CN116995192A - Sodium-supplementing positive electrode plate, preparation method thereof and sodium ion battery - Google Patents
Sodium-supplementing positive electrode plate, preparation method thereof and sodium ion battery Download PDFInfo
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- CN116995192A CN116995192A CN202310983498.7A CN202310983498A CN116995192A CN 116995192 A CN116995192 A CN 116995192A CN 202310983498 A CN202310983498 A CN 202310983498A CN 116995192 A CN116995192 A CN 116995192A
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- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 229910001415 sodium ion Inorganic materials 0.000 title claims abstract description 16
- 238000002360 preparation method Methods 0.000 title abstract description 22
- 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 claims abstract description 98
- 239000011734 sodium Substances 0.000 claims abstract description 98
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 98
- 230000001502 supplementing effect Effects 0.000 claims abstract description 80
- 239000007774 positive electrode material Substances 0.000 claims abstract description 55
- 239000002002 slurry Substances 0.000 claims abstract description 46
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 16
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims abstract description 14
- 239000006258 conductive agent Substances 0.000 claims abstract description 12
- 229920000447 polyanionic polymer Polymers 0.000 claims abstract description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 36
- 239000011248 coating agent Substances 0.000 claims description 36
- 238000000576 coating method Methods 0.000 claims description 36
- 238000001035 drying Methods 0.000 claims description 22
- 238000002156 mixing Methods 0.000 claims description 20
- 239000000463 material Substances 0.000 claims description 19
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 17
- 239000011230 binding agent Substances 0.000 claims description 13
- 239000002904 solvent Substances 0.000 claims description 8
- BNBLBRISEAQIHU-UHFFFAOYSA-N disodium dioxido(dioxo)manganese Chemical compound [Na+].[Na+].[O-][Mn]([O-])(=O)=O BNBLBRISEAQIHU-UHFFFAOYSA-N 0.000 claims description 4
- 239000010405 anode material Substances 0.000 claims description 3
- 239000001509 sodium citrate Substances 0.000 claims description 3
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 3
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 claims description 3
- 229940039790 sodium oxalate Drugs 0.000 claims description 3
- 229940091252 sodium supplement Drugs 0.000 abstract description 11
- 230000008569 process Effects 0.000 abstract description 10
- 239000000853 adhesive Substances 0.000 abstract description 3
- 230000001070 adhesive effect Effects 0.000 abstract description 3
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 28
- 239000002033 PVDF binder Substances 0.000 description 27
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 27
- YPPMLCHGJUMYPZ-UHFFFAOYSA-L sodium;iron(2+);sulfate Chemical compound [Na+].[Fe+2].[O-]S([O-])(=O)=O YPPMLCHGJUMYPZ-UHFFFAOYSA-L 0.000 description 19
- 239000006185 dispersion Substances 0.000 description 14
- 238000005303 weighing Methods 0.000 description 14
- 229910052782 aluminium Inorganic materials 0.000 description 12
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 12
- 239000011888 foil Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000007605 air drying Methods 0.000 description 6
- 230000009469 supplementation Effects 0.000 description 6
- 238000001291 vacuum drying Methods 0.000 description 6
- QXNVGIXVLWOKEQ-UHFFFAOYSA-N Disodium Chemical compound [Na][Na] QXNVGIXVLWOKEQ-UHFFFAOYSA-N 0.000 description 4
- 238000005422 blasting Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910021385 hard carbon Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 230000002427 irreversible effect Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000010382 chemical cross-linking Methods 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical class [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
-
- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a sodium-supplementing positive electrode piece, a preparation method thereof and a sodium ion battery, and belongs to the technical field of sodium ion batteries. The sodium supplementing positive electrode plate comprises a current collector, a sodium supplementing layer and a positive electrode material layer which are sequentially arranged from inside to outside, wherein the positive electrode material layer does not contain sodium supplementing agent, the positive electrode material layer comprises sulfate polyanion type positive electrode materials, and the sodium supplementing layer comprises sodium supplementing agent, conductive agent and adhesive. The sodium-supplementing positive electrode plate provided by the invention can obviously improve the first charge-discharge capacity of the polyanionic positive electrode material. The sodium supplementing is realized, and meanwhile, the performance of the positive electrode material can be kept in the subsequent charge and discharge process. The preparation method provided by the invention avoids the problem that the positive electrode material and the sodium supplement directly interact in the traditional slurry preparation process, so that the slurry is gel-like and cannot be coated.
Description
Technical Field
The invention belongs to the technical field of sodium ion batteries, and particularly relates to a sodium-supplementing positive electrode piece, a preparation method thereof and a sodium ion battery.
Background
Because of the abundant sodium resource reserves and low price, the sodium ion battery has great application prospect in the fields of low-speed vehicles and energy storage. The positive electrode material of the sodium ion battery mainly comprises: polyanion system, transition metal layered oxide system and Prussian blue analogues, and the negative electrode is generally made of soft carbon or hard carbon materials. The sulfate material in the polyanion system has the advantages of low cost, stable structure, high working voltage, long cycle life, good heat stability, good safety and the like. However, when it is combined with a hard carbon negative electrode, it tends to cause generation of a large amount of irreversible capacity due to defect consumption of the hard carbon itself and formation of an SEI film upon first charge, thereby resulting in a low energy density of the full battery.
One of the solutions to the above problems is to supplement sodium to the positive electrode, so as to increase the first charge capacity, so as to ensure that the material can keep its original capacity in the subsequent charge-discharge cycle. The sodium supplement is mainly sodium salt, including sodium oxalate, sodium citrate, sodium carbonate and the like, and other positive electrode materials with high capacity and rapid decay can be considered as the sodium supplement.
However, since the sodium salt sodium supplement has strong alkalinity, when the sodium salt sodium supplement is directly homogenized with a sulfate material, the sodium salt sodium supplement and the sulfate material can interact to improve the activities of alkaline groups, free radicals and the like, so that the C-H and C-F in the adhesive polyvinylidene fluoride (PVDF) are attacked to perform elimination reaction, and a C=C double bond is formed to generate chemical crosslinking. Due to the high regularity of the PVDF chains, a continuous HF-removal reaction is liable to occur, eventually leading to gel formation of an alternating structure of single double bonds. The above situation causes the gel phenomenon of the positive electrode material in the process of homogenizing, and coating cannot be performed.
Disclosure of Invention
In order to overcome the above-mentioned difficulties, a first object of the present invention is to provide a sodium-supplementing positive electrode sheet, which avoids the interaction between the sodium-supplementing agent and the positive electrode material, and meets the requirement of effective sodium supplementation of sulfate polyanion materials.
The second aim of the invention is to provide a preparation method of the sodium-supplementing positive pole piece.
The third object of the invention is to provide a sodium ion battery using the sodium-supplementing positive electrode plate.
In order to achieve the above purpose, the technical scheme of the sodium supplementing positive electrode plate is as follows:
the utility model provides a sodium supplementing positive pole piece, includes the current collector and sets gradually sodium supplementing layer and positive material layer on the current collector from inside to outside, positive material layer does not contain the sodium supplementing agent, positive material layer includes sulphate formula polyanion formula positive material, sodium supplementing layer includes the sodium supplementing agent.
According to the invention, the positive electrode material layer and the sodium supplementing layer are arranged, so that the sulfate polyanion positive electrode material and the sodium supplementing agent are separated, the interaction between the positive electrode material and the sodium supplementing agent is avoided, sodium supplementing is realized, and the positive electrode material is ensured to keep the performance of the positive electrode material in the subsequent charge and discharge process.
The sodium-supplementing positive electrode plate provided by the invention can obviously improve the first charge-discharge capacity of the sulfate polyanion positive electrode material. Namely, in the formation process of the negative electrode SEI film, the sodium supplementing agent is used as a sacrificial sodium salt to contribute an irreversible capacity part, so that the electrochemical performance of the positive electrode material is kept unchanged as much as possible, and further, stable energy density is provided in the subsequent charge-discharge cycle.
In order to play a role of positive electrode sodium supplement, preferably, the sodium supplement is one or more selected from sodium carbonate, sodium citrate, sodium oxalate, sodium manganate positive electrode material and quaternary positive electrode material.
In order not to affect the exertion of the original capacity of the positive electrode material, the charge and discharge are stable in the subsequent electrochemical cycle, and preferably, the area density ratio of the sodium supplementing layer to the positive electrode material layer is 1:9-4:6.
In order to improve the adhesiveness and conductivity of the electrode and make the sodium supplementing effect more stable, preferably, the sodium supplementing agent in the sodium supplementing layer: conductive agent: the mass ratio of the binder is 80-96:4-10:2-5.
Preferably, the positive electrode material layer includes the sulfate type polyanionic positive electrode material, a conductive agent, and a binder, the sulfate type polyanionic positive electrode material: conductive agent: the mass ratio of the binder is 80-96:4-10:2-5.
The technical scheme of the preparation method of the sodium-supplementing positive electrode plate is as follows:
the preparation method of the sodium supplementing positive pole piece comprises the following steps:
s1: uniformly mixing a sodium supplementing agent, a conductive agent and a binder in a solvent to obtain slurry A;
s2: uniformly mixing the anode material, the conductive agent and the binder in a solvent to obtain slurry B;
s3: uniformly coating the slurry A on a current collector, and drying to obtain a pole piece A;
s4: and uniformly coating the slurry B on the pole piece A, and drying to obtain the pole piece B, namely the sodium supplementing positive pole piece.
The invention avoids the influence of the alkaline sodium supplement on the structure of the positive electrode material by adopting the process of respectively coating and drying the sodium supplement and the positive electrode material main material, solves the problem that the pole piece slurry cannot be normally coated, and can utilize a plurality of devices in the prior art by using the application process in the invention, thereby being easy to realize industrialized popularization.
In order to make the sodium-supplementing positive electrode sheet have excellent conductive performance, preferably, the conductive agent is selected from one or more of conductive graphite, conductive carbon black (SP), conductive carbon fiber and graphene.
In order to obtain a stable sodium-supplementing positive electrode sheet, the positive electrode sheet is in a stable state in an electrolyte for a long time, and preferably, the binder is one or two of polyvinylidene fluoride (PVDF) and modified nitrile rubber binders.
In order to thoroughly remove the organic solvent in the slurry, it is preferable that the drying temperature in the steps S3 and S4 is 100 to 150 ℃.
Preferably, the drying time in the step S3 is 0.5 to 2 hours, and the drying time in the step S4 is 0.5 to 12 hours.
The technical scheme of the sodium ion battery using the sodium-supplementing positive plate is as follows:
a sodium ion battery using the sodium-supplementing positive plate.
The sodium-supplementing positive plate provided by the invention is used as a positive electrode by adopting a conventional sodium ion battery construction method to construct a sodium ion battery.
The sodium ion battery is constructed by the sodium supplementing positive pole piece, the existing method and equipment can be used, the method and the equipment are simple and easy to implement, the sodium supplementing requirement of the positive pole material can be met, the loss of the original capacity of the positive pole material is reduced, and the original energy density of the battery is maintained.
Preferably, the sodium supplementing positive electrode plate and the metal sodium plate are utilized to assemble the rechargeable battery.
Drawings
Fig. 1 is a buckling curve of the sodium-supplementing positive electrode sheet provided in embodiment 1 of the present invention to metal sodium for the first time;
fig. 2 is a buckling curve of the sodium-supplementing positive electrode sheet to metal sodium for the first time provided in embodiment 2 of the present invention;
fig. 3 is a buckling curve of the sodium-supplementing positive electrode sheet provided in embodiment 3 of the present invention to metal sodium for the first time;
fig. 4 is a buckling curve of the sodium-supplementing positive electrode sheet provided in embodiment 4 of the present invention to metal sodium for the first time;
fig. 5 is a first charge-discharge curve of the buckling electricity of the sodium-supplementing positive electrode sheet to the metal sodium provided in embodiment 5 of the present invention;
FIG. 6 is a first charge-discharge curve of the sodium-supplemented positive electrode sheet provided in comparative example 2 to the buckling of metallic sodium;
FIG. 7 is a buckling cycle charge-discharge curve of the sodium-supplemented positive electrode sheet provided in example 1 of the present invention to metal sodium;
fig. 8 is a buckling cycle charge-discharge curve of the sodium-supplementing positive electrode sheet provided in embodiment 2 of the present invention with respect to metal sodium.
Detailed Description
In practical production, the invention discovers that when sodium is added to the sulfate positive electrode material, the sodium salt sodium adding agent and the sulfate material homogenate can generate a gel phenomenon, a pole piece can not be coated and formed, and the main directions for solving the problem by researching the principle of gel generation generally comprise: reducing the base content and removing the water content in the dry powder material; strictly controlling the environmental moisture in the process of homogenizing and coating; adding an additive to the slurry to neutralize alkalinity; PVDF modification, and the like. However, experiments show that the solution method is difficult to completely stop the crosslinking reaction of PVDF. When other types of adhesives are tried, the problem of poor adhesion arises. The invention sets the positive electrode material layer and the sodium supplementing layer while keeping the cohesiveness of the electrode plate, avoids the gel phenomenon of sodium supplementing agent and sulfate, plays the role of supplementing sodium of the sodium supplementing agent, and obtains the sodium supplementing positive electrode plate; and the preparation method is simple, can utilize the existing process equipment, and is easy to realize industrialized popularization.
The preparation method of the sodium supplementing positive pole piece comprises the following steps:
s1: uniformly mixing a sodium supplementing agent, a conductive agent and a binder in a solvent to obtain slurry A;
s2: uniformly mixing the anode material, the conductive agent and the binder in a solvent to obtain slurry B;
s3: uniformly coating the slurry A on a current collector, and drying to obtain a pole piece A;
s4: and uniformly coating the slurry B on the pole piece A, and drying to obtain the pole piece B, namely the sodium supplementing positive pole piece.
In an embodiment of the present invention, the solvent in the step S1 or S2 is N-methylpyrrolidone (NMP); the mass ratio of the addition amount of the solvent to the sodium supplementing agent or the positive electrode material is 1:1-4:1.
In the embodiment of the present invention, the drying step in the step S3 or S4 is to sufficiently dry the slurry, and thus the drying purpose may be achieved.
In an embodiment of the present invention, the current collector in the step S3 is an aluminum foil.
In an embodiment of the present invention, the coating thickness in the step S3 or S4 is 50 μm to 100 μm.
Embodiments of the present invention will be further described with reference to specific examples, but the embodiments of the present invention are not limited thereto. For process parameters not specifically noted, reference may be made to conventional techniques.
1. The sodium-supplementing positive pole piece and the specific embodiment of the preparation method thereof
Example 1
The preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing sodium carbonate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of 1:2 of sodium carbonate to NMP, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain a slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 50 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h at 110 ℃ in a blasting way to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 1:9, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared by the embodiment is the sodium supplementing positive electrode plate provided by the invention.
The sodium supplementing positive electrode plate prepared by the embodiment comprises an aluminum foil, and a sodium supplementing layer and a positive electrode material layer which are sequentially arranged on the aluminum foil from inside to outside, wherein the positive electrode material layer comprises sodium iron sulfate, SP and PVDF, and the sodium supplementing layer comprises sodium carbonate, SP and PVDF; the area density ratio of the sodium supplementing layer to the positive electrode material is 1:9; sodium carbonate in the sodium supplementing layer: SP: PVDF has a mass ratio of 90:5:5; sodium iron sulfate in the positive electrode material layer: SP: the mass ratio of the binder is 90:5:5.
Example 2
The preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing a sodium manganate positive electrode material, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of 1:1 of the sodium manganate positive electrode material to the NMP, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain a slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 50 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h by blowing at 110 ℃ to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 1.4:8.6, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared in this embodiment is the sodium-supplementing positive electrode plate provided in the invention, and the specific structure is described in reference to embodiment 1.
Example 3
The preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing quaternary positive electrode materials, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of the quaternary positive electrode materials to NMP of 1:1, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain a slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 80 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h by blowing at 110 ℃ to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 2:8, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared in this embodiment is the sodium-supplementing positive electrode plate provided in the invention, and the specific structure is described in reference to embodiment 1.
Example 4
The preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing sodium carbonate, SP and PVDF according to the mass ratio of 80:4:2, adding NMP according to the mass ratio of 1:2 of sodium carbonate to NMP, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain a slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 50 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h at 110 ℃ in a blasting way to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 1:9, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared in this embodiment is the sodium-supplementing positive electrode plate provided in the invention, and the specific structure is described in reference to embodiment 1.
Example 5
The preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing sodium carbonate, SP and PVDF according to the mass ratio of 96:10:5, adding NMP according to the mass ratio of 1:2 of sodium carbonate to NMP, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain a slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 50 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h at 110 ℃ in a blasting way to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 1:9, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared in this embodiment is the sodium-supplementing positive electrode plate provided in the invention, and the specific structure is described in reference to embodiment 1.
2. Comparative example
Comparative example 1
The comparative example adopts a mode of directly mixing a sodium supplementing agent and a positive electrode material to prepare slurry, and the specific preparation method is as follows:
s1: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5;
s2: weighing sodium carbonate according to the mass ratio of the sodium iron sulfate to the sodium carbonate sodium supplementing agent of 95:5;
s3: and adding NMP according to the mass ratio of the total mass of the sodium iron sulfate and the sodium supplementing agent to the NMP of 1:2.2, and performing high-speed dispersion.
However, it was found in the course of the experiment that as the dispersion proceeds, the slurry temperature was continuously increased, gradually exhibiting a gel state, and a slurry which could be normally coated could not be obtained. This indicates that the main material of the positive electrode material reacts with the sodium carbonate composite material, and the preparation of the slurry and the preparation of the sodium-supplementing positive electrode sheet cannot be performed through direct mixing.
Comparative example 2
The comparative example adjusts the coating sequence of the sodium supplementing agent and the positive electrode material in the sodium supplementing positive electrode plate, and the preparation method of the sodium supplementing positive electrode plate comprises the following steps:
s1: respectively weighing sodium iron sulfate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of sodium iron sulfate to NMP of 1:2.2, performing high-speed dispersion, and uniformly mixing to obtain slurry A;
s2: respectively weighing sodium carbonate, SP and PVDF according to the mass ratio of 90:5:5, adding NMP according to the mass ratio of 1:2 of sodium carbonate to NMP, performing high-speed dispersion, and uniformly mixing to obtain slurry B;
s3: setting parameters of a coating machine to enable the coating thickness to be 200 mu m, uniformly coating the slurry A on an aluminum foil, and drying the coated pole piece for 0.5h at 110 ℃ in a blasting way to obtain the pole piece A;
s4: setting the surface density ratio of S3 to S4 to be 9:1, and uniformly coating the slurry B on the dried pole piece A according to the surface density of the sodium supplementing layer obtained in S3. And (3) carrying out forced air drying on the coated pole piece for 0.5h at 110 ℃, and then carrying out vacuum drying for 12h at 120 ℃ to obtain a pole piece B, namely the sodium supplementing positive pole piece.
The positive electrode plate prepared in the comparative example comprises an aluminum foil, and a positive electrode material layer and a sodium supplementing layer which are sequentially arranged on the aluminum foil from inside to outside, wherein the positive electrode material layer comprises sodium iron sulfate, SP and PVDF, and the sodium supplementing layer comprises sodium carbonate, SP and PVDF; the surface density ratio of the positive electrode material layer to the sodium supplementing layer is 9:1; sodium carbonate in the sodium supplementing layer: SP: PVDF has a mass ratio of 90:5:5; sodium iron sulfate in the positive electrode material layer: SP: the mass ratio of PVDF is 90:5:5.
3. Specific examples of sodium ion Battery Using the sodium-supplementing Positive electrode sheet of the invention
Example 6
The sodium-supplementing positive electrode plates prepared in examples 1 to 5 are rolled and then cut into positive electrode plates with phi 14mm, the positive electrode plates are respectively matched with metal sodium plates with phi 16mm, and the electrolyte is a high-chlorine +EC +PC +EMC system, so that the power-saving battery is assembled.
4. Experimental example
Experimental example 1
In the experiment, the preparation method of the electric buckling battery of the embodiment 6 is utilized, the electric buckling batteries prepared in the experimental example and the comparative example are subjected to charge and discharge capacity test, and the test parameters are set as follows: charging to 4.5V at 0.1C rate, then charging at 4.5V at constant voltage, and charging at 0.02mA, wherein charging is completed at 0.1C rate to 2.0V (nominal specific capacity is 120 mAh/g), the measured first charge-discharge curves are shown in FIGS. 1-6, and the first charge-discharge capacities obtained from the charge-discharge curves are shown in Table 1.
TABLE 1 first charge-discharge capacity and coulombic efficiency of rechargeable batteries
As can be seen from table 1, the sodium-supplementing positive electrode materials of examples 1 to 5 significantly improve the first charge capacity of the battery, and especially the sodium carbonate sodium supplement greatly improves the first charge capacity of the battery, so that the positive electrode material can maintain its original capacity in the subsequent charge and discharge cycle process. In addition, the first charge-discharge capacity of the positive electrode plate without sodium supplementation is far lower than that of the positive electrode plate without sodium supplementation, and the positive electrode material layer and the sodium supplementation positive electrode plate of the sodium supplementation layer which are sequentially arranged on the aluminum foil from inside to outside are also lower than that of the positive electrode plate with sodium supplementation provided by the invention, and the first coulomb efficiency is extremely low and is only 22.47%, because ferrous in the positive electrode material is easy to oxidize, and the oxidation of ferrous is easy to cause in a heating and drying step after each coating.
Experimental example 2
The experimental example tests the cycle performance of the button cell assembled by the sodium supplementing positive pole piece through a cycle charge-discharge experiment
The cycle performance test parameters of the power button cell are set as follows: charging to 4.5V at 0.1C rate, then charging at 4.5V at constant voltage, and charging at 0.02mA current is completed, and discharging to 2V at 0.1C rate (nominal specific capacity according to 120 mA/g). The test results of the buckling cycle charge-discharge curves of the buckling batteries assembled by the sodium supplementing positive electrode plates in the embodiment 1 and the embodiment 2 are shown in fig. 7 and 8 respectively, and it can be seen from the graphs that after the sodium supplementing agent plays a role in supplementing sodium, the charge-discharge capacity tends to be stable, the electrochemical performance of the positive electrode material is ensured to be free from loss, the play of the charge-discharge capacity of the positive electrode material during the charge-discharge of the subsequent cycle is not influenced, and the positive electrode material provides stable energy density in the subsequent charge-discharge cycle.
Claims (8)
1. The sodium supplementing positive pole piece is characterized by comprising a current collector, and a sodium supplementing layer and a positive pole material layer which are sequentially arranged on the current collector from inside to outside, wherein the positive pole material layer does not contain sodium supplementing agent, the positive pole material layer comprises sulfate polyanion type positive pole materials, and the sodium supplementing layer comprises sodium supplementing agent.
2. The sodium-compensating positive electrode sheet according to claim 1, wherein the sodium-compensating agent is one or more selected from the group consisting of sodium carbonate, sodium citrate, sodium oxalate, sodium manganate positive electrode material, and quaternary positive electrode material.
3. The sodium-compensating positive electrode sheet of claim 1, wherein the areal density ratio of the sodium-compensating layer to the positive electrode material layer is 1:9 to 4:6.
4. The sodium-compensating positive electrode sheet of claim 1, wherein the sodium-compensating agent in the sodium-compensating layer: conductive agent: the mass ratio of the binder is 80-96:4-10:2-5.
5. A method for preparing the sodium-supplementing positive electrode sheet according to claim 1, comprising the following steps:
s1: uniformly mixing a sodium supplementing agent, a conductive agent and a binder in a solvent to obtain slurry A;
s2: uniformly mixing the anode material, the conductive agent and the binder in a solvent to obtain slurry B;
s3: uniformly coating the slurry A on a current collector, and drying to obtain a pole piece A;
s4: and uniformly coating the slurry B on the pole piece A, and drying to obtain the pole piece B, namely the sodium supplementing positive pole piece.
6. The method for preparing a sodium-compensating positive electrode sheet according to claim 5, wherein the drying temperature in the steps S3 and S4 is 100 to 150 ℃.
7. The method for preparing a sodium-compensating positive electrode sheet according to claim 5, wherein the drying time in the step S3 is 0.5-2 h, and the drying time in the step S4 is 0.5-12 h.
8. A sodium ion battery using the sodium-compensating positive electrode sheet of any one of claims 1-4.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117253988A (en) * | 2023-11-17 | 2023-12-19 | 江苏中兴派能电池有限公司 | Positive plate and preparation method thereof, battery cell and battery and preparation method thereof |
| CN117727948A (en) * | 2024-02-07 | 2024-03-19 | 深圳海辰储能科技有限公司 | Negative current collector, preparation method thereof, sodium secondary battery and electric equipment |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117253988A (en) * | 2023-11-17 | 2023-12-19 | 江苏中兴派能电池有限公司 | Positive plate and preparation method thereof, battery cell and battery and preparation method thereof |
| CN117253988B (en) * | 2023-11-17 | 2024-01-30 | 江苏中兴派能电池有限公司 | Positive plate and preparation method thereof, battery cell and battery and preparation method thereof |
| CN117727948A (en) * | 2024-02-07 | 2024-03-19 | 深圳海辰储能科技有限公司 | Negative current collector, preparation method thereof, sodium secondary battery and electric equipment |
| CN117727948B (en) * | 2024-02-07 | 2024-05-14 | 深圳海辰储能科技有限公司 | Negative current collector, preparation method thereof, sodium secondary battery and electric equipment |
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