CN116487563A - Surface modified sodium ion battery positive electrode material and preparation method and application thereof - Google Patents
Surface modified sodium ion battery positive electrode material and preparation method and application thereof Download PDFInfo
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- CN116487563A CN116487563A CN202310551196.2A CN202310551196A CN116487563A CN 116487563 A CN116487563 A CN 116487563A CN 202310551196 A CN202310551196 A CN 202310551196A CN 116487563 A CN116487563 A CN 116487563A
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- 239000007774 positive electrode material Substances 0.000 title claims abstract description 92
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical class [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 title claims abstract description 77
- 238000002360 preparation method Methods 0.000 title claims abstract description 23
- 229910001415 sodium ion Inorganic materials 0.000 claims abstract description 32
- 239000010405 anode material Substances 0.000 claims abstract description 27
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000011737 fluorine Substances 0.000 claims abstract description 19
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 19
- 229920000642 polymer Polymers 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 18
- 239000003960 organic solvent Substances 0.000 claims abstract description 9
- 239000002245 particle Substances 0.000 claims abstract description 6
- 239000012798 spherical particle Substances 0.000 claims abstract description 4
- 239000002033 PVDF binder Substances 0.000 claims description 35
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 35
- 238000000498 ball milling Methods 0.000 claims description 22
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 21
- 229920002313 fluoropolymer Polymers 0.000 claims description 15
- 239000004811 fluoropolymer Substances 0.000 claims description 15
- 239000010406 cathode material Substances 0.000 claims description 14
- 238000011282 treatment Methods 0.000 claims description 13
- 238000003756 stirring Methods 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 9
- -1 nickel iron sodium manganate Chemical compound 0.000 claims description 9
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 8
- 238000000967 suction filtration Methods 0.000 claims description 7
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 238000000926 separation method Methods 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 238000012986 modification Methods 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims description 2
- 238000004381 surface treatment Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 32
- 239000003513 alkali Substances 0.000 abstract description 15
- 239000011734 sodium Substances 0.000 abstract description 13
- 230000008569 process Effects 0.000 abstract description 9
- 230000002829 reductive effect Effects 0.000 abstract description 9
- 230000005661 hydrophobic surface Effects 0.000 abstract description 7
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 abstract description 6
- 239000011230 binding agent Substances 0.000 abstract description 6
- 229910052708 sodium Inorganic materials 0.000 abstract description 6
- 238000000265 homogenisation Methods 0.000 abstract description 5
- 230000002209 hydrophobic effect Effects 0.000 abstract description 2
- 239000003570 air Substances 0.000 description 20
- 239000011572 manganese Substances 0.000 description 20
- 239000000243 solution Substances 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- WFSRWJJESXWWSH-UHFFFAOYSA-N [O-2].[Fe+2].[Mn+2].[Ni+2].[Na+] Chemical compound [O-2].[Fe+2].[Mn+2].[Ni+2].[Na+] WFSRWJJESXWWSH-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000011259 mixed solution Substances 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000011324 bead Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000011258 core-shell material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000002687 intercalation Effects 0.000 description 2
- 238000009830 intercalation Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 229910000314 transition metal oxide Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical group 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000005414 inactive ingredient Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- DMTIXTXDJGWVCO-UHFFFAOYSA-N iron(2+) nickel(2+) oxygen(2-) Chemical compound [O--].[O--].[Fe++].[Ni++] DMTIXTXDJGWVCO-UHFFFAOYSA-N 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- LBSANEJBGMCTBH-UHFFFAOYSA-N manganate Chemical compound [O-][Mn]([O-])(=O)=O LBSANEJBGMCTBH-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 150000003385 sodium Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910001428 transition metal ion Inorganic materials 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- 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
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- 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
- H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
-
- 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
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- 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
-
- 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
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
- H01M4/623—Binders being polymers fluorinated polymers
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- 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)
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Abstract
The invention provides a surface modified sodium ion battery positive electrode material, a preparation method and application thereof, wherein the surface modified sodium ion battery positive electrode material takes a conventional sodium ion battery positive electrode material as a core, and a layer of organic fluorine polymer is wrapped on the surface of the surface modified sodium ion battery positive electrode material; the conventional sodium ion battery anode material is mixed and doped by large and small spherical particles, the particle size is 2-10 mu m, and the thickness of the organic fluorine polymer on the surface of the core is 0.1-2 mu m. The hydrophobic surface of the fluorine-containing polymer is formed on the surface of the positive electrode material of the sodium battery, so that the affinity of the material to moisture is reduced, and the good hydrophobic performance of the material is realized; in addition, the fluorine-containing polymer can be used as a binder, and the fluorine-containing polymer on the surface of the positive electrode material can be dissolved in an organic solvent in the cell homogenization process stage to play a role in binding. The surface modified sodium ion battery anode material can effectively protect the battery anode material and reduce the residual alkali residue on the surface.
Description
Technical Field
The invention belongs to the technical field of sodium ion batteries, and relates to a surface modified sodium ion battery anode material, a preparation method and application thereof.
Background
With the gradual exposure of lithium ion battery deficiency, sodium ion batteries are increasingly researched. Among the numerous candidates for positive electrode materials, O3-type Na-based layered transition metal oxide NaTMO is preferred due to its excellent electrochemical activity and simple synthesis process 2 (where TM = transition metal, e.g., co, ni, mn, fe, etc.) is considered one of the most potential candidates. However, when exposed to air, the capacity of the O3 type positive electrode is rapidly reduced due to spontaneous extraction of Na, oxidation of transition metal, and the like. In addition, the poor air stability of the O3 type Na-based layered transition metal oxide also greatly improves the manufacturing cost of the sodium battery for storing, transporting and using the material, and greatly limits the practical application of the O3 type oxide.
Publication number CN115403079a discloses that oxidation intercalation of active ions (mixed calcination with active ion-containing compounds) is performed on a positive electrode precursor material to obtain a positive electrode active material, and chemical property optimization and physical isolation are used as an entry point to improve the deintercalation capability of active ions and reduce the probability of side reactions with water oxygen and electrolyte.
Publication No. CN115377389A discloses that an effective membrane layer is formed between a material and air or electrolyte by doping a specific amount of sulfur element, so that the material has better interface stability and the occurrence of interface side reactions is reduced.
Publication No. CN115275180A discloses a vacancy type sodium ion positive electrode material, which is characterized in that proper Na vacancies are introduced into an O3 type material and Li doping is carried out, so that the problems of high surface residual alkali and poor doubling rate are solved, and the specific capacity of the material is further improved. In addition, the positive electrode material has higher specific capacity, good air stability, rate capability and cycle stability. In addition, proper Na vacancies in the crystal structure not only can effectively improve the chemical stability of the layered oxide to the ambient air, but also can improve the mobility of Na in the process of removal/intercalation without sacrificing the capacity. In addition, na vacancies can also increase the valence state of transition metal ions, thereby enhancing the oxidation resistance of the material and inhibiting adverse spontaneous reactions between the material and air. In addition, the air stability of the material can be improved to a certain extent by coating, F doping, phosphate radical introduction and the like.
However, the above coating treatments all result in the introduction of other impurities or inactive ingredients into the positive electrode active material, affecting the specific energy of the positive electrode.
In addition, the active oxygen anions on the surface of the positive electrode material can react with CO in the air 2 React with moisture to generate carbonate, and the generated carbonate can be easily combined with sodium ions which migrate from the body to the surface and form Na on the surface of the material 2 CO 3 This process is accompanied by deoxidization of the material surface to form a structurally distorted surface oxide layer. Too high a residual alkali content on the surface of the positive electrode material can have a number of negative effects on electrochemical performance. Firstly, it affects the coating, and because the basic oxide content on the surface of the material is too high, it causes water absorption, and thus it is easy to form jelly-like during the homogenization process. And secondly, sodium carbonate on the surface of the positive electrode material is decomposed under high voltage, which is one of the main reasons for the gas expansion of the battery, thereby bringing about hidden danger in the aspect of safety. The effect of surface alkaline compounds on electrochemical performance is mainly manifested by increased irreversible capacity loss while deteriorating cycle performance. Therefore, the reduction of the residual alkali content on the surface is of great importance for the practical application of ternary materials in power batteries.
Therefore, it is necessary to provide a surface-modified positive electrode material for sodium ion battery, which can effectively improve the high residual alkali characteristic of the positive electrode surface of the layered oxide of sodium ion battery and improve the long-term stability of the positive electrode material by simple treatment of the existing positive electrode material, has no influence on the performance of the positive electrode active material itself and does not need to add additional treatment procedures when the positive electrode material is used.
Disclosure of Invention
Based on the above-mentioned drawbacks of the prior art, a first object of the present invention is to provide a surface-modified positive electrode material for sodium-ion batteries; the second object of the invention is to provide a method for preparing the surface modified sodium ion battery anode material; a third object of the invention is to provide the use of the surface modified positive electrode material for sodium ion batteries.
The aim of the invention is achieved by the following technical means:
in one aspect, the invention provides a surface modified sodium ion battery positive electrode material, which takes a conventional sodium ion battery positive electrode material as a core, and a layer of organic fluorine polymer is wrapped on the surface of the core; the conventional sodium ion battery anode material is mixed and doped by large and small spherical particles, the particle size is 2-10 mu m, and the thickness of the organic fluorine polymer on the surface of the core is 0.1-2 mu m.
In the surface-modified sodium ion battery cathode material described above, preferably, the conventional sodium ion battery cathode material includes a nickel iron sodium manganate cathode material and/or a copper iron sodium manganate cathode material, but is not limited thereto.
In the surface-modified positive electrode material for sodium ion battery, preferably, the conventional positive electrode material for sodium ion battery is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 And a positive electrode material.
In the surface-modified sodium ion battery cathode material described above, preferably, the organic fluoropolymer includes polyvinylidene fluoride (PVDF) and/or Polytetrafluoroethylene (PTFE); but is not limited thereto.
In another aspect, the present invention also provides a method for preparing a surface-modified positive electrode material for sodium ion batteries, the method comprising:
and carrying out surface modification on the conventional sodium ion battery positive electrode material by utilizing the organic fluoropolymer to obtain the surface modified sodium ion battery positive electrode material, wherein the surface treatment is dry treatment or wet treatment.
In the traditional method, the coating doping is adopted to improve the interface or bulk phase structure to inhibit residual alkali, so that the sodium-electricity positive electrode material with low original capacity can further reduce the capacity, and the sodium battery is not beneficial to advancing in the capacity direction. Based on the above, after the sintering of the positive electrode material is finished, the hydrophobic surface of the specific material is formed on the surface of the positive electrode material, so that the affinity of the material to moisture is reduced, the stability of the material in air is improved, and the material can be stored in air for a long time. The material is coated by using a specific fluorine-containing polymer, so that the conventional positive electrode material is separated from air, and active oxygen anions on the surface of the positive electrode material and CO in the air are effectively prevented 2 And the contact of water effectively prevents carbonate radicals generated by mutual reaction and reduces residual alkali on the surface of the material.
In addition, the fluorine-containing polymer can be used as a binder besides the effects of hydrophobicity and air isolation, and when the cathode material is used for manufacturing an electrode, the fluorine-containing polymer on the surface of the material can be dispersed in an organic solvent in a homogenization process stage to play a role in binding, so that the use of the binder in a battery pulping stage can be properly reduced, and the improvement of the overall specific energy of the battery cell is facilitated.
In the above preparation method, preferably, the dry treatment step includes:
and mixing the conventional sodium ion battery anode material with an organic fluorine polymer, and performing ball milling to obtain the surface modified sodium ion battery anode material after ball milling.
In the above preparation method, preferably, the mass ratio of the conventional sodium ion battery positive electrode material to the organic fluorine polymer is (50 to 10000): 1.
in the above preparation method, preferably, the ball milling is performed at a speed of 50 to 500rpm; the ball milling time is 1-20 h.
In the above preparation method, preferably, the wet treatment step includes:
dispersing the organic fluorine polymer into an organic solvent, and uniformly mixing to obtain an organic solution;
adding the anode material of the conventional sodium ion battery into an organic solution, stirring at constant temperature, dispersing uniformly, and carrying out suction filtration;
and fully drying the solid matters subjected to suction filtration and separation to obtain the surface modified sodium ion battery anode material.
In the above preparation method, preferably, the volume ratio of the organic fluoropolymer to the organic solvent is 1: (1-10000).
In the above preparation method, preferably, the mass ratio of the conventional sodium ion battery positive electrode material to the organic solution is 1: (20-1000).
In the above preparation method, preferably, the constant temperature stirring temperature is 20-100 ℃, the stirring speed is 50-500 rpm, and the stirring time is 1-20 h.
In the above preparation method, preferably, the drying temperature is 40-200 ℃ and the drying time is 5-20 h.
In the above preparation method, preferably, the organic solvent is selected from one or more of ethanol, dimethyl sulfoxide (DMSO) and N-methylpyrrolidone (NMP), but is not limited thereto.
In still another aspect, the invention also provides an application of the surface modified sodium ion battery anode material in a sodium ion battery.
The invention has the beneficial effects that:
after the sintering of the positive electrode material is finished, the hydrophobic surface is manufactured on the surface of the positive electrode material, so that the affinity of the material and moisture is reduced, the stability of the material in air is improved, and the material can be stored in the air for a long time. The material is coated by using a specific fluorine-containing polymer, so that the conventional positive electrode material is separated from air, and active oxygen anions on the surface of the positive electrode material and CO in the air are effectively prevented 2 And the contact of water effectively prevents carbonate radicals generated by mutual reaction and reduces residual alkali on the surface of the material. In addition, the fluoropolymer can be used as a binder in addition to its hydrophobic and air-insulating properties, and the surface of the material can be impregnated with the fluoropolymer during the homogenization process when the positive electrode material is used to make an electrodeThe fluoropolymer can be dispersed in an organic solvent to play a role in bonding, which can also properly reduce the use of the binder in the battery pulping stage and also contribute to the improvement of the overall specific energy of the battery.
The method is simple to operate, does not need to introduce complex working procedures, and can directly carry out continuous operation in the preparation process of the anode material. The obtained material has good stability and can be stored for a long time without special treatment.
Drawings
Fig. 1 is a schematic diagram of a core-shell structure of a surface modified sodium ion battery positive electrode material prepared by the invention.
Fig. 2 is an SEM image (3500X) of the surface-modified sodium ion battery cathode material prepared in example 61 of the present invention.
Fig. 3 is an SEM image (5000X) of the surface-modified sodium ion battery cathode material prepared in example 6 of the present invention.
Detailed Description
The technical solution of the present invention will be described in detail below for a clearer understanding of technical features, objects and advantageous effects of the present invention, but should not be construed as limiting the scope of the present invention. The raw materials in the following examples are all commercially available in the art unless otherwise specified.
Example 1:
the present example provides a surface-modified sodium ion battery positive electrode material having a layered oxide sodium nickel iron manganese oxide positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the core-shell structure schematic diagram of the surface modified sodium ion battery anode material is shown in fig. 1, wherein the central core is layered oxide sodium nickel iron manganese oxide, the outer coating shell is polyvinylidene fluoride, and the specific expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @0.5％PVDF。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) 10g of sintered NaNi is taken 1/3 Fe 1/3 Mn 1/3 O 2 The positive electrode material is formed by a process of forming a positive electrode material,weighing PVDF mixed with 0.05g, and placing the mixture in a ball mill;
(2) Ball milling is carried out by adding ball milling beads, the rotating speed is 300rpm/min, and the ball milling is maintained for 3 hours;
(3) And (5) after ball milling, obtaining the surface modified sodium ion battery anode material.
SEM experiments were performed on the surface-modified sodium ion battery cathode material prepared in this example 1, and the results are shown in fig. 2.
As shown in FIG. 2, the conventional sodium battery positive electrode material is formed by mixing spherical particles with the size of about 10 mu m and about 2-4 mu m, and the sodium battery positive electrode material and PVDF are subjected to ball milling and mixing, and the PVDF particles can be smashed by the ball milling treatment and uniformly mixed with the positive electrode particles, and finally the spherical positive electrode particles are coated with the PVDF with the thickness of about 0.1 mu m. Through the hydrophobicity of PVDF, the sodium-electricity positive electrode material can be effectively protected, contact with water and air is avoided, and the generation of residual alkali on the surface is inhibited.
Example 2:
the present example provides a surface-modified sodium ion battery positive electrode material having a layered oxide sodium nickel iron manganese oxide positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the concrete expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @1％PVDF。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) 10g of sintered NaNi is taken 1/3 Fe 1/3 Mn 1/3 O 2 The positive electrode material is weighed and mixed with 0.1g PVDF, and the mixture is placed in a ball mill;
(2) Ball milling is carried out by adding ball milling beads, the rotating speed is 500rpm/min, and the ball milling is maintained for 10 hours;
(3) And (5) after ball milling, obtaining the surface modified sodium ion battery anode material.
Example 3:
the present example provides a surface-modified sodium ion battery positive electrode material having nickel-iron oxide in the form of a layered oxideSodium manganate positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the concrete expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @2％PVDF。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) 10g of sintered NaNi is taken 1/3 Fe 1/3 Mn 1/3 O 2 The positive electrode material is weighed and mixed with 0.2g PVDF, and the mixture is placed in a ball mill;
(2) Ball milling is carried out by adding ball milling beads, the rotating speed is 500rpm/min, and the ball milling is maintained for 20 hours;
(3) And (5) after ball milling, obtaining the surface modified sodium ion battery anode material.
Example 4:
the present example provides a surface-modified sodium ion battery positive electrode material having a layered oxide sodium nickel iron manganese oxide positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the concrete expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @1％PVDF(sol)。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) Mixing 1g of PVDF with 100ml of ethanol solution to obtain an organic solution;
(2) 10g of NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Adding a positive electrode material into the organic solution to obtain a mixed solution;
(3) The obtained mixed solution is stirred for 30min at a constant temperature of 25 ℃ and a speed of 100 rpm;
(4) After stirring, carrying out suction filtration separation, and fully drying the separated solid at 80 ℃ for 10 hours to obtain the hydrophobic surface modified sodium ion battery positive electrode material.
Example 5:
this example provides a surface-modified positive electrode material for sodium ion batteriesIt has a layered oxide sodium nickel iron manganese oxide positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the concrete expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @1％PVDF(sol)。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) Mixing 1g of PVDF and 100ml of N-methylpyrrolidone (NMP) solution to obtain an organic solution;
(2) 10g of NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Adding a positive electrode material into the organic solution to obtain a mixed solution;
(3) The obtained mixed solution is stirred for 30min at a constant temperature of 25 ℃ and a speed of 100 rpm;
(4) After stirring, carrying out suction filtration separation, and fully drying the separated solid at 120 ℃ for 10 hours to obtain the hydrophobic surface modified sodium ion battery positive electrode material.
Example 6:
the present example provides a surface-modified sodium ion battery positive electrode material having a layered oxide sodium nickel iron manganese oxide positive electrode material NaNi 1/3 Fe 1/3 Mn 1/3 O 2 As a core, the surface is coated with a layer of organic fluoropolymer polyvinylidene fluoride (PVDF); the concrete expression is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 @2％PVDF(sol)。
The preparation method of the surface modified sodium ion battery anode material comprises the following steps:
(1) Mixing 2g of PVDF and 100ml of N-methylpyrrolidone (NMP) solution to obtain an organic solution;
(2) 10g of NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Adding a positive electrode material into the organic solution to obtain a mixed solution;
(3) The obtained mixed solution is stirred for 30min at a constant temperature of 25 ℃ and a speed of 100 rpm;
(4) After stirring, carrying out suction filtration separation, and fully drying the separated solid at 120 ℃ for 10 hours to obtain the hydrophobic surface modified sodium ion battery positive electrode material.
SEM experiments were performed on the hydrophobic surface modified sodium ion battery cathode material prepared in this example 6, and the experimental results are shown in fig. 3. The element content in the black circles in fig. 3 is shown in table 1.
Table 1 elemental content in black circles in fig. 3
As shown in fig. 3, the sodium-electricity positive electrode material obtained by dispersing the positive electrode material in PVDF solution and then drying the same was coated with a film-like substance on the surface, and after elemental analysis, it was found that F was contained, which proved that the surface was coated with PVDF substance.
Comparative example 1:
untreated NaNi 1/3 Fe 1/3 Mn 1/3 O 2 。
Performance test:
the sodium-electricity cathode materials of the above examples and comparative example 1 were placed in a 20% humidity environment for 5 hours, the materials before and after the placement were subjected to moisture and residual alkali tests, and the cathode materials before and after the placement were subjected to evaluation of electrochemical properties, 0.2C charge and discharge in the interval of 2.0V to 4.0V, and experimental results are shown in tables 2 and 3.
TABLE 2 measurement results of moisture and residual alkali
| Experiment number | Water content ppm before standing | Water ppm after standing | Residual alkali before standing% | Residual alkali after standing% |
| Example 1 | 205 | 304 | 1.68 | 1.77 |
| Example 2 | 197 | 285 | 1.59 | 1.68 |
| Example 3 | 210 | 282 | 1.73 | 1.79 |
| Example 4 | 202 | 313 | 1.78 | 1.85 |
| Example 5 | 233 | 291 | 1.64 | 1.72 |
| Example 6 | 228 | 316 | 1.62 | 1.69 |
| Comparative example 1 | 252 | 1867 | 1.72 | 5.15 |
As shown in table 2, the water content was about 200ppm before being placed in the environment with 20% humidity, and the water content was increased to different degrees after being placed in the environment with 20% humidity for 5 hours, and as compared with comparative example 1, the PVDF and the sodium positive electrode material were combined with each other to effectively enhance the hydrophobicity of the material, and as compared with the results of the front and rear residual alkali contents, it was found that the residual alkali content on the surface of the modified sodium positive electrode material was reduced compared with the original material of comparative example 1, indicating that the air stability was enhanced.
TABLE 3 evaluation of electrochemical Properties of cathode materials before and after 5 hours of storage in 20% humidity Environment
As shown in table 3, by comparing the first-turn discharge gram capacity and the first-turn efficiency of the half cell of the sodium-electric positive electrode material before being placed, the PVDF-modified sodium-electric positive electrode material did not affect its capacity exertion, indicating that it can be completely dissolved in NMP during the homogenization process, as a binder; the electrochemical performance of the positive electrode material is tested after the positive electrode material is placed, the capacity of the comparative example 1 is obviously reduced and only 120.5mAh/g, and the gram capacity loss of the positive electrode material is obviously reduced through the modified example, and the modified positive electrode material has relatively stable gram capacity and first-effect retention rate, so that the positive electrode material is relatively good in long-time stability in air. Therefore, the invention provides the sodium-electricity layered oxide with high air stability without sacrificing gram capacity and the modification method thereof.
The above examples describe in detail preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A surface modified sodium ion battery positive electrode material takes a conventional sodium ion battery positive electrode material as a core, and a layer of organic fluorine polymer is wrapped on the surface of the core; the conventional sodium ion battery anode material is mixed and doped by large and small spherical particles, the particle size is 2-10 mu m, and the thickness of the organic fluorine polymer on the surface of the core is 0.1-2 mu m.
2. The surface modified sodium ion battery positive electrode material of claim 1, wherein the conventional sodium ion battery positive electrode material that is a core comprises a nickel iron sodium manganate positive electrode material and/or a copper iron sodium manganate positive electrode material; preferably NaNi 1/3 Fe 1/ 3 Mn 1/3 O 2 。
3. The surface modified sodium ion battery positive electrode material of claim 1, wherein the organic fluoropolymer comprises polyvinylidene fluoride and/or polytetrafluoroethylene.
4. A method of preparing the surface-modified sodium ion battery positive electrode material of any one of claims 1 to 3, the method comprising:
and carrying out surface modification on the conventional sodium ion battery positive electrode material by utilizing the organic fluoropolymer to obtain the surface modified sodium ion battery positive electrode material, wherein the surface treatment is dry treatment or wet treatment.
5. The preparation method according to claim 4, wherein the dry treatment step comprises:
and mixing the conventional sodium ion battery anode material with an organic fluorine polymer, and performing ball milling to obtain the surface modified sodium ion battery anode material after ball milling.
6. The preparation method according to claim 5, wherein the mass ratio of the conventional sodium ion battery positive electrode material to the organic fluorine polymer is (50 to 10000): 1.
7. the preparation method according to claim 5, wherein the ball milling speed is 50 to 500rpm; the ball milling time is 1-20 h.
8. The method of manufacturing according to claim 4, wherein the wet treatment step comprises:
dispersing the organic fluorine polymer into an organic solvent, and uniformly mixing to obtain an organic solution;
adding the anode material of the conventional sodium ion battery into an organic solution, stirring at constant temperature, dispersing uniformly, and carrying out suction filtration;
and fully drying the solid matters subjected to suction filtration and separation to obtain the surface modified sodium ion battery anode material.
9. The production method according to claim 8, wherein a volume ratio of the organic fluoropolymer to the organic solvent is 1: (1-10000);
preferably, the mass ratio of the conventional sodium ion battery positive electrode material to the organic solution is 1: (20-1000);
preferably, the constant temperature stirring temperature is 20-100 ℃, the stirring speed is 50-500 rpm, and the stirring time is 1-20 h;
preferably, the drying temperature is 40-200 ℃ and the drying time is 5-20 h;
preferably, the organic solvent is selected from one or more of ethanol, dimethyl sulfoxide and N-methyl pyrrolidone.
10. Use of the surface-modified sodium-ion battery cathode material according to any one of claims 1 to 3 in a sodium-ion battery.
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| CN117117158B (en) * | 2023-10-23 | 2024-01-23 | 浙江帕瓦新能源股份有限公司 | Modified sodium ion battery positive electrode material, preparation method thereof and sodium ion battery |
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