the lithium pre-intercalated intermediate is subjected to differential thermal scanning in an oxygen environment at the temperature of between 250 and 613 ℃, which shows that although oxygen is introduced during the synthesis process of the lithium pre-intercalated intermediate, the oxygen element is not in place in a sufficient amount and needs to be supplemented during the subsequent crystal structure conversion process.
It is believed that the above examples produce a manganomanganic pre-intercalated lithium intermediate comprising a manganomanganic oxide phase and a pre-intercalated lithium element which is lithium manganese oxide (Li) 2 MnO 3 ) Coated or embedded in a trimanganese tetroxide phaseThe molar ratio of the pre-intercalated lithium element in the pre-intercalated lithium intermediate to the manganese element therein is consistent with the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared based on the pre-intercalated lithium intermediate (0.58, see table 2 below specifically.
In addition, by comparing the cross-sectional electron micrographs of the trimanganese tetroxide pre-lithium intercalation intermediate prepared in this example and trimanganese tetroxide (see fig. 14-16), we found that the outer layer of the pre-lithium intercalation intermediate clearly generated a crystalline material (i.e., lithium manganese oxide phase) different from the inner core layer, which was substantially identical to the trimanganese tetroxide phase, further confirming the formation of the pre-lithium intercalation intermediate cladding structure of this example.
In this example, the chemical formula of the lithium manganate product finally prepared is Li 1.16 Mn 2 O 4 . The oxidation degree of the manganese element can also be roughly judged by comparing the precursor trimanganese tetroxide, the pre-intercalated lithium intermediate and the synthesized lithium manganate material. In addition, as can be seen from comparison of the cutting SEM images of the lithium manganate material shown in fig. 17 and 18, the microscopic particles of the lithium manganate positive electrode material prepared from the trimanganese tetroxide pre-intercalation intermediate maintain the morphology of the precursor, and the distribution characteristics of the precursor in particle size distribution, so that uniform intercalation of material particles is achieved, the problems of local lithium enrichment/lithium depletion and agglomeration during synthesis by the conventional solid phase method are avoided, and after calcination is completed, the material is uniform in color, fluffy and fragile, does not need to be crushed, is suitable for direct sieving treatment, has abundant active pores, and is more favorable for improving electrochemical performance.
Table 2: in this example, the ratio of the precursor to the intermediate to the lithium manganate was varied
And (3) carrying out electricity deduction detection on the lithium manganate obtained by the preparation:
the detection results are as follows:
the capacity of 0.2C g is 110mAh/g, the capacity of 1C is 109mAh/g, the capacity retention rate is 98 percent after 50 times of circulation at 25 ℃, and the capacity retention rate is 97 percent after 100 times.
Example 3:
the invention relates to a preparation method of a manganous manganic oxide pre-lithium intercalation intermediate, which comprises the following steps:
adding 1000g of spherical manganous-manganic oxide with the manganese content of 70.1 percent and the granularity D50 of 9.7 mu m, 310g of lithium hydroxide with the particle size of less than 1mm and the content of 56.5 percent and 3L of pure water into a nickel-lined pressure reaction kettle with the volume of 5L according to the proportion of the solid-liquid mass ratio of the manganous-manganic oxide to the water 1:3, introducing high-pressure oxygen, continuously introducing the oxygen into the pressure reaction kettle, introducing oxygen when the temperature of reaction materials begins to rise, and performing air exhaust operation in the pressure reaction kettle before introducing the oxygen; stirring and reacting for 7 hours at the temperature of 180 ℃ in the kettle and under the pressure of 2.0MPa of gauge pressure in the kettle, then cooling to below 80 ℃, removing a reaction product, carrying out suction filtration to obtain a wet material of a pre-lithium intercalation intermediate, and drying a filter cake for 24 hours at 120 ℃ to obtain a dry material of the pre-lithium intercalation intermediate.
Through detection, the granularity D50 of the pre-lithium intercalation intermediate is 10.2 mu m, and the dried material has the lithium content of 4.32 percent and the manganese content of 61.8 percent.
And (3) flatly paving 500g of the prepared lithium pre-embedding intermediate dry material in a mullite sagger, placing the sagger in an air atmosphere furnace, heating to 750 ℃ at a heating rate of more than 5 ℃/min, preserving heat for 5 hours, then, cutting off the power, cooling to below 100 ℃, discharging, and sieving the material with a 120-mesh sieve to obtain 503g of the lithium manganate cathode material. Through detection, the particle size D50 of the lithium manganate positive electrode material is 11.1 μm, the lithium content is 4.21%, the manganese content is 59.9%, and the molar ratio of lithium to manganese is 0.55.
FIG. 12 is an XRD pattern of the pre-intercalated lithium intermediate of this example, indicating that the pre-intercalated lithium intermediate product is prepared from Mn 3 O 4 With Li phase 2 MnO 3 Phase composition.
By comparing the trimanganese tetroxide raw material, the prepared pre-lithiated intermediate product, and the finally prepared lithium manganate product in the present example by particle size distribution diagrams (see fig. 7, 8, and 9), it was found that the particle size distributions of the pre-lithiated intermediate product (having a particle size D50 of 10.2 μm) and the trimanganese tetroxide raw material (having a particle size D50 of 9.7 μm) were substantially identical, and the finally prepared lithium manganate positive electrode material also substantially followed the particle size distributions of the pre-lithiated intermediate product and the trimanganese tetroxide raw material, having a particle size D50 of 11.1 μm.
And comparing the trimanganese tetroxide raw material, the prepared pre-lithium intercalation intermediate product and the finally prepared lithium manganate product in the embodiment by using an SEM image of a microscopic appearance, wherein the trimanganese tetroxide raw material, the pre-lithium intercalation intermediate product and the finally prepared lithium manganate product are all regular spherical particles, the microscopic appearance is good, and the uniformity and the consistency of the product are good.
Based on the above detection and analysis, we believe that the above example produces a manganomanganic pre-intercalated lithium intermediate comprising a manganomanganic oxide phase and a pre-intercalated lithium element that is lithium manganese oxide (Li) 2 MnO 3 ) The phase is coated or inserted into a manganomanganic oxide phase, and the molar ratio of the pre-inserted lithium element in the pre-inserted lithium intermediate to the manganese element therein is consistent with the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared based on the pre-inserted lithium intermediate (0.55. The oxidation of manganese element can be roughly judged by comparing the precursor trimanganese tetroxide, the pre-lithium intercalation intermediate and the synthesized lithium manganate material.
Table 3: in this example, the ratio of the components of the precursor, the intermediate and the lithium manganate is changed
In this example, the chemical formula of the lithium manganate product finally prepared is Li 1.1 Mn 2 O 4 。
And (3) carrying out electricity-buckling detection on the lithium manganate obtained by the preparation:
the detection results are as follows:
the capacity of 0.2C g is 115mAh/g, the capacity of 1C is 114mAh/g, the capacity retention rate is 95 percent after 50 times of circulation at 25 ℃, and the capacity retention rate is 91 percent after 100 times.
Example 4:
the invention relates to a preparation method of a manganous manganic oxide pre-lithium intercalation intermediate, which comprises the following steps:
adding 2000g of spherical trimanganese tetroxide with the manganese content of 70.1 percent and the granularity D50 of 10.4 mu m, 606g of lithium hydroxide with the particle size of less than 1mm and the content of 56.5 percent and 5L of pure water into a nickel-lined pressure reaction kettle with the volume of 10L according to the proportion of trimanganese tetroxide to water, introducing high-pressure oxygen into the pressure reaction kettle continuously, introducing oxygen when the temperature of reaction materials is raised, and exhausting air in the pressure reaction kettle before introducing oxygen; stirring and reacting for 6 hours at the temperature of 180 ℃ in the kettle and under the pressure of 2.0MPa of gauge pressure in the kettle, then cooling to below 80 ℃, removing a reaction product, carrying out suction filtration to obtain a wet material of a pre-lithium intercalation intermediate, and drying a filter cake for 24 hours at 120 ℃ to obtain a dry material of the pre-lithium intercalation intermediate.
The detection shows that the particle size D50 of the pre-lithium intercalation intermediate is 9.9 mu m, the lithium content is 4.27 percent and the manganese content is 62.0 percent.
And (2) spreading 500g of the prepared lithium pre-embedding intermediate dry material in a mullite sagger, placing the sagger in an air atmosphere furnace, heating to 790 ℃ at a heating rate of more than 5 ℃/min, preserving the heat for 5 hours, then, cutting off the power, cooling to below 100 ℃, discharging, and sieving the material with a 120-mesh sieve to obtain 515g of the lithium manganate cathode material. Through detection, the particle size D50 of the lithium manganate positive electrode material is 10.9 μm, the lithium content is 4.16%, the manganese content is 60.2%, and the lithium-manganese molar ratio is 0.54.
FIG. 13 is an XRD pattern of the pre-intercalated lithium intermediate of this example, indicating that the pre-intercalated lithium intermediate product is prepared from Mn 3 O 4 Phase and Li 2 MnO 3 Phase composition.
By comparing the trimanganese tetroxide raw material, the prepared pre-intercalated lithium intermediate product and the finally prepared lithium manganate product in the present example by the particle size distribution diagram, it was found that the particle size distribution of the pre-intercalated lithium intermediate product (the particle size D50 of which is 9.9 μm) and the trimanganese tetroxide raw material (the particle size D50 of which is 10.4 μm) were substantially uniform, and the finally prepared lithium manganate positive electrode material also substantially followed the particle size distribution of the pre-intercalated lithium intermediate product and the trimanganese tetroxide raw material, the particle size D50 of which was 10.9 μm.
And comparing the trimanganese tetroxide raw material, the prepared pre-lithium intercalation intermediate product and the finally prepared lithium manganate product in the embodiment by using an SEM image of the micro-morphology, wherein the trimanganese tetroxide raw material, the pre-lithium intercalation intermediate product and the finally prepared lithium manganate product are all regular spherical particles, the micro-morphology is good, and the uniformity and the consistency of the product are good.
Based on the above detection and analysis, we believe that the above example produces a manganomanganic pre-intercalated lithium intermediate comprising a manganomanganic oxide phase and a pre-intercalated lithium element that is lithium manganese oxide (Li) 2 MnO 3 ) The phase is coated or inserted into a manganomanganic oxide phase, and the molar ratio of the pre-inserted lithium element in the pre-inserted lithium intermediate to the manganese element therein is consistent with the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared based on the pre-inserted lithium intermediate (0.54. The oxidation of the manganese element can also be roughly judged by comparing the precursor trimanganese tetroxide, the pre-lithium intercalation intermediate and the synthesized lithium manganate material, which shows that the manganese element is partially oxidized by the introduced oxygen during the synthesis of the pre-lithium intercalation intermediate.
Table 4: in this example, the ratio of the components of the precursor, the intermediate and the lithium manganate is changed
In this example, the chemical formula of the lithium manganate product finally prepared is Li 1.08 Mn 2 O 4 。
And (3) carrying out electricity-buckling detection on the lithium manganate obtained by the preparation:
the detection results are as follows:
the capacity of 0.2C g is 121mAh/g, the capacity of 1C is 120mAh/g, the capacity retention rate is 94 percent after 50 times of circulation at 25 ℃, and the capacity retention rate is 91 percent after 100 times.
As shown in FIG. 19, which is a XRD contrast diagram of the pre-intercalated lithium intermediates of the above examples, it can be seen from FIG. 19 that the XRD diagrams of the intermediates have common characteristic peaks and contain Mn despite the different amounts of pre-intercalated lithium 3 O 4 With Li phase 2 MnO 3 Phase, and the XRD diffraction pattern of the main pre-lithium intercalation intermediate has a diffraction peak with the intensity of more than 600cps at the position of 18.5 +/-0.5 degrees in 2 theta; 2 theta has a diffraction peak having an intensity of greater than 400cps or at least greater than 200cps at 44.5 DEG + -0.5 DEG, and 2 theta has at least 3-4 diffraction peaks having an intensity in the range of 80-260cps in the range of 58 DEG-66 deg.
Claims (16)
1. The pre-lithium intercalation intermediate is characterized by comprising a trimanganese tetroxide phase and a pre-intercalated lithium element, wherein the lithium element is coated or intercalated in the trimanganese tetroxide phase by a lithium manganese oxide phase, and the molar ratio of the pre-intercalated lithium element in the pre-lithium intercalation intermediate to the manganese element in the pre-lithium intercalation intermediate is consistent with the stoichiometric ratio of the lithium element to the manganese element in a target lithium manganate material prepared based on the pre-intercalated lithium intermediate.
2. The manganomanganic pre-lithium intercalation intermediate of claim 1, wherein the valence state of manganese in the lithium manganese oxide phase is higher than the average valence state of manganese in manganomanganic oxide.
3. The manganomanganic pre-lithium intercalation intermediate of claim 2, wherein the lithium manganese oxide comprises Li 2 MnO 3 。
4. The manganomanganic pre-lithium intercalation intermediate of claim 1, wherein the pre-lithium intercalation intermediate has an XRD diffraction pattern with a 2 Θ diffraction peak at 18.5 ° ± 0.5 ° with an intensity greater than 600 cps; the 2 theta has a diffraction peak with an intensity of more than 200cps at 44.5 DEG + -0.5 DEG, and the 2 theta has at least three diffraction peaks with an intensity of 80-260cps in the range of 58-66 deg.
5. The manganomanganic pre-lithium intercalation intermediate as claimed in any one of claims 1 to 4, wherein the pre-lithium intercalation intermediate is prepared by the hydrothermal reaction of manganomanganic oxide and a lithium source under the condition of oxygen introduction.
6. A preparation method of a manganomanganic oxide pre-lithium intercalation intermediate comprises the following steps:
putting manganous-manganic oxide, a lithium source and water into a pressure reaction kettle, controlling the temperature in the kettle to be more than 100 ℃ and the internal pressure of the kettle to be more than 0.1MPa under the condition of introducing oxygen, and fully and completely reacting under the stirring condition to obtain a pre-intercalated lithium intermediate;
the input amount of the lithium source is determined according to the stoichiometric ratio of the lithium element to the manganese element in the target lithium manganate material prepared by the pre-lithium intercalation intermediate.
7. The method of claim 6, wherein the lithium source is lithium hydroxide.
8. The method of claim 7, wherein the lithium hydroxide is in the form of particles having a diameter of less than 10 mm.
9. The method according to any one of claims 6 to 8, wherein the mass ratio of the trimanganese tetroxide to the water is controlled to be 1: 0.3-10.
10. The method according to any one of claims 6 to 8, wherein the temperature in the reaction vessel is controlled to 110 to 250 ℃ and the reaction time is controlled to 4 to 12 hours.
11. The preparation method according to any one of claims 6 to 8, wherein the gauge pressure in the autoclave is controlled to be 0.2 to 5.0MPa, and the pressure in the autoclave after the introduction of oxygen exceeds the saturated vapor pressure of water vapor at the corresponding temperature in the autoclave.
12. The process according to any one of claims 6 to 8, wherein the introduction of oxygen into the autoclave is carried out continuously, and wherein oxygen is introduced from the start of the temperature rise of the reaction material and the inside of the autoclave is purged before the introduction of oxygen.
13. The use of the manganous manganic oxide pre-lithium intercalation intermediate of any one of claims 1 to 5, wherein dry materials or wet materials of the pre-lithium intercalation intermediate are roasted in an oxygen atmosphere, and after the roasting is completed and the crystal structure conversion is completed, the spinel type lithium manganate cathode material is obtained.
14. The use according to claim 13, wherein the wet material of the pre-intercalated lithium intermediate is selected for calcination and has a water content of less than 30%.
15. Use according to any one of claims 13 to 14, wherein the calcination temperature is 700 ℃ to 850 ℃ and the calcination time is 3 to 10 hours.
16. Use according to any one of claims 13 to 14, characterised in that the firing temperature range is reached by rapid ramping at a ramp rate of more than 5 ℃/minute.
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| PCT/CN2022/092208 WO2023184656A1 (en) | 2022-03-28 | 2022-05-11 | Trimanganese tetraoxide lithium pre-embedded intermediate, preparation method therefor and use thereof |
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| CN1482068A (en) * | 2002-09-10 | 2004-03-17 | 中南大学 | Wet chemical synthesis of positive electrode material of Li-ion battery |
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| JPH11180717A (en) * | 1997-12-22 | 1999-07-06 | Ishihara Sangyo Kaisha Ltd | Lithium manganate, its production and lithium cell produced by using the same |
| CN109088115B (en) * | 2018-07-24 | 2020-07-17 | 广东光华科技股份有限公司 | Method for preparing ternary cathode material by recycling waste lithium ion battery cathode material |
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